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THE MASTICATORY ORGAN
Functions and Dysfunctions
Rudolf Slavicek
First english edition 2002 
Slavicek, Rudolf:
The Masticatory Organ: Functions and Dysfunctions / Rudolf Slavicek. - Klosterneuburg: Gamma Med.-wiss. Fortbildungs-AG,
2002
ISBN 3-9501261-1-2
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Important Note:
All the information in this book has been carefully researched by the author and meticulously processed by the publis-
her. These data essentially conform with the scientific standards that were prevalent at the time the work was com-
pleted. However, errors cannot be excluded in spite of meticulous effort. The applicability of the data mentioned in
this work to specific treatment measures can only be judged by a specialist; the specialist is requested to review the
knowledge presented here in the light of his own experience, to the best of his/her knowledge and belief.
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Printed in Austria
Cover design: Haslinger Design, Klosterneuburg
Overall production: Gamma Dental Edition, Klosterneuburg
Printing and binding: Kärntner Druckerei, Klagenfurt
Publisher: GAMMA Medizinisch-wissenschaftliche Fortbildungs-AG, Klosterneuburg
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Contents
5
Contents
Introduction 11
Chapter 1: EVOLUTION 17
Evolution of mankind and the masticatory organ 18
The scientific discussion 19
The new species "Homo" 22
Evolutionary hypothesis regarding hominization, relative to the masticatory organ 27
Oral communication in hominid evolution 31
Expression and Signaling 32
Communication, Information 32
Description 33
Evolution of the psyche - the limbic system 34
Effects of evolution - an overall view 38
Evolution of the masticatory organ from the viewpoint of tooth morphology 48
The new organ- a cybernetic feedback control mechanism 50
Thinking in terms of a feedback control mechanism 51
The organism and its so-called masticatory organ - definition 56
Chapter 2: STRUCTURES 59
The Cranio-Mandibular System (CMS) 60
Structures of the cranio-mandibular system in detail (CMS=TMJ) 62
Bony structures 62
Ligamentary structures 65
The articular disk 66
Retro-articular structures 66
The system-immanent musculature of the mandibular joints 71
Caput profundum masseteris 71
Musculus pterygoideus lateralis caput superius 74
The frontal head of the Musculus temporalis 75
The synovial apparatus 84
Extended ligamentary attachments 84
Ligamentum sphenomandibulare 84
Ligamentum stylomandibulare 86
Ligamentum stylohyoideum 86
Ligamentum pterygospinale 86
The so-called "alpha"ligament 86
Summary 89
The neuromuscular system (NMS)- muscles of the masticatory organ 90
Musculus temporalis 96
Musculus masseter 97
Musculus pterygoideus medialis 98
Musculus pterygoideus lateralis caput inferius 99
Musculus mylohyoideus 101
Musculus digastricus 103
Musculus stylohyoideus 106
Musculus geniohyoideus 106
Musculus genioglossus 108
Musculus hyoglossus 108
Musculus styloglossus 109
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6
Musculus linguae (the tongue) 109
The musculature of the soft palate, the pharyngeal vestibule and the pharynx 110
Musculus levator veli palatini 111
Musculus levator uvulae 112
Musculus glossopalatinus 112
Musculus palatopharyngicus 112
Musculus tensor veli palatini 112
The pharynx - pharyngeal head - throat 113
Epipharynx 113
Mesopharynx 113
Hypopharynx 114
Muscles of the larynx 116
Muscles related to the posture of the head, the throat, neck and thoracic girdle 118
The pre-vertebral muscles 125
Musculus rectus capitis ventralis 125
Musculus longus capitis 125
Musculus longus colli 125
Musculi scaleni 127
The infrahyoid muscles 127
Musculus sternohyoideus 127
Musculus omohyoideus 129
Musculus sternothyreoideus 129
Musculus thyreohyoideus 129
Musculus sternocleidomastoideus 131
Musculus trapezius 132
Musculus levator scapulae 134
Summary 134
Occlusion - Articulation 136
Ontogenesis of the masticatory organ 137
The postnatal period 140
The developmental period of deciduous dentition 156
The first developments in speech 158
Problems relating to the sleeping position 158
Respiratory problems 159
The functional period of mature deciduous dentition 159
Summary of the functional period of "deciduous dentition" 160
The first functional period of changing dentition 161
The second functional period of changing dentition 172
The third functional period of changing dentition 178
The discussion on changing dentition 183
Mature, complete dentition 187
Compensation mechanisms 188
Dento-alveolar compensation 189
Vertical compensation 189
Articular compensation 189
So-called occlusion concepts 192
The functional areas of occlusion 193
The functional area of the frontal dental arch 193
The frontal lateral dentition area 197
Functional areas of the premolars 197
The morphology of the premolars 199
The occlusal planes 202
Definitions 202
Spheres of occlusion 207
The behavior of the occlusal plane and spheres in comparative research 207
Functional lines of occlusion 210
Normal dentition and malocclusions 212
R. Slavicek • The Masticatory Organ
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Contents
7
The characteristics of "ideal" dentition (Class I) 212
So-called dysgnathias 212
The morphological syndrome of Class II/1 213
The morphological syndrome of Class II/2 216
The morphological syndrome of Class III 217
Chapter 3: FUNCTIONS 219
Mastication 220
The "eating tools" or "guzzling tools" 220
Reptiles 220
Carnivores 221
Herbivores 225
The phylogenetic changes from Hominoids to Hominids to Homo sapiens 226
The Pongids 226
Homo sapiens 230
Mastication- definitions, scientific discussion 234
Speech 258
On the physiology and pathophysiology of speech in a non-abraded dentition 260
Occlusion and speech 263
Posture - On the physiology and pathophysiology of body- and head posture in
modern humans 265
Body posture of healthy humans 267
The lateral view 267
Anterior view 268
Posterior view 268
Esthetics"- the human appearance as a function 271
Objective and subjective esthetics 272
Harmony - Symmetry - Proportion 274
Cephalometry and Esthetics 275
General theories of proportion in human esthetics 276
The function of stress management 281
Functional patterns in clenching and bruxism 291
The role of so-called occlusion concepts in the parafunctionne 294
Occlusion concepts 296
The concept of balanced occlusiona 296
The concept of group function on the laterotrusion side 298
The concept of canine-guided occlusion 298
The sequential concept 298
Malocclusions 300
Summary and final observations 301
The CMD patient with primary psychological disease 302
The psyche, the masticatory organ and environmental factors 302
Chapter 4: DIAGNOSTICS 305
Clinical functional diagnostics 306
Diagnostics 311
The patient's main concern 313
The complete medical anamnesis 313
The dental anamnesis 314
The pain anamnesis 315
The actual clinical functional analysis (Physio-diagnostics) 315
The comparative muscle analysis 316
Clinical procedures 317
Palpation 320
The shoulder-neck region 320
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8
The atlanto-occipital connector 323
Musculus temporalis 323
The cranio-mandibular system (mandibular joints) 325
Musculus pterygoideus medialis 330
Musculus masseter 330
The floor of the mouth 330
The tongue 332
The infrahyoid musculature 336
Examination of the movements of antagonistic muscle groups 337
Free mobility- the psychological imbalance resulting 
from evolutional changes in the limbic 
system
The importance of teeth in the management of
emotions should be reemphasized. Semantically,
we may state graphically that Homo "bares his
teeth to the world". This emotional aspect of den-
tition is by no means solely a human privilege, but
a traditional symbol of strength and a threatening
device in other species. However, the display of
teeth also emphatically reflects emotions by way
of expressing friendliness, laughter and smiling.
Facial expression is strongly governed by the
teeth, among other factors.
Even after the evolution to human beings, the cani-
ne, the symbolic weapon of Primates (especially in
males), disintegrated in the buccal-labial aspect.
However, it is still regarded as an aggressive tooth
and the focal point for external and internal
aggression (see ill. 19-20, p. 39). Except for the
brain and its development, the extremely rapid
phase of evolutionary hominization affected no
other organ as emphatically as it did the organ
which, in consideration of its multiple functions, is
still falsely referred to as the "masticatory organ".
If we attempt to identify the main reason for the
enormously successful human creation and popu-
lation of an ecological niche, it certainly would be
the development of the complex and abstract
form of communication which we call "speech".
The development of speech as a highly specialized
form of breathing and the resultant explosive deve-
lopment of the brain associated with the exponen-
tial enhancement of communicative capacity, are
certainly the most striking events in hominization.
38
R. Slavicek • The Masticatory Organ
- the development of communicative 
speech
- the development of functional 
asymmetry in the brain
- the expansion of consciousness and 
the emergence of self-consciousness
- the psychological imbalance resul-
ting from evolutional changes in the 
limbic system
The canine, the symbolic weapon of Primates
(especially in males), disintegrated in the buc-
cal-labial aspect. However, it is still regarded
as an aggressive tooth and the focal point for
external and internal aggression 
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Evolution
39
Ill.. 19: The
non-integrated
(separate) canine
in pongids
(males) is to be
interpreted as a
sign of domi-
nance, strength
and aggression.
It is a "symbolic
weapon" and
should be dis-
tinguished, for
instance, from
the tiger's
canine which is
a true instru-
ment for killing.
Ill. 20: The human canine reintegrated
into the maxillary arch in its functionality. 
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R. Slavicek • The Masticatory Organ
40
"Hand in hand" with these developments, the
hand was modified to become a highly-differen-
tiated "grasping" organ. "Handedness" first beca-
me possible when humans became bipeds.
Conversion of speech into an additional and more
abstract form of communication, namely writing,
accelerated the emergence of Homo sapiens. The
development of speech had structural prerequisi-
tes and the result of these major formative impul-
ses was the modification of the entire viscerocra-
nium. In turn, the ensuing brain development
necessarily brought about a further structural
change in the stomatognathic region because of
the enormous increase in volume. Therefore, the
form of the recent Homo sapiens dental arches
became, simultaneously, both the cause and effect
of anthropogenesis (see ill. 21-23, p. 41).
Concurrently, the additional phylogenic step of
"standing erect" took place. Although this chan-
ge in posture had the advantage of freeing the
hands for important tasks, it also significantly
extended the functional duties of the stomato-
gnathic system. The head with its increasingly
altered proportions, due to the brain, was no lon-
ger leaning far to the front, hanging from the
nuchal ligament and carried by strong neck
muscles, but muscularly tensed and balanced on
the relatively small articular surface of the atlan-
to-occipital connector, similar to the rig of a sai-
ling ship. Dorsally, the change took place through
the atlanto-occipital attachment, ventrally
through the complex system of the infrahyoid
and suprahyoid muscles which, through their
attachment to the mandible, indirectly assumed
the responsibility of head posture with the assi-
stance of the true masticatory muscles.
The entire spinal column underwent major modi-
fications, conditioned by stress. The kyphotic
situation of the primate cervical vertebrae under-
went a phylogenic modification and developed a
complex, alternating lordotic, architecture (see ill.
24, p. 42). Of great interest to us is the fact that,
at the time of birth, the human spine corresponds
to that of a newborn primate. At birth, the fetal
posture of the spine and head is the same in pri-
mates and Homo sapiens (see ill. 25-26, p. 42, 43).
The spinal column was restructured over millions
of years of phylogenic time. Ontogenetically it
occurs after birth during the short period the
infant strives to attain an upright position.
Humans created themselves through their
descriptive speech.
Therefore, the form of the recent Homo sapi-
ens dental arches became, simultaneously,
both cause and effect of anthropogenesis 
The entire spinal column underwent major
modifications, conditioned by stress. 
At birth, the fetal posture of the spine and
head is the same in primates and Homo sapi-
ens.
Kyphosis
Lordosis
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Evolution
41
Ill.. 21: The human dental arch in
intercuspation. 
Ill. 22: The sketch shows the strong
transversal development in the posteri-
or area and the reintegration of the
canine into the arch. The arched form
could be a result of the enormous
development of the brain.
Ill. 23: The entirely different architec-
ture of the spinal column of a semi-ter-
restrial primate in comparison to the
bipedal human.
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R. Slavicek • The Masticatory Organ
42
Ill. 24: A comparison between humans and primates shows the approximately identical cranial-spinal architecture. The position of
the foramen occipitale magnum is displayed in red. The dramatic change in adults is clearly seen. The major alterations in inclina-
tion of the foramen occipitale magnum are illustrated here, i.e., posterior rotation in humans and ventral rotation in pongids. 
Ill. 25: The fossa are positioned in a wide fashion laterally and not overlapped by the neo-cranium. 
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Evolution
43
Ill. 26: The small braincase with a ridge for insertion of postural musculature. 
Ill. 27: Overlays of development of the cranial base and on the palatinate plane in chimpanzees prove that there are no noticeable
directional changes during growth. 
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R. Slavicek • The Masticatory Organ
Standing upright and the enormous demands of
restructuring and modification made on the func-
tional areas associated with it take place within a
few months of life (see ill. 28, left). 
Phylogenetically, this change in structure strongly
affects the structure of the pelvis and, conse-
quently, the female birth canal. This aggravated
the problem resulting from the increasing volume
of the neurocranium and, due to the development
of the infant, made it necessary for the infant to be
born "prematurely". This strategic and complete
modification of the spinal column and pelvic gird-
le also explains, in a very broad sense, the relati-
onship between problems in posture on the one
hand, and functions and dysfunctions within the
masticatory organ on the other. This subject will
be discussed in detail later.
In the evolution to Homo sapiens, the complex
muscular structures of the primate cranium and
the masticatory organ were completely altered in
terms of concept. This was accomplished on the
one hand by posture, and on the other hand
through the new, additional and important func-
tions of the human masticatory organ. Just the
stabilization of the mandible against the functio-
nal surface of the articular eminence during
upright motion requires an entirely new system.
The evolutionarydevelopment of "head balance"
appears to assign the atlanto-occipital joints a spe-
cific function, which includes their adopting the
role of an additional sense organ (compare
Tilscher).
Upright posture also necessitated a major change
in the respiratory apparatus. Respiration and the
development of speech had a great influence on
evolutionary phylogenic development. The respi-
ratory passages sank more dorsally and the see-
mingly illogically conceived intersection of respi-
ratory passages with the digestive tract became
even more problematic, as the epiglottis mecha-
nism was compromised in its function.
Constrictions in the respiratory passages are often
compensated for by modifications in posture.
The stress-related modification of the pelvic gird-
le and the brain-related increase in cranial volume
necessitated a strategically "premature" birth
among humans. Post-natal development of the
human brain nearly triples its volume, in contrast
to post-natal brain development in pongids,
among which only the chimpanzee, the most
44
Tilscher, H.: Die Kopfgelenke – ein zusätzliches Sinnesorgan?
Sonderdruck aus: Reinhardt, B. (Hrsg.): Das Bewegungsseg-
ment der Wirbelsäule im Blickfeld der orthopädischen
Rückenschule. Med. Lit. VerlagsgesmbH., Uelzen 1993
Ill. 28: During the ontogenetic process of attaining the
upright position, the horizontal semicircular canals must
remain horizontal. For this reason, alterations are made in
the system.
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Evolution
developed of the great apes, exhibits a minimal
amount of post-natal (brain) growth. The neu-
rocranium increasingly overlapped the viscerocra-
nium, affecting, above all, the relative position of
the temporo-mandibular joints to the cranium.
Phylogenetically, upright posture necessitated
complete restructuring of the cranial base, especi-
ally the position of the foramen magnum. By
means of counter-rotation, the vestibular appara-
tus must compensate for the dorsally rotating
components of upright posture (see ill. 29 and 30,
right; ill. 31 and 32, p. 46).
In ontogenesis, this slow, evolutionary develop-
ment is represented in a dramatic time lapse
sequence. The ontogenetic change in posture in
the first post-natal year in humans compels a rota-
tion of approximately 45 degrees in the foramen
magnum. This ontogenetic change to the upright
position, which takes place at the end of the first
post-natal year, and the changes in the dynamic
architecture of the spinal column associated with
it, cause a structural change in the entire cranial
base. The temporal and sphenoid bone are especi-
ally affected by the corrections that take place in
the position of the organs responsible for equili-
brium (horizontal semicircular canals). The fora-
men magnum inflects about 45 degrees posterior-
ly during this development. This extreme rotation
influences the entire cranial base and thereby,
above all, the structures of the temporal bone, as
the vestibular organ with its horizontal semi-cir-
cular canals must necessarily duplicate the
upright posture.
The shifts in structure might be related to indivi-
dual flexion of the spheno-occipital syndesmosis.
The change in the relationship appears to have a
major influence on the growth and the direction
of growth of maxillary structures (see ill. 33 and
34, p. 46). This would indicate (comp. Sato) that
the individual behavior of the cranial base (flexion
or extension) during ontogenetic development
determines the variable position and relation of
the jaw. The vehement and dramatic development
of the neurocranium and the increasingly compli-
cated birth canals, associated with upright postu-
re, gave rise to even more premature birth during
hominization (see ill. 35, p. 46). The evolutionary
development in the breadth of the neurocranium
compelled concurrent development of the vis-
cerocranium. The sutures reacted to the increa-
45
Ill. 29: The infant primate develops further with no signifi-
cant changes in anterior and vertical growth. 
Delattre, A.: Du Crane Animal au Crane Humain. Masson
edit., S. 104, Paris 1951
Sato, S.: Alteration of Occlusal Plane due to Posterior Dis-
crepancy Related to Development of Malocclusion –
Introduction to Denture Frame Analysis. Bulletin of
Kanagawa Dent. Col., Vol. 15, No. 2, S. 115–123, 1987
Ill. 30: This overlay clearly illustrates the difference in onto-
genetic development. The position of the foramen magnum,
after attaining the upright position, is 35-45 degrees. In
chimpanzees, none of these alterations takes place 
(see ill. 27, p. 43). 
40 – 45°
Flexion
Extension
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R. Slavicek • The Masticatory Organ
46
Ill. 31: This sketch from Delattre and Fenart shows the extent
of movements that take place. 
Ill. 32: Rotation and counter-rotation - upright posture and
the vestibular system.
Ill. 33: The structure of the cranial base is of great signifi-
cance in cephalometric analysis.
Ill. 34: Example of a cephalometric overlay.
Ill. 35: This graph of post-natal brain development illustrates
the dramatic increase in humans in comparison with hominoids. 
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Evolution
47
Ill. 37: The distinct "herbivorous", transversal abrasion in the
adult chimpanzee is evident. 
TEST OF SIGNIFIANCE FOR ASYMMETRY OF ANGLE AOI DURING
MASTICATION OF CARROT BY Homo sapiens AND
Macaca fascicularis
No. of No. of Chews Mean Angle AOI
Individuals Left Right Left Right T-Value
Macaca
fascicularis 3 60 60 87.33 ± .30° 87.93 ± .26° 1.504
(d.f.=118)
Homo Sapiens 5 60 60 88.70 ± 1.11° 83.01 ± .89 4.01*
(d.f.=118)
*pshould be regarded as adaptive mech-
anisms. 
The morphology of the primate dentition,
especially the molars, approximates that of
humans.
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Evolution
strong abrasion (see ill. 37, p. 47). From the ante-
rior view, the masticatory loop is symmetrical.
Asymmetrical masticatory loops should be regar-
ded as a result of brain-polarization. The denti-
tion approximates that of humans, a tendency
towards mesioclusion is seen. The role of the four
front teeth is apparently an unimportant one. The
molars abrade early. The abrasion model is similar
to the basic model in herbivores.
Dental arches in modern humans are characteri-
zed by the buccal-labial overbite of the maxillary
teeth. During the last 150 years, a new human
phenotype has emerged as a result of the altered
eating habits of our western industrial society.
Human beings tend to live much longer, the
masticatory organ is not subject to food-related
abrasion, and the developmental grooves are
retained to a large extent. This induces changes in
the functional model of the masticatory organ.
Because of changes in the environment and in
social structures, exogenous pressures at the
somatic as well as psychic level are significantly
increasing. As a result of the incredibly numerous
and increasing forms of communication in recent
times, it is quite possible that the human brain
will be greatly modified in the future.
49
During the last 150 years, a new human phe-
notype has emerged as a result of the altered
eating habits of our western industrial society. 
Alt K. W. Türp J. C.: Die Evolution der Zähne. Phylogenie
– Ontogenie – Variation. Quintessenz Verlag, Berlin 1997
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The result of all these changes, which took place
during hominid evolution, was a new race, name-
ly the human race. This unique and extremely
successful evolutionary development of the new
species was characterized by the function of the
human mind. The most important milestone in
human brain development was the emergence of
"self-consciousness". The new functions of the
masticatory organ were intimately connected with
the extremely expansive functional development
of the brain. In addition to its nominal function,
viz. mastication, it was also distinguished by the
function of speech. In order to stand upright and
become a true biped, major contributions were
required from the neuromuscular structures asso-
ciated with head and body posture.
Becoming conscious of one's identity and the
resulting emergence of an individual, i.e. esthetic
consciousness, created the "face", whose individu-
ality and expression are substantially influenced
by the masticatory organ. The loss of a balanced
psychological polarity extended the functional
range of the organ and created a backdrop for the
management of stress, which was brought about
by new areas of social conflict. These new tasks
could only be fulfilled by effecting drastic changes
in structural areas.
With the purpose of instigating clearly defined
approaches of thought, I feel justified in regarding
the masticatory organ as a separate feedback con-
trol system in the overall control organism, and in
50
R. Slavicek • The Masticatory Organ
The new organ - 
a cybernetic feedback
control mechanism
This unique and extremely successful 
evolutionary development of the new species
was characterized by the function of the
human mind. 
... the "face", whose individuality and expres-
sion are substantially influenced by the masti-
catory organ. 
... created a backdrop for the management of
stress, which was brought about by new areas
of social conflict. 
Cybernetics
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classifying it within the dynamic hierarchy of the
overall system with its ever-changing priorities.
The theoretical conclusion of this thought process
must lead to a relocation of the organism into its
own individual environment, created by its self-
consciousness. With the help of this theory of a
feedback control mechanism, it should be possible
to more easily follow, and better understand, diag-
nostic steps and therapeutic approaches with
regard to the masticatory organ.
Thinking in terms of a 
feedback control system
The concept "Feedback control mechanism cyber-
netics" was introduced in science in 1948 by
Norbert Wiener, although a general "automatic
regulation" concept had previously been propa-
gated by H. Schmidt (1941). Cybernetics derives
from the Greek word for the "helmsman" who, by
his decisions, determines the course and also, in
the sense of a closed system, causes reactive changes
to occur in all of the dependent inner sub-systems.
The simple example of a well-trimmed sailing
ship makes this evident and comprehensible: if
the helmsman alters the course, the entire system
is forced to adjust. External influences are altered
relative to the ship, although they actually may
remain the same. The "true" wind remains
unchanged, the virtual wind changes. The posi-
tion of sails needs to be modified, and this alters
both the speed and position of the ship. All of the
dynamic parameters must adapt, although the
environment has not changed. On the other hand,
if there is an alteration in environmental condi-
tions, e.g., in the force or direction of the wind,
then naturally the entire dynamics of the ship i.e.,
the system "ship" and all of its sub-systems, must
adapt. This example can be detailed in a variety of
ways, but it suffices to indicate the compactness of
a feedback control system which, within itself, is
subject to permanent modification and, simulta-
neously, to external influences. The function of a
"helmsman" is not, however, a rigid, hierarchical-
ly static function, but rather can be utilized
dynamically in other positions. When the ship
loses its ability to adapt, a shipwreck is imminent.
51
Evolution
Wiener, N.: Cybernetics or Control and Communication in
the Animal and the Machine. Hermann Verlag, Paris 1948
Fasching, G.: Kaleidoskop der Wirklichkeiten. Springer
Verlag, Wien 1999
The theoretical conclusion of this thought
process must lead to a relocation of the
organism into its own individual environ-
ment, created by its self-consciousness. 
When the ship loses its ability to adapt, a
shipwreck is imminent.
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The concept of feedback control can be applied to
organisms. For the living organism, it may be
applied and considered from both a somatic 
and psychic point of view and, naturally, from a
psychosomatic viewpoint as well.
We will use two examples from the literature to
learn to think in terms of feedback control. The
following will consider the position of the orga-
nism in its environment from two fields of influ-
ence: from the field of "reception", which per-
ceives the environment, and the field of "reaction",
which responds to the environment. This can be
illustrated by using a simplified scheme from
Uexkuell (see ill. 40, left). If a problem appears in
the vicinity (environment) of the organism and is
judged to be important, the organism reacts
immediately by offering a solution to the problem
(see ill. 41, left). This simple feedback control
mechanism shows the direct possibility of prob-
lem solving without an undue length of process-
ing time.
This may also be illustrated by a further simple
example: an organism, e.g., an animal living in
open nature, perceives another organism in its
environment. This effects an "assessment of signif-
icance" and possibly, depending on previous expe-
rience, an "assignment of significance". The result-
ing reaction might, for example, call for "escape".
If this is carried out, problem solving has taken
place which, if successful, gives rise to an imprint
in the sensory area of "experiences". From the
viewpoint of modern brain physiology, the word
"experience" may be interpreted as the structuring
of virtual psychons.
The brain researcher Eccles formulated this thesis
regarding the interaction of the mind and brain,
based on theories of quantum physics, in his
micro-localization hypothesis. In this hypothesis,
hecompares the smallest functional unit of the
neural system, the neuron, with the smallest func-
tional unit of the mind, the psychon. The psy-
chon, the postulated "mental" unit, is assigned to
the dendron (neural unit), and can induce a men-
tally instigated neural event. This learning capa-
bility, the building up of experiences, leads to the
said reaction when the typical event occurs, but
may also lead to the reactive solution in the event
of less specific similar incidents. Most environ-
mentally related processes are much more compli-
cated in humans, whose psychosomatic structure
52
R. Slavicek • The Masticatory Organ
Uexkuell, Th. v. (Hg.): Lehrbuch der psychosomatischen
Medizin. Urban und Schwarzenberg Verlag, München 1986
Eccles, J. C.: Die Evolution des Gehirns – die Erschaffung
des Selbst. In: Eccles, J. C.: Die Mikrolokalisations-
hypothese. Piper Verlag, New York, Heidelberg, Berlin 1989
Eccles, J. C.: Do Mental Events Cause Neural Events
Analogously to the Probability Field of Quantum
Mechanics? 227: 411–28, Proc. R. Soc. Lond. (Biol.) 1986
Ill. 40: This sketch, according to Uexkuell, illustrates the
theoretical scheme of any arbitrary organism (animal or
human) as a unit of the psyche and soma, within its skin. 
Ill. 41: When the organism is confronted with a problem in
its environment, it recognizes the problem and assigns it a
degree of importance. Its reaction results in a solution to the
problem. The reaction again flows automatically into the
environment as reality; a direct, cognitive solution is applied
to the problem and the problem is solved. 
Psychosomatics
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is differentiated from that of organisms by "self-
consciousness". In contrast to the "System:
Organism", the human being may be regarded as
the "Supra-system: the Individual", who builds his
own individual environment. This cybernetic
scheme is much more complex than that of an
organism without "self-consciousness" (see ill. 42,
right).
The human, as a supra-system, receives and
processes events through the sub-system, the psy-
che (see ill. 43, right). From this viewpoint, the
distinction between conscious, unconscious and
pre-conscious processes in this scheme deserves
attention. The area of the unconscious and pre-
conscious, for subsequent processing of psychic
stresses, is an important element of the mental
approach to functions of the masticatory organ,
which serves as a platform for stress management.
When considering approaches and successful
attempts to view the masticatory organ as a feed-
back control mechanism, Stallard's scheme of
"organic occlusion" and the much more dynamic
one proposed by Fröhlich deserve investigation
(see ill. 44 and 45, p. 54).
In my lectures and publications, I frequently
introduced an expanded scheme of the position of
the human masticatory organ in the overall
organism (see ill. 46, p. 54). In this scheme, the
somatic areas of the main structures are compared
with the functions of the masticatory organ, but
the somatic and psychic areas of the central 
nervous system are also integrated into the same
feedback control system in order to document the
absolute interdependence of the brain and the
masticatory organ (see ill. 47, p. 55). Worthy of
note are the functions in the center, which
emerged through evolutionary functional expan-
sion (see ill. 48 and 49, p. 55). Speech was one of
the main functions (see ill. 50 and 51, p. 55). The
postural function of the head, because of the
attainment of upright position and becoming a
biped, is a part of the overall human posture (see
ill. 52, p. 55). Esthetic consciousness is listed as a
function of the masticatory organ because the face
is molded by the viscerocranium (see ill. 53, p.
55). One of the significant new functions is stress
management, which is considered to be closely
associated with the psychic aspect, but also with
the environment. Dentition provides a somatic
backdrop for stress management. Clenching and
53
Evolution
Ill. 42: Because of "self-consciousness", unique to humans, a
so-called supra-system is created, possessing its own individ-
ual reality.
Ill. 43: The reception system psyche processes incoming
problems and transposes them into emotions in the somatic
area if they cannot be resolved immediately.
Fröhlich, F.: Die okklusionsbedingten Schmerzen im Kiefer-
Gesichts-Bereich. Schweiz. Mschr. Zahnheilkunde 76, 
S. 764–776, 1966
Stallard, H.: Oral Rehabilitation and Occlusion.
Postgraduate Education School of Dentistry. University of
California S. F.
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R. Slavicek • The Masticatory Organ
54
Ill. 44: The system of dependence of three basic structures,
postulated by Stallard, was the basis of the gnathological
concept of "organic occlusion".
Ill. 45: Fröhlich refined the dependencies and emphasized
the direct influence of occlusion on the jaw joints.
Ill. 46: The cybernetic scheme "masticatory organ", occupying a central position in the organism, which is surrounded by its indi-
vidual environment. Structures and functions are detailed and interrelationships with somatic and psychic areas of the CNS are indi-
cated. 
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Evolution
55
Ill. 47: The central nervous system is
divided, schematically, into a psychic
and a somatic region.
Ill. 50: Speech, the most important
medium of communication, is its main
function.
Ill. 53: The human face is the center
of perception and self-perception.
Ill. 48: The list of functions to be per-
formed and shared by the human mas-
ticatory organ.
Ill. 51: Speech and respiration are an
indivisible unit.
Ill. 54: Bruxism and pressing, as
somatically required zones, serve the
purpose of reducing stress.
Ill. 49: Mastication is the function
which gives the name, but certainly
not the most important one
Ill. 52: The posture of the head, from
the viewpoint of the overall function
of the organ, is one of the main
aspects of phylogenesis.
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bruxing are legitimate functions of the masticato-
ry organ (see ill. 54, p. 55). 
The position of the masticatory organ in relation
to the entire organism and its role within its indi-
vidual environment are clearly described in the
cybernetic scheme. Many, if not most, functional
disorders should be investigated in regard to
causal environmental influences. Of course, from
this point of view the entire organism is regarded
as a feedback control system that must constantly
react to internal and external changes.
The organism and its so-called 
masticatory organ - definition 
As one is apt to use the simplified term "mastica-
tory organ", it would be appropriate to first con-
sider the word "organic": "organ" derives from the
Greek word "organon", which means "tool". The
organ is defined as a morphological unit com-
posed of cells and tissues, which fulfills one or
more functions. It is perfectly justified and practi-
cal to apply Burdach's and Goethe's morphologi-
cal concept, in its original sense, namely a "com-
prehensively dynamic" one. This concept not only
applies to the limited viewpoint of anatomy, but
also to other dynamic forms, e.g., in fine arts.
Organs are parts of entire organisms, structurally
and functionally different but subjugated to
orderly, hierarchical principles. According to
cybernetic thinking, the entire organism is a
dynamic feedback control system. As we have
mentioned, the hierarchical order in this system
should by no means be regarded as a static one.
Rather, it is unprecedented and dynamic, depend-
ing on circumstances. The organism organizes its
hierarchy according to the priority principle, i.e.,
according to the functions required at the
moment. This means that the functions required
for life determine the importance and dominance
of the organs at any particular time. As an exam-
ple, we cite the banal but apropos statement,
"plenus venter non studet libenter": supplying the
necessary amount of blood for digestion reduces
brain activity to a lower level of priority.
56
R. Slavicek • The Masticatory Organ
Many, if not most,functional disorders
should be investigated in regard to causal
environmental influences. 
"Organ" derives from the Greek word
"organon", which means "tool". 
According to cybernetic thinking, the entire
organism is a dynamic feedback control sys-
tem. 
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The principle of the organism may be defined as
follows:
• An organism is a self-regulating, self-orga-
nizing and self-reproducing dynamic system.
• The organism reacts to the environment 
and is permanently subject to its demands.
• The organism must continuously adapt in 
order to cope with these demands and 
requirements.
• Constant adaptation is necessary for life 
support and is therefore the only means of 
survival.
• All organs are involved in this process.
• The organism uses these organic functions 
indiscriminately for the purpse of living and
surviving.
For the "individual" human being, the environ-
ment is to be regarded as an individual reality.
This means that there is no objective environment
for the individual; every human builds his/her
own subjective stage of observation, from which
he/she experiences the individual environment.
Cognizance of this viewpoint is especially impor-
tant for the dentist when he or she is handling a
patient.
• The functions of the masticatory organ are 
intimately connected with functions of the 
brain, both somatically and psychically.
• Along with its functions, the masticatory 
organ has assumed a central position in the 
organism.
• Contact with the environment is established
and maintained through the masticatory 
organ.
• Therefore, environmental factors are very 
important in the evaluation of causality with
regard to functional disorders in the mastica-
tory organ.
• The masticatory organ is also a backdrop for
the psyche, for conscious and unconscious 
processing of problems.
The concept of a feedback control mechanism is
the main theme of this book. Learning about basic
structures is a prerequisite for better comprehen-
sion of the functions. 
57
Evolution
The organism uses these organic functions
indiscriminately for the purpose of living and
surviving.
• The functions of the masticatory organ are 
intimately connected with functions of the 
brain, both somatically and psychically.
• Along with its functions, the masticatory 
organ has assumed a central position in the
organism.
• Contact with the environment is estab-
lished and maintained through the masti-
catory organ.
• Therefore, environmental factors are very 
important in the evaluation of causality 
with regard to functional disorders in the 
masticatory organ.
• The masticatory organ is also a backdrop 
for the psyche, for conscious and uncon-
scious processing of problems.
Adaption
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The structures of the masticatory organ
became characteristics of evolutionary
adaptation to entirely altered conditions.
The most drastic modification was requi-
red in the mandibular attachment to the
skull, brought about by the dramatic chan-
ge in the posture of the head along with
the position of the occlusal plane, relative
to gravity. This modification applies to
bony structures as well as to ligaments and
muscles that posture the mandible relative
to the skull. The dentition in humans is
made up of closed arches, i.e., all teeth are
contacting, possessing an entirely new fun-
ctional make-up and entrusted with new
responsibilities. The neuromuscular system
had to assume very different functions. It is
important for the dentist to realize that
minimizing the importance of extensive
knowledge, especially on the subject of
occlusion, as is currently being practiced
by scientific "trendsetters", may have dele-
terious consequences.
Chapter 2 
Structures
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R. Slavicek • The Masticatory Organ
60
Viewpoints concerning the physiology and patho-
physiology of the temporo-mandibular joints have
undergone frequent change over the last few
decades. The classical definition by Harry Sicher, a
dentist from Vienna, describes the temporo-
mandibular joint very clearly and simply as a syn-
ovial gliding joint with a moveable socket. Instead
of the rather absurd, antiquated anatomical defin-
ition that refers to the articular fovea on the tem-
poral bone, Sicher proposes the notion of a practi-
cal, functional, moveable socket, namely the artic-
ular disk. In addition, this definition clearly points
to the fact that the gliding function of the "condy-
lar disk" unit is in the foreground, and that rota-
tion in the lower joint compartment only supports
the physiology of "gliding" joint movement.
This is especially important in view of the fact
that in diagnostics, until the present time, the
bony relation between the temporal bone and the
condylar process has been overestimated. The
cranio-mandibular system itself can and may only
be viewed from its dynamics; static, bony rela-
tionships are relatively inconsequential. This point
of view is provocative and uncomfortable for some
dogmatic diagnosticians however, and it but should
give them substantial food for thought.
Under normal ligamentary conditions in the inner
capsular structures, translation takes place mainly
in the upper articular compartment and rotation
in the lower articular compartment. The articular
disk, a moveable socket, is "passively" carried
along during translatory lower jaw movement by
The cranio-mandibular
system (CMS)
Sicher, H.: Zur Mechanik des Kiefergelenkes. 27: 27–33, Z.
Stomatol. 1929
Sicher, H.: Functional Anatomy of the Temporomandibular
Articulation. Austral. J. Dent. 55: 73–85, Apr.–Oct. 1951, 
Austral. J. Dent. 24: Jan.–Feb, 1952
Sicher, H.: Functional Anatomy of the Temporomandibular
Joint. In: Sarnat, B. C.: The Temporomandibular Joint.
2nd ed. 28–58, III, Springfield 1964
Gerber, A., Steinhardt, G.: Kiefergelenkstörungen –
Diagnostik und Therapie. Quintessenz Verlags GmbH, 
Berlin 1989
Weinberg, L. A.: Correlations of Temporomandibular
Dysfunction with Radiographic Findings. J. Prost. Dent. 28:
519, 1972
Weinberg, L. A.: Evaluation of the Duplicability of TMJ
Radiographs. J. Prost. Dent. 24: 512–514, 1970
A synovial gliding joint with a moveable sock-
et. 
Under normal ligamentary conditions in the
inner capsular structures, translation takes
place mainly in the upper articular cavity and
rotation in the lower articular cavity. 
Synovia
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ligamentary attachments. Muscular control in this
passive role is supplied by muscles near the joint,
which are inserted in the capsule, in structures of
the articular disk, and (the majority of fibers) in
the condylar process. Supported by gross and
micro-morphological research from recent litera-
ture and based on the results of other studies, I
have postulated a cranio-mandibular system, the
CMS, and replaced the expression "temporo-
mandibular joints" with the structural unit "CMS"
in the cybernetic schematic view of the masticato-
ry organ. This cranio-mandibular system encom-
passes the bony structures of the jaw, the (exten-
ded) connecting and passive centering ligaments,
and the system's active centering muscles (see ill.
1, p. 63).
Under physiological conditions, the condyle of the
condylar process lies permanently in the lower
compartment of the articular disk. The position of
the condyle in the disk is secured by an ingenious
ligamentary apparatus, which dynamically stabi-
lizes the relation between the articular head and
the mobile socket. These stabilizing ligaments
allow for a great degree of rotation. The possibili-
ty of translatory movement in the lower articula-
tion is, as a rule minimal, but may be substantial
in the presence of a loose (individual phenotype or
pathophysiologically altered) ligamentary system.
Under pathological conditions and permanent or
semi-permanent luxation (derangement), the
condyle, or a part of the condyle, is not located in
a proper anatomical relationship to the articular
disk. Nevertheless, in most cases, satisfactory 
compensating function can be achieved.
In addition,the ligaments that connect the
mandible and hyoid to the cranial structure are
classified within the cranio-mandibular system.
These attachments tend to be disregarded from
the viewpoint of function and dysfunction. The
ligaments and also the entire fascia apparatus in
the cranio-cervical region should be evaluated
with regard to their practical relationship with the
"stomatognathic system". The extended ligaments
were an absolute evolutionary necessity for stabi-
lizing the mandible against gravity given the
altered cranial posture.
All of the structural areas within the CMS under-
go lifelong adaptation. The adaptation is con-
fined, under physiological conditions, to minimal
and continuous processes.
61
Structures
Supported by gross and micro-morphological
research from recent literature and based on
the results of other studies, I have postulated
a cranio-mandibular system, the CMS, and
replaced the expression "temporo-mandibular
joints" with the structural unit "CMS" in the
cybernetic schematic view of the masticatory
organ. 
Under pathological conditions and perma-
nent or semi-permanent luxation (derange-
ment), the condyle, or a part of the condyle,
is not located in a proper anatomical relation-
ship to the articular disk. Nevertheless, in
most cases, satisfactory compensating func-
tion can be achieved.
Luxation
Reduction
All of the structural areas within the CMS
undergo lifelong adaptation. 
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R. Slavicek • The Masticatory Organ
Structures of the 
cranio-mandibular system 
in detail (CMS = TMJ)
• Bony structures
• Ligamentary structures, including the 
temporomandibular ligament
• The articular disk
• Retro-articular structures (bilaminar zone)
• The system-immanent musculature system 
for the temporo-mandibular joints
• The synovial-capsule apparatus
• Extended ligamentary attachments
Bony structures
The bony structures consist of the condylar
process of the mandible and the temporal bone.
The impression of an "articular cavity" first
emerges during maturation through the function-
ally dependent articular eminence located in front
of the small articular capitulum and individually
formed as an arch-shaped wall. The articular emi-
nence is developed during growth, by the func-
tional influence of a dynamic occlusion. It
responds to functional influences throughout life.
The condylar process develops a trochlear head,
whose longitudinal axis leads towards the great
occipital foramen in different ways, depending on
the individual. The form of the trochlea is gener-
ally characterized by individual, arch-shaped flex-
ion from the axial view. The articular eminence
and condylar process are often developed slightly
asymmetrically. Occasionally, they are markedly
asymmetrical. This morphological description of
bony structures indicates a strong dependence on
the dental morphology of both dental arches (see
ill. 2 and 3, p. 63 and ill. 4 and 5, p. 64).
Important muscles for articular function in
humans are inserted in the condylar process. The
surfaces of the temporo mandibular joints are cov-
ered with fibrous cartilage. The structures of the
human temporo mandibular joint have no defined
post-glenoidal region. A post-glenoidal process is
entirely absent.
Steinhardt, G.: Die Bedeutung funktioneller Einflüsse für die
Entwicklung und Formung des Kiefergelenkes. Deutsche 
Zahn-, Mund- und Kieferheilkunde 2, 1935
62
The impression of an "articular cavity" first
emerges during maturation through the func-
tionally dependent articular eminence 
This morphological description of bony struc-
tures indicates a strong dependence on the
dental morphology of both dental arches 
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Structures
63
Ill. 2: In this inferior view, we see the articular cavity result-
ing from the anteriorly positioned articular eminence.
Ill. 3: In the lateral side view, a sagittal perspective, the
condylar process is positioned behind the articular eminence.
The intercuspating teeth stabilize and determine the position.
Ill. 1: This symbolic illustration depicts the complete interdependent unity of the system. It consists not only of the joints as such,
but also of the entirety of structures, including the ligaments and the immanent musculature system near the joints.
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R. Slavicek • The Masticatory Organ
Ill. 6: The mandible is connected to the cranium by the articular capsule on the condylar process. The capsular cavity allows rela-
tively unlimited movement.
64
Ill. 4: The mandible, seen from above, shows the arrangement
of both condyles with their oblique longitudinal axes, converg-
ing towards the back, or posteriorly. 
Ill. 5: In this cross-section from a sagittal view, the convergence
of structures with convex-convex characteristics becomes evi-
dent.
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Structures
65
The two bony elements of the right and left tem-
poro-mandibular joints, the condylar process and
the temporal bone, are connected to each other by
a loose (because of functional demands) joint cap-
sule, and are by no means held tightly together.
Ligamentous structures (of the joint)
The joint capsule (see ill. 6, p. 64) is, in general, a
loose sac-like connector. However, it displays ele-
ments that may be regarded as ligamentary rein-
forcement. The "looseness" of the capsular struc-
ture - it is also characterized and distinguished by
the individual phenotype - allows for extensive
physiological mobility of the temporo-mandibular
joint.
Significant reinforcement of the capsule is
achieved by a special construction of fibers that
extend from anterior-superior to the temporal
bone, posteriorly and inferiorly to the ascending
branch and the condylar process of the mandible.
This capsular support is known as the ligamen-
tum temporo-mandibulare or the temporo-
mandibular ligament.
Some fibers extend horizontally to the condyle
itself (see ill. 7, right). Upon closer inspection it is
found that the principle vector of these fibers
repeats itself in the pterygoid-masseter loop. This
strengthening of the capsule serves as a protective
mechanism for the ligament against trauma in
posterior direction. For instance, in the event of a
shove or push or posterior pressure at the chin, the
energy is re-routed in a cranial direction through
this practical attachment. In cases of extreme
trauma, the extension of the ligament at the neck
of the condylar process is frequently a "calculated
breaking point" of the mandible, especially in
infants and adolescents.
In addition, the temporo-mandibular ligament is
one of the practical attachments, which aids the
"bipedal" human in centering the mandible
against the forces of gravity.
Ill. 7: The illustration shows the scheme of fiber patterns.
These are by no means outwardly distinct at the joint.
Rather, they are subject to numerous anatomical variations.
The temporo-mandibular ligament is one of
the practical attachments, which aids the
"bipedal" human in centering the mandible
against the forces of gravity.
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R. Slavicek • The Masticatory Organ
66
The articular disk
The articular disk is attached (beneath the actual
capsular structure) to the joint trochlea by a medi-
an and a more substantially formed lateral liga-
ment. The ligaments are attached so as not to hin-
der rotation of the joint head in the lower portion
of the disk. The ligamentary structures are known
as medial and lateral collateral ligaments (see ill. 8
and 9, left; ill 10 and 11, p. 67).
The articular disk is also secured by two further
ligaments, namely the disco-temporal and disco-
condylar ligaments.
The disco-temporal ligament extends from the
petro-tympanic groove to the disk, and forms the
upper plate of the bilaminar zone. With the
mandible in a retral position it is loose and relaxed.
The disco-condylar ligament is larger and lies, in
a retral position, tautly on the condyle, thereby
tightening the connection between the articular
disk and the articular head. In a protrusive posi-
tion this ligament relaxes. The temporo-condylarligament, on the other hand, tenses by an extreme
open movement and pulls the articular disk some-
what posteriorly (see ill. 12 and 13, p. 68). The
ligaments are also subject to variations, dependent
on the phenotype, as well as to pathophysiological
changes. The site of origin in the petro-tympanic
groove occupies a certain role in the discussion of
functional joint pathology (comp. Bumann).
Retro-articular structures
Between the two lamellae described above is a
highly vascularized pad (see ill. 14 and 15, p. 68,
69) known as retro-articular structures (hydrody-
namic retral pad). The latter ensures hydrody-
namic pressure adjustment in translatory articular
movements, serves as a hydrodynamic placement
mechanism for determining the functional posi-
tion of the temporo-mandibular joints, and also
serves as a hydrodynamic protective mechanism
against posteriorly oriented trauma (see ill. 16-18,
pages 69, 70). The function of this pad has been
described on several occasions, the best functional
description being provided by Zenker, an
anatomist from Vienna.
Ill. 8: The illustration clearly shows the functional rotational
freedom of joints in the lower compartment, in spite of their
taut attachment to the disk.
Ill. 9: The illustration demonstrates the practicality of collat-
eral ligaments. The lateral one is generally more substantially
formed than the medial one.
Zenker, W.: Über die mediale Portion des M. temporalis und
deren Funktion. Österr. Zschr. für Stomatol. 51: 550–554,
1954
Zenker, W., Zenker, A.: Die Tätigkeit der Kiefermuskeln
und ihre elektromyographische Analyse. Zschr. für Anatomie
und Entw. Geschichte 119, 1955
Rees, A., Leonard, A., The Structure and Function of the
Mandibular Joint. J. of the British Dental Association Vol.
XCVI, No 6, March 16: 125–133, 1954
Bumann, A., Groot-Landeweer, G.: Zur Diagnostik und
Therapie des Kompressionsgelenkes. Dtsch. Zahnärzt. Zschr.
Jul. 45 (7 Spec No): 4–6, 1990
Special thanks to the Royal Dental College in
Aarhus/Denmark, for providing pictures (Ill. 10, 11, 14,
15)
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Structures
67
Ill. 11: This preparation shows the confluence of fibers to the condylar process.
Ill. 10: In this posterior view, the firm attachment of the articular disk to the poles is shown.
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R. Slavicek • The Masticatory Organ
68
Ill. 14: This picture shows the sagittal section, in which the inter-relationships are clearly seen. The bilaminar zone is evident. 
Ill. 13: In a protrusive position, the disco-temporal ligament
is taut and the lower layer relaxed. The retral joint area of
the bilaminar zone is filled with veins.
Ill. 12: The illustration is a sagittal view. Red: the sturdy
disco-condylar layer of the bilaminar zone. Blue: the slender
disco-temporal ligament, relaxed in retral position. In retral
position, the disk is positioned on the joint head by the disco-
condylar layer.
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Structures
69
Ill. 15: In this specimen, the disk and retral spaces are raised and unfolded from the condylar process.
Ill. 16: This sketch shows the extension of the bilaminar zone during average inclination of the articular eminence. The disk ends in
the zenith of the joint head, with upright head posture. The blue line passing through the condyle shows the extension of the bilam-
inar zone medially.
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R. Slavicek • The Masticatory Organ
70
Ill. 17: With a rather flat eminence, the disk ends somewhat more posteriorly; the bilaminar zone has adequate possibility to 
position the condyle anteriorly.
Ill. 18: With a steep eminence, the disk clearly lies in a functional anterior position, the bilaminar region extends over the zenith to
the front. This also allows the vascular apparatus to be positioned vertically.
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Structures
71
The immanent musculature system of the
temporo-mandibular joints
The position of the mandible in relation to the
articular eminence, the distance of the mandible
to the maxilla and the isometrically precise steer-
ing of dental arches to each other, are strongly
dependent on and controlled by the immanent
musculature system. I believe that the CMS mus-
cles, in view of their responsibilities, should not be
grouped together with the true masticatory mus-
cles. The muscles involved in this region are the
upper head of the lateral pterygoid, the "deep
head" of the masseter and, in approximately 30%
to 40% of cases, the fourth "frontal head" of the
temporal muscle, as described by Zenker.
Caput profundum masseteris
The so-called "deep head" of the masseter, the
Caput profundum masseteris of modern anatomi-
cal nomenclature, requires further explanation
(see ill. 19, right).
This muscle is not a single unit. Rather, it is com-
posed of two layers which, because they are
attached to each other in their front margins,
form an open "sac" at the back. The upper layer
originates with strong bundles of tendons at the
lower edge of the zygomatic bone, extending to
the temporal zygomatic suture, and is inserted in
the outer side of the mandible. The deep layer also
inserts in the outer side of the mandible and
extends to the zygomatic arch, whereby portions
of the fibers extend under it and are inserted in
the temporal fascia. A portion of the fibers also
extend to the lateral capsule and the lateral third
of the joint trochlea.
In Pernkopf's original terminology of topographic
anatomy, the two muscle plates have been termed
the Musculi zygomatico-mandibulares and are
thereby distinguished from the true masseter (see
ill. 20-23, pages. 72-73). The so-called deep head
of the masseter is also a term originating from the
new anatomical nomenclature. Nevertheless, this
muscle should be described as it was originally -
namely as an independent, two-headed muscle,
because its tasks are significantly different from those
of the true masseter. In a personal discussion with me,
Tom Wilkinson once described it as an "intelligent
tendon" between the upper and lower jaw.
Ill. 19: This sketch clearly shows the differentiation of vec-
tors within the heads of the masseter muscle.
Wilkinson, T.: personal communication
Pernkopf, E.: Atlas der topographischen und angewandten
Anatomie des Menschen. Platzer, W. (Hrsg.), Urban &
Schwarzenberg Verlag, München 1957
In Pernkopf's original terminology of topo-
graphic anatomy, the two muscle plates have
been termed the Musculi zygomatico-
mandibulares and are thereby distinguished
from the true masseter.
... an "intelligent tendon" between the upper
and lower jaw.
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R. Slavicek • The Masticatory Organ
72
Ill. 21: The picture shows that the mass of the superior head covers the main portion of the heads lying inferior to it.
Ill. 20: In this specimen, the proximity to the joint of the deep head is clearly seen.
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Structures
73
Ill. 23: The deep head itself consists of two heads, with somewhat different functions.
Ill. 22: Only after removal do the dimensions of the inferiorly located muscles become evident.
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R. Slavicek • The Masticatory Organ
74
The description "intelligent tendon" implies the
possibility that maintenance of variable translato-
ry distance can be programmed during function,
in order to maintain perfect functional translation,
appropriate to the bolus. The fibers inserting in
the condyle, the capsule and the disk are liable to
laterally contract the capsule and, thereby, the disk.
Again, the anatomist Pernkopf refers to both
heads as the zygomatic-mandibular muscles
(Caput superficialis et profundum), thereby dis-
tinguishing them from the true masseter.
Observations from Kunzl's dissertation, initiated
by myself, confirm and expand on this view.
In addition, they differ with regard to their vec-
tors as well as from the viewpoint of muscle phy-
siology and their innnervation. They provide sta-
bility for the mouth (intelligent tendon), and also
serve as an active, muscular "jumping sheet", sta-
bilizing the lateral open space. Contraction during
the closingphase of mastication induces a median
centralizing movement of the condyles (see ill. 24
and 25, left). In a new scientific study by Kunz et.
al., the insertion of fibers on the temporal fascia
has been given a new meaning and functional
interpretation.
Musculus pterygoideus lateralis 
caput superius
This muscle has been a subject of controversy over
the last two decades. Originally it was thought to
be the synergist of its counterpart, the inferior
head, and was thus described in the old anatomy
literature as the active "protractor" of the articular
disk. Electromyographic studies have proven,
however, that it normally works asynchronously
to the inferior head, which may be described as
the protractor of the mandible in symmetric or
asymmetric function (see ill. 26, p. 75). The supe-
rior head of the lateral pterygoid extends from its
origin at the sphenoid bone in the skull, posteri-
orly and inferiorly, and inserts in the median half
of the condyle, using the eminence as a hypo-
mochlion. Portions of the fibers also insert direct-
ly or indirectly on the articular capsule and on the
articular disk. The direct insertion in the articular
disk is more noticeable in fetal, infant and adoles-
cent articulations than in temporo-mandibular
joint specimens of older individuals. This may
have led to the numerous discussions in the last
few years, in which the direct insertion at the
Ill. 25: The distinct vector of the inferior head of the lateral
pterygoid muscle establishes this powerful muscle as the
"protractor" of the mandible. 
Ill. 24: This sketch of vectors is an attempt to illustrate the
differences. The posterior portions are functionally related to
the temporal fascia and the lateral portion of the joint.
Kunzl, G.: Makroskopische Untersuchungen der Kau-
muskulatur und ihre Beziehungen zum Kiefergelenksdiscus.
Dissertation a. d. Med. Fakultät Univ. Wien, 1994
Juniper, R. P.: Temporomandibular Joint Dysfunction: A
Theory Based upon Electromyographic Studies of the Lateral
Pterygoid Muscle. Br. J. Oral Maxillofac. Surg. Feb. 22 (1). P.
1–8, 1984
Juniper, R. P.: Electromyography of the Two Heads of
External Pterygoid Muscle via the Intra-Oral Route.
Electromyogr. Clin. Neurophysiol. Jan.–Feb. 23 (1–2). P.
21–33, 1983
Juniper, R. P.: The Superior Pterygoid Muscle? 
Br. J. Oral Surg. Jun. 19 (2). P. 121–8, 1981
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Structures
Ill. 26: In humans, the function of the superior head of the
lateral pterygoid muscle is asynchronous to that of the inferi-
or head and inserts in the condyle itself, as well as, in the
capsule and the articular disk.
articular disk has been disputed (comp. Juniper,
et. al.). The function of the muscle has been
described by several authors and has been repea-
tedly investigated by electromyography. Like the
deep head of the masseter, it is active during clos-
ing. It centers the condyle against the eminence
and is slightly active in a non-occlusally support-
ed "resting position", the so-called floating rest
position. This indicates its importance as an anti-
gravitational centering system (see ill. 27, p. 76).
Its connection to the capsule and, directly or indi-
rectly, to the disk, may function as a tight stabi-
lizer of these areas during rapid movement.
Hollmann once described the function of the
articular disk as an "active jumping sheet for the
condyle" (see ill. 28, p. 76).
The frontal head of the Musculus temporalis
In approximately 30% of the cases (comp.
Zenker, Kunzl), this portion of the temporal mus-
cle inserts between the masseter and the pterygoid
in the condylar process, the capsule and the disk.
It is also active during closing and is therefore
involved in "centering".
All muscles of the immanent musculature system
have an anteriorly oriented vector. Thus, contact
with the eminence is maintained through a nearly
"passive" state of readiness. One of the main res-
ponsibilities of this articular musculature appears to
be muscular centering of the mandible against the
cranium, made necessary by the evolutionary
change to the upright position. The numerous
fibers to the capsule may be interpreted as capsule
tensors. There is no doubt about the fact that mus-
cle fibers of the immanent musculature system also
extend to the articular disk. This is especially evi-
dent in the articulation of infants and adolescents
(see ill. 29-36, pages. 77-79). In the preparatory
access from above, the practicality of the cranio-
mandibular musculature becomes most evident.
The vectors establish the postural area of responsi-
bility, anteriorly against the eminence (see ill. 37-
42, pages. 80-81). From this viewpoint, the entire
ventral portion of the condylar process is a large
muscular cavity, offering possibilities of insertion
for muscles of the CMS (see ill. 43, p.82).
Electromyographically, the asynchronous functions
of both heads of the lateral pterygoid can be 
proven under physiological conditions (comp.
Tauber), (see ill. 44-48, pps. 82-83).
75
Wilkinson, T.: The Relationship between the Disc and
Lateral Pterygoid Muscle in the Human
Temporomandibular Joint. J. Prosthet. Dent. 60: 715, 1988
Wilkinson, T. M., Mahan, P. E., Gibbs, C. H., Mauderli, A.,
Bronnon, L. S.: Superior and Inferior Bellies of the Lateral
Pterygoid Muscle EMG Activity at Basic Jaw Positions. 
J. Prosth. Dent. 50: 710, 1983
Wilkinson, T., Chan, E. K.: The Anatomic Relationship of
the Insertion of the Superior Lateral Pterygoid Muscle to
the Articular Disc in the Temporomandibular Joint of
Human Cadavers. Aust. Dent. J. Aug. 34 (4): 315–22, 1989
Wilkinson, T., Crowley, C., Piehslinger, E., Wilson, D.,
Czerny, C.: Correlations between Anatomic and MRI
Sections of Human Cadaver Temporomandibular Joints in
the Coronal and Sagittal Planes. J. Orofac. Pain. 10 (3):
199–216, 1996
Fukuda, Y., Yoshida, K., Inoue, H., Suwa, F., Ohta, Y.: 
An Experimental Study on Inserting an EMG Electrode to
the Superior Head of the Human Lateral Pterygoid Muscle.
J. Jpn. Prosthodont. Soc. 34: 902, 1990
Yoshida, K., Fukuda, Y., Takahashi, R., Nishiura, K., Inoue, H.:
A Method for Insertion the EMG Elektrode into the
Superior Head of the Human Lateral Pterygoid Muscle. 
J. Jpn. Prosthodont. Soc. 36: 88, 1992
Meyenberg, K., Kubik, S., Palla, S.: Relationship of the
Muscles of Mastication to the Articular Disc of the
Temporomandibular Joint. Schweiz. Monatsschr. Zahnmed.
96: 815, 1986
Yoshida, K., Inoue, H.: An Electromyographic Study on the
Lateral Pterygoid Muscle during Mastication in Patients
with Internal Derangement of TMJ. J. Jpn. Prosthodont.
Soc. 36: 1261–1272, 1992
Dauber, W.: Die Nachbarschaftsbeziehungen des Discus 
articularis des Kiefergelenkes und ihre funktionelle
Deutung. Schweiz. Mschr. Zahnmed. 97: 427, 1987
www.ajlobby.com
R. Slavicek • The Masticatory Organ
76
Ill. 27: An electromyographic recording in a non-occlusally supported, so-called floating rest, shows the activity of the superior head,
establishing its function as a postural muscle. When active, it holds the condyle against the disk, and disk to the eminence.
Ill. 28: A symbolic photograph showing the "jumping-sheet" nature (Hollmann) of the system.
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Structures
77
Ill. 31: This picture makes it clear that the muscle bundles are in direct contact with the capsular collagen tissue and with the mar-
ginal region of the disk.
Ill. 29: This sketch makes it clear that the superior head may
also consist of several heads , or if you will, one head with
two different anatomical insertions (Wilkinson).
Ill. 30: The joint trochlea of a newborn shows the distinct attach-
ments of muscles to the disk. The main portion of the superior
head, however, inserts in the condylar process.
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R. Slavicek • The Masticatory Organ
78
Ill. 32, 33: Direct insertion is seen under strong magnification.
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Structures
79
Ill. 34: In the polarization
microscope, the brightly lit
musculature can be clearly dis-
tinguished from the slightly
undulating structure of colla-
gen fibers. 
Ill.35: Noticeable, in this
purely sagittally oriented sec-
tion, is the larger quantity of
"transversally intersected"
bundles, relative to the anteri-
orly arranged bundles, which
cannot possibly correspond to
the sagittal vector of the
pterygoid muscle.
Ill. 36: In a view created by a
lateral access, it is difficult to
display the spatial arrange-
ment of muscles according to
their vectors. Green: portions
of the deep head of the mas-
seter muscle.
White: the disk. 
Red: the superior head of the
lateral pterygoid muscle.
Yellow: the head of the tempo-
ral muscle.
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R. Slavicek • The Masticatory Organ
80
Ill. 37: The picture shows the entry from
the middle cranial fossa.
Ill. 38: A representation of the
entry area.
Ill. 39: Removal of the bony
covering.
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Structures
81
Ill. 40: The morphology of the
structures from cranial view. 
White: the articular disk.
Green: the deep masseter. 
Red: the superior head of the
pterygoid muscle. 
Black: the masseter nerve.
Ill. 41: This picture shows a
specimen with a clearly distin-
guishable temporal portion
(yellow).
Ill. 42: A representation of
vectors with a receding tempo-
ralis.
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R. Slavicek • The Masticatory Organ
82
Ill. 43: This spatial representation of a computerized tomograph establishes
the anterior portions of the joint cavity as actual muscular fovea.
Ill. 45: If the test subject bites onto the incisal edges, simultaneous activity in the midle temporal muscle and in the inferior head of
the pterygoid muscle is seen.
Ill. 44: Only the inferior heads of the lateral pterygoid muscles are active when the mouth remains continuously open.
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Structures
83
Ill. 46: A comparison of a
functionally normal test sub-
ject with a functionally
abnormal patient shows that
in the former, the tap-open
action proceeds asynchro-
nously in the superior and
inferior heads, but synchro-
nously in the abnormal
patient.
Ill. 47: This is also the case
in rapid execution.
Ill. 48: In a patient with a
strong functional disorder,
permanent activity is seen in
both heads of the lateral
pterygoid muscle.
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The synovial apparatus
The predominantly translatory function of
mandibular movement requires maximum fric-
tion-free gliding of the condyle-disk assembly on
the eminence. Because of the vector of the inferi-
or head of the lateral pterygoid, a positive anteri-
orly directed inter-capsular pressure results from
protrusive movement, whereby synovial fluid is
expelled. In the recovery phase, a low-pressure si-
tuation occurs, i.e., a potential vacuum, which
causes the synovia to be sucked back into the
complex. This is the physiological basis for joint
metabolism (see ill. 49 and 50, left). In all cases of
functional disturbances of the condyle-disk assem-
bly, joint metabolism is jeopardized, due to an
innate absence of a vascular supply system.
Extended ligamentous attachments
The mandible and the hyoid in Homo sapiens are
ligamentously self-centering, fixed to (or rather
suspended from) the skull by three ligaments (see
ill. 51, p.85). Because of their course and their
detailed fiber distribution, they are ideally suited
for centering the mandible "non-muscularly,
involving minimal activity on the part of the pos-
tural musculature. The following ligaments exist
(see ill. 52-57, pages. 87-88):
• Ligamentum sphenomandibulare
• Ligamentum stylomandibulare
• Ligamentum stylohyoideum
• Ligamentum pterygospinale
Ligamentum sphenomandibulare
This ligament extends from the angular process of
the sphenoid to the lingula of the mandible in the
entry area of the bundle of mandibular neural
fibers, and lies between the inferior head of the
lateral pterygoid and the medial pterygoid.
Practically, it has approximately the same vector
as these muscles and approximates their passive
extended position. As a ligament, it holds the
ascending branch between the two muscles and
centers the mandible simultaneously to the mid-
dle and anteriorly against the eminence, without
having to utilize the strength of the two mastica-
tory muscles.
84
R. Slavicek • The Masticatory Organ
Ill. 49: An average protrusive movement creates positive out-
ward pressure to the vector of the inferior head of the lateral
pterygoid muscle, causing synovia to be expelled.
Ill. 50: An incursive movement reduces the pressure, and
synovia is sucked in.
• Ligamentum sphenomandibulare
• Ligamentum stylomandibulare
• Ligamentum stylohyoideum
• Ligamentum pterygospinale
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Structures
85
Ill. 51: A clear display of the cranio-mandibular suspension by a self-centering ligamentary apparatus (posterior view).
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R. Slavicek • The Masticatory Organ
86
Platzer, W., Pomaroli, A.: personal communication
Platzer, W., Pomaroli, A.: Zur Anatomie der Kiefergelenke.
Fortschr. Kiefer-Gesichtschir., 25: 1–2, 1980
Rocabado, M.: Physical Therapy for the Postsurgical TMJ 
Patient. J. Craniomandib. Disord., 3 (2): 75–82, 1989
Rocabado, M.: The Importance of Soft Tissue Mechanics in 
Stability and Instability of the Cervical Spine: A
Functional Diagnosis for Treatment Planning. Cranio., Apr.
5 (2): 130–8, 1987
Rocabado, M.: Biomechanical Relationship of the Cranial, 
Cervical and Hyoid Regions. J. Craniomandibul. Pract., 
Jun.–Aug. 1 (3): 61–6, 1983
Ligamentum stylomandibulare
It extends from the styloid process to the inner
side of the angle of mandible, where it expands
fan-like, and meshes in the fascia of the medial
pterygoid. This fan-shaped structure displays details
that are histomorphologically interesting regard-
ing cross-meshing, which afford the ligament the
ability of active recovery from the medio-eccentric
position. 
Ligamentum stylohyoideum
This ligament also extends, along with the stylo-
mandibular ligament, from the styloid internally,
anteriorly and inferiorly, and subsequently also
meshes with intermediate fibers. Here again, the
result is tension within the intermediate fibers
during eccentric movement to the mediotrusive
side. Median muscular movement is followed by a
"ligamentary" return of the mandible to the mid-
dle (comp. Platzer). These ligaments are impor-
tant from the viewpoint of both function and dys-
function, and must be given due consideration
during diagnostic procedures.
Ligamentum pterygospinale
An additional aspect of the significance of the lig-
amentary structures is seen in the pterygospinal
ligament. This short but powerful attachment
might have been involved in ontogenetic vertical-
ization in the transfer of tension from the sphe-
nooccipital syndesmosis in the viscerocranium. Its
insertion in the posterior margin of the pterygoid
process would be suitable for effecting an indirect
transfer of tension onto the vomer bone during
the rotation and expansion phase in the ontoge-
netic process towards bipedal locomotion, and a
simultaneous expansion in breadth of the neuro-
cranium. This influence on the action of the
vomer might be important for Dr. Sato's growth
prognosis, which I will refer to later in the discus-
sion of cranial structures.
The so-called "alpha" ligament
Rocabado postulates a ligamentary loop, which
connects the hyoid and the cervical spine. From
this viewpoint, alterations in flexion of the cervi-
cal spine have a direct effect on the position of the
hyoid and thereby also on the position of the
mandible. In Rocabado's diagnostics, this liga-
ment’s status is considered highly significant and
influences his therapeutic approach.
Details of cross-meshing, which affords the
ligament the ability of active recovery from
the medio-eccentric position.
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Structures
87
Ill. 52: The stylohyoid ligament and the stylomandibular ligament from a posterior view.
Ill. 54: This illustration shows the pterygomandibular liga-
ment and the stylomandibular ligament from a medial view. 
Ill. 53: The temporo-mandibular ligament, the stylomandibu-
lar ligament and the stylohyoid ligament from a lateral view.
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88
Ill. 57: Tension and relaxation in eccentric movement.
Ill. 55, 56: This illustration is an attempt to illustrate the detailed structure of the stylomandibular ligament on the inner side of the
mandible.
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Structures
89
Summary
H. Sicher's description of the temporo-mandibular
joint as a synovial, gliding joint with a moveable
socket is undisputed. The joint capsule is spacious,
allowing for a high degree of translation. The
temporo-mandibular ligament is a practical rein-
forcement of the capsule, and serves as a diverter
in cases of rapid retral movement towards the cra-
nium. Strong loads are placed on the temporo-
mandibular ligament in cases of high vertical loss
(anodontism, sunken total prosthesis), necessita-
ting a forward shift of the mandible. It influences
the course of mandibular marginal movements in
Posselt's scheme.
The retral vascular pad offers protection against
trauma directed posteriorly, but also functions as
an elastic, hydrodynamic buttress during mastica-
tion and speech and as a three-dimensional place-
ment mechanism for interference-free recovery
into the normal occlusal position without sub-
stantial guidance from muscles.
The musculature of the CMS centers the condyle
against the articular eminence. This immanent
musculature system is active in non-occlusally
supported maintenance of functional readiness
(the "floating rest"), and in activities involving the
closing muscles.
It is not active in eccentric dynamics in function-
ally healthy individuals.
The so-called "deep head" (actually two heads) of
the masseter (Musculus zygomaticomandibulare)
functions both as a positioning mechanism for the
vertical distance of occlusion and as a lateral bor-
der (jumping sheet) for condylar movement. Its
contraction at the end of the mastication loop cen-
ters the mandible from a lateral position as a mus-
cular "jumping sheet" in a medial direction ("in-
shift"). The closing muscles (adductors) move the
mandible cranially and anteriorly to reach the
occlusal position. In this setting, the muscles of
the CMS take over the fine tuning of articular
structures and centering to the eminence.
During protrusive translation, a positive pressure
is created in the synovial joint and synovial fluid is
expelled. When the retractor muscles pull the
mandible back from the protruded position, the
pressure is reduced and the synovial fluid is
sucked in. Joint metabolism is maintained
through these movements.
The human temporo-mandibular joints have
assumed responsibility for a significantly
expanded functional area. They are not joints
in the true sense of the word, but rather con-
stitute a new system in conjunction with
other structures. The system may be termed
the cranio-mandibular system or CMS.
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The neuromuscular system adds dynamics to the
remaining structures of the masticatory organ. It
assumes the responsibility of determining func-
tionally appropriate processes in so-called move-
ment patterns. The required information is pro-
vided by proprioceptive signals from other struc-
tures and internal system controls.
The previously described modifications and exten-
sions of the functional range in the human masti-
catory organ apply to a great extent to muscles, in
which there are also considerable overlapping
areas of responsibility to be mastered. Two illus-
trative examples are the functions of head posture
and speech. The human, standing or sitting
upright, carries or "balances" the head on two re-
latively small articular surfaces of the atlanto-
occipital joint between the cranium and cervical
spine. This task is performed in humans in a com-
plicated way, through an evolutionarily practical
restructuring of the muscle groups. Posteriorly,
the muscles are able to achieve a kind of "flexible"
dynamic balance by means of the widely project-
ing atlas and the phylogenetically and ontogene-
tically prepared cervical spine, in order to afford
the receptor systems, the eyes and ears, optimal
contact with the environment, whereby the
mobile pectoral girdle has a stabilizing effect. The
eyes will always strive to seek a horizontal neutral
position with the horizon. Ventrally, postural con-
trol is anchored in the sternum and clavicle and
extends to the mandible by means of the move-
able hyoid.
90
R. Slavicek • The Masticatory Organ
The Neuromuscular
System (NMS) -
muscles of the 
masticatory organ
The neuromuscular system adds dynamics to
the remaining structures of the masticatory
organ. 
The human, standing or sitting upright, car-
ries or "balances" the head on two relatively
small articular surfaces of the atlanto-occipital
joint between the cranium and cervical spine. 
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The mandible itself is, in turn, muscularly
attached to the cranium. This interrupted and
therefore indirect attachment serves to maintain
postural balance, but is also required to perform
other important functional tasks. One of these is
communicative speech, the "transmitter" for
establishing contact with others in the environ-
ment. Dynamic head posture and speech, a high-
precision motoric feat, need to be carried out
simultaneously, and are a small example of the
extensive additional responsibilities that the neu-
romuscular system must carry out as a result of
man's evolution to Homo. Naturally, the condi-
tion of the "receiving system", the sensory organs,
is of great importance to the muscles. Optical or
acoustic stimuli are especially important for the
mobile overall posture of the head (see ill. 58-66,
p. 92-93). The NMS requires paramount consid-
eration in the diagnostics of the functions and dys-
functions of the masticatory organ, as the adapta-
tion and compensation mechanisms for maintain-
ing undisturbed functionality are mainly per-
formed here. For this reason, problems in the
NMS are disorders that are recognized by the
patient and cause him/her to report for regular
check-ups or for physiotherapy. Often, these prob-
lems affect the cervical spine and overlap into
functional areas of the stomatognathic system. It
would be a great error in judgment to regard
these problems only from the viewpoint of the
complex joint mechanics of the cervical spine and
the atlanto-occipital attachment and not from the
standpoint of the musculature. In the sequence of
examining the functional state of the masticatory
organ, a careful, standardized investigation of the
NMS must be given first priority. This is not pos-
sible, however, without basic knowledge of the
morphology of the muscular system. The mor-
phological concept mentioned here is meant to
denote its original meaning, namely the "form
and dynamics of structural units". The NMS of
the masticatory organ may in no way be viewed in
isolation during the examination. Associations
with problems of overall physical posture must be
considered, especially those between special groups
of the NMS and the temporo-mandibular joints. In
addition, other areas are also very important e.g.,
it is essential to study the overall functions of the
masticatory organ. Knowledge of the anatomical
makeup and functions of the NMS is a prerequi-
site for understanding function and dysfunction.
91
Structures - the Neuromuscular System
One of these is communicative speech, the
"transmitter" for establishing contact with
others in the environment. 
Naturally, the condition of the "receiving sys-
tem", the sensory organs, is of great impor-
tance to the muscles. 
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R. Slavicek • The Masticatory Organ
92
Ill. 58-66: The human head with its face is distinguished by the sensory organs.
Mobility of the head is a precondition for the receptor systems of the eyes, ears
and nose. Tilscher describes the cervical spine as an additional sensory organ. The
masticatory organ, head and neck are a functional unit of the bipedal human
being.
Ill. 60Ill. 59
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Structures - the Neuromuscular System
93
Ill. 61 Ill. 62
Ill. 63 Ill. 64
Ill. 65 Ill. 66of the atlanto-occipital joints and the cervical spine 343
Analysis of mandibular movement 343
The clinical examination of mandibular movement - manipulative techniques 345
Preliminary neurological findings 345
Clinical diagnostics of occlusion and articulation (dental status) 349
The periodontal examination 350
Clinical functional analysis with the aid of instrumental devices 352
Condylography 352
The principle of joint track recording, relative to the hinge axis 359
Mechanical graphic recording of joint movement 359
Electronic condylography: procedures for using the devices 360
Diagnostics using clinical recordings of mandibular movement 372
Creating standards of evaluation 373
Systematic evaluation of the eight basic recordingsli 373
Introduction to practical descriptive diagnostics 374
Terminology of quantification 374
Quantity 377
Limitation 377
Acute inflammation in the CMS 378
Acute inflammation outside of the CMS 378
Acute trauma 378
Effects of trauma (ankylosis) 379
Adhesions 379
Pseudo-adhesions (synovial problems) 380
Joint capsule (scars, systemic disease) 380
Problems of the ligamentary apparatus of the CMS 380
Functional problems of the articular disk 381
Luxation to anterior 382
Mechanical hindrances 382
Degenerative changes in the joint (arthrosis) 383
Problems of the facial soft tissue 383
Limitation of movement in the mandibular joint 383
Pain and muscular inhibition 383
Ligamentary problems in the CMS 384
Avoidance mechanisms 388
Discussion of limitations 391
Hypermobility 391
The quality of the recording 396
The characteristics of the recording 396
Side comparisons (symmetry) of the recordings 397
Temporal course of the recordings 397
Speed phenomena of the recordings 398
So-called joint noisei 398
Causes of joint noise 399
Reduction cracking and luxation cracking (according to Farrar) 399
So-called reciprocal cracking in the six basic movements 400
Protrusion 400
Retrusion 401
R. Slavicek • The Masticatory Organ
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Contents
9
Mediotrusion 401
Medioretrusion 401
Opening 401
Closing 404
Guided movements 404
Pressure directed to cranial 404
Luxation-reduction anterior cracking 405
Patho-morphological cracking 406
Ligamentary cracking 408
Synovial noise 408
Observing function 409
Masticatione 409
Speech 410
Stress management 413
Deglutition 413
Conclusions 415
Instrumental functional analysis with the Cadiax Compact 416
Instrumental functional analysis 423
Instrumental Functional Analysis- a definition 424
Procedures (list of work procedures 424
Creating exact jaw models 425
Verification of the retral physiological position
(or pathophysiological position) of the mandibular joints 429
Open questions and discussions 434
Generating a coordinate-system appropriate to the reference 
position (appropriate to the joint) 436
Attaching the jaw models in the articulator 437
Analysis of mandibular position 437
Analysis of tooth position 442
Analysis of the dynamics of mandibular movement 442
Additional diagnostics 447
Lateral X-ray 447
Procedure for obtaining a lateral X-ray 448
Patient instructions 449
Fixing and adjusting the patient in the head-fixing device; 
removal of ear plugs; taking the image 449
Developing the film and control (not applicable for digital imaging) 450
Tracing 450
Evaluation of the lateral X-ray 450
Evaluation of the skeleton 451
Assessment of the vertical 454
Dental analysis and the assessment of the occlusal plane 455
Esthetic evaluation and assessment 456
Static diagnostic analysis 456
Dynamic (functional) analysis 456
The introduction of front tooth control into the lateral X-ray 457
Radiological and imaging procedures 458
Panoramic overview recording and other slice techniques 458
Lateral-transcranial joint X-rays 459
Mandibular joint tomography 459
Computed tomography of mandibular joints 459
Arthrography 460
Magnet resonance imaging of the mandibular joints 460
Additional diagnostic measures in the articulator 461
Diagnostic equilibration 461
Procedures 461
Diagnostic wax-up 462
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10
Orthodontic and surgical set-up 462
Summing up ideas about diagnostics and diagnosis 463
The masticatory organ as a feedback control mechanism - the human being 
as a feedback control mechanism 463
Principles of correlation diagnostics 465
Streamlining the results of diagnostic procedures 465
The form of a correlation scheme 465
Entering data into a correlation scheme 466
Evaluation of the validity of individual findings 466
Arranging individual findings according to their significance 466
Synopsis and diagnosis (verbal summary) 466
Determining the therapeutic value 467
Planning therapy 467
Implementing the therapy and control 467
Setting up a maintenance program 468
Thoughts on the current situation regarding the application of diagnostic measures 469
Chapter 5: THERAPY 471
A few thoughts regarding the treatment of functional disorders of the masticatory organ 472
Symptomatic therapy for acute pain 473
Causal initial therapy of the dysfunctional masticatory organ 474
Therapy of predominantly muscular causes 474
Therapy of causes predominantly located in the joint area 474
Therapy of predominantly occlusal causes 475
Therapy of predominantly psychological causes 475
Therapy of predominantly neural causes 476
The treatment of somatic causes or systemic diseases with involvement 
of the masticatory organ 476
Therapy in cases of predominantly environmental factors 477
Capitolo 6: THE DYNAMIC FUNCTIONAL ANATOMY OF 
CRANIOFACIAL COMPLEX AND ITS RELATION TO 
THE ARTICULATION OF THE DENTITIONS – S. SATO 482
Introduction 484
Evolutionary aspects of craniofacial bones 486
Craniofacial bone connection 487
Sphenoid bone 487
Occipital bone 488
Vomer bone 488
Temporal bone 488
Craniofacial bone dynamicss 490
Occiput-spheno-maxillary complex with the vomer bone 491
Maxillary bone growth according to the dynamics of the cranial base 492
Temporo-mandibular complex 494
The importance of the function of occlusion for mandibular growth 495
Craniofacial growth and development with special focus on the occlusal plane 496
Cephalometric evaluation of the denture frame (denture frame analysis) 498
Implications for dental practice - Developmental mechanism of growth abnormality 502
References 514
Concluding remarks 516
Bibliography and literature for further study 522
Glossary 535
Acknowledgements 542
R. Slavicek • The Masticatory Organ
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Introduction
11
Functions and 
dysfunctions of the 
so-called 
"masticatory organ"
The human masticatory organ is unique in its struc-
ture and functions. I open with this simple state-
ment because it reflects my deepest convictions and
motivation, based on my knowledge and experi-
ences.
In an extremely short and therefore dramatic peri-
od of evolution, the simple primate masticatory
organ developed into a complicated and fascinating
multi-functional system.
In fact, the term "masticatory organ" is inappropri-
ate, as the function which gives the name, is cer-
tainly not its most important one. Recognizing and
understanding the phylogeny and characteristic
changes to Homo sapiens sapiens is important in
order to properly appreciate the brilliant variety as
well as vulnerability of this fascinating organ.
Our knowledge of the repetitive phylogenic steps
during ontogenesis highlights the problematic areas
brought about by overlapping new functional areas
and the resultant susceptibility to impairment. All
epidemiological studies in adolescents have demon-
strated temporary "crashes" to signs and symptoms
of dysfunction. This is because form is constantly
and rapidly changing, and function must continu-
ally adapt during development.
One of the most important ideological and concep-
tual errors in dentistry is based on the dogmatic
declaration of a fictitious goal, namely an ideal eug-
nathia, which is exalted to the Holy Grail of dental
medicine. This dangerous stigma, branded in the
young dental student's brain, influences a dentistwww.ajlobby.com
The morphology and responsibilities of the mus-
culature are described in the following section.
Knowledge of these aspects is necessary in order
to understand the dynamic processes of mandibu-
lar movements and the functional responsibilities
associated with them. Dynamic registration of
mandibular movement, which a part of this book
is devoted to, is not at all simple (and is almost
derogatorily referred to as "jaw-tracking" in cur-
rent jargon) but indicates, in complex form, the
relationship between muscle and joint.
Morphology, functions, innervation and basic vec-
tor principles must be described in detail, as this
information is needed for sufficient comprehen-
sion of the subject. The central functions overlap
other functional areas to a great extent. Within
the scope of dental medicine, it is necessary to
have profound knowledge of these crucial areas.
The musculature of the 
masticatory organ
• Innervation by the Nervus trigeminus 
V/3, portio minor
• Musculus temporalis
• Musculus masseter
• Musculus pterygoideus medialis
• Musculus pterygoideus lateralis
• (Musculus tensor tympani)
• Innervation by the Nervus facialis 
• Musculus biventer, venter mastoideus
• Musculus stylohyoideus
• (Musculus stapedius) 
• Musculus levator veli palatini
• Musculus uvulae
• The mimic musculature
• Musculi epicranii
• Musculus depressor glabellae – muscles
around the palpebral fissure 
• Musculus corrugator glabellae
94
R. Slavicek • The Masticatory Organ
Dynamic registration of mandibular move-
ment, which a part of this book is devoted to,
is not at all simple (and is almost derogatorily
referred to as "jaw-tracking" in current jar-
gon) but indicates, in complex form, the rela-
tionship between muscle and joint. 
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• Musculus orbicularis oculi
• Platysma
• Musculus quadratus labii inferius
• Musculus mentalis
• Musculus triangularis
• Musculus risorius
• Musculus zygomaticus major 
• Musculus zygomaticus minor
• Musculus infraorbitalis
• Musculus angularis
• Musculus caninus
• Musculus buccinator
• Musculus orbicularis oris
• Musculus nasalis - muscle on the 
auditory aperture
• Musculus auricularis temporalis
• Musculus auricularis nuchalis
• Innervation by Nervi glossopharyngicus
and vagus (muscle in the rhomboid fossa)
• Musculus tensor veli palatini
• Muscles of the pharynx
• Innervation by Nervus vagus (Nucleus
ambiguus, Nucleus laryngicus in the
rhomboid fossa)
• Muscles of the larynx
• Innervation by Nervus accessorius
(muscle core in the cervical cord)
• Musculus sternocleidomastoideus
• Musculus trapezius
• Innervation by Nervus hypoglossus
(muscle core in the rhomboid fossa)
• Musculus geniohyoideus
• Musculi linguae (tongue)
95
Structures - the Neuromuscular System
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R. Slavicek • The Masticatory Organ
Musculus temporalis
The temporal muscle (see ill. 67, left) is a muscle
plate resembling the sector of a circle, filling the
temporal fossa and covering the bone forming the
temporal plane with its field of insertion. In the
skull of a newborn, it extends up to the superior
border of the squamous part of the temporal bone.
With the eruption of teeth, its insertion is shifted
higher on the lateral surface of the cranium.
Along with its rough fibers it forms the two tem-
poral lines on the lateral wall of the skull. Its vari-
able and individual origin in bone extends forward
to the zygomatic process of the frontal bone,
backwards behind the auricle to the supramastoid
ridge and down to the infratemporal ridge. The
temporal fascia serves as its origin. The fibers of
the temporal muscle converge to the inferior exit
of the temporal fossa. The outer side of the mus-
cle indicates an individually proportional tendon
arrangement. The muscle forms a very strong ter-
minal tendon, which extends under the zygoma-
tic arch and inserts in the coronoid process of 
the mandible. The most anterior portions of the
muscle frequently (30%) form a frontal section
(comp. Zenker), which is inserted in both, the
coronoid and (with receding fibers) into the
condylar process. The functional details of this
variation are described in the section dealing with
the CMS musculature.
Functions of the Musculus temporalis
It is an adductor, retractor, laterorotator and, in a
case of a frontal head, a muscle of the CMS, with
the task of centering the condyle against the emi-
nence.
The temporal muscle is assigned to the group of
adductors and raises the mandible in closing
movement. Because of its differential fibrous
arrangement and its slightly anteriorly conver-
ging overall vector, it is not only an adductor but
also a retractor, and can rotate the mandible
somewhat laterally. Its posterior portions, which
extend anteriorly almost horizontally, induce
retraction of the protruded lower jaw. This part of
the muscle is an antagonist of the inferior head of
the lateral pterygoid muscle.
As mentioned earlier, approximately one third of
all humans have a frontal head with receding
96
Ill. 67: The converging fibers insert in the coronoid process of
the mandible.
Zenker, W.: Über die mediale Portion des M. temporalis und
deren Funktion. Österr. Zschr. f. Stomatol., 51: 550–554, 1954
Zenker, W., Zenker, A.: Zur funktionellen Anatomie des 
M. temporalis. Dt. Zahn-, Mund- und Kieferheilkunde, 24:
368–375, 1956
It is an adductor, retractor, laterorotator and,
in a case of a frontal head, a muscle of the
CMS, with the task of centering the condyle
against the eminence.
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fibers leading to the condyle, which is involved in
the immanent musculature system of the CMS.
Its insertion in the coronoid process (processus
muscularis), which it encompasses in a variable
fashion both directly and with tendons, permits
precise control of intercuspation (see ill. 68, right).
Innervation of the Musculus temporalis
V/3 pars. mot., Nn. temporalis prof. 2-3
Musculus masseter
The true masseter muscle (ill. 69, right) is a some-
what rectangular, powerful muscle plate, extend-
ing obliquely from inferior-posterior to anterior-
superior, attaching the mandible to the cranium.
Underneath are two additional flat muscle plates,
which are combined in the accepted modern ter-
minology and designated the deep head of the
masseter muscle. No distinction is made between
the two; together they are known as the deep
head. As the two muscles cannot be assigned to
the masseter, either with regard to their vector,
function or characteristics, from a diagnostic
standpoint they must be distinguished from the
true masseter in the stomatognathic system.
They consist of two layers hanging together in the
anterior margin and forming a sac, which opens at
the back. The surface layer originates in the infe-
rior border of the zygomatic bone in powerful
bundles of tendons, extends back to the temporal
zygomatic suture and inserts in the process of
mandible. The inferior layer also inserts in the
outer side of the mandible and extends to the
arcus zygomaticus, whereby, parts of the fibers
extend underneath and are inserted in the tempo-
ral fascia. However, some of the fibers also extend
medially to the lateral pole of the condylar
process.
In the original terminology of topographic anato-
my, Pernkopf termed these two muscle plates the
Musculi zygomatico mandibulares, thereby distin-
guishing them from the true masseter.
97
Structures - the Neuromuscular System
Ill. 69: In the above illustration, one mainly sees the superior
head, with its vector progressing to anterior-superiorly. The
so-called deep head is detectable very close to the joint and
can be distinguished by its fiber arrangement.
Pernkopf, E.: Atlas der topographischen und angewandten
Anatomie des Menschen. Platzer, W. (Hrsg.), Urban &
Schwarzenberg Verlag, München 1957
Ill. 68: The vectors of the muscle that executes closing and
retraction functions. In a bald individual, the sequence of
contraction during mastication can be seen very clearly.
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Functions of the Musculus masseter
Itis an adductor, laterotractor and laterorotator.
The masseter is the "lifter" (adductor) of the lower
jaw (see ill. 70, left). Its anterior-superior vector
centers the mandible and thereby the condylar
process against the articular eminence of the tem-
poral bone. In conjunction with the medial ptery-
goid (comp. Dauber) it forms a functional unit
known as the pterygoid-masseter loop. Vector
analysis shows that, in addition to the closing
function, this unit also has the ability to shift the
mandible laterally and to rotate it a little.
Innervation of the Musculus masseter
Innervation is provided by the masseteric nerve
(V/3 pars motorica). The masseteric nerve extends
from anterior to the condyloid process of
mandible, laterally and posteriorly to the mas-
seter. It belongs to the motoric portion of the
trigeminus nerve.
The so-called "deep head" of the masseter and its
functions will be discussed in the description of
the immanent musculature system of the CMS
(see ill. 71, left).
Musculus pterygoideus medialis
This muscle (see ill. 72, p. 99) is a synergist to the
masseter, located on the inner side of the
mandible and linked with the masseter through a
strip of tendon, so that together they form a
strong loop around the angle of the mandible.
The loop encompasses not only the posterior por-
tion of the horizontal branch of the mandible but,
like a sac, also the posterior border of the ascend-
ing branch. The medial pterygoid is at approxi-
mately the same level as the masseter, only half as
wide but twice as thick and, in contrast to the
sagittal arrangement of the masseter, is located
somewhat towards the front. Its short but power-
ful traction originates in the pterygoid fossa and
the pyramidal process of the palatal bone and
pulls obliquely posteriorly, inferiorly and laterally,
finally inserting in the inner side of the angle of
the mandible and the pterygoid tuberosity. Its
fibers often intertwine with those of the inferior
head of the lateral pterygoid.
98
R. Slavicek • The Masticatory Organ
Dauber, W.: Die Nachbarschaftsbeziehungen des Discus 
articularis des Kiefergelenkes und ihre funktionelle Deutung.
Schweiz. Mschr. Zahnmed., 97: 427, 1987
Ill. 71: Illustrating the vector is an attempt to show the vari-
ous tasks of the deep heads and their significance for the
CMS. In protrusion, the muscle plate secures the joint head
in a lateral direction.
Ill. 70: The vector of the superior head shows the direction of
closing and centering movements.
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Functions of the Musculus 
pterygoideus medialis
It is an adductor and mediotractor. The medial
pterygoid is the powerful closer (adductor) of the
mandible. It belongs to the group of jaw eleva-
tors, along with the masseter and temporalis 
muscles. Unilaterally innervated, it is a powerful
mediotractor that is frequently involved in the
occurrence of bruxism. Its vector extends from
inferior-posterior-external to anterior-internal-
superior (see ill. 73, right).
Innervation is supplied from V/3 pars. mot., by
the medial pterygoid nerve.
Musculus pterygoideus lateralis caput
inferius
This powerful muscle (see ill. 74, p. 100) is shaped
like an obliquely lying pyramid, approximately 
5 cm in length, with a base measuring approxi-
mately 4x2 cm. The muscle lies in the infratem-
poral fossa of the sphenoid and originates in the
outer surface of the wide lateral lamina of the
pterygoid process and in the infratemporal fascia
of the maxilla. In terms of function it is to be
strictly distinguished in humans from the superi-
or head of the same name. The muscle inserts in
the pterygoid fovea on the anterior side of the
condylar process. At the site of origin its fibers fre-
quently interweave with those of the medial
pterygoid.
Functions of the Musculus 
pterygoideus lateralis caput inferius
It is a protractor and, in case of unilateral action,
a mediotractor. The vector of this muscle (see ill.
75, p. 100) is nearly horizontal; its origin is ante-
rior-median. Its insertion in the condylar process
lies posteriorly and laterally, so its fibers extend
from the insertion anteriorly and internally. It is a
protractor of the mandible and initiates every
muscular function of the masticatory organ, from
the relative or absolute retral position of the
mandible, in resting position.
Because of its horizontal-oblique vector, it is an
efficient mediotractor with unilateral innervation .
99
Structures - the Neuromuscular System
Ill. 73: The vector of the medial pterygoid muscle is directed
superiorly, anteriorly and, above all, inward.
Ill. 72: The morphological units of the medial pterygoid
muscle with the masseter and the inferior head of the lateral
pterygoid muscle are illustrated here. The sac-like enveloping
of the angle of the mandible as a loop is clearly seen. (person-
al communication Prof. Dauber)
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R. Slavicek • The Masticatory Organ
100
Ill. 74: The inferior head of the lateral pterygoid muscle and the medial
pterygoid muscle are functional "partners". The superior head, also shown
(green), is assigned to the CMS-specific musculature.
Ill. 76: The superior head, active in closing, centers the
condyle against the eminence.
Ill. 75: This illustration of the vector of the inferior head
makes its protrusive function clear.
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In protrusion, the vector causes positive physio-
logical pressure in the joint during the preliminary
gliding movement against the articular eminence
(see ill 76, p. 100), and is angled obliquely in the
opposite direction. The increase in pressure causes
synovial fluid to be expelled. This function is
important for joint metabolism. The function of
the superior head is independent of the inferior head.
The Musculus pterygoideus lateralis caput inferius
is innervated from V/3 pars. mot.
Musculus mylohyoideus
This muscle (see ill. 77, right) forms a parallel-
fibered plate, which originates with short, tendi-
nous fibers on both sides along the mylohyoid line
in the inner side of the mandible and extends pos-
teriorly to the medial pterygoid. The right and
left muscles converge to a raphe, which extends
from the symphysis of the chin to the body of the
hyoid. The posterior margin of the muscle inserts
in the body of the hyoid. At approximately half
the distance the muscle forms a gap, which allows
for vessels and also a process of the sub-mandibu-
lar gland to pass through. It forms a so-called oris
diaphragm.
Functions of the Musculus mylohyoideus
This muscle is responsible for an "active floor of
the mouth". Both mylohyoids support the tongue
like an "adjustable jumping sheet" and allow it to
function. In deglutition, they raise the hyoid, with
the dental arches supporting the mandible against
the skull. However, if the hyoid is isometrically
stabilized downwards, these muscles have the
potential to depress the mandible. The floor of the
mouth is most significantly involved in the func-
tion of speech, as the high-precision motor move-
ments of the tongue require total functional coor-
dination with the floor of the mouth.
Innervation of the Musculus mylohyoideus
From V/3 pars mot. by a branch of the inferior
alveolar nerve. In the floor of the oral cavity the
so-called trigeminus musculature is layered
beneath the tongue's hypoglossus musculature.
101
Structures - the Neuromuscular System
Ill. 77: The mylohyoid muscle forms the flexible floor of the
mouth.
The Musculus pterygoideus lateralis caput
inferius is innervated from V/3 pars. mot.
This muscle is responsible for an "active floor
of the mouth".
In the floor of the oral cavity the so-called
trigeminus musculature is layered beneath the
tongue's hypoglossus musculature.
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R. Slavicek • The Masticatory Organ
102
Ill. 80: The posterior belly originates in the mastoid notch of
the temporal bone, inferior to the longissimus muscle and the
splenius capitis muscle. Note the open angle between the sty-
lohyoid muscle and the posterior belly of the digastric muscle.
Here, the liftersand retractors of the hyoid are clearly recog-
nizable and distinguishable in terms of function.
Ill. 79: The anterior belly, which inserts in the inner men-
tosymphysis, is supplied from the motor part of the trigemi-
nus nerve.
Ill. 78: This illustration shows the origin, progress and insertion
of this complex muscle, which is involved in nearly all functions.
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Musculus digastricus
This muscle (see ill. 78-80, p. 102) consists of two
muscle bellies that differ completely with regard to
their origin and are usually connected by a cylin-
drical intermediate tendon, although a large num-
ber of anatomical variations exist (comp. Platzer,
Pomeroli). The muscle extends through a fascia
loop at the hyoid and the greater horn of the hyoid.
The anterior belly originates immediately adjacent
to its counterpart in the mandible, in the digastric
fossa, and lies on the middle portion of the oris
diaphragm. Sometimes the anterior belly lies fan-
shaped on the oris diaphragm, the direction of its
fibers following those of the mylohyoid, so that the
floor of the oral cavity appears doubled. This varia-
tion and innervation of the anterior belly by the
mylohyoid nerve indicates that both muscles origi-
nate from a common structure.
The posterior belly of the digastric muscle origi-
nates in the mastoid notch of the temporal bone
and resembles a cone, with its sides pressed toge-
ther. It lies inferior to the origin of the longissimus
and splenius capitis muscles, extends behind the
parotis anteriorly and inferiorly and continues to
the anterior border of the sternocleidomastoid to
the intermediate tendon of the hyoid. It is general-
ly surrounded by the stylohyoid, which forms a
genetic unit along with the posterior belly of the
digastric muscle, as indicated by the mutual inner-
vation via the facial nerve (see ill. 81, right).
Functions of the Musculus digastricus
When the hyoid is fixed, this muscle serves as a
mouth opener. After an initial protraction move-
ment by the inferior head of the Musculus ptery-
goideus lateralis caput inferius, its contraction
rotates the mandible to an extreme mouth open
position. In cases of a loose ligament structure, this
may occasionally result in anterior over-rotation. In
a case of an anatomically shorter articular eminence,
this may lead to an open mouth lock (habitual lux-
ation) (see ill. 82-86, p. 104).
When the dental arches are stabilized in a position
from the occlusion, this muscle is an efficient raiser
of the hyoid, working synergistically with the mylo-
hyoid. If the mandible is in protruding position, the
muscle can carry out a symmetric or asymmetric
recovery movement.
103
Structures - the Neuromuscular System
Platzer, W., Pomaroli, A.: Zur Anatomie der Kiefergelenke.
Fortschr. Kiefer-Gesichtschir. 25: 1–2, 1980
Platzer, W.: personal communication
Ill. 81: The complexity of the suprahyoid muscular connec-
tions can be surmised from this illustration. The stylohyoid
muscle with its functional connection to the digastric muscle
is seen.
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R. Slavicek • The Masticatory Organ
104
Ill. 82: Origin and insertion of the digastric muscle and
its vectors.
Ill. 83: After initial protrusion from the lateral pterygoid
muscle, the digastric muscle may serve as an extreme
opener.
Ill. 84: With cranial support, the digastric muscle acts as
a hyoid lifter.
Ill. 85: From a protrusive position, the digastric muscle is
an efficient retractor during symmetric or asymmetric
movement.
Ill. 86 (right): This sketch shows the exceptionally effi-
cient steering potential of the digastric muscle, via the
hyoid, to the mandible.
Ill. 82 Ill. 83
Ill. 84 Ill. 85
Ill. 86
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Structures - the Neuromuscular System
105
Ill. 87: The total supra- and infrahyoidal complex is illustrated. The central role of the hyoid as the control point and changeover
point becomes evident.
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The digastric muscle is one of the most versatile
muscles of the stomatognathic system. It plays an
important role in most functions of the masticato-
ry organ, but is often neglected in diagnostics (see
ill. 81, p. 103).
Innervation of the Musculus digastricus
The mandibular belly is supplied from the third
branch of the motor portion of the trigeminal
nerve. The mastoid belly is supplied by the facial
nerve.
Musculus stylohyoideus
The stylohyoid (see ill. 88, left) is a rounded mus-
cle originating from and around the styloid
process. Near the hyoid, it mainly surrounds the
tendons of the digastric muscle and inserts in the
loop of its tendon and the body of the hyoid. The
muscle lies posterior to the Musculus styloglossus
and superior to the Musculus stylopharyngicus.
Functions of the Musculus stylohyoideus
The stylohyoid retracts the hyoid to a posterior-
superior position during deglutition. Its insertion
in the loop of the fascia might serve to promote 
a friction-free gliding movement of the digastric
muscle.
Innervation of the Musculus stylohyoideus
The stylohyoid is innervated by the Nervus facialis.
Musculus geniohyoideus
This short, powerful muscle (see ill. 89 and 90, p.
107) lies on the oris diaphragm and supports the
floor of the oral cavity. It originates in the crest of
the geniohyoids and its muscle fibers join those of
the Musculus genioglossus. It inserts in a wide
ridged area on the outer side of the body of the
hyoid.
106
R. Slavicek • The Masticatory Organ
Ill. 88: The steep, superiorly directed vector of the stylohyoid
muscle allows for retraction and lifting of the hyoid, plus the
"tightening of the loop", permitting better gliding of the
connecting tendons of the digastric muscle.
Its insertion in the loop of the fascia might
serve to promote friction-free gliding move-
ment of the digastric muscle.
The stylohyoid is innervated by the Nervus
facialis.
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Structures - the Neuromuscular System
107
Ill. 89: The origin and insertion of the geniohyoid muscle shows that it is an efficient elevator of the hyoid, and
is also a powerful jaw opener when the hyoid is fixed. Along with the mylohyoid muscle, it is substantially
involved in deglutition. 
Ill. 90: The geniohyoid muscle is illustrated from a superior view. This picture shows its position relative to the
mylohyoid muscle.
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Functions of the Musculus geniohyoideus
This muscle pulls the hyoid anteriorly and raises it
superiorly. When the hyoid is fixed, it lowers the
mandible. The geniohyoids, mylohyoids and
digastric muscles raise the tongue during degluti-
tion like a plunger, to a superior-anterior position,
so that the bolus is forced against the isthmus of
fauces when the lips are closed.
Innervation of the Musculus geniohyoideus
The geniohyoid is innervated by the Nervus
hypoglossus.
Musculus genioglossus
This tendinous muscle originates in the double-
cusped spine of the genioglossi (Spina muscularis)
along with its contralateral counterpart, and is the
most powerful of the lingual muscles. The fibers
of both Musculi genioglossi extend radially to the
tip, the back, and into the floor of the tongue.
They form the lingual aponeurosis and simultane-
ously the main body of the vertically ascending
fibers.
Function of the Musculus genioglossus
This muscle lowers the back of the tongue and
effects an outward extension of the tongue. In
cases of unilateral paralysis, the tongue is inclined
to move to the non-affected side, whereas the
opposite may happen in unilateral hyperactivity.
The tendons are liable to initially calcify and after-
wards ossify with advancing age, especially in
edentulous patients with severe atrophy.
Musculus hyoglossus 
This muscle originates in the greater horn of the
hyoid and extends to superior-anterior, where it is
inserted in the outer aspect of the M. genioglossus,
separated by the inferior longitudinal muscle. The
M. genioglossus and M. hyoglossus form a channel,
called the lateral lingual groove, in which the supe-
rior lingual aponeurosis extends to the tongue.
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R. Slavicek• The Masticatory Organ
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Functions of the Musculus hyoglossus
The Musculus hyoglossus also belongs to the ver-
tical-fiber group. It extends to the lingual aponeu-
rosis and acts as a retractor of the tongue. Several
bundles of the Musculus chondroglossus, which
originate in the lesser Corno minus, lie on the
inner side.
Musculus styloglossus
It originates in the Processus styloideus and the
Ligamentum stylomandibulare, passes through
the body of the tongue from behind and joins the
fibers of the superior longitudinal muscle. It
extends to the tip of the tongue and "meets" there
with its counterpart.
Function of the Musculus styloglossus
The function of the Musculus styloglossus is to
change the shape of the tip of the tongue and the
anterior margin.
Musculi linguae (the tongue)
Because of the several finely bundled muscle spin-
dles in the lingual musculature, the tongue is
exceptionally mobile. It is involved in the "milk-
ing action" of infant mammals. This first instinc-
tive behavior pattern is simplified and falsely
described as "suckling". This implies that the
mother's milk is "sucked out" by active sucking
from a vacuum created by the diaphram through
the pulmonary system. This is incorrect. This
mechanism should be termed a milking action,
because the mother's mammary papilla, including
the areola, is grasped by the mandible in a pro-
trusive position and milked out incursively. The
milking action is also supported by a mechanically
developed vacuum, which is caused by a channel-
shaped cavity of the tongue on one hand, and the
incursive movement of Bichat's fat pad on the
other. This negative pressure may amount to 100-
200 mm Hg. The milking action sequence is com-
pleted by completing the incursive movement fol-
lowed by deglutition.
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Structures - the Neuromuscular System
It is involved in the "milking action" of infant
mammals. 
The milking action is also supported by a
mechanically developed vacuum, which is
caused by a channel-shaped cavity of the
tongue on one hand, and the incursive 
movement of Bichat's fat pad on the other.
This negative pressure may amount to 100-
200 mm Hg.
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After infancy, the tongue is substantially involved
in mastication. It forms and then transports the
bolus by transfering it during swallowing to the
isthmus musculature. The tongue is also a main
prerequisite for speech, as it is necessary for the
formation of lingual, dental and palatal sounds.
The abundantly available muscle spindles allow for
the tongue's excellent proprioceptivity, making it an
excellent sensory organ. The tongue is a focal point
in the masticatory organ due to it giving rise to the
sense of taste, along with related psychological ram-
ifications. The internal muscles of the tongue origi-
nate and insert in the aponeurosis and the lingual
septum. The direction of the muscle fibers gives rise
to their respective names, as follows: 
• Musculus verticalis linguae
• Musculus transversus linguae
• Musculus longitudinalis linguae superius
• Musculus longitudinalis linguae inferius
Functions of the tongue
The tongue is involved in all important functions of
the masticatory organ. This also applies to para-
functions and hyperactivities. In diagnostics, special
attention must be given to the lingual surface, the
lingual borders, and the tongue's behavior in
regards to mobility and motility. The internal mus-
cles serve the high precission-motor action of form-
ing the tongue during this function.
Innervation of the lingual musculature
Innervation of the lingual musculature is supplied
from the Nervus hypoglossus.
The musculature of the soft palate,
the pharyngeal vestibule and the
pharynx
The muscles of this region are involved in all func-
tions of the masticatory organ. The functional areas
formed by these muscles are involved in respiration
and speech. These areas must be given important
consideration in diagnostics, with regard to both
function and dysfunction. Their association with
the pathology of the superior respiratory passages
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R. Slavicek • The Masticatory Organ
Parafunctions and hyperactivities. 
Innervation of the lingual musculature is sup-
plied from the Nervus hypoglossus.
The abundantly available muscle spindles
allow for the tongue's excellent proprioceptiv-
ity, making it an excellent sensory organ. 
After infancy, the tongue is substantially
involved in mastication. 
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requires a good understanding of this portion of the
muscular apparatus on the part of the dentist. For
this reason, we need to have complete knowledge
of the morphology of this region.
Musculus levator veli palatini
Its thick, parallel-fibered muscle belly originates
in a narrow, rounded form, from the basal surface
of the temporal bone pyramid. It lies medial to
the thin plate of the tensor of the palatine velum
on the lateral wall of the pharynx and forms the
main mass of the soft palate. The levator muscle
of the palatine velum lies on the tube, medial
from the tube's canal, anterior to the entrance of
the carotid canal, forming a duct in the lower cir-
cumference of the tube. Its fibers interweave with
those of its contra-lateral partner and with those
of the Musculus palato-pharyngicus.
Function of the Musculus levator 
veli palatini
The two levators allow the soft palate to contract
and, as parallel-fibered muscles, to raise the poste-
rior pharyngeal wall extensively, so that the pha-
ryngeal nasal cavity is closed against the intrusion
of food. The levator of palatine velum causes a dis-
tinct bulge in the mucous membrane in the lower
circumference of the tube aperture and forms a so-
called levator bulge, which narrows the entrance to
the canal. 
Regarding the tube itself, the levator muscle of
palatine velum acts synergistically with the tensor
muscle of the palatine velum to dilate, as it forces
the auditory cartilage posteriorly and superiorly.
After the synergetic action of the two muscles, the
elastic cartilage returns to its neutral position, the
tube narrows and Ostmann's fat pad pushes later-
ally against the cartilaginous medial wall.
In further consideration of phonation, the network
of muscles in the soft palate makes for a finely
adjustable accommodation apparatus, which is
involved in the phonation of vowels and the tone of
the voice. This region is therefore of great interest
in phonology.
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Structures - the Neuromuscular System
Myon
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Innervation of the Musculus levator veli
palatini
is supplied from the facial nerve.
Musculus levator uvulae
This rounded pair of muscles originates in the pos-
terior nasal spine and extends between the various
mucous glands of the uvula as a united body of
muscle.
Function of the Musculus levator uvulae
Bilaterally innervated, this muscle raises the
uvula. Unilaterally innervated, it pulls the uvula
laterally. Interestingly, in cases of strong unilate-
ral contraction of the retro-maxillary muscles and
through the involvement of soft palatal muscles
during phonetic activity, the uvula is diverted to
the side under tension (see ill. 91, p. 115).
Innervation of the Musculus levator uvulae
Innervation of the levator muscle of the uvula is
supplied from the facial nerve.
Musculus glossopalatinus
In conjunction with the transverse lingual muscle,
this muscle can narrow the pharyngeal opening.
Innervation of the transverse lingual is supplied
from the glossopharyngeal nerve.
Musculus palatopharyngicus
This muscle can raise the larynx and also shorten
the pharyngeal head. It is actually a palatal pha-
ryngeal larynx. Innervation is supplied from the
glossopharyngeal nerve and the vagus nerve.
Musculus tensor veli palatini
This muscle is a powerful contractor of the soft
palate and, together with the levator of the pala-
tine velum, a dilator of the tube (Musculus dilata-
tor tubae), whereby ventilation of the middle ear
takes place. The result can sometimes be heard as
112
R. Slavicek • The Masticatory Organ
Innervation of the Musculuslevator veli pala-
tini is supplied from the facial nerve.
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a (clacking) sound during "empty" deglutition. In
cases of dysfunction in the stomatognathic sys-
tem, these topographic and functional areas
should not be underestimated. The symptomato-
logy regarding the relationship with the auditory
region has not yet been amply researched, but
should nevertheless be considered carefully from
the viewpoint of functions of muscles related to
the tube. Worthy of special note is the close prox-
imity to the medial pterygoid, the main muscle
involved in parafunction.
Somatomotoric innervation of the tensor of the
palatine velum is supplied from the glossopharyn-
geal nerve from the otic ganglion via Jacobson's
anastomosis.
The pharynx - throat
The respiratory passages and alimentary canals
share a large vestibule posterior to the oral and
nasal cavities, namely the pharynx (throat). It
extends from the roof of the pharynx, the pharyn-
geal fornix, to the entrance of the esophagus. The
pharyngeal head is a flatly pressed choana
attached on its wider side to the skull and open-
ing into the esophagus.
The pharyngeal cavity consists of three levels:
• The upper: epipharynx (Pars nasalis pharyn-
gis, nasopharynx)
• The middle: mesopharynx (Pars oralis pharyn-
gis)
• The lower: hypopharynx (Pars laryngica)
Epipharynx
In the lateral region of the epipharynx behind the
choanae, there is an elongated opening in the
extension of the inferior nasal cavity - the pharyn-
geal opening of the auditory tube, measuring
approximately 6 mm in length. It leads into the
tube and further into the spaces of the middle ear,
which can thus be ventilated by the pharynx. In
children, the pharyngeal opening to the tube is
surrounded by lymphatic tissue (tonsilla tubalis).
The epipharynx extends superiorly to the cranial
base where its roof, the pharyngeal fornix, is firm-
ly united with the body of the sphenoid bone, the
pyramids of the temporal bone and the basal por-
tion of the occipital bone.
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Mesopharynx
The respiratory and alimentary passages intersect
in the oral part of the pharynx. During degluti-
tion, the soft palate and posterior pharyngeal
wall- Passavant's ridge - close the access from the
mesopharynx into the epipharynx. The mesopha-
rynx is visible in the region of the faucal isthmus,
where the floor of the tongue lies with the lingual
tonsils on the posterior pharyngeal wall. The lym-
phatic tissue of the lingual floor overhangs the
right and left palatal and tubular tonsils, together
with tonsillar tissue from the epipharynx, and
forms the lympho-reticular pharyngeal ring. In
cases of strong hypertrophy of lymphatic tissue in
growing children, the respiratory passages may be
constricted. This is compensated for by a postural
change, i.e. by moving the head to the front.
According to several authors, this postural modi-
fication and the tendency towards oral respiration,
commonly associated with it, influence the
growth of the viscerocranium (comp. Linder-
Aronson, Fränkel, Björk).
Hypopharynx
In the laryngeal portion, the pharynx is even more
constricted. On its anterior wall the larynx bulges
with annular and arytenoid cartilage and their
musculature. By pressing the raised larynx against
the base of the tongue, the respiratory passage is
closed against the hypopharynx (see ill. 92, p. 115).
The entire pharyngeal posterior wall lies on the
spinal column. The elongated furrows of the
esophageal mucous membrane start at the level of
the lower third of the annular cartilage plate. The
passage of the pharynx into the alimentary canal
is known as the mouth of the esophagus. It lies at
the level of the 6th cervical vertebra. The right
and left muscle appendages of the longus muscle
and cervical rectus push the posterior pharyngeal
wall and its line of origin to the spheno-occipital
syndesmosis convexly forward, so that a recess is
formed between the two insertion arches, filled
with lymphatic tissue from the pharyngeal tonsil.
The musculature of the most cranial portion of
the pharyngeal opening is of significance to the
dentist because the anterior regions are connected
with the mandible.
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R. Slavicek • The Masticatory Organ
Linder-Aronson, S., Behfelt, K., Neander, P.: Posture of the
Head, the Hyoid Bone and the Tongue in Children with and 
without Enlarged Tonsils. Eur. J. Orthod. Mov. 12 (4):
458–67, 1990
Hellsing, E., Forsberg, C. M., Linder-Aronson, S.,
Sheikholeslam, A.: Changes in Postural EMG Activity in the
Neck and Masticatory Muscles Following Obstruction of the
Nasal Airways. Eur. J. Orthod. Mov. 8 (4): 247–53, 1986
Fränkel, Ch., Fränkel, R.: Der Funktionsregler in der 
orofazialen Orthopädie. Verlag Hüthig, Heidelberg 1992
Björk, A.: The Face in Profile. Svensk Tidskr. 40 
(Suppl 5 B), 1947
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Structures - the Neuromuscular System
115
Ill. 91: Clinical picture of a unilaterally "tensed" patient showing the distinct asymmetric entrance to the phar-
ynx during tension.
Ill. 92: The laryngeal portion of the hypopharynx with the epiglot-
tis, which is raised muscularly to cover the laryngeal entrance during
deglutition. Thus, a complex switchblade between the respiratory
and the digestive canal was achieved - an equally necessary new
function from an evolutionary point of view.
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Musculus constrictor pharyngis superius 
It originates in a long line from the angle of
mandible, upwards up to the pterygoid process of
the sphenoid. Four areas can be distinguished in
the muscle:
• The Pars mylopharyngica, whose fibers origi-
nate from the angle of mandible behind the 
last molar posterior to the mylohyoid line.
• The Pars glossopharyngica, as a direct exten-
sion of the transverse lingual muscle in the 
pharyngeal wall.
• The Pars buccopharyngica, whose Raphe
pterygomandibulare forms a tendinous con-
nection to the Musculus buccinator in the pha-
ryngeal wall.
• The Pars pterygopharyngica are the most 
superior, its fibers leading from the hamulus 
and from the medial lamella of the pterygoid 
process, and passing between the levator and 
tensor of the palatine velum.
Innervation of the pharynx
The motor nerves originate in the pharyngeal
plexus formed by the 9th and 10th cranial nerves
and the sympathicus, and extend onto the poste-
rior pharyngeal wall. The 9th and 10th cranial
nerves supply the mucous membrane with senso-
ry and parasympathetic nerves. The mucous
membrane nerve of the piriform recess is the
internal recess of the superior laryngeal nerve.
Muscles of the larynx
The dentist concerned with functional diagnostics
must have a basic knowledge of the laryngeal
musculature in order to determine the differential
diagnosis of the rather frequently occurring ail-
ments in this region. Patients may develop cramps
in the cervical region, a choking feeling, and occa-
sionally spontaneous hoarseness. It is necessary for
the dentist to work in cooperation with otolaryn-
gologists and logopedists.
The larynx hanging on the hyoid, the trachea, and
the thyroid gland connected with it, are all
involved in movements of the hyoid, which in turn
depend on the antagonism of the superior and
inferior hyoid musculature. Pharyngeal muscles
attached to the larynx and the palatopharyngeal
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R. Slavicek • The Masticatory Organ
The dentist concerned with functional diag-
nostics must have a basic knowledge of the
laryngeal musculature in order to determine
the differential diagnosis of the rather fre-
quently occurring ailments in this region. 
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larynx, leading from the soft palate, not only
move the larynx but can also fix it at various
heights, so that the vocal cords supported by the
laryngeal cartilage are able to make sounds
according to the position of the attachment tube.
Because the pharyngeal opening and its muscula-
ture work in conjunction with lingual muscles and
those of the floor of the mouth, function-based
tension understandably influencesthe functioning
of the larynx. Evolution in humans brought about
entirely new high-precision tasks for the NMS.
For many humans in current times, the most
important function is that of "speech". It is there-
fore illogical that so little attention is given to the
stomatognathic aspect when studying the causes
of dysfunction in the larynx.
In addition to muscles that raise and lower the
entire respiratory tract, the larynx has its own
muscles with which it dynamically controls the
(true) glottis. The movement of laryngeal carti-
lages against each other (in respiration and phona-
tion) is rendered possible by specific obliquely stri-
ated muscles. The laryngeal muscles consist of five
paired muscles and one unpaired muscle.
The paired muscles are as follows: 
• Musculus cricothyreoideus (innervation:
Recessus externus of the Nervus laryngicus
superius)
• Musculus cricoarytaenoideus posterius
• Musculus cricoarytaenoideus lateralis
• Musculus thyreoarytaenoideus (innervation:
Nervus recurrens)
• Musculus vocalis (innervation: Nervus laryn-
gicus inferius)
The unpaired muscle is:
• Musculus arytaenoideus
Innervation
Laryngeal muscles are innervated from the right
and left vagus nerves. The nerve fibers originate in
the ganglion cells of the laryngeal core in the
medulla oblongata, the nucleus ambigus and
reach the larynx through the superior and inferior
laryngeal nerves.
In the formation of sound, three mechanisms are
at work: the respiratory apparatus, the phonation
apparatus and the articulation apparatus in the
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Structures - the Neuromuscular System
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pharynx. Of course, not only the formation of
sound, but also its translation into "speech" are of
interest. This complex concept of speech involves
all structures of the masticatory organ under the
supervision of specific brain centers.
Muscles related to the posture of the
head, the throat, neck and scapular
girdle
As discussed in the chapter dealing with evolu-
tion, evolutionary phylogenetic modifications in
posture led to an upright and walking being, and
to subsequent phylogenic developments. This
region has become important for the diagnosis of
functional disorders of the masticatory organ, as
the prevalence of postural problems in humans is
increasing. Studies performed on schoolchildren
indicated dysfunctional body posture in nearly
100% of the cases (comp. Tilscher). From running
to walking to squatting, human beings have
become static sedentary individuals, whose
dynamics primarily take place in the brain i.e., in
the intellect. Because of the integration of essen-
tial portions of the cervical musculature
(neck/throat) in the stomatognathic system, prob-
lems frequently arise in this area. A causal classifi-
cation of these problems is, however, most difficult
to make.
For exactly this reason, diagnostic and therapeutic
interdisciplinary cooperation is essential.
The head and trunk are connected to each other
posteriorly by the neck and anteriorly by the
throat. Posteriorly the cervical spine is supported
and protected on both sides by the covering pro-
jections of neck muscles. In the caudal region, the
cervical spine is overlaid by the function-based,
migrated scapular girdle (Levator scapulae, 
rhomboideus, trapezius) (see ill. 93, p.119). The
anterior lateral trunk muscles insert directly in the
skeleton of the visceral tract, the sternum, the
clavicle and the first rib (see ill. 94-95, p. 120-
121). The supra- and infrahyoid muscles join on
the moveable hyoid, which assumes a significant
role here as the center of the entire vector system
of this complex muscle apparatus. The muscles
also simultaneously cover and support the thyroid
gland and the larynx. The pre-vertebral group
forms a soft pad for the visceral tract in front of
and lying on the cervical spine. The scalenus group
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R. Slavicek • The Masticatory Organ
Tilscher, H.: Das Bewegungssegment der Wirbelsäule im
Blickpunkt der orthopädischen Rückenschule. Medizinisch-
literarische Verlagsgesellschaft, Uelzen 1993
... has become important for the diagnosis of
functional disorders of the masticatory organ,
as the prevalence of postural problems in
humans is increasing. 
The head and trunk are connected to each
other posteriorly by the neck and anteriorly
by the throat. 
The supra- and infrahyoid muscles join on
the moveable hyoid.
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Structures - the Neuromuscular System
119
Ill. 93: The complexity of the trunk-neck-head connection is clearly seen in this illustration. The muscles have to ensure perfect pos-
ture, balance, and especially mobility. Several cumulative problems emerge in this region because of man's evolutionary "regression"
to a predominantly static, sedentary being.
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R. Slavicek • The Masticatory Organ
120
Ill. 94: The problems of posture and mobility are more complex and more susceptible to dysfunction, because of the intermediate
location of the hyoid and its expanded area of responsibility, especially the "positioning function" in speech.
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Structures - the Neuromuscular System
121
Ill. 95: This illustration shows that ventral and dorsal functions are extended by the task of having to provide muscular connec-
tions.
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covers the upper thoracic aperture and also the tips
of the lungs from the side.
Above the previously mentioned muscle groups
lies the incomplete muscular layer of the trapezius
and sternocleidomastoid muscles, extending from
the sternum and clavicle to the cranium. The
muscles are innervated by the accessory nerve and
both originate at the skull. The trapezius pushes
against the thoracic girdle and extends down the
spinal vertebrae to the 12th thoracic vertebra (see
ill. 96, p. 123). M. sternocleidomastoideus inserts at
the sternum and the clavicle (see ill. 97, p. 124).
The entire muscle layer has three large windows.
Two triangular windows (one right, one left), are
demarcated by the trapezius and sternocleidomas-
toid, which is also designated the Trigonum colli
laterale (dexter et sinister). A third medial window
formed by the two sternocleidomastoid muscles is
the ventral cervix of the trigonum.
The lateral cervical triangles are formed at their
base by the clavicle, their apexes extend posterior-
ly to the angle of the mandible. The floors of the
cavities are formed by the splenius muscle, the
levator of the scapula and the scalenus muscle.
The most inferior portion forms the greater supra-
clavicular fossa. The inferior belly of the omohy-
oid crosses here; vessels and nerves to the upper
extremities also extend through this point.
The middle triangle of the neck contains muscles
innervated from the vagus nerve, as well as the
overlying musculature innervated from the
hypoglossus nerve. The base of the triangle is
formed by the hyoid bone. The skin of the throat
shows a retraction here, the "hyoid groove". The
apex of the anterior triangle forms the "jugular
fossa" (Fossa jugularis) above the episternum.
Superiorly, the retromandibular fossa is formed
between the angle of the mandible and the ante-
rior margin of the sternocleidomastoid, extending
to the lateral wall of the pharynx. In the retro-
mandibular fossa, three thin muscles originate on
the styloid process: the M. styloglossus, the M.
stylohyoideus and the M. stylopharyngicus.
Innervation
The muscles receive their neural supply from va-
rious sources. A considerable portion of the liga-
mentary attachment apparatus of the hyoid also
originates in the styloid, namely the stylohyoid
ligament. This phylogenetically modified, concep-
tually new self-centering ligamentary attachment
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R. Slavicek • The Masticatory Organ
The inferior belly of the omohyoid crosses
here; vessels and nerves to the upper extremi-
ties also extend through this point.
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Structures - the Neuromuscular System
123
Ill. 96: The covering in the posterior and anterior areas is incomplete.
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R. Slavicek • The Masticatory Organ
124
Ill. 97: The anteriorcovering is also incomplete.
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is of systemic-diagnostic significance and should
not be neglected in cases of dysfunction. In the
anterior regions, the throat is overlaid by the
platysma (see ill. 98-99, right).
The neural supply to the various layers is an out-
come of the complicated phylogenic development
of this region extending from the pharyngeal arch
and primitive vertebrae surrounding the cervical
spine and cervical viscera.
The pre-vertebral muscles
Musculus rectus capitis ventralis
The short ventral rectus capiti extends obliquely
from the lateral massa of the atlas towards the
basal portion of the occipital bone, to immediate-
ly before the foramen magnum. It forms a tena-
cious connection between the atlas and the skull
and is, as a rule, involved in posture-related ten-
sion.
Musculus longus capitis
This powerful, elongated muscle plate originates
from the carotic tubercle (CV 6) and the three to
four superiorly and anteriorly positioned oblique
cusp processes, and extends to the basal portion of
the occipital bone. It causes a bulge in the poste-
rior pharyngeal wall and inserts in a flat pit on the
occipital bone.
The longus capitis muscle causes a forward tilting
of the head and simultaneously forms a soft cush-
ion, where the loose gliding tissue in the
retropharynx is located, whereby the visceral tract
remains mobile in front of the spine during speech
and deglutition. It can compensate for strong ver-
tical loss by inversely bending the cervical spine,
thus reducing tension in the anterior cervical
region (see ill. 100-101, p. 126).
Musculus longus colli
This long neck muscle is also an elongated three-
sided muscle plate. The function of this muscle is
to serve as a lateral benderof the body. When
bilaterally innervated, it stretches the lordosis of
the cervical spine.
At this point it would be appropriate to mention
the Musculus rectus capitis lateralis, belonging to
the intercostal muscles. It is an efficient lateral body
bender and connects the lateral portions of the atlas
to the cranial base. It is frequently involved in
problems of the atlanto-occipital region.
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Structures - the Neuromuscular System
Ill. 98: The platysma covers the anterior neck-visceral tract
to a varying extent.
Ill. 99: Because of its width in the mandibular insertion, the
platysma is involved in the functional placement mechanism.
In cases of respiratory distress, expansion of the respiratory
passages and dilation of the efferent vessels are effected by
means of external contraction.
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R. Slavicek • The Masticatory Organ
126
Ill. 100: Computerized tomogram of a patient with a severe dysfunction and a greatly reduced distance
between the maxilla and the mandible. Note the inverse flexion of the cervical spine and the strong retraction
of the hyoid.
Ill. 101: The patient's X-ray shows the extreme skeletal relationship and dental deep bite.
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Musculi scaleni 
The scalenus muscles are relics of intermediate rib
muscles, rising to cranial from the superior tho-
racic ribs to the costal elements of the cervical
spine. Together they form a deep muscular cone,
attached on the wide 1st rib, which protects the
cervical pleura and helps to keep the lungs warm.
The tips of these muscles extend to the oblique
processes of the superior cervical vertebra and
their base extends, with two peaks, onto the 1st
rib and the third peak on the 2nd rib. The mus-
cles are known as step muscles (scala=step).
Function and innervation
Unilaterally innervated, the scalenus muscles are
responsible for lateral bending of the cervical spine.
Bilaterally innervated, they raise the 1st rib and
thereby also the superior portion of the thorax.
They are very powerful inhalation muscles during
thoracic respiration, especially when the neck and
head are tilted back. In tense or anxious individu-
als, they contribute to inefficient and shallow tho-
racic respiration. At the same time, in cases of
improper and tense sitting posture, they are involved
in functional shortening of the cervical spine. They
may also be involved in phonetic problems. 
The infrahyoid muscles
In the angle between the inferior facial area and
the anterior cervical area, one can clinically pal-
pate the body of the hyoid. Three band-shaped
muscles descend from it and cover the ligaments
protecting the visceral tract. One of these muscles
is divided obliquely into two parts by a narrow,
tendinous attachment (Inscriptio tendinea) on the
thyroid cartilage. Above it lie the sternohyoid and
omohyoid muscles; below these two lies the ster-
nothyroid muscle with its extension to the hyoid,
and the thyrohyoid muscle (see ill. 102 and 103,
right).
Musculus sternohyoideus
This thin, long band of muscle originates from the
posterior side of the sternoclavicular joint and
extends upwards from the superior thoracic aper-
ture, covering the thyroid, to the superior border
of the body of the hyoid. This muscle stabilizes
the hyoid.
127
Structures - the Neuromuscular System
Ill. 102: The vector illustrations above and below demon-
strate the significance of the interplay between supra- and
infrahyoid muscles.
Ill. 103: The force of combined functions also shows the
direct connection with the sternoclavicular joint and the two
temporo-mandibular joints. The function of the anterior
mimic muscles, as powerful occluders, demonstrates the
complex interplay of several muscle components.
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R. Slavicek • The Masticatory Organ
128
Ill. 104: First of all, the infrahyoid group connects the hyoid directly or indirectly in a relatively straight line with the sternum and
the clavicle. More complex is the omohyoid muscle, extending from the scapula and inserting in the hyoid. This attempt to illus-
trate its vector shows an "intermediate insertion" in the cervical fascia.
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Musculus omohyoideus
This muscle (see ill. 104, p. 128 and ill. 105, right)
lies lateral to the sternohyoid and is frequently sep-
arated into two band-shaped muscle bellies by a
ligament-like, intermediate tendon, joining again
at a nearly perpendicular angle. The inferior belly
leads from the scapula. It originates medially from
the superior notch of the scapula on its upper mar-
gin, is of variable width, fixed to the clavicle with
the sturdy cervical aponeurosis (Fascia omoclavicu-
laris), and extends over the scalenus gap. The liga-
ment-like intermediate tendon lies on the internal
jugular vein and is attached to its adventitia so that
the muscle can dilate the vein by contraction. The
superior belly runs parallel to the sternohyoid and
inserts lateral to it in the body of the hyoid.
Because of its functional topography - it originates
in the dorsal functional region of the scapula and
switches to the ventral functional region of the
hyoid muscles - the omohyoid is a significant "con-
veyer" of frequently improper scapular posture to
the hyoid, and thereby to the mandible (see ill. 106,
right and ill. 107, p. 130).
Musculus sternothyreoideus
Below the previously described muscles lies the
wide, thin band of the sternothyreoid muscle, which
originates from the middle of the inner side of the
episternum, somewhat more superior than the ster-
nohyoid, and from the cartilage of the 1st rib. The
right and left muscles first meet in the middle, then
extend superiorly to the oblique line of the thyreoid
cartilage, diverging and covering the thyreoid gland.
Innervation of the inferior hyoid muscles is pro-
vided by the 2nd -3rd cervical nerve, through
hypoglossal branches, formed by the descending
hypoglossal recess and the descending cervical
recess. Each of the two parts of the muscle has its
own neural branch.
Musculus thyreohyoideus
From the oblique line of the thyreoid cartilage and
separated from the sternothyreoid, as if by a tendi-
nous attachment, the thyrohyeoid extends superior-
ly to the dorsal area of the lateral third of the body
of the hyoid, and to the greater horn of the hyoid.
Innervation is providedfrom the 1st and 2nd cer-
vical nerves through a direct branch of the
hypoglossus nerve.
129
Structures - the Neuromuscular System
Ill. 105: This simplified lateral view demonstrates the con-
nections between the posterior and anterior areas, and has
the possibility of influencing the position of the hyoid. The
position of the mandible is indirectly co-determined by the
functions of the posterior group.
Ill. 106: In this isolated view, the rather lateral origin on the
scapula is shown.
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R. Slavicek • The Masticatory Organ
130
Ill. 107: The medial insertion of the omohyoid muscle on the hyoid demonstrates the fact that problems in the scapular region may
be transferred to the hyoid.
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Functions of the infrahyoid muscles
The combined effect of infrahyoid muscles is to fix
the hyoid so that it can function as a stabilizer for
the action of the superior hyoid muscles on the
mandible and the tongue. They can lower the
hyoid with the larynx so that the attachment tube
of the glottis becomes extended. As they insert in
the same skeletal region as the hyopharynx and
laryngopharynx, they also serve to initiate deglu-
tition.
The thyreohyoid raises the thyreoid cartilage and,
thereby, the entire larynx against the hyoid during
deglutition, so that the opening to the larynx can
be sealed by the epiglottis. The omohyoid is a fas-
cia tensor and can therefore dilate the deep cervi-
cal veins. It is involved in unilateral and bilateral
tension in the scapula region (Musculus levator
scapulae) and also influences the position of the
mandible through its insertion in the hyoid bone.
Tension leads to a compensating increase in activ-
ity in the adductor region of the mandible. The
influence of this muscle in cases of stress on the
venous outflow of the greater cranio-cervical ves-
sels in vascular headaches has not yet been fully
researched.
Musculus sternocleidomastoideus
This muscle originates with two heads from the
sternum and the clavicle (see ill. 108, right). The
head originating from the episternum (sternoclei-
domastoid muscle) inserts on the mastoid process.
The second head originates in the medial third of
the clavicle and extends to the mastoid process
and the occipital bone of the superior line of nucha
(cleidomastoid muscle and cleido-occipital mus-
cle). Its superior half covers splenius, the levator of
the scapula and the posterior belly of the digastric
muscle; its inferior half covers the greater cervical
vessels.
Function of the Musculus 
sternocleidomastoideus
From its position in the cervix of the fascia, this
muscle has considerable influence on the position
of the mandible; it turns the head and tilts it to
the side (see ill. 109, right). Its contraction affects
the atlanto-occipital joint, as well as, all joints of
the cervical spine. This muscle holds the head
131
Structures - the Neuromuscular System
Ill. 108: The origin of the powerful, two-headed sternocleido-
mastoid muscle, with is origins on the sternum and clavicle,
and its insertion on the mastoid process and superior nuchal
line of the occipital bone, establishes it as an exceptionally
important muscle for the mobility of the head.
Ill. 109: This vector illustration shows the diversity of its
functions as a rotator and incliner of the head.
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upright, but can also tilt it posteriorly. In its posi-
tion lying across the cervical spine, it can throw
the head posteriorly and increase cervical lordosis.
It raises the sternum when the head is fixed, and
is therefore, a supplementary muscle for deep
inhalation. It is significantly involved in forced
thoracic breathing in anxious patients. This mus-
cle serves as a turner of the head, especially when
the individual expresses intense interest. It enables
the eyes and ears to "turn towards" the dominant
sensory side for better perception. This is worthy
of note when evaluating improper posture.
Innervation is provided by the accessory nerve C.
2-4. The nerve bores through the muscle to
extend to the trapezius muscle.
Musculus trapezius
The trapezius muscle (see ill. 110, p. 133) is one of
the several wide back muscles. Its elongated base
lies on the spine and extends inferiorly from the
external occipital protuberance to the 12th tho-
racic vertebral spina. This muscle originates in the
throat, from the septum of nucha in the thoracic
region of the spinae, as a thin, tendinous plate that
extends onto three places on the aponeurosis. One
of the aponeuroses is located near the external
occipital protuberance. When this muscle is high-
ly developed it travels along the superior line of
nucha and joins the insertion of the tendon of the
sternocleidomastoid muscle. The insertion on the
occipital bone is perforated by the greater occipital
nerve and from the A. occipitalis.
Function of the musculus trapezius
Because of the convergent and partially antago-
nistic paths of muscle fibers, the effect of the indi-
vidual parts of the trapezius on the thoracic girdle
is variable. The superior regions of both muscles,
the ascending parts, raise the shoulders. They are
supported synergistically by the levator of scapula
and the rhomboid muscle. The shoulder is able to
bear a load, using these muscles. This should be
especially pointed out to patients who, in spite of
muscular tension and the problems resulting from
it, carry a bag on one side with a shoulder strap,
thereby raising the "load-carrying" shoulder.
Antagonistic muscles from the point of view of
their vectors (superior upwards, inferior down-
132
R. Slavicek • The Masticatory Organ
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Structures - the Neuromuscular System
133
Ill. 110: This image elucidates the fusion of the aponeurotic insertions of the head rotator with the trapezius.
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wards), frequently involve these two areas in
chronic postural problems. In contraction, as well
as in cases of chronic tension, the scapula can turn
on an axis, passing sagittally and horizontally
through the middle of the spine. Observing the
condition of the scapulae in an upright relaxed
posture, is therefore of great diagnostic interest.
Innervation of the trapezius muscle is provided by
the accessory nerve and by ventral branches of the
cervical nerves 1-4.
Musculus levator scapulae
This muscle originates on the oblique processes of
the first four cervical vertebrae and inserts on the
dorsal side of the margin of the scapula vertebra. It
is therefore in direct connection with the oblique
process of the atlas and, because of its especially
effective lever arm, is mainly involved in tension in
the atlanto-occipital region. In one variation, its
origin may extend onto the mastoid process.
Function and innervation of the Musculus
levator scapulae
This muscle raises the scapula and simultaneously
rotates it to the inside. Through tension in the
thoracic girdle, it pulls the cervical spine to the
same side. Innervation is provided by the dorsal
scapular nerve and branches of the cervical plexus.
Summary
The NMS of the human masticatory organ must
be viewed from the standpoint of its extended
functions, especially as its functions may overlap
into other areas. While studying the actual func-
tions of the muscular apparatus of the cranio-cer-
vical region, it is found that there are hardly any
isolated individually classifiable areas, but rather
muscle groups assuming a variety of responsibilities.
Mastication
The NMS functions on the basis of individual pat-
terns, which are carried out under proprioceptive
control and adapted to nutrition. The true mastica-
tory muscles involved are the tongue and the
mimic muscles, the floor of the mouth and the
supra- and infrahyoid musculature.
134
R. Slavicek • The Masticatory Organ
Observing the condition of the scapulae in an
upright relaxed posture, is therefore of great
diagnostic interest.
While studying the actual functions of the
muscular apparatus of the cranio-cervical
region, it is found that there are hardly any
isolated individually classifiableareas, but
rather muscle groups assuming a variety of
responsibilities.
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Deglutition
Deglutition is executed by the adductors, muscles
of the CMS, the soft palate, the pharynx, the
tongue, the floor of the mouth and the supra- and
infrahyoid musculature. Deglutition is one of the
primary functions of the masticatory organ with
its extremely unique morphology, which takes
place frequently, perpetually and generally with-
out a conscious effort.
Speech
Speech is actually the primary function of the
human "masticatory" organ, as it gives rise to the
quality of being human. It involves the true mas-
ticatory muscles, mimic muscles, tongue, floor of
the mouth, supra- and infrahyoid musculature,
larynx, muscles of the superior pharyngeal region
and respiratory muscles including the diaphragm.
Posture of the head
Becoming a true biped created considerably
extended areas of responsibility for the NMS.
Here, it is above all the muscles of the CMS that
assumed entirely new and significant functions.
The true masticatory muscles, such as the supra-
infrahyoid musculature, autochtonal muscles of
the cervical spine, muscles of the atlantocranial
region, the thoracic girdle, and all deep regions of
muscles related to posture, play a major role in the
maneuverability of the human head. The posture
of the head and body are an inseparable entity and
must be regarded as such, both functionally and
diagnostically.
Clenching and Bruxism
As clenching and bruxism are expressions of psy-
chic stress management, we are mainly concerned
with the adductors of the mandible. Muscles of
the CMS are directly involved in these move-
ments. Depending on the individual, the true
masticatory muscles, digastric muscle, floor of the
mouth, tongue, and the mimic muscles are poten-
tially involved.
135
Structures - the Neuromuscular System
As clenching and bruxism are expressions of
psychic stress management, we are mainly
concerned with the adductors of the
mandible. Muscles of the CMS are directly
involved in these movements.
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The determinants of all function of the masticatory
organ are the teeth, for they act as functional inter-
ference to free movement of the mandible. Today,
the dentition is not subjected to high rates of abra-
sion, due to the changes in human nutritional diets.
Therefore, from a diagnostic viewpoint, abrasion
and facets in atypical locations are predominantly
caused by parafunction, which is manifested in spe-
cific teeth, or regions of teeth. The dynamic rela-
tionship of dental arches to each other is of 
utmost importance for the diagnosis of the masti-
catory organ. The structures of the organ are func-
tionally intertwined. The teeth, because of their
rigid structure and their proprioceptive expression
of positional signals, are system-dominant in the
design of functional patterns, which are produced
by the slow, ontogenetic maturation of the masti-
catory organ in functional periods during growth.
The coronal portion of a tooth is the only structure
in the human organism that is structurally mature
before it starts to function. After the tooth erupts,
the coronal portion can only be altered through
irreversible damage to the structure itself. Because
of the invasive nature and capabilities of dental
medicine in all dental disciplines, the stomatog-
nathic system is often forced to adapt rapidly. The
system's adaptive capability is therefore at first
challenged and then strongly required. This adap-
tive process can, but need not necessarily, lead to
new eu- or orthofunction.
These introductory remarks are fundamentally
important in order to discuss the morphology of
the dentition and view the subsequent diagnostic
sequences with an open mind. It should be empha-
136
R. Slavicek • The Masticatory Organ
Occlusion - Articulation
The determinants of all function of the masti-
catory organ are the teeth, for they act as
functional interference to free movement of
the mandible.
Therefore, from a diagnostic viewpoint, abra-
sion and facets in atypical locations are pre-
dominantly caused by parafunction, which is
manifested in specific teeth, or regions of
teeth.
The coronal portion of a tooth is the only
structure in the human organism that is
structurally mature before it starts to func-
tion. After the tooth erupts, the coronal por-
tion can only be altered through irreversible
damage to the structure itself.
Occlusion
Articulation
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sized here that minimizing the significance of
occlusion in current scientific discussions is to be
condemned, and that current worldwide theories
concerning occlusion and articulation should be
justifiably criticized. The responsibility lies above
all with those who would like to minimize the
importance of occlusion for the masticatory organ
and its functions for didactic reasons, in favor of
other "more medical, i.e. less dental" fields. A solu-
tion to this current dental dilemma can only be
found in a more fundamental basic medical educa-
tion and, simultaneously, by communicating
through the teaching process, an optimal know-
ledge of occlusion. Let us not forget that dentists
are specialists in medicine and are responsible for
one of the most important organ systems of the
human organism.
Ontogenesis of the
masticatory organ
The concept of nature in the 
development of dentition; the 
development of the masticatory
organ from the viewpoint of 
functional demands
I intentionally begin this section on occlusion with
a paragraph on the development of dentition, as
this is the best starting point for introducing the
reader to the overall unity of occlusal relationships,
and their resultant functional interdependence.
Diverging from the usual methods of observation
regarding the development of the masticatory
organ, for the purpose of distinguishing between
"normal" and "deviant", it would be meaningful to
regard the growth of the skull and the masticatory
organ from the viewpoint of so-called functional
periods. In other words, the organ should be evalu-
ated according to the functions required to be per-
formed at a particular point in time. It follows that
the masticatory organ is not to be evaluated accor-
ding to age or growth periods, but that the degree
of maturity and the qualitative functional state must
be integrated as dominant parameters into the
137
Structures - Occlusion - Articulation
Minimizing the significance of occlusion in
current scientific discussions is to be con-
demned, and that current worldwide theories
concerning occlusion and articulation should
be justifiably criticized.
... functional periods. In other words, the
organ should be evaluated according to the
functions required to be performed at a par-
ticular point in time.
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R. Slavicek • The Masticatory Organ
diagnostic procedure. The value and quality of
function becomes the measuring rod for evaluating
the morph. Thus, the concept of "morphology" is
applied according to its actual definition and con-
notation, and not as a synonym for "anatomy".
In embryonic development, phylogenetic aspects
set the tone, although they are subject to environ-
mental influences.
First of all, phylogenetic dominance is observed to
persist and continue postnatally. The term "target-
ed" premature birth, which I use in the chapter on
evolution to denote the ordinary physiological time
of birth, appears to be true from this point of view
as well. The disproportional, rapid development of
cranial volume during hominization was accompa-
nied by simultaneous modification and difficulties
related to the birth passage and by a change in pos-
ture, which made it necessary for the human
neonate to be born early. The viewpoint of reflexol-
ogy supports the concept of regarding the first six
postnatal weeks following normal delivery as an
extrauterine maturation period in embryonic devel-
opment. The time when primitive reflexes play a
governing role approximately encompasses this
period of time (comp Vojta). In modern psychologythis period is also considered as an intrauterine phase.
Genetically, it should be noted that the structural
morphology of dental crowns are mature before they
start to function. This characteristic of the dental
crown led me to the following dogmatic conclusion:
Dental crowns are the determining factors for the
functions of the masticatory organ, only alterable
through damage, non-variable, genetically fixed
structures and fully developed before becoming
functional, in the human organism. Although the
relationship of the crowns to each other, the devel-
opment of roots, the emergence of dental arches
and skeletal development, and also the functional
matrix of the face, are genetically influenced or pre-
determined to a certain extent, they are constantly
subject to ever-changing conditions. The main fac-
tor here is functional necessity.
In the ontogenesis of the individual during the
development of the masticatory organ, a continu-
ous interplay between growth and functional adap-
tation takes place. The functionally adaptive and
developmental processes are coordinated above all
in the regions of the temporo-mandibular joints, in
reaction to the morphology of the erupting hard
structures. The emerging functional patterns are
138
Vojta, V.: Die zerebralen Bewegungsstörungen im Säuglings-
alter. Frühdiagnose und Frühtherapie. Ferdinand Enke
Verlag, Stuttgart 1988
In embryonic development, phylogenetic
aspects set the tone, although they are subject
to encompassing influences.
Dental crowns, are the determining factors
for the functions of the masticatory organ
and only alterable through damage, and they
are also the only non-variable, genetically
fixed structures, in the human organism fully
developed before becoming functional. 
Morphology
Anatomy
Reflexology
Genetics
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striking examples of the adaptive mechanisms of the
stomatognathic system. Didactically, this point of
view should be given importance, because stark,
natural logic helps us to better understand the func-
tionally determined and predetermined temporal
course of "dentition", occlusion and articulation.
In the following, we analyzed the development and
maturation of the masticatory organ from the view-
point of so-called "functional periods". For didactic
reasons we will presume the existence of a future
"normal dentition", although such ideal dentition
usually is the exception rather than the rule.
Nevertheless, the dynamic processes of articulation
can be best understood in the light of so-called
ideal dentition. Based on this information, we will
achieve a better understanding of malocclusion and
dysgnathia.
Normally, the development of the dentition is clas-
sified into:
• Deciduous dentition
• Changing or mixed dentition 
• Permanent dentition
Based on the functions of the masticatory organ,
the following functional periods are found to exist:
• The postnatal period
• The developmental period of deciduous 
dentition
• The functional period of the mature 
deciduous dentition
• The first functional period of a changing 
- mixed dentition
• The second functional period of a changing
- mixed dentition
• The mature dentition
The development of the masticatory organ has
been divided into functional periods, because its
functions are determined by changing require-
ments and new structures. Functional periods are
not to be regarded as periods of growth, but as
periods of adaptation to modifications in form and
function.
139
Structures - Occlusion - Articulation
• Deciduous dentition
• Changing or mixed dentition 
• Permanent dentition
• The postnatal period
• The developmental period of 
deciduous dentition
• The functional period of the mature 
deciduous dentition
• The first functional period of a 
changing - mixed dentition
• The second functional period of a 
changing - mixed dentition
• The mature dentition
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The postnatal period
If we were to separate the first year of life after birth
into four trimenons, the first would be the postna-
tal period. The masticatory organ is marked by
three life-sustaining functions during this time:
• Respiration
• Ingesting food 
• The first primitive vocal communication
Respiration begins immediately and automatically
at birth and is generally associated with a commu-
nicative "wail".
Communication, as a means of conveying informa-
tion to the environment, requires oral speech as the
"transmitter" by which the sounds "AA", "A", "EE"
can be produced. The mother quickly learns to
interpret the signaling language: "AA" stands for
hunger, "A" for pain and "EE" for emotion. At this
time (or earlier), the ear of the newborn already is a
mature receiver and can react to the mother's speech
and sounds (comp. Tomatis) (see ill. 111, p. 141).
Food is ingested under physiological conditions by
laying the "suckling" infant at the mother's breast,
or by offering nourishment in bottles equipped with
a nipple-like apparatus.
The skull of the newborn is characterized by a
marked disproportion between the neocranium and
viscerocranium. Both jaws are edentulous, but the
crowns of the deciduous teeth are already pre-
formed in the dental lamina. The nuclei of the first
permanent molars are also visible on radiographs at
this time; the same is true for the tips of the cusps
(see ill. 112-114, p. 141).
The temporo-mandibular joints are functionally
prepared for the first nutritional phase as "flat" slid-
ing joints. The articular fovea on the temporal bone
is either absent or barely visible; essentially it is a flat
surface. This is the optimal configuration for the
milking action of the infant, as this movement is a
purely protrusive-retrusive one that does not need
to avoid or be controlled by dental structures. The
mandible primarily consists of its horizontal branch;
a mere trace of the ascending branch is seen. The
extension of an occlusal plane constructed in the free
space between the maxilla and the mandible would
pass through the condylar process, as seen in reptiles.
The function of the organ in normal ingestion of
food is more of a milking act than a sucking one.
140
R. Slavicek • The Masticatory Organ
Tomatis, A.: Der Klang des Lebens. Rowohlt Taschenbuch
Verlag, Reinbek 1974
Tomatis, A.: Klangwelt Mutterleib. Kösel Verlag, 
München 1972
Tomatis, A.: Das Ohr und das Leben. Walter Verlag,
Düsseldorf 1977
• Respiration
• Ingesting food 
• The first primitive vocal commu-
nication
Trimenon
The milking function consists of a wide pro-
trusive extension, strong closing, quick,
smooth retraction, and swallowing. 
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Structures - Occlusion - Articulation
141
Ill. 111: Vocal commu-
nication in the first few
months of life.
Ill. 112: The temporo-
mandibular joint and
the future occlusal sur-
face are located on the
same plane. The neuro-
cranium is dominant
and makes it necessary
for the infant to be
born early.
113: This sketch shows
the strong proportional
difference between the
viscerocranium and the
neurocranium.
Ill. 114: This illustra-
tion shows the available
tooth structures at the
time of birth. In many
cases, the bud of the
future permanent molar
reveals calcification.
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The milking function consists of a wide protrusive
extension, strong closing, quick, smooth retraction,
and swallowing. These flat, two-dimensional
movements are ideally suited to the developmental
stage of the organ. The function of milking the
mother's breast, performed by the newborn's "mas-
ticatory" organ ("suckling" is, in fact, incorrect),
wich encompasses the mammary papilla and the
areola with the protrusive action, then closes pow-
erfully and "milks" out the mother's breast in a
retrusive movement. Bichat's sucking pad creates
vacuum during the retrusive movement and there-
by contributes to the pumping effect. The retrusive
movement continues into a physiological, i.e., from
anterior to posterior, deglutition. The direction cor-
responds to peristalsis in the digestive tract. The
protractors (lateral pterygoid muscles),throughout his/her professional life. The vision of
eugnathia may be used as a teaching aid for better
Introduction
The development of the human masticatory
organ, from embryonic development to a
morphologically complete functional unit of
mature permanent dentition and related
structures, is fascinatingly logical, and an
extremely unpredictable event. Function and
dysfunction are very closely related but not
connected with the concepts of eugnathia and
dysgnathia.
One of the most important ideological and
conceptual errors in dentistry is based on the
dogmatic declaration of a fictitious goal,
namely an ideal eugnathia, which is exalted
to the Holy Grail of dental medicine. 
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comprehension of dysgnathias which, in most
cases, function "in spite of the abnormality". Life is
not interested in form but in function.
The central role of the masticatory organ in the
evolution of an individual, in abstract communica-
tion and in the development of the brain connec-
ted with it, is worthy of note.
"Speech makes the brain; the brain makes speech".
This statement of Popper, expressed during a dia-
logue with Lorenz, indicates the importance of oral
communication in anthropogenesis. Popper, an
avowed agnostic, relentlessly continued in this vein.
Referring to the concept of Creation in a dialogue
with Eccles he said, "Man created himself through
his descriptive speech."
The masticatory organ is known for its close somat-
ic connection with the development of the brain.
Its connection with the brain has a psychic 
facet as well. The emotional assessments resulting
from ethical values associated with anthropogene-
sis, the appearance of "self-consciousness" and the
conscious recognition of the difference between
self-protecting egoism and the altruism necessary
for survival of the species, are brain developments
markedly associated with the masticatory organ.
The rather polar balance of the limbic system, up to
this point, was brought into imbalance by the "fall
of man" into anthropogenesis. In the somatic area,
the process of "standing up" and using bipedal 
locomotion created both new responsibilities and
inherent new strategic phylogenic and ontogenetic
problems for the masticatory organ. There followed
an unprecedented dramatic change in the anatomy
of the base of the skull, resulting in a considerably
accentuated development of the maxillo-mandibu-
lar structures, including the dentition. All of these
morphological changes occurred in an extremely
brief period during the phylogenesis of the human
species, and is repeated in the ontology of the first
two years of the life of every human being. Posture
and the masticatory organ have existed in an insep-
arable interdependence since the origin of
mankind.
The anatomy of the human cranium, and especial-
ly the viscerocranium, distinguished by the masti-
catory organ, displays a very high degree of vari-
ability and individuality in terms of skeletal struc-
tures. The positions of the jaw bones relative to the
cranium on the one hand, and the dental arches
within these jaw bones relative to each other on the
12
Popper, K. R., Lorenz, K.: Die Zukunft ist offen
(Das Altenberger Gespräch). Serie Piper, München 1985
Popper, K. R., Eccles, J. C.: Das Ich und sein Gehirn. Serie
Piper, München 1982
"Speech makes the brain; the brain makes
speech". 
"Man created himself through his descriptive
speech."
The rather polar balance of the limbic
system, up to this point, was brought into
imbalance by the "fall of man" into anthropo-
genesis. 
The anatomy of the human cranium, and
especially the viscerocranium, distinguished
by the masticatory organ, displays a very high
degree of variability and individuality in
terms of skeletal structure. 
R. Slavicek • The Masticatory Organ
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other, are characterized by marked differences
between races, as well as, by remarkable differences
between individuals within these races. 
This semantic repetition of individuality in the last
sentence is used to emphasize its importance.
Individuality (the individual is irreproducible, in-
comparable, unique, and therefore different from
anybody else) places a huge question mark behind
the validity of epidemiological studies, which large-
ly ignore the subject of individual differences. This
predisposition of current natural science to reduc-
tionism in the field of medical research for epi-
demiological evidence is challenged, and refuted,
by the existence of the individual.
The concept of "human races" and their differences
deserve emphasis as well as immediate qualifica-
tion. There is only one human "species"! The
human race has a series of ethnic groups within the
one species, characterized by phenotypic differ-
ences.
Everything about the masticatory organ changed
through the genesis of mankind: Its structures,
functions, and its relation to the brain and therefore
to the psyche, and, above all, its assumption of a
central position in the hierarchy of the human
organism. The so-called masticatory organ is, in
conjunction with the brain, the most human of
organs, in terms of construction as well as signifi-
cance. The human masticatory organ has no com-
parison in the long process of evolution, from a
functional point of view. Because of the masticato-
ry organ and the brain, human beings were able to
create an ecological niche, which resulted in their
being in a position to create their own new world.
The dangers and responsibilities associated with
this ability have been covered by various authors.
The masticatory organ, its functions and dysfunc-
tions and their diagnosis and therapy is a fascinat-
ing field and a challenge for the modern dentist.
This organ deserves to be admired and highly
esteemed by "its" dentists. It requires going back 
in his/her mind, turning to and reflecting on the
holistic concept of medicine. It also means turning
away from mechanistic thought without neglecting
the mechanical elements of dental medicine. The
modern dentist must master his/her craft and at the
same time understand the importance of the mas-
ticatory organ for the entire field of medicine.
This book is dedicated to diagnostics and contains
diagnostic information, but let me warn the reader
Introduction
13
Lorenz, K.: Die acht Todsünden der zivilisierten
Menschheit. 18. Aufl., Piper Verlag, München 1985.
Földy R.: Das Arche Noah Syndrom. Nicht alle haben Platz.
Wirtschaftsverlag Langen Müller/Herbig, München 1997
There is only one human "species"! 
The so-called masticatory organ is, in conjun-
ction with the brain, the most human of
organs, in terms of construction as well as
significance. 
The masticatory organ, its functions and dys-
functions and their diagnosis and therapy is a
fascinating field and a challenge for the
modern dentist. 
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and emphasize that collecting diagnostic informa-
tion cannot be an end in itself; it only constitutes
the preliminary step of a diagnosis. Formulating a
diagnosis is not the task of some apparatus or, even
more dangerous, some seemingly logical computer
program, but a deeply human decision, replete
with responsibility.
The purpose of diagnosis is to identify the "disease"
and "cure" it. With this seemingly unpretentious
definition, I am attempting to illustrate the main
problem dealt with in this book, as well as high-
light the erroneous direction of progress in modern
medicine. Diagnosis must necessarily lead to a ther-
apeutic decision, to a "yes or no" regarding therapy.
Thus the diagnosis itself, being a human responsi-
bility, is subject to human fallibility. One of the
weaknesses of currently prevalent opinion within
our social structure is to disregard physician's falli-
bility. More often than not, this leads to a kind of
risk-free, alibi medicine, based on a fear of legal con-
sequences for human fallibility.
For this and other reasons, the path of medicine at
the end of the twentieth century tends to favor
exaggerated diagnostics. The resulting problems of
coordination haveretractors
(temporal muscles and digastric muscles), the
tongue, buccal and labial muscles and the entire
musculature of the floor of the mouth are involved
in this flat, i.e. horizontal plane, movement.
Thus, the natural method of ingesting food by the
infant should be regarded as the first mandibular
movement pattern, which also remains intact later
in the mature masticatory organ. It is the basis of
every mastication pattern and is always demon-
strated in the individual action of mastication.
In physiological breast-feeding, the infant makes
"symmetrical" use of this system by switching from
the right to the left breast (see ill. 115 and 116, p.
143).
If food is ingested from a bottle, no change in posi-
tion is likely to occur. It is governed by the domi-
nant hand of the person feeding the infant. This
results in a characteristic asymmetrical function.
This problem should definitely be discussed with
parents when they are being instructed in this
regard (see ill. 117, p. 143).
In the terminology of the functional physiology of
deglutition, the term "infantile deglutition" is used
to describe a protrusive (pathological) lingual
movement during deglutition. This is misleading,
insofar as regular deglutition in the infant is a cor-
rect, retrusive process.
142
R. Slavicek • The Masticatory Organ
Marie Francois Xavier Bichat 1771–1802
Thus, the natural method of ingesting food
by the infant should be regarded as the first
mandibular movement pattern, which also
remains intact later in the mature masticatory
organ. It is the basis of every mastication pat-
tern and is always demonstrated in the indi-
vidual action of mastication.
"Suckling" is, in fact, incorrect.
Peristalsis
Mastication
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Structures - Occlusion - Articulation
143
Ill. 115, 116: These two pic-
tures show the necessity to
"shift" the baby.
Ill. 117: The risk of develop-
ing asymmetrical function due
to the dominant hand of the
feeder.
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Perinatal problems
For several reasons, the process of birth is laden
with risk for future functions. Modifications in the
female birth canal brought about by the evolution-
ary change in posture to the upright position and
the concurrent increase in the size of the neurocra-
nium led to early birth of the infant, triggered by
hormones. Nevertheless, because of the voluminous
neurocranium, the risk of brain trauma is relatively
high (comp. Vojta). In the event of brain damage,
free brain areas provide good chances of recovery.
Nevertheless, postnatal functional disorders may
occur. The latter must be diagnosed and treated as
early as possible. In the first trimenon, the infant
has so-called primitive reflexes. From a prophylac-
tic point of view, it is important that the physician
as well as the parents of the infant maintain a close
watch on the infant's reflexes. Well-instructed par-
ents examining the infant at regular intervals can
do much to serve as a preventive force for the sys-
tem (see ill. 118-121, p. 145-146).
However, during parturition, the viscerocranium
can also be subject to trauma, above all when, due
to abnormal presentation, it is not protected by
physiological ventral flexion. Therefore, a signifi-
cant part of any functionally oriented anamnesis
of infants and adolescents must also retrospective-
ly consider the history of the parturition. Routine
perinatal check-ups and investigation of the cra-
nium and masticatory organ by a neonatologist
would be helpful.
The postnatal period is marked, functionally, by
the ingestion of food (milking action) as well as by
the beginning of oral communication at the 1st
and 2nd levels of the Bühler-Popper scheme.
At the end of the third month, a changeover from
primarily phylogenetic development to ontoge-
netic development begins. Symphyseal elbow sup-
port is one feature of this period. The head and
face are directed forward. The infant starts to be
prepared for the altered function of the spine at
this time and should be encouraged (see ill. 122-
124, p. 147).
144
R. Slavicek • The Masticatory Organ
Vojta, V.: Die zerebralen Bewegungsstörungen im Säuglingsalter.
Frühdiagnose und Frühtherapie. Ferdinand Enke Verlag,
Stuttgart 1988
Nevertheless, because of the voluminous neu-
rocranium, the risk of brain trauma is rela-
tively high (comp. Vojta). 
Routine perinatal check-ups and investigation
of the cranium and masticatory organ by a
neonatologist would be helpful.
Perinatal
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Structures - Occlusion - Articulation
145
Ill. 118: Initial
steps of re-for-
mation in the
first postnatal
weeks.
Ill. 119: First
independent
efforts of the
newborn in prone
position.
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R. Slavicek • The Masticatory Organ
146
Ill. 120: The new
formation of the
cervical spine in
the first few
weeks.
Ill. 121: Rolling
exercise and
checking reflexes.
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Structures - Occlusion - Articulation
147
Ill. 123: Exercises for the changeover and preparation of the spine.
Ill. 124: Playful training under parental supervision.
Ill. 122: Preparation for independent locomotion according to Vojta.
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Verticalization of the body begins and a distinct
change in reflexes takes place. In vocalization, in
addition to pure vowels, various simple sounds start
to be formed.
At the end of the second trimenon, dentition starts
to develop and the first deciduous teeth erupt (see
ill. 125-130, pages 149-150).
A change in the ingestion of food and in the func-
tion of the organ takes place.
Vocalization becomes more and more of a kind of
echolalia, with the doubling of syllables as the first
signal of "understanding and communicating". The
child learns to use labium-supported consonantal
interruptions in its still mainly vowel-rich speech
(mama, papa).
The third and fourth trimenons are characterized
by the development of locomotion and verticaliza-
tion. Attempts to sit and stand become more inten-
sive. In the time-lapse of ontogenesis, human verti-
calization and the inherent struggle against gravity
takes place. The child passes through uncoordina-
ted wriggling, to crawling and sitting. Standing
and walking occur at the end of this period (see ill.
131-137, pages 151-153).
Exactly at this time, the masticatory organ under-
goes extensive functional modification.
The development of speech, the changeover to true
mastication, the role of the cervical spine as an
organ of support for the head, the coordination of
the shoulder and neck muscles and the develop-
ment and maturation of independent rotation of
the head, dominated by sense organs, by way of
functional "turning towards," - all of these changes
occur at this time (see ill. 138, p. 154).
The dramatic reorganization of the cranial base and
the temporal bone for the now commencing "free-
dom of movement" as a true biped are a fascinating
ontogenetic wonder in terms of rotation and
counter-rotation. At this time the human child
develops in a clearly different way than the primate
one, the two having been similar up to this point.
The conversion to true bipedal locomotion is
extremely significant for the development of the
masticatory organ. From this point on, the free pos-
ture of the head is controlled by several factors.
148
R. Slavicek • The Masticatory Organ
At the end of the second trimenon, dentition
starts to develop and the first deciduous teeth
erupt.
The third and fourth trimenons are charac-
terized by the development of locomotion
and verticalization. 
Echolalia
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Structures - Occlusion - Articulation
149
Ill. 125 (left): The end of the second
trimester, beginning of dentition.
Ill. 126, 127: Generally, the eruption of the
mandibular deciduous dentition takes place
first, followed by the maxillary one.
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R. Slavicek • The Masticatory Organ
150
Ill. 128: The skull at approximately eight months.
Ill. 129, 130: The eruption of the maxillary and mandibular deciduous dentition and
free function of the mandible.
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Structures - Occlusion- Articulation
151
Ill. 131, 132: The first attempts …
Ill. 133: The head and its cervical spine turning to "pay attention".
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R. Slavicek • The Masticatory Organ
152
Ill. 134: Success …
Ill. 135: Rotational ability …
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Structures - Occlusion - Articulation
153
Ill. 136: Goals …
Ill. 137: The bipedal being - the free and moveable head.
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R. Slavicek • The Masticatory Organ
154
Ill. 138: Rotation and counter-rotation, upright stance and the organ of equilibrium.
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Structures - Occlusion - Articulation
The controlling factors are as follows: the inner ear,
the optical system and proprioceptive controls in
the cranio-cervical region. Tilscher postulates cra-
nial articulation as a sense organ. From this view-
point, the overlapping associations between the
masticatory organ and postural problems become
apparent.
During this time it is necessary that the child's
development be carefully observed, as this is the
best time to treat irregular development and diag-
nose functional asymmetry and grave postural
problems. Well-informed parents are a great help
in this task.
As the dentition progresses, close attention should
be given to the development of the dental arches.
The continued differentiation in the formation of
sounds begins to occur after the first year, starting
with the anterior deciduous teeth wavering attempts
to make dentition-supported and dental soft-tissue
supported sounds are made during this time. The
development of speech accentuates and imparts
powerful formative impulses to the system. The
position of the tongue and the dynamic and static
harmony with the facial muscles now form the
masticatory organ.
An absolutely new and previously neglected aspect
of the possibly altered functional development of
the organ has arisen - and must be given due atten-
tion in the future - through the dramatically posi-
tive survival prognosis for premature infants.
Regarding the masticatory organ, the developmen-
tal disorders that might possibly result from pre-
liminary neonatological life-sustaining measures
and the preventive measures that need to be under-
taken in order to avoid subsequent dysfunction are
not yet fully known. Developmental disorders in
the functional area of primary deglutition could, for
example, have an effect on future (faulty) develop-
ment of the masticatory organ.
Comparisons of premature infants (with and with-
out intensive medical care) and those born at term
revealed astounding results: premature infants who
grow under normal physiological conditions have
the best functional diagnostic results (comp.
Stockner). In infants born at term, it is important
to avoid functional disorders related to nutrition.
At this point, improperly handled bottled food can
lead to the first pathologies in the function of the
masticatory organ (dysfunction of deglutition).
155
Tilscher, H.: Das Bewegungssegment der Wirbelsäule im
Blickpunkt der orthopädischen Rückenschule. Medizinisch-literari-
sche Verlagsgesellschaft, Uelzen 1993
Stockner, A.: Die Überprüfung des Funktionszustandes des 
stomatognathen Systems ehemaliger Frühgeburten und Geburten mit
intensivmedizinischer Behandlung in den
ersten Lebensmonaten. Eine Nachuntersuchung im Alter 
von 7 bis 13 Jahren. Dissertation, Univ. Wien 1996
Tilscher postulates cranial articulation as a
sense organ. From this viewpoint, the over-
lapping associations between the masticatory
organ and postural problems become appar-
ent.
The development of speech accentuates and
imparts powerful formative impulses to the
system. 
... the dramatically positive survival prognosis
for premature infants. 
Comparisons of premature infants (with and
without intensive medical care) and those
born at term revealed astounding results: pre-
mature infants who grow under normal phy-
siological conditions have the best functional
diagnostic results.
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The development of deciduous teeth
When the first deciduous teeth (in most cases the
lower incisors) erupt, a rapid shift in function takes
place. The adductors are utilized to a greater
extent; the dental crests are functionally stressed by
solid food and objects. A shift to more solid food
takes place and, consequently, to mastication. This
occurs in most cases in a protrusive position (see ill.
139, left). The functional development of a dento-
alveolar process is accelerated; such development is
primarily subject to the functional influences of the
tongue and labial structures. Pacifiers or thumb-
sucking can disrupt regular morphological and
functional development at this time, causing defor-
mities. Naturally, this also applies to unwarranted
continuation of bottle-feeding. Commonly used as
a means of calming the infant before it goes to
sleep, bottle-feeding leads to oral respiration, which
has a negative effect on the development of the
maxilla and, in addition, may instigate an outdated
type of caries. "Bottle feeding decade" is the new
term to denote the period during which such caries
occurs.
Other dramatic developments take place during
this period: the shift to the upright position, its
strong influence on the cranial skeleton and the
cervical spine, and the beginning of oral communi-
cation through learning the native language.
During the development of deciduous teeth, com-
municative speech, the "mother tongue", develops
to the third level of the Bühler-Popper scheme. The
first signal for this is the child's repetition of sylla-
bles. At this time there is a danger of functional
speech disorders being transferred by the teacher to
the child. Learning a language at this point is based
on imitation. Of significance here is the fact that
(comp. Garliner) oral functions determine form,
i.e., functional speech disorders determine form!
Thus, a structure- or function-based speech disor-
der of the mother (or father) can cause a patholog-
ical form of the functional speech disorder in the
child. The transferred functional disorder may lead
to a structural deformation. The assumption that
dysgnathia is always based on genetic factors is not
true. Therefore, from the viewpoint of system pro-
phylaxis, it is speech that deserves careful observa-
tion. Language is imitation. Learning the "mother
tongue" bears the inherent risk of speech disorders
being passed on to the child by the teacher. It is the
156
R. Slavicek • The Masticatory Organ
Ill. 139: Physiological protrusive direction during growth
Deforming influences at this time, such as
pacifiers or thumb-sucking, can disrupt regu-
lar morphological and functional develop-
ment. 
During the development of deciduous teeth,
communicative speech, the "mother tongue",
develops to the third level of the Bühler-
Popper scheme.
Functional speech disorders determine form!
The assumption that dysgnathia is always
based on genetic factors is not true. 
Garliner, D.: Myofunctional Therapy. W. B. Saunders
Company 1976
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dentist's responsibility to inform parents at this
time, as the advice of a logopedist is sought much
later.
As the dental arches of deciduous teeth become
more fully developed, neuromuscular awareness and
programming become more distinct. The frequent-
ly incongruent size and form of the arch makes it
difficult for the arches to fit together. The system
then decides on the best possible dentition it can
achieve. For this purpose, it may considerably alter
the position of the mandible. The mandible is
adjusted asymmetrically in order to achieve most
optimal function. As a result, the original symmet-
rical form of the mandible may continue to develop
asymmetrically because of function-based adapta-
tion. The adaptive process leads to the skeletal devel-
opment being forced to compensate. Functional
asymmetry results in morphological asymmetry. 
Compensation processes or completed compensa-
tion mechanisms must be detected in the process of
diagnosis, and there must follow a clear distinction
between the former on the one hand,and develop-
mental disorders due to other causes on the other.
Compensation processes are not only transversal in
nature, but are found at all levels. During the
process of development, the organ attempts to
adapt optimally to form, while ensuring that it is
able to execute the functions it is required to per-
form. The goal is always optimal function.
This illustrates the significance of the dentition and
the importance of observing it carefully. The pedia-
trician's role is a very significant one. Any regis-
tered developmental anomalies should be eliminat-
ed at this early point in time, before compensatory
processes start to manifest themselves. The pedia-
trician consulted for this purpose must be able to
depend on the knowledge and understanding of
the referring dentist or orthodontist. From the
viewpoint of prevention, it would be a grave error
to allow such asymmetries to "mature". It should
always be remembered that the form of the
mandible will be the problem, while additional
problems will be created by asymmetrical move-
ments and functional patterns. Orthodontic mea-
sures in a "mature", compensated "dysgnathic"
patient have the potential to de-compensate com-
pensated function and create dysfunction.
157
Structures - Occlusion - Articulation
... risk of speech disorders being passed on to
the child by the teacher. 
The system then decides on the best possible
dentition it can achieve. For this purpose, it
may considerably alter the position of the
mandible. 
Functional asymmetry results in morphologi-
cal asymmetry.
Any registered developmental anomalies
should be eliminated at this early point in
time, before compensatory processes start.
From the viewpoint of prevention, it would
be a grave error to allow such asymmetries to
"mature". 
Dysgnathia
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The first developments in speech
Speech development during this period is a contin-
uation of another significant area of brain develop-
ment, namely the so-called "lateralization" of brain
hemispheres. This means that the brain hemi-
spheres undergo, to a certain extent, a shift in their
center of gravity and responsibilities due to the
demand for a highly developed coordinating func-
tion.
The development of descriptive speech initiates or
deepens the functional asymmetry of the brain and
thereby determines "(one-)handedness". Phylo-
genetically, this development is specifically associat-
ed with hominization. Although predetermined,
the process is characterized by individual learning.
Of course, lateralization also affects the eyes and, in
a particular way, the remaining cranial nerves, espe-
cially the auditory nerves. As mentioned previous-
ly, the development of speech is of great signifi-
cance for the masticatory organ. Early diagnosis of
problems and the correction of functional disorders
are very significant for the development of the den-
tition.
Problems relating to the sleeping
position
In terms of system prophylaxis, the possibility of
the sleeping position being the cause of develop-
mental disorders related to growth must be dis-
cussed with the parents of the neonate. Posture
while sleeping is important not only during growth
but also later, when the causes of dysfunction have
to be located and explained. The individual's pos-
ture while sleeping plays an especially important
role with regard to cranial development in early
childhood. Closely associated with the psyche as an
expression of anxiety are the popular one-sided,
rolled up sleeping position or the face-down
abdominal position. Both are significantly involved
in the development of asymmetries. Timely recog-
nition and correction are important for prophylaxis
of the system.
158
R. Slavicek • The Masticatory Organ
The development of descriptive speech 
initiates or deepens the functional asymmetry
of the brain and thereby determines 
"(one-)handedness". 
Of course, lateralization also affects the eyes.
Posture while sleeping is important not only
during growth but also later, when the causes
of dysfunction have to be located and
explained. 
Lateralization
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Respiratory problems
Respiration is a major factor in the structural deve-
lopment of the dentition. Proportional developmen-
tal disorders between the maxilla and mandible
from frequent or dominant oral respiration lead to
incongruence in the arches. Both, the tongue's posi-
tion and its function are strongly altered in these
cases; the formative impulses to the maxillary arch
are lessened. Problems in respiration also have
repercussions on body posture. These interrelation-
ships were recognized, described and corrected
through system prophylaxis long ago (comp.
Balters). Nevertheless, there still has been no gen-
eral breakthrough in dental concepts in this regard.
The functional periods of mature
deciduous dentition
At approximately two and a half years of age, the
fully developed deciduous teeth achieve maturity.
The bases of the jaws contain the dental arches,
which are rather wide and have no sagittal or trans-
versal compensation curves (see ill. 140 and 141,
right). The extension of the occlusal plane passes
through the condylar process near the articular
trochlea. The mandible is still strongly dispropor-
tional in favor of the horizontal branch. The articu-
lar eminence is minimally developed.
Maximum learning of all the tasks of the future
masticatory organ takes place during this function-
al period. Speech, mastication and deglutition are
in the foreground.
At the same time, the masticatory organ is also
stressed from the parafunctional viewpoint. Most
children in this developmental period are heavy
"grinders". In this extreme learning period, the
child is subjected to strong emotional stresses.
Increasing limitations are imposed on the child's
personality by the constraints of his/her education
towards becoming a "social being". As a result, the
masticatory organ is apparently used as a nocturnal
stress (safety) valve - a normal physical reaction for
balancing aggression. In many cases, the result is
distinct abrasion of deciduous teeth.
159
Structures - Occlusion - Articulation
Ill. 140: Scheme of the full arch in deciduous dentition,
whose functional period continues to the sixth year.
Ill. 141: The dental arches have no compensation curves and
are therefore rather two-dimensional. The joints lie closely
above an altered occlusal plane.
Most children in this developmental period
are heavy "grinders". 
Balters, W.: Neue Ergebnisse der Artikulationsforschung.
Deutsche Zahn-, Mund- und Kieferheilkunde, Bd. 3, H.4,
1936
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R. Slavicek • The Masticatory Organ
During this period the mandible intercuspates with
its dentition mainly in a slightly protrusive posi-
tion. The maxillary and mandibular deciduous
molars generally close distally in a vertical plane
(post-lacteal plane). This is advantageous for the
desired Class I dentition of erupting, permanent
molars, according to several authors. The dental
crowns of the permanent incisors and also those of
the first molars are already fully formed and ready
to erupt. Thus, the morphology of teeth is ready
long before the teeth start to function. Because of
the relatively narrow arch of the child's jaw bases,
there is persistent crowding in the permanent
crowns, which manifests itself in a three-dimen-
sional echelon formation of the dental buds.
Problems in the dentition of deciduous teeth are
common, as the dental arches of the maxilla and
mandible often do not intercuspate congruently.
Orthopedic problems, for instance, i.e., incongru-
ence of the arch, are easily compensated for during
this period through adaptation of functional pat-
terns. The masticatory organ adapts in this reactive
time especially rapidly and strongly to functional
impulses. Future processes are marked by targeted
efforts to achieve function.
Of importance is the fact that functional adaptation
is followed by a phase of structural adaptation,
which is critical during the early developmental
period.In order to achieve proper function, adap-
tive compromises are achieved by modifying the
morphology.
Summary of the functional period of
"deciduous dentition"
This functional period is characterized by the estab-
lishment of all functions of the masticatory organ.
The deciduous dentition is rather two-dimensional;
the functional patterns are flat. The functional peri-
od is marked by strong parafunctional patterns
(comp. Ringel, Slavicek).
The mandible lies slightly protrusive, with a gener-
ally slight frontal overbite, resulting near the end of
this functional period in a so-called "post-lacteal
plane", which favors the position of the erupting
permanent molars in Class I. The first six years of
life are distinguished by a dramatic skeletal effort to
160
Problems in the dentition of deciduous teeth
are common, as the dental arches of the max-
illa and mandible often do not intercuspate
congruently. 
In order to achieve proper function, adaptive
compromises are achieved by modifying the
morphology.
The functional period is marked by strong
parafunctional patterns 
Parafunction
Ringel E.: Die ersten Jahre entscheiden. Verlag Jungbrunnen,
Wien, München, 1987
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"catch up" and a shift in proportion, in favor of the
viscerocranium. Of importance at this time is also
the development of the mandible anteriorly.
It is of interest to follow the development of the
occlusal plane in relation to the changing propor-
tions of the mandible near the end of this function-
al period. The relationship between the horizontal
and ascending branches slowly changes in favor of
the latter, thereby increasing the distance of the
occlusal plane to the temporo-mandibular joints.
The dental arches are, in many cases, not ideally
congruent; intercuspation is occasionally ambiguous.
The first functional period of a
changing dentition
The first permanent molars generally erupt behind
the deciduous molars during the sixth year. At the
same time, there is a substitution of dentition in the
anterior region (see ill. 142 and 143, right). The
permanent teeth are hard structures, introducing a
functional interference into the movement pattern
which, up to this point, was rather free and flat
because of the deciduous teeth. The NMS must
immediately compensate for this through modifica-
tion of the functional pattern. The lingual concavi-
ty of the maxillary central incisors and the approx-
imately simultaneous eruption of the mandibular
incisors limit and determine the protrusive pattern
of mandibular movement (see ill. 144, right). The
movements should not be mechanistically misinter-
preted in terms of catenation, in cooperation with
the temporo-mandibular joint (comp. Kubein-
Meesenburg). At this time the mandibular joints
are not morphologically adapted to a steeper gui-
dance. The NMS only limits the movement pattern
to the front. In these anterior movements, the front
teeth are recognized and accepted as obstacles, and
avoided (see ill. 145-149, pages 162-163). This
does not occur however, as a coordinated and
dependent movement on the guidance surface, as
in a crank mechanism. The special proprioceptive
role of the front teeth will be discussed later.
The eruption of the first permanent molars (see ill.
150 and 151, p. 164) behind the deciduous denti-
tion definitely alters the lateral and retral patterns
of the CNS at this early stage. With the eruption
161
Structures - Occlusion - Articulation
Ill. 142: Scheme of eruption of permanent teeth.
Ill. 143: The first molars erupt behind the deciduous dental
arch, the anterior teeth "change".
Ill. 144: The permanent incisors limit the functional space
anteriorly with their arrangement.
Catenate
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R. Slavicek • The Masticatory Organ
162
Ill. 146: The mandibular anterior teeth are arranged slightly vertical to the occlusal axis of the mandible, the dento-alveolar process
develops accordingly.
Ill. 145: This functionally adapted limit is complemented by the structural adaptation of the developing articular eminence.
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Structures - Occlusion - Articulation
163
Ill. 147: Problems in the dentition during this functional period should be taken seriously.
Ill. 149: Crossbite and anterior deep bite must be recognized and treated early.
Ill. 148
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and arrangement of the first permanent molars and
front teeth, a completely new morphological prin-
ciple enters the system. Genetically predetermined,
the new morphology controls functional processes
and the neuromuscular system must adapt to the
new arrangement.
At this time, careful observation of the erupting
molars by the dentist is very important. If the
mandibular molar erupts in proper relation to the
upper molar, with a normal occlusal interdigitation,
then the morphology of the two teeth will be fully
suited to fulfill their four main functions (see ill.
152-167, pages 165-167), namely laterotrusive
guidance, retral protective function, bolus trans-
portation with food processing, and protection of
soft tissues (cheek, tongue). If the molars erupt
divergently, the system will still attempt to achieve
optimal function. Faulty relations give rise to com-
pensatory measures, which may lead to dento-alve-
olar proportional and directional modifications and
also to asymmetries. These occurrences should not
be evaluated as pathologies, rather they should be
regarded as functional adaptation mechanisms.
Of interest now is the increasing differentiation of
the mandible. Through the development of the
ascending branch, the occlusal plane distances itself
from the joint. The increasing distance (DPO =
distance to plane of occlusion) leads to the develop-
ment of a distinct articular eminence; the function-
al condylar track on the eminence becomes more
steeply inclined. This increase in inclination is to be
regarded as an adaptation to the altered form of the
mandible as well as to the structures of the first per-
manent molars and the permanent anterior teeth. 
If the shape of the arch is apparently asymmetrical,
the individual has occlusion problems on one side,
or if the right and left inclinations of the occlusal
plane differ during this phase, there is a risk of
asymmetrical structural maturation of the articular
eminence. Obviously different condylar track incli-
nations are problematic from a therapeutic point of
view, especially during late treatment of the sys-
tem, if the dentist wants to achieve satisfactory and
stable functional results. It is the dentist's responsi-
bility to diagnose and treat the developments as
early as possible.
It is especially important to observe the child's body
and head posture at this time. Incorrect posture
inevitably influences the development of the mastica-
tory organ. Incorrect posture at school, while writing
164
R. Slavicek • The Masticatory Organ
Ill. 151: The solidly structured occlusal surface of the first
permanent molars are indicative of an entirely new morpho-
logical concept.
Ill. 150: The lingual concavity of the mandibular front forms
the controlling anterior limit of functional space. There is no
direct morphological dependence on the temporomandibular
joint.
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Structures - Occlusion - Articulation
165
Ill. 152 left: At
the beginning of a
normal dentition,
the mesio-buccal
cusp of the
mandibular molar
guides laterally on
the inclined mesio-
buccal cusp of the
maxillary first
molar.
Ill. 153 right: The
mesio-buccal cusp
guides laterally
against the mesio-
buccal cusp of the
maxillary molar.
Ill. 154 left: The
maxillary first
molar provides a
place for the disto-
buccal cusp of the
mandibular first
molar on its trans-
verse crest.
Ill. 155 right: The
distal slope of the
disto-buccal cusp
of the mandibular
first molar serves as
a retrusive gui-
dance control for
the protrusive 
position of the
mandible.
Ill. 156 left: The
sturdy buccal cusps
of the first molar
distinguish the
soft-tissue relation
to the cheek.
Ill. 157 right: This
complete image of
the morphological
detailsof the max-
illary first molar
demonstrates its
functional impor-
tance.
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R. Slavicek • The Masticatory Organ
166
Ill. 158 left:
The high lin-
gual cusps of
the mandibular
molar prevents
damage to the
tongue during
mastication.
Ill. 159 right:
The overall rep-
resentation of
the mandibular
first molar with
significant
dynamic details.
Ill. 160 left:
Defined contacts
on the mandibu-
lar molar.
Ill. 161 right:
Defined contacts
on the maxillary
molar.
162: The molar
relation in a
"transparent"
scheme.
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Structures - Occlusion - Articulation
167
Ill. 166: The field of movement is changed by rota-
tion.
Ill. 167: In this functional period, the final arrange-
ment of the front and the first molar dictates the
dynamics of mandibular movement. The teeth shad-
ed in gray are not extant at this time, but are still a
part of the deciduous dentition.
Ill. 163: The movement pattern of the maxillary
molar to the mandible.
Ill. 164: The predominant spectrum of movement of
the mandibular molar to the maxilla.
Ill. 165: Structure dictates pattern.
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and reading, is frequently involved in the develop-
ment of dysgnathias. Writing, reading and listen-
ing are closely associated with the lateralization of
the brain. In cultures with horizontal writing styles,
congenital alexia (dyslexia) is a problem that affects
posture and the form of the viscerocranium. It is of
paramount importance to consider the dominant
ear and the dominant eye when selecting a seat for
the child in the classroom. The head turns the do-
minant "receivers" to the "transmitter", i.e. the
teacher. Static seating plans in the classroom are
entirely inappropriate from the viewpoint of system
prophylaxis.
In the first period of the changing dentition, the
function of speech matures fully; the arrangement
of the anterior arch is strongly subjected to the
functional influences of speech. Anomalies of lan-
guage lead to specific stresses and to the develop-
ment of particular muscle patterns. Phonation is
fully developed by the end of this period. This
includes the characteristic vowel and consonantal
sounds, along with the gutturals, which are labial-
supported, dento-labial-supported, dento-lingual
supported, dentition-related or dentition-support-
ed. The gutturals are frequently conveyed into the
anterior palatal-lingual region (see ill. 168, left).
The arrangement of the dental crowns and that of
the roots of the anterior mandibular teeth follow
the closing axis principle. Accordingly, the roots do
not develop in a straight line but in a slight arc, fol-
lowing the slow verticalization of the system.
While the vertical dimension increases the distance
to the articulation increases, the angle of inclination
of the crowns changes and the curves of the devel-
oping roots follow the closing axis principle (H.
Page) (see ill. 169-174, pages 169-170).
Naturally, this development can be viewed three-
dimensionally. The morphology of the crowns is
determined by genetic factors. The form of roots
and even the entire dento-alveolar complex are
subject to permanent influences. This means that a
fully mature asymmetrical dysgnathia will most
likely have an asymmetrical root morphology. This
is an additional problem in late treatment. Orthlieb
describes in the illustration an angle of difference
from the sagittal view, which is noteworthy from a
dynamic-static viewpoint (see ill. 175, right).
Functionally, an entirely different anterior principle
emerges when the permanent anterior dentition
erupts. From this point on, they control mandibu-
168
R. Slavicek • The Masticatory Organ
Ill. 168: Incisors and anterior palatal structures are important
for the formation of speech, and are also subject to formative
influences.
The arrangement of the dental crowns and
that of the roots of the anterior mandibular
teeth follow the closing axis principle. 
The morphology of the crowns is determined
by genetic factors. The form of roots and
even the entire dento-alveolar complex are
subject to permanent influences. 
Page, H. L.: The Occlusal Curve. Dental Digest 
S. 19–22, 1952
Orthlieb, J. D.: Intérêt de la Courbe de Spee dans la Recherche
d’un Plan d’Occlusion en Prothèse Fixée. Thèse de Doctorat en
Sciences Odontologiques, Aix-Marseille 1983 
Legasthenia
Dyslexia
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Structures - Occlusion - Articulation
169
Ill. 170: The development of the mandibu-
lar dento-alveolar process also follows the
closing axis principle. However, it should
be noted that the central point of dento-
alveolar compensation is exactly at this site.
Ill. 169: The mandibular incisor and its
slight orientation to the occlusal axis.
Ill. 171: The arrangement of the maxillary
front teeth takes place predominantly
under the functional influence of soft tis-
sues, above all, by the lower lip. Speech is
also a dominant factor here.
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R. Slavicek • The Masticatory Organ
170
Ill. 173: The line of stress to the optimal
absorption of pressure from the sagittal
view.
Ill. 172: The molars are arranged, deviat-
ing from Page's rule, not vertical to the
occlusal axis, but having a deviating angle
greater than 90 degrees.
Ill. 174: The closing axis principle is illus-
trated in this overlay of Posselt's scheme.
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lar movements proprioceptively by means of the
normally occurring positive overbite of the maxil-
lary incisors over the mandibular ones. The anterior
teeth are strictly avoided during mastication, as will
be more clearly explained in a later section. This
avoidance mechanism is initially a functional one,
under muscular control, but is rapidly replaced by
structural adaptation at the temporal bone and the
mandible. An increasingly inclined articular emi-
nence begins to develop; simultaneously, the
mandible undergoes continuous change in form and
proportion. During this period of verticalization, the
ramus develops individually, decending the body of
the mandible away from the condyle, which
becomes equally distanced from the occlusal plane.
The maxilla develops transversally, especially in the
posterior region, due to the increased width of the
neurocranium. This continues until beyond the end
of the functional period, bringing about an alter-
ation in the transversal inclination of the occlusal
table of the molars. The mandible adapts and is
remodeled to the maxilla. The anterior arch devel-
ops especially in the lateral incisor region, function-
ally inter-dependent on molar function, and vice
versa.
This period is characterized by strong development
and by increased inclination of the sagittal condylar
track. The transversal condylar track, or Bennett
movement, is characterized individually by inter-
relationships between molars and the anterior arch;
the muscle pattern of mandibular movement
adapts to dental morphology and its spatial pattern
and inter-relationships. Naturally, the adaptation
also takes place in the absence of ideal dental or jaw
relationships, but in such an event the adaptation
occurs in accordance with the existing dentition,
not in keeping with the "normal" pattern of denti-
tion.
During growth, the system attempts to compen-
sate functionally and structurally for dysgnathic
dental or jaw relationships. This applies to the
dento-alveolar region, as well as to development in
the temporo-mandibular region.
171
Structures - Occlusion - Articulation
Ill. 175: In one of his later works, Orthlieb determines a "dif-
ference" angle, which diverges from Page's rule in the lateral
aspect. This will be discussed later.
The maxilla develops transversally, especially
in the posterior region, due to the increased
width of the neurocranium. 
The mandible adapts and is remodeled to the
maxilla. 
The transversal condylar track, or Bennett
movement, is characterized individually by
inter-relationships between molars and the
anterior arch.
During growth, the system attempts to com-
pensate functionally and structurally for dys-
gnathic dental or jaw relationships.Enlow D. H.: The Human Face: An Account of the Postnatal
Growth and Development of the Craniofacial Skeleton. Hoeber
Medical Division, Harper & Row New York, 1968
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The second functional period of the
changing dentition
In conjunction with the eruption and established
pattern of premolars, a more inclined, lateral gui-
dance principle is introduced into the functional
pattern of the dentition. In other words, this 
period is characterized by a new morphology (see
ill. 176-180, p. 173).
The morphology of premolars, especially that of
the first, is important for the final dynamics of lat-
eral, retrusive and protrusive mandibular move-
ments. Extractions in this region should be viewed
with great caution, both from the orthodontic and
functional points of view, and should only be
undertaken after long deliberation and for a good,
well established reason. If possible, extractions
should only be performed after the end of the sec-
ond functional period. "Good reason" most certain-
ly does not include secondary crowding brought
about by the early loss of deciduous teeth.
Extractions in the anterior region are generally con-
traindicated, even in cases of primary crowding, as
the reason for the lack of space often lies in the pos-
terior portion of the arch. Precise diagnosis, careful
therapeutic planning and solid grounds are prere-
quisites for the decision to extract.
With the eruption of premolars, the masticatory
organ enters a preliminary stage of maturation.
The first maxillary premolar is characterized by a
steep, laterotrusive guidance principle; this tooth
now assumes dominance over the character of trans-
versal function. It also exercises important proprio-
ceptive retral control through its practical root mor-
phology and its strategic position in the arch.
Simultaneously, the anterior portion of the arch
matures, and the small maxillary incisor adapts
functionally to the first premolar under its antero-
lateral control. The joint morphology reaches a
stage of pre-maturity and adapts to the required
function. Asymmetrical relationships are counter-
balanced by functional asymmetries.
The temporo-mandibular joint has now achieved at
least 90% of its full development, at the level of the
articular eminence. Its very rapid adaptive capacity
during the first years of development is markedly
slowed down, but is still present. This capacity is
maintained throughout life, albeit to a much lesser
extent.
Observing the morphology of the temporomandibular
joint and the first premolars on X-ray overlays from
172
R. Slavicek • The Masticatory Organ
Extractions in this region should be viewed
with great caution, both from the orthodontic
and functional points of view.
The temporo-mandibular joint has now
achieved at least 90% of its full development,
at the level of the articular eminence.
proprioceptive
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Structures - Occlusion - Articulation
173
Ill. 176-179: These illustrations document the situa-
tion at this point in time.
Ill. 177
Ill. 178 
Ill. 180: Molar and second premolar as a functional
unit.
Ill. 179
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R. Slavicek • The Masticatory Organ
the axial view, one notices the practical dynamic
harmony in these regions (see ill. 181-187, pages
175-176).
Psychic stresses at this age are common. Mentally
induced bruxism is, therefore, widespread and
understandable. From a medical viewpoint, the
masticatory organ system is suitable for serving as
an occasional psychological stress safety valve.
Evaluating the effects of this parafunction on the
masticatory organ and its structures is of decisive
importance.
In this functional period, the premolars assume lat-
erotrusive and retrusive protection for a fairly long
period of time. Temporary indications and symp-
toms of dysfunction are likely to appear on a large
scale. This is due to changes in an extremely com-
plicated functional pattern, in addition to increa-
sing psychic stresses during the prepubescent and
pubescent periods.
The inclinations of the premolar buccal cusps as lat-
eral gliding and guiding elements are morphologi-
cally steeper than those of the first molar, and take
over lateral control from the latter. Thereby, lat-
erotrusive control shifts more anteriorly. In regular
development, the anterior arch matures from this
point to its final functional element, while the lat-
eral incisors adjust with the mandibular anterior
arch in group function to the first maxillary pre-
molar, which frequently erupts first. The maxillary
first premolar can (should) also assume a retrusive
protection function, especially in the presence of a
skeletal Class II with protrusive intercuspating
mandibular teeth.
The retrusive control and guidance described above
in the classical sense acts as a compensation mech-
anism in the presence of a tendency to mandibular
retrognathia. However, a precondition is early
eruption of the mandibular permanent canine. A
significant portion of the ability to build up retru-
sive contacts is located in the root morphology of
the maxillary premolars. A special factor in the
compensation of a skeletal Class II is the special
arched form, typical for Class II/1. The arches have
the typical shape of a lyre, thereby creating nar-
rowness in the anterior of the arch, which sets the
maxillary premolars as retrusive controls to the
mandibular canine.
Under normal conditions, the incisal edges of the
superior front arch are arranged functionally to the
lower lip. If the axis is correctly placed, the lower
lip "stops" the eruption of the maxillary front teeth
174
Psychic stresses at this age are common.
Mentally induced bruxism is, therefore, wide-
spread and understandable. 
In this functional period, the premolars
assume laterotrusive and retrusive protection
for a fairly long period of time. 
The inclinations of the premolar buccal cusps
as lateral gliding and guiding elements are
morphologically steeper than those of the
first molar.
The retrusive control and guidance described
above in the classical sense acts as a compen-
sation mechanism in the presence of a ten-
dency to mandibular retrognathia. 
Compensation
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Structures - Occlusion - Articulation
175
Ill. 181-184: Computerized tomographs illustrating the root strategy, the incision is selected parallel to the occlusal plane.
Ill. 183, 184: In a rather apical incision, note the interesting detail of the mesio-buccal roots of the first molars, as a separate unit
with two canals, appropriate to the premolar root morphology.
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R. Slavicek • The Masticatory Organ
176
Ill. 185: The same incision, showing the intercuspation of the
central cusp of the first maxillary molar in the cavity of the
mandibular molar. The transfer of force takes place in the
palatal root and thereby in the palatal structures.
Ill. 186: This illustration of the mesio-buccal root of the first
maxillary molar shows the transfer of force to the mandibular
zygomatic crest during stress on the buccal cusp in eccentric
control.
Ill. 187: The red arrows show the vector of the dento-alveo-
lar processes and the teeth.
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Structures - Occlusion - Articulation
177
Ill. 188: The soft tissues stabilize the front. Ill. 189: The course of the lower lip determines the course of
the incisal edges of the front.
Ill. 190: The cavity of the ascending branch and the distance of the joint to the occlusion determine the character of the sagittal and
transversal sphere of occlusion (DPO, according to Orthlieb).
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and determines the esthetic course of the incisal line
(see ill. 188 and 189, p. 177).
The temporo-mandibular joint adapts to the
altered functions through additional inclination of
the eminence. Condylar growth and remodeling
change the proportions of the mandible and the
position of the occlusal plane to the joint. The
development of individual compensation curves is
necessary in order to allow for a uniform functional
distance of dental arches (see ill. 190, p. 177).This
means that the increasing distance of the temporo-
mandibular joint from the occlusal plane is com-
pensated for by the increasing sphericity of occlu-
sion.
The third functional period of the 
changing dentition
The last building block in the changing dentition is
the substitution of deciduous teeth by the perma-
nent canines. In a regular arrangement, an individ-
ually dominant guidance principle for the articula-
tion emerges (see ill. 191-192, p. 179). Because of
its crown length and steep lingual surface, the
canine, reintegrated into the upper row through
hominization, is now suited to assume control of
guidance as the dominant element (see ill. 193-
197, pages 180-181).
The functional pattern is again narrower and stee-
per anteriorly. In the guidance pattern there is a lat-
eral disocclusion of the previous guidance elements.
In protrusive gliding guidance, the mandibular first
premolar takes over the stress on the front during
protrusion against the distal fossa of the maxillary
canine. However, this only applies to the regular
bite.
With the eruption and arrangement of the canines,
the steepest morphological principle in the "oral"
functional area begins. The final stage of the dento-
alveolar growth process applies to both, the anteri-
or arch and the gradually developing final arrange-
ment of the supporting zone in the lateral region,
along with the second permanent molars.
The individual spherical model of the dentition
matures, depending on the skeletal principle of the
mandible. The optimal Curve of Spee is achieved
for the masticatory organ. The temporo-mandibu-
lar joints adapt to this situation, by forming the
178
R. Slavicek • The Masticatory Organ
The functional pattern is again narrower and
steeper anteriorly. 
Huber, E.: Evolution of Facial Musculature and Face Expression.
The John Hopkins Press, Baltimore 1931
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Structures - Occlusion - Articulation
inclinations of the articular eminences in concert
with the anterior guidance components.
In this stage of maturation, a functional fine-tuning
of the system within the functional determinants of
the masticatory organ takes place. The transversal
compensation is distinguished by an antero-
posteriorly increasing sphericity. Maxillary and
mandibular dentitions may, but need not necessar-
ily, show equal transversal spherical behavior.
It is to be noted that the morphology of the second
molars develops in very different and individual
forms. The eruption of the maxillary second molar
has, as a rule, transversal emphasis; the occlusal
surface is strongly inclined to buccal. Therefore, in
a normal dentition, it is generally the mesio-palatal
(often alone) cusp of the maxillary second molar
that intercuspates in the central fossa of the
mandibular second molar. Thereafter, continued
maturation can, but need not necessarily, lead to an
uprighting into occlusion (ill. 198, p. 182).
In this stage, as a final stage of development, the
masticatory organ attempts to optimally adjust to
all of the functional demands. The individual, orig-
inal situation has differentiated and becomes less
important, because all of the completed and ongo-
ing developmental processes have the goal of
obtaining eufunction, which may also be associated
with the appearance of a "dysgnathia". It follows
that eufunction and dysgnathia are not necessarily
antithetic. This is a significant aspect of the
approach needed to deal with malocclusion. The
patient's oral functional state must be carefully con-
sidered if orthodontic corrective measures are to be
applied at this point in time. Any orthodontic mea-
sure applied to correct abnormal jaw relationship
conditions may induce a new and extreme adaptive
mechanism. The dysgnathic system has already
adapted to eufunction. Therapeutic measures must
be carried out with exact knowledge of the adaptive
mechanisms. This applies above all to mature
asymmetries which, in most cases, result in func-
tional and structural asymmetries in the temporo-
mandibular joints.
The mandible develops to its final mature skeletal
proportions and the dento-alveolar compensatory
processes adapt to the offered, thereby presenting,
functional patterns. The spatial arrangement of the
occlusion is fixed and final when the second molars
erupt (ill. 199-206, pages 184-186).
179
Ill. 191: The canine completes the maxillary anterior arch and
emerges as the dominant and steepest element of occlusion.
Ill. 192: In conjunction with the canine dentition, the second
molar erupts in the back molar region.
Eufunction
Eugnathia
Hüls A.: Kiefergelenke und Kaumuskulatur im Computer-
tomogramm. Vergleichende klinisch-röntgenologische
Untersuchungen zu Funktionsstörungen im stomatognathen System.
Dissertation d. Med. Fakultät Tübingen, 1981
The spatial arrangement of the occlusion is
fixed and final when the second molars erupt.
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R. Slavicek • The Masticatory Organ
180
Ill. 194: Beginning eccentric movement laterally restricts the free space …
Ill. 193: The canine in normal dentition, the inter-coronal free space is worthy of
note.
Ill. 195: … and shifts by "rolling" slightly outwards.
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Structures - Occlusion - Articulation
181
Ill. 197: After their return, the contact of the mandibular to the maxillary canine lies far mesial on the marginal crest of the maxil-
lary canine or even against the marginal crest of the lateral.
Ill. 196: All incisors on the same side disocclude when they reach the canine tips.
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R. Slavicek • The Masticatory Organ
182
Ill. 198: The maxillary second molar emerges normally in a buccal direction in the occlusion, the mesiolingual grinding cusp inter-
cuspates in the central groove of its namesake on the contralateral side. Often, no contact takes place on the buccal aspect.
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Depending on the developments in the ascending
branch, an individual Curve of Spee compensates
for the increasing distance of the lateral region,
thereby maintaining the efficiency of mastication.
The inclination of the dento-alveolar region from
the transversal view also has a compensatory sphe-
rical character. As a rule, the flexion radius of the
Wilson curves are antero-posteriorly smaller; the
transversal inclination of the occlusal table in the
posterior area increases.
The discussion on changing dentition
The first stage of the functional periods is charac-
terized by the eruption of the first permanent
molars behind the deciduous dentition and their
"searching" inter-digitation, and by the eruption of
the mandibular and maxillary front teeth. This
results in a narrowing of the functional pattern
from the front and the side. The adaptation is mus-
cular at first, then structural, because of the
increased inclination in the articular eminence.
Thus, alterations in the form of the condylar
process and the articular eminence occur as a result
of altered functional conditions. Retral control of
mandibular movements is carried out in regular
inter-digitation by the first molars on the transver-
sal ridge of the maxillary sixth tooth (1st molar),
thus maintaining a favorable protrusive position for
the mandible. Significant individual vertical deve-
lopment takes place, both in the dento-alveolar
region and in the ascending branch of the
mandible.
In the second period, primarily the first maxillary
and mandibular premolars erupt. The position of
the mandible is still distinctly protrusive, depending
on growth. The maxillary anterior arch and the pre-
molars form a functional unit. The new functional
patterns are manifested, both structurally and mor-
phologically, in the temporo-mandibular joint.
During the second developmental phase of the
changing dentition, the course of the lower lip dis-
tinguishes the line of the incisal edge of the maxillary
front teeth. The decreasing sphericity of the occlusal
plane compensates for mandibular ramus growth.
The eruption of the canine in the third functional
period introduces the steepest lateral guidanceele-
ment into the occlusal principle. It also brings pro-
183
Structures - Occlusion - Articulation
The adaptation is muscular at first, then
structural, because of the increased inclina-
tion in the articular eminence. 
Graf Spee, F.: Die Verschiebungsbahn des Unterkiefers am
Schädel. Arch. Anat. Physiol. 16: 285-294, 1890
The eruption of the canine in the third func-
tional period introduces the steepest lateral
guidance element into the occlusal principle. 
Sphere
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R. Slavicek • The Masticatory Organ
184
Ill. 199: Lateral view of a model in normal dentition, from the right.
Ill. 201: Cusp alignment from buccal, from the right.
Ill. 203: The lateral view of the right side shows the distinct concavity of the cusp, its
overall course is incorrectly designated the Curve of Spee.
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Structures - Occlusion - Articulation
185
Ill. 200: Lateral view from the left.
Ill. 202: Cusp alignment on the left side. Note the slight asymmetry in the inclination
of the premolars and molars in this appealing normal dentition.
Ill. 204: In this view of the left side, a slight asymmetry is also noticeable. In this
view, the course of the cusps up to the canine tips corresponds to Spee's original defini-
tion, according to which they are assigned to the lateral segment.
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R. Slavicek • The Masticatory Organ
186
Ill. 206: In the above model, the "hanging" lingual cusps are recognizable, on which the absorption of force takes place in closed
jaw position.
Ill. 205: The view from the front shows the convex course of the mandibular front edges, which change over to the concave course
of the Curve of Spee only after the canine or the first premolars.
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trusive relief for the anterior arch by means of its
distal fossa. The mandible attains skeletal maturity.
The second molars contribute to the spherical shape
of the occlusal plane. The temporo-mandibular
joints adapt both functionally and morphologically
to the final situation.
Mature, complete dentition
The skeletal foundations of the dentition, i.e., the
relations of the jaw bases to each other, are in no way
uniform, but vary widely. Nevertheless, they are
counterbalanced in such a way during growth by
compensatory processes, especially in the dento-alve-
olar region, that a condition very near to a normal
dentition-occlusion can be effected. Compensatory
growth in the joint and the functional remodeling of
structures take place. This creates a jaw relation by
which the temporo-mandibular joints are placed
near or at their physiological retral border, in a 
maximum intercuspal position.
It should be noted that this mature dentition is the
result of many detailed mechanisms. The genetical-
ly determined basic relations of skeletal bases are
subject to a variety of external influences and func-
tional coincidences. It should be remembered that
the goal of the development of an organism is to
achieve optimal function. From the viewpoint of
the masticatory organ, this is a functionally capable
occlusal relationship within the erupting dentition.
This, apparently, is the so-called regular bite.
Previously, occlusion was approached from an over-
all viewpoint while details of the dentition were not
discussed. This is an obvious diversion from the
common didactic path, which leads through a
detailed description of the morphology of the indi-
vidual tooth towards an overall assessment. This
frequently results in a well-known phenomenon
known as "viewing the tree very carefully but over-
looking the forest". If we were to describe occlusion
in maximal intercuspation, the tooth morphology
of a dentulous person would determine the object
of our description. The dentition fits best in Class I
with a regular bucco-labial overbite. This ideal of
complete matching or coupling, which is purpor-
ted to be a regular bite, is by no means the "rule"
but rather an ideal, and generally the exception.
187
Structures - Occlusion - Articulation
The skeletal foundations of the dentition, i.e.,
the relations of the jaw bases to each other,
are in no way uniform, but vary widely. 
The genetically determined basic relations of
skeletal bases are subject to a variety of exter-
nal influences and functional coincidences. 
The dentition fits best in Class I with a 
regular bucco-labial overbite. This ideal of
complete matching or coupling, which is pur-
ported to be a regular bite, is by no means
the "rule" but rather an ideal, and generally
the exception.
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Nevertheless, it is important to regard a Class I
dentition as a reference point for studying the den-
tition of the patient on hand, in order to describe
deviations from the normal condition.
The definition of normal dentition is by no means
uniform and is frequently influenced by profession-
al speculation. The term Class I originates from
Angle, a classification with which he was attemp-
ting to help identify and describe normal versus
abnormal jaw(s) and tooth relationships (disg-
nathia). Angle's classification was quickly attacked
and denounced as unsuitable. However, the fact is
that it still is the most widely taught and used clas-
sification.
The so-called normal dentition, which approxi-
mates Class I of Angle's classification, seems to rep-
resent the best dentition principle from the sagittal
view. Teeth simply match up best in this Class I
relationship; the upper and lower arches also har-
monize well. In normal dentition, the arch rela-
tionship is characterized by a buccolabial overbite
from the upper to the lower arch.
Compensation 
mechanisms
From a variety of basic skeletal principles that apply
during growth, the organism attempts to reach this
optimal dentition, or at least a close to normal den-
tition model. For this purpose, it makes use of so-
called compensatory mechanisms. The three main
mechanisms for compensating skeletal discrepan-
cies are as follows:
Dento-alveolar compensation
Vertical compensation
Articular compensation
188
R. Slavicek • The Masticatory Organ
Angle, E. H.: Behandlung der Okklusionsanomalien der Zähne.
Angle’s System 630. S 80. Hermann Meusser (7. Auflage),
Berlin 1908
• Dento-alveolar compensation 
• Vertical compensation 
• Articular compensation
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Structures - Occlusion - Articulation
Dento-alveolar compensation
Dento-alveolar compensation is the tendency of the
dento-alveolar unit to set up an optimal, or at least
acceptable, occlusal relationship through modifica-
tions in inclination and height. The tendency of
development of the alveolar process is, of course,
three-dimensional, but it can be seen most instruc-
tively and distinctly in the relational arrangement
of the front teeth in a sagittal display (ill. 207,
right). This compensatory tendency can also be
established and seen in the region of the laterals.
Vertical compensation
Vertical compensation varies the final distance
between the maxilla and mandible. Because of the
required rotation of the mandible, the skeletal rela-
tionship of the two bones is also altered. Of course,
vertical facial developments necessitate modifica-
tions in the dento-alveolar region.
Articular compensation
Articular compensation is a continuous, lifelong,
adaptive process of the mandibular joint to alter-
ations in occlusal requirements. In children, during
the maturation periods of the masticatory organ,
and in young adolescents, it is a significant factor in
the occlusal position of the occluso-articular rela-
tionship.
Diagnostically, articular compensation can be clear-
ly seen in the sagittal border scheme designed by
Posselt. Posselt graphically compares the occlusal
position of maximal intercuspation (ICP) to an
occlusal retral contact position (RCP), which is the
retral physiological margin reached in the closing
rotation of the mandibular joints. The situation at
the margin is determined by the ligamentary retral
borders of the joints and also by the first occlusal
contact, which takes place in a terminalclosing
rotation. In most adults, a difference between ICP
and RCP is found. However, in terms of quantity
and quality, the discrepancy in the joint region is
generally only a few tenths of a millimeter (ill. 208-
210, p. 190).
The didactic exaggeration, in much of the litera-
ture, of the customary schemes for sagittal diffe-
rence has led to gross misunderstandings. These
189
Ill. 207: In this specimen, the relationship of the dento-alveo-
lar process of the region and also the contacts in the lateral
tooth area are clearly seen.
Slavicek, R.: Die funktionellen Determinanten des Kauorgans.
Habilitationsschrift, Wien 1982
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R. Slavicek • The Masticatory Organ
190
Ill. 209: The sagittal difference for the majority of the population lies in the range of 0.3 mm.
Ill. 208: The human mandibular joints show transversal deviations between ICP and RCP, which amount
to only hundredths of a millimeter.
Ill. 210: The vertical difference is also less than 0.3 mm for a large percentage of adults.
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exceptions, very important for diagnostics and
therapeutics, are those very few significant indivi-
duals who display the true "articular compensation"
of a relative skeletal distal relationship of jaw bases
(skeletal Class II). These patients can achieve qua-
litatively good or acceptable intercuspation by
means of a permanent protrusive position of the
mandible. Their Posselt scheme is distinctly diffe-
rent from the majority of individuals, who have no,
or very little, discrepancies between RCP and ICP.
The temporo-mandibular joint has the lifelong
ability to adapt to changing occlusal requirements.
The close relationship or conformity of a physiolo-
gical, unforced retral joint position with a maximum,
but unforced, dental relation is desirable, as the 
muscularly controlled dynamics of the mandible
are primarily directed anteriorly or anterolaterally.
Modifications take place throughout life in all
structures. Thus, from a biological viewpoint, a
healthy system is stable within the joint. Based on
long-term investigations of convalescent patients,
Kulmer established that the position of the tem-
poro-mandibular joints maintains an exceptionally
stable relation to occlusion and articulation,
although the position of teeth and the dental arch-
es change distinctly over a prolonged period of
time. This is only possible by means of permanent
and continuous adaptive processes in the joint. It
also shows, however, that an unforced retral joint
position in equilibrium with the occlusion is a bio-
logically acceptable relationship and a reality.
This is not contradicted by the deviations published
by Celenza. His results show strikingly negligible
differences between a retral border as the initial
position on the one hand, and the "current" situa-
tion recorded in the articulator after an extended
period of time following dental reconstruction on
the other. The accuracy of accumulating these
small deviations and their biological significance for
a living system might be a subject for debate. These
mechanistic declarations of the importance of a
postulated precision in hundredths of millimeters
arouses little appreciation and the shaking of heads
from orthopedists. The pseudo-scientific exaggera-
tion and concomitant denunciation of the retral
border position as a possible variation of maximal
intercuspation should be regarded as an overreac-
tion to the dogma of the gnathological concept.
The reactive dogma of opponents of the retral posi-
tion is just as unscientific and emotional as that of
its dogmatic proponents. Thus, the discussion
191
Structures - Occlusion - Articulation
Kulmer, S.: Long-Term Stability and Occlusion. In: Hösl, E.
und Baldauf, A.: Retention and Long Term Stability, 47–62.
8th International Conference for Orthodontists, Munich
1991. Hüthig Verlag, Heidelberg 1993
Celenza, F. V.: The Centric Position: Replacement and Character.
J. Prosthet. Dent. 30 (4): 591–598, Oct. 1973
The temporo-mandibular joint has the life-
long ability to adapt to changing occlusal
requirements. 
Modifications take place throughout life in all
structures. Thus, from a biological viewpoint,
a healthy system is stable within the joint.
Based on long-term investigations of conva-
lescent patients, Kulmer established that the
position of the temporo-mandibular joints
maintains an exceptionally stable relation to
occlusion and articulation, although the posi-
tion of teeth and the dental arches change
distinctly over a prolonged period of time.
These mechanistic declarations of the impor-
tance of a postulated precision in hundredths
of millimeters arouses little appreciation and
the shaking of heads from orthopedists.
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R. Slavicek • The Masticatory Organ
should concern, above all, the quantity of differ-
ences for the temporomandibular joints and the
dentist's opportunities in this context.
A clear distinction must be made between the
actual physiological and biological situation after
growth and a selected situation based on therapeu-
tic grounds. The value of the retral border position
should be placed in the foreground in diagnostics.
For this reason, I have for many years termed this
position the reference position (RP), in contrast to
the controversial term, "centric relation". I consider
it necessary to achieve a functioning, diagnostically
reproducible point of reference, under biological
conditions. This position also serves as the basis for
well intended, yet invasive, prosthetic intervention.
So-called concepts of occlusion
So-called concepts of occlusion must be mentioned
here and will be discussed in detail later. Occlusal
concepts are artificial organizing principles, which
allow the dentist to apply therapeutic principles
meaningfully. They function, first of all, in a diag-
nostic classification scheme, and then mainly in
occlusal therapy. Nature does not follow such con-
cepts, but forms its rules according to function and
is only interested in allowing function to proceed in
an optimal fashion.
A significant aspect of occlusal concepts is to provide
suitable prosthetics and to optimize the defenses for
the masticatory organ system in regard to para-
function. It makes sense, with regard to occlusal
concepts, to establish "functional areas" within the
dentition, which can be derived from root mor-
phology and the architecture of the dento-alveolar
complex.
The functional areas of occlusion
Let us depart for a moment from the speculative
dogma of occlusal concepts, and look at the mor-
phological concepts of nature in the design of den-
tal inter-relationships. From the viewpoint of root
morphology and the architecture of the dento-alve-
olar region, clearly demarcated functional areas
exist.
192
Ill. 211: The area of the anterior dental arch is limited to the
four anterior teeth.
Occlusion concepts are artificial organizing
principles, which allow the dentist to apply
therapeutic principles meaningfully. 
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The functional area of the 
frontal dental arch
The position of the mandibular anterior teeth rela-
tive to the maxillary teeth, the eruption of the
mandibular front teeth in accordance with the
occlusal axis, and the actual positive labial overbite
of the maxillary incisor in normal dentition create,
upon contact, a twist to and a shift of the upper
front teeth (ill. 211, p. 192, ill. 212 and 213, right).
The absorption of force generally occurs in a punc-
tual fashion in the lingual concavity, and directly
forces the upper tooth outward. As a rule, the shift
does not occur with the mandibular front teeth,
because pressure is diverted to the longitudinal axis
and distributed to the mandibular arch through the
contact points. The guidance always affects indi-
vidual areas of the maxillary anterior region. Thus,
the maxillary front teeth become the proprioceptive
main signal-giver of occlusal contact.
The maxillary central incisor has a shovel-shaped
crown, which recedes into a considerably slimmer
root. Its lingualsurface is distinguished individual-
ly by marginal crests. Here, there also seem to be
typical differences in ethnic groups of the human
race. The incisor’s shovel is spread wide and is met
para-axially in contact and guided outwards, both
tipping and rotating (comp. Reiber),(ill. 214-216,
p. 194). If we follow the cross-section of the crown
from the horizontal view towards the root, the pas-
sage to the root of the maxillary central incisor is at
first rectangular, then becomes rather triangular or
rounded (ill. 217-218, p. 194).
The root cross-section in the area near the crown
has its triangular base directed labially and allows
only minimal rotation in the periodontium. In con-
trast, the dentinal core of the tooth and root
becomes deformed. Through differences in pressure
in the odontoblasts, the deformation acts as an
extremely active and highly sensitive signaler. Teeth
are modified sensory organs - an almost prophetical
observation made by Sigmund in the early nine-
teenth century, which has been confirmed by most
recent research. J. H. Levy (ill. 218, p. 194) pro-
poses the following hypotheses in his work
"Ultrastructural Deformations and Proprioceptive
Function in Human Teeth": "It is proposed that teeth
be considered specialized tactile muccolo-skeletal
organs" and "Application of these hypotheses are exten-
sive, they include both -prevention and treatment ele-
193
Structures - Occlusion - Articulation
Ill. 213: Changing positions of the points of contact shift the
center of rotation (comp. Lugner).
Reiber, Th.: Form und Funktion der Frontzähne – klinische und
experimentelle Untersuchungen. Habilitation, Mainz 1990
Teeth are modified sensory organs.
(Sigmund 1867)
Ill. 212: In contact, the front teeth are shifted para-axially
and deformed ultra-structurally
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R. Slavicek • The Masticatory Organ
194
Ill. 218: The unique structure of teeth make them a highly sensitive sensory receptor and transmitter.
Ill. 214: The lingual surface of the central incisors passes into
a flat and inclined section.
Ill. 215: Contact with the incisal edge causes a highly sensi-
tive sensory input.
Ill. 216: The longitudinal axis of the central incisor frequent-
ly forms a negative angle with the inclined portion. This is a
noteworthy clinical finding relative to the overall approach
from an orthodontic viewpoint.
Ill. 217: Jay Harris Levy, DDS, BSME.
Ultrastructural
Deformations and
Proprioceptive Function 
in Human Teeth
Jay Harris Levy, DDS, 
BSME
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ments and they support the clinical analysis and pro-
per equilibration of occlusion".
Onthogenetically, during the second functional
period of changing dentition, the second maxillary
incisor is involved, for a long time, in laterotrusion
function; its root inclination is normally less steep
than that of the central incisor, which definitely
plays the dominant role for the system in proprio-
ceptive signaling. The lateral incisor has a highly
variable position in terms of both its verticality
position in the frontal arch and from the viewpoint
of rotation. This is primarily because of the la-
terotrusive control function already mentioned,
which plays a significant role ontogenetically, but
also acts as part of anterior group function along
with the canine after maturation.
All front teeth are avoided during mastication, i.e.,
they determine the frontal area end point of the
mastication pattern. This significant behavior dur-
ing mastication will be discussed in detail in the
chapter on Functions and Dysfunctions.
The central incisors and the entire maxillary frontal
arch and its functional harmony with the mandibu-
lar arch are important for speech. Problems related
to the congruence of incisal edges must be adapted
to by compensatory mechanisms (generally the
tongue) in order to achieve comprehensible speech.
The morphology of the frontal arches is therefore
important from the functional point of view; in
addition, they play a determinant role as support
for the facial soft tissue in the labial region and
thereby for the esthetics of the human face.
The incisors arranged on the arch should be regar-
ded as a unit. The inclination of their longitudinal
axes to the lingual functional surface is extremely
variable and individual. The use of the maxillary
incisal longitudinal axis in X-rays and subsequent
diagnostic and the therapeutic applications in
orthodontics based on it, do not appear to be justi-
fied (comp. Slavicek). The lingual functional sur-
face (I avoid the term "guidance surface") does not
fit into a classifiable curvature like the speculative
insertion postulated in the interesting theory of
Nägerl and Kubein-Meesenburg, but rather is a
three-dimensional, irregular surface, distinguished
individually by its marginal crest structures. Most
tactile contacts in function also take place there (ill.
219, left). In other words, the functional palatal
surface of the maxillary anteriors must be dealt
with independent from the angle of the long axis of
the tooth.
195
Structures - Occlusion - Articulation
Levy, J. H.: Ultrastructural Deformations and Proprioceptive
Function in HumanTeeth
Sigmund: Die Empfindung der Zähne. Dtsch. Vierteljahrschr.
f. Zahnheilkunde, H. III, 1867
"It is proposed that teeth be considered spe-
cialized tactile musculo-skeletal organs" (Levy
1994)
The second maxillary incisor is involved, for a
long time, in laterotrusion function.
The central incisors and the entire maxillary
frontal arch and its functional harmony with
the mandibular arch are important for
speech. 
The use of the maxillary incisal longitudinal
axis in X-rays and subsequent diagnostic and
the therapeutic applications in orthodontics
based on it, do not appear to be justified.
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The mandibular anterior teeth, because of their
individual inclination, are a main part of the ante-
rior, dento-alveolar compensation, but still clearly
tend to follow Page's rule. The shape of the root is
longitudinally oval to kidneyshaped, and arranged
radial to the arch. Pressure absorption in closing is
transferred to the longitudinal axis and distributed
over the contact points.
The front teeth are not ostensibly involved in the
parafunctional actions of mature dentition in a den-
tulous person. In general, eccentric bruxism does
not primarily take place over the front teeth, but
rather over the canines. In contrast to the anterior
teeth, the powerful maxillary canines, reintegrated
into the human dental arch, are a part of the emo-
tional management principle of parafunction. They
belong to the frontal arch, complement and con-
clude the tasks of the anterior teeth in the areas of
laterotrusive and protrusive guidance. They stand
slightly prominent in the maxillary arch, with
somewhat vertical roots. Their lingual functional
surface is tangential to the arch and is generally
separated into an implied mesial and distal cavity.
In class I, the mandibular canines stand on the
mesial marginal crest of the maxillary canines or
slightly before it, between the distal marginal crest
of the maxillary laterals and the mesial edge of the
maxillary canines. Because of this arrangement and
character, it is appropriate to describe the anterior
region of the arches as a control and guidance area.
This is accepted in most occlusion concepts, and
dogmatically postulated in the gnathological con-
cept. It is unanimously agreed that the front teeth
are not primarily stressed in the closed jaw position.
The mandibular first premolar is a main part of the
anterior region. In a normal dentition, its buccal
cusp is in close contact with the distal fossa of the
maxillary canine, with which it makes contact in
protrusive function.
196
R. Slavicek • The Masticatory Organ
In class I, the mandibular canines stand on
the mesial marginal crest of the maxillary
canines or slightly before it
Kubein-Meesenburg, D., Nägerl, H., Fanghänel, J., Thieme,
K., Klamt, B., Swestka-Polly, R.: Die allgemeinen Ebenen.
Mandibularbewegungen alsled to the dangerous iatrogenic
diagnostic procedures of our times.
The human being experiences his organism as a
biological puzzle. He discovers "deviations" from
so-called "norms" and considers these, and therefore
himself, to be abnormal. As a logical result thereof,
the individual, in his "self-consciousness", considers
himself to be ill. What modern medicine frequent-
ly lacks, at the end of this seemingly complete
chain of diagnostic efforts, is the synopsis, which is
the conclusion and the guiding hand of a responsi-
ble person. This constitutes the most important
factor, i.e. the care and resulting human relation-
ship between the physician and the patient.
Paradoxically, a part of this lack of communication
in medicine has shifted to dental practice, causing
the contemporary dentist to be confronted with
new responsibilities. The dentist becomes the
patient's confidante and recipient of information
concerning problems, many of which apply only
indirectly to the masticatory organ itself. The latter
has become a platform for more complex medical
problems. This often alienates the purists and
mechanists of our profession, who would like to see
strict limitations being imposed on the authority of
the practicing professional.
14
Formulating a diagnosis is not the task of
some apparatus or, even more dangerous,
some seemingly logical computer program,
but a deeply human decision, replete with
responsibility.
What modern medicine frequently lacks, at
the end of this seemingly complete chain of
diagnostic efforts, is the synopsis.
... apply only indirectly to the masticatory
organ itself. The latter has become a plat-
form for more complex medical problems. 
R. Slavicek • The Masticatory Organ
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At this point it would be appropriate to cite an inci-
dent from a recent conference of the EACD
(European Academy of Cranio-Mandibular Disorders).
The chairman of the "round-table" asked a lecturer,
who had advocated a personal discussion with the
patient before starting therapy, the astounding
question as to whether the dentist was authorized
to carry out such a discussion, as he/she surely
lacked the qualification to do so! Such implied
muzzling should cause modern dentists to recon-
sider their ranking in the medical field by their own
senior experts and by other medical professions.
While doing so, dentists should keep in mind the
fact that, from a functional point of view, they are
taking active responsibility for the "most human"
and most complex of all organs.
It is time for a change in medicine and this is espe-
cially true for dental medicine. Dentistry is one of
the most invasive fields in the medical profession.
Without an intensely medical approach, it is
impossible to appreciate and understand this com-
plex system. It is hoped and, in fact, demanded that
dentists be made aware of their responsibility with
regard to the masticatory organ.
This book is written very subjectively. It reflects my
ideas and opinions about the profession, without a
tendency or intention to list so-called objective
points of view, in consecutive order, as has been
done in the past in carefully prepared literary jour-
nals governed by a certain reserve and scientific
lack of emotion. This contemporary method of sci-
entific "contemplation of one's navel" concurs nei-
ther with my emotionality nor with my self-regard.
I reflect here the high values of those who have
taught me, including all of those whose historical
works I have read and whose ideas have earned my
respect. I reflect here also the spirit of my friends
and colleagues and, above all, my students, who
were able to impart to me a fund of most valuable
ideas during open discussions.
This book is dedicated to my wife, Luise, and to my
children, who have accompanied me along the road
of dentistry, or perhaps more accurately, dental
medicine.
Introduction
15
Capra, F.: Die Wendezeit – Bausteine für ein neues
Weltbild. Scherz Verlag, Bern, München 1983
Without an intensely medical approach, it is
impossible to appreciate and understand this
complex organ. 
This book is written very subjectively. 
I reflect here the high values of those who
have taught me.
I reflect here also the spirit of my friends
and colleagues and, above all, my students.
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Chapter 1
Evolution
The controversial discussion of mankind's
genesis has been in full swing since
Darwin's provocative "Origin of the
Species", often overshadowed by dogmatic
antiquation, and full of a fascinating variety
of hypothetical trains of thought. The pre-
sent book is governed by a strong belief in
the central importance of the stomatogna-
thic system. "Man created himself through
his descriptive speech", said Popper, indi-
cating the central importance of the "organ
of speech" - which we falsely term the
masticatory organ - for the development
of the brain, in our own emergence as a
species. The stomatognathic system of the
new race is a highly refined cybernetic
system of great significance for the orga-
nism. Knowledge of the evolution of the
so-called masticatory organ is absolutely
essential in order to understand its com-
plex functions and developments of the
brain associated with them.
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R. Slavicek • The Masticatory Organ
18
In my many years of clinical activity concerning
the functions and functional disorders of the
masticatory organ along with the scientific pro-
cessing of results and experience, I have been con-
stantly confronted with questions that can only be
answered from the viewpoint of anthropogenesis.
In the course of several years, I have arrived at a
practical mosaic, a framework, for understanding
the significance of the masticatory organ in the
history of our race. I would like to present my
subjective point of view regarding the phylogeny
of the masticatory organ and its functions. I first
coordinated these ideas while preparing a lecture
on the subject of "Creation" for the Arge
Prosthetic Gnathology conference in Gastein in
1994. The subsequent work-up of these ideas and
the resulting conclusions opened new doors with
regard to my comprehension of the masticatory
organ. At this point I would like to cite
Theodosius Dobzansky, whose words are especial-
ly apt for the masticatory organ. ("Nothing in
biology makes sense, unless one regards it in the
light of evolution." Th. Dobzhansky)
This chapter uses an evolutionary, phylogenic and
ontogenetic viewpoint to examine an organ that
was originally concerned with obtaining,
ingesting and processing food into a bolus, and its
transformation into a multi-functional organ,
whose continued designation as the "masticatory
organ" is not only misleading, but also false from
Evolution of mankind
and the masticatory
organ
Dobzhansky, Th., Ayala, F. J., Stebbins, G. L., 
Valentine, J. W.: Evolution. San Francisco 1977
"Nothing in biology makes sense, unless one
regards it in the light of evolution." 
Th. Dobzhansky
Evolution
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the viewpoint of the functional hierarchy of
human organs. It is for this reason that I will
attempt to define and illustrate the various func-
tions of this organ, unique to and reserved for, the
human species. A presentation of the current fun-
ctions of the human "masticatory organ" and their
rapid emergence will show that, in this period of
mankind's evolution, the organ's development
was by no means a slow, gradual or continuous
one in the Darwinian sense (Phyletic Gradualism).
The concept of the "emergence" of new functions
is absolutely correct when applied to the mastica-
tory organ because we are, in fact, referring to
functionally unique and unprecedented creations.
Emergence means the "sudden appearance" of
something principally new and unprecedented.
From the point of view of emergence philosophy,
new qualities emerge in higher "levels of being",
in contrast to those that preceded them. It is
impossible to access former qualities. The entirely
new features of mankind are intimately connected
to theKoppelbewegungen in neuro-muskulär
gesteuerten Getriebesystemen. Dtsch. Stomatol. Berlin 41:
332–336, 1991
Slavicek, R.: Die funktionellen Determinanten des Kauorgans.
Habilitationsschrift, Wien 1982
Ill. 219: The shovel of the central incisor and its dual
arrangement.
The front teeth are not ostensibly involved in
the parafunctional actions of mature denti-
tion in a dentulous person. 
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The frontal lateral dentition area
Functional areas of the premolars
The premolars form the important passage to the
actual support zone of the molars. If we attempt to
analyze the arches according to functional areas,
several possibilities must to be considered.
The simplest classification would involve assigning
the supportive quality to all teeth which can actu-
ally intercuspate with the tooth in the opposite jaw,
and assigning the responsibility of sensory control
to all the other teeth, which only make contact but
have no capability of intercuspation because of their
morphology. In this way, the maxillary arch could
be subdivided into two sections, the anterior canine
group, which would be the "controlling" area of the
arch, and the actual supporting zone, consisting of
the two lateral posterior sections which have a sup-
portive function. This is the same in the mandibu-
lar arch in the anterior area; the exception is the
mandibular first premolar, which generally has no
suitable opposing antagonist with a flat plane mor-
phology for intercuspation as a stop, and therefore
would probably be functionally classified with the
anterior control group. This very simple observa-
tion, from a functional viewpoint, can be stated
simply, and would be appropriate for any "gnatho-
logical" concept.
Thus, a somewhat different, modified classification
of the functional differentiation between the pre-
molars and molars becomes possible. The molars
assume support as their single, main function,
while the premolars assume a supportive function
and also act as laterotrusive control structures (ill.
220-223, p. 198).
As mentioned previously, in ontogenesis, the premo-
lars execute this dual role for a relatively long period
of time. However, even later, in a rather large num-
ber of natural growth occlusions, the principle of
participation of "intercusping" teeth in laterotrusive
control is present. Naturally, mediotrusive contacts
also occur in many dentitions, which may have a
controlling function in mastication. For several con-
ceptual reasons, mediotrusive contacts in the para-
function of most occlusal concepts are undesirable.
A common aspect of the distribution of responsibil-
ities is that the area of pure support is limited to the
molar region. In ontogenesis, only the first molar
has laterotrusive and retrusive eccentric control.
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Structures - Occlusion - Articulation
The premolars assume a supportive function
and also act as laterotrusive control structures.
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R. Slavicek • The Masticatory Organ
198
Ill. 221: The first premolar in the mandible is functionally and
morphologically assigned to the anterior arch.
Ill. 220: The tri-colored scheme highlights the dual role of
the premolars, assuming both a supportive function as well
as the function of control for dynamic mandibular move-
ments.
Ill. 223: The section from a sagittal view in an X-ray projection.Ill. 222: A comparison of the arches from the functional view.
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This eccentric participation in laterotrusive gui-
dance of the first molar can also function in mature
dentition under physiological conditions.
When comparing the various functional areas of
individual groups of teeth, a mutually protective
function can be derived. "Mutually protective occlu-
sion" was and is the objective of the gnathological
concept. The mutually protective function implies
that, in tooth-guided gliding movements, the ante-
rior gliding guidance of the anterior canine group
uncouples the molars and premolars. The guidance
function lies, therefore, by definition, in the anteri-
or canine region and in the joints. For everyday
communicative speech, especially to avoid dogma-
tism, the term "canine control" is more meaningful
than "canine guidance". The term "canine gui-
dance" creates the impression that all of the func-
tional processes on the canine are gliding. This is
not the case at all. Also in parafunction, in eccen-
tric bruxism, it is by no means true that the eccen-
tric movements over the canine, that take place in
the articulator, occur in vivo in the same fashion
(comp. Tamaki, Celar).
In contrast, when you have a forced bite, the joint
and the anterior teeth are perceptibly relieved, or
changed, from their articulations without force. The
premolars can participate in guidance within a less
dogmatic application of the principle, consequently
removing much of the controversy in the argument
between the dogmatists of "canine guidance" and
those of the "group function" schools of thought.
The morphology of the premolars
The morphology of the premolars of the maxilla
and mandible require a special discussion. The
mandibular first premolar generally shows a sturdy
buccal cusp and a rather rudimentary lingual cusp.
Its appearance, i.e., morphology, is therefore some-
what canine-like. Its buccal shoulder is powerfully
arched and prominent; it contributes in great mea-
sure to relieving the maxillary anterior arch in a
protrusive movement.
The occlusal surface has a distinct distal groove. The
mesial groove is rather flat and connected with the
marginal crest.
The mandibular second premolar has a strong buc-
cal cusp and one or two well-formed lingual cusps.
It is a true "premolar". Its distal groove is also more
distinct than the mesial one. The tooth is, as a rule,
single-rooted. The morphological emphasis of the
distal fossa indicates a principle of intercuspation,
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Structures - Occlusion - Articulation
Tamaki, K., Celar, A., Beyrer, S., Aoki, H.: Reproduction of
Intraoral Excursive Tooth Contact in an Articulator with
Computerized Axiography Data. J. Prosthet. Dent. 78, 1997
This eccentric participation in laterotrusive
guidance of the first molar can also function
in mature dentition under physiological con-
ditions.
"Mutually protective occlusion" 
The term "canine guidance" creates the
impression that all of the functional processes
on the canine are gliding. 
The mandibular first premolar generally
shows a sturdy buccal cusp and a rather rudi-
mentary lingual cusp. 
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which would be in keeping with the interdigitation
of the palatal cusps of the other tooth of the same
name. This means that, between the palatal cusps
of the maxilla and the mandibular teeth, even in a
normal dentition, there is no alternating 1:2, but a
1:1 relationship.
The maxillary first premolar presents with two
nearly equal-sized cusps, one buccal and the other
palatal. The palatal cusp is somewhat more massive
and shaped like a mashing cusp. The normally
existing two roots of the tooth are radial to the den-
tal arch, the horizontal cross-section of the root is
kidney-shaped, with a mesial concavity, before it is
divided. Even in the presence of one root, the mor-
phology of the cross-section is kidney-shaped. The
maxillary second premolar is similar to the first one
and supplied with two cusps, although they are
somewhat shorter. It is often single-rooted; the root
cross-section is also frequently kidney-shaped, or at
least suggestive thereof.
The anterior lateral dentition, characterized by the
premolars, continues the anterior arch and is cer-
tainly capable of assuming part-control in eccentric
movement even in mature dentition. We must not
forget that the maxillary premolars exercise this
function for several years during growth. They
form a passage of the frontal arcades to the purely
supportive area (ill. 224-229, p. 201).
The anterior lateral dentition, characterized by the
premolars, continues the anterior arch and is cer-
tainly capable of assuming partial control in eccen-
tric movementseven in a mature dentition. We
must not forget that the maxillary premolars exer-
cise this function for several years during growth.
They form a passage of the frontal arcades to the
purely supportive area (ill. 224-229, p. 201).
The first, second and possibly third molars form the
rather linearly directed so-called support zone.
They are, under normal conditions, very well suit-
ed for sustaining extreme forces for a short period
of time. The forces should be as close to axial as
possible, because the alveoli with their intra-alveo-
lar septi, guarantee optimal absorption of force.
The mandibular first molar possesses five cusps:
two buccal, two lingual and the fifth (distal) cusp is
the smallest and oriented purely to the distal. The
disto-buccal cusp is massively formed and is also
known as the central cusp of the tooth. The two
lingual cusps are long and clearly formed.
However, due to the curve of Wilson and the
200
R. Slavicek • The Masticatory Organ
This means that, between the palatal cusps of
the maxilla and the mandibular teeth, even in
a normal dentition, there is no alternating
1:2, but a 1:1 relationship.
The anterior lateral dentition, characterized
by the premolars, continues the anterior arch
and is certainly capable of assuming partial
control in eccentric movement even in mature
dentition. 
The forces should be as close to axial as 
possible, because the alveoli with their intra-
alveolar septi, guarantee optimal absorption
of force.
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Structures - Occlusion - Articulation
Ill. 224, 225: The maxillary anterior canine arch encompasses the mandibular canine and 1st premolar arch, by means of
overbite and overjet, with a posteriorly directed concavity.
Ill. 226, 227: The transversal-radial arrangement of the premolars causes a series of anteriorly directed concave arches.
Ill. 228: Such a concavity can also be postulated for the max-
illary first molar.
Ill. 229: Interestingly, there is a similar or identical concavity
existing at the longitudinal axes of the condyles.
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absence of antagonistic morphology, their tips do
not act as stops. The occlusal surface has a fragile,
mesial groove (anterior fovea) and a more distinct
distal, "central" groove. This tooth has two roots,
which are directed mesial to distal. The mesial root,
is especially wide and shovel-shaped, plus it is gen-
erally curved distally.
The mandibular second molar is similar to the first
molar, however without the fifth cusp. The root
relationships resemble those of the first molars. The
mandibular third molar has a variable morphology
in both the crown and the roots.
The maxillary first molar is a four-cusped tooth,
with two buccal and two lingual cusps. The mesio-
lingual (mesio-palatal) cusp is formed massively
and generally the largest cusp in the dentition. It is
also known as the central cusp of the maxillary first
molar. The tooth usually has three roots, the most
powerful of which lies palatinally and inclines
medially in the direction of the roof of the palate.
The two buccal roots lie mesial and distal and follow
the zygomatico-alveolar crest in their inclination.
The maxillary second molar has a highly variable
morphology and is often only tri-cusped. It then
has two buccal and only one, very wide, palatal
cusp. In many cases only one root is present, and its
form is variable. The maxillary third molar is simi-
lar to the mandibular one in that it is exceptionally
variable in terms of both, crown form and root
morphology.
The occlusal planes
Definitions
The plural form of the title of this section was cho-
sen intentionally, as there are many definitions of
the so-called occlusal plane and they need to be
explained and applied from a functional viewpoint.
The position of a defined occlusal plane in space is
of great functional and dynamic significance in
diagnostics. The individual position of the jaws
(bases) relative to each other changes permanently
in ontogenetic development and are compensated
for during growth, by the development of the
dento-alveolar process, with the goal of organism
to achieve the best possible functional relationship.
Consequently, it is meaningful in a discussion
202
R. Slavicek • The Masticatory Organ
The tooth usually has three roots, the most
powerful of which lies palatinally and inclines
medially in the direction of the roof of the
palate.
The plural form of the title of this section
was chosen intentionally.
The position of a defined occlusal plane in
space is of great functional and dynamic sig-
nificance in diagnostics.
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203
Structures - Occlusion - Articulation
aimed at setting of standards, to establish an exact
concept for the occlusal plane (OP).
The prosthetically defined occlusal plane is based
on the mandible and approximates a triangle from
the inferior incision (mandibular incisal edge) to the
two distal cusps of the mandibular first molars. We
refer to this definition of the prosthetic (gnatholo-
gical) occlusal plane when we use the articulator
and mount casts, in X-rays analyse, or when we
relate the condylar (hinge axis) track to an articulator
or make an analysis after doing some type of condy-
lar movement recording.
Nevertheless, it should be noted that during a dia-
logue on this subject, it may be advantageous to
refer to variously defined occlusal planes: the max-
illary occlusal plane (comp. Sato) is defined by the
superior incision (maxillary central's incisal edge)
and the distal contact point of the maxillary first
molar. A posterior and anterior occlusal plane (comp.
Sato-Slavicek) can be defined for the maxilla and
mandible, applicable to the sections in front of, or
behind, the contact points of the premolars to the
molars. Ricketts defines the occlusal plane from the
mandibular first molar to the intersection of the
two overlapping canine tips on an X-ray. He halves
the cusptip-to-cusptip distance created by this
overlap. The results of all these interpretations con-
jure up a wide array of biological standard deviations,
leading to absurd uniform therapeutic concepts.
The illustrations show the relatively wide range of
defined prosthetic OP statistically and compare
them with various other reference planes (ill. 230-
241, pages 204-205).
When regarding the occlusal plane, it should
always be remembered that it is a simplified repre-
sentation of a functionally determined dynamic
principle. It must be borne in mind that the
occlusal relationship between the maxilla and
mandible is a functional one, and the occlusal plane
depicts a dynamic principle of the joint track. The
third dynamic element to be discussed is anterior
guidance from the maxillary arch.
The functional determinants of the masticatory
organ system can be didactically considered in a
simplified way from the sagittal view. The dyna-
mic conceptual scheme can be optimally displayed
on an X-ray and applied didactically or diagnosti-
cally (ill. 242-247, p. 206).
Sato, S.: Alteration of Occlusal Plane Due to Posterior 
Discrepancy Related to Development of Malocclusion – 
Introduction to Denture Frame Analysis. Bulletin of Kanagawa
Dental College 15 (2): 115–123, 1987
Ricketts, M. R.: Cephalometric Synthesis. Americ. J. of Orthod.
46, 1960
When regarding the occlusal plane, it should
always be remembered that it is a simplified
representation of a functionally determined
dynamic principle. 
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204
R. Slavicek • The Masticatory Organ
Ill. 230, 231: The prosthetic occlusal plane through the hinge axis and orbital point. The dark blue line corresponds to
the actual location in this example.
Ill. 232, 233: The prosthetic occlusal plane to Frankfurter horizontal.
Ill. 234, 235: The prosthetic occlusal plane to the palatal plane.
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Structures - Occlusion - Articulation
Ill. 236, 237: The prosthetic occlusal plane to Camper's plane.
Ill. 238, 239: The prosthetic occlusal plane to the facial plane.
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206
R. Slavicek • The Masticatory Organ
Ill. 242, 243: The prosthetic occlusal plane to the lip cleft.
Ill. 244: The lateral face as a dynamic system on the lat-
eral X-ray.
Ill. 245: The hinge axis - orbital plane and the tangent to
the lingual concavity of the central incisors.
Ill. 246: The sagittal condylar track simplified as a cord
to the fifth millimeter of the protrusive track.
Ill. 247: The occlusal plane in a simplified system show-
ing the dynamic determining factors.
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Spheres of occlusion
Nothing in the occlusion of human adults is two-
dimensional. This lapidary statement is made at the
very beginning of the discussion concerning the
sphericity of the human masticatory organ. Based
on individual development of the ascending branch
of the mandible, the occlusal tables of the lateral
tooth region are increasingly inclined towards the
joint. The more the ascending branch develops
superiorly, the more the joint condyle and its hinge
axis distance themselves from the hypothetical
occlusal plane, and the smaller is the radius of cur-
vature in the lateral tooth region. The arrangement
of the dentition and the formation of their roots in
ontogenetic development are influenced by the
point in time of their eruption and the distance to
the mandibular joint. The more distally the tooth
lies and the greater the distance to the mandibular
joint, the stronger is the tendency of the occlusal
table to incline towards the joint. Consequently, a
sagittal view represents a superiorly directed, con-
cave alignment of the mandibular dentition. This
typical behavior was recognized and described by
Spee, and is therefore termed the Curve of Spee (ill.
248, 249, right). The mathematical determinants
of this curve were made legitimate by Orthlieb. He
postulated the so-called DPO, the "distance to
plane of occlusion". The greater the DPO, the
smaller the radius of the Curve of Spee. A review of
comparative research will demonstrate this.
The behavior of the occlusal plane
and spheres in comparative research
For the alligator and most other reptiles, a Curve of
Spee does not exist; they have a DPO of zero. In
other words, here we have a plane that serves as an
occlusal relationship. Among mammals, compari-
son of the carnivore and herbivore principles shows
that the distance of the occlusal plane to the temporo-
mandibular joint determines the dimensions of the
spherical components (ill. 250-253, p. 208). We
will deal with the significance of spatial differences
for mastication at a later point in time.
Naturally, the spherical principle of human denti-
tion cannot be described from the sagittal view
alone. Transversal compensatory differences in the
207
Structures - Occlusion - Articulation
Ill. 248: Diagram of the sagittal compensation curve.
Ill. 249: Compensation curve on an adopted model.
For the alligator and most other reptiles, a
Curve of Spee does not exist, they have a
DPO of zero.
Graf Spee, F.: Die Verschiebungsbahn des Unterkiefers am
Schädel. Arch. Anat. Physiol. 16, S. 285–294, 1890
Orthlieb, J. D.: The Curve of Spee: Understanding the Sagittal
Organization of Mandibular Teeth. Marseille 
Orthlieb, J. D., Slavicek, R.: Geometrische Interpretation 
der Spee-Kurve. Zschr. f. Stomatol. 82, S. 1–18, 1985
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208
R. Slavicek • The Masticatory Organ
Ill. 250: The principle of an actual plane, using the alligator as an example.
Ill. 251: The dentition of an alligator was conceived as a snapping trap and does not serve
to break up food other than to sometimes tear off chunks from the remaining carcass.
Ill. 252: Canine-type predator. The temporomandibular
joint is near the occlusal plane.
Ill. 253: Herbivores have a large distance to the occlusal
plane and an accentuated compensation curve in occlu-
sion, which, if extended, goes through the condyle.
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inclination of the occlusal table are also found in the
lateral tooth region. If we lay frontal sections in
succession from anterior to posterior through the
dentitions of the maxilla and mandible, we recog-
nize the differences in the inclination of the occlusal
table within the individual frontal sections. These
transversal flexion radii are termed Wilson's curves.
They do not represent the round sphere shape of an
individual's calotte-skull cap, but rather a sequence
of different radii.
Summary of the occlusal planes
Defined occlusal planes serve, first of all, to simpli-
fy the representation of skeletal and occlusal rela-
tionships. The occlusal planes may be defined arbi-
trarily. However, they should be explained and
their predictive value evidenced by statistical find-
ings on occlusions that have grown and developed
naturally, with normal function.
The three-dimensional sphere is described by com-
pensating curves. The sagittal compensating curve
is designated the Curve of Spee, the transversal
curves are known as Wilson's curves. The Curve of
Spee describes the progress of the buccal cusps of
the mandibular lateral segments from the canine to
the last molar (the front teeth are not included).
Wilson's curves are not at all uniform, but rather
only apply to the left and right same pair of teeth
in coronal section. They can, but need not, be equal
for the maxilla and the mandible. The compensa-
tion curves depend on the distance of the hinge axis
of the mandible to the mandibular occlusal plane.
The individuality of compensation is partly deter-
mined by the spatial position of the occlusal plane
per definition to the mandibular joint (DPO).
Thus, sagittal and transversal spheres follow indi-
vidual skeletal rules. The compensation curves
allow for a uniform, dynamic distance of the denti-
tions during function. The attempt to describe
them three-dimensionally by a calotte (comp.
Monson) has been opposed.
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Structures - Occlusion - Articulation
Monson, G. S.: Applied Mechanics to the Theory of Mandibular
Movements. Dent. Cosmos, 74: 1039–1053, 1932
The three-dimensional sphere is described by
compensating curves. 
Wilson's Curves are not at all uniform.
Thus, sagittal and transversal spheres follow
individual skeletal rules. 
The attempt to describe them three-dimen-
sionally by a calotte (comp. Monson) has
been opposed.
Ill. 254: The white cross-bars show different radii from ante-
rior to posterior. 
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210
R. Slavicek • The Masticatory Organ
Functional lines of occlusion
To facilitate didactic understanding of occluso-
articular function, we will consider the dental arch-
es from the viewpoint of their overall function and
postulate the so-called "functional lines" within the
arches. These are:
The active centric arch
The passive centric occlusal 
The esthetic-functional occlusal arch
The three interrupted occlusal arches
The active centric arch consists of the incisal edges
of the anterior teeth, the canine tips, and the buc-
cal cusps of the premolars and molars of the
mandible (ill. 255 and 256, left).
The passive centric arch consists of the marginal
crests of the anterior teeth, the canines and premo-
lars, along with the marginal crests and grooves of
the molars of the maxilla (ill. 258 and 259, p. 211). 
The esthetic-functional arch consists of the incisal
edges of the anterior teeth, the canine tips, the buc-
cal cusp tips of the premolars and molars of the
maxilla. It has no antagonistic contact with the
opposite jaw in a normal dentition (ill. 260, p. 211).
The interrupted arch of the maxillary active centric
consists of the lingual cusps of the premolars and
molars (ill. 261, p. 211).
The interrupted arch of the mandibular passive
centric consists of the grooves of the premolars and
molars (ill. 262, p. 211).
The interrupted arch of the lingual non-centric
mandibular cusp has, as does the esthetic functio-
nal maxillary outer arch, no antagonistic contact
during regular intercuspation.
In didactics, but also in the diagnostics, planning
and treatment of occlusion, a graphic representa-
tion of the variousdental arches and their relation
to each other has been proven useful.
In conclusion, I will try to describe normal denti-
tion in order to have some "rules" with which to
compare typical malocclusions.
• The active centric arch
• The passive centric occlusal
• The esthetic-functional 
occlusal arch 
• The three interrupted 
occlusal arches
Ill. 257: Active centric, mandible.
Ill. 255: Arch of the active centric in the mandible.
Ill. 256: Active centric, maxilla.
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211
Structures - Occlusion - Articulation
My heartfelt thanks to Prof. Kulmer in Innsbruck for the
excellent didactic photographs of the illustrations 255-262
(pages 210 and 211).
Ill. 258: Passive centric arch in the maxilla. Ill. 259: Passive centric, maxilla.
Ill. 260: The esthetic-functional arch in the maxilla. Ill. 261: Esthetic functional arch - passive centric arch
and the active centric of the lingual cusp in the maxilla.
Ill. 262: Comparison of the maxillary and mandibular
arches.
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R. Slavicek • The Masticatory Organ
Normal dentition and malocclusions
The characteristics of "ideal" dentition
(Class I)
• The active and passive centric match
• The teeth have a 1:2 relation, the mandibular 
1st premolar and the maxillary last molar have 
only one antagonist
• The esthetic-functional arch stands in a positive
horizontal overjet and overbite and allows satis-
factory functional and controlling free space
• The maxillary active lingual partial arch inter-
cuspates with the distal fossa of the mandibular
premolars and central fossa of the mandibular 
molars in a 1:1 relationship
• The mandibular lingual partial arch protects the
tongue during functional movements
• The anterior teeth show individual inclination 
and relation (compensation)
• The mandibular canine stands in a 1:2 relation-
ship to the maxillary arch
• The mandibular first molar stands in pure 1:2 
intercuspation to the maxillary arch
• The skeletal construction of the mandible and 
the inclination of the dentition to the skull 
determine the spherical construction.
So-called dysgnathias, anomalies of the jaws
In naturally developed dentitions we are certainly
much more frequently confronted with the "small
errors" of moderate deviations from the norm than
with a purely eugnatic regular bite. In spite of these
small deviations, the masticatory organ functions
without disturbances in most cases. Nature gener-
ally achieves this by means of typical compensato-
ry mechanisms. Cases of pronounced abnormal
jaw(s) and dentition relationships are common in
everyday practice. Nevertheless, the functional state
can be good or at least acceptable for a long period
of time. Direct correlation between dysgnathia and
dysfunction is not provable statistically.
Therefore, it is important for the dentist to work
constructively on the basis of a "normal dentition"
concept, in order to learn the rules of dysgnathia
and to adapt any invasive therapy to the rules. The
Dentition with "small errors" is much more
common than a purely eugnathic regular bite.
A direct correlation between dysgnathia and
dysfunction is not provable statistically.
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Structures - Occlusion - Articulation
following will describe the most typical forms of
abnormal tooth and jaw relationships and attempt
to classify them in morphological syndromes. Of
course, this is only an attempt; there are naturally
exceptions to the rules.
The morphological syndrome of Class II/1
• the functional arches are only congruent in small
sections
• joint-related tendency to compensatory protru-
sive position
• frequent functional "double-bite position"
• typical lyre-shaped maxillary arch with anterior
compression
• tendency towards elongation of the mandibular
anterior arch
• dento-alveolar compensation in the mandibular
anterior region
• dento-alveolar decompensation in the maxillary 
anterior arch, protrusive inclination of the max-
illary anterior teeth
• soft tissue phenotypically somewhat "soft"
• ligaments phenotypically somewhat loose
• skeletally somewhat neutral to dolychofacial
• vertical with good compensation somewhat low 
to neutral
• DPO generally less than average
• the articular eminence average or flat (in deep
bite in the anterior region, exceptions are possi-
ble)
• mentally, the "open", "smiling", "cooperative", 
and "emotional" type, who likes to laugh 
and cry
Distocclusion of Class II/1 is frequently a joint-
related protrusive arrangement (anterior position-
ing). This position is supported by means of the bi-
laminar zone in the joint (ill. 263, p. 215) and
actively maintained by muscular programs. This
results in a double-bite position, the so-called
Sunday bite, which may or may not function for the
individual without problems. Vertically, the well-
compensated Class II/1 is generally average or low.
Distocclusion of Class II/1 is frequently a
joint-related protrusive arrangement (anterior
positioning). 
Syndrome
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A functionally well-compensated Class II/1 has
typical features in terms of the position of teeth and
their arrangement.
The mandibular arch has a small and retrally lying
base, with good dento-alveolar compensation, i.e.
strong tooth inclination towards the anterior. The
occlusal plane points towards the joint with a small
DPO. The ascending branch of the mandible is
rather short in comparison to the horizontal one.
The Curve of Spee generally has a large radius.
The mandibular anterior arch is vertically more
strongly erupted, a small step is seen behind the
mandibular canine, the first premolar lies some-
what deeper, the disto-incisal edge of the canine is
somewhat exposed. The alignment of the incisal
edges shows a positive convexity superiorly.
The maxillary arch has a decompensated, i.e., pro-
trusive anterior dento-alveolar region, which leads
into transversal premolar crowding. In the molar
region, the arch increases in width, creating the
lyre-shaped line of the maxillary dentition, into
which the mandibular arch fits well, in a protruded
position.
In an articular well-compensated Class II/1, which
can often function for a lifetime without major
complaints, the teeth can take on a retral position,
resulting from light chin guidance (ill. 264, p. 215)
or active retraction by the individual. The first con-
tact in the retruded contact position (RCP) typical-
ly occurs on the maxillary first premolar.
The disto-incisal edge of the mandibular canine
touches the mesial marginal crest or the mesio-lin-
gual cusp attachment of the maxillary first premo-
lar. This typical early retral contact generally lies at
the end of a protrusive gliding facet, which reveals
activity (ill. 265, p. 215). This gliding facet is the
steepest "retrusive" guidance mechanism in the
dentition, which leads from a protrusive to a retral
joint position (ill. 266, p. 215).
Because of its root architecture, the first premolar is
perfectly suited for assuming proprioceptive control
for this position. Its transverse (generally) double
root is ideally geared for retrusive control (ill. 267,
p. 215). The protrusive, maxillary front tooth is
actively caught up and held by the lower lip (ill.
268, p. 215).
The slightly protrusive position of the mandible is
further actively exaggerated by the subject (gene-
rally women) and thereby subconsciously overcom-
pensated for esthetic reasons. Speech problems
214
R. Slavicek • The Masticatory Organ
The mandibular anterior arch is vertically
more strongly erupted, a small step is seen
behind the mandibular canine.
This typical early retral contact generally lies at
the end of a protrusive gliding facet.
Because of its root architecture, the first pre-
molar is perfectly suited for assuming propri-
oceptive control for this position. 
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215
Structures - Occlusion - Articulation
Ill. 263: The retro-articular vascular padding of the bil-
aminar zone can bring the joint into a compensatory pro-
trusive position, compensating for a skeletal ClassII
position.
Ill. 264: A slight manipulation on the chin creates dis-
tinct retraction of the mandible.
Ill. 266: The intercuspal position lies distinctly protru-
sively on the sagittal condylar track.
Ill. 267: The double root of the first premolar and its
anteriorly directed concavity are excellently suited for
producing proprioceptive signals.
Ill. 268: The two antagonistically arranged control sys-
tems, from anterior and posterior.
Ill. 265: The typical first early contact of an articularly
compensated Class II with simultaneous aplasia of the
maxillary small incisor on the right.
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associated with the phonation of the "S" sound are
generally cleverly compensated for by the tongue.
However, this description of dysgnathia and the
possibilities of compensation also show that such
systems are susceptible to changes, and easily prone
towards decompensation.
The morphological syndrome of Class II/2
Class II/2 typically shows wide apical bases. The
two dento-alveolar processes develop typical, con-
centric internal progressing forms, so that the coro-
nal arch is generally narrower than the apical one.
The retrally inclined maxillary front teeth find no
functional abutment from the lower lip in vertical
development and develop vertically into the lower
vestibule until they are stopped by the generally
powerful and active labial muscles. The mandibu-
lar front teeth also erupt strongly and stand gene-
rally higher than the cleft. The steep, deep anterior
canine group is more of a hindrance to protrusive
function; therefore the functional pattern of Class
II/2 is transversal. The ascending branch develops
in a strong vertical fashion, the temporo-mandibu-
lar joint develops a steeper articular eminence. In
most cases, the jaw bases have no real distal rela-
tion, but rather a neutral relationship. Dento-alve-
olar retraction takes place due to the very powerful
and active circumoral mimic musculature, which
especially affects the mandibular alveolar process.
The powerful muscles prevent dento-alveolar com-
pensation. The maxilla surrounds the mandibular
arch, the buccal overbite is minimal in the lateral
tooth region and there is a great danger of
mediotrusive guidance. The vertical is not always,
but frequently, reduced. With the exception of 
vertical compensation, other compensatory
processes do not take place due to the strong mus-
cular dominance. Because of the steep joint track,
intermittent or permanent joint noise occurs.
216
R. Slavicek • The Masticatory Organ
• Functional arches match to a great extent
• The functional free space is limited
• Near or in RP, relative to the joint
• Wide coronal and apical arch in the 
maxilla
• Tendency to dento-alveolar retrognathia in
the mandible
• Typical mandibular form with high ascend-
ing branch
• Inclination of the maxillary and mandibu-
lar anterior teeth
• Dental deep bite
• Frequently, also skeletal deep bite
• Large DPO, accentuated sphere
• Phenotypically strong ligaments
• Frequently steep articular eminence (with 
possible exceptions)
• Mentally the "cool", "strict", "reserved", 
"serious" type
• Tendency to mentally dominated parafunc-
tion
With the exception of vertical compensation,
other compensatory processes do not take
place due to the strong muscular dominance. 
In most cases, the jaw bases have no real dis-
tal relation, but rather a neutral relationship. 
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217
Structures - Occlusion - Articulation
The morphological syndrome of Class III
Class III is not uniform in its skeletal presentation.
Nevertheless, the phenotype shows characteristic
traits.
Skeletal and dento-alveolar compensation takes
place in the lower face, especially in the anterior
area, and is predominantly vertical. The chin sym-
physis is extended, the mandibular dento-alveolar
complex is long and somewhat narrow, the
mandibular anterior teeth are retro-inclined. The
longitudinal axes lie in the D-point or even in front
of it. The posterior facial height, in contrast, remains
rather short; the gonial angle is very blunt, the chin
angle sharp (these details will be dealt with in a
later section). The arches of the maxilla and
mandible have a typical tendency towards incon-
gruence. The maxillary arch is too short and nar-
row, the mandibular arch too long and wide.
Consequently, the problem of so-called functional
lines matching poorly or not matching at all is a
common one. Frequently, the active centric arch
meets the functional-esthetic arch of the maxilla, or
even lies buccolabial to it. This results in special
problems, which are compensated for in a typical
way in Class III. The function is generally some-
what sagittal, control takes place on the buccal
cusps of the maxilla and on the distal appendage of
the maxillary canine. The vertical front overbite is
minimal. Nevertheless, functionally well-compen-
sated Class III cases are common and create esthe-
tic problems rather than functional ones.
• The functional arches are sagittally and
transversally non-matching.
• Maxilla generally sagittally and transversal-
ly under-developed.
• Mandible both sagittally and transversally
dominant.
• The functional arches do not match.
• Therefore, in serious cases, partial or total
cross bite dentition.
• The occlusal plane has a tendency to poste-
rior-inferior.
• The mandibular anterior symphysis is high
and retro-inclined (dento-alveolar compen-
sation).
• Typical compensation mechanisms:
• Skeletal high vertical
• High anterior symphysis
• Retro-inclination of the mandibular front
• Reduced frontal and lateral overbite
• Sagittal functional pattern
• Near the joint or in RP
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Chapter 3 
Functions
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The functions of the masticatory organ
play a central role for the human orga-
nism. The most important of these cer-
tainly is oral communication, which inter-
connects 6 billion people. This unique,
complex and abstract ability of expression
from the human brain, wrote the success
story of human beings. Speech, as a trans-
mitter, made it necessary to evolve a
receiving system, namely the eyes and
ears, which are intimately connected with
the functions of the masticatory organ.
The maneuverable balance of the head
introduces posture as a further inter-
related function - an overlap, that be-
comes especially important in functional 
disorders, found in the routine of doing 
clinical dentistry.
Self-consciousness, self-perception and
esthetics are central functions of the face,
that directly become related to some of
the psychological aspects of being human.
The psyche and the masticatory organ,
processing of suppressed and repressed
problems, are poorly understood tasks
carried out by the so-called masticatory
organ, which enhances the importance of
the dentist in medicine.
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220
R. Slavicek • The Masticatory Organ
The "eating tools" or "guzzling tools"
First of all, the chewing system serves in the recep-
tion, mastication and ingestion of food. Evolution
developed a large number of fanciful variations of
such "tools". These highly specialized systems func-
tion as tools during the ingestion and, in some
cases, the processing of food. Very few of these sys-
tems found in nature are actually "chewing tools".
However, some systems are highly developed and
thereby suitable for grinding food and preparing it
for further digestion. If we compare a selection of
these systems from reptiles, canine-like predaceous
animals and plant-eating ruminants, the differences
in functional principles become evident.
Reptiles
The bio-mechanical makeup of the alligator shows
absolutely no indication of a spherical arrangement
of the dentition. The jaw joint lies within the plane
of occlusion; there is no flexion at all within the
arranged dentition; it is a chewing plane in the true
senseof the term. The socket of this primitive jaw
joint is mandibular, the stylus of the joint process is
maxillary. The function of the "tool" is to grasp a
prey and to hold it securely. The organ is not sui-
table for grinding food, but rather for holding and
Mastication
Evolution developed a large number of fanci-
ful variations of such "tools".
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221
Function - Mastication
swallowing. This bio-mechanical principle is pre-
dominantly seen in reptiles (ill. 1 and 2, p. 222).
Carnivores
The dentition of a canine-like predaceous animal is
considerably different (ill. 3, p. 223).
One conspicuous detail is the group of three canine
teeth, which articulate in a special way. They close
and wedge, in a kind of force-bite, whereby the
mandible is pressed retrally. The condyle of the jaw
joint is pressed against a strongly formed post-gle-
noidal process as a buttress. Powerful closing mus-
cles permit secure fastening onto and killing of
prey. The canines are anchored very securely in the
jaw and are therefore true killing "weapons". The
rather flat, less powerful front teeth serve to scrape
tissue from a hard surface (bone).
The premolars do not close in occlusion; instead
there is a bi-lateral, open bite in this area. The run-
ning, hunting predaceous animal (e.g., a wolf), cre-
ates the necessary balance of warmth through a
cooling system of the tongue, which hangs out at
the side between the premolars when the animal
"pants" while it runs.
The so-called first molar is by no means a "grinding
tooth", rather it is formed like a powerful chisel that
bites past its antagonist, similar to a scissors. The
tooth cuts through flesh and tendons, and chisels
bones into pieces (ill. 4 and 5, p. 223). In contrast,
the most posterior teeth actually occlude, with
"chewing surfaces", and serve in food preparation
by flattening tough, fibrous structures such as
sinew and tendon. Flesh, however, is gulped in
large chunks (ill. 6 and 7, p. 224).
If we construct an occlusal plane through this ante-
rior group, the imaginary extension would pass
through the condyle of the temporomandibular
joint. The distance of this constructed occlusal
plane to the temporo-mandibular joint would be
zero or very small. (This distance was defined by
Orthlieb as DPO, "distance to plane of occlusion",
and a dependence on the spherical construction of
the masticatory organ system was shown.) (ill. 8, p.
224).
The posterior true molars, in contrast, incline infe-
riorly and superiorly in a sharp bend; an imaginary
plane would lie distinctly anterior to the temporo-
The organ is not suitable for grinding food,
but rather for holding and swallowing. 
The dentition of a canine-like predaceous ani-
mal is considerably different (ill. 3, p. 223).
The condyle of the jaw joint is pressed
against a strongly formed post-glenoidal
process as a buttress. 
The canines are true killing "weapons". 
The so-called first molar is by no means a
"grinding tooth".
Carnivores
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222
R. Slavicek • The Masticatory Organ
Ill. 2: The plane of the dentition follows a straight line to the jaw joint.
Ill. 1: The jaws and dentition of an alligator are formed like a snapping trap and do not grind food.
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223
Function - Mastication
Ill. 4: The chisel-like like form
of the first "molar", which acts
with its antagonist as a scissor.
Ill. 5: The buccal overbite of
the first molar and its rudi-
mentary lingual cusp deter-
mine the lateral border move-
ment pattern in a dog.
Ill. 3: The skull of a canine
carnivore in a typical section:
the group of canines, premo-
lars do not occlude, first
molars are chisels, molars with
a strongly inclined occlusal
plane. Note the strong buttress
of bone in the post-glenoidal
process.
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224
R. Slavicek • The Masticatory Organ
Ill. 6 (above, left): The recording section
of the sirognathograph.
Ill. 7 (above, right): The dog while
chewing and swallowing food.
Ill. 8 (middle, left): The jaw joint lies
within an extended occlusal plane, if we
exclude the last molars.
Ill. 9 (middle, right): Sagittal border
track scheme with a retral force-bite.
Ill. 10 (right): This sagittal view shows
the retral force-bite. The frontal view is
distinguished by the first molars (corre-
sponds to the human scheme, character-
ized by the molar). The superior view is
marked by powerful lateral ligaments.
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225
Function - Mastication
mandibular joints. This bend allows for flat, grind-
ing movements, which would otherwise be hin-
dered by the opposing teeth. The maxillary first
chisel-like "molar", with its lingual slope, shows a
similar intercoronal opening angle to its mandibu-
lar antagonist, as with ideally occluding human
canines. Therefore, a frontal scheme of the border
movements of a dog is very similar to that of a non-
abraded human dentition. In the latter, however,
the limitation is not effected by the molars, rather
it is limited by the canines (comp. May, Zetner) (ill.
9-10, p. 224).
Herbivores
The skull of a ruminant serves as an example of this
species. The construction is fundamentally different
from the carnivorous type; the form of the
mandible displays a fully differentiated proportion-
al arrangement. The ascending branch (ramus) is
considerably higher, the vertical distance of the
dentition (-plane of occulsion) to the temporo-
mandibular joint is large.
The strong radius of the Curve of Spee of the den-
tition going posteriorly and superiorly is especially
pronounced, giving this masticatory organ its
emphatically spherical arrangement. The maxillary
anterior teeth are missing altogether and are
replaced by a flat, horny ridge. The mandibular
anterior teeth are shaped like a shovel and open to
the front, lying antagonistic to the upper ridge.
These flat "tongs" enable the herbivore to grasp and
then tear plant food off its root system.
There is a gaping, wide, open edentulous space
between the anterior and lateral dentition. From a
superior view, the arrangement of the premolars
and molars is not arched, but in a straight line. If
an imaginary occlusal plane was extended posteri-
orly from the mandibular anterior tooth to the first
molar, this plane would lie far inferior to the
mandibular joint (ill. 11, left). From a sagittal view,
the arc of the Curve of Spee passes just before the
temporo-mandibular joint. If we draw a DPO,
there is a markedly longer distance to the joint
trochlea in comparison to the carnivore principle
(ill. 12, left).
Herbivores abrade their dentition early into a "bal-
anced" articulation. This guarantees an optimal
grinding surface to process finely fibred vegetable
Zetner, K., Mai, M.: Electronical Assessment of Chewing
Movements in the Dog. Proceedings of the Third World
Veterinary Dental Congress, Philadelphia 1993
An imaginary plane would lie distinctly ante-
rior to the temporo-mandibular joints. 
Therefore, a frontal scheme of the border
movements of a dog is very similar to that of
non-abraded human dentition. 
The ascending branch (ramus) is consider-
ably higher, the vertical distance of the denti-
tion (-plane of occulsion) to the mandibular
joint is large.
Herbivores
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food. Further optimization is achieved in "rumi-
nants" by a second processing pattern (the rumi-
nant's "pre-digestion") (ill. 13-15, p. 227).
The phylogenetic 
changes from 
Hominoids to Hominids
to Homo sapiens
The Pongids
Pongids are predominantly plant-eaters. Only the
chimpanzee has shown the desire to augment a
plant diet, with the option of eating meat.
The dentition of adult Pongids is not arch-shaped,
in contrast to its deciduous dentition. Its dentition
consists of two nearly parallel lateral rows formed
by premolars and molars. The powerful canine is
segregated from the lateral group, and separated
from the anterior group of teeth by a diastema, the
so-called "primate gap" (ill. 18 and 19, pages 228-
229).
The canine in male Pongids develops and grows
until late into adulthood. The apicalforamen clo-
ses rather late in life. This suggests that, in contrast
to the predator, the canine is not a true killing
weapon, but should be regarded as a sign or sym-
bol of strength.
Pongids abrade their dentition in both right and
left lateral areas early, in order to achieve a balance
between the contralateral and ipsilateral sides for
masticatory functional contacts during articulation.
This is necessary for the survival of the species,
which are primarily herbivorous "leaf-eaters".
226
R. Slavicek • The Masticatory Organ
Ill. 12: The dentate mandible of a deer. The occlusal curve of
the lateral teeth would, if extended, pass close to or through
the temporo-mandibular joint.
Ill. 11: The distance to the occlusal plane is large.
The canine in male Pongids develops and
grows until late into adulthood. 
... should be regarded as a sign or symbol of
strength.
Pongiden
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227
Function - Mastication
Ill. 14: Attaching the perma-
nent magnet to an anterior
portion of the mandibular jaw.
Ill. 15: The transversal masti-
cation pattern of a ruminant
shows a completely flat excur-
sion track.
Ill. 13: The sheep - a typical
ruminant.
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228
R. Slavicek • The Masticatory Organ
Ill. 17: The comparison of a Pongid arch to the human arch shows the drastic difference in the alignments of the dentitions. The
gaping "primate gap" behind the front teeth allows for transversal vectors, for the breaking-up of vegetable food.
Ill. 16: The orangutan is omnivorous, eating predominantly vegetation. Its dentition must be suitable for processing this vegetable
food.
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229
Function - Mastication
Ill. 18, 19: The morphological makeup
of the molars in anthropoids shows
hardly any difference to human molars.
Dentition in adult anthropoids shows an
evident tendency toward Class III den-
tition.
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Homo sapiens
The viscerocranium developed the human mastica-
tory system into a closed-arch construction of the
jaw and dentition, as a result of the vehement
enlargement of the neurocranium, especially trans-
versally (ill. 20-28, pages 231-233).
This organ, which had primarily served in the
ingestion of food in phylogenesis, was redesigned
into a multifunctional organ. Although oral com-
munication was undoubtedly its main function, it
also played a role in maintaining the balance of the
freely held head and in processing psychologically
induced parafunctions. In addition, the human
masticatory organ has to fulfill the facial expression
requirements of non-verbal communication. The
esthetics of the face is characterized by the mastica-
tory organ and its diversity, dynamics and expres-
sion. Esthetics are involved to a great extent in the
"self-awareness" of the individual (comp. Huber).
The neuromuscular system (NMS) moves the
mandible in patterns, which are maintained propri-
oceptively by specific individual tooth contacts or
through independent programs.
The NMS is involved in the following functional
areas: mastication, deglutition and speech, and also
clenching and bruxism, as expressions of psychic
tension. In addition, the NMS of the masticatory
organ assumes a significant role in the posture of
the head.
The following muscles are involved in mastication
and deglutition: the true masticatory muscles,
muscles of the cranio-mandibular system, the mim-
ical muscles and the tongue, the floor of the mouth,
the musculature of the pharynx and the soft palate,
and the supra- and infrahyoid musculature, for con-
trolling the hyoid.
These functions have changed considerably in the
course of the last century, for a percentage of the
world's population. Modifications in the nutritional
habits of our industrial societies have effected a fun-
damental change in the masticatory organ. Because
of the extremely extended retention of the develop-
mental grooves in the dentition of modern humans
in the twentieth century, the functional programs
are infinitely more complicated than those of
abraded dentitions in the Middle Ages. In its con-
vergence, the latter corresponds to the mastication
pattern of herbivores, i.e., to a unilaterally or bila-
terally balanced articulation.
230
R. Slavicek • The Masticatory Organ
This organ, which had primarily served in the
ingestion of food in phylogenesis, was
redesigned into a multifunctional organ. 
The esthetics of the face is characterized by
the masticatory organ and its diversity,
dynamics and expression. 
Modifications in the nutritional habits of our
industrial societies have effected a fundamen-
tal change in the masticatory organ. 
Huber, E.: Evolution of Facial Musculature and Face Expression.
Baltimore: The John Hopkins Press, 1931
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231
Function - Mastication
Ill. 21: In fully developed
deciduous dentition, there is
still hardly any perceptible dis-
tance to the occlusal plane.
The ascending branch is
scarcely developed, the articu-
lar eminence is also merely
implied.
Ill. 22: On the development of
permanent dentition, the
ascending mandibular arch is
verticalized and its height
developes to an individual
extent.
Ill. 20: In the newborn, the
ascending branch is merely
implied; an imaginary occlusal
plane would pass through the
joint condyle.
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232
R. Slavicek • The Masticatory Organ
Ill. 27: The lateral view shows the gaps on
both sides.
Ill. 23: Gap opening because of hypo-plas-
tic smaller incisors, as compensation for the
full lower arch. Orthodontic closing of the
gap would be inappropriate.
Ill. 25: This sketch shows the closed arch
architecture of the mandible, with the
course of the incisal edges and cusp tips.
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233
Function - Mastication
Ill. 28: The lateral view shows the gaps
on both sides.
Ill. 24: Because of discrepancies in the size
of the widths of teeth, compensating arch
variations may emerge.
Ill. 26: The maxilla with its closed archi-
tecture and the positive buccolabial over-
bite.
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234
This alteration, brought about by the drastic
change in the range of available food products in
industrial societies, is multiplied by further factors.
In our century, humans live to be at least twice as
old. Psychological tension is on the increase,
brought about by the explosion of population and
media networking. This necessitates a fully new
phenotype, which the dentist at the turn of the
21st century will have to deal with and care for.
Statistical prognoses documented this dramatic
development (comp. Földy, Ringel).
The medieval abraded dentition was characterized
by contacting, functional convergence. The basic
principle of non-abraded dentition consists in the
avoidance of strong contact or continuous gliding
contact. Mastication with an abraded dentition
leads to considerably better processing of vegetable
food, but also to a considerably higher load on the
dental supportive system. The periodontal wear
and tear that we see in medieval dentitions applies
to age groups that correspond to the first third of
the life span of present day populations in industri-
al nations.
The complete functional area of the so-called mas-
ticatory organ of modern humans encompasses
mastication, speech, posture, esthetics and stress
management.
Mastication- definitions,
scientific discussion
"Mastication is the procedure of chewing food, the prepa-
ration for deglutition and digestion. Mastication is made
possible by the coordinated activities of the tongue, the
mandible, the masticatory muscles, the structural compo-
nents of the mandibular joints etc., controlled by the neu-
romuscular apparatus. The action of mastication is con-
cluded by deglutition."
The mutually complementing definitions given by
Bouchet, as mentioned above, describe the task as
the complexity of the directly involved structures. I
would express it more simply: 
Mastication is the life-sustaining function of pro-
cessing and ingesting food, as a prerequisite for its
digestion.
Ringel, E., Földy, R.: Machen uns die Medien krank?
Universitas Verlag,1992
Bouchet: Current Clinical Dental Terminology. Mosby 
(2. Edition), 1974
Mastication is the procedure of chewing food,
the preparation for deglutition and digestion.
Mastication is made possible by the coordinat-
ed activities of the tongue, the mandible, the
masticatory muscles, the structural compo-
nents of the mandibular joints etc., controlled
by the neuromuscular apparatus. The action
of mastication is concluded by deglutition.
In our century, humans live to be at least
twice as old. Psychological tension is on the
increase, brought about by the explosion of
population and media networking. 
R. Slavicek • The Masticatory Organ
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235
Function - Mastication
If we regard this function from the viewpoint of the
"masticatory organ" as a feedback-control mecha-
nism, the complex processes that occur at this site
become evident. All of the structures act in a coor-
dinated fashion. The mechanisms of detailed regu-
lation are especially interesting from a cybernetic
point of view. The complexities of the masticatory
function have been described by several authors
and recorded in even greater detail in the last few
decades, following the introduction of electronic
examination methods. Mandibular movements do
not correspond to the traditional images, as
inferred and taught by the use of so-called articula-
tors. According to the monograph, "Analysis of
Human Mandibular Movement", the authors
Goodson and Johansen, using ingenious electronic
methods, describe the mastication process as fol-
lows:
"The general appearance of a masticatory move-
ment is a highly refined, coordinated process.
Lateral (Bennett movement) and extreme protru-
sive movement of the condyles are the most con-
spicuous characteristics. The movement of the den-
tition (from intercuspation) is thereby almost verti-
cal, without signs of rotation around an inter-
condylar axis".
The separating and then protrusive movement in
the occlusal area, described above, would only be
possible with a strong rotation around the inter-
condylar axis, using an ordinary articulator. It is
significant that the predominantly translatory char-
acter of mandibular movement during mastication
is emphasized. A close look at the authors' results
brings a rather notable fact to light: the rotation
around the so-called hinge-axis of the mandible is
practically negligible in comparison to the three-
dimensional translation.
If we follow the results and conclusions of the
authors Gibbs and Lundeen in their numerous pub-
lications on the subject of mastication, the behavior
of the mastication pattern relative to dental struc-
tures is of special interest. The authors processed
the recorded patterns and displayed the movement
pattern of the mandible for the mandibular joints,
as well as for the dentition, taking into considera-
tion all six degrees of free mandibular movement.
The so-called gnathic replicator 1 from Charles
Gibbs, who was responsible for the conceptual and
technical design of the studies, allows for the
recording of mandibular movement by means of an
ingenious and practical arrangement of optical-
Mastication is the life-sustaining function of
processing and ingesting food, as a prerequi-
site for its digestion.
Goodson, J. M., Johansen, E.: Analysis of Human 
Mandibular Movement. Monogr. Oral Scien., 5: 1–80, 1975
Lundeen, H. C., Wirth, C. G.: Condylar Movement Patterns
Engraved in Plastic Blocks. J. Prosth. Dent., 30: 866–875,
1973
Lundeen, H. C., Shryrock, E. F., Gibbs, C. H.: An Evaluation
of Mandibular Border Movements. Their Character and
Significance. J. Prosth. Dent., 40: 442, 1978
Meyer, G.: Entwicklung und Anwendung eines elektronischen
Verfahrens zur dreidimensionalen scharnierachspunktbezüglichen
Registrierung von Unterkieferbewegungen für die
Funktionsdiagnostik des stomatognathen Systems. 
Dissertation, Göttingen 1986
"The general appearance of a masticatory
movement is a highly refined, coordinated
process. Lateral (Bennett movement) and
extreme protrusive movement of the condyles
are the most conspicuous characteristics. The
movement of the dentition (from intercuspa-
tion) is thereby almost vertical, without signs
of rotation around an inter-condylar axis".
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electronic transmitters and receivers, on a double
facebow system (ill. 29-31, p. 237). The facebows
were built ultra-light, were hardly a hindrance, and
were attached to the occlusion with rigid, function-
al occlusion wires. This made it possible for Gibbs,
Lundeen and co-workers to record the mastication
movements of volunteers and patients.
The occlusal plane was selected as the reference
plane for this method and the recordings were stan-
dardized to the individual occlusal planes of each
volunteer or patient. The apparatus allows the
investigator to execute the chewing test using var-
ious food qualities. Gibbs and Lundeen introduced
standardized research of the function of mastica-
tion. The apparatus is also distinguished by the fact
that, during the recording, the skillfully arranged
mounted models also moved in the "replicator",
with a time delay of 1:10, corresponding to the
recorded movement pattern. This movement of the
rigid model, which was mounted according to the
principle of the occlusal plane, resulted in entirely
new and surprising insights into the function of
mastication, which previously had not been exam-
ined systematically.
Diagrams of various views and overlays with denti-
tion schemes resulted in an unprecedented didactic
evaluation of the results. Lundeen and Gibbs made
their results available to schools and practitioners in
a completely open and an exemplary scientific
manner. I thank them most sincerely for their atti-
tude, which is by no means a matter of course in
current scientific research.
An especially interesting aspect of the study was
the possibility to shift the movements to individual
"occlusal tables" of the dentition (ill. 32-34, pages
238-239). A further noteworthy feature was the
display of masticatory movement in the joint,
which was achieved through the spatial possibility
of arrangement (ill. 35-36, p. 239). Joint move-
ments during mastication were, in fact, entirely dif-
ferent from those previously displayed in articula-
tors. In this new reality, the movement began with
a wide, symmetrical, anterior initial movement of
both condyles. This is reminiscent of the primitive,
first ingestion of food by the newborn, which acti-
vates the milking action in the same fashion.
The returning movement during mastication takes
place more quickly on one side and slowly on the
other, making the movement asymmetrical.
Apparently caused by the vectors of the muscula-
ture, this asymmetrical returning movement pro-
236
R. Slavicek • The Masticatory Organ
The occlusal plane was selected as the refer-
ence plane for this method and the recordings
were standardized to the individual occlusal
planes of each volunteer or patient. 
Lundeen and Gibbs made their results avail-
able to schools and practitioners in a com-
pletely open and an exemplary scientific man-
ner. 
In this new reality, the movement began with
a wide, symmetrical, anterior initial movement
of both condyles. 
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237
Function - Mastication
Ill. 30: The facebow on the
patient with the aid of a func-
tional occlusion attachment.
Ill. 31: Six cleverly applied
optical-electronic recorders
provide for the registration of
all the required information.
Ill. 29: The electronically con-
trolled machine replicates the
chewing activity of the subject
on the mounted models (time
delay of 1:10). The authors
selected the subject's occlusal
plane as the reference plane.
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238
R. Slavicek • The Masticatory Organ
Ill. 32: The mas-
tication move-
ments were over-
laid onto
mandible plots,
to allow for bet-
ter clarity and to
reveal the possi-
ble effects on the
occlusal surface
complex. Here,
the view from
the lateral 
perspective.
Ill. 33: An
occlusal view.
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239
Function - MasticationIll. 35: A time-delayed display of the joint track made it possi-
ble to study the elapsed time of the inherently asymmetrical
mastication cycles.
Ill. 36: Time-delayed view of the progress of a cycle in the left
joint.
Ill. 34: An anterior view.
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240
R. Slavicek • The Masticatory Organ
Ill. 37 (above, left): The right joint from a superior view.
Ill. 38 (above, right): The elapsed time of the left joint from a
superior view.
Ill. 39 (right): The lateral return as a novel finding, relative to
the Bennett movement.
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duces the classic, physical shift to the more rapidly
returning side, which can now be termed the lat-
erotrusion side (ill: 37-38, p. 240). The result of
this asymmetrical course is that the lateral teeth on
both sides achieve a favorable three-dimensional
functional antagonism. This physical shift of the
mandible during asymmetrical movements is
known as the Bennett movement; it was recog-
nized and observed very early in the literature (ill.
39, p. 240).
In contrast to the knowledge deduced from articu-
lator mechanics, which had traditionally been
taught up to this point, the Bennett movement
during mastication is a phenomenon of the return-
ing phase. Thereby, the condyle on the laterotru-
sion side leaves its cranial border position, swings
inferiorly, posteriorly and externally, generally fur-
ther back than its corresponding original position,
and then (and this was the remarkable new feature)
returns to its original position with a cranial, inter-
nal, superior movement. The contralateral side
moves more slowly in the returning movement but
remains rather cranial, relative to the border track,
and oriented towards the articular eminence. The
conformity to biomechanical laws is clearly seen in
the excellently labeled time frames on the graphic
display.
From the viewpoint of the Bennett movement,
termed "side-shift" in current dental language, it is
actually an "in-shift" of the condyles, taking place
during the returning phase, centering to the mid-
dle from a lateral position. This swinging return
movement is always associated with active control-
ling processes of the muscles in the cranio-
mandibular system. These are coupled in a "closing
active" and meaningful fashion with the controlling
temporal muscle.
If we regard the same from the viewpoint of the
articulators and transfer the movement to the den-
tition, as didactically proposed in the publication
by W. McHorris, the movement takes place exter-
nally (ill. 40-41, right). This does not hold true for
mastication. A movement of this kind would more
likely take place during the parafunction of eccen-
tric bruxism. The section on Parafunction will deal
with the extent to which a Bennett movement
actually exists.
If we look at the diagrams of typical mastication,
with regard to mandibular incisor movement, the
drop-like shape of the cycle, viewed anteriorly, is
241
Function - Mastication
McHorris, W.: Einführung in die Okklusionslehre. 1983 
Ill. 41: The spatial dependence of joint movement to occlu-
sion, which Bonwill had already termed articulation, in the
overview display from McHorris.
Ill. 40: The conception of occlusion from the viewpoint of
protection in parafunction in the articulator.
A movement of this kind would more likely
take place during the parafunction of eccen-
tric bruxism. 
Bennett movement
Side-shift
Immediate Side-shift
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conspicuous. A similar phenomenon was published
in 1912 by Zsigmondy, based on self-observation
(ill. 43, p. 243).
A significant result of the research on the mastica-
tion cycle performed by Gibbs and Lundeen is the
fact that the anterior teeth are avoided during mas-
tication, i.e. they do not make contact. Worthy of
note is the fact that mastication patterns are rapid
movement cycles without a high expenditure of
energy (ill. 42 and 44, p. 243).
Using a mathematical model publicized by Lugner
and myself, we will attempt to clarify the biome-
chanics with the aid of a sagittal scheme. Anterior
teeth are not used as gliding teeth on the lingual
surface but rather, in the sense of a moderate avoid-
ance mechanism, functionally programmed in a
way that they act as borders of movement without
colliding contacts, and simultaneously allow for the
closest possible convergence. On the other hand, in
the sagittal scheme, it is the synovial gliding joint
that offers the possibility of mathematically regis-
tering a corresponding protrusive sliding move-
ment (symmetrical initial movement) (ill. 45-47, p.
244). These two inverse concavities are arranged
and coordinated into the same coordinate system.
The mandibular joint movement is taken as an
even, gliding movement, without a change in
speed. Therefore, the marking points of the elapsed
time are each taken on the joint track at the same
intervals, resulting in a constant rate of speed for
the joint. In contrast, the coupled movement caus-
es an alternating speed to occur in the anterior
tooth area and the elapsed time is irregular. This
can be seen in the different marking distances.
If we analyze the different speeds of the two oppo-
sing curves, it becomes evident that the speed in
the anterior area during constant speed in the flat
area, relative to the joint's gliding speed, is slow at
first, and then increases in the steeper portion. This
is expressed in the increasing distance between the
numbered time points. 
In this kind of sagittal model, it is naturally also
possible to follow a point in the area of occlusion,
e.g., the first mandibular molar, in its spatial geo-
metry and/or in elapsed time. The hinge-axis
orbital plane, and not the occlusal plane used in the
studies of the Gibbs and Lundeen team, serves as
the coordinate system. Applying this in real exam-
ples and comparing the lingual concavity of the
subject's anterior tooth section to the sagittal joint
track, it is possible to create a mathematical model
242
R. Slavicek • The Masticatory Organ
Zsigmondy, O.: Über die Bewegungen des Unterkiefers beim
Kauakt. Österr. Zschr. f. Stomatol., X (6): 175–184, 1912
Slavicek, R., Lugner, P.: Der schädelbezügliche teiladjustierbare
Artikulator. Österr. Zschr. f. Stomatol., I u. II: 84–102 und
122–142, 1976
Slavicek, R., Lugner, P.: Über die Möglichkeit der Bestimmung
des Bennettwinkels bei sagittaler Aufzeichnung. Österr. Zschr. f.
Stomatol., 7/8: 270–284, 1978
A significant result ... the anterior teeth are
avoided during mastication.
These two inverse concavities are arranged
and coordinated into the same coordinate sys-
tem. 
Therefore, the marking points of the elapsed
time are each taken on the joint track at the
same intervals.
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243
Function - Mastication
Ill. 43: Self-observation
in the mirror in 1912,
resulted in practically
similar loops as those
obtained from elec-
tronic recordings.
Ill. 42: Recordings in
the three observation
planes show, especially
in the anterior view,
the drop-shaped masti-
catory loops, whose
lateral aspect appears
considerably less
bunched than in the
sagittal view.
Ill. 44: Note that, dur-
ing mastication, no
incisor contact takes
place.
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244
R. Slavicek • The Masticatory Organ
Ill. 46: Calculation of the
declining track on the anterior
tooth.
Ill. 47: Condylar track of the
same subject in the same coor-
dinate system.
Ill. 45: The inner surface of an
anterior tooth, divided into two
sections.
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of the geometric processes, along with all the
resulting consequences. Of special interest here is
the rotational behavior of the hinge-axis during the
movement.
Example 1 (ill. 48-49, p. 246) shows the combina-
tion of anterior and posterior components of a
healthy subject. It is noticeable that, at the begin-
ning, the hinge-axis shows a minimal initial closing
rotation of just a few tenths of a degree.
Subsequently, an equally minimal opening rotation
occurs. Because of this process, this is an extremely
economical movement for the NMS, characterized
by translatorycomponents alone.
If the inclination of the anterior teeth is artificially
changed in the model by tipping it forward by 15
degrees (ill. 50-51, p. 247), the behavior of the
hinge-axis changes very little. If, in this example,
the movement of the contour of the anterior teeth
follows, a more distinct closing rotation takes place
and fails to reach the original value even if the
movement continues to the incisal edge. The possi-
bility of molar contact becomes a probability in this
model, if one includes an occlusal plane with aver-
age inclination into the diagram. In a further exam-
ple, if the vertical overbite of the anterior teeth is
reduced (ill. 52-53, p. 248), the controlled course in
the area of the mandibular joints is also reduced
and a moderated opening movement is initiated
immediately through the inclination of the steeper
portion of the anterior concavity, which, however, is
only briefly controlled.
In the next example (ill. 54-55, p. 249), the anteri-
or tooth is tipped back. The entire lingual concavi-
ty exercises dominant guidance control. It is evi-
dent that an initial opening movement takes place
in the sagittal scheme, characterized by strong rota-
tion.
This initial opening movement is not determined
by translation, but by rotation. This means that, if
this course of movement came about, the move-
ment would have to take place predominantly in
the inferior joint. The absence of translation near
the occlusion would strongly reduce the breaking-
up and tearing efficiency of mastication. In the
actual reality of complete overbite, this is not the
case at all; the mastication pattern "avoids" the oth-
erwise mandatory strong rotation, with a predomi-
nantly transversal movement.
It should be pointed out here that the combination
of the anterior and posterior guidance components
245
Function - Mastication
Of special interest here is the rotational behav-
ior of the hinge-axis during the movement.
Because of this process, this is an extremely
economical movement for the NMS, charac-
terized by translatory components alone.
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246
R. Slavicek • The Masticatory Organ
Ill. 49: In this combination, the rotational behavior is decisive. This kind of combination refers to almost pure translation, except for
a few tenths of a degree.
Ill. 48: The anterior tooth concavity and condylar track in dynamic interdependence. In between: a possible molar path.
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247
Function - Mastication
Ill. 51: The overall behavior still remains translatory.
Ill. 50: This illustration makes the interdependence clear: the change in inclination of the anterior tooth, by tipping it forward, also
changes the molar track.
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248
R. Slavicek • The Masticatory Organ
Ill. 53: The behavior is now rather rotational.
Ill. 52: The mathematical models demonstrate how the reduction of the vertical overbite results in a reduced controlled condylar
excursion.
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249
Function - Mastication
Ill. 55: If the pattern progressed sagittally, it would require strong rotation.
Ill. 54: An increase in the inclination of the anterior teeth and a simultaneous flattening of the joint track would lead to entirely dif-
ferent overall behavior.
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is apparently very important for muscle and joint
physiology. The consistency of the two inclinations
means that the main function of mandibular move-
ment would have to be predominantly translatory
in one case, but more rotational in another, because
of discrepancies. In order to avoid an overly strong
opening rotation (as pointed out in the example of
complete overbite), the function would have to be
rather transversal in cases of especially steep front
components or narrowing of the mandibular arch
by the maxillary arch. This results in considerably
more complex demands on the overall muscula-
ture, instead of the simple, translatory, anterior-
posterior movement.
Influencing mastication through anterior guidance-
or controlling components of the front canine
group is not limited to the dentulous situation. In
a study of chewing patterns, the researchers from
Innsbruck, Tscharre-Zachhuber and Riedl, under
the direction of Gausch, examined wearers of full
dentures with regard to the effects of a change in
the front area. Since 1974, the Innsbruck
University Dental Clinic under Gausch has set up a
dominant canine as the control tooth in the other-
wise rather balanced concept of lateral tooth
arrangement, according to Gerber. After being
applied hesitantly in the beginning, this theoretical
model gained increasing general acceptance and is
now established in education as the Innsbruck
Concept of Gausch.
In further studies by the two authors, the examina-
tion of mastication muscles with the sirognatho-
graph showed that a definite change in the frontal
mastication pattern results when this kind of steep-
er tooth is installed in an otherwise flat occlusal
concept. The authors examined and compared per-
manent, reconstructed occlusions which were
waxed up with controlled canine guidance. The
reconstructed occlusions originated from Professor
Kulmer, who documented them minutely during a
long-term study carried out in a group of subjects
with full dentures. They were recorded before and
after a change in the canine arrangement.
Surprisingly, the results were strong changes in the
behavior of the pattern and a frontal mastication
loop pattern comparable to a dentulous situation
which, with an avoidance angle of approximately 8
to 10 degrees and a canine inclination of approxi-
mately 40 degrees, created a mastication pattern
fully appropriate to a dentulous, rehabilitated
patient (ill. 56-64, pages 252-253; many thanks to
250
R. Slavicek • The Masticatory Organ
Tscharre-Zachhuber, Ch., Riedl, M. A.: Kaumusterunter-
suchungen von Totalprothesenträgern. Jaw Movements in Patients
with Full Dentures. Zschr. f. Stomatol., 85 (7): 423–428, 1998
The consistency of the two inclinations means
that the main function of mandibular move-
ment would have to be predominantly trans-
latory in one case, but more rotational in
another, because of discrepancies. 
After being applied hesitantly in the begin-
ning, this theoretical model gained increasing
general acceptance and is now established in
education as the Innsbruck Concept of
Gausch.
Influencing mastication through anterior
guidance- or controlling components of the
front canine group is not limited to the den-
tulous situation. 
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251
Function - Mastication
Innsbruck for the pictures).
Mastication should be more and more a purely
translatory movement pattern with minimal rota-
tion during the phase of bolus formation. For
dynamic mastication of optimal quality, modern
human dentition should achieve the closest possible
convergence of the dentitions, without functional
interferences among the teeth or groups of teeth.
Conclusions
Assuming that occlusion is the dominant deter-
mining factor of the system, based on the above
mentioned statements I arrived at the following
conclusions:
Anterior teeth are always strictly avoided during
mastication! They are to be regarded as functional
interferences during mastication.
Canines, and also other teeth in the lateral tooth
area, are sometimes touched lightly and fleetingly
during mastication. These appear to be orientation
contacts for the rapid, sequential movements of the
chewing mechanism. The informative canine con-
tacts can determine the functional pattern in a fixed
restoration, and also seem to function in the same
way in persons wearing full dentures. Informative
contacts during mastication can also take place on
other teeth, depending on the individual. They are
pattern-specific and may lead to discrete facet for-
mation.
These functional facets are to be strictly differenti-
ated from parafunctionally created abrasions, as
they are generally not so strongly distinguished and
are in no way as glossy as active parafunctional
facets. They are isolated and have no other equiva-
lentmasticatory organ and its unique interrela-
tionship with the more highly developed brain,
now in concert.
The Scientific Discussion
Charles Darwin left a strong impression on biolo-
gy in the nineteenth and twentieth centuries, with
his evolutionary theory of adaptive progress up
the ladder of racial development. This is especial-
ly evident in discussions on human phylogeny.
Purist insistence on exclusivity in the develop-
ment of the species, as in Phyletic Gradualism,
assumes that different species populating the
same territory, according to sympatric continuity,
underwent slow and adaptive evolution in the
classical Darwinian sense. Hybridization and
interbreeding among similar species did not take
place. Each species is considered to be a distinct
population and a specific genetic system. In the
Darwin-Wallace scheme, biological species are
regarded as "evolutionary units".
The recognition and occupation of available
niches through adaptive behavior, as defined by E.
Mayr, is the ideological foundation of the concept
of "Phyletic Gradualism" in the development of a
species. From this point of view, regarding the
19
Evolution
Darwin, Ch.: On the Origin of Species by Means of Natural
Selection. London 1859 (dt.: Die Entstehung der Arten
durch natürliche Zuchtwahl. Stuttgart 1867)
Emergence means the "sudden appearance" of
something principally new and unprecedented. 
The entirely new features of mankind are
intimately connected to the masticatory organ
and its unique interrelationship with the
more highly developed brain, now in concert.
... according to sympatric continuity, under-
went slow and adaptive evolution in the clas-
sical Darwinian sense. 
Emergence
Sympatry 
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emergence of differing alleles in a homologous
chromosome array, sub-populations with minor
phenotypic differences emerged and were able to
establish themselves, in isolation, over a long peri-
od of time. Mayr also recognized the advantage of
the isolation of such a sub-population, because
isolates were removed from the gene flow of the
general population, which can result in more
rapid and efficient speciation; however, he insists
on the principle of gradualism. Under the pressu-
re of external selection mechanisms (the Synthetic
Theory views "selection" as the determining force
in evolution), these sub-populations represented a
preliminary stage of speciation, provided they
were able to persist and gradually adapt. These
kinds of sub-populations tended to exist in homi-
nid development, but all of the branches were
characterized by unusually static evolutionary
behavior, although, at the time, the exceptionally
low population density would have favored the
principle of isolation, or at least increased its like-
lihood. There is a paucity of evidence to indicate a
step-by-step continuity leading up to "Homo". In
actuality, a great number of these preliminary sta-
ges in the gradual evolution from Australopithecus
were unsuccessful.
The dogmatism of representatives of classic
Darwinism and its derivatives (Neo-Darwinism
and Synthetism) could not alter the fact that the
principle of secondary adaptation to altered con-
ditions left many questions unanswered. Above
all, the time factor involved in the assumption of
a purely adaptive form failed to provide answers
to existing questions and even raised new pro-
blems. Because of these contradictions and open
questions, new evolutionary theories disputing
the Darwin-Wallace hypotheses appeared.
Apparently, nature is liable to discard the gradual,
risk-free path of gene-point mutation in phyletic
development, which is subject to adaptive control,
in favor of a very risky "more active" path in gene
regulation and chromosome mutation. For various
reasons, Eldredge and Gould dispute the "soft"
biological model of phyletic gradualism as the
"norm" in the development of a species and postu-
late instead their hypothesis of "punctuated equi-
librium". According to this hypothesis, erratic dis-
continuities in speciation followed long periods of
evolutionary "near stagnation". This abrupt clado-
genesis leap within an existing species was an
20
R. Slavicek • The Masticatory Organ
The evolutionist is fully convinced that he has
found an entirely satisfactory solution to the
basic problem of evolution in Darwin's theory.
(E. Mayr)
There is a paucity of evidence to indicate a
step-by-step continuity leading up to "Homo". 
Mayr, E.: Animal Species and Evolution. 1963 
(dt.: Artbegriff und Evolution. 1967) 
Mayr, E.: aus Wuketits, F. M.: Evolutionstheorien/
Dimensionen der modernen Biologie 7, Evolutionstheorien.
S. 171, Darmstadt 1988
Mayr, E.: ... und Darwin hat doch recht. Piper Verlag,
München 1994
Eldredge, N., Gould, S. J.: Punctuated Equilibria: An 
Alternative to Phyletic Gradualism. In: Schopf, T. J. M.
(ed.): Models in Paleobiology. S. 82–115, Freeman, Cooper,
San Francisco 1972
Every species is a finely integrated genetic sys-
tem, which has been selected, over a period of
many generations to fit into a particular niche
within its environment. (E. Mayr) 
Phyletic Gradualism
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exceptionally rapid one in comparison to normal
evolutionary time periods. The probability of such
rapid change was due to the possibility of strong
imbalances, based on the formation of peripheral
isolates and the resulting allopatric speciation.
The formation of such isolated groups was favor-
ed by the exceptionally low population density at
the time. Because of their special characteristics,
peripheral isolates had the opportunity to esta-
blish themselves genetically. Allopatry in this con-
text means that there was no similar or very simi-
lar species in the territory. This provided an
opportunity to develop, test and reproduce new
characteristics, functions and structures in a prac-
tically "non-competitive" environment. After a
period of consolidation, upon renewed contact
with the original species, they would have the pos-
sibility to preserve their genetic continuity, even
to the extent of becoming competitors of the ori-
ginal species. If one of these types of isolated
populations actively took advantage of the oppor-
tunity, it would not have been occupying an avai-
lable niche through adaptation, but would have
been creating one of its own!
Being expelled from the horde because of their
"different-ness" might have signified death for the
outcasts - but might also have meant a new
opportunity. Myths throughout mankind's history
are replete with examples. This activity of life is
not an adaptive fight for survival, but a striving
towards something new and higher. Here I would
like to refer to Popper's statement to Lorenz
during their discussions in Altenberg. The possi-
bility of rapid speciation, described above, is
named "Punctualism" by its authors. An additio-
nal possibility of speciation would be the comple-
te abandonment of adaptive control mechanisms,
as postulated in Saltationism. In this case, causal
large-scale mutations took place, and allowed
evolutionary leaps to occur. In a hypothetical way,
Carson points to such an extremely risky approach
to speciation. A promising "hopeful monster" that
came into being this way would not choose the
road of adaptive examination; he would "reprodu-
ce" and subject himself to the merciless control of
his own ontogenesis.
21
Evolution
"Life forms without initiative, curiosity, fanta-
sy, must fight for ecological niches that are
already occupied. However, those with initia-
tive have created new ecological niches for
themselves. And, the interesting thing is that,
from the beginning, ecological niches have
been made by life forms." Dialogue between
Popper and Lorenz (Altenberg)
Popper, K. R., Lorenz, K.: Die Zukunft ist offen (Das
Altenberger Gespräch). Serie Piper, München 1985
Lorenz, K.: Die acht Todsünden der zivilisierten Menschheit.
Piper Verlag (18. Auflage), München 1985
Carson, H. L.: The Genetics of Speciation at the Diploid
Level. In: Amer Nat 109, S. 83–92, 1985
…it is altogetheror counterpart that can be achieved in an artic-
ulator.
The mastication cycle is clearly dependent on the
inclination of the lingual contours of the maxillary
dentition. This appears to affect the incursive mas-
tication loop of the laterotrusion side. It justifies the
conclusion that the hard dental substance that is
apparently the guidance which represents the
steepest interferences to free movement, deter-
mines the mastication pattern. This, in turn, leads
to the conclusion that mastication patterns are the
consequences and results of functional interferences
Mastication should be more and more a pure-
ly translatory movement pattern with mini-
mal rotation during the phase of bolus forma-
tion. For dynamic mastication of optimal
quality, modern human dentition should
achieve the closest possible convergence of
the dentitions, without functional interfer-
ences among the teeth or groups of teeth.
Anterior teeth are always strictly avoided dur-
ing mastication! They are to be regarded as
functional interferences during mastication.
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252
R. Slavicek • The Masticatory Organ
56 (right): The representation of a mastication loop
according to Gibbs. The authors Tscharre-Zachhuber,
Riedl and Gausch attempt the cognitive construction of
the mastication loop using canine guidance.
57 (below): Comparison of the mastication loops of a
rehabilitated patient with a fixed restoration to an aver-
age full denture wearer.
58: Canine control in a dentulous subject. 59: Experimental canine control in full denture subject.
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253
Function - Mastication
63: Mastication loop of a rehabilitated patient with a
fixed restoration.
64: Mastication loop of a conditioned full denture
patient.
62: Examples.
60: Success after 2 weeks. 61: Left-sided exercise loop after a few weeks.
www.ajlobby.com
in the dentition in a free mandibular movement.
This kind of behavior in the mastication cycle was
recognized early and documented from self-obser-
vation.
Prerequisites that the human stomatognathic sys-
tem must fulfill in order to be appropriate for the
function of mastication have been previously men-
tioned. The prerequisites must be the goals of ther-
apy for the dentist when he/she is called upon to
alter occlusion for therapeutic purposes. The pri-
mary goal of any reconstruction is to achieve the
most even convergence of the dentition without the
appearance of interferences.
From the viewpoint of mastication, the characteris-
tic concept of "disocclusion" has perverted the actu-
al purpose of the masticatory organ, i.e. grinding
food as efficiently as possible. The creation of mod-
ern occlusion concepts has been determined more
by thoughts of safety with regard to parafunction
than by allowing for the fact that food must be pre-
pared appropriately for digestion. This is rather
counterproductive at a time when the concept of a
vegetarian diet is gaining increasing acceptance.
The quality of occlusion must be evaluated accord-
ing to whether an interference-free, maximum con-
vergence of the dental arches to each other during
mastication is achieved. This is inordinately more
difficult when dealing with the dentition of modern
humans, which is not subject to abrasion, than with
the abraded dentition of the past. With regard to
dynamics, this requires that the cusp-carrying den-
tition be movable translationally, evenly separated
and without interference. The distance must be as
minimal as possible, in order that the individual be
able to tear up and grind food. Mastication must be
more and more translatory during the phase of
bolus formation, with minimal rotation. This is also
the optimal physiological constellation for the syn-
ovial joints of the CMS, because joint lubrication
functions optimally during the extensive move-
ment and continuous fluctuation in joint pressure.
This ensures the inner metabolism of the joint cav-
ities. It is also most economical for the musculature,
which becomes active isotonically, predominantly
through the protractors and retractors. Elevators
and distractors only execute a precisely controlled
positioning function of vertical separation.
In reiteration of the sequence of movement in the
mastication cycle, it begins with a protrusive, sym-
254
R. Slavicek • The Masticatory Organ
This, in turn, leads to the conclusion that
mastication patterns are the consequences and
results of functional interferences of the den-
tition in a free mandibular movement. 
From the viewpoint of mastication, the char-
acteristic concept of "disocclusion" has per-
verted the actual purpose of the masticatory
organ, i.e. grinding food as efficiently as pos-
sible. 
The quality of occlusion must be evaluated
according to whether an interference-free,
maximum convergence of the dental arches to
each other during mastication is achieved. 
This ensures the inner metabolism of the
joint cavities. 
Disocclusion
Metabolism
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metrical, initial movement. This lies within the
temporo-mandibular joints on the cranial border.
The asymmetry of the movement begins incursive-
ly. The condyle of the laterotrusion side swings
more rapidly to posterior and then, as a rule, later-
ally and caudally, the extent depending on the indi-
vidual and influence from the kind of food. The
condyle on the mediotrusion side follows with some
delay, remains closer to the border track, and
swings to medially. There follows, on the laterotru-
sion side, the renewed inward swing between the
mandibular dentition from posterior-inferior to
anterior-superior, against the maxilla. Thereby, the
two sides are brought again into symmetry and the
symmetrical initial movement begins anew. The
movements take place nearer to border track of the
temporo-mandibular joint when the quality of the
occlusion is better. Mastication is concluded by
deglutition. The functional tracks are also easy to
record and evaluate diagnostically, through the use
of electronic recordings of joint movements and
appropriate fixation of the apparatus.
The practical morphology of the articular eminence
(a convex trochlea with initial inclination in front of
the cylindrical joint processes), in conjunction with
the interposed articular disc, produces a good struc-
ture, suitable for meeting these requirements.
Through this synchronization, the equally practical
intercoronal free space formed by the maxillary
front teeth with their lingual concavity during the
initiating mandibular movement to allow for the
two inclined surfaces to be free from each other,
which is a prerequisite for a predominantly transla-
tory mastication function. This can be demonstra-
ted with geometrical-mathematical models, but it
must be mentioned, as a point of criticism, that the
mechanistic model which attempts to force the free
system of mandibular movement into a theoretical
corset through the crankshaft principle (comp.
Kubein-Meesenburg, Nägerl) does not correspond
to the biomechanics of the masticatory organ.
It must also be reemphasized that mastication is by
no means a tooth-guided, gliding movement, but
rather an extensively free muscular pattern deter-
mining mandibular movement. The muscular pat-
tern is interrupted by fleeting non-emphatic con-
tacts of particular teeth. The contacts are proprio-
ceptive informational ones for the fine control of
the chewing movement, and are adjusted to the
current consistency of the bolus. From the frontal
view, the cusp inclinations determine the inclina-
255
Function - Mastication
The practical morphology of the articular
eminence (a convex trochlea with initial incli-
nation in front of the cylindrical joint
processes), in conjunction with the interposed
articular disc, produces a good structure,
suitable for meeting these requirements. 
It must be mentioned, as a point of criticism,
that the mechanistic model which attempts to
force the free system of mandibular move-
ment into a theoretical corset through the
crankshaft principle (comp. Kubein-
Meesenburg, Nägerl) doespossible that the processes
(leading to) the development of a species
could be initiated by a series of random, cata-
strophic genetic processes, as a result of
forced reorganization of disorganized epistat-
ic super-genes.
Myths throughout mankind's history are
replete with examples. 
Cladogenics
Allopatry
Punctualism
Ontogenesis
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R. Slavicek • The Masticatory Organ
The new species "Homo"
Returning to human development, we find that,
in an extremely short time span in relation to the
entire history of development, an unprecedented
change in favor of morphological "different-ness"
took place. A new species emerged. A significant
portion of the morphological differentiation of
this species affected the masticatory organ. The
evolutionary functional adaptation of the hominid
masticatory organ into a communicative organ on
a higher level required preparation of the appro-
priate brain functions. The evolution of the masti-
catory organ is closely linked to brain develop-
ment. It is possible that the brain had sections
that were prepared in an anticipatory fashion. In
other words, during hominid evolution, cortical
areas of the brain were "recruited" and "prepared".
Hominid speciation did not lead to immediate
further development, but to a long period of evo-
lutionary stagnation. The Australopithecus africa-
nus (see ill. 1, 2, 3a, 3b, left) survived as the gene-
carrying species for millions of years, with just a
few slight ramifications in terms of phenotypes
(see ill. 4, p. 23). To exaggerate, according to
Dawkins, the hominid, as a species, functioned as
the gene survival machine in the contest for gene-
tic survival.
Suddenly, after millions of years, a dramatic gene-
tic change took place and Homo habilis crossed
the line from hominid to Homo. This may be
regarded as an explicit example of "punctuation"
(see ill. 5-7, p. 23).
Returning to the masticatory organ, the path
towards the new species "human" means that,
because of the complete readjustment of functions
within a very short period of phylogenic time, we
may use the morphological concept described by
Goethe and Burdach, which is the conceptual unit
of "form and function", and apply it in its full
scope to the "new" masticatory organ". Of special
note in this case is the fact that a patently new or
expanded function emerged as a result of the spe-
cies actively making use of an altered organic
morph to build up a different expanded "commu-
nication". This new function leads to speciation
and to its own establishment.
Further development of the "speech" function
confirms the altered form of the masticatory
22
Ill. 3a and 3b: The angle of separation of the lower jaw in
chimpanzees is parallel to slightly negative, but distinctly
positive in Australopithecus, because of the condylar distance.
The form of their jaws is entirely different. 
Ill. 1: The short "flat-faced" terrestrial Australopithecus
africanus was the gene carrier of the human race for millions
of years.
Ill. 2: The brain weight of the Australopithecus africanus in
relation to the brain weight of modern humans.
Homo habilus-phylogenesis
Species-Homoid-Hominid
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Evolution
23
Ill. 7: … with varying brain volumes.Ill. 5: Homo habilis, the "skillful one",
the "handy one", ends the evolutionary
stagnation with his special characteristics.
He successfully makes use of his "quali-
ties" : the hand, brain, and communica-
tion.
Ill. 6: The relative brain weight of Homo
habilis is markedly increased …
Ill. 4: As the latest findings show, there were no or only minimal regional changes over a period of millions of years.
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R. Slavicek • The Masticatory Organ
24
Ill. 8: Note the vertical position of the foreface of the orang-
utan when he walks on the ground.
organ and leads to further modifications through
structural changes in the skull associated with the
brain. The concept of evolution, the creation of
something new, the "concept of creation", can be
justifiably applied here. This is the beginning of
an extremely active period in the "creation" of an
ecological niche for "Homo".
The prepared areas of the brain, mentioned above,
were initiated and developed rapidly and dramati-
cally through the evolution of communicative
speech. Verbal communication created the higher
level of the Buehler-Popper speech model. Brain
volume increased rapidly and consistently from
this point onward. Other ramifications of the
hominid species stagnated and became extinct.
Even the gene-carrying Hominids, Dawkins'
"gene survival machine", ceased to exist at this
point and eventually died out.
It was the descriptive and argumentative func-
tions of this new speech that exponentially accele-
rated the dramatic development. In a later chap-
ter we will elucidate a hypothesis regarding the
enormous influence of the masticatory organ
through its speaking ability being advanced, and
the evolution of the brain as a result of the gro-
wing ability to communicate.
An evolutionary "rapid" change to upright postu-
re and to bipedal locomotion took place at the
time when the new form of communication deve-
loped. The altered posture had already been intro-
duced by Australopithecus and was certainly faci-
litated by the modified viscerocranium. Common
illustrations of the cranium of pongids and
Australopithecus are both false and misleading, as
they do not represent the actual body-head postu-
re of living individuals, but are based on traditio-
nal, incorrect comparisons (see ill. 9-11, p. 25).
Homo stood up and became a two-legged being.
At first, this process affected the pelvic girdle, the
spinal column and the proportions of the extremi-
ties. Upright posture had lasting effects on the
entire postural apparatus, especially on the head
(see ill. 12-14, p. 26). In a physiological position,
terrestrial primates are not "pro-", but "vertigo-
gnathic", because of the field of vision they requi-
re (see ill. 8, left). The forehead of an adult chim-
panzee or a gorilla hangs down to a certain extent.
Therefore, dramatic requirements for upright
posture affected the entire cranial skeleton, espe-
cially the sphenoid, temporal and occipital bones,
Organisms are machines for (the purpose of)
gene survival. (R. Dawkins)
Even the gene-carrying Hominids, Dawkins'
"gene survival machine", ceased to exist at this
point and eventually died out.
Dawkins, R.: The Selfish Gene. Oxford University Press,
Oxford 1976 (dt.: Das egoistische Gen. Springer Verlag, 
New York 1978)
Viscerocranium
Prognathia
Verticognathia
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Evolution
25
Ill. 9: This prognathic depic-
tion of a primate skull does
not correspond to the reality of
optionally or primarily terres-
trial anthropoids. The field of
vision, in the shown position,
would not allow the individual
to view the ground.
Ill. 10: This comparative illus-
tration of a gorilla skull with
that of Australopithecus is
false and needs to be corrected
(see illustration below).
Ill. 11: Accurate comparison of
skulls; the short foreface of the
hominid allows for distinct
backward rotation of the crani-
um, as an expression of the
cladogenic change in posture.
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R. Slavicek • The Masticatory Organ
26
Ill. 14: The process of standing upright affects the pelvic girdle, the spinal column and proportions of the extremities. The "freeing"
of the hands is an important evolutionary process. The ligamentary attachment of the primate skull is modified to afford the "bal-
anced head" of humans.
Ill. 12: The term “Homo erectus“ expresses the breakthrough to becoming a
true biped.
Ill. 13: Simultaneously, the volume of the
brain increases. It comprises approximately
70% of that in modern humans.
Homo erectus
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Evolution
27
which deserve special attention. This point will be
dealt with in greater detail later by viewing struc-
tures during the dramatic ontogenesis of children,
who eventually attain upright posture (compare
ill. 15, right). 
Evolutionary hypothesis regardinghominization, relative to the 
masticatory organ 
The hypothesis presented and discussed here may
be formulated as follows: One of the most impor-
tant pre-conditions for hominization was the exi-
stence of morphological prerequisites for oral
communication. The prerequisites were achieved
by means of a cladogenic alteration in the form of
the dental arch, probably a random evolutionary
occurrence. At the same time, the recession of the
viscerocranium resulting from retention of the
"child-like" arch form, and the concurrent increa-
singly upright posture simplified laryngeal control
of the highly refined, ventral muscle group of the
throat.
A specific change in the functional range of the
upper cervical spine took place, relative to control
of the head and head posture. The respiratory pas-
sages and, most likely, the prepared areas of the
hominid brain, attained "the ability of speech".
The dominant pongid canine which, especially in
males, was prominent and separate, dominating
the upper arch, remained integrated in the dental
arch, and the primate gap between the upper
canine and the front teeth did not develop during
growth. Gender-related differences in dental
arches became minimal. The masticatory organ
became more suitable as an organ for speech
because of changes in the architecture of the den-
tal arcade and the reduction of canine dominance.
This capability was utilized and the value of more
abstract communication was appreciated. The
increasing ability to express one's knowledge,
developed on the basis of the available language,
created the possibility of "articulating" and pas-
sing on one's knowledge. This led to being able to
add others' experiences to one's own and vice
versa, and thus create, exchange and pass on know-
ledge. This permitted consistent development of
Ill. 15: The muscular balance of the human skull on its artic-
ular surfaces. The increases in brain volume are fully achieved
in the Neanderthal. There is no further change.
The respiratory passages and, most likely, the
prepared areas of the hominid brain, attained
"the ability of speech".
This capability was utilized and the value of
more abstract communication was appreciated. 
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R. Slavicek • The Masticatory Organ
the brain, leading to the evolution of Homo into
Homo sapiens. Such development of the brain
may have already been prepared in anticipation,
through preformed but unused centers. Using the
symbols of a transmitter and receiver, the deve-
lopment of speech (transmitter) must lead to con-
current functional adaptation of hearing (receiver)
and the new function, namely understanding.
This hypothesis postulates that the "capability"
(not the ability) of speech, that is, the morpholo-
gy of the masticatory organ for speech, is the pre-
mise for brain development. The development of
a new species and its cladogenic determination
were rendered possible by "punctuated equilibria"
and probably by the emergence of so-called peri-
pheral isolates, as indicated by Eldredge and
Gould. Thus, the human masticatory organ did
not emerge as a result of the slow, adaptive pro-
cess and the secondary effects of selection mecha-
nisms in the sense of phyletic gradualism. The for-
mation of peripheral isolates caused an allopatric
principle to emerge, possibly based on stochastic
individuals, i.e., "random" phenotypes of a few
individuals. Because of their isolation, these "ali-
ens" had an opportunity to develop and consoli-
date their new characteristics with no competiti-
on, and they took advantage of the opportunity.
The most important modifications affected the
brain and the masticatory organ, including the
development of communicative speech.
At this point we must compare the stochastic
"Non-Concept" of the Trial and Error Principle
and the "Random" concept of creation, as attemp-
ted by Eccles in his work "The Evolution of the
Brain - the Creation of Self", and in his dialogue
with Popper. Comparing the two possibilities
would give rise to a discussion concerning the dif-
ferent paths toward hominization. From the point
of view of the proposed hypotheses, the second
possibility appears both, more active and more
probable. "Speech is brain - Brain is speech", as
Popper said!
In contrast to Darwin, the involution of the canine
is not a result of an intelligence-based capability to
trade off bodily weapons for tooled ones, but rather
the formation of random peripheral isolates equip-
ped with variations, possibly with a somewhat dif-
ferent masticatory organ including retrognathic
jaws with smaller canines and a more erect posture,
compelled by their smaller size, along with additio-
28
"Speech is brain - Brain is speech"
This led to being able to add others' experi-
ences to one's own and vice versa, and thus
create, exchange and pass on knowledge. 
Eldredge, N., Gould, S. J.: Punctuated Equilibria: An
Alternative to Phyletic Gradualism. In: Schopf, T. J. M.
(ed.): Models in Paleobiology. Freeman, Cooper, San Francisco
1972
Eccles, J. C.: Die Evolution des Gehirns – die Erschaffung 
des Selbst. Piper Verlag, München 1989
Popper, K. R., Eccles, J. C.: Das Ich und sein Gehirn. 
Piper Verlag, München 1982
Because of their isolation, these "aliens" had
an opportunity to develop and consolidate
their new characteristics with no competition.
Phenotype
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Evolution
29
nal intelligence, which enabled them to take
advantage of their opportunities. Their different
appearance caused them to be rejected by the horde
and possibly led to their expulsion. This was a
requirement for the establishment of an intelligent,
peripheral isolate capable of survival, and was a pre-
requisite for speciation. This contradicts Darwin's
thesis insofar that it was not the making and using
of tools that changed the morphology of the masti-
catory organ, but that the modified, "weaker" phe-
notype could only survive the selection mechanism
because it possessed sufficient creative desires to
make tools that would compensate for physical
deficiencies. The concurrent development of diffe-
rentiated communication, together with a more
capable masticatory organ and a suitable brain, was
a conditio sine qua non (see ill. 16 and 17, p. 30).
The freeing of hands through the attainment of an
upright posture was also an important contributory
factor.
This clearly shows that the process of hominizati-
on was an extremely active and formative one and
may be termed "creative" in the true sense of the
emergence of something new. Unsuccessful
attempts by hominids to continue their evolutio-
nary development by returning to physical attri-
butes, as was the case with Australopithecus ro-
bustus and boisei, underline the significance of
brain development secondary to communication.
The return to physicality was unsuccessful. These
branches of the hominid disappeared from the
world.
The development of abstract, communicative
speech necessarily led to the functional polarizati-
on of the brain and subsequently to that of the
eyes and ears (comp. Popper). The development of
two different brains, based on speech, is indirectly
connected to human "one-handedness". Thus,
sense-organ communication with the environ-
ment through the eyes and ears also became polar. 
... also provided with additional intelligence,
which enabled them to take advantage of their
opportunities. 
The concurrent development of differentiated
communication, together with a more capable
masticatory organ and a suitable brain, was a
conditio sine qua non.
The freeing of hands through the attainment
of an upright posture was also an important
contributory factor.
Sense-organ communication with the environ-
ment through the eyes and ears also became
polar. 
retrognathic
Speciation
Hominization
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R. Slavicek • The Masticatory Organ
30
Ill.. 16 (above): This
old illustration shows
the dramatic differ-
ences between the
dentition of primates
and the human mas-
ticatory organ.
Ill. 17 (left): The
reintegration of the
canine wasnot a
result of "substitut-
ing" the tooled
weapon for the bodi-
ly one, but a sign, at
the beginning of
hominid evolution, of
the different con-
struction of the visce-
rocranium. 
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The idiomatic expression "I've got an eye on you"
reflects the differential dominance in sensory per-
ception. Interestingly, the German equivalent of
"lend me your ears" is "lend me your ear". Thus,
the German idiom reflects differential dominance
while the English one fails to do so. The evalua-
tion of sensory impressions is also polar. Therefore,
in order to understand the human stomatognathic
system, it is especially important to investigate
the morphological readjustment of the organ and
the demands made on it by the complex function
of speech. Speech is inseparably linked to hearing.
The development of the transmitting mechanism
known as speech requires extreme morphological
differentiation of the masticatory organ, in order
that it be able to accomplish the entire spectrum
of the new function.
The so-called production of speech is of utmost
morphological interest. Comparisons of the
speech-producing apparatus of great apes or pri-
mates, especially chimpanzees, with that of
humans, reveal a continuous lowering of the
sound-producing apparatus. All studies carried
out indicate that the larynx of the chimpanzee is
sufficiently developed to bring forth speaking
sounds (comp. Tobias). The most important diffe-
rence appears to be that they do not possess the
cerebral qualifications or "readiness" that is nee-
ded to take advantage of this possibility. In con-
trast, the hominid apparently took advantage of
the opportunity at this time, under specific condi-
tions.
Oral communication in 
hominid evolution
Bühler formulates several levels for the concept of
speech, including "animal speech" and "human
speech". Bühler's scheme was expanded upon and
improved by Popper. Speech is an abstract means
of communication; it develops symbols and com-
binations of symbols that permit a "transmitter"
to communicate with a "receiver". Speech should
be regarded as a semiotic system. The Bühler-
Popper scheme is arranged in four functional
groups.
31
Evolution
Bühler, K.: Sprachtheorie: Die Darstellungsfunktion der
Sprache. Gustav Fischer, Jena 1934
Tobias, P. V.: Recent Advances in the Evolution of the
Hominids with Special Reference to Brain and Speech. In:
Chagas, C. (ed.): Recent Advances in the Evolution of
Primates. Pontificiae Academiae Scientiarum. Vatican City
Scripta Varia 50, S. 85–140, 1983
"I've got an eye on you" 
"Lend me your ears" 
The evaluation of sensory impressions is also
polar. 
Speech (Bühler/Popper)
Functions Values
Expressive function triggered / 
non-triggered 
Signaling function effectiveness / 
non-effectiveness
Descriptive function falsity / truth
Argumentative validity / non-validity
function
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Expression and Signaling
These two lower levels of communicative expres-
sion are already present in the animal world. Both
levels are utilized by the newborn human being
immediately after birth. However, viewing
human development from an ontogenetic view-
point, certain inferences regarding the evolutio-
nary development of speech may be made.
The two lower levels in the scheme are present in
the newborn. Here the function employed is the
expression of vowels that signify or express fee-
lings. The "conditioned" ear (usually the mother)
quickly learns to distinguish between hunger,
pain, comfort and anger. Initial communication
takes place and, when successfully employed and
confirmed by the receiver, triggers a characteristic
learning process.
The transition that leads to the formation of
abstract communication takes place through
intensive verbal imitation by the infant of what is
heard. Thus, hearing is an absolute prerequisite
for this process. Oral imitation contains the pri-
mary attempts to enrich expression by intersper-
sing the originally purely vowel expressions with
consonants. The "babbling" baby is actually a
learning and striving human being. Initially suc-
cessful communication, signaled by the doubling
of syllables, consists purely of soft tissue-suppor-
ted consonants, because of the absence of dentiti-
on. Repetition of syllables (e.g., "ma-ma", "pa-pa",
"da-da", etc.) is the first of this kind of communi-
cation, and the same throughout the world.
Primates, especially chimpanzees, have been
tested in intensive programs for their ability to
cross the threshold to abstract oral communicati-
on. In spite of these ongoing efforts, results show
no crossover to the third level of oral communica-
tion and there seems to be no readiness to "pass
on" the results of their hard labor.
Communication, Information
This limitation in the development of progressive
oral communication was no longer apparent in
hominids. Preparing areas of the brain and impro-
32
R. Slavicek • The Masticatory Organ
The two lower levels in the scheme are pre-
sent in the newborn. 
The transition that leads to the formation of
abstract communication takes place through
intensive verbal imitation by the infant of
what is heard. 
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ving "speech capabilities" in the masticatory organ
appear to have been prerequisites for the rapid
speciation of one or more small, "random" sub-
populations. Extensive sharing of information
made it possible to impart one's knowledge to
others. This development in oral communication
at the next higher level probably took place with
Homo habilus. This is indicated by a marked
increase in brain volume whereby, the increase in
frontal and dorsal speech centers is noteworthy.
Finally, the absolute breakthrough came about in
Homo erectus, who represented ultimate and suc-
cessful genetic progress. Humans rose and stood
erect. Brain volume and the regions of speech
were decidedly enlarged. This success is evidenced
by the rapid propagation of the species, along
with its high rate of reproduction.
The improved ability to reproduce had several
roots. One of these is the development of the so-
called "nuclear family", contingent on communi-
cation and characterized by social unity and
mutual solicitude. This behavior pattern already
existed in more highly developed animals, gover-
ned by instinct. Based on the difference in brain
development, altruistic components were mar-
kedly increased as hominization progressed. In
conjunction with the development of speech at a
higher level, progressive maturation into a social
being was one of the major steps towards homi-
nization.
Description
The development of descriptive, abstract speech is
most certainly the foremost step. The importance
of speech is recognized by religions of the world as
a central one. In the Bible, the creative force is
known as the Word. A superb quotation from
Tarouca underscores the importance of speech in
human relations.
From this point in time, the development of
speech as a means of "data transfer" of accrued
knowledge was the main impetus behind the
extremely rapid evolutionary process in anthropo-
genesis. The possibility of verbal expression cer-
tainly was a major contributor to the establish-
ment of social behavior and social structures. The
33
Evolution
In the beginning was the Word, and the
Word was with God, and the Word was God. 
The same was in the beginning with God. 
All things were made by him; and without
him was not any thing made that was made. 
In him was life; and the life was the light of
men.
(John 1, 1-4)
The "word" is the physical connection
between myself and others. (Tarouca)
… development of speech as a means of "data
transfer" of accrued knowledge …
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R. Slavicek • The Masticatory Organ
new levels of speech abilities extended far beyond
communication and expression, as they included
other novel possibilities: the ability to ask, under-
stand and answer questions, and the capability to
formulate a solidly based line of reasoning and its
individual interpretation. These created new and
truly incredible opportunitiesbetween the trans-
mitter and the receiver. The new levels include the
formulation of hypotheses and also, of course, the
possibility of the misleading lie.
Evolution of the psyche 
- the limbic system
Concurrent with the physical "difference" on the
road to becoming Homo, a remarkable mental
change occurred. In addition to important 
modifications in posture and communicative
capability, the "fall" of anthropogenesis led to
emotional imbalance. The originally polar balance
in the limbic system became increasingly imba-
lanced through hominization (see ill. 18, p. 35).
The limbic system may be briefly described as a
phylogenetically ancient functional system belon-
ging to the Archipallium. Topographically, it lies
between the brainstem and the neo-cortex. It con-
sists of the limbic cortex, a slightly layered gray
cortex, with the hippocampus, indusium griseum,
Gyrus cinguli and Gyrus parahippocampalis. Sub-
cortical areas of the Nucleus amygdalae and the
Area pyriformis and septalis, and the so-called
limbic middle-brain with median cell groups, are
also important.
The limbic system is closely associated with emo-
tion. Stimulation of its centers is liable to trigger
emotional reactions (positive and negative). A
simplified hypothesis of the limbic system separa-
tes it into two main components, which approxi-
mate pleasant and unpleasant emotions (comp.
McLean). These include fear and defensive reac-
tions as well as pleasant experiences such as hap-
piness, desire and sexual arousal.
In the course of evolution, a shift in emphasis in
favor of pleasant and enjoyable experiences occur-
MacLean, P. D.: Evolution of the Psychoencephalon.
Zygon 17, S. 187–211, 1982
34
The new levels include the formulation of
hypotheses and also, of course, the possibility
of the misleading lie.
The limbic system is closely associated with
emotion. 
Hypothesis
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Evolution
35
Ill. 18: The limbic system:
-topography between the brainstem and the neo-cortex,
-limbic cortex with the hippocampus, indusium griseum, Gyrus cinguli, Gyrus hippocampalis,
-sub-cortical area with the Nucleus amygdalae, Area pyriformi and septalis,
-limbic middle-brain with medial cell groups.
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red. The so-called pleasure centers of the limbic
system increased at a proportionally greater rate
than did the "aggressive" ones. The cortico-baso-
lateral (neo-cortical) areas now amounted to 81%
in humans, the centro-median (archeo-cortical)
areas to no more than 19%. This signifies a consi-
derable reduction in the components associated
with anger and aggression and greatly influences
the capability of aggressive behavior.
The "aggressive" centro-medial centers of the lim-
bic system did not continue to develop, probably
due to the enhancement of social (familial) beha-
vior patterns necessary for preservation of the spe-
cies. If you will; altruistic behavior was promoted
at the cost of egoistic principles. However, con-
trolled aggression is what keeps the individual
alive. It is a self-protective mechanism necessary
for self-preservation.
It follows that the evolution to human beings cau-
sed fundamental emotional changes. The altruistic
element, is the foundation of protective preservati-
on of the species, which developed disproportiona-
tely to the disadvantage of self-protective egoism,
allowing for and effecting the social structures of
communal living. Interestingly, altruism was evi-
dently subject to (territorial) limits. Modern human
behavior still demonstrates the ancient patterns of
pack and clan mentality.
The significant changes in the limbic system had
major consequences for the masticatory organ,
which could now be recruited as one of the poten-
tial organic levels for processing problems of a
psychological nature. Personal development was
permanently inhibited and the individual was for-
ced to "adjust", according to ethical, religious,
familial and legal rules of the social structure.
According to these rules, the free development of
self-preserving egoism was inhibited and conside-
red "sinful". Direct, immediate problem solving
became ever more difficult, or impossible. The
relationship between the psyche and the mastica-
tory organ must now be analyzed, from the view-
point of subconscious problem solving, at the
organic level. Life is a constant challenge and the-
refore creates constant stress. From the viewpoint
of maintaining adaptation, this inherent stress is
required as a perpetual stimulant for all vital pro-
cesses. Stress is countered by a positive aggressive
reaction from the organism for the purpose of sur-
vival (note here the absurd negative connotation
36
R. Slavicek • The Masticatory Organ
Controlled aggression is what keeps the indi-
vidual alive. It is a self-protective mechanism
necessary for self-preservation.
Modern human behavior still demonstrates
the ancient patterns of pack and clan mental-
ity.
The relationship between the psyche and the
masticatory organ must now be analyzed,
from the viewpoint of subconscious problem
solving, at the organic level. 
Aggression
Egoism
Altruism
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of the word "aggression" in current jargon). Life is
a constant struggle to come to terms with exter-
nal and internal problems; but "coming to terms"
means resolving and/or eliminating the problem.
The relationship between the psyche and soma, in
the context of the problem of the mind and the
brain, plays a central role in human evolution.
Following the emergence of consciousness, the
emergence of self-consciousness, which is unique
to humans, became very important. The new self-
consciousness includes the realization of death,
with all its spiritual possibilities, and the question
of confronting the cessation of one's own existen-
ce. This awareness is already evidenced, to a great
extent, in the demise of the Neanderthal culture,
Homo sapiens neanderthalis.
A definite shift in the emotional-aggressive beha-
vioral pattern may be seen in pongids, above all,
in the highly developed chimpanzee, the most clo-
sely anthropoid of all the apes. The only chim-
panzees with the option to eat meat are by no
means predatory, and are not equipped for the
role. Nevertheless, at intervals they display an
aggressive urge to hunt. They will either fulfill
this need at the expense of gibbons, with whom
they usually live in peaceful co-existence, or (what
an ominous sign for the future!) they hunt other
bands of chimpanzees. During these intervals, the
altered emotional behavior of the pack is conspi-
cuous, especially that of male adolescents, the
"young toughs" of the pack who are the initiators.
Their unprofessional killing is in contrast to true
predatory behavior and is often interrupted by
absurd mental behavior, such as sympathetic
actions towards the victim. Vogel correctly 
describes this behavior as the crossover point from
killing to murder.
A further change in emotional behavior concerns
sexual activity and reproduction. The polarization
in the limbic system and its "promotion" of plea-
sure centers, the upright posture of the body, and
the concomitant "overt presentation of erogenous
zones", are altered in Homo's sexual behavior
compared to that of hominids.
37
Evolution
Vogel, Ch.: Vom Töten zum Mord. Carl Hanser Verlag,
München, Wien 1989
... but "coming to terms" means resolving
and/or eliminating the problem.
The new self-consciousness includes the real-
ization of death, 
The only optionally meat-eating chimpanzees
are by no means predatory and are not
equipped for the role. 
The "young toughs" of the pack who are the
initiators. 
Vogel correctly describes this behavior as the
crossover point from killing to murder.
Emotion
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Effects of evolution - 
an overall view
In summary, the evolutionary effects of human
brain development may be listed as follows:
- the development of communicative 
speech
- the development of functional asymme-
try in the brain
- the expansion of consciousness and the 
emergence of self-consciousness