THE CONCEPTS OF
KINETIC OF
OROFACIAL MUSCLES
IN COMPLETE
DENTURE
PROSTHODONTICS
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INTRODUCTION
“Nothing is more fundamental to
treating patient than knowing the
anatomy” – Jeffrey.P.Okeson23

www.indiande...
(We) prosthodontist treat patients with artificial
substitutes that restore the natural teeth and/or
replace missing teeth...
Out of the aforementioned requirements,
No. 5 is a challenge to the prosthodontist.
To meet these requirements and
challen...
“Muscles are of primary interest because it
performs mechanical works” 24.
The
kinematics and relative movements of
orofac...
The muscles of facial expression,
muscles of the tongue, the suprahyoid
muscles, the muscles of soft palate and
pharyngeal...
The aim of this seminar is to understand the
kinematics and relative motions of the
orofacial musculature.
Within the cont...
SOME TERMINOLOGIES
Kinetic – pertaining to or producing motion3 /
relating to and resulting from motion28
Kinetics – The s...
Fascia (FASH – e a, fascia = bandage)- the
term applied to a sheet or broadband of
fibrous connective tissues underneath t...
Isotonic contraction – As the contraction
occurs, the muscle shortens and pulls
on another structure such as bone to
produ...
MUSCLES
OF
OROFACIAL
COMPLEX
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The muscles of the orofacial complex
are of skeletal and striated type and
voluntary in nature.. The skeletal
muscles of t...
GROWTH AND DEVELOPMENT

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The muscles of the mouth
and related structures are
derived from the mesoderm
of the branchial arches .
About the sixth se...
The muscles of facial expressions are derived
from the second or hyoid arch, innervated by the
Facial (VIIth cranial) nerv...
AGING AND MUSCLE TISSUE
Beginning at about 30
years of age, a
progressive loss of
skeletal muscle mass
that is largely rep...
KINETIC OF OROFACIAL MUSCLES
“Fundamentally, any functional movement is a result of
muscular contraction.”14
Facial moveme...
The movements of the
skeletal parts can be
explained using the
lever system :
Class I
Class II
Class III
Movement occurs t...
Prime movers are actually responsible
for the movement, whereas
antagonists are those muscles, which
produce opposing move...
Fixation muscles establish a stable basis
by steadying a structure. For example the
infrahyoid muscles steady the hyoid bo...
ANATOMY IN ACTION - INTERPLAY
OF MUSCLE AND BONE
For any facial movements, there
must be a frame; that frame is
the skull....
The two condyles of the mandible articulate with
the cranium in the mandibular fossae of the
temporal bones. These articul...
The pyramidal area14-16 housing these two movable
bones, their articulators, and the muscle
attachments is of extreme sign...
MOVEMENTS OF FACIAL EXPRESSION

Studies of the evolution of facial
expression in man indicate that there is
practically no...
THE FACIAL MUSCLES OF EXPRESSION
Muscle

Origin

Insertion

Action

Innervation

Galea
aponeuroti
ca

Skin
superior
to
sup...
Zygomaticus
major
Zygomatic =
cheek bone;
major =
greater

Zygomatic bone

Levator labii
superioris
(levator = raises
or e...
Mentalis
(mentum = chin)

Mandible

Platysma
(platy = flat,
broad)

Fascia over
deltoid and
pectoralis
major
muscles.

Ris...
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These muscles are further characterized
by the insertion of delicate fiber and
tendon attachments into the skin and
mucosa...
By repeated contraction of the
muscles that are inserted directly
into the cutis. Wrinkles develop into
grooves or dimples...
For the purposes of description the
muscles of facial expression may be
divided into the following groups:
(1) the muscles...
Muscles of the forehead: the frontalis is a large, flat
quadrilateral muscle having no bony attachment. It
originates from...
Muscles of the eyelids and eyebrows: The
orbicularis oculi surrounds the eye, and its
contraction closes the eyelid, pulls...
MUSCLES THAT MOVE THE EYEBALLS EXTRINSIC MUSCLES
Muscles

Origin

Insertion

Action

Innervations

Superior rectus
(superi...
Superior oblique
(oblique = in this
case, muscle fibers
running diagonally
to long axis of eye
ball

Same as above

Eyebal...
The corrugators is the chief muscle
controlling the movements of the eyebrow.
A supercilious look of an individual is the
...
MUSCLES OF THE NOSE REGION:
The four muscles of the nose
are very delicate and feeble.
They are the procerus,
nasalis, dil...
The nasalis muscle draws the
wing of the nose toward the
septum. The nares of the
nose are compressed by this
action, and ...
MOVEMENTS OF LIPS AND CHEEKS MUSCLES
Emotion of joy – Joy or happiness may be reflected in
individuals in varying degrees,...
Smile – “Physically and psychologically a
smile enhances ones outward appearance
and tend to improve self-confidence and
f...
In smiling, there is contraction of the
zygomaticus major (antagonist:
orbicualris oris), which draws the
modiolus, and th...
The fibers of the orbicularis oris muscle
occupy the entire width of the lips. They
extend from the angles of the mouth an...
The arrangement
and movement of the
fibers are similar in
both lips.The
convergence of the
fibers at the angle of
the mout...
A smile may terminate with the face returning to a
state of repose and the modiolus assuming its
neutral position. This te...
Laughing: The smile, instead of terminating,
many progress to accelerated proportions in
the activity of laughter, which i...
The distance between the nasal septum
and the red marking of the maxillary lip is
very much decreased, and the nasolabial
...
Emotion of distress – In distress, the mouth is firmly closed.
The rima oris is reduced in size to a narrow, cranially bow...
MOVEMENTS OF TONGUE MUSCLES

One of the most versatile and complex of
the structures of the stomatognathic
system is the t...
Muscles

Origin

Insertion

Genioglossus
Geneion = chin;
glossus =
tongue

Mandible

Styloglossus
(stylo = stake or
pole; ...
The root of the tongue is attached to the soft palate, pharynx,
hyoid bone, and epiglottis, while the tip, sides, and dors...
During the process of mastication, the tongue
serves as a greeter, a moistener, a shock
absorber, a bracer, a guide, a tas...
The great adaptability of the tongue is
apparent when teeth are lost and when
missing teeth are replaced . With the loss
o...
It should be noted that the tongue assumes various positions.
Although combine action of extrinsic muscle are related to t...
MUSCLES THAT MOVE THE MANDIBLE,
FLOOR OF THE MOUTH AND THE HEAD
The muscle of mastication in association with
inframandibu...
MUSCLES OF MASTICATION
Four pairs of muscles make up a group called
the muscles of mastication:
(1) Masseter, (2) temporal...
MASSETER
The masseter is a rectangular muscle that originates from
the zygomatic arch and extends downward to the lateral
...
As fibers of the masseter contract, the mandible is
elevated and the teeth are brought into contact.
The masseter is a pow...
TEMPORALIS
The temporalis is a large, fan
shaped muscle that originates from
the temporal fossa and the lateral
surface of...
The anterior portion consists of fibers that are
directed almost vertically
The middle portion contains fibers that run
ob...
When the temporal muscle contracts it elevates the
mandible and the teeth are brought into contact. If
only portions contr...
DuBrul25 suggest that the fibres below the
root of the zugomatic process are the only
significant one; therefore contracti...
MEDIAL PTERYGOID
The medial (internal)
pterygoid originates from the
pterygoid fossa and extends
downward, backward, and
o...
LATERAL PTERYGOID
The lateral pterygoid is divided and identified
as two distinct and different muscles, which
is appropri...
Inferior lateral pterygoid: The inferior lateral pterygoid originates
at the outer surface of the lateral pterygoid plate ...
SUPERIOR LATERAL PTERYGOID
The superior lateral pterygoid is considerable smaller than the
inferior and originates at the ...
Although the inferior lateral pterygoid is
active during opening the superior
remains inactive becoming active only in
con...
It is to note that the pull of the lateral pterygoids
on the disc and condyle is in a significantly
medial direction. As t...
It is essential for a prosthodontist to be fully
aware not only of the basic mandibular
movements and positions but also o...
MUSCLES OF THE FLOOR OF THE ORAL CAVITY

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SUPRAHYOID & INFRAHYOID MUSCLES
These muscles suspend the hyoid bone, lower the mandible,
and have prosthodontic significa...
These are voluntary muscles but act reflexively
and, during mandibular rest position, are in
balance with the supramandibu...
The vertical tug of war which takes
place in the opening and closing
movements of the mandible is
produced by the elevator...
MUSCLES THAT MOVE THE HEAD

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Mandibular movements are limited and modified
by the temporomandibular articulations
posteriorly and the teeth anteriorly....
POSTERIOR CERVICAL MUSCLES
The head rests upon the atlas,
the uppermost vertebra of the
spinal column, in positional
unbal...
The structures responsible for
maintaining the head in balance are
the posterior cervical muscles
working antagonistically...
MUSCLES THAT MOVES THE SOFT PALATE
Muscles

Origin

Levator veli palatani
Levetor = rouses
Velum = veil
Palato -palat

Pet...
Musculature of the soft palate is divided into two functional
groups, the depressors and elevators. The depressors are
ext...
The tensor veli palatini, as the name implies,
flattens tenses, and lowers the soft palate and at
the same time opens the ...
Based on the degree of flexure the soft palate makes
with the hard palate and the width of the palatal seal
area, soft pal...
The kinetic
of the soft
palate in
coordination
with tongue
muscle and
muscle of
pharynx
and larynx
play a major
role durin...
MUSCLES OF PHARYNX
Muscles
Circular layer
Inferior
constrictor
(inferior = below;
constrictor =
decreases
diameter of a
lu...
Longitudinal
layer
Stylopharyngeus
(stylo = stake or
pole; styloid
process of
temporal
bone;
pharyngo =
pharynx )

Salipin...
MUSCLES OF LARYNX
Muscles

Origin

Insertion

Action

Extrinsic
Omohyoid
(omo = relationship
to the
shoulder;
byoedes = Us...
Anterior and lateral
portion of cricoid
cartilage of larynx

Anterior border of
inferior cornu of
thyroid cartilage of
lar...
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The process of eating can be divided into
(1) premasticatory (2) masticatory
(3) swallowing activities associated with the...
SWALLOWING (DEGLUTITION)
Swallowing is a series of coordinated muscular
contractions that moves a bolus of food from the
o...
Although swallowing is one continuous act, for purposes
of discussion it is divided into three stages. 23
First Stage: The...
Second stage: Once the bolus has reached the pharynx a
peristaltic wave caused by contraction of the pharyngeal
constricto...
Third stage: the third stage of swallowing consists of
passing the bolus through the length of the esophagus and
into the ...
CLINICAL APPLICATIONS OF CONCEPT OF
KINETIC
The diagnostic phase:
Diagnosis begins when the Prosthodontist first
views his...
Some of the external evidences of
loss of supporting structures are
sunken cheeks, flattened lips,
decrease in the width o...
However, lack of support may not
always be the entire cause of some
of the sings and symptoms apparent
in surface anatomy....
This will affect the
prosthodontic treatment
because any attempt to
provide support artificially
where there has been no
l...
External evidences of temperament and
tension – In general, the direction of the lines of
the face can be taken as indicat...
Observation of these facial markings in the
initial diagnosis provides a clue to the
temperament of the patient and sugges...
OTHER INDICATION FROM
SURFACE ANATOMY
This involves the muscle attachments within the oral
cavity, the strength and amount...
Any asymmetry of the eyes observed in diagnosis should
be noted so that necessary allowances can be made
when the pupils o...
The speech and facial expressions of the patient
may be studied during the initial interview. An
analysis of these functio...
SPEECH AND PATIENT
CLASSIFICATION
Speech sometimes serves as an aid in the initial
classification of the patient 18. Rapid...
SPEECH DEFECTS
Many persons are not aware that they have
speech defects. Preoperative speech
recordings during the prelimi...
A patient who has lost most of the teeth and has
never had them replaced reflects speech
modifications. During the period ...
EFFECTS OF LOSS OF TEETH ON OTHER SPEECH
ARTICULATORS

The loss of posterior teeth results in
spreading of the tongue. The...
DEFECTS IN PRONUNCIATION OF
CERTAIN CONSONANTS
Even under ideal conditions, i.e. when a speaker
has a full complement of n...
Defects in the pronunciation of the
consonants f and v are most often caused
by the inability of the mandibular lip to
con...
Defects in the pronunciaton of the
consonants t and d are often due to
placement of the maxillary anterior teeth
too far p...
FACIAL EXPRESSION
There are many reasons for including
facial expression in the functional analysis
of the patient. Moveme...
SIGNIFICANT FACIAL MOVEMENT

Certain types of facial movements have
particular significance in treatment
planning.
Exagger...
HABITUAL FACIAL EXPRESSION
“Masticatory muscle hyperactivity is thought to
produce muscle pain and tension headaches and
c...
DIAGNOSTIC EVALUATION OF THE
EDENTULOUS MOUTH

Three acts are performed almost
simultaneously in the examination of an
ede...
The amount of space between the residual
alveolar ridge and the lips during functional
activities must be considered in re...
MODIOLUS
In an edentulous mouth, the modioli assume a sagging
position, become less active, diminish in size, and change i...
The mandibular denture should be visualized in relation to
the allowance necessary to accommodate for this muscle
mass. Th...
The tongue is a powerful and extremely
adaptable organ. Observation of the
position of the tongue should be made with
the ...
During swallowing, the teeth serve as
limiting boundaries to the inward
movements of the cheeks and lips and to
the upward...
This space is difficult to located because of (1)
the changes in the alveolar ridge, (2) the
approximation of the tongue a...
The structures under the tongue are of
concern particularly when they are in an
abnormal functional relationship to the
ma...
As the residual alveolar
ridge becomes smaller,
these sublingual
structures become
more dominant in their
functional relat...
CLINICAL APPLICATION OF
CONCEPTS OF KINETIC
The recording phase:
The recording phases can be considered as a
continuous di...
IMPRESSION
The impression procedures must adhere to the
following biological principles (Boucher C.O) 5
dictated by the an...
3.A physiologic type of border-moulding procedure
is performed by the prosthodontist or by the
patient under the guidance ...
7.A guiding mechanism is provided for
correct positioning of the impression tray
in the mouth.
8.The tray and final impres...
PRIMARY IMPRESSION
When a primary impression is made for
preparation of a custom tray for final
impressions, the objective...
The maxillary impression should include
the hamular notches, fovea palatina,
entire buccal vestibule, including the
aforem...
All the functional movement of the lips,
cheeks and the tongue should be
recorded by allowing the patient to do the
same m...
BORDER MOULDING AND FINAL IMPRESSION

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Schematic presentation of border moulding
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Schematic presentation of border moulding
The border moulded final impression
tray should be so formed that it
supports the cheeks and lips in the
same manner as th...
It should be possible for the patient to wipe with
the tip of the tongue across the vermilion border
of the upper lip with...
RECORDING OF MAXILLOMANDIBULAR RELATION

Provisional vertical dimension of physiologic rest
position
In recording maxillom...
SWALLOWING
The act of swallowing is used initially because it
provides a more natural action to determine the
height of th...
Phonetics: certain
speech sounds may serve
as an aid in recording
physiologic rest position.
Speech containing ‘m’
sounds ...
Vertical dimension of occlusion
Provisional vertical dimension of occlusion can be
obtained using speech activities simila...
CLINICAL APPLICATION OF
CONCEPTS OF KINETIC
The final phases of denture
construction
Although certain esthetic factors may...
LIP SUPPORT
Adequate lip support involves more than a
concern for esthetics physiologically, the
functions of speech, faci...
The framework of musculature chiefly
responsible for the contours and
movements of the lips is the orbicularis
oris which ...
In considering problems of lip support,
more attention is generally accorded to
the maxillary lip than to the mandibular l...
The mandibular lip, bounded laterally by the
labiomarginal sulci, the rima oris above, and the
mentolabial sulcus below, i...
GUIDELINES FOR DEVELOPING
ADEQUATE LIP SUPPORT
1.The following guides may be used in establishing
adequate lip support.
2....
4.The labial surfaces of the teeth should be 8 to 10
mm. in front of incisive papilla and should be out
as far or in front...
8.The length of the maxillary anterior teeth and the
amount which shows below the lip should be
checked by having the pati...
SURFACE ANATOMY INDICATIONS OF THE
AMOUNT OF LIP SUPPORT
External evidences which assist in critically
evaluating the amou...
Indications of too much support
include: tensed, stretched
appearance of the lips which
can result in tension lines
around...
Maxillomandibular relation records are
verified by observing the phase in repose and in
function.
The amount of support is...
If the vertical dimension of occlusion is
decreased, there will be inadequate
tongue space. This condition will cause
freq...
THE POLISHED SURFACES
All three surfaces of the dentures i.e., the impression,
the occlusal and the polished surfaces, sho...
The Mandibular Denture:
The mandibular denture is generally more difficult than
maxillary for the Prosthodontist to constr...
By properly designing the inclined planes of the
denture flanges, and by not placing the lingual
surfaces of the teeth lin...
The labial flanges are determined by the position of
the mandibular incisors, which must be in the same
place the natural ...
The lingual surfaces of the lingual flange
should face inward and upward so that the
borders lie under the tongue. Thus, t...
The maxillary denture: The buccals surfaces should face
outward and downward and should fill the buccal vestibules.
The bu...
Review of literature
Mark A. Pigno and Jeff. J. Funk 12 – Prosthetic
management of a total glossetomy defect after free fl...
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David Marmor and James E. Herbertson,2 the use of
swallowing in making complete denture J. Pros Den Vol 19;3:
208-18 March...
These fibers, suspended from the inner surface of the
mandible on both sides, form a sling to raise the tonguehyoid-larynx...
Simmonds Charles R. and Philip M. Jones26
A variation in complete mandibular impression form
related to an anomaly of the ...
They concluded that the mylohyoid eminentiae occurs
when a gap exists in the mylohyoid muscle. During
impression making, u...
John L. Shannon10 edentulous impression
procedure for region of the mentalis muscles –
Vol 26; 2:130-33,1971
He described ...
PROCEDURES
1. When the mentalis muscles are clinically evident by palpation or
sight
2. A black modeling compound tray is ...
Harold W. Preiskel 8 The posterior lingual extension of complete
lower dentures. J. Pros Den, Vol 19, 5: 452-59, May, 1968...
Lawson W.A. 11 Influence of the sublingual fold on
retention of complete lower denture, J. Pros Den Vol
11; 6: 1038-44 (No...
Thus, the seal is developed by the floor of the mouth when
the tongue tip is retracted and by the sublingual fold when
the...
Barred et al 1 – structure of the mouth in the mandibular
molar region and its relation to denture J. Pros Den Vol
12, 5: ...
The yielding triangle allows a
retromylohyoid extension of the denture
and the pad and the construction of a
small post dm...
Wilkinson T. M. 30 – the relationship between the disck and
lateral pterygoid muscle in the human temporomandibular
joint ...
SUMMARY
When the kinetics of the
orofacial muscles and
those associated
structure are better
understood, the borders
of th...
REFERENCES
1. Barred et al – structure of the mouth in the mandibular molar region
and its relation to denture J. Pros Den...
•
•
•
•
•

•

•

John L. Shannon – edentulous impression procedure for region of
the mentalis muscles – Vol 26; 2:130-33,1...
•

•

•

•

•
•
•
•

Martone A. L. et al- The phenomenon of function in complete denture
prosthodontics; Anatomy of the mo...
• Sicher and Dr Brul’s Oral anatomy – 8th ed. 1988
• Simmonds Charles R. and Philip M. Jones – A variation
in complete man...
THANK YOU
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Kinetics of orofacial muscles in complete dentures /certified fixed orthodontic courses by Indian dental academy

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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

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Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078



The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.


Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
00919248678078

Kinetics of orofacial muscles in complete dentures /certified fixed orthodontic courses by Indian dental academy

  1. 1. THE CONCEPTS OF KINETIC OF OROFACIAL MUSCLES IN COMPLETE DENTURE PROSTHODONTICS www.indiandentalacademy.com
  2. 2. INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  3. 3. INTRODUCTION “Nothing is more fundamental to treating patient than knowing the anatomy” – Jeffrey.P.Okeson23 www.indiandentalacademy.com
  4. 4. (We) prosthodontist treat patients with artificial substitutes that restore the natural teeth and/or replace missing teeth and craniofacial tissues. So, we are responsible to introduce life in the artificial substitutes (prosthesis). A prosthesis can be called as a successful prosthetic therapy when it can fulfill the following the requirements. 1. Compatibility with the surrounding oral environments. 2. Restoration of masticatory efficiency within limits 3. Ability to function in harmony during mastication, speech respiration and deglutition. 4. Esthetics acceptability 5. Prevention of that which remain www.indiandentalacademy.com
  5. 5. Out of the aforementioned requirements, No. 5 is a challenge to the prosthodontist. To meet these requirements and challenge the prosthodontist must have proper knowledge of the basic anatomy and physiology of the orofacial structure and sound understanding of biophysics and biomechanics of the supporting structures of the prosthesis. www.indiandentalacademy.com
  6. 6. “Muscles are of primary interest because it performs mechanical works” 24. The kinematics and relative movements of orofacial muscles are responsible for facial expression in projecting the personality and characteristic of the individual. Muscles that produce movement of the mandible, hyoid bone, the tongue, lips, cheeks, soft palate, oro-pharynx, in turn help in mastication, speech, respiration and deglutition. These muscles are also responsible to keep the mandible in rest position and maintain health www.indiandentalacademy.com and comfort of the stomatognathic system
  7. 7. The muscles of facial expression, muscles of the tongue, the suprahyoid muscles, the muscles of soft palate and pharyngeal muscles are primarily involved in determining the extent of the border and contour of the polished basal seat of the removable prosthesis and also in positioning of the teeth. Therefore, the proper handing of these muscles during any prosthodontic procedure is an essential act to make use of the muscular movement to serve the purposes of the prosthesis. www.indiandentalacademy.com
  8. 8. The aim of this seminar is to understand the kinematics and relative motions of the orofacial musculature. Within the context of the seminar, I will discuss the kinetic of orofacial muscles and analyze their relevant prosthodontic significance with emphasis in relation to removable complete denture therapy; since the retention, stability, support and esthetics of this type of prosthesis are mainly facilitated by the underlying hard and associated soft tissues www.indiandentalacademy.com
  9. 9. SOME TERMINOLOGIES Kinetic – pertaining to or producing motion3 / relating to and resulting from motion28 Kinetics – The scientific study of the turnover or rate of change or specific factor in the body, commonly expressed as units of amount per unit time. 3 Chemical kinetics3 – the study of the rates and mechanism of chemical reactions Kinematics- The phase of mechanics that deals with possible motion of a material body (GPT)27 Kinesilogy attempts to explain the manner in which movement of the body occur by considering collective areas of information from anatomy, physics and mechanics” 29 www.indiandentalacademy.com
  10. 10. Fascia (FASH – e a, fascia = bandage)- the term applied to a sheet or broadband of fibrous connective tissues underneath the skin or around muscles and organs of the body. Fasciculi – bundle of muscle Tendon and aponeuroses - extension of connective tissue beyond muscle cells that attach the muscle to bone or other muscle Ligaments - dense, regularly arranged connective tissues that attach bone to bone www.indiandentalacademy.com
  11. 11. Isotonic contraction – As the contraction occurs, the muscle shortens and pulls on another structure such as bone to produce movement. During such contraction, the tension remains constant and energy is expended. Isometric contraction: Muscle length does not shortens but the tension greatly increases. This type of contraction does not produce any movement. www.indiandentalacademy.com
  12. 12. MUSCLES OF OROFACIAL COMPLEX www.indiandentalacademy.com
  13. 13. The muscles of the orofacial complex are of skeletal and striated type and voluntary in nature.. The skeletal muscles of this regions are responsible for different functional and non functional movements. Muscle fibers are mixture of type I (slow) and type II (fast) fibers in varying proportions that reflect the function of that muscles. The slow muscle fibers have a welldeveloped aerobic metabolism and are therefore resistance to fatigue. The fast muscle fibers are capable of quick contraction but fatigue more rapidly. www.indiandentalacademy.com
  14. 14. GROWTH AND DEVELOPMENT www.indiandentalacademy.com
  15. 15. www.indiandentalacademy.com
  16. 16. The muscles of the mouth and related structures are derived from the mesoderm of the branchial arches . About the sixth seek of embryonal life, the muscles of these arches, which are innervated by certain cranial nerves, undergo modification and migration but retain their original cranial nerve supply. The muscles of mastication, the tensor veli palatini tensor tympani, anterior belly of the digastric, and mylohyoid, are derived from the first branchial arch and are supplied by the mandibular brach of the trigeminal (Vth cranial) nerve. www.indiandentalacademy.com
  17. 17. The muscles of facial expressions are derived from the second or hyoid arch, innervated by the Facial (VIIth cranial) nerve From the third and fourth arches, develop the pharyngeal, laryngeal, and the other palatal muscles, which are supplied by the Glossopharyngeal (IXth), Vagus (Xth cranial) and the cranial portion of the Spinal Accessory (XIth cranial) nerves. The muscles of the tongue(hypoglossal cord) and extrinsic muscles of eyes however, are derived from the condensed somites those are formed from the myoblast cells located close to the neural plate. The tongue muscles are supplied by the Hypoglossal (XIIth cranial) nerve. www.indiandentalacademy.com
  18. 18. AGING AND MUSCLE TISSUE Beginning at about 30 years of age, a progressive loss of skeletal muscle mass that is largely replaced by fat. Accompanying the loss of muscle mass, there is a decrease in maximal strength and a diminishing of muscle www.indiandentalacademy.com reflexes.
  19. 19. KINETIC OF OROFACIAL MUSCLES “Fundamentally, any functional movement is a result of muscular contraction.”14 Facial movements – facial movements are the result of the automatic coordinated effort of many muscles in different functional capacities executed in the cerebral cortex. www.indiandentalacademy.com SENSORY CORTEX MOTOR CORTEX
  20. 20. The movements of the skeletal parts can be explained using the lever system : Class I Class II Class III Movement occurs through paired muscular activity. In order for a muscle to contract, its opponents must relax. Individual muscles may function by being (1) prime movers (2) antagonists, (3) fixators, or (4) www.indiandentalacademy.com synergists.
  21. 21. Prime movers are actually responsible for the movement, whereas antagonists are those muscles, which produce opposing movements. Thus in closing the mouth, the inframandibular muscles relax and the three closing muscles of mastication contract ; in opening of the mouth the reverse action takes place www.indiandentalacademy.com
  22. 22. Fixation muscles establish a stable basis by steadying a structure. For example the infrahyoid muscles steady the hyoid bone so that the suprahyoid muscles may contract lowering the mandible. A synergist ( “to work together” )muscle aids the prime mover in it’s action. For example, the internal pterygoid muscle is a synergist of masseter muscle in that it helps it to elevate the mandible. www.indiandentalacademy.com
  23. 23. ANATOMY IN ACTION - INTERPLAY OF MUSCLE AND BONE For any facial movements, there must be a frame; that frame is the skull. In the anatomic region concerned with these movements, there exist a fixed bone region and a movable bone region. The two points of anchorage are the anterior part of the cranium and the sternum, and between are synergistic groups of muscles that move the skin and bone to alter expression. Between these anchors, the mandible and the hyoid bone are suspended. www.indiandentalacademy.com
  24. 24. The two condyles of the mandible articulate with the cranium in the mandibular fossae of the temporal bones. These articulations provide certain leverage advantages as well as control and limitation of mandibular movement. Further limitation is placed on the movements of the mandible by the teeth and by muscle attachments. The hyoid bone, smaller than the mandible but of a similar shape, is situated in front of the throat at the root of the tongue. It is called the tongue bone because it supports the tongue and serves as an origin of attachment for some of its muscles. It is not articulated with any other bone. Its movements are dependent upon muscular activity. www.indiandentalacademy.com
  25. 25. The pyramidal area14-16 housing these two movable bones, their articulators, and the muscle attachments is of extreme significance because of the multiple functions, which take, place in whole or in part therein. Some of these functions are of a vegetative nature, common to all animals, such as breathing, mastication, and deglutition, while others, equally highly specialized, are characteristic of man, such as speech and facial expression. www.indiandentalacademy.com
  26. 26. MOVEMENTS OF FACIAL EXPRESSION Studies of the evolution of facial expression in man indicate that there is practically no facial expression in the newborn infant. It becomes manifold and definite as the infant’s conscious and intelligent reactions to the surrounding world increase.14 www.indiandentalacademy.com
  27. 27. THE FACIAL MUSCLES OF EXPRESSION Muscle Origin Insertion Action Innervation Galea aponeuroti ca Skin superior to supraorbit al line Draws scalp forward, raises eye brows, and wrinkles skin of forehead horizontally Facial (VII) nerve Occipitalis (occipito = base of skull) Occipital bone and mastoid process of temporal bone Galea aponeurot ica Draws scalp backward (Facial (VII) nerve Orbicularis oris (Orb = circular; or= mouth Closes lips, compresses Muscle fibers lips against surroundin Skin at corner teeth, protrudes g opening of mouth lips, and shapes of mouth lips during www.indiandentalacademy.com speech. Frontalis (Front = forehead) Facial (VII) nerve
  28. 28. Zygomaticus major Zygomatic = cheek bone; major = greater Zygomatic bone Levator labii superioris (levator = raises or elevates; labii = lip; superioris = upper) Superior to infraorbital foramen of maxilla Depressor labii inferioris (depressor = depresses or lowers; inferioris = lower Buccinator (bucc = cheek) Mandible Skin at angle of mouth and orbicularis oris Draws angle of mouth upward and outward as in smiling o laughing Facial (VII) nerve Skin at angle of mouth and orbilaris oris Elevates (raises) up per lip Facial (VII) nerve Skin of lower lip Depresses (lowers) lower lip Facial (VII) nerve Alveolar processes Major cheek muscle; of maxilla and compresses cheek mandible and as in blowing air out pterygomandibu of mouth and lar raphe Orbicularis oris (fibrous band causes cheeks to extending from cave in, producing the pterygoid the action of hamulus to the sucking mandible) www.indiandentalacademy.com Facial (VII) nerve
  29. 29. Mentalis (mentum = chin) Mandible Platysma (platy = flat, broad) Fascia over deltoid and pectoralis major muscles. Risorius (risor = laughter) Fascia over parotid (salivary)glan d Orbicularis oculi (Ocul = eye) Corrugator supercilli (corrugo = wrinkle; supercilium = eyebrow) Levator palpebrae superioris (palpebrae = eyelids) Medial wall or orbit Medial end of superciliary arch of frontal bone. Skin of chin Mandible muscles around angle of mouth and skin of lower face Skin at angle of mouth Circular path around orbit Skin of eyebrow Elevates and protrudes lower lip and pulls skin of chin up as in pouting Facial (VII) nerve Draws outer part of lower lip downward and backward as in pouting; depresses mandible Facial (VII) nerve Draws angle of mouth laterally as in tenseness Facial (VII) nerve Closes eye Facial (VII) nerve Draws eyebrow downward as in frowning Roof of orbit (lesser wing Skin of upper Elevates upper eye lid of sphenoid eyelid bone) www.indiandentalacademy.com Facial (VII) nerve Oculomotor (III) nerve.
  30. 30. www.indiandentalacademy.com
  31. 31. These muscles are further characterized by the insertion of delicate fiber and tendon attachments into the skin and mucosa of the lips and by their rich innervations and blood supply. These muscles are directly subjacent to the freely movable skin. When they contract, the elastic skin is folded at right angles to the direction of the pull of the muscles. www.indiandentalacademy.com
  32. 32. By repeated contraction of the muscles that are inserted directly into the cutis. Wrinkles develop into grooves or dimples. These grooves become deeper with advancing age because of the loose of elasticity of the skin. www.indiandentalacademy.com
  33. 33. For the purposes of description the muscles of facial expression may be divided into the following groups: (1) the muscles of the forehead, (2) the muscles of the eyelids and eyebrows, (3) the muscles of the nose, and (4) the muscles of the lips and cheeks. www.indiandentalacademy.com
  34. 34. Muscles of the forehead: the frontalis is a large, flat quadrilateral muscle having no bony attachment. It originates from the galea aponeurotica of the scalp and is inserted into the skin under the eyebrows and the skin over the root of the nose. Its broad fibers blend in with other muscle fibers in the orbital region. The contraction of this muscle is responsible for the transverse line of the forehead and the raising of the eyebrows, giving an expression of surprise, amazement, or fear. www.indiandentalacademy.com
  35. 35. Muscles of the eyelids and eyebrows: The orbicularis oculi surrounds the eye, and its contraction closes the eyelid, pulls down the eyebrow, and raises the cheek. The latter two actions are responsible for the “cow feet” wrinkles in the corner of the eye. www.indiandentalacademy.com
  36. 36. MUSCLES THAT MOVE THE EYEBALLS EXTRINSIC MUSCLES Muscles Origin Insertion Action Innervations Superior rectus (superior = above; rectus = in this case, muscle fibers running parallel to long axis of eyeball) Tendinous ring attached to bony or bit around optic foramen Superior and central part of eyeball Rolls eyeball upward Oculomotor(III) nerve Inferior rectus (inferior = below) Same as above Inferior and central part of eye ball Rolls eyeball downward Oculomotor (III) Lateral rectus Same as above Lateral side of eyeball Rolls eyeball laterally Oculomotor (VI) Medial rectus Same as above Medial side of eyeball Rolls eyeball medially Oculomotor (III) www.indiandentalacademy.com
  37. 37. Superior oblique (oblique = in this case, muscle fibers running diagonally to long axis of eye ball Same as above Eyeball between superior and lateral recti Rotares eyeball on its axis; directs cornea downward and laterally; note that is moves through a ring of fibrocartilaginous tissue called the trochlea (trochlea = pulley) Trochlear (IV) nerve Inferior oblique Maxilla (front of orbital cavity) Eyeball between inferior and lateral recti Rotates eyeball on its axis; directs cornea upward and laterally Oculomotor (III) nerve www.indiandentalacademy.com
  38. 38. The corrugators is the chief muscle controlling the movements of the eyebrow. A supercilious look of an individual is the result of the contraction of this muscle. The eyebrows are pulled downward and medially, resulting in vertical wrinkles of the forehead. www.indiandentalacademy.com
  39. 39. MUSCLES OF THE NOSE REGION: The four muscles of the nose are very delicate and feeble. They are the procerus, nasalis, dilatoris naris, and depressor septi nasi The procerus has its origin in the bridge of the nose, inserting into the skin between the eyebrows, the glabella. When it contracts, it tends to pull the eyebrows downward, and wrinkles occur over the bridge of the nose. www.indiandentalacademy.com
  40. 40. The nasalis muscle draws the wing of the nose toward the septum. The nares of the nose are compressed by this action, and this compression may be observed during the crying of an infant or the utterance of certain speech sounds. The nostrils are dilated by the action of the two dilatores naris, and the depressor septi nasi draws the septum downward, flattening the philtrum of the maxillary lip and narrowing the nostril. www.indiandentalacademy.com
  41. 41. MOVEMENTS OF LIPS AND CHEEKS MUSCLES Emotion of joy – Joy or happiness may be reflected in individuals in varying degrees, depending upon the intensity of the emotion experienced and the emotional level of the person. The range may be from the quiet warmth of a smile to uproarious laughter, but in either expression, the muscles of the lips and cheeks play a dominant role, and their action is frequently accompanied by a brightening or lighting up www.indiandentalacademy.com of the eyes.
  42. 42. Smile – “Physically and psychologically a smile enhances ones outward appearance and tend to improve self-confidence and feeling self-worth” in general, the movements associated with a smile are lifting or raising motions, producing upward lines which are characteristic of laughter. A smile may be slight and of momentary duration, or it may be intense and prolonged. It may be unaccompanied by sound or it may be a facial overtone during speech resulting in the modifications of certain speech sounds. www.indiandentalacademy.com
  43. 43. In smiling, there is contraction of the zygomaticus major (antagonist: orbicualris oris), which draws the modiolus, and the angle of the mouth upward and backward. The quardatus labii superioris (antagonist: orbicularis oris) elevates the maxillary lip, the corner of the mouth, and the ala nasi. The risorius (antagonist : orbicularis oris) works in synergistic action with the buccinator and draws the angle of the mouth backward, producing a grinning expression which may not of pleasant quality. Its action is associated with smiling and speech but not laughter. www.indiandentalacademy.com
  44. 44. The fibers of the orbicularis oris muscle occupy the entire width of the lips. They extend from the angles of the mouth and run medially across the midline to insert into connective tissue and skin in the ridge area of the philtrum and the septum of the nose. the bulk of the orbicularis oris muscle is made up of a continuation of the fibers of the buccinator muscle as well as all the muscles that insert into the lips. www.indiandentalacademy.com
  45. 45. The arrangement and movement of the fibers are similar in both lips.The convergence of the fibers at the angle of the mouth is known as the modiolus. 14 Muscles radiate from the modiolus like an array of fans.7 www.indiandentalacademy.com
  46. 46. A smile may terminate with the face returning to a state of repose and the modiolus assuming its neutral position. This termination is brought about by the simultaneous contraction of the orbicularis oris muscle and the relaxing of all the muscles contributing to the smiling expression. When the face is in repose, the mandible is in a physiologic rest position. As smiling occurs, the elevating actions of the smiling musculature, working synergistically with the three elevator muscle raise the mandible and retrude it slightly toward the vertical dimension of occlusion, diminishing the interocclusal distance. www.indiandentalacademy.com
  47. 47. Laughing: The smile, instead of terminating, many progress to accelerated proportions in the activity of laughter, which is characterized by the opening of the mouth and separation of the teeth. Lightoller 14, in describing laughter, says that the modioli are drawn cranially and laterally and the maxillary lip forms a straight or somewhat orally convex line stretching from modiolus to modulus. He suggests that the maxillary teeth are exposed as far laterally as the first molar and cranially as far as the gingivae, and even this may be exposed. www.indiandentalacademy.com
  48. 48. The distance between the nasal septum and the red marking of the maxillary lip is very much decreased, and the nasolabial fold is deepened, concaved orally, and extended downward to the rima oris, its cranial portion becoming more horizontal in direction. The mandibular lip is bowed downward, with marked oral concavity, but the mandibular teeth are only slightly exposed or may not be seen. www.indiandentalacademy.com
  49. 49. Emotion of distress – In distress, the mouth is firmly closed. The rima oris is reduced in size to a narrow, cranially bowed slit with the corners of the mouth extending downward. This is caused by (1) the tensing of the muscles inserted in to the modioli which fixes the modioli and (2) the pushing of the mandibular lip under and against the maxillary lip by the superior and inferior portions of the orbicularis oris muscle. The mandibular lip becomes broader laterally and, in so doing, produces creases the continue into the curved depression of the rima oris. This action makes it appear that the angle of the mouth has been dragged www.indiandentalacademy.com downward and laterally.
  50. 50. MOVEMENTS OF TONGUE MUSCLES One of the most versatile and complex of the structures of the stomatognathic system is the tongue. It is the main organ of taste, the chief articulator in speech, and an all-purpose organ in the processes of mastication and deglutition. www.indiandentalacademy.com
  51. 51. Muscles Origin Insertion Genioglossus Geneion = chin; glossus = tongue Mandible Styloglossus (stylo = stake or pole; styloid process of temporal bone) Styloid process of temporal bone Palatoglossus (palato = palate) hyoglossus Undersurface of tongue and hyoid bone Anterior surface of soft palate Body of hyoid bone Side and undersurface to tongue Side of tongue Side of tongue Action Innervation Depresses tongue and thrusts it forward (protraction) Hypoglossal (XII) nerve Elevates tongue and draws it backward (retraction) Hypoglossal (XII) nerve Elevates posterior portion of tongue and draws soft palate down on tongue Pharyngeal plexus Depresses tongue and draws down its sides www.indiandentalacademy.com Hypoglossal (XII) nerve
  52. 52. The root of the tongue is attached to the soft palate, pharynx, hyoid bone, and epiglottis, while the tip, sides, and dorsum are free. The extrinsic muscles (genioglossus, hyoglossus, styloglossus and glossopalatinus) of the tongue, permit wide range of movements, varied in both strength and direction, and rapid and numerous changes in form.Movements of the tongue are facilitated by salivary lubrication. Lessening of such lubrication creates a slowdown in the customary deft and rapid tongue activities occurring in eating and speech. www.indiandentalacademy.com
  53. 53. During the process of mastication, the tongue serves as a greeter, a moistener, a shock absorber, a bracer, a guide, a taster, a crusher, sorter, a mixer, and a disposer. In speech, the autonomous and passive movements of the tongue permit its arching in conjunction with actions of the pharynx and oral cavity to form resonators.15 The tongue also acts with the teeth and hard and soft palates as the articulatory agent responsible for the production of vowel sounds and the majority of consonants. www.indiandentalacademy.com
  54. 54. The great adaptability of the tongue is apparent when teeth are lost and when missing teeth are replaced . With the loss of teeth, the takes over their role in the comminution of food with hard palate in the mortar and pestle type of crushing action. with the insertion of denture, the tongue begins an immediate accomodation to the new perimeters set by the appliance ,thus ensuring that the of eating and speaking may be continued. www.indiandentalacademy.com
  55. 55. It should be noted that the tongue assumes various positions. Although combine action of extrinsic muscle are related to tongue position; the palato glossus muscle is closely associated with tongue position. Wright classified the tongue positions as follows31 Class I – The tongue lies in the floor of the mouth with the tip forward and slightly below the incisal edges of the mandibular anterior teeth. It is considered as normal tongue position. Class II – the tongue is flattened and broadened but the tip is in a normal position. Class III – The tongue is retracted and depressed into the floor of the mouth with the tip curled upward, downward and assimilated in to the body of the tongue. Hypoglossus muscle action may be more strong than styloglossus in this position. In prosthodontic treatment planning, these positions as well as the tongue’s size, rate and range of movement, are all factors requiring consideration15 www.indiandentalacademy.com
  56. 56. MUSCLES THAT MOVE THE MANDIBLE, FLOOR OF THE MOUTH AND THE HEAD The muscle of mastication in association with inframandibular muscles can produce varying degree of mandibular movement in several direction. The kinetic of these muscles help to perform mastication, swallowing and speech and also aid in respiration and expression of emotion. The other major muscle such as sternocleidomastoid and posterior cervical muscles play a major role in stabilizing the skull and enabling controlled movement of the mandible to be performed. Therefore, it is indeed important to know in details about these muscles and their relevant movements. www.indiandentalacademy.com
  57. 57. MUSCLES OF MASTICATION Four pairs of muscles make up a group called the muscles of mastication: (1) Masseter, (2) temporalis, (3) medial pterygoid, and (4) lateral pterygoid. www.indiandentalacademy.com
  58. 58. MASSETER The masseter is a rectangular muscle that originates from the zygomatic arch and extends downward to the lateral aspect of the lower border of the ramus of the mandible. Its insertion on the mandible extends from the region of the second molar at the inferior border posteriorly to include the angle. It is made up of two portion or head: (1) the superficial portion, which consists of fibers that run downward and slightly backward, and (2) the deep portion, which consists of fibers that run in a peredominantly vertical direction. www.indiandentalacademy.com
  59. 59. As fibers of the masseter contract, the mandible is elevated and the teeth are brought into contact. The masseter is a powerful muscle that provides the force necessary to chew efficiently. Its superficial portion may also aid in protruding the mandible. When the mandible is protruded and biting force is applied, the fibers of the deep portion stabilize the condyle against the articular eminence. www.indiandentalacademy.com
  60. 60. TEMPORALIS The temporalis is a large, fan shaped muscle that originates from the temporal fossa and the lateral surface of the skull. Its fibers come together as they extend downward between the zygomatic arch and the lateral surface of the skull to form a tendon that inserts on the coronoid process and anterior border of the ascending ramus. It can be divided into three distinct areas according to fiber direction and ultimate function www.indiandentalacademy.com
  61. 61. The anterior portion consists of fibers that are directed almost vertically The middle portion contains fibers that run obliquely across the lateral aspect of the skull The posterior portion consists of fibers that are aligned almost horizontally, coming forward above the ear to join other temporalis fibers as they pass under the zygomatic arch www.indiandentalacademy.com
  62. 62. When the temporal muscle contracts it elevates the mandible and the teeth are brought into contact. If only portions contract the mandible is moved according to the direction of these fibers that are activated. When the anterior portion contracts, the mandible is raised vertically. Contraction of the middle portion will elevate and retrude the mandible. Function of the posterior portion is somewhat controversial. Although it would appear that contraction of this portion would retrude the mandible, www.indiandentalacademy.com
  63. 63. DuBrul25 suggest that the fibres below the root of the zugomatic process are the only significant one; therefore contraction will cause elevation and only slight retrusion. Because the angulation of its muscle fibres varies, the temporalis is capable of co-ordinating closing movements. Thus it is significant positioning muscle of the mandible. www.indiandentalacademy.com
  64. 64. MEDIAL PTERYGOID The medial (internal) pterygoid originates from the pterygoid fossa and extends downward, backward, and outward to insert along the medial surface of the mandibular angle. When its fibers contract, the mandible is elevated and the teeth are brought into contact. This muscle is also active in protruding the mandible. Unilateral contraction will bring about a mediotrusive movement of the mandible. www.indiandentalacademy.com
  65. 65. LATERAL PTERYGOID The lateral pterygoid is divided and identified as two distinct and different muscles, which is appropriate because their functions are nearly opposite. The muscles are described as the inferior lateral and the superior lateral pterygoids. www.indiandentalacademy.com
  66. 66. Inferior lateral pterygoid: The inferior lateral pterygoid originates at the outer surface of the lateral pterygoid plate and extends backward upward, and outward to its insertion primarily on the neck of the condyle. When the right and left inferior lateral pterygoids contract simultaneously, the condyles are pulled down the articular eminences and the mandible is protruded. Unilateral contraction creates a mediotrusive movement of that condyle and causes a lateral movement of the mandible to the opposite side. When this muscle functions with the mandibular depressors, the mandible is lowered and the condyles glide forward and downward on the articular eminences. www.indiandentalacademy.com
  67. 67. SUPERIOR LATERAL PTERYGOID The superior lateral pterygoid is considerable smaller than the inferior and originates at the infratemporal surface of the greater sphenoid wing, extending almost horizontally, backward, and outward to insert on the articular capsule, the disc and the neck of the condyle. The exact attachment of the superior lateral pterygoid to the disc is somewhat debated. Although some authors 30 suggest no attachment, most studies reveal the presence of the muscle and disc attachment. www.indiandentalacademy.com LITERATURE
  68. 68. Although the inferior lateral pterygoid is active during opening the superior remains inactive becoming active only in conjunction with the elevator muscles. The superior lateral pterygoid is especially active during the power stroke and when the teeth are held together. The power stroke refers to movements that involve closure of the mandible against resistance, such as in chewing or clenching the teeth together. www.indiandentalacademy.com
  69. 69. It is to note that the pull of the lateral pterygoids on the disc and condyle is in a significantly medial direction. As the condyle moves more forward, the medial angulation of the pull of these muscles becomes even greater. In the wide-open mouth position, the direction of the muscle pull is more medial. It is interesting to note that approximately 80% of the fibers that make up both lateral pterygoid muscles are slow muscle fiber (type I) 23 This suggests that these muscles are relatively resistant to fatigue and may serve to brace the condyle for long periods of time without difficulty. www.indiandentalacademy.com
  70. 70. It is essential for a prosthodontist to be fully aware not only of the basic mandibular movements and positions but also of functional patterns of movements, in which variations may occur because of emotional state or physiologic needs. These varying patterns may be noted in either extent of movement or rate of speed at which it takes place. Such motion patterns are dislodging forces which must be anticipated in the design of any that must absorb them and still maintain a degree of stability and retention. www.indiandentalacademy.com
  71. 71. MUSCLES OF THE FLOOR OF THE ORAL CAVITY www.indiandentalacademy.com
  72. 72. SUPRAHYOID & INFRAHYOID MUSCLES These muscles suspend the hyoid bone, lower the mandible, and have prosthodontic significance in relation to physiologic rest position. speech, facial expression, mastication and deglutition. The suprahyoid muscles consist of the digastric, stylohyoid, mylohyoid and geniohyoid muscles. They are depressors of the mandible and elevators of the hyoid bone. The infrahyoid muscles are the sternohyoid, sternothyroid, omohyoid and thyrohyoid muscles. They depress the hyoid bone and larynx and fix the hyoid bone so that the suprhyoid muscles may act upon the mandible. www.indiandentalacademy.com
  73. 73. These are voluntary muscles but act reflexively and, during mandibular rest position, are in balance with the supramandibular muscles. The interocclusal distance is due to the equal tonicity of the supramandibular and the inframandibular muscles. As compared with the closing muscles of the mandible, these are very small and weak. They are used for rapid movements and those of long duration. In old age, the supramandibular muscles increase in tonicity, while the inframandibular muscles decrease. www.indiandentalacademy.com
  74. 74. The vertical tug of war which takes place in the opening and closing movements of the mandible is produced by the elevators of the mandible (the temporalis masseter, and internal pterygoid) and the depressor of the mandible (the geniohyoid mylohyoid and digastric) the external pterygoid muscles move the mandible forward, while the posterior fibers of the temporalis retrude the mandible. The external pterygoid and the elevators opposite them produce the side to side or lateral movements. These movements are basic and are governed neurologically by a central regulator, which receives impulses through the various physiologic reflex arcs. www.indiandentalacademy.com
  75. 75. MUSCLES THAT MOVE THE HEAD www.indiandentalacademy.com
  76. 76. Mandibular movements are limited and modified by the temporomandibular articulations posteriorly and the teeth anteriorly. The mandible assumes various positions, which serve as starting, limiting, and returning points in its complex physiologic activities. Those on to vertical plane are physiologic rest position and vertical dimension of occlusion. Those on a horizontal plane are centric relation (which also has a vertical component) and right and left lateral and protrusive positions. All of these mandibular movements and positions occur within the perimeter of extreme movements, which the mandible is capable of performing. www.indiandentalacademy.com
  77. 77. POSTERIOR CERVICAL MUSCLES The head rests upon the atlas, the uppermost vertebra of the spinal column, in positional unbalance because the center of gravity of the head is not directly over the atlas, but anterior to it, in the approximate region of the temporomandibular articulation. The weight of the projecting mandible and teeth suspended from this region lies about in the center of the entire polyfunctional pyramid, 14-16 thus contributing to this unbalance. www.indiandentalacademy.com
  78. 78. The structures responsible for maintaining the head in balance are the posterior cervical muscles working antagonistically to the supramandibular and inframandibular muscles. Thus, if one falls asleep in an upright position, and the musculature controlling this balance relaxes, gravity pulls the head forward and the mandible down. The posterior cervical muscles function continuously approximately two-thirds of each day, maintaining the heavy head in balance. They are also responsible for the many and delicate positioning of the head associated with the activities of expression, eating, breathing, vision, hearing, gait, and posture. Prosthodontically, little concern is evidenced for these muscles as www.indiandentalacademy.com contrasted with the interest displayed in their antagonists.
  79. 79. MUSCLES THAT MOVES THE SOFT PALATE Muscles Origin Levator veli palatani Levetor = rouses Velum = veil Palato -palat Petrous portion of temporal bone and medial wall of auditory tube Tensor veli palatini Tensor makes tense Medial pterigoid plate of sphenoid bone, spine of sphenoid, lateral wall of auditory tube Insertion Action Innervation Blend with corresponding muscle of opposite side Rlevate soft palate during swallowing Pharyngeal plexus Palatine oponeuosis and palatine bone Tenses (tightens soft palate during swallowing Mandibular branch of trigeminal (V) nerve Muscular avule (urulac urula) Posterior border of the hard palate and palatine oporeurosis Uvula Tenses (tighten and raises uvula ) Pharyngeal plexus Platoglossus (palato = plate; glossus = tongue Anterior surface of soft palate Side of tongue Elevates posterior portion of tongue and draws soft palate down on tongue Pharyngeal plexus Palatopharyngeus (pharyngo = pharynx Elevates larynx and Posterior border of Posterior border of pharynx and hard palate thyroid cartilage helps close and palatine and lateral and www.indiandentalacademy.com nasopharynx aponeurosis posterior wall of during pharynx Pharyngeal plexus
  80. 80. Musculature of the soft palate is divided into two functional groups, the depressors and elevators. The depressors are extrinsic muscles, the glossopalatinus and pharyngopalatinus, which extend laterally, and inferiorly into the tongue and pharynx, of which they are an integral part. The contraction of these muscles elevates the tongue, pharynx, and larynx and depresses the soft palate, thus narrowing the isthmus of the fauces. The elevators of the soft palate, the tensor and lavator veli palatini and the musculus uvulae, are primarily contained within the soft palate. www.indiandentalacademy.com
  81. 81. The tensor veli palatini, as the name implies, flattens tenses, and lowers the soft palate and at the same time opens the Eustachian tube. The levator veli palatini raises the soft palate increases its arch, and articulates the velum border with the posterior wall of the pharynx. The musclulus uvulae shortens. Tenses, and raises the uvula. www.indiandentalacademy.com
  82. 82. Based on the degree of flexure the soft palate makes with the hard palate and the width of the palatal seal area, soft palate can be classified 31 Class I : the soft palate is rather horizontal and demonstrates little muscular movement. Class II: The soft palate turns downward at about a 45 degree angle to the hard palate and the amount of potential tissue coverage for the palatal seal is less than for class I. Class III: The soft palate turns downward sharply at about a 70-degree angle just posteriorly to the hard palate. Since this is the most acute relation the soft palate makes with the hard palate, the musculature must make the most elevation to effect velopharyngeal closure. So, the available space for coverage by the posterior border and this is considered as the least favorable soft palate form. www.indiandentalacademy.com
  83. 83. The kinetic of the soft palate in coordination with tongue muscle and muscle of pharynx and larynx play a major role during the process of eating, breathing www.indiandentalacademy.com and speech
  84. 84. MUSCLES OF PHARYNX Muscles Circular layer Inferior constrictor (inferior = below; constrictor = decreases diameter of a lumen Middle constrictor Superior constrictor (Superior = above) Origin Insertion Action Innervation Posterior median raphe of pharynx Constricts inferior portion of pharynx to propel a bolus into esophagus Pharyngeal plexus Posterior median raphe of pharynx Constricts middle portion of pharynx to propel a bolus into esophagus Pharyngeal plexus Pterygoid Constricts process, superior pterygomand Posterior median portion of ibular raphe, raphe of pharynx to and pharynx propel a mylohyoid bolus into line of esophagus mandible www.indiandentalacademy.com Pharyngeal plexus Cricoid and thyroid cartilages of larynx. Greater and lesser cornu of hyoid bone and stylohyoid ligament.
  85. 85. Longitudinal layer Stylopharyngeus (stylo = stake or pole; styloid process of temporal bone; pharyngo = pharynx ) Salipingopharyng eus (salping = pertaining to the auditory or uterine rube) Palatopharyngeus (palato = palate) Lateral aspects of pharynx and thyroid cartilage Elevates larynx and dilates pharynx to help bolus descend. Glossopharyngeal (IX) nerve. Posterior fibers of palatopharyn geus muscle. Elevates superior portion of lateral wall of pharynx during swallowing and opens orifice of auditory (Eustachian) tube Pharyngeal plexus Elevates larynx Posterior border and pharynx of thyroid and helps cartilage and close lateral and nasopharynx posterior wall during of pharynx www.indiandentalacademy.com swallowing Pharyngeal plexus Medial side of base of styloid process. Inferior portion of auditory (Eustachian) tube Soft palate
  86. 86. MUSCLES OF LARYNX Muscles Origin Insertion Action Extrinsic Omohyoid (omo = relationship to the shoulder; byoedes = Ushaped; per taining to hyoid bone) Superior border of scapula and superior transverse ligament. Body of hyoid bone Depresses hyoid bone Branches of ansacervicalis nerve (C1-C3) Sternohyoid (sterno = sternum) Medial end of clavicle and manubrium of sternum Body of hyoid bone Depresses hyoid bone Branches of ansacervicalis nerve (C1-C3) Manubrium of sternum Thyroid cartilage of larynx Depresses thyroid cartilage Branches of ansacervicalis nerve (C1-C3) Elevates thyroid cartilage and depresses hyoid bone Branches of ansacervicalis nerve (C1-C2) and descending hypoglosal (XII) nerve Sternoothyroid (thyro = thyroid gland ) Thyrohyoid Thyroid cartilage of larynx Greater cornu of hyoid bone www.indiandentalacademy.com Innervation
  87. 87. Anterior and lateral portion of cricoid cartilage of larynx Anterior border of inferior cornu of thyroid cartilage of larynx and posterior part of inferior border of lamina of thyroid cartilage Produces tension and congation of vocal folds External laryngeal branch of vagus (X) nerve Posterior cricoarytenoid (arytaina = shaped like a jug) Posterior surface of cricoid cartilage Posterior surface of muscular process of arytenoids cartilage of larynx. Opens glottis Recurrent laryngeal branch of vagus (X) nerve Lateral cricoary tenoid Superior border of cricoid cartilage Anterior surface of muscular process of arytenoids cartilage Closes glottis Recurrent laryngeal branch of vagus (X) nerve Arytenoids Posterior surface and lateral border of one arytenoids cartilage Corresponding parts of opposite arytenoids cartilage Closes glottis Recurrent laryngeal branch of vagus (X) nerve Thyroaryytenoid Inferior portion of angle of thyroid cartilage and middle of cricothyroid ligament Base and anterior surface of arytenoids cartilage Shortens and relaxes vocal folds. Recurrent laryngeal branch of vagus (X) nerve Intrinsic Cricothyroid (crico = cricoid cartilage of larynx) www.indiandentalacademy.com
  88. 88. www.indiandentalacademy.com
  89. 89. The process of eating can be divided into (1) premasticatory (2) masticatory (3) swallowing activities associated with the intake of food and preparation for its entrance into esophagus. The premasticatory phage begins before the act of eating start. The masticatory phage is a series of highly coordinated functions in the process of chewing food or swallowing and digestion www.indiandentalacademy.com
  90. 90. SWALLOWING (DEGLUTITION) Swallowing is a series of coordinated muscular contractions that moves a bolus of food from the oral cavity through the esophagus to the stomathic. It consists of voluntary, involuntary and reflex muscular activity. Stabilization of the mandible is an important part of swallowing. The mandible must be fixed so that contraction of the suprahyoid and infrahyoid muscles can control proper movement of the hyoid bone needed for swallowing. The normal adult swallow that uses the teeth for mandibular stability has been called the somatic swallow. When teeth are not present, as in the infant, the mandible must be braced by other means. In the infantile swallow, or visceral swallow, the mandible is braced by placing the tongue forward and between the dental arches or gum www.indiandentalacademy.com pads.
  91. 91. Although swallowing is one continuous act, for purposes of discussion it is divided into three stages. 23 First Stage: The first stage of swallowing is voluntary and begins selective parting of the masticated food into a mass or bolus. This separation is performed mostly by the tongue. The bolus is placed on the dorsum of the tongue and pressed lightly against the hard palate. The tip of the tongue rests on the hard palate just behind the incisors. The lips are sealed and the teeth are brought together. The presence of the bolus on the mucosa of the palate initiates a reflex wave of contraction in the tongue that presses the bojus backward. As the bolus reaches the back of the tongue, it is transferred to www.indiandentalacademy.com the pharynx.
  92. 92. Second stage: Once the bolus has reached the pharynx a peristaltic wave caused by contraction of the pharyngeal constrictor muscles carries it down to the esophagus. The soft palate rises to touch the posterior pharyngeal wall, sealing off the nasal passages. The epiglottis blocks the pharyngeal airway to trachea and keeps the food in the esophagus. During this stage of swallowing, the pharyngeal muscular activity opens the pharyngeal orifices of the Eustachian tubes, which are normally closed. It is estimated that these first two stages of swallowing together last about 1 second www.indiandentalacademy.com
  93. 93. Third stage: the third stage of swallowing consists of passing the bolus through the length of the esophagus and into the stomach. Peristaltic waves carry the bolus down the esophagus. The waves take 6 to 7 seconds to carry the bolus through the length of the esophagus. As the bolus approaches the cardiac sphincter, the sphincter relaxes and lets it enter the stomach. It the upper section of the aesophagus, the muscles are mainly voluntary and can be used to return food to the mouth when necessary for more complete mastication. In the lower section the muscles are entirely involuntary. www.indiandentalacademy.com
  94. 94. CLINICAL APPLICATIONS OF CONCEPT OF KINETIC The diagnostic phase: Diagnosis begins when the Prosthodontist first views his patient. At this moment, he receives immediate mental impressions relative to the patient’s general physical appearance, age, gait posture, coloring, facial contours, etc. These are observations based on external signs and symptoms revealed in surface anatomy. Changes in surface anatomy which are caused by loss of support from natural tissues or their artificial substitutes are evident when an adequate diagnosis is made. www.indiandentalacademy.com
  95. 95. Some of the external evidences of loss of supporting structures are sunken cheeks, flattened lips, decrease in the width of the vermilion border of the lips, increased depth of folds and grooves in the face, and a decrease of occlusal vertical dimension, producing changes in facial proportions and bringing the nose closer to the chin. www.indiandentalacademy.com
  96. 96. However, lack of support may not always be the entire cause of some of the sings and symptoms apparent in surface anatomy. Inherited tendencies can exert strong influences on surface markings, such as folds and grooves or lip contours. It is important to determine whether surface markings are the result of supportive loss or are inherited characteristics of the individual. www.indiandentalacademy.com
  97. 97. This will affect the prosthodontic treatment because any attempt to provide support artificially where there has been no loss of support will result in eradication of natural contours, which are characteristic of the patient. Pre-extraction photographs of the patient are aids in making this evaluation. Losses of elasticity of the skin and muscular tonicity are also apparent in studying skin texture and tone and result from loss of supporting structures. www.indiandentalacademy.com
  98. 98. External evidences of temperament and tension – In general, the direction of the lines of the face can be taken as indicative of the individual’s emotional makeup or temperament. A person with a happy disposition, accustomed to smiling and laughing has facial lines with the upward cast characteristic of mirth. 18 Conversely, the person with a dour personality is likely to have facial lines with a downward slant associated with sorrow or grief. www.indiandentalacademy.com
  99. 99. Observation of these facial markings in the initial diagnosis provides a clue to the temperament of the patient and suggests problems, which may be encountered in determining the proper amount of support by the denture for the facial structures in order to preserve or minimize certain facial lines. Symptoms of stresses or tensions are frequently apparent in the surface anatomy of the face and neck. These symptoms include taut lines about the mouth, tightly compressed lips, teeth held almost continuously in contact with a resultant loss of vertical dimension of occlusion, and strained musculature in the neck region. www.indiandentalacademy.com
  100. 100. OTHER INDICATION FROM SURFACE ANATOMY This involves the muscle attachments within the oral cavity, the strength and amount of tongue activity, and the dislodging forces that may be exerted on dentures by the muscles of facial expression and craniomandibular muscles. The eyes are frequently the most expressive features of the face. They may gain in attractiveness in the aging process, while the mouth may become less attractive. Although distant from the mouth, the eyes do have significance in prosthodontic diagnosis and treatment. Asymmetry of the face may be apparent in the eyes, since their shape contributes to the www.indiandentalacademy.com general contour of the face.
  101. 101. Any asymmetry of the eyes observed in diagnosis should be noted so that necessary allowances can be made when the pupils of the eyes are used as reference points in building occlusion rims or in positioning teeth. Thus far, external signs and symptoms apparent in the first view of the static surface anatomy have been considered. However, when the patient begins to speak, a new source of diagnostic aids becomes available. For it is then that he begins to reveal himself as a distinct personality, characterized by individual habits of facial expression, speech, and www.indiandentalacademy.com mannerisms.
  102. 102. The speech and facial expressions of the patient may be studied during the initial interview. An analysis of these functions, to be meaningful, must be based on a normal unstrained performance. The patient must be put at ease, and his interest must be directed toward his own problems. in recounting these, he is likely to become concerned to the extent of dropping any strained or false mannerisms of expression. The request “Tell me about your teeth” generally accomplishes this purpose. During the patient’s response a twofold evaluation is made: the first is based upon factual information supplied by the idea content of the spoken words the second is based on the quality of voice and speech plus the many and varied movements of the face accompanying the speech performance. www.indiandentalacademy.com
  103. 103. SPEECH AND PATIENT CLASSIFICATION Speech sometimes serves as an aid in the initial classification of the patient 18. Rapid jerky speech is frequently characteristic of the hysterical patient. The exacting patient often displays forcefulness and abrupt speech qualities in placing his question and stating his demand .In contrast to these patients, the speech of the philosophic or indifferent patient is less forceful and of the more even rate. The indifferent patient frequently has monotone quality in his speech, which may occur as a result of his lack of interest and certainly reflects the absence of enthusiasm. www.indiandentalacademy.com
  104. 104. SPEECH DEFECTS Many persons are not aware that they have speech defects. Preoperative speech recordings during the preliminary interview enable the patient to hear his own voice as it sounds to others and to note defects of which he may not have been aware Some speech defects are accompanied by changes in facial expression, and they result from (1) a defective dentition (2) defective dentures (3) ill health or (4) geriatric changes. www.indiandentalacademy.com
  105. 105. A patient who has lost most of the teeth and has never had them replaced reflects speech modifications. During the period in which the teeth have been lost, he has been forced to make certain adaptive movements to compensate for these losses in order to continue to engage in understandable speech. The ability to accommodate when oral structures are lost is evidenced by the fact that people with no teeth or with ill-fitting dentures continue to speak and to be understood. www.indiandentalacademy.com
  106. 106. EFFECTS OF LOSS OF TEETH ON OTHER SPEECH ARTICULATORS The loss of posterior teeth results in spreading of the tongue. The loss of anterior teeth and supporting structures reduces lip support. The failure to replace missing teeth causes a drifting of remaining teeth and changes in occlusion. Thus, three of the main articulators in speech (tongue, lips, and teeth) have been modified. The fundamental role of these articulators is in the production of conosonantal sounds, which require impedance or checking of the airstream to www.indiandentalacademy.com occur.
  107. 107. DEFECTS IN PRONUNCIATION OF CERTAIN CONSONANTS Even under ideal conditions, i.e. when a speaker has a full complement of natural teeth in near normal positions, the consonants s and z present more difficulty in pronunciation and are less pleasing to the ear than any other consonants. 18 It follows, therefore, that the consonants s and z are of major concern in prosthodontic treatment. Defects in their pronunciation by denture patients may be caused by (1) the inability of the tongue and lips to perform precise, firm movements in directing the stream of air, (2) too large an interocclusal distance (3) missing or malpositioned teeth (4) wide diastemas, (5) lack of auditory acuity. www.indiandentalacademy.com
  108. 108. Defects in the pronunciation of the consonants f and v are most often caused by the inability of the mandibular lip to contact the maxillary incisors properly. Observation should be made of the length and position of the maxillary anterior teeth while the patient is saying “five” and “valve” or words which contain these labiodental sounds. The teeth should come into slight end-to-end contact with the center of the mandibular lip. www.indiandentalacademy.com
  109. 109. Defects in the pronunciaton of the consonants t and d are often due to placement of the maxillary anterior teeth too far palatally. These linguopalatal sounds are produced when the tongue articulates against the maxillary teeth and palate. Therefore, if the tongue contacts the teeth and palate too soon, the sound cannot be made properly www.indiandentalacademy.com
  110. 110. FACIAL EXPRESSION There are many reasons for including facial expression in the functional analysis of the patient. Movements of facial expression are generally habitual. They are frequently vigorous movements employing muscles adjacent to dentures and can, therefore, exert dislodging pressures. The activity of facial expression is engaged in many hours of the day, as is speech. A deteriorating dentition or unsightly dentures can be responsible for an individual acquiring compensatory facial expressions to www.indiandentalacademy.com conceal a dental deformity.
  111. 111. SIGNIFICANT FACIAL MOVEMENT Certain types of facial movements have particular significance in treatment planning. Exaggerated movements of the cheeks, lips and tongue during speech must be noted so as to incorporate them in the dentures. www.indiandentalacademy.com
  112. 112. HABITUAL FACIAL EXPRESSION “Masticatory muscle hyperactivity is thought to produce muscle pain and tension headaches and can cause excessive wear or breakage of restorative dental materials used in the treatment of prosthodontic patients. The quantification and identification of this type of activity is an important consideration in the preoperative diagnosis and treatment planning phase of prosthodontic care.” 9 Habitual facial expressions employing exaggerated movements of the elevators and depressors of the lips can be dislodging forces to dentures unless these movements are recognized and allowances are made for them. www.indiandentalacademy.com
  113. 113. DIAGNOSTIC EVALUATION OF THE EDENTULOUS MOUTH Three acts are performed almost simultaneously in the examination of an edentulous mouth: (1) observation, (2) interpretation (3) visualization . All these three act should be thoroughly evaluated for a (i) Evidence of a structural loss (ii) Structural changes (iii) Relationship changes, www.indiandentalacademy.com
  114. 114. The amount of space between the residual alveolar ridge and the lips during functional activities must be considered in relation to the denture flanges. Dentures are frequently constructed with the lips in repose and without regard for overactive mentalis muscles. These muscles, when functioning, will reduce the labial vestibular space and tend to dislodge the mandibular denture. 10 The overfilling of this vestibular space with the denture flanges and malpositioning of the teeth can have a marked effect on speech, particularly in plosive and f and v sounds. If overfilled, it will eradicate the normal mentolabial sulcus. www.indiandentalacademy.com LITERATURE
  115. 115. MODIOLUS In an edentulous mouth, the modioli assume a sagging position, become less active, diminish in size, and change in shape. This malposition and loss of tonicity caused by lack of tooth support can produce leakage of food liquids, and saliva at the corners of the mouth and result in angular cheilosis and a downward cast in these regions. A digital examination of the modiolus is made by placing the index finger in the buccal pouch or vestibule on the inner surface of the cheek and the thumb on the outer surface of the cheek and directing the patient to swallow. Observations of these highly functional landmarks should be made in relation to their size, development and flexibility. www.indiandentalacademy.com
  116. 116. The mandibular denture should be visualized in relation to the allowance necessary to accommodate for this muscle mass. The modioli can be used to an advantage in stabilizing the maxillary dentures by placement of the maxillary premolars in a position above them. Thus, during functional activities involving elevation of the lips, there are fixing and elevation of the modioli and uplifting of the maxillary denture. By directing the patient to smile, the Prosthodontist can use the modioli as reference point in determining the occlusal plane to develop the smiling line. The application of these two principles changes the shape of the mouth by uplifting its corners and creating more pleasant contours www.indiandentalacademy.com
  117. 117. The tongue is a powerful and extremely adaptable organ. Observation of the position of the tongue should be made with the mouth relaxed and about half open. If the tongue is in a retruded position, it may dislodge the mandibular denture by raising the lingual flanges and permitting air to get under them. However, it the tongue is in a forward position, resting on the mandibular anterior ridge, it will serve as a stabilizer to the mandibular denture. Because of the great adaptability of the tongue, patients may be trained by conditioning exercises to reposition the tongue from an unfavorable to a more favorable position. www.indiandentalacademy.com
  118. 118. During swallowing, the teeth serve as limiting boundaries to the inward movements of the cheeks and lips and to the upward and outward movements of the tongue and sublingual structures. The region housing the teeth and alveolar supporting structures has been called variously “the neutral zone”, “a dead space” and “the potential denture space” www.indiandentalacademy.com
  119. 119. This space is difficult to located because of (1) the changes in the alveolar ridge, (2) the approximation of the tongue and cheeks in their attempts to fill this region, (3) the reorientation of muscular attachments which changes the structural relationships, (4) the constantly changing shape and position of the tongue during functional activities and (5) the closed position of the lips during certain of these activities. www.indiandentalacademy.com
  120. 120. The structures under the tongue are of concern particularly when they are in an abnormal functional relationship to the mandibular ridge. Because of the comparative delicacy of these structures, they are difficult to record without displacement. www.indiandentalacademy.com
  121. 121. As the residual alveolar ridge becomes smaller, these sublingual structures become more dominant in their functional relation to the residual ridge. When these unfavorable conditions are observed, consideration must be given to them both before and during the construction of dentures. The size or form of the hard palate and its relation to soft palate should be observed and interpreted. www.indiandentalacademy.com
  122. 122. CLINICAL APPLICATION OF CONCEPTS OF KINETIC The recording phase: The recording phases can be considered as a continuous diagnostic phage since they permit to learn more about the patient as the procedures are performed. They furnish the opportunities to observe patients willingness and ability to carryout instruction, reflex responses healing capacities and his adaptability possibilities. 19 The recording phases start with the making of primary impression followed by border moulding and making of final impression and registration of jaw registration records. www.indiandentalacademy.com
  123. 123. IMPRESSION The impression procedures must adhere to the following biological principles (Boucher C.O) 5 dictated by the anatomy and physiology of the edentulous mouth so as to enhance the retention, stability and support of a denture. 1.The impression is extended to include all of the basal seat within the limits of the health and functions of the supporting and limiting tissues. 2.The borders are in harmony with the anatomic and physiologic limitations of the oral structures. www.indiandentalacademy.com
  124. 124. 3.A physiologic type of border-moulding procedure is performed by the prosthodontist or by the patient under the guidance of the prosthodontist. 4.Proper space for the selected final impression material is provided within the impression tray. 5.Selective pressure is placed on the basal seat during the making of the final impression. 6.The impression can be removed from the mouth without damage to the mucous membrane of the residual ridge. www.indiandentalacademy.com
  125. 125. 7.A guiding mechanism is provided for correct positioning of the impression tray in the mouth. 8.The tray and final impression are made of dimensionally stable materials. 9.The external shape of the final impression is similar to the external form of the completed denture. www.indiandentalacademy.com
  126. 126. PRIMARY IMPRESSION When a primary impression is made for preparation of a custom tray for final impressions, the objectives are to all areas to be covered by the adjacent landmarks with an impression material that is accurate and incorporate the minimum of tissue displacement. So the right (stock) tray should be selected and modified (and border should be beaded with soft wax) to fulfill our objectives. The impression tray should be approximately 6 mm. larger then the outside surface of the residual alveolar ridge when alginate is chosen as the impression material. www.indiandentalacademy.com
  127. 127. The maxillary impression should include the hamular notches, fovea palatina, entire buccal vestibule, including the aforementioned retrotubercle sulcus, fernum attachments, palate and entire labial vestibule. The mandibular impression should include the retromolar pads. The buccal shelf areas, the external oblique ridges, frenum attachments sublingual space, retromylohyoid space, the posterior mucous membrane floor of the mouth to include and be below the mylohyoid line and the entire labial and buccal vestibules. www.indiandentalacademy.com
  128. 128. All the functional movement of the lips, cheeks and the tongue should be recorded by allowing the patient to do the same movement during impression making after the tray is stabilized. Any exaggerated movements that are noted during diagnostic phage must be recorded in the same way. www.indiandentalacademy.com
  129. 129. BORDER MOULDING AND FINAL IMPRESSION www.indiandentalacademy.com Schematic presentation of border moulding
  130. 130. www.indiandentalacademy.com Schematic presentation of border moulding
  131. 131. The border moulded final impression tray should be so formed that it supports the cheeks and lips in the same manner as the finished denture will do. The lingual surface of the mandibular tray should be shaped so that it guides the tongue into the same position it will occupy in relation to the finished denture. 24 www.indiandentalacademy.com
  132. 132. It should be possible for the patient to wipe with the tip of the tongue across the vermilion border of the upper lip with the tray in place in the mouth without noticeable displacement of the tray. An approximate 0.5 mm of border moulding material should be removed from around the border and final impression is made. All the functional movement of the tongue cheeks and lips should be recorded in the same way as in the primary impression. www.indiandentalacademy.com
  133. 133. RECORDING OF MAXILLOMANDIBULAR RELATION Provisional vertical dimension of physiologic rest position In recording maxillomandibular relation by physiologic method, the vertical dimension of the rest position is first registered. It is the vertical separation of the two jaws, which exist when the entire mandibular musculature is in a state of tonic contraction. After each of the functional activities of swallowing, speaking, and breathing the patient’s mandible assumes a resting position by being suspended by the equal tonicity of its musculature. When the lips are in slight contact with each other facial measurements are recorded between two landmarks, the base of the nose and the mentolabial sulcus. This measurement is a provisional reference point from which the recording of the vertical dimension of occlusion may www.indiandentalacademy.com be related.
  134. 134. SWALLOWING The act of swallowing is used initially because it provides a more natural action to determine the height of the mandibular occlusion rim. The occlusal surface of the mandibular occlusion rim is uniformly softened in a warm water bath, and the occlusion rim is placed in the patient’s mouth. With the maxillary occlusion rim in place, the patient is asked to swallow several times. The space between the tow facial reference points is determined and recorded. The swallowing procedure should be repeated if necessary. The occlusion rims are removed from the patient’s mouth, and separated www.indiandentalacademy.com
  135. 135. Phonetics: certain speech sounds may serve as an aid in recording physiologic rest position. Speech containing ‘m’ sounds brings the lips together and positions the mandible in physiologic rest. The patient is instructed to say a series of m sounds until he experiences fatigue sensations at which time a measurement is made. Breathing: Facial measurements obtained immediately after the patient has inhaled and exhaled several times serve as additional aids in recording physiologic rest www.indiandentalacademy.com position.
  136. 136. Vertical dimension of occlusion Provisional vertical dimension of occlusion can be obtained using speech activities similar to those used in recording the physiologic rest positions. Phonetics The patient is asked to count rapidly from 45 to 70 observation should be made by standing slightly to the side of the patient. During the speech performance, there should be 3-4 mm. gap between the two occlusal rims. It is important to observe for any interferences that can occur during the utterance of s sound as in 46, 56, 66…. If interference is noted, the occlusion rims should be reduced in height until there is a slight clearance when the patient makes the s sounds. www.indiandentalacademy.com
  137. 137. CLINICAL APPLICATION OF CONCEPTS OF KINETIC The final phases of denture construction Although certain esthetic factors may be considered with the face in the static state, final esthetic determinations should never be made with the face in repose. The vital movements associated with speech and facial expression are actually esthetics in action. Dentures must serve in harmony with such functions. Therefore, the mouth www.indiandentalacademy.com in action must be the testing environment.
  138. 138. LIP SUPPORT Adequate lip support involves more than a concern for esthetics physiologically, the functions of speech, facial expression, eating and breathing are all affected by it. The main objectives in establishing adequate lip support are to obtain and maintain the natural harmonies of the lips and cheeks during the complex interplay of the musculature in functional performances. 20 www.indiandentalacademy.com
  139. 139. The framework of musculature chiefly responsible for the contours and movements of the lips is the orbicularis oris which is composed of the interlacing fibers of all of the muscles of the lips. Because of its complexity, Sicher25 has described the orbicularis oris as a muscle, which “is only functionally but not anatomically a unit”. In order to apply the principle of muscular efficiency ,it becomes imperative that this functioning unit be held in the natural position it occupied during its development when it was supported by the natural teeth and supporting structures. www.indiandentalacademy.com
  140. 140. In considering problems of lip support, more attention is generally accorded to the maxillary lip than to the mandibular lip. Pursing and sphincter actions of the lips and symmetrical outlines of their muscle fibers may suggest that the two lips function in a similar fashion. The elevating action produced in the mandibular lip by the mentalis muscle is one evidence that this is not so. www.indiandentalacademy.com
  141. 141. The mandibular lip, bounded laterally by the labiomarginal sulci, the rima oris above, and the mentolabial sulcus below, is usually smaller and more active than the maxillary lip. The relative sizes, shapes and surface outlines of the two lip change during functional movements. The correct support is provided where structural loss exists by proper positioning of the labial surfaces of the mandibular anterior teeth. In instances where a marked resorption of the residual ridge has occurred, resulting in a lowering of the reflective tissues of the labial vestibule to a level with or below the mentolabial sulcus, the sulcus can be eradicated by overfilling the vestibular region with the denture flange. This is not advisable form the standpoint of esthetics or function. www.indiandentalacademy.com
  142. 142. GUIDELINES FOR DEVELOPING ADEQUATE LIP SUPPORT 1.The following guides may be used in establishing adequate lip support. 2.The best aids will be found the information revealed in study casts and photographs of the natural teeth. 3.The same dimension and contours of the functional occlusion rims should be maintained by the anterior teeth to preserve static dynamic facial length 4.The arch form of the teeth should follow the arch form of the residual ridge. www.indiandentalacademy.com
  143. 143. 4.The labial surfaces of the teeth should be 8 to 10 mm. in front of incisive papilla and should be out as far or in front of the labial flange. 5.The midline of the teeth is usually in the same sagittal plane as the incisive papilla and the midline of the face. 6.The distance from the necks of the anterior teeth to the residual ridge is governed by the amount of resorption of the ridge 7.The incisal edges of the maxillary and mandibular teeth should approach each other, but not contact, during the pronunciation of words containing the sibilants s, z, zh, ch and j www.indiandentalacademy.com
  144. 144. 8.The length of the maxillary anterior teeth and the amount which shows below the lip should be checked by having the patient say words beginning with f and v. If the f sounds like v, the teeth are too long 9.If th, as in these and those, sounds like d, the teeth are positioned too far palatally 10.The teeth should be positioned until there is no space between teeth and lips during normal lip movements in performing these phonetic functions www.indiandentalacademy.com
  145. 145. SURFACE ANATOMY INDICATIONS OF THE AMOUNT OF LIP SUPPORT External evidences which assist in critically evaluating the amount of lip support provided by the denture bases and the teeth may be studied with the face in repose. The corners and the vermillion borders of the lips, the philtrum, the mentolabial, nasolabial, and labiomarginal sulci are surface markings, which must be considered. Indications of insufficient support include: a perpetuation of the general appearance of collapse around the mouth region; a reduction of the size of the vermillion borders of the lips; a drooping of the corners of the mouth; a deepening of the sulci; and an obliteration of the philtrum. www.indiandentalacademy.com
  146. 146. Indications of too much support include: tensed, stretched appearance of the lips which can result in tension lines around the mouth; distortion of the philtrum; obliterations of the sulci; and an eradication of the natural contours of the lower part of the face that serve to correlate that portion with the upper part of the face. This correlation is the constant toward which our esthetic efforts must be directed. www.indiandentalacademy.com
  147. 147. Maxillomandibular relation records are verified by observing the phase in repose and in function. The amount of support is evaluated in relation to evidence of collapse of stretched, strained areas. Lip contours and the approximation of the lips in phonetic performance are checked Clinical observations are made of the amount of tongue space. If the tongue has been crowded, there is likely to be a space between the teeth and cheeks in the posterior region, or the teeth and the lips in the anterior region, or both. The tongue will appear crowded, humped and retruded, and there will be apparent difficulty in swallowing. www.indiandentalacademy.com
  148. 148. If the vertical dimension of occlusion is decreased, there will be inadequate tongue space. This condition will cause frequent “strained” swallowing and a frequent return to the vertical dimension of rest position. If strained swallowing movements are noted, clinical verification of the interocclusal distance may be made by having the patient say “sixty six”. More than likely, there will be evidence of too much interocclusal distance. www.indiandentalacademy.com
  149. 149. THE POLISHED SURFACES All three surfaces of the dentures i.e., the impression, the occlusal and the polished surfaces, should fit the tissues or the parts of the opposing denture which they contact. The development of the impressions and the positioning of the teeth constitute two thirds of this requirement. The anatomic contouring and finishing of the polished surfaces make up the remaining one third. Contouring of the polished surface in accordance with the functional anatomy which will be contacting these surfaces will not only improve the dentures from the standpoints of esthetics, phonetics, and comfort, but will also add to the retention and stability of dentures. 20 www.indiandentalacademy.com
  150. 150. The Mandibular Denture: The mandibular denture is generally more difficult than maxillary for the Prosthodontist to construct and for the patient to master. There are several reasons for this: (1) the mandibular denture is seated on a movable bone. (2) The available foundational area for the mandibular denture is about one third of that for the maxillary denture. (3) The perimeters of the borders of the mandibular denture are about twice as long as those of the maxillary denture. (4) The activity of the tongue, cheeks, and lips has more direct influences upon the mandibular rather than the maxillary denture www.indiandentalacademy.com
  151. 151. By properly designing the inclined planes of the denture flanges, and by not placing the lingual surfaces of the teeth lingual to the flanges, the lips, cheeks and tongue can serve to keep the denture in place rather than to dislodge it by resting on or gliding over the “shelves” of these inclined planes The buccal surfaces of the buccal flanges should face outward and upward. The flanges in the buccal vestibules should extend out over the buccal shelves and under the buccinator muscles in the cheeks. www.indiandentalacademy.com
  152. 152. The labial flanges are determined by the position of the mandibular incisors, which must be in the same place the natural teeth occupied. The contours of these flanges and the teeth must give support to the lip during function. The labial surfaces of the flanges should not be anterior to the labial surfaces of the teeth. Between the labial and buccal flanges, the flange in the buccal notch region should be narrow to allow for movements of elevating the corners of the mouth. www.indiandentalacademy.com
  153. 153. The lingual surfaces of the lingual flange should face inward and upward so that the borders lie under the tongue. Thus, the border seal can be maintained during function, and air cannot get under the denture. www.indiandentalacademy.com
  154. 154. The maxillary denture: The buccals surfaces should face outward and downward and should fill the buccal vestibules. The buccal flanges in the buccal notch regions should be sufficiently narrow to allow for the freed on of movements of the modioli and their muscle components. The labial surfaces should not be anterior to the labial surfaces of the teeth natural anatomic contours. For better speech performance and adaptability, the thickness of the palate should be uniform and as thin as practical for the type of denture base material used. However, as the palate slopes toward the alveolar ridges, the thickness will vary according to the amount of resorption. www.indiandentalacademy.com
  155. 155. Review of literature Mark A. Pigno and Jeff. J. Funk 12 – Prosthetic management of a total glossetomy defect after free flap reconstruction in an edentulous patient: A clinical report. J. Prosthet Dent. 2003, 89: 119-22 In this report they described the prosthetic treatment for an edentulous total glossectomy patient with an unconventional custom impression procedure to develop and record proper lower lip and cheek support. The patient was totally edentulous. The resection and free flap reconstruction had obliterated his mandibular ridge and buccal/lingual vestibules. The floor of his mouth was flattened with minimum bulk introduced for creation of a neotongue. The reconstruction greatly reduced his oropharyngeal opening. His lower lip collapsed back into the oral cavity, due to lack of support and traction on the lower lip originating from surgical closure ofwww.indiandentalacademy.com the defect.
  156. 156. www.indiandentalacademy.com
  157. 157. www.indiandentalacademy.com
  158. 158. David Marmor and James E. Herbertson,2 the use of swallowing in making complete denture J. Pros Den Vol 19;3: 208-18 March 1968. They described the use of complicated neuromuscular events of swallowing in making of functional mandibular impression. Anatomically and functionally, the mylohyoid muscle forms the floor of the mouth. The anterior fibers of the muscle are thin and weak, and have a low attachment below the residual ridge on the inner surface of the mandible. However, the posterior fibers are thick and strong, and may be attached to something as high as the crest of the residual ridge in the molar region. www.indiandentalacademy.com
  159. 159. These fibers, suspended from the inner surface of the mandible on both sides, form a sling to raise the tonguehyoid-larynx column. The posterior fibers of the mylohyoid muscle help raise the tongue-hyoid-larynx column and act as a curtain, which swings both inward, and upward in swallowing. The posterior part of the mylohyoid muscles and the tongue-hyoid-larynx column raise more during swallowing than during speaking. Furthermore, although talking causes upward movements similar to swallowing, these movements are not as constant as those found in swallowing. Therefore swallowing may be used as an index of the motor activity of tongue-hyoid-larynx column and the floor of the mouth. www.indiandentalacademy.com
  160. 160. Simmonds Charles R. and Philip M. Jones26 A variation in complete mandibular impression form related to an anomaly of the mylohyoid muscle, J. Pros Dent vol. 19, 3: 208-18 Mach, 1968. They did an investigative study on the prevalence of the variation in complete mandibular impression. The mylohyoid eminentiae as they termed, a protuberance or buldge that occasionally occur in the areas of the impression commonly called mylohyoid flange. This bump may extended from the location near the crest of the ridge to the lingual border of the flange about the area of the molar. www.indiandentalacademy.com
  161. 161. They concluded that the mylohyoid eminentiae occurs when a gap exists in the mylohyoid muscle. During impression making, using swallowing as a functional aid, the mylohyoid fasciculi move medially and upward. This contraction and pressure from the impression material allows the overlying mucous membrane to sag in to the aperture in the mylohyoid muscle. However, the existence may be considered clinically unimportant because they can be altered if necessary without affecting the serviceability of the denture. www.indiandentalacademy.com
  162. 162. John L. Shannon10 edentulous impression procedure for region of the mentalis muscles – Vol 26; 2:130-33,1971 He described a technique for making an impression in the region of mentalis muscles. www.indiandentalacademy.com
  163. 163. PROCEDURES 1. When the mentalis muscles are clinically evident by palpation or sight 2. A black modeling compound tray is made in the manner described by Boucher 3. The anterior portion of the modeling compound tray is examined in the region of the lingual part of the labial flange. The impression of the mentalis muscle is outlined and relieved (cut away) 1 mm. on the lingual surface of the labial flange where the impression of the mentalis muscle crossed the border. 4. The cut away part of the tray is heated with an alcohol torch, tempered, and then placed in the patient’s mouth. 5. The patient is asked to pout. This procedure will activate the mentalis muscles, the lower lip will turn outward, and the skin of the chin will be elevated. The master cast will allow fabrication of a basal denture surface which will allow for the action of the mentalis muscles The procedure is same when the mentalis muscles are not clinically evident except in this case two notches approximately 5 mm wide are carved into the lower labial flange of the modeling compound tray on either side of the midline 6 mm. apart. www.indiandentalacademy.com BACK
  164. 164. Harold W. Preiskel 8 The posterior lingual extension of complete lower dentures. J. Pros Den, Vol 19, 5: 452-59, May, 1968 Correct extension of the complete lower denture base is not only essential for the development of retentive forces to best advantage, but it is a prerequisite of maximum stability. In most regions of the oral cavity, the directions of the flanges of complete dentures are determined by the contours of the underlying bone. However, in the posterior lingual region, it is necessary to allow the mylohyoid muscle freedom of movement. Commonly, the lingual flanges rest on the mucosa overlying the mylohyoid muscles. These improperly shaped flanges cause trauma, and the denture is subjected to a displacing force whenever the patient moves his tongue or swallows. As the base may already be overextended in this region, the problem is not one of simple extension, and reduction of the flange will not help matters. The answer lies in a lingually inclined, fully extended flange, which allows for freedom of www.indiandentalacademy.com movement of the mylohyoid muscle.
  165. 165. Lawson W.A. 11 Influence of the sublingual fold on retention of complete lower denture, J. Pros Den Vol 11; 6: 1038-44 (Nov- Dec) 1961 He described The factor actually governing the position of the anterior lingual border of the lower complete denture is the sublingual fold. The denture border cannot be extended below the highest level of the mucosa in this region. However, the border can be extended horizontally backward until contact is made with the sublingual fold. www.indiandentalacademy.com
  166. 166. Thus, the seal is developed by the floor of the mouth when the tongue tip is retracted and by the sublingual fold when the tongue is relaxed in a forward position. He concluded that the size and position of sublingual folds vary considerably in different patients. Some are large and well developed, whereas others are much smaller, particularly in elderly patients in whom degenerative changes have occurred. The smaller the fold, the poorer are the chances of complete success and the greater becomes the care required to achieve the necessary contact with the mucosa of the floor ofwww.indiandentalacademy.com the mouth.
  167. 167. Barred et al 1 – structure of the mouth in the mandibular molar region and its relation to denture J. Pros Den Vol 12, 5: 835-47, 1962 They dissected on the cadaver to confirm the limiting structures for extension of the mandibular denture in the molar region and summarized as The denture rests on the residual ridges of the mucoperiosteum and mandible, with its flanges overlying the origins of the mylohyoid and buccinator muscle Posteriorly, it extends over the square and triangle and crosses the retromolar pad. www.indiandentalacademy.com
  168. 168. The yielding triangle allows a retromylohyoid extension of the denture and the pad and the construction of a small post dm, giving excellent seal Over the anterior border and alveolar crest of the mandible, the tissues are less yielding, and this is a region of critical seal The anterior edges of the masseter and medial pterygoid muscles lie on either side of this region The medial pterygoid muscle prevents any considerable extension of the denture into the constrictor square www.indiandentalacademy.com
  169. 169. Wilkinson T. M. 30 – the relationship between the disck and lateral pterygoid muscle in the human temporomandibular joint J. Prosthet. Dent. Vol 60: 715-24, 1988 As reported in this article twenty-six human cadaver temporomandibular joints were dissected to investigate the insertion of the superior and inferior heads of the lateral pterygoid muscles and the nature of the attachment of the foot of the articular disk to the roof of the superior head of the lateral pterygoid muscle. The major insertion of the superior head of the lateral pterygoid muscle is to the condyle at the pterygoid fovea. In 70% of the joints, the superior head had two insertions. The major insertion was directly to the fovea and a smaller accessory insertion, comprising the upper most 20% of the muscle, terminated under the foot of the disk. These accessory muscle fibers then blend with the anterior ligament and run posteriorly to gain insertion into the condyle. These muscle fibers then blend with the anterior ligament and run posteriorly to gain insertion into the condyle. These muscle fibers do not pass through the www.indiandentalacademy.com BACK capsule and do not insert into the disk.
  170. 170. SUMMARY When the kinetics of the orofacial muscles and those associated structure are better understood, the borders of the dentures – including the posterior palatal seal, the contours of polished surfaces and the position of the teeth are understood to internal parts of each patients oral cavity and not just mechanical artificial www.indiandentalacademy.com substitutes
  171. 171. REFERENCES 1. Barred et al – structure of the mouth in the mandibular molar region and its relation to denture J. Pros Den Vol 12, 5: 835-47, 1962 2. David Marmor and James E. Herbertson – the use of swallowing in making complete denture J. Pros Den Vol 19;3: 208-18 March 1968. 3. Dorland’s Medical Dictionary, 23rd ed. 1983 4. Douglass A. Tenry and Philip Pirtle – Learning to smile : The neuroanatomic Basis for smile training – J. Esthet. Dent. 2003, 89: 119-22 5. George A. Zarb et al Boucher’s Prosthodontics Treatment for Edentulous Patient 11th ed. 6. Gerard J. Tora Tora, Nicholas P. Anagnostakos – principles of anatomy and physiology, 6th ed. 1990 7. Grays Human Anatomy 8. Harold W. Preiskel – The posterior lingual extension of complete lower dentures. J. Pros Den, Vol 19, 5: 452-59, May, 1968 9. John F. Bowley et al – Mastication muscle activity assessment and reliability of portable electromyographic instrument, J. Prosthet Dent 2001, 85: 252-60 www.indiandentalacademy.com
  172. 172. • • • • • • • John L. Shannon – edentulous impression procedure for region of the mentalis muscles – Vol 26; 2:130-33,1971 Lawson W.A. – Influence of the sublingual fold on retention of complete lower denture, J. Pros Den Vol 11 6: 1038-44 (Nov- Dec) 1961 Mark A. Pigno and Jeff. J. Funk – Prosthetic management of a total glossetomy defect after free flap reconstruction in an edentulous patient: A clinical report. J. Prosthet Dent. 2003, 89: 119-22 Martone A. L. et al – Anatomy of the mouth and related structure, Part I, The face, J. Prostho Dent, Martone AL et al 11:1009-1018 (Nov-Dec) 1961 Martone A.L. et al - The phenomenon of function in complete denture prosthodontics; Anatomy of the mouth and related structure. Part II, Musculature of expression J. Pros Den Vol 12: 4-27 (Jan, Feb) 1962 Martone A. L. et al - The phenomenon of function in complete denture prosthodontics; Anatomy of the mouth and related structure. Part III, Functional anatomic consideration, 12:206-219 (March – April), 1962 Martone A. L. et al- The phenomenon of function in complete denture prosthodontics; Anatomy of the mouth and related structure. Part – IV physiology of speech – J. Pros Den 12: 409-19 (Maywww.indiandentalacademy.com June) 1962
  173. 173. • • • • • • • • Martone A. L. et al- The phenomenon of function in complete denture prosthodontics; Anatomy of the mouth and related structure. Part V, speech science, research of prosthodontic significance. J. Pros Den Vol 12 629-36 (July – Aug) 1964 Martone A. L. et al- The phenomenon of function in complete denture prosthodontics; Clinical application of concept of functional anatomy and speech science to complete denture prosthodontics, Part VI – The diagnostic phage – J. Pros, Den, Vol 12, 5:817-34 (Sept –Oct) 1962 Martone A. L. et al- The phenomenon of function in complete denture prosthodontics;. Clinical application of concept of functional anatomy and speech science to complete denture prosthodontics, Part VII, the recording phages - J. Pros Den vol 13; 2:204-27, 1963 Martone A. L. et al- The phenomenon of function in complete denture prosthodontics; Clinical application of concept of functional anatomy and speech science to complete denture prosthodontics, Part VIII The Final phages of denture construction, J. Pros Den Vol 13: 204-227, 1963 Martone A. L., Anatomy of facial expression and its prosthodontic significance, vol 12;6:1020-41, (Nov-Dec) 1962 Miller C. J. – The smile line as a guide to anterior esthetics – Dental clinic North America, 33: 157-164, 1989 Okeson Jeffory P. – Management of temporomandibular disorders and occlusion 5th ed. Ranh A.O. and Heartwell Jr. Text Book of complete dentures, 5th ed. 2003 ( Printed in India) www.indiandentalacademy.com
  174. 174. • Sicher and Dr Brul’s Oral anatomy – 8th ed. 1988 • Simmonds Charles R. and Philip M. Jones – A variation in complete mandibular impression form related to an anomaly of the mylohyoid muscle, J. Pros Dent vol. 19, 3: 208-18 Mach, 1968 • The Glossary of Prosthodontic Terminology – 7th ed. January 1999 • The Oxford Dictionary of difficult word, 2002 • Victor H. Sear et al – Dental Prosthesis, 2nd ed, 1962 Mosby • Wilkinson T. M. – the relationship between the disc and lateral pterygoid muscle in the human temporomandibular joint J. Prosthet. Dent. Vol 60: 71524, 1988 • Winkler Sheldon- Essential of complete denture prosthodontics, 2nd ed. 1996 (Indian 1st print) www.indiandentalacademy.com
  175. 175. THANK YOU www.indiandentalacademy.com Leader in continuing dental education www.indiandentalacademy.com

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