3. CONTENTS
• Introduction
• Anatomical landmarks-definition
• Osteology
• Anatomy of maxilla and mandible
• Histology of oral mucous membrane
• Anatomical landmarks of maxilla and mandible
o Limiting structures
o Supporting structures
o Relief areas
• Correlation of anatomical landmark of maxilla and mandible
• Conclusion
• References
4. Introduction
• M.M Devan Dictum “Aim of a prosthodontist is not only
the meticulous replacement of what is missing, but also
perpetual preservation of what is present.”
• A prosthesis must function in harmony with the tissues
that support them and those that surround them.
• Hence the dentist must understand the macroscopic as
well as microscopic anatomy of the supporting and
limiting structures of the denture.
5. • This knowledge aids in determining –
i. The selective placement of forces by the denture bases
upon the supporting tissues.
ii. The form of the denture borders that will be harmonious
with the normal function of the limiting structures that
surround them.
6. Anatomical landmarks
It is defined as a recognizable anatomic structure used
as a point of reference
GPT -9
It includes
• Anatomical landmarks of maxilla
• Anatomical landmarks of mandible
7. Osteology
• The osseous structures not only support the dentures
but have a direct bearing on the impression making
procedures, the positioning of teeth & the contour of
finished denture bases.
• The maxillary denture is supported by 2 pairs of
bones, the maxilla & the palatine bones.
• The mandibular denture supported by one bone, the
mandible.
8. Maxilla
• There are two maxilla, each consisting of a central
body & four processes
• The four processes of maxilla are:
o Frontal
o Zygomatic
o Alveolar
o palatine
10. Alveolar & Palatine process of maxilla
• Involved in providing support for maxillary
denture.
11. Edentulous maxilla
• When natural teeth are present, the occlusal forces
are absorbed by the hydrodynamic effect of the PDL.
• This complete mechanism is related to the
maintenance of integrity of the alveolar process.
• But the loss of teeth deprives these processes of the
stimulus.
• Under dentures all forces are transmitted to surface
of the alveolar process as pressure.
• The total surface area of support from the maxilla is
22.96cm2.
12. Mucous membrane
• Serves as a cushion between the
denture base and the supporting
bone.
• Mucous membrane is composed of
mucosa and submucosa.
13. Histology of oral mucous membrane
Mucosa sub-mucosa
Formed by stratified squamous
epithelium and a subjacent narrow
layer of connective tissue is present
called as lamina propria.
Composed of connective tissue that
varies from dense to loose areolar
tissue.
In edentulous people – mucosa
covering hard palate + crest of residual
ridge + residual attached gingiva =
Masticatory Mucosa
Thickness varies and may contain
glandular, fat or muscle cells and
transmits the blood and nerve supply
to the mucosa
Characterized by well defined
keratinized layer on the outermost
surface
Attachment occurs between
submucosa and periosteal covering
of
the bone and it makes the bulk of the
mucous membrane
15. Masticatory mucosa
• Free, attached gingiva, hard palate
& crest of residual ridge.
• Comes in primary contact with food
during mastication.
• The epithelium is stratified
squamous orthokeratinized or
parakeratinized with a lamina
propria that is thick & dense.
16. Lining mucosa
• The mucous membrane that comes in contact
with the denture borders is usually lining mucosa.
• The lips, cheeks, vestibule, floor of the mouth,
ventral surface of the tongue and soft palate.
• Made up of stratified squamous non-keratinized
epithelium supported by thick lamina propria.
• The submucosal structure is either loosely or
tightly attached to underlying structures.
17. Specialized mucosa
• Seen on the dorsal surface (dorsum) of the tongue.
• It is covered with cornified epithelial papillae.
18. Anatomical landmarks of maxilla
Peripheral or limiting area
• Labial frenum
• Labial vestibule
• Buccal frenum
• Buccal vestibule
• Hamular notch
• Posterior palatal seal
22. Labial frenum
• Single narrow band of fibrous connective
tissue .
• May Consist of two or more fibrous bands
and can also be broad.
• Appears as a fold of mucous membrane
extending from the mucous lining of
mucous membrane of the lips to or
towards the crest of residual ridge on
labial surface.
23. Classification
According to Placek et al based on the extent of
attachment of fibers
• Mucosal
• Gingival
• Papillary
• Papilla penetrating
24. Significance
• On activation creates the labial notch
in the denture base.
• The activity of this area tends to be
vertical, so labial notch in denture
should be narrow i.e; just wide enough
and just deep enough to allow the
frenum to pass through it without
manipulation of lip.
• Since it contains no muscle fibers of
significance, it can be surgically
excised if it attaches too near crest of
alveolar ridge.
25. Clinical implication
• Recorded during border molding procedure which is
achieved by moving the lip outward, downward and
inward.
• Overzealous lateral movements may create a labial
notch that is too wide & loss of peripheral seal.
26. Labial vestibule
• Extends on both sides from the labial
frenum to the buccal frenum or between
the area of right & left first premolars if
the frenums are absent or in an unusual
location.
• The lining mucosa is devoid of
keratinized layer & is freely movable with
the tissues to which it is attached
because of the elastic nature of lamina
propria.
27. Significance
• Fibers of orbicularis oris runs in horizontal
direction so easy to overextend the
impression ,therefore careful border molding
necessary.
28. Clinical implication
• If the anterior alveolar ridge is fair to good, the labial border should be
quite thin about 2mm or less.
• A thicker border would eliminate the philtrum & would create an
undesirable “fat lip.”
• When the ridge is prominent an open or short flange may be used.
• If the ridge is poor or flat , thicker border needed for peripheral seal & as
an aid for lip support.
• Border molding is achieved by moving the lip outward, downward and
inward.
29. Buccal frenum
• Composed of one or more bands of fibrous
connective tissue
Muscles associated
• Buccinator: pulls frenum backward.
• Levator anguli oris: attaches beneath the
frenum & affects the position of the frenum.
• orbicularis oris: pulls frenum forward.
(Boucher;12th edition)
30. • The buccal frenum along with its associated muscles of
expression creates the buccal notch which is wider than
the labial notch because more clearance is needed for
the muscle activity in this area.
31. Modiolus
• Most of the muscles of expression
converge at the corner of the mouth
to form a nodule called modiolus.
32. Significance
• The oral activities in this area are horizontal as well as
vertical.
• Due to frequent activity of the buccal frenum and the
modiolus the border thickness of the buccal notch should
be fairly thin about 2mm.
33. Clinical implication
• If the ridge is flat or poor a wider border is necessary
for better peripheral seal as well as lip and cheek
support to improve esthetics.
• The movement of frenum is simulated by moving the
cheek outward, downward, inward, and then
backward and forward during border molding.
34. Buccal vestibule
• Extends from buccal frenum to hamular
notch
• It is bound externally by cheek & internally by
the residual alveolar ridge.
• Structures influencing buccal vestibule
o Buccinator
o massetor
o Coronoid process
35. Significance
Size of buccal vestibule varies with
o Contraction of buccinators muscle
o Position of mandible
o Amount of bone lost from maxilla
36. Clinical implication
• With increasing resorption of ridge, the zygomatic
process becomes more noticeable & care must be
taken not to use it as a stress bearing area.
• Buccal flange is border molded by extending the
cheek outward, downward & inward. The patient is
asked to open the mouth wide & move the mandible
from side to side.
37. Coronomaxillary space:Literature review
& anatomic description.
(Arbree et al ,JPD 1987:57;186-190)
• The coronomaxillary space is that anatomic region that
lies medial to the coronoid process and lateral to the
maxillary tuberosity.
Boundaries:
o anteriorly -by the base of the zygomatic process.
o posteriorly-pterygomaxillary or hamular notch
o inferioriorly - crest of the residual ridge.
38. • The coronomaxillary flange of the maxillary denture is
that portion of the buccal flange that extends from the
zygomatic eminence to the hamular notch.
39. • The coronoid process may be relatively
straight or vertical in some individuals .
For these patients opening of the
mandible can result in narrowing of the
space.
• If the individual with a lateral flare of
the coronoid process is observed
during opening, the space often
remains the same or becomes wider.
40. • If the space narrows during opening, any horizontal
overextension into the space would result in denture
base contact and loss of retention.
• Border molding procedures in this region should
include opening and closing, together with protrusion,
and lateral movements of the jaw.
41. • If the coronomaxillary space broadens or remains the
same size on opening , the functional filling of this
space with the denture flange becomes important.
• If the space is not completely filled or even slightly
overfilled, maximum retention may be lost.
• In this instance it is advisable not to have the patient
open wide, protrude, or move laterally during border
molding or impression procedures.
42. Hamular notch
• Hamular notch or pterygomaxillary notch
is a displaceable area about 2mm wide
• Situated between tuberosity of maxilla and
hamulus of the medial pterygoid plate
Instrument used:
• Identified by using mouth mirror so that edge
drops in definite depression.
43. • Determines the distal end of denture.
• The pterygomandibular raphe attaches to
Hamulus.
Significance
44. Clinical implication
• Ending the impression on the tuberosity will result in a non
retentive denture due to lack of peripheral seal.
• Overextending the impression distal to notch will usually
cause:
Extreme discomfort due to interference with ascending
ramus of mandible.
Restricted pterygomandibular raphe movement.
When mouth is wide open the denture dislodges.
45. • It is defined as the soft tissue area at or beyond the
junction of the hard and soft palate on which pressure
within the physiological limit can be applied by a
complete denture to aid in its retention.
(GPT – 9)
Posterior palatal seal
46. • Hardy and Kapur stated that retention and stability
that is achieved from adhesion ,cohesion and
interfacial surface tension are able to resist those
dislodging forces that are perpendicular to the
denture base.
• Horizontal & lateral torquing of the maxillary denture
can be resisted only by adequate border seal.
47. • Components of posterior palatal
seal:
o Pterygomaxillary seal area: extends
through pterygomaxillary notch
continuing 3-4mm anterolaterally
approximating mucogingival
junction.
o Postpalatal seal area: between the
anterior and posterior vibrating line
found medially from one tuberosity
to other.
48. • Boundaries :
o Anteriorly – Anterior vibrating line
o Posteriorly - Posterior vibrating line
o Laterally – Pterygomaxillary notch
49. M.M.House classification
Describes the amount of posterior tissue that will
accept the posterior palatal seal
• Class I – more than 5mm of movable tissue
available for post-damming; retention is usually
good.
• Class II – 1-5mm of movable tissue available for
post-damming good retention is usually
possible.
• Class III – less than 1mm movable tissue
available for post-damming; retention is usually
poor.
50. Significance
According to Ettinger and Scandrett :
• Aids in retention by maintaining constant contact with soft
palate.
• Prevents ingress of fluid, air, and food between denture
and tissue.
• Diminishes gagging reflux.
51. • Provides embedded sunken distal border
which is less conspicuous to tongue.
• Supplies a thick border to counteract denture
warpage due to dimensional changes during
polymerisation shrinkage of methy
methacrylate resin.
52. Methods to record posterior palatal seal
• Conventional approach using’T’burnisher
• Fluid wax technique
• Arbitrary scrapping of the master cast
53. Vibrating line
• It is defined as an imaginary line across the posterior
part of the palate marking the division between the
movable and immovable tissues of the soft palate.
This can be identified when the movable tissues are
functioning – (GPT-9).
54. Anterior vibrating line
• An imaginary line located at the junction of the attached
tissues overlying the hard palate and the movable tissues
of the immediately adjacent hard palate.
• Extends from one hamular notch to other.
• Passes 2mm in front of fovea palatine.
• Shape – bow shaped anteriorly, sometimes referred to as
“Cupid’s Bow.”
55. Significance
• Distal end of the denture should terminate 1 to 2 mm
posterior to the vibrating line.
Located by –
• Valsalva Maneuver -the nostrils are closed &patient is
asked to exhale through the nose. The soft palate will
flex at the junction .
• The line is drawn across the palate when it marks the
beginning of motion in the palate when an individual
says “ah” in short vigorous bursts.
56. Posterior vibrating line
• An imaginary line at the junction of the
aponeurosis of the tensor veli palatini and the
muscular portion of the soft palate.
• Located by - it can be visualised when the patient
says “ah” in a normal un exagg.erated fashion.
57.
58. Supporting structures
• It is defined as the surfaces of oral structures that
resists force, strains or pressures brought on them
during function (GPT-9).
It can be:
• Primary stress bearing area.
• Secondary stress bearing area.
59. According to 9th edition of Boucher & 12th edition
of Zarb & Bolender
• Primary sress bearing area
Residual ridge
• Secondary stress bearing area
Palatal rugae
60. According to Boucher’s 13 edition
• Primary stress bearing area
Firm tuberosity & hard palate on either side of palatal
raphae
• Secondary stress bearing area
Rugae & residual ridge
61. Hard palate
• The hard palate is made up of palatine
processes of the maxillae and the horizontal
plates of the palatine bones.
• The palatine process are joined together at
the medial suture.
62. o Trabecular pattern of bone is perpendicular to direction of
force.
o Lined by keratinized epithelium.
o The hard palate can be divided into areas
✔ Gingival
✔ Raphae
✔ Antereo-lateral
✔ Posterio-lateral
63. • The gingival & palatine raphae areas do not have a
distinct submucosa.
• Antereo-lateral area ,the submucosa consists of
adipose tissue & the postereo-lateral area consists
of palatal salivary gland tissue.
• Presence of fatty/ glandular tissue provides a more
resilient tissue for the support of a denture.
64. • Classification –according to Levin the shape of the hard palate
is
o Flat
o Rounded
o U – shaped
o V – shaped
65. Flat palate
• Resists vertical displacement but it is easily displaced by
lateral or torquing forces.
Rounded palate
• Has the best resistance to vertical and lateral forces.
66. U-shaped palate
• Good resistance to vertical and lateral forces.
V shaped palate
• Has got the least prognosis since any vertical or
torquing movements tends to break the seal
easily.
67. Crest of residual alveolar ridge
• The residual ridge is the remnant of
the alveolar process which originally
contained sockets for natural teeth.
68. Significance
• The submucosal layer is sufficiently thick to
provide resiliency for support of complete
denture
• The bone covering the crest of the upper ridge
is often compact.
• But the bone is subjected to resorption so it is
considered as secondary stress bearing area.
69. Factors influencing architecture of residual alveolar ridge
• Persons general health.
• Forces developed by the surrounding musculature.
• Severity of periodontal disease.
• Forces acquiring from wearing of dental prosthesis.
• Time length of edentulous span.
70. Maxillary rugae
• Raised areas of dense connective
tissue radiating from the midline in the
anterior one-third of the palate.
72. Significance
• Acts as secondary stress bearing area.
• Said to be concerned with phonetics.
• Increase the surface area of the foundation and thus
supplement the values of retention.
• It is the denture stabilizing area in the maxillary
foundation.
• Often compressed or distorted from an ill fitting
denture & should be allowed to return to their normal
form prior to impression making.
73. Maxillary tuberosity
• Most distal portion of the alveolar ridge.
• It is the posterior convexity of the maxillary
body.
74. Significance
• Important area of support as they are least likely to
resorb.
• Lateral reduction often required because the
coronoid process of the mandible is in close contact
during opening and lateral jaw movements which
may lead to an inadequate space for a correctly
extended buccal flange.
• Requires vertical reduction when it contacts the pear
shaped pad.
75. Relief areas
• These areas resorb under constant load or contain
fragile structures.
• Denture should be designed such that the
masticatory load is not concentrated in these areas.
76. Incisive papilla
• A pad of fibrous connective tissue
overlying the bony exit of the
nasopalatine blood vessels and
nerves.
77. Significance :
• Stable landmark and gives its relation to
incisive foramen through which the
neurovascular bundle emerge and lie on
the surface of bone.
• It is a biometric guide giving information on
positional relation to central incisors which
are about 8-10 mm anterior to incisive
papilla.
78. • Biometric guide which gives us
information about location of maxillary
canines (A perpendicular drawn posterior
to the centre of incisive papilla to sagittal
plane passes through canines).
79. Clinical Consideration :
• During final impression procedure, care should be taken
not to compress the papilla. Hence the incisive papilla
should be relieved with a spacer.
Reason :
a. Compression of blood vessels Obliteration of lumen
deprive nutrition to tissues breakdown of tissues.
b. Pressure on nerve causes paresthesia in the region of
upper lip.
80. Mid-palatine suture
• It is the area extending from the
incisive papilla to the distal end of
the hard palate.
81. Significance:
• Area of sutural joint and covered with firmly
adherent mucous membrane to the underlying
bone with thin layer of submucosal tissue.
• This sutural joint is formed by the median
fusion of two maxillary processes and two
horizontal plates of palatine bone.
82. Clinical implication
• As the bone of alveolar ridge resorbs, the pressure of
vertical forces is increased over the bone of palate.
• When this bone become prominent in mid-palatal
suture area, it becomes fulcrum point around which
the maxillary denture will rotate.
• This in turn results in discomfort to patient ,damage
of soft tissues and mid-line denture fracture.
83. Torus palatinus
• Hard bony enlargement that occurs in
the midline of the roof of the mouth.
• It’s size and shape varies greatly.
• Found in 20% of the population
(Zarb-Bolender,12th edition).
84. Significance
• It is covered by thin layer of mucous membrane
therefore relief to be given to avoid trauma.
• Relief should conform accurately to the shape of the
torus.
85. Clinical implication
• If the size is small ,can be relieved with pressure
indicating paste.
• Large tori has to be removed surgically.
• Sometimes the area of the torus can be cut out of the
denture & the use of a 1.5mm wide & 1mm deep
bead on the inside of the denture around torus may
suffice for adequate retention.
86. Fovea palatinae
• They are formed by coalesence of several
mucous ducts.
• Usually two in number on either side of the
midline.
• They indicate the vicinity of posterior
palatine seal area.
87. Significance
• Acts as a landmark for determining the posterior border
of denture.
• Denture can extend 1-2mm beyond fovea.
• A study of 72 subjects by Chen reported that only 25%
of the fovea were located on the vibrating line, none
were anterior, & the rest were posterior.
88. Clinical implication
• In patients with thick saliva, the fovea palatine should
be left uncovered or else thick saliva flows between
the tissue and increase the hydrostatic pressure and
hence lead to denture displacement.
92. Edentulous mandible
• The basal seat of the mandible is different in size from
basal seat of the maxilla.
• The submucosa in some parts of mandibular basal seat
contains anatomic structures that are different from those
found in the upper jaw.
• In addition, the nature of the supporting bone on the crest
of residual ridge usually differs between two jaws.
93. • The total area of support from the mandible is significantly less
than from maxilla.
Maxilla-22.96cm2 Mandible-12.25cm2
• This means that mandible is less capable of resisting occlusal
forces than the maxilla and extra care must be taken if available
support is to be used to advantage.
97. Labial frenum
• Usually a single narrow band but may consist two or
more bands.
• Shorter and wider than maxillary labial frenum.
• Contains a band of fibrous connective tissue that
helps attach the orbicularis muscle.
98. Significance
• The activity of this area tends to be
vertical , so the labial notch in the
denture should be narrow
• Because of attachment of orbicularis
muscle ,the frenum is sensitive and
active & denture must be fitted carefully
around it to maintain a seal without
causing soreness.
99. Labial vestibule
• Sulcus between the buccal frenum or between the
first premolars if the frenums are absent or in
unusual location.
• The major muscle in this area:
o Orbicularis oris
o Mentalis
100. Significance
• The fibers of orbicularis oris are horizontal, careful border
molding done to avoid over extension of denture
• Mentalis muscle originates from mental tubercles and
inserts into lower lip. It is a vertical muscle & excessive
activity in this area results in short flange.
101. Clinical implication
• Border molding is done by lifting the lower lip outward, upward &
inward.
• For effective border contact between denture and tissue, vestibule
should be completely filled with impression material during
impression procedure.
• The labial & buccal borders are not as critical for border seal
because of drape of the lips and cheeks create a facial seal. e.g;
denture with open or short flange-immediate dentures
102. • Ridge is fair to good then labial
border should be thin i.e; 1-
2mm
• Ridge is flat- thicker border
needed for lip & cheek support
& to provide better seal.
103. Buccal frenum
• Usually in the area of 1st premolar.
It may be a single band but often
two or more bands.
104. Significance
• Oral activities in this area are horizontal as
well as vertical(i.e. movements such as
puckering, grinning etc) so wider
clearance is usually needed.
• The contour of denture little narrower in
this area due to the activity of depressor
anguli oris muscle.
105. Clinical implication
• Border molding is done by lifting the
cheek outward, upward, inward,
backward & forward to simulate the
movement of frenum.
• The denture should extend less in
this region, and impression must be
functionally trimmed to have the
maximum seal and yet not displace
the denture when lip is moved.
106. Buccal vestibule
• Extends posteriorly from buccal
frenum to the outside back corner of
the retromolar pad.
• The impression is always widest in
this region since the buccal flange
swings wide into the cheeks
• The width & length mainly dependent
on the buccal shelf & buccinators
muscle.
107. Extent
• Influenced by buccinator muscle, which extends
from the modiolus anteriorly to the
pterygomandibular raphe posteriorly.
• Adequate support requires that the buccal flange
extend to outer edge of the buccal shelf or external
oblique line.
• The length of buccal flange is not critical because the
drape of the cheek provides a facial seal.
108. Clinical implication
• It is necessary to limit the lateral content of buccal flange in
the region where the masseter muscle is in function which
may push against the distal part of buccinator muscle, failure
of which may cause soreness of tissue when heavy pressure
is applied.
109. MASSETRIC NOTCH
► Seen buccal to crest of mandibular ridge in distobuccal corner
of the arch.
110. A) straight line- moderate activity
B) concavity- active muscle
C) convexity- inactive muscle
• It is recorded by asking the patient to exert a closing
force while dentist exerts a downward pressure on the
tray.
111. Retromolar pad
• Sicher has described retromolar pad as a soft elevation of
mucosa that lies distal to third molar .
112. Contents:
• Thin, non-keratinized epithelium
• Loose alveolar tissue
• Sub-mucosa: glandular tissue
• Muscle fibers:
o Laterally- buccinator
o Medially-Superior constrictor & Pterygomandibular raphe
o Distally-Terminal part of tendon of temporalis muscle
113. Pear shaped pad
• Term coined by Craddock & refers to the area
formed by residual scar of the third molar & the
retromolar papilla.
• The mucosa of pear shaped is usually attached
gingiva.
• The retromolar pad is posterior to pear shaped pad.
114. Significance
• The mandibular denture should terminate over distal edge
of pear shaped pad.
• Overextension at this border causes soreness & also limits
buccinator muscle.
115. LEVIN:
Considers the pear shaped pad as an area of support as it is an
area that rarely resorbs.
REASON:
Large and active temporalis muscle inserts on coronoid process
and anterior border of ramus with tendons ending on bone distal
to the pad.
Bone responds to tensile stimulation by growth and apposition
which causes areas of muscle attachments not to resorb
Thus, the pad is on a relatively stable bone.
116. • Important area of support because it is resistant to
resorption – active temporalis muscle insertion on
coronoid process & anterior border of ramus with
tendons ending on alveolar bone distal to pad.
• Landmark for the placement of the occlusal plane.
• Helps in arranging mandibular posterior teeth
117. Recording retromolar pad:
● Ask patient to open wide.
● If tray is too long: a notch is formed at the posteromedial border of
the retromolar pad, indicating encroachment of the tray on the
pterygomandibular raphe, thus tray must be adjusted accordingly.
118. Pterygo-mandibular raphae
• The pterygo-mandibular raphe or ligament originates
from the pterygoid hamulus of medial pterygoid plate and
attaches to distal end of mylohyoid ridge.
• Raphe is a tendinous insertion of two muscles.
o The superior constrictor is inserted posteromedially.
o Buccinator is inserted anterolaterally.
119. Clinical implication
• It is quite prominent in some patients and may even require
a notch like clearance in maxilla denture.
120. Lingual frenum
• Fibrous band of tissue that overlies the centre of
genioglossus muscle.
• It is usually a narrow single band of tissue but may be broad
and exist as two or more frenum.
121. • It originates at midline from ventral
surface of tongue and often
terminates at the sublingual (salivary)
caruncles.
• Often it fans out to find a broad
insertion in alveolar mucosa.
122. • They may be attached on or near the crest of ridge.
• The lingual frenum may be very short or tongue-tie,
the patient can hardly protrude the tongue.
• It is influenced by genioglossus muscle.
• The action of these muscles may raise and protrude
the tongue
123. Clinical implication
• During impression procedure the patient is asked to
touch tip of the tongue on incisive papilla region to
record the frenum.
• Careful clearance is needed in the denture because
the lingual frenum is attached to tongue and
inadequate clearance may result in pain or
displacement of denture.
124. Alveololingual sulcus
• Space between the residual alveolar
ridge and the tongue.
• Extends from the lingual frenum to the
retromylohyoid curtain.
126. Anterior lingual vestibule
• Extends from lingual frenum to
premylohyoid fossa.
• Premylohyoid fossa is palpable– seen as
premylohyoid eminence in impression.
• Mainly influenced by genioglossus and
lingual frenum.
127. • Lingual border of the impression should
contact the mucous membrane of the
floor of the mouth when the tip of the
tongue touches the upper incissors.
• Lingual flange should be shorter
anteriorly than posteriorly.
128. Mylohyoid area/middle vestibule
• Extends from pre-myohyoid fossa to the
distal end of the mylohyoid ridge
• Mainly influenced by mylohyoid muscle
• Lingual flange should slope toward
tongue.
• Aids in stabilizing the denture as the
tongue rests over it
129. • Provides space for raising the floor of the mouth without
displacing the denture & peripheral seal is maintained
during function.
• The length and width of mylohyoid flange is determined
by membrane attachment of tongue to mylohyoid ridge
and width of hyoglossus muscle and can only be
determined by skillful border molding and impression.
130. Retromylohyoid fossa
• The flange passes into the retromylohyoid
fossa.
• Since it is not acted upon by the
mylohyoid in the retromylohyoid fossa it
turns laterally toward the ramus to fill the
fossa & complete the typical ‘S’ form of
lingual flange.
132. Retromylohyoid curtain
• It is a curtain formed by mucous membrane
in the oral cavity.
• Bounded by
o Posteriolaterally- superior constrictor
muscle
o Posteriomedially- palatoglossus & lateral
surface of tongue
o Inferiorly- submandibular salivary gland &
mylohyoid muscle
133. NEIL’S LATERAL THROAT FORM
Described that the lingual flange
could have three possible lengths
depending on the tonicity, activity &
anatomic attachments of the adjacent
structures
134. Class I
• long and wide flange.
• Thickness varies
• The retromylohyoid curtain area
(most distal border )should be
thinner.
Class II
• It is half as long and narrow as class
I and twice as long as class III.
135. Class III
• Minimum length and thickness.
• Border 2-3 mm below mylohyoid
ridge or sometimes at the ridge.
• Thickness not more than 2mm
• Knife-edge border if border
terminates at mylohyoid ridge.
136. Significance
• It forms the distal end of alveolingual sulcus.
• The denture border should extend posteriorly to
contact the retromylohyoid curtain when the tip of
tongue is placed against the front part of upper residual
ridge.
• Protrusion of the tongue causes the retromylohyoid
curtain to move forward.
138. Buccal shelf area
• Primary area of support of
mandibular denture.
• It is between the mandibular
buccal frenum & anterior edge of
masseter muscle.
• Boundaries
o Medially – crest of alveolar ridge
o Laterally – external oblique ridge
o posteriorly– retromolar pad
o Anteriorly –buccal frenum
139. Significance
• The mucous membrane covering the buccal shelf area is
loosely attached, less keratinized & contains thick
submucosal layer.
• Bone of the buccal shelf is covered by a layer of cortical
bone & also it lies at right angles to the vertical occlusal
forces , makes it most suitable primary stress bearing
area
• The buccal shelf area tends not to resorb due to the
stimulation of the attachment of buccinators.
140. Clinical implication
• When the ridge is flat, the buccinators is often
attached almost the center of ridge.
• The buccinators can be covered in this area because
it is relatively flaccid, inactive & fibers function in a
horizontal direction.
141. Residual alveolar ridge
• It is covered by fibrous connective
tissue and underlying bone is
cancellous.
• The mucous membrane covering
the crest of the residual ridge is
covered by keratinized layer and is
attached by its submucosa to the
periosteum of the mandible.
142. • The mucous membrane of crest of ridge when securely
attached to underlying bone provides good soft tissue
support for denture.
• Underlying bone is cancellous, the crest of the residual
ridge may not be favorable as the primary stress-
bearing area for a lower denture.
• The slopes of residual ridge have thin plate of cortical
bone & at an acute angle to occlusal forces- secondary
stress bearing area.
144. Mylohyoid ridge
• The mylohyoid ridge is a bony
prominence along the lingual aspect
of the mandible.
• Soft tissue usually hides the
sharpness of mylohyoid ridge.
• Anteriorly, mylohyoid ridge is close
to inferior surface of mandible &
posteriorly to crest of residual ridge.
145. • Posteriorly, after resorption, it often flushes with the
residual ridge.
The position of the mylohyoid ridge as it varies relative to
the degree of alveolar ridge resorption
146. Significance:
• A prominent sharp ridge interfere with the
development of correct lingual flange & cause pain
especially during mastication.
• The mucous membrane overlying the sharp or
irregular mylohyoid ridge needs to be relieved.
147. Mental foramen
• It is located on the lateral surface of body
of mandible between the 1st & 2nd
bicuspids about halfway between the
lower border of mandible & the alveolar
crest.
148. Significance
• As resorption occurs mental foramen will come to lie
closer to the crest of residual ridge.
• Unless relief is provided the nerves and blood
vessels will get compressed by the denture.
• Pressure on the mental nerve can cause numbness
of lower lip.
149. Genial tubercle
• The genial tubercle are a pair of dense
bony prominences at the inferior
border of the mandible at the lingual
midline.
• It lies away from the crest of the ridge.
• They become relevant in the denture
when there is excessive resorption of
the residual ridge.
150. Significance
• Due to resorption they become
increasingly prominent & hence
relief is essential to avoid
complications.
151. Torus mandibularis
• It is a bony prominence usually found
bilaterally and lingually near the first
and second premolars midway
between the soft tissues of the floor of
the mouth and crest of alveolar ridge.
• In edentulous mouth, the superior
border of torus may be flush with the
crest of ridge.
• It is covered by thin layer of mucous
membrane.
152. Significance
• Small tori may only require relief in the denture.
• Large tori needs to be removed surgically- difficult to
provide relief within the denture without breaking
border seal.
153. The tongue
• It is composed mainly of muscle fibers and its
associated Muscles (genioglossus, hyoglossus,
styloglossus).
• The active tongue can easily displace even best
fitting denture.
154. • To evaluate the tongue position, instruct
patients to open just wide enough for a small
portion of food and observe the different
positions of tongue.
• In normal position, the tongue appears
relaxed and completely fills the lower arch
with its apex lightly contacting the lingual of
lower teeth. This position is important for
lingual border seal.
156. Conclusion
• The basic goal of a successful complete denture therapy is
reaching the patients expectations in fulfillment of better
masticatory ability, unaltered speech and a better esthetics.
• The clinician should have the anatomical knowledge to
fabricate prosthesis which inturn aids in proper maintenance
of stomatognathic system.
157. • The knowledge of oral anatomy, microscopic as well as
macroscopic features, better equips a prosthodontists to -
i. Decide how to make the impression?
ii. What material to use?
iii. How to plan the treatment?
• All this will result in a successful prosthetic treatment.
159. A variation in the anatomic position of the
pterygomandibular raphe: report of case
Journal of the American Dental Association. 1987 May 1;114(5):631-2.
► REPORT OF CASE
A 67 yr old male presented with lack of maxillary denture retention since 4 years.
ON EXAMINATION
• The ptergomandibular raphe inserted bilaterally into the maxillary tuberosity
than on the expected region of hamulus.
• On left side it was more prominent as the raphe was attached on the crest of
tuberosity.
• The position prevented posterior extension of maxillary denture to the level of
ptergomaxillary notch.
160. Treatment
► Under local infilteration, bilaterally tissues were removed from maxillary
tuberosity region.
► The last denture used was relined with tissue conditioner and attached to
maxilla with palatal screw which acted as a surgical stent.
► After healing, stent was relined with autopolymerised acrylic resin and
used as transitional maxillary denture.
► Patient worn this appliance for 3 months and had good retention.
► Later definite prosthesis was made.
161. CONCLUSION
► It is important to check for the position of ptergomandibular raphe before
fabrication of denture base.
162. Relationship of the maxillary central incisors and
canines to the incisive papilla.
Journal of oral rehabilitation. 1975 Jul 1;2(3):309-12.
► PURPOSE
The purpose of this study was to ascertain;
(a) whether there is a constant relationship between the central incisors,
canines and the incisive papilla.
(b) if this relationship varies for different arch shapes.
(c) the reliability of these findings as aids in the design of full dentures.
163. METHOD OF STUDY
► Four hundred and thirty dentulous maxillary casts were selected for the
study.
► Casts used were taken from an epidemioiogical survey.
► The participants represented both men and women with an age range of
17-35 years.
► Only casts in which no teeth were missing and the teeth were in normal
alignment with Angle's Class I relationship were considered.
164. The following measurements and observations were made;
► (a) the distance between the canine cusp tips.
► (b) the relationship between the line joining the canine cusps and
the papilla.
► (c) the distance from the posterior edge of the papilla to the labial
edge of the maxillary right central Incisor.
► (d) arch shape.
165. RESULT
Shape of Arch
277 of casts examined were of the oval type, 110 were square, 43 were
tapering.
The average distance between the canine cusp tips was 34-66 mm—with
a range from 33. 04 to 35.67 mm.
The line joining the tips of the upper canines varied in relation to the
incisive papilla.
In 248 casts the line crossed the center of the papilla.
In 72 casts it was anterior to the center of the papilla.
In 110 casts the line was posterior to the center of the papilla.
166. Three-dimensional analysis of the occlusal plane related
to the hamular–incisive–papilla occlusal plane in young
adults.
Journal of oral rehabilitation. 2007 Feb;34(2):136-40.
► AIM
The study was to estimate the relationship between the various occlusal
planes and the HIP plane in Taiwanese young adults with approximately
optimal occlusion.
► METHOD OF STUDY
► Taiwanese subjects (50 men and 50 women), with no history of
orthodontic treatment selected.
► The ages of the subjects ranged from 19 to 28 years.
167. ► Maxillary irreversible hydrocolloid impressions were
made in subjects. Stone casts† were then poured in them
immediately.
► All marked points on the maxillary casts were measured
by a three-dimensional precise measuring device.
► The angular relationship between the four various
occlusal planes and the HIP plane were investigated.
► The vertical distances between the cusp tips and incisal
edges of maxillary teeth to the HIP plane were measured.
168. ► Data were performed by the Statistic analysis software programme.
► The Student’s t-test and Pearson’s correlation test were used to test the
statistical significance.
RESULTS
The results showed that the occlusal plane defined as the incisal edge
of maxillary central incisor to mesiobuccal cusp tips of maxillary
second molars had the smallest included angle with the HIP plane.
The incisal edge of maxillary right central incisal to mesiopalatal cusp
tips of maxillary first molars had the largest included angle with the
HIP plane.
The curve drawn through the buccal cusp tips of maxillary teeth had
better parallelism with the HIP plane.
169. Effect of Relining Method on Dimensional Accuracy of
Posterior Palatal Seal. An In Vitro Study
Journal of Prosthodontics. 2008 Apr;17(3):211-8.
► Purpose:
The posterior palatal seal contributes to the retention of the complete
denture. Distortion of this area can occur during reline procedures. The
purpose of this study was to evaluate the dimensional accuracy of
various denture relining methods and materials on the maxillary
posterior palatal seal area.
170. MATERIALS AND METHODS
► Dentures were fabricated on 50 definitive casts made from the original
metal cast.
► Five relining methods and materials were evaluated during this study,
(I) laboratory conventional heat-polymerizing method (Lucitone),
(II) laboratory heat/pressurepolymerizing method (SR-Ivocap),
(III) laboratory autopolymerizing method (Perm),
(IV) chairside autopolymerizing method (Tokuso Rebase),
(V) chairside lightpolymerizing method (Astron).
► The dimensional changes of the posterior palatal seal areas were
determined by placing a low-viscosity silicone impression material
between the metal cast and the tissue surface of the relined dentures.
171. CONCLUSION
► The dimensional accuracy of relined dentures is influenced by relining
materials and methods.
► Statistically significant differences (p < 0.0001) were revealed among
the tested groups.
► According to this study, the autopolymerizing direct chairside relining
method is significantly more likely to produce smaller gaps in the
posterior palatal seal area than the rest of the examined methods.
172. Evaluation of the Reliability of Hamular Notch-Incisive
Papilla Plane (HIP) in Establishing Occlusal Plane.
Orthodontic Journal of Nepal. 2014 Oct 24;4(1):45-7.
Objective:
•To find the relationship between hamular notch-incisive papilla plane and
occlusal plane in dentulous subjects.
Materials & Method:
•48 dentate subjects with normal Class I occlusion participated in the study.
•Their maxillary impressions were made and casts were poured.
•Each cast was then mounted in the surveyor and HIP plane made parallel
to the floor by tripoding method.
•With the cast in this relation, the vertical distance between HIP and various
reference points of occlusal planes were measured using digital Vernier
Caliper.
•Wilcoxon test was used to find the statistical difference.
173. Conclusion:
HIP plane tends to be parallel to occlusal plane and can be used as a
clinical guideline in the determination of inclination of the occlusal
plane.
174. Quantifying the Selection of Maxillary Anterior Teeth
Using Intraoral and Extraoral Anatomical Landmarks
The aim
To determine if a relationship exists between intraoral and extraoral facial
measurements that could assist dental practitioners in selecting esthetically
appropriate maxillary anterior teeth in the absence of pre-extraction records.
Materials and methods:
• A cross-sectional study design was used with a sample size of one hundred and
twenty participants.
• A questionnaire was used to identify the selection criteria and a photograph was
taken for facial measurements using digitally calibrated software.
• Ninety-eight participants met the selection criteria and were included in the study.
Measurements of intraoral landmarks were taken from stone casts of maxillary
impressions using calibrated digital calipers.
175. ► Each measurement was completed by two assessors to obtain mean
values.
► Data were statistically analyzed using SPSS version 17 software.
► Data were assessed by one way analysis of variance (ANOVA) followed
by post hoc (p < 0.05) to find any difference between tested groups.
► Pearson coefficients were used to determine whether correlation exists
between measurements.
Conclusion:
The study showed that the average length and width of the maxillary
arch and interalar width were the anatomical landmarks that provided
the strongest predictive relationship with anterior maxillary teeth.
176. References:
1. Zarb,Bolender,Carlson – Boucher’s prosthodontic treatment for
edentulous patients,12th edition
2. Sharry J.J. – Complete denture prosthodontics;ed.3.New York,1974
3. Heartwell Charles – syllabus for complete dentures
Ed.4,Philadelphia
4. Sheldon Winkler – Essentials of complete denture
Prosthodontics,ed.2
5. O Boucher – Swenson’s complete denture Prosthodontics,ed.6
177. 6. Benard Lynn,Detriot,Mich – Significance of anatomic landmarks in
complete denture service,JPD,1964,14:456-459
7. H.R.Kolb-Variable denture limiting structures of the edentulous
mouth,Part 1 ,maxillary border areas,JPD 1966,16:194-204
8. Colie H Millsap-The posterior palatal seal area for complete
denture.DCNA,Nov.1964,663
9. Inderbir Singh-Textbook of human histology with colour atlas,ed.3
10. Orban-Oral histology & embryology,ed.10
11. Elinger-synopsis of complete denture prosthodontics,ed.1
12. N. S. Arbree, D.D.S.,* A. A. Yurkstas, D.M.D., M.S.,** and J. H.
Kronman, D.D.S.,Ph.D.***Tufts University, School of Dental Medicine,
Boston, Mass.
