intro to dentures, removable prosthodontics, shammasm

2. ORAL ANATOMY IN RELATION
TO COMPLETE DENTURE
PROSTHODONTICS

3. Learning outcomes
1. Describe what are relief areas, support
areas and stress bearing areas.
2. Name the maxillary edentulous
anatomical landmarks.
3. Name the mandibular edentulous
anatomical landmarks.
4. Memorize the primary and secondary
stress bearing areas of maxilla and
mandible.

4.  In order to properly construct a
denture, one must understand
the anatomy and physiology of
the edentulous patient’s mouth.

5.  A thorough knowledge of the
origins and functions of the
muscles of mastication, facial
expression, tongue and floor of
the mouth is essential.

6. When the key anatomic
landmarks and their role with
respect to retention, stability,
support are mastered, dentures
can be fabricated as important
parts of each patient’s oral cavity
and not just mechanical artificial
substitutes.

7. EDENTULOUS ANATOMY

8. Relief areas
 The reduction or elimination of
undesirable pressure or force
from a specific region under a
denture base.

9. Support areas
 Those areas of the maxillary
and mandibular edentulous
ridges that are considered best
suited to carry the forces of
mastication when the dentures
are in function.

10. Stress bearing areas
 The surfaces of oral
structures that resist forces,
strains, or pressures brought
on them during function.
 Primary stress bearing area
 Secondary stress bearing
area

11.  The primary stress-bearing areas
generally have thicker mucosa
and /or underlying bone that is
less subject to resorption because
it is cortical bone.

12. The residual ridge is generally a
secondary stress-bearing area as it
is made up of cancellous bone.

13. Maxilla-Anatomic Landmarks

14. Labial frenum
Labial
vestibule
Buccal
frenum
Labial Frenum
 The labial frenum is a fold of
mucous membrane and it does
not contain any muscle fibers.

15.  The dentures should be relieved away
from the frenum, to avoid irritation to
these folds and to prevent future
instability of the dentures.

16. Labial frenum
Labial
vestibule
Buccal
frenum
Labial Vestibule
 It runs from one buccal frenum to
the other on the labial side of the
ridge.

17. Labial frenum
Labial
vestibule
Buccal
frenum
Buccal Frenum
 The buccal frenum is a mucous
membrane fold that overlies dense
fibrous connective tissue and fibers of
the levator anguli oris muscle.

18. Hamular Notch
Buccal
Vestibule
Buccal Vestibule
 The buccal vestibule extends from
the buccal frenum to the hamular
notch.
Buccal frenum

19. Maxilla-Anatomic Landmarks

20. Alveolar (Residual) Ridges
Following full mouth extractions, the
alveolar ridges undergo major bony
changes, with the largest changes
seen on the mandibular arch.

21.  Studies indicate that the
mandibular ridge resorps
approximately four times as
much as the maxillary arch.

22.  The direction of mandibular
resorption is downward and
outward, while maxillary
resorption is upward and inward.

23. Alveolar (Residual) Ridges
Slopes of maxillary residual ridge and
most of hard palate are the primary
stress-bearing areas.

24. Posterior
Palatal Seal
Area
Tuberosity
Maxillary Tuberosity
The maxillary tuberosity is the
most posterior part of the alveolar
ridge; it lies distal to the position of
the last molar.

25. The maxillary tuberosity is
important from a denture
standpoint because it is
considered a primary stress-
bearing area.

26. Incisive papilla
Incisive Papilla
The incisive papilla is a small tubercle
located on the palatal side between
the two central incisors.

27. It overlies the incisive foramen,
through which the incisive nerve and
blood vessels exit.

28. Because of the sensitivity of this
structure, care must be taken when
inserting the maxillary denture to
relieve almost all pressure in this area.

29. The incisive papilla is a good
landmark when arranging teeth
because studies indicate that the
facial surfaces of the natural central
incisors, when present, were
approximately 8-10 mm anterior to the
middle of the incisive papilla,

30. and the tips of the canines were
approximately in line with the middle
of the incisal papilla.

31. Palatine
Rugae

32. The palatine rugae are irregular
mucous membranes that extend
bilaterally from the midline of the hard
palate in relation to the upper six
anterior and sometimes bicuspid
teeth.

33. They are secondary stress-bearing
areas.

34. Torus Palatinus
 When present, the torus palatinus is
a bony prominence of variable size
and shape, which is located in the
middle of the hard palate.

35.  The tissue overlying a palatal
torus is usually very thin. Care
must be taken during insertion
to relieve any pressure to the
torus caused by the denture.

36. Midpalatine Raphe
Midpalatine
raphe

37.  The midpalatine raphe is a line in
the middle of the mucosa of the
hard palate that overlies the mid-
palatine suture.
Midpalatine
suture
Hard palate

38.  The tissue in this area is very thin,
and any pressure from a denture will
not be tolerated by patients. Care
must be taken when inserting the
denture to provide necessary relief.
Midpalatine
raphe

39. Fovea Palatini
Fovea palatini

40.  The fovea palatini are two
depressions that lie bilateral to
the midline of the palate, at the
approximate junction between
the soft and hard palate.
Fovea Palatini

41.  They represent the sites of
opening of ducts of small mucous
glands of the palate.

42. Hamular Notch
hamular notch

43.  The hamular process is a bony
projection of the medial plate of the
pterygoid bone and is located distal
to the maxillary tuberosity.

44.  Lying between the maxillary
tuberosity and the hamular process
is a groove called the hamular notch.
hamular notch

45.  This notch is a key clinical landmark
in maxillary denture construction
because the maximum posterior
extent of the denture is the vibrating
line that runs bilaterally through the
hamular notches.

46. Vibrating Line

47.  The vibrating line is very important to
locate for proper construction of the
maxillary complete denture.

48.  The vibrating line can be considered
as the junction between the hard
and soft palates and is important
because it is the maximum posterior
limit to the maxillary denture.

49.  This line runs from about 2 mm buccal to
the center of the hamular notch on one
side of the arch, follows the junction of
the hard and soft palates across the
palate, and ends about 2 mm buccal to
the center of the opposite hamular notch.

50. Posterior Palatal Seal Area

51. T- burnisher
 The posterior palatal seal area is
very important in maxillary
complete denture fabrication and
must be identified and evaluated.

52.  It is the area of compressible
tissue located anteriorly to the
vibrating line and lateral to the
midline in the posterior third of
the hard palate.

53.  The distal extent of this area is the
vibrating line, while the anterior
border is unclear.

56. Mandible-Anatomic Landmarks

57. Histologically and functionally it is the
same as in the maxilla. It is a mucous
membrane without significant muscle
fibers.
Labial Frenum
Labial Frenum

58. Labial vestibule
It runs from one buccal frenum to the
other on the labial side of the ridge.
Labial Vestibule

59. Buccal Frenum
 The buccal frenum is a mucous
membrane fold that overlies dense
fibrous connective tissue and fibers of
the depressor anguli oris muscle.
Buccal Frenum

60. Buccal
Vestibule
Buccal Vestibule
 The buccal vestibule extends
posteriorly from the buccal frenum to
the posterior lateral aspect of the
retromolar pad.
Buccal frenum
Retromolar
pad

61. The buccal shelf is the primary stress-
bearing area of the mandibular arch.
The buccal shelf consists of thick cortical
bone and lies at right angles to vertical
occlusal forces.
Buccal
shelf
Buccal Shelf

63. It is an area bounded on the medial side
by the crest of the residual ridge, on the
lateral side by the external oblique ridge,
anteriorly by the buccal frenum, and
posteriorly by retromolar pad.

64. A triangular area of thick mucosa is
found distal to the last molar, on the
crest of the ridge, and is referred to
as the retromolar pad.
Retromolar Pad

65. It is composed of:
Loose connective tissue
Glandular tissue
Fibers of the temporalis tendon
Fibers of buccinator muscle
Fibers of superior constrictor
muscle
The pterygomandibular raphe

66. The retromolar pads should be
covered by the denture, and the
plane of occlusion is generally
located at the level of the middle to
upper-third of this pad.

67. Just buccal to the crest of the
mandibular ridge in the distal-buccal
corner of the arch is an area known
as the masseteric notch.
Masseteric Notch
Masseteric Notch

68. Masseteric Notch

69.  It is important in mandibular
denture fabrication because of
its influence on impression
making.
 It is formed by the actions of the
masseter muscle.

70. The ventral surface of the tongue
(undersurface) is anchored to the
floor by a mucous membrane fold
known as the lingual frenum.
Lingual Frenum
Lingual Frenum

71. Lingual Sulcus
 Space between the
residual alveolar
ridge and the
tongue.
 It extends from the
lingual frenum to the
retromylohyoid
curtain.

72.  Some patients will exhibit bilateral bony
prominences of the inner surface of the
mandible in the region of the premolar
teeth called the torus mandibularis.
Torus Mandibularis

73.  These prominences must usually be
removed prior to denture
fabrication.
Torus Mandibularis

74. Alveolar (Residual) Ridges
 The mandibular residual alveolar
ridge is the secondary stress-
bearing area.

75. Genial Tubercles
 These are bony midline lingual
projections and offer attachment to
genioglossus and geniohyoid
muscles.

76.  In patients suffering from atrophied
mandibles, the residual ridge
resorbs to the level of the genial
tubercles, which can be easily
palpated.
 The dentures should be trimmed
around the genial tubercles in those
cases.