Prosthodontic Importance of Intraoral Anatomical Landmarks

1. INTRAORAL ANATOMICAL
LANDMARKS OF
PROSTHODONTIC
IMPORTANCE
By
Dr. Mohammed M. Fouad
Prof. of Removable Prosthodontics
Faculty of Dentistry
Mansoura University

2. Prof Dr Mohammed M Fouad 2
Objectives:
• To give Knowledge's about the intraoral
anatomical landmarks (denture bearing
areas, and denture boundaries) of
prosthodontic importance to fabricate a
complete denture that has maximum
retention, stability and support with
preservation of these underlying and
surrounding structures.
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Intraoral Anatomical Landmarks of
prosthetic importance
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5. Intraoral Maxillary
Anatomical landmarks
1. LIMITING STRUCTURES.
2. SUPPORTING STRUCTURES.
3. RELIEF AREAS.
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Intraoral Maxillary Anatomical
landmarks
1. LIMITING STRUCTURES:
 The labial frenum.
 The labial vestibule.
 The buccal frenum.
 The buccal vestibule.
 The hamular notch
 Soft palate, Vibrating lines and
Posterior palatal seal area:
2. SUPPORTING STRUCTURES :
 The residual alveolar ridge.
 Maxillary tuberosity.
 Hard palate (Palatine vault).
 Rugae area.
3. RELIEF AREAS:
 The incisive papilla.
 Median palatine raphe (suture).
 Torus palatinus.
 The fovea palatina
3.
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Border structures that limits the
periphery of the maxillary denture
• The labial frenum
• Labial vestibule
• Buccal frenum
• Buccal vestibule
• Hamular notch
• Vibrating line of the soft palate
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8. THE LABIAL FRENUM AND LABIAL VESTIBULE
• The labial frenum:
• Fold of mucous membrane, no muscle and
no action of its own.
• A “V” shaped notch should be recorded
during impression making and a labial notch
in the labial flange of the denture must be
just wide and deep enough to accommodate
the labial frenum.
• The labial vestibule:
• It is divided left and right by the labial
frenum
• Orbicularis oris is the main muscle which
forms the outer surface of the labial
vestibule . It has only an indirect effect on
the labial vestibule because its fibers run
in horizontal direction.
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9. THE BUCCAL FRENUM AND BUCCAL VESTIBULE
• Buccal frenum:
• Dividing line between the labial and buccal
vestibule. May be single or double.
• Levetor anguli oris muscle attaches beneath
the frenum.
• Orbicularis muscle pulls the frenum forward,
and buccinator muscle pulls it backward.
• Require more clearence for its action
• Buccal vestibule:
• Extend from buccal frenum to hamular notch
• Bounded laterally by the cheeks and medially
by the ridge.
• Size of the vestibule varies with the
contraction of buccinator muscle, position of
the mandible, and amount of bone lost from
maxilla.
• Adequate depth/width should be recorded
•
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10. The hamular notch.
• Distal limit of the buccal
vestibule.
• Situated between the
tubrosity and hamulus of
the medial pterygoid
bone.
• Aids in achieving
posterior palatal seal.
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11. Soft palate, Vibrating lines and
Posterior palatal seal area:
• Imaginary line across the posterior
part of the palate making the division
between the movable and immovable
tissues of the soft palate which can be
identified when the movable tissues
are moving
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Residual alveolar ridge
Description Significance
- The portion of the alveolar
process and it's soft tissue
covering that remains after
extraction. (Arch/Ridge)
- Covered by a dense connective
tissue fibers so, it is considered
as a secondary stress bearing
area (resorbed with time).
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Maxillary tuberosity
Description Significance
-Bony prominence
located posterior to
the maxillary 3rd
molar.
- Aid in support, retention and stability maxillary
complete denture.
- When it is large:
1- Relieved.
2- Modify the path of insertion.
3- Surgical removal.
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Hard palate and Palatine vault
Description Significance
•Formed anteriorly by the hard
palate and posteriorly by the
soft palate.
•The palatal surface of the
alveolar arch forms the lateral
and anterior boundaries of the
vault.
-The palatal vault may be high and V
shaped, or shallow and flat.
-The U shaped hard palate is more
desirable for denture stability
-The horizontal portion of the hard
palate is considered the primary
stress-bearing area for the upper
denture.
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Incisive papilla
Description Significance
- Pear-shaped elevation present
in the midline behind the 2
centrals.
- After extraction of teeth it migrates to
the crest of the ridge.
- It should be relieved to avoid the
burning sensation of the palate.
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Palatine rugae
Description Significance
- It is irregular elevations
radiates from the
midline of the anterior
part of the palate.
- 2ry stress bearing area.
- Prevent forward movement of the denture.
- If it is sensitive or prominent it should be
relived.
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Median palatine raphe
Description Significance
-The
mucoperiostium
that covers the
median palatine
suture.
- When it is prominent it should be relieved.
- Lack of relief cause:
1- rocking of the denture due to bone
resorption.
2- Tissue ulceration.
3- Midline denture fracture.
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Torus palatinus
Description Significance
- Bony prominence
present at both sides
of the midline of the
palate.
- It should be:
1- Relieved.
2- Surgical removal.
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21. Fovea palatinae
Description Significance
- Two openings of minor
salivary glands present in both
sides of the midline posterior to
junction of hard and soft palate.
- It determines the posterior
extension of the upper
complete denture to be 2mm
posterior to it.
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22. Prof Dr Mohammed M Fouad 22
Interpreting anatomic maxillary
landmarks (Impression)
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23. Intraoral mandibular
anatomical landmarks
1. LIMITING STRUCTURES.
2. SUPPORTING STRUCTURES.
3. RELIEF AREAS.
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24. Prof Dr Mohammed M Fouad 24
Intraoral mandibular landmarks
1. LIMITING STRUCTURES:
 Labial frenum
 Labial vestibule
 Buccal frenum
 Buccal vestibule
 Retromolar bade
 Lingual frenum
 Lingual pouch (Retromylohyoid
Space)
 Sublingual fold (Crescent area )
2. SUPPORTING STRUCTURES :
 Residual alveolar ridge
 External oblique ridge
 Buccal shelf area
3. RELIEF AREAS:
 Mental foramen
 Torus mandibularis
 Internal oblique ridge (mylohyoid
ridge)
 Genial tubercles
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Border structures that limits the
periphery of the mandibular denture
• Labial frenum Labial vestibule
• Buccal frenum
• Buccal vestibule
• Masseter muscle influencing
area
• Retromolar pad
• Lingual border anatomy
 Palatoglossal arch
 LInguaI pouch
 Sublingual salivary gland area
 Lingual frenum
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 The labial frenum
 The buccal frenum
 The lingual frenum
 The labial vestibule
 The buccal vestibule
 The lingual pouch
 The sublingual fold (Crescent area )
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Retromolar pad:
• A pear-shaped bulge of mucous
membrane at the posterior end of
the mandibular residual alveolar
ridge. It is a pad of loose, areolar
tissue that contains retromolar
mucous glands.
• Because of its spongy nature it
acts as a cushion or shock
absorbent. It also provides a
posterior seal for the mandibular
denture.
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Residual Alveolar ridge
• The part of the alveolar
process and its soft tissue
covering that remains after
extraction of teeth.
• It is formed of cancellous
bone, thus it is unsuitable
as a primary stress bearing
area for mandibular
denture.
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External oblique ridge:
• A ridge of dense bone extending
from just above the mental
foramen superiorly and distally,
and then becomes continuous with
the anterior border of the ramus of
the mandible.
• The lower denture should cover
but not extend beyond this ridge to
avoid denture displacement by the
powerful musculature in this area.
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Buccal shelf area:
• It is bounded externally by the
external oblique ridge and
internally by the slope of the
residual ridge.
• Its bone is very dense and forces
of occlusion can be directed more
nearly at right angles to it, so, it is
considered as a primary stress
bearing area and should be
covered by the lower denture to
provide support.
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Mental foramen:
• On the buccal surface of the mandible
between the roots of the first and
second premolar.
• The mental nerves and vessels pass
through it.
• In cases of sever ridge resorption, it is
usually located near or on the crest of
the ridge. In such cases, relief of the
denture is necessary to avoid pain and
numbness of the lower lip.
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Internal oblique ridge (mylohyoid ridge)
• A ridge that extends near the inferior border
of the mandible in the incisal region, and
then it becomes progressively higher
posteriorly till terminates just distal to a
slight prominence (the lingual tuberosity). It
gives attachment to the mylohyoid muscle
that forms the floor of the mouth.
• It should be included in the denture bearing
area. In cases of excessive bone resorption,
the mylohyoid ridge comes to lie close to
the crest of the residual ridge. When it is
sharp and prominent, it should be reduced
surgically or otherwise relieved.
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Torus mandibularis :
• A unilateral or bilateral bony
projection sometimes found on
the inner surface of the
premolar region in the
mandible. Covered by a thin
mucous membrane.
• Relief of the lower denture in
this area is necessary. When it
is large, and interferes with the
seating of denture, it should be
surgically removed.
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Genial tubercles:
• Two small prominences on the inner
surface of the mandible, one on each
side of the symphesis. The genio-
glossi muscles are attached to their
upper surface and the geniohyoid to
their lower surfaces.
• In extreme alveolar bone resorption;
they may be located on the crest of
the ridge. In such cases relief of the
lower denture must be made
opposite to their position.
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35. Prof Dr Mohammed M Fouad 35
Interpreting anatomic mandibular
landmarks (Impression)
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36. Conclusion:
Thus, a sound knowledge of the anatomical
landmarks of the edentulous jaw is a prerequisite
if one has to achieve the objective of fabricating a
complete denture that has maximum retention,
stability and support with preservation of
underlying structures with minimum post
insertion problems.
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Questions:
• Discuss the Prosthodontic importance of:
1. Buccal shelf area
2. Fovea palatinae
3. Incisive papilla
4. Palatine vault
• Discuss border structures that limits the
periphery of the maxillary denture.
• Discuss border structures that limits the
periphery of the mandibular denture.
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38. References:
• Boucher's Prosthodontics
• Essential of complete denture prosthesis
by Sheldon Winkler
• Clinical dental prosthetics by h r b fenn
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39. Prof Dr Mohammed M Fouad 39
Thank you
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