WEL-COME
ORAL ANATOMY IN
RELATION TO COMPLETE
DENTURE CONSTRUCTION.
DR. TAJMULLA AHMED
a.tajammul@gmail.com
UNIVERSITY OF MAJMAAH,
COLLEGE OF DENTISTRY, AZ-ZULFI, KSA.
Intended learning outcome.
At the end of the class students should be able;
To enumerate, identify and mark all anotomical landmarks of
edentulous maxilla and mandible on study models.
To identify and apply the importance and clinical importance
of the landmarks necessary for future semesters during
fabrication of complete dentures for edentulous patients.
Why to study anatomical landmarks?
In today's Era life expectancy has markedly
increased,
So has number of elders in our society. Many of
these will need complete denture.
So in order to construct a prosthesis the dentist
not only, must understand both the, physiology
and psychology of the patients, but also
macroscopic and microscopic anatomy of the
supporting and limiting structures of the
denture.
supporting structures .
Maxillary and mandibular dentures transfer occlusal loads to these so
called supporting structures .
The ultimate support for a denture is by; the underlying bone, covered
by mucous membrane.
Support of maxillary denture is by; maxillae and palatine bone.
For mandibular denture, support is by; mandible.
2 types of bones are seen
The nature of bone and its site of location
place an important role in determining the
areas of stress distribution.
Compact or cortical bone
Cancellous or Trabecular bone
Oral mucous membrane
Denture bases rest on the mucous membrane, which serve as a cushion between
denture base and supporting bone.
The mucous membrane composed of :(i) Mucosa
(ii) Sub mucosa
Classification of oral mucosa depending on its location.
(i) Masticatory mucosa:
(ii) Lining mucosa:
(iii)Specialized mucosa:
In edentulous patients, it
covers the crest of alveolar
ridge and the hard palate.
It forms the covering of lips , cheeks,
vestibular spaces, alveolingual sulcus,
soft palate , ventral surface of the
tongue and an unattached gingival
fold on the slope of the residual ridge.
It covers the dorsal
surface of the tongue.
Anatomical landmarks in maxilla
Classification;
a} Limiting structures
- Labial frenum
b} Supporting structures
- Labial vestibule
-Hard palate
- Buccal frenum
-Residual ridge
-Palatal rugae
- Buccal vestibule
- Hamular notch
- Posterior palatal seal
area
c} Relief areas
- Incisive papilla
- Midpalatine raphe
- Fovea palatine
Labial frenum
Term Frenum / Frenulum refers to a connecting fold of mucous membrane.
Labial frenum, is fan shape, a fold of mucous
membrane extends from the labial mucous membrane
reflection area to the slope or crest of residual ridge at
the midline.
It contains no muscle and has no action on its own.
Action of the lip in this area is mainly vertical.
Labial vestibule
The labial vestibule is divided into a left and right
labial vestibule by the labial frenum and extends upto
the buccal frenum on either side.
The main muscle of the lip, which forms the outer
surface of the labial vestibule, is the orbicularis oris.
Buccal frenum
Buccal frenum is a fold of mucous membrane which extends from the
Buccal mucous membrane reflection area to or towards the slope or crest
of residual ridge.
It is sometimes a single fold of mucous membrane, sometimes double,
and in some mouth, broad and fan shaped.
It records in the impression as a buccal notch which is properly relieved
and molded.
It should be cresentic in form rather than ‘V’ shaped.
Buccal vestibule
It is defined as “The portion of oral cavity that is
bounded on one side by the teeth, gingiva and
alveolar ridge (residual alveolar ridge) and on the
lateral side by the cheek posterior to the buccal
frenum’.GPT-8.
It lies opposite the tuberosity and extends from
the buccal frenum to the hamular notch
Coronomaxillary space
Definition:The coronomaxillary space is that
anatomic region that lies medial
to the coronoid process and
lateral to the maxillary tuberosity.
Hamular notch
Hamular notch is a displaceable area,
about 2mm wide between the tuberosity of
the maxilla and the hamular process of the
medial pterygoid plate.
Also called as Pterygomaxillary notch.
This notch is used as a boundary of the
posterior border of the maxillary denture.
If the denture extends too far into the
hamular notch, the mucous membrane
covering the raphe will be traumatized.
Posterior Palatal seal area.
The soft tissue area at or beyond the junction of the hard
and soft palates on which pressure,within physiologic
limits, can be applied by a denture to aid in its retention”.
(GPT-8).
Posterior palatal seal has following advantages:
Provides firm contact of denture base with the tissue which eliminates
gagging.
Provides thick borders to counter act warpage.
Provides a good retention by forming a posterior seal
Provides close contact with mucous membrane which prevents food
getting under the denture.
It forms sunken distal borders which are less conspicous to tongue
Palatine fovea regionThe fovea palatinae are indentations near the
midline of the palate in posterior region
formed by coalescence of several mucous
membrane ducts.
They are very prominent in some individuals,
whereas in others they are barely visible or
may be absent.
Soft palate
The soft palate is a curtain of soft tissue
attached anteriorly to the lower surface
of the posterior border of the hard palate
and laterally to the walls of the pharynx.
Anterior vibrating line
Anterior vibrating line is an imaginary line located at
the junction of the attached tissues overlying the
hard palate and the movable tissues of the
immediately adjacent soft palate.
This can be located either by valsalva maneuver, by
instructing patient to say “ah” with short vigorous
bursts.
Posterior vibrating line
It represents the demarcation between that part of the soft palate that has
limited or shallow movement during function and the remainder of soft palate
that is markedly displaced during function.
Posterior vibrating line is visualized by instructing the patient to say “ah” in a
normal unexaggerated fashion.
The distal end of the upper denture must extend at least to vibrating lines. In
most instances the denture should end 1-2 mm posterior to vibrating lines.
Anatomical landmarks of supporting
structures in maxillary region
AREAS OF SUPPORT (LEVIN)
PRIMARY – areas perpendicular to the occlusal forces & usually do not resorb
easily
SECONDARY- areas more than 90 o to or perpendicular to occlusal forces but
resorb easily
SLIGHT – areas of very displacable tissues, vestibular tissues , peripheral seal
areas
Hard palate
The ultimate support for the maxillary denture is
the bone of two maxillae and palatine bone.
They provide primary support for the
denture.[has shown to resist the resorptive
changes.]
Palatine rugae
Rugae are the raised area of dense connective
tissue radiating from the median suture in the
anterior one third of the palate.
In the area of the rugae, the palate is set at an
angle to the residual ridge and is rather thinly
covered by soft tissue. This area contributes to the
stress-bearing role as well as to retention although
in a secondary capacity.
Torus palatinus
The torus palatinus is a hard bony enlargement
that occurs in the midline of the roof of the mouth.
It is covered by a thin layer of mucous membrane.
It is easily traumatized by the denture base
unless a relief is provided.
Residual alveolar ridge
“The portion of the alveolar ridge and its soft tissue covering, which
remains following the removal of teeth”.(GPT-8).
When the natural teeth are removed, the alveoli begin to fill up with the
new bone. At the same time bone around the margins of tooth sockets
begin to shrink awayresulting in formation of residual alveolar ridge.
Maxillary tuberosity.
Bulbous extension of residual
ridge in 2nd & 3rd molar region.
Important area of support
Gross enlargement (fibrous or
bony –surgical correction.
Anatomical landmarks of relief
structures in maxillary region
Incisive papilla
This covers the incisive foramen and is located in the midline
immediately behind and between central incisors.
Incisive papilla is used to locate the midline of the dental arch.
The nasopalatine nerves and blood vessels pass through the foramen
Care should be taken that the denture base does not impinge on them
and hence should be relieved.
Fovea palatini
These are clinically visible pits near the
midline of the palate. They are the
ductal openings and recipients of
distributaries of ducts of the
surrounding clusters of mucous glands.
Mid palatine raphe
This presents as slightly elevated bony ridge along
the midline of hard palate.
Adequate relief should be provided in this area as,
mucosa covering the raphe is extremely thin and
is traumatized easily.
Anatomical landmarks in mandibular region.
Supporting
structures
Limiting structures
- Labial frenum
-Labial vestibule
-Buccal frenum
-buccal shelf area.
Refief areas
-residual alveolar
ridge.
-mental foramen.
-genial tubercle.
-Buccal vestibule
-Lingual frenum
-Alveololingual sulcus
-Retromolar pad
-Mylohyoid ridge.
-Torus
mandibularis.
Labial frenum
Is a fold of mucous membrane at
the median line.
It divides the labial vestibule into left
and right labial vestibule.
It is recorded as a notch in the
impression made.
Labial vestibule
The labial vestibule is divided into left and
right labial vestibule by the labial frenum.
The mucous membrane lining the labial
vestibule is relatively thin and is classified as
lining mucosa.
The mentalis muscle is particularly active in
this region.
Buccal frenum
The buccal frenum forms the dividing line
between the labial and buccal vestibule.
Frenum may be single or double, broad U
shaped or sharp V shaped.
It should be relieved to prevent denture
displacement during function.
Buccal vestibule
The buccal vestibule extends posteriorly from the buccal
frenum to the outside back corner of the retromolar pad.
The impression is widest in this region.
The extent of buccal vestibule is influenced by the
buccinator muscle, which extends from the modiolus
anteriorly to the pterygomandibular raphe posteriorly
Retromolar pad
Definition – “A mass of tissue comprised
of non-keratinized mucosa located
posterior to retromolar papilla and
overlying loose glandular connective
tissue”. (GPT8)
This is the most distal extension of attached
keratinized mucosa overlying the mandibular
ridge.
The glandular retromolar pad is basically a
mandibular extension of palatal glandular
mass.
Importance….
Alveolingual sulcus
This is the space between residual ridge and tongue. It extends from lingual
frenum to Retromylohyoid curtain.
Can be divided in three regions:
• Anterior region
• Middle region
• Posterior region
Note; Anterior alveolingual sulcus of both the sides together is called
sublingual crescent space.
Lingual frenum
It is a mucosal fold which originates at the midline of
under surface of the tongue.
it crosses and bisects the sublingual crescent space and
attaches onto the lingual aspect of mandibular ridge.
Anatomical landmarks of supporting
structures in mandibular region
The Buccal shelf area
The area between the mandibular buccal frenum and the anterior edge of
the masseter muscle is the buccal shelf area.
Boundaries•
•
•
•
Medially- crest of RAR
Anteriorly- buccal frenum
laterally- external oblique ridge
Distally- retromolar pad
This area may be very wide and is at right angles to the vertical occlusal
forces. For this reason it offers excellent resistance to such forces and
hence a primary stress bearing area.
Residual alveolar ridge
The crest of the residual alveolar ridge is covered by fibrous connective
tissue, but in many mouths the underlying bone is cancellous and without a
good cortical bony plate covering it.
Because underlying bone is often cancellous (bony spicules and nutrient
canals), the crest of the residual ridge may not be favorable as the primary
stress-bearing area for a lower denture. Anteriorly if crest is thin and knife
edge it has to be relieved.
The slopes of alveolar ridge is considered as stress bearing areas.
Anatomical landmarks of Relief areas in
mandibular region.
Mental foramen
As resorption takes place, the mental foramen will come to lie closer to the
crest of ridge.
In these circumstances, the mental nerve and blood vessels may be
compressed by denture base unless relief is provided. Pressure on mental
nerve can cause numbness of lower lip.
Genial Tubercles
Like the mental foramina, the genial
tubercles usually lie well away from the
crest of the ridge but with resorption
genial tubercles become increasingly
prominent.
Mylohyoid ridge
Soft tissue usually hides the sharpness of mylohyoid ridge.
Anteriorly, this ridge with mylohyoid muscle is close to inferior surface of
mandible.
Posteriorly, after resorption, it often flushes with the residual ridge.
The mucous membrane overlying the sharp or irregular mylohyoid ridge
needs to be relieved.
Torus Mandibularis
Torus mandibularis is a bony prominence
usually found bilaterally and lingually
near the first and second premolars
midway between the soft tissues of the
floor of mouth and crest of alveolar ridge.
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