Log in using OpenID

Applied Anatomy and Physiology of oral Cavity

The osseous structure not only support the
denture but also have an direct bearing on
impression making procedure.
Maxillary denture is supported by two pairs of
bones, maxillae & palatine bone.
Mandibular denture is supported by one
bone, the mandible.
There are two maxillae, each consisting of
central body and four processes.
Areas of the body two of the processes are
involved in the support of maxillary denture.
Anterolateral surface of the body of the
maxilla forms the skeleton of the anterior
part of the cheek and is termed the malar
1.Labial frenum
2.Labial vestibule
3.Buccal frenum
4.Buccal vestibule
6.Crest of alveolar ridge
7.Maxillary tuberosity
8.Hamular notch
9.Hard palate
10.Fovea palatini
11.Mid-palatine raphe
12.Incisive papilla
13.Palatine rugae
:-It starts at the tip of the zygomatic process
and continues in an arc inferiorly and laterally
in the direction of first molar.
-This crest has been likened to the buccal shelf
in the mandible as a stress bearing area.
:-It is the posterior convexity of the maxillary
-The medial & lateral walls resist the horizontal
and torquing forces which would move the
denture base in lateral or palatal direction.
-Therefore, max denture base should cover the
tubercles and fill the hamular notches.
The square arch provides best form denture
:-It arises from lower surface of maxilla.
-It consists of two parallel plates of cortical
bone, buccolingual or labiolingual,which
unite behind the last molar tooth to firm the
alveolar tubercle.
:-It arises as horizontal plates from the body of
maxilla,which unite in midline ,forming
midpalatal suure
-The horizontal palatine process of maxilla
appear to resist resorption over a long
-As the bone of the aleolar ridge
resorb,pressure of the vertical forces is
increased over the bone of the palate.
When this bone become prominent in mid
palatal suture area,it becomes fulcrum point
aroud which maxillary denture base will
-This in results discomfort to the patient and
damage to soft tissue covering.
It consist of series of ridges in the anterior
part of the hard palate
It is made up of keratinized fibrous
connective tissue
It is the secondary stress bearing area
because it resist the forward movement of
It is present as a raised bony ridge along the
midline of hard palate
The mucousa is thin and non resilent
It act as fulcrum point so relieved
-Is located in the midline of the palateposterior
to the maxillary central incisors.
-Nasopalatine nerves and blood vessels make
their exit to the palate at right angles to
margins of the bony foramen.
-Denture base should be relieved over the
areato avoid pressure to the nerves & blood
The fovea palatine are indentation near he
midline of the palated form by the
coalescence of several mucous glands duct
They are closed to the vibrating line and
always in the soft palate and, an ideal guide
for the location of posterior border of denture
Vibrating line is an imaginary line across the
palate that mark the beginning of moation of
soft palate , when the pt. say ‘ahh’
it extent from one pterygo-maxilary notch
at the midline it usually passes about 2mm
in fornt of fovea palatine
The direction of the vibrating line usually
waries with the shape of palate , the higher
the wault the more abrupt and forward the
vibrating line
In mouth with flat wault the vibrating line is
usually farther posterior and has a gradual
The distal ends of the upper denture must
extent at least to the vibrating line
in most instence the denture should end 1 to
2 mm posterior to the vibrating line
when the anterior teeth are to be placed well
anterior to the residual ridge it may be
possible to extent the denture posteriorly
provided the pt can tolerate
Labia frenum
The labial frenum is a fold of mucous
membrane at the midline
It starts superiorly as fan shape and
converges as it descend to its terminal end
attachment on the labial side of ridge
It is a relief area
It is a single fold of mm sometime double and
sometimes broad and fan shaped
The caninus attaches beneath and affects its
The orbiculeris oris pulls the frenum forward
and buccinator pulls backward
Inadequate relief or thick flange can cause
dislodgement of denture when cheeks are
moved posteriorly
It extends from buccal frenum to hamular
It size varies with contraction of buccinator
,position of mandible ,amount of bone lost
from maxilla
It is a peripheral seal area
The horizontal plates of the palatine bone
articulates with the posterior rough border of
horizontal palatal process of maxilla.
The posterior border of horizontal plates of
the palatine bone unite at midline to form a
sharp line,the posterior nasal spine.
The posterior margins of hard palate serve as
the anteior attachment for the aponeurosis of
the soft palate.
The posterior palatal seal should follow the
contour of the posterior border of the hard
palate,this would extend from hamular notch
to hamular notch but not in straight line.
The major or anterior palatine foramen is
located medial to 3rd molarat the junction of
the maxilla and the horizontal plates of the
palatine bone.
The bone is notched and the palatine groove
extends anteriorly.
The nerves and blood vessels are housed in
the groove so rarely a relief is required in the
denture base over the area.
Pterygoid hamulus does not support a
maxillary denture,its position is in the
osseous limit of the maxillary denture base
posterior to the alveolar tubercle.
The pterygoid hamulus is a thin curve
process at the terminal end of the medial
plates of sphenoid bone.
A hamular notch is present between the
pterygoid hamulus and alveolar tubercle.
The body of mandible is horse shoe shaped
and carries the alveolar process.
The distal portion of each side continues
upward and backward into the mandibular
The ramus divides superiorly into the two
processes,posteriorly the condyloid and
anteriorly the coronal process.
The condyle is the articulating surface of the
condyloid process.
The connection of the condyle with the ramus
is slightly constricted called as manibular
The coronoid process is the triangular bony
plate ending in a sharp corner,the convex
anterior border continues in to the anterior
border of the ramus.
When the mandible is protruded the anterior
border of ramus extends towards the alveolar
If disto-lingual flange of the maxillary
denture overfills the vestibule,it causes
discomfort when the mandible is protruded.
The denture could be dislodged when
mandible in protrution is moved into right or
left position.
The external oblique line is the ridge of dense
bone,extending from just above mental
foramen,posteriorly and distally becoming
continuous with the anterior border of
The external oblique ridge is an anatomic
guide for the lateral terminaion of the
madibular denture.
The buccal shelf area is bounded externally
by the external oblique line and internally by
the slope of the residual ridge.
The bone is very dense and the resultant
forces of the elevator muscles directed in this
area are best resisted.
Buccal shelf area is a primary stress bearing
area due to its density mucosal covering and
its relation to the vertical closure of the jaw
are favourable to best resist the forces.
The mental foramen located on the lateral
surface of the mandible between the 1st and
2nd bicuspid
If the loss of the residual ridge is
extensive,the foramen occupies superior
position and the denture base should be
relieved over the area.
The mylohyoid line is an irregular rough bony
crest extending from the 3rd molar to the
lower border of mandible in the region of
The irregularity of the crest often presents a
problem to the denture.
The lingual flange of the mandibular denture
should extend inferior but not lateral to
mylohyoid line.
if bony crest is so prominent and sharp it
becomes the fulcrum point,surgical
intervention is indicated.
The lingual tuberosity is an irregular area of
bony prominance at the distal termination of
the mylohyoid line.
When this area s excessively prominent or
rough, it may present an undesirable
undercut area so sugically removed or
The genial tubercles or mental spines are
situated on the lingual aspect of the
mandibular body in the midline.
When the loss of residual ridge is
extensive,the spines are sometimes superior
in position than crest of ridge so surgical
procedure is implicated.
The crest of the residual alveolar ridge is
covered by favourable connective tissue but
the underlying bone is cancellous so consider
as secondary stress bearing area
It is band of fibrous connective tissue that
help attach the orbicularis oris
It is a relief area
The part of denture that extends between
labial and buccal frenum is called labial
The buccal frenum is a continous band of
through the modiolus at the corner of the
mouth to the buccal frenum in maxilla
It is a relief area
The tone of skin of lip and of orbicularis oris
depends on thickness of flange and position
of teeth
Buccal vestibule
It extends from buccal frenum posteriorly to
the outside back corner of the retro molar
pad and from crest of residual ridge to the
Masticatory Muscles
It consists of three layers which blend
The superficial layer is the largest.
It arises by a thick aponeurosis from the
maxillary process of the zygomatic bone and
from the anterior two-thirds of the inferior
border of the zygomatic arch.
Its fibres pass downwards and backwards, to
insert into the angle and lower posterior half
of the lateral surface of the mandibular
Intramuscular tendinous septa in this layer
are responsible for the ridges on the surface
of the ramus.
The middle layer of masseter arises from the
medial aspect of the anterior two-thirds of
the zygomatic arch and from the lower
border of the posterior third of this arch. It
inserts into the central part of the ramus of
the mandible.
The deep layer arises from the deep surface
of the zygomatic arch and inserts into the
upper part of the mandibular ramus and into
its coronoid process.
There is still debate as to whether fibres of
masseter are attached to the anterolateral
part of the articular disc of the
temporomandibular joint.
◦ Skin, platysma, risorius, zygomaticus major, the
parotid gland and duct, branches of the facial nerve
and the transverse facial branches of the superficial
temporal vessels are all superficial relations.
◦ Temporalis and the ramus of the mandible lie deep
to masseter.
◦ The anterior margin of masseter is separated from
buccinator and the buccal branch of the mandibular
nerve by a buccal pad of fat and crossed by the
facial vein.
◦ The posterior margin of the muscle is overlapped
by the parotid gland. The masseteric nerve and
artery reach the deep surface of masseter by
passing over the mandibular incisure (mandibular
• Vascular supply
 Masseter is supplied by the
masseteric branch of the maxillary
artery, the facial artery and the
transverse facial branch of the
superficial temporal artery.
◦ Innervation
 Masseter is supplied by the
masseteric branch of the anterior
trunk of the mandibular nerve.
◦ Actions
 Masseter elevates the mandible to
occlude the teeth in mastication and
has a small effect in side-to-side
movements, protraction and
retraction. Its electrical activity in
the resting position of the mandible
is minimal.
Temporalis arises from the whole of the
temporal fossa up to the inferior temporal
line - except the part formed by the
zygomatic bone - and from the deep surface
of the temporal fascia.
Its fibres converge and descend into a tendon
which passes through the gap between the
zygomatic arch and the side of the skull.
The muscle is attached to the medial surface,
apex, anterior and posterior borders of the
coronoid process and to the anterior border
of the mandibular ramus almost up to the
third molar tooth.
The anterior fibres of temporalis are
orientated vertically, the most posterior fibres
almost horizontally, and the intervening
fibres with intermediate degrees of obliquity,
in the manner of a fan.
Fibres of temporalis may occasionally gain
attachment to the articular disc.
Relations:Body Skin, auriculares anterior and superior,
temporal fascia, superficial temporal vessels,
the auriculotemporal nerve, temporal
branches of the facial nerve, the
zygomaticotemporal nerve, the epicranial
aponeurosis, the zygomatic arch and the
masseter muscle are all superficial relations.
Posterior relations of temporalis are the
temporal fossa above and the major
components of the infratemporal fossa
below. Behind the tendon of the muscle, the
masseteric nerve and vessels traverse the
mandibular notch.
The anterior border is separated from the
zygomatic bone by a mass of fat
Vascular supply:Temporalis is supplied by the deep temporal
branches from the second part of the
maxillary artery.
The anterior deep temporal artery supplies
c.20% of the muscle anteriorly, the posterior
deep temporal supplies c.40% of the muscle
in the posterior region and the middle
temporal artery supplies c.40% of the muscle
in its mid-region.
Body Innervation : Temporalis is supplied by the deep
temporal branches of the anterior trunk
of the mandibular nerve.
Actions:Temporalis elevates the mandible and so closes
the mouth and approximates the teeth. This
movement requires both the upward pull of the
anterior fibres and the backward pull of the
posterior fibres, because the head of the
mandibular condyle rests on the articular
eminence when the mouth is open.
The muscle also contributes to side-to-side
grinding movements. The posterior fibres retract
the mandible after it has been protruded.
Lateral pterygoid :is a short, thick muscle consisting of two
parts.--The upper head arises from the
infratemporal surface and infratemporal crest
of the greater wing of the sphenoid bone.
The lower head arises from the lateral surface
of the lateral pterygoid plate.
Vascular supply
Lateral pterygoid is supplied by pterygoid
branches from the maxillary artery which are
given off as the artery crosses the muscle and
from the ascending palatine branch of the
facial artery.
The nerves to lateral pterygoid (one for each
head) arise from the anterior trunk of the
mandibular nerve, deep to the muscle.
The upper head and the lateral part of the
lower head receive their innervation from a
branch given off from the buccal nerve.
However, the medial part of the lower head
has a branch arising directly from the anterior
trunk of the mandibular nerve.
From the two origins, the fibres converge,
and pass backwards and laterally, to be
inserted into a depression on the front of the
neck of the mandible (the pterygoid fovea).
A part of the upper head may be attached to
the capsule of the temporomandibular joint
and to the anterior and medial borders of its
articular disc.
Actions :When left and right muscles contract together
the condyle is pulled forward and slightly
This protrusive movement alone has little or
no function except to assist opening the jaw.
If only one lateral pterygoid contracts, the jaw
rotates about a vertical axis passing roughly
through the opposite condyle and is pulled
medially toward the opposite side.
This contraction together with that of the
adjacent medial pterygoid (both attached to the
lateral pterygoid plate) provides most of the
strong medially directed component of the force
used when grinding food between teeth of the
same side.
It is arguably the most important function of
the inferior head of lateral pterygoid.
It is often stated that the upper head is used
to pull the articular disc forward when the jaw
is opene
This contraction together with that of the adjacent medial
pterygoid (both attached to the lateral pterygoid plate)
provides most of the strong medially directed component
of the force used when grinding food between teeth of the
same side. It is arguably the most important function of
the inferior head of lateral pterygoid.
It is often stated that the upper head is used to pull the
articular disc forward when the jaw is opened.
Most of the power of a clenching force is due to
contractions of masseter and temporalis. The associated
backward pull of temporalis is greater than the associated
forward pull of (superficial) masseter, and so their
combined jaw closing action potentially pulls the condyle
backward. This is prevented by the simultaneous
Medial pterygoid :is a thick, quadrilateral muscle with two
heads of origin. The major component is the
deep head which arises from the medial
surface of the lateral pterygoid plate of the
sphenoid bone and is therefore deep to the
lower head of lateral pterygoid.
The small, superficial head arises from the
maxillary tuberosity and the pyramidal
process of the palatine bone, and therefore
lies on the lower head of lateral pterygoid.
The fibres of medial pterygoid descend
posterolaterally and are attached by a strong
tendinous lamina to the posteroinferior part
of the medial surface of the ramus and angle
of the mandible, as high as the mandibular
foramen and almost as far forwards as the
mylohyoid groove. This area of attachment is
often ridged.
The lateral surface of medial pterygoid is
related to the mandibular ramus, from which
it is separated above its insertion by lateral
pterygoid, the sphenomandibular ligament,
the maxillary artery, the inferior alveolar
vessels and nerve, the lingual nerve and a
process of the parotid gland.
The medial surface is related to tensor veli
palatini and is separated from the superior
pharyngeal constrictor by styloglossus and
stylopharyngeus and by some areolar tissue.
Vascular supply
Medial pterygoid derives its main arterial
supply from the pterygoid branches of the
maxillary artery.
Medial pterygoid is innervated by the medial
pterygoid branch of the mandibular nerve.
The medial pterygoid muscles assist in elevating
the mandible. Acting with the lateral pterygoids
they protrude it.
When the medial and lateral pterygoids of one
side act together, the corresponding side of the
mandible is rotated forwards and to the opposite
side, with the opposite mandibular head as a
vertical axis.
Alternating activity in the left and right sets of
muscles produces side-to-side movements,
which are used to triturate food.
Pterygospinous ligament .The pterygospinous
ligament, which is occasionally replaced by
muscle fibres, stretches between the spine of
the sphenoid bone and the posterior border
of the lateral pterygoid plate near its upper
end. It is sometimes ossified, and then
completes a foramen which transmits the
branches of the mandibular nerve to
temporalis, masseter and lateral pterygoid
The superior constrictor is a quadrilateral sheet of
muscle and is thinner than the other two constrictors.
It is attached anteriorly to the pterygoid hamulus (and
sometimes to the adjoining posterior margin of the
medial pterygoid plate), the posterior border of the
pterygomandibular raphe, the posterior end of the
mylohyoid line of the mandible, and, by a few fibres,
to the side of the tongue.
The fibres curve back into a median pharyngeal raphe
which is attached superiorly to the pharyngeal
tubercle on the basilar part of the occipital bone
The fibres curve back into a median
pharyngeal raphe which is attached superiorly
to the pharyngeal tubercle on the basilar part
of the occipital bone
The upper border of the superior constrictor
is separated from the cranial base by a
crescentic interval which contains levator veli
palatini, the pharyngotympanic tube and an
upward projection of pharyngobasilar fascia.
The lower border is separated from the
middle constrictor by stylopharyngeus and
the glossopharyngeal nerve
Anteriorly the pterygomandibular raphe separates
the superior constrictor from buccinator, and
posteriorly the superior constrictor lies on the
prevertebral muscles and fascia, from which it is
separated by the retropharyngeal space.
The ascending pharyngeal artery, pharyngeal
venous plexus, glossopharyngeal and lingual
nerves, styloglossus, middle constrictor, medial
pterygoid, stylopharyngeus, and the stylohyoid
ligament all lie laterally, and palatopharyngeus, the
tonsillar capsule and the pharyngobasilar fascia lie
Vascular supply.
The arterial supply of the superior
constrictor is derived mainly from the
pharyngeal branch of the ascending
pharyngeal artery and the tonsillar branch of
the facial artery.
The superior constrictor is innervated by the
cranial part of the accessory nerve from the
pharyngeal plexus.
The superior constrictor constricts the upper
part of the pharynx.
The tongue is divided by a median fibrous
septum, attached to the body of the hyoid
There are extrinsic and intrinsic muscles in
each half, the former extending outside the
tongue and moving it bodily, the latter wholly
within it and altering its shape.
The extrinsic musculature consists of four
pairs of muscles namely genioglossus,
hyoglossus, styloglossus (and
chondroglossus) and palatoglossus.
The intrinsic muscles are the bilateral
superior and inferior longitudinal, the
transverse and the vertical.
Genioglossus is triangular in sagittal section,
lying near and parallel to the midline. It arises
from a short tendon attached to the superior
genial tubercle behind the mandibular
symphysis, above the origin of geniohyoid. From
this point it fans out backwards and upwards.
The inferior fibres of genioglossus are attached
by a thin aponeurosis to the upper anterior
surface of the hyoid body near the midline (a few
fasciculi passing between hyoglossus and
chondroglossus to blend with the middle
constrictor of the pharynx).
Intermediate fibres pass backwards into the
posterior part of the tongue, and superior
fibres ascend forwards to enter the whole
length of the ventral surface of the tongue
from root to apex, intermingling with the
intrinsic muscles.
The muscles of opposite sides are separated
posteriorly by the lingual septum.
Vascular supply
Genioglossus is supplied by the sublingual
branch of the lingual artery and the
submental branch of the facial artery.
Genioglossus is innervated by the
hypoglossal nerve.
Genioglossus brings about the forward
traction of the tongue to protrude its apex
from the mouth.
Acting bilaterally, the two muscles depress
the central part of the tongue, making it
concave from side to side.
Acting unilaterally, the tongue diverges to
the opposite side
Hyoglossus (
Hyoglossus is thin and quadrilateral, and
arises from the whole length of the greater
cornu and the front of the body of the hyoid
It passes vertically up to enter the side of the
tongue between styloglossus laterally and the
inferior longitudinal muscle medially. Fibres
arising from the body of the hyoid overlap
those from the greater cornu.
Hyoglossus is related at its superficial surface to
the digastric tendon, stylohyoid, styloglossus and
mylohyoid, the lingual nerve and submandibular
ganglion, the sublingual gland, the deep part of
the submandibular gland and duct, the
hypoglossal nerve and the deep lingual vein.
By its deep surface it is related to the stylohyoid
ligament, genioglossus, the middle constrictor
and the inferior longitudinal muscle of the
tongue, and the glossopharyngeal nerve.
Posteroinferiorly it is separated from the
middle constrictor by the lingual artery. This
part of the muscle is in the lateral wall of the
pharynx, below the palatine tonsil. Passing
deep to the posterior border of hyoglossus
are, in descending order: the
glossopharyngeal nerve, stylohyoid ligament
and lingual artery
Vascular supply
Hyoglossus is supplied by the sublingual
branch of the lingual artery and the
submental branch of the facial artery.
Hyoglossus is innervated by the hypoglossal
Hyoglossus depresses the tongue.
Styloglossus is the shortest and smallest of
the three styloid muscles.
It arises from the anterolateral aspect of the
styloid process near its apex, and from the
styloid end of the stylomandibular ligament.
Passing downwards and forwards, it divides
at the side of the tongue into a longitudinal
part, which enters the tongue dorsolaterally
to blend with the inferior longitudinal muscle
in front of hyoglossus, and an oblique part,
overlapping hyoglossus and decussating with
Vascular supply
Styloglossus is supplied by the sublingual
branch of the lingual artery.
Styloglossus is innervated by the hypoglossal
Styloglossus draws the tongue up and
Intrinsic muscles
Superior longitudinal
The superior longitudinal muscle constitutes a
thin stratum of oblique and longitudinal fibres
lying beneath the mucosa of the dorsum of the
It extends forwards from the submucous fibrous
tissue near the epiglottis and from the median
lingual septum to the lingual margins.
Some fibres are inserted into the mucous
Inferior longitudinal
The inferior longitudinal muscle is a narrow
band of muscle close to the inferior lingual
surface between genioglossus and
hyoglossus. It extends from the root of the
tongue to the apex.
Some of its posterior fibres are connected to
the body of the hyoid bone. Anteriorly it
blends with styloglossus.
The transverse muscles pass laterally from
the median fibrous septum to the submucous
fibrous tissue at the lingual margin, blending
with palatopharyngeus.
The vertical muscles extend from the dorsal
to the ventral aspects of the tongue in the
anterior borders
Vascular supply
The intrinsic muscles are supplied by the
lingual artery.
All intrinsic lingual muscles are innervated by
the hypoglossal nerve.
The intrinsic muscles alter the shape of the
tongue. Thus, contraction of the superior and
inferior longitudinal muscles tend to shorten
the tongue, but the former also turns the
apex and sides upwards to make the dorsum
concave, while the latter pulls the apex down
to make the dorsum convex.
The transverse muscle narrows and elongates
the tongue while the vertical muscle makes it
flatter and wider. Acting alone or in pairs and
in endless combination, the intrinsic muscles
give the tongue precise and highly varied
mobility, important not only in alimentary
function but also in speech.
The soft palate is a mobile flap suspended from
the posterior border of the hard palate, sloping
down and back between the oral and nasal parts
of the pharynx.
The boundary between the hard and soft palate
is readily palpable and may be distinguished by a
change in colour, the soft palate being a darker
red with a yellowish tint.
The soft palate is a thick fold of mucosa
enclosing an aponeurosis, muscular tissue,
vessels, nerves, lymphoid tissue and mucous
In most individuals two small pits, the fovea
palatini, one on each side of the midline, may be
seen: they represent the orifices of ducts from
some of the minor mucous glands of the palate.
The anterior third of the soft palate contains little
muscle and consists mainly of the palatine
This region is less mobile and more horizontal
than the rest of the soft palate and is the chief
area acted upon by tensor veli palatini.
A small bony prominence, produced by the
pterygoid hamulus, can be felt just behind
and medial to each upper alveolar process, in
the lateral part of the anterior region of the
soft palate.
The pterygomandibular raphe –
a tendinous band between buccinator and the
superior constrictor - passes downwards and
outwards from the hamulus to the posterior
end of the mylohyoid line.
When the mouth is opened wide, this raphe
raises a fold of mucosa that marks internally
the posterior boundary of the cheek, and is
an important landmark for an inferior alveolar
nerve block.
Palatine aponeurosis
A thin, fibrous, palatine aponeurosis
strengthens the soft palate, and is composed
of the expanded tendons of the tensor veli
palatini muscles.
It is attached to the posterior border and
inferior surface of the hard palate behind any
palatine crests, and extends medially from
behind the greater palatine foramina.
It is thick in the anterior two-thirds of the
soft palate but very thin further back.
Near the midline it encloses the musculus
All the other palatine muscles are attached to
the aponeurosis.
The lateral wall of the oropharynx presents
two prominent folds, the pillars of the fauces.
The anterior fold, or palatoglossal arch, runs
from the soft palate to the side of the tongue
and contains palatoglossus.
The posterior fold, or palatopharyngeal arch,
projects more medially and passes from the
soft palate to merge with the lateral wall of
the pharynx. It contains palatopharyngeus.
A triangular tonsillar fossa (tonsillar sinus)
lies on each side of the oropharynx between
the diverging palatopharyngeal and
palatoglossal arches, and contains the
palatine tonsil
The hard palate is formed by the palatine
processes of the maxillae and the horizontal
plates of the palatine bones.
The hard palate is bounded in front and at
the sides by the tooth-bearing alveolus of the
upper jaw and is continuous posteriorly with
the soft palate.
It is covered by a thick mucosa bound tightly
to the underlying periosteum.
In its more lateral regions it also possesses a
submucosa containing the main neurovascular
The mucosa is covered by keratinized stratified
squamous epithelium which shows regional
variations and may be ortho- or parakeratinized.
The periphery of the hard palate consists of
A narrow ridge, the palatine raphe, devoid of
submucosa, runs anteroposteriorly in the
An oval prominence, the incisive papilla, lies
at the anterior extremity of the raphe and
covers the incisive fossa at the oral opening
of the incisive canal. It also marks the
position of the fetal nasopalatine canal.
Irregular transverse ridges or rugae, each
containing a core of dense connective tissue,
radiate outwards from the palatine raphe in
the anterior half of the hard palate: their
pattern is unique.
The submucosa in the posterior half of the hard
palate contains minor salivary glands of the mucous
These secrete through numerous small ducts,
although bilaterally a larger duct collecting from
many of these glands often opens at the paired
palatine foveae.
These depressions, sometimes a few millimetres
deep, flank the midline raphe at the posterior border
of the hard palate. They provide a useful landmark
for the extent of an upper denture.
The upper surface of the hard palate is the floor of
the nasal cavity and is covered by ciliated respiratory
Orbicularis oculi
Orbicularis oculi is a broad, flat, elliptical
muscle which surrounds the circumference of
the orbit and spreads into the adjacent
regions of the eyelids, anterior temporal
region, infraorbital cheek and superciliary
It has orbital, palpebral and lacrimal parts.
The orbital part arises from the nasal
component of the frontal bone, the frontal
process of the maxilla and from the medial
palpebral ligament.
The fibres form complete ellipses, without
interruption on the lateral side, where there is
no bony attachment.
The upper orbital fibres blend with the frontal
part of occipitofrontalis and the corrugator
Many of them are inserted into the skin and
subcutaneous tissue of the eyebrow, constituting
depressor supercilii.
Inferiorly and medially, the ellipses overlap or
blend to some extent with adjacent muscles
(levator labii superioris alaeque nasi, levator labii
superioris and zygomaticus minor).
At the extreme periphery, sectors of complete,
and sometimes incomplete, ellipses have a loose
areolar connection with the temporal extension
of the epicranial aponeurosis.
The palpebral part arises from the medial
palpebral ligament, mainly from its superficial
surface, and from the bone immediately
above and below the ligament.
The fibres sweep across the eyelids anterior
to the orbital septum, interlacing at the
lateral commissure to form the lateral
palpebral raphe.
A small group of fine fibres, close to the
margin of each eyelid behind the eyelashes,
constitutes the ciliary bundle.
The lacrimal part arises from the upper part
of the lacrimal crest, and the adjacent lateral
surface, of the lacrimal bone. It passes
laterally behind the nasolacrimal sac (where
some fibres are inserted into the associated
fascia), and divides into upper and lower
Some fibres are inserted into the tarsi of the
eyelids close to the lacrimal canaliculi, but
most continue across in front of the tarsi and
interlace in the lateral palpebral raphe.
Vascular supply
Orbicularis oculi is supplied by branches of
the facial, superficial temporal, maxillary and
ophthalmic arteries.
Orbicularis oculi is supplied by temporal and
zygomatic branches of the facial nerve.
Contraction of the upper orbital fibres
produces vertical furrowing above the bridge
of the nose, narrowing of the palpebral
fissure, and bunching and protrusion of the
eyebrows, which reduces the amount of light
entering the eyes.
Eye closure is largely affected by lowering of
the upper eyelid, but there is also
considerable elevation of the lower eyelid.
The palpebral portion can be contracted
voluntarily, to close the lids gently as in
sleep, or reflexly, to close the lids protectively
in blinking.
The palpebral part has upper depressor and
lower elevator fascicles.
The lacrimal part of the muscle draws the
eyelids and the lacrimal papillae medially,
exerting traction on the lacrimal fascia and
may aid drainage of tears by dilating the
lacrimal sac.
It may also influence pressure gradients
within the lacrimal gland and ducts.
When the entire orbicularis oculi muscle
contracts, the skin is thrown into folds which
radiate from the lateral angle of the eyelids.
Such folds, when permanent, cause wrinkles
in middle age (the so-called 'crow's feet').
The muscle of the cheek, buccinator, is a thin
quadrilateral muscle which occupies the interval
between the maxilla and the mandible.
Its upper and lower boundaries are attached
respectively to the outer surfaces of the alveolar
processes of the maxilla and mandible opposite
the molar teeth.
Its posterior border is attached to the anterior
margin of the pterygomandibular raphe.
In addition, a few fibres spring from a fine
tendinous band that bridges the interval between
the maxilla and the pterygoid hamulus, between
the tuberosity of the maxilla and the upper end
of the pterygomandibular raphe.
The posterior part of buccinator is deeply placed,
internal to the mandibular ramus and in the
plane of the medial pterygoid plate.
Its anterior component curves out behind the
third molar tooth to lie in the submucosa of the
cheek and lips.
The fibres of buccinator converge towards the
modiolus near the angle of the mouth. Here the
central (pterygomandibular) fibres intersect,
those from below crossing to the upper part of
orbicularis oris, and those from above crossing
to the lower part.
The highest (maxillary) and lowest (mandibULar)
fibres of buccinator continue forward to enter
their corresponding lips without decussation.
As buccinator courses through the cheek and
modiolus substantial numbers of its fibres are
diverted internally to attach to submucosa
Posteriorly, buccinator lies in the same plane as
the superior pharyngeal constrictor, which arises
from the posterior margin of the
pterygomandibular raphe, and is covered there
by the buccopharyngeal fascia.
Superficially, the buccal pad of fat separates the
posterior part of buccinator from the ramus of
the mandible, masseter and part of temporalis.
Anteriorly, the superficial surface of buccinator is
related to zygomaticus major, risorius, levator
and depressor anguli oris, and the parotid duct.
It is crossed by the facial artery, facial vein
and branches of the facial and buccal nerves.
The deep surface of buccinator is related to
the buccal glands and mucous membrane of
the mouth.
The parotid duct pierces buccinator opposite
the third upper molar tooth, and lies on the
deep surface of the muscle before opening
into the mouth opposite the maxillary second
molar tooth.
Vascular supply
Buccinator is supplied by branches from the
facial artery and the buccal branch of the
maxillary artery.
Buccinator is supplied by the buccal branch
of the facial nerve.
Buccinator compresses the cheek against the
teeth and gums during mastication, and
assists the tongue in directing food between
the teeth.
As the mouth closes, the teeth glide over the
buccolabial mucosa, which must be retracted
progressively from their occlusal surfaces by
buccinator and other submucosally attached
When the cheeks have been distended with
air, the buccinators expel it between the lips,
an activity important when playing wind
instruments, accounting for the name of the
muscle (Latin buccinator = trumpeter).
when the massetor is activated is pushes the
buccinator medialy against rhe denture in the
area of he retromolar pad
This is adislodging force and the dunture
base should be contoured to accommodate
the action
Mentalis is a conical fasciculus lying at the
side of the frenulum of the lower lip.
The fibres arise from the incisive fossa of the
mandible and descend to attach to the skin of
the chin.
Vascular supply
Mentalis is supplied by the inferior labial
branch of the facial artery and the mental
branch of the maxillary artery.
Mentalis is innervated by the mandibular
branch of the facial nerve.
Mentalis raises the lower lip, wrinkling the
skin of the chin.
Since it raises the base of the lower lip, it
helps in protruding and everting the lower lip
in drinking and also in expressing doubt or
The contraction of this muscle is capable of
dislodging a mandibular denture particularly
when the residual ridge in anterior region is
Levator anguli oris
Levator anguli oris arises from the canine
fossa of the maxilla, just below the
infraorbital foramen and inserts into and
below the angle of the mouth.
Its fibres mingle there with other muscle
fibres (zygomaticus major, depressor anguli
oris, orbicularis oris).
Some superficial fibres curve anteriorly and
attach to the dermal floor of the lower part of
the nasolabial furrow.
The infraorbital nerve and accompanying
vessels enter the face via the infraorbital
foramen between the origins of levator anguli
oris and levator labii superioris.
Vascular supply
Levator anguli oris is supplied by the
superior labial branch of the facial artery and
the infraorbital branch of the maxillary artery.
Levator anguli oris is innervated by the
zygomatic and buccal branches of the facial
Levator anguli oris raises the angle of the
mouth in smiling, and contributes to the
depth and contour of the nasolabial furrow.
Zygomaticus major
Zygomaticus major arises from the
zygomatic bone, just in front of the
zygomaticotemporal suture, and passes to
the angle of the mouth where it blends with
the fibres of levator anguli oris, orbicularis
oris and more deeply placed muscular bands.
Vascular supply
Zygomaticus major is supplied by the
superior labial branch of the facial artery.
Zygomaticus major is innervated by the
zygomatic and buccal branches of the facial
Zygomaticus major draws the angle of the
mouth upwards and laterally as in laughing.
Zygomaticus minor
Zygomaticus minor arises from the lateral
surface of the zygomatic bone immediately
behind the zygomaticomaxillary suture, and
passes downwards and medially into the
muscular substance of the upper lip.
Superiorly it is separated from levator labii
superioris by a narrow triangular interval, and
inferiorly it blends with this muscle.
Vascular supply
Zygomaticus minor is supplied by the
superior labial branch of the facial artery.
Zygomaticus minor is innervated by the
zygomatic and buccal branches of the facial
Zygomaticus minor elevates the upper lip,
exposing the maxillary teeth. It also assists in
deepening and elevating the nasolabial
Acting together, the main elevators of the lip
- levator labii superioris alaequae nasi,
levator labii superioris and zygomaticus
minor - curl the upper lip in smiling, and in
expressing smugness, contempt or disdain.
Depressor anguli oris
Depressor anguli oris has a long, linear
origin from the mental tubercle of the
mandible and its continuation, the oblique
line, below and lateral to depressor labii
It converges into a narrow fasciculus that
blends at the angle of the mouth with
orbicularis oris and risorius.
Some fibres continue into the levator anguli
oris muscle. Depressor anguli oris is
continuous below with platysma and cervical
Some of its fibres may pass below the mental
tubercle and cross the midline to interlace
with their contralateral fellows; these
constitute the transversus menti (the 'mental
Vascular supply
Depressor anguli oris is supplied by the
inferior labial branch of the facial artery and
the mental branch of the maxillary artery.
Depressor anguli oris is innervated by the
buccal and mandibular branches of the facial
Depressor anguli oris draws the angle of the
mouth downwards and laterally in opening
the mouth and in expressing sadness.
During opening of the mouth the
mentolabial sulcus becomes more horizontal
and its central part deeper.
Incisivus labii superioris
Incisivus labii superioris has a bony origin from
the floor of the incisive fossa of the maxilla
above the eminence of the lateral incisor tooth.
Initially it lies deep to orbicularis oris pars
peripheralis superior. Arching laterally, its fibre
bundles become intercalated between, and
parallel to, the orbicular bundles.
Approaching the modiolus, it segregates into
superficial and deep parts: the former blends
partially with levator anguli oris and attaches to
the body and apex of the modiolus and the latter
is attached to the superior cornu and base of the
Incisive labii inferioris
Incisivus labii inferioris, an accessory muscle of the
orbicularis oris muscle complex, has many features in
common with incisivus labii superioris.
Its osseous attachment is to the floor of the incisive
fossa of the mandible, lateral to mentalis and below
the eminence of the lateral incisor tooth.
Curving laterally and upwards, it blends to some
extent with orbicularis oris pars peripheralis inferior
before reaching the modiolus, where superficial
bundles attach to the apex and body, and deep
bundles attach to the base and inferior cornu.
The action of muscle of facial expression is
responsible for the facial posture associated
with the smiling laughing frowning or
if the muscle of facial expression are not
properly supported b y natural teeth or
artificial subsitute none of the facial
expression appear normal
Incorrectly position teeth or incorrectly
conture border base will destroy the normal
tonacity of muscle
Platysma is described as a muscle of the neck
but it is considered here as a contributor to the
orbicularis oris muscle complex.
The pars mandibularis attaches to the lower
border of the body of the mandible.
Posterior to this attachment, a substantial
flattened bundle separates and passes
superomedially to the lateral border of depressor
anguli oris, where a few fibres join this muscle.
The remainder continue deep to depressor anguli
oris and reappear at its medial border.
Here they continue within the tissue of the
lateral half of the lower lip, as a direct labial
tractor, platysma pars labialis.
Pars labialis occupies the interval between
depressor anguli oris and depressor labii
inferioris and is in the same plane as these
The adjacent margins of all three muscles blend
and they have similar labial attachments.
Platysma pars modiolaris constitutes all the
remaining bundles posterior to pars labialis,
other than a few fine fascicles that end
directly in buccal dermis or submucosa.
Pars modiolaris is posterolateral to depressor
anguli oris and passes superomedially, deep
to risorius, to apical and subapical modiolar
Mylohyoid lies superior to the anterior belly
of digastric and, with its contralateral fellow,
forms a muscular floor for the oral cavity.
It is a flat, triangular sheet attached to the
whole length of the mylohyoid line of the
mandible. The posterior fibres pass medially
and slightly downwards to the front of the
body of the hyoid bone near its lower border.
The middle and anterior fibres from each side
decussate in a median fibrous raphe that
stretches from the symphysis menti to the
hyoid bone.
The median raphe is sometimes absent, in
which case the two muscles form a
continuous sheet, or it may be fused with the
anterior belly of digastric.
In about one-third of subjects there is a
hiatus in the muscle through which a process
of the sublingual gland protrudes.
The inferior (external) surface is related to
platysma, anterior belly of digastric, the
superficial part of the submandibular gland, the
facial and submental vessels, and the mylohyoid
vessels and nerve.
The superior (internal) surface is related to
geniohyoid, part of hyoglossus and styloglossus,
the hypoglossal and lingual nerves, the
submandibular ganglion, the sublingual gland,
the deep part of the submandibular gland and its
duct, the lingual and sublingual vessels and,
posteriorly, the mucous membrane of the mouth.
Vascular supply
Mylohyoid receives its arterial supply from
the sublingual branch of the lingual artery,
the maxillary artery, via the mylohyoid branch
of the inferior alveolar artery, and the
submental branch of the facial artery.
MYlohyoid is supplied by the mylohyoid
branch of the inferior alveolar nerve.
Mylohyoid elevates the floor of the mouth in
the first stage o f deglutition
It may also elevate the hyoid bone or depress
the mandible.
Geniohyoid is a narrow muscle which lies
above the medial part of mylohyoid.
It arises from the inferior mental spine
(genial tubercle) on the back of the symphysis
menti, and runs backwards and slightly
downwards to attach to the anterior surface
of the body of the hyoid bone.
The paired muscles are contiguous and may
occasionally fuse with each other or with
Vascular supply
The blood supply to geniohyoid is derived
from the lingual artery (sublingual branch).
Geniohyoid is supplied by the first cervical
spinal nerve, through the hypoglossal nerve.
Geniohyoid elevates the hyoid bone and
draws it forwards, and therefore acts partly as
an antagonist to stylohyoid.
When the hyoid bone is fixed, geniohyoid
depresses the mandible.
Maxillary arch
The mucous membrane is composed of two
layer mucousa and submucous
The mucousal covering of the gingiva and
hard palate have common epitheliun that is
thick and hornified
The two areas may vary in their submocousa
There is no well differentiated submucusa
layer in the gingiva ,inellastic connective
tissue of the lamina propria fuses with the
periosteum the alveolar process
The mm covering the crest of alveolar ridge
isfirmly attached to periosteum of bone
The stratified squamous epitheliun is thickly
The submucousa is devoid of fat or glandular
The outer surface of bone is compact in
This compact nature with tightly attached mm
makes the crest of ridge best able to provide
primary support to denture
As the mm moves along slope of ridge it
tends to lose its firm attachment to bone and
epithelium is non keratinized or slightly
There is distinct submucousal layer in the
covering of palate
The mucous membrane is tightly attached to
the periosteum of the maxillary and palatine
The submucousa is divided into three spaces
,middle third of hard palate is filled with
adipose tissue , posterior third contains
So tissues are recorded in resting condition
because when they are displaced in final
impression they tend to return their normal
position form within the complete denture
base creating soreness
The submucosa is extremely thin in the
region of mid palatine and mucosa is
practically in contact with bone
So soft tissue covering mid palatine region is
non resilient and relief is required in this area
during final impression
In the fornix vestibule and the sublingual
sulcus the mucous membrane is loosely and
movably attached to the deep structure
The mm has thin epithelium that is non
These areas are easily displaced and act as
excellent areas to create seal for the denture
The submucosa in the region of vibrating line
contains glandular tissue
The submucosa in hamular notcn region is
thick and made up of areolar tissue
Additional pressure can be placed on tissue
in the centre of notch to create the peripheral
The mm covering the crest of residual ridge is
similar to that of maxillary ridge but
underlying bone is cancellous in nature
The mm covering the buccal shelf area is
loosely attached and less keratinized and
contains thick submucosal layer
The bone is compact in nature
In the mandibular arch the distal end is well
After the loss of last molar ,the retromolar
papilla remains attached to scar
This area is firm ,and pale and easily
distinguished from the retromolar pad, which
is soft dark red and readily displaced
The mucosa is thin and non keratinized in
retro molar region
The submucosa has loose aerolar tissue ,
glandular tissue , fibre of buccinator and
superior constrictor, pteryomandibular raphe
, tendon of temporalis
The mm lining the vestibular space and
alveololingual sulcus is similar to lining of
vestibular space of maxilla
the epithelium is thin and non keratinized
and submucosa is formed by loosely arranged
connective tissue fibre mixed with elastic
The making of impressions recording and
verifying of jaw relations ,harmoning of
occlusion of the teeth to coincide with the jaw
movements are greatly influenced by the
quality and quantity of soft tissues
Hanau has demonstrated the mucosa
supporting the denture bases is displaceable
and compressible
Some of the finding are
The tissue un the elderly take many hour to
recover from the effect of moderate
mechanical force where as youngs need only
a short time for complete recovery
The thicker the tissue the more is deformity
The sex of the individual does not affect the
Small forces can produce distinct
compression of the tissue
Light load of long duration of time deform
tissue more than heavy load of short duration
When this knowledge is applied in complete
denture prosthodontics , several factor
dentures particularly for pt. over 25 yr of
age should be removed when making
impression for new denture for sufficient
time for tissue recovery this may be 24 hr
for younger pt and several days for geriatric
a low viscosity impression material which
will flow freely after the impression material
is seated should be used, pressure is release
after seating
3. Impression material should not be confined
when making the refined impression, escaped
holes should be provided
4. An impression should not be removed and
inserted any more repeatedly than necessary
5. para-function habit produce light load for
long duration , physiologic practices occur as
heavy load short duration
6. It is responsibility of the dentist to recognize
the problem and institute procedure to
correct the source
7. Excessively thick mucosa should be
evaluated for possible surgical reduction
The presence of fatty tissue provide a
cushioned type of support ,so hard palate is
primary stress bearing area
The residual alveolar ridge is covered by
tissue which in its structure is identical with
attached gingiva
It is a firm , thick layer of inelastic ,dense
connective tissue ,immovabily attached to
The mucous membrane that comes in contact
with the denture border is thin nonhornified
epithelium and thin lamina propria
The submucosal structure may be either
tightly or loosely attached
On the lips ,cheeks ,and under side of the
tongue the lining mucosa is fixed to the
epimysium or the fascia of the muscle
Types of saliva
Serrous (thin and watery)
Mucous (thick,lucid and adhesive)
Saliva is considered a major factor in
evaluating the physical influences that
contribute to denture retention
 The physical forces in which saliva is involved
4)Atmospheric pressure
Adhesion is the binding force exerted by the
molecules of the unlike substances in
Cohesion is that force by which molecules of
the same body or same kind are held
Capillarity is the form or surface tension
between the molecules of a liquid and those
of solid.
Increasing or reducing the surrounding
pressure and temperature influences the
retention of denture because the capillary
forces affected.
physiologic factors:Agreeable taste stimuli result in profuse
salivaton,distasteful stimulus result in
temporary cessation.
A smooth object inserted into the mouth
increases salivation so denture surface should
be smooth,a rough object inhibit salivation.
When a person is dehydrated salivation
Pathologic conditions that decreases
salivation are:Sennile atrophy of salivary gland.
Radiation therapy of head and neck tumours.
Diseases of brain stem that directly depresses
salivary nucleous.
Diabetic mellitus.
Diarrhea caused by bacteria or food.
Elevated temperature.
Vitamin deficiencies.
Pathologic conditions causing increased
salivation:Digestive tract irritants.
Painfull afflictions of oral cavity.
 None Each joint involves the articular
fossa (also known as the mandibular
fossa or glenoid fossa) above and the
mandibular condyle below
 It is probably impossible to measure
the pressure developed on the
articular surfaces of the human jaw
joint when biting. There is, however,
irrefutable theoretical evidence based
on Newtonian mechanics that the jaw
forms most of the articular surface of the
articular fossa.
Its steepness is variable, and it becomes
flatter in the edentulous.
Its anterior limit is the summit of the
articular eminence, a transverse ridge that
extends laterally out to the zygomatic arch
as far as the articular tubercle.
Articular tissue extends anteriorly beyond
the articular summit and on to the
preglenoid plane.
Posteriorly it extends behind the depth of
the fossa as far as the squamotympanic
A postglenoid tubercle (at the root of the
zygomatic arch, just anterior to the fissure)
is usually poorly developed in human skulls.
The articular surface of the mandibular
condyle is slightly curved and tilted forward
at c.25° to the occlusal plane.
Like the articular eminence, its slope is
variable. In the coronal plane its shape
varies (Osborn & Baranger 1992) from that
of a gable (particularly marked in those
whose diet is hard), to roughly horizontal in
the edentulous.
The advantages and disadvantages of
covering articular surfaces with
 (A) and fibrous tissue
 (B). The addition of a fibrous disc
 (C) decreases the intra-articular
pressure while simultaneously
facilitating loaded sliding movements,
unique requirements of the
temporomandibular .. the precise
. Symptoms arising from the
temporomandibular joints and their
associated masticatory muscles are very
common (temporomandibular joint
syndrome/internal derangement).
Diffuse facial pain due to masseteric
muscle spasm, headache due to temporalis
muscle spasm and jaw ache due to lateral
pterygoid spasm are typical presenting
.These may be associated with clicking,
which is often audible whilst the patient is
chewing, and sometimes locking, when the
patient is unable to open fully.
Changes in the normal structure of the
articular disc occur and the disc does not
smoothly follow the movements of the
There is, however, irrefutable theoretical
evidence based on Newtonian mechanics
that the jaw joint is a weight-bearing joint
The non-working condyle is more loaded
than the condyle on the working side, which
may help explain why patients with a
fractured condyle choose to bite on the side
of the fracture abstract:
These symptoms affect predominantly
adolescents and young adults and affect
females more frequently than males. The
symptoms occur particularly when the
subject is under stress.
Although predisposing factors have been
implicated, such as the nature of the dental
occlusion, the morphology of the head of
the condyle, and variations in the
attachments of lateral pterygoid,
The articular tissues and the dense part of the
articular disc have no nerve supply. Branches of the
auriculotemporal and masseteric nerves and
postganglionic sympathetic nerves supply the
tissues associated with the capsular ligament and
the looser posterior bilaminar extension of the
The temporomandibular joint capsule, lateral
ligament and retroarticular tissue contain
mechanoreceptors and nociceptors. The input from
mechanoreceptors provides a source of
proprioceptive sensation that helps control
mandibular posture and movement.
The joint derives its arterial supply from the
superficial temporal artery laterally and the
maxillary artery medially.
Penetrating vessels that supply lateral
pterygoid may also supply the condyle of
the mandible.
Veins drain the anterior aspect of the joint
and associated tissues into the plexus
surrounding lateral pterygoid, and
Без категории
File Size
3 642 Кб
Пожаловаться на содержимое документа