ANATOMICAL LANDMARKS OF EDENTULOUS MAXILLA

Stress Bearing Areas, Relief Areas and Limiting Areas of Edentulous Maxilla

1. Maxillary
Anatomical
Landmarks
Dr.Aamir Godil
Department of Prosthodontics
M.A.R.D.C.

2. Contents
•Introduction
•Terminologies
•Classification
•Stress bearing areas
•Reliefareas
•Limiting areas
•Musculature
•Summary
Completely edentulous maxillary
ideal cast

3. Maxillary residual ridge
Edentulous maxillary and
mandibular residual alveolar
ridges in frontal view
Edentulous maxillary residual
alveolar ridges in occlusal view

4. Maxillary completely edentulous cast
Anatomic portion
Art portion
Land
Heel

5. denture basal seat
bone mucous
membrane
mucosa submucosa
nerves
blood
vessels

6. Anatomical
landmarks
of maxilla

7. Terminologies
Stress bearing area
•the surfaces of oral structures that resist forces, strains, or
pressures brought on them during function
Relief area
•that portion of the dental prosthesis that is reduced to eliminate
excessive pressure
Limiting area
•that limiting boundary of a dental prosthesis

8. Stress bearing areas
•These are the load bearing areas. The denture should be
designed such that most of the load is concentrated on these
areas.
•Support is the resistance to the displacement towards the basal
tissue or underlying structures.
•It can be divided into :
i) Primary stress bearing area
ii) Secondary stress bearing area

9. Relief areas
•Relief areas are areas in the denture bearing area which
should be relieved during construction of the denture.
•They are either resorbed under constant load , having
fragile structures within or covered by thin mucosa which
can be easily traumatized

10. Limiting areas
•These are the sites that will guide us in having an
optimal extension of the denture so as toengage
maximum surface area without engaging upon the muscle
action.
•Encroaching upon these areas will lead to dislodgement
of the denture and/or soreness of the area while failure
to cover the areas up to the limiting structure will
decrease retention, stability and support of the denture.

11. Anatomical landmarks
The clinical application of this knowledge
determines:
1.Selective placement of forces by the
denture bases upon supporting tissues
2.Form of denture borders that will be
harmonious with the normal functioning
of the limiting structures that surround
them.

12. Classification
Maxillary Landmarks
Stress
bearing
Primary
Postero-lateral
slopes of hard
palate
Residual
alveolar
ridge
Secondary/
Support
Rugae
Maxillary
tuberosity
Relief
Incisive
papilla
Median
palatine
raphe
Torous
palatinus
Sharp spiny
processes
Cuspid
eminence
Zygomatic
process
Limiting
Labial
frenum
Buccal
frenum
Labial
vestibule
Buccal
vestibule
Hamular
notch
Vibrating
line
Fovea
palatine

13. Stress
bearing
areas
Of edentulous maxilla

14. Stress bearing areas
Rugae
Crest of residual
alveolar ridge
Poster0-lateral
slopes of hard
palate
Maxillary
tuberosity

15. Postero-lateral slopes
of hard palate
I)Macroscopic anatomy:
•Formed by palatine processes of
maxillae along the midline
•They support the soft tissues that
increase the surface areas of basal
seat
Postero-lateral slopes of
hard palate

16. Postero-lateral slopes of hard
palate
II) Macroscopic anatomy:
•Mucous membrane:
•Keratinized throughout yet varied
•Submucosa:
•Antero-laterally: adipose tissue
•Postero-laterally: glandular tissue
•Bone:
•Crest: compact in nature with haversian system
Antero-lateral
Adipose tissue
Postero-lateral
Glandular tissue

17. Postero-lateral slopes of hard palate
II) Microscopic anatomy of mucous membrane:
•Keratinized throughout yet varied
•Submucosa:
oAntero-laterally: adipose tissue
oPostero-laterally: glandular tissue
If these tissues are not
recorded in resting condition
Displaced tissues tend to
return to their normal form
Unseating forces on denture
Soreness
secretions from
palatal glands+

18. Residual alveolar
ridge
I) Macroscopic anatomy:
•Following extraction, sockets fill up
with new bone and the process of
remodelling and resorption
continues
•If the teeth are missing for years,
residual ridge may be quite small
and lack cortical bone
crest of residual alveolar
ridge
labial slopes of residual
alveolar ridge
buccal slopes of
residual alveolar ridge

19. Residual alveolar ridge
II) Microscopic anatomy:
•Mucous membrane:
•firmly attached to bone
•Thickly keratinized stratified squamous epithelium
•Thin submucosa is devoid of fat or glandular
cells + dense collagenous fibresin lamina propria
•Bone:
•Crest: compact in nature with haversian system
Tightly attached
mucosa
Compact bone+ =
Primary stress
bearing area
Bone
Periosteum
Submucosa
Mucosa

20. Residual alveolar ridge
Clinical considerations:
•Mucous membrane:
•If loosely attached to bone
oNon keratinized epithelium
oSubmucosa contains loose connective tissue and elastic fibres
•Bone:
•Crest: If resorbed, it cannot take up stresses
Loosely attached
mucosa
Resorbed
ridge
+ =Relief area

21. Rugae
I) Macroscopic anatomy:
•They are irregularly shaped rolls of soft
tissue in the anterior part of palate.
•They should not be distorted during
impression procedure since rebounding
distorted tissue tends to unseat the
denture
Rugae
Prominent rugae=Relief area

22. Maxillary tuberosity
I) Macroscopic anatomy:
•Low hanging tuberosity is complicated by
excess fibrous connective tissue.
•This tissue can prevent proper location of
occlusal plane if not removed.
•Rough and irregular bone could cause
irritation from denture base
Maxillary tuberosity

23. Relief
areas
Of edentulous maxilla

24. Relief areas
Incisive papilla
Mid-palatine raphae
Zygomatic process
Sharp spiny spicules
Torus palatinus
Cuspid eminence

25. Incisive papilla
I)Macroscopic anatomy:
•Incisive papilla covers the incisive foramen,
located on midline immediately between
central incisors
•It may have a variable position from one
individual to other
•The central location on the ridge indicates
the rate of resorption
Incisive papilla

26. Incisive
papilla
Nasopalatine
canal
Nerves Vessels
Note:
Incisive papilla: soft tissue
Incisive foramen: on bone

27. Significance of incisive
papilla
Midline landmark
Relief area: Overlies on the orifice of nasopalatine canal
Maxillary central incisors are placed 8 -12mm ahead of the incisive
papilla
Canine-Papilla-Canine (CPC) line: for arrangement of maxillary
canines
Mandibular incisors are placed 4 mm below the incisive papilla
Location of incisive papilla gives an indication of amount of
residual ridge and aids in determination of vertical height

28. Mid palatine raphae
•Location: junction of palatine processes of maxillae
•Coveredwiththinlayerofmucosa
Mid palatine raphae

29. Mid palatine raphae
•Mucous membrane:
•Mucosal layer is in contact with underlying bone
•Extremely thin submucosa
Non-resilient mucosa
Little of no stress over the raphae
during impression making
Denture will tend to rock over center
of the palate due to vertical forces
Non-resilient mucosa
Highly sensitive to excess pressure
Excruciating pain
Needs relief
Compact bone
Submucosa
Mucosa

30. Torus palatinus
•A hard bonyenlargement in the midline
of palate is called torus palatinus
•Type 1: Entirely soft tissue: loose and
flabby
•Type 2: Bone covered with thin mucosa
•Providing relief to larger tori may
compromise stability of denture
•Surgical reshaping may be required in
larger tori
Torus palatinus

31. Sharp spiny spicules
•Spiny processes on maxillary and palatal
bones deeply covered with soft tissue
•In resorbed ridge, these spicules irritate
the soft tissue between them and denture
base
•The canal leading from posterior palatine
foramina often has sharp overhanging
edge which may cut and irritate palatal
soft tissue due to pressure from denture
Sharp spiny spicules

32. Cuspid eminence
Cuspid eminence
•Protruding bony ridge around maxillary canine
•Significance:severeprominence mustbeprovidedrelief

33. Zygomatic process
•It is close to residual alveolar ridge in
malar region because of excess amount of
resorption of alveolar ridge.
•It is thinly covered by mucous membrane.
•May cause soreness if not adequately relieved
Zygomatic process
Location:
opposite first
molar

34. Limiting
areas
Of edentulous maxilla

35. Limiting areas
Labial frenum
Labial vestibule
Buccal frenum
Buccal vestibule
Anterior vibrating
line
Posterior vibrating
line
Fovea palatini
Hamular notch

36. Labial frenum
Labial frenum
•Fold of mucous membrane at median line
•No muscles
•Band of tissue starts superiorly in a fan shape
•Labial notch in the labial flange should be just wide and
deep enough to pass through it without manipulation of lip.
•Also, the denture flange should have lower thickness around
the frenum and can be beaded.

37. Buccal frenum
•Sometimes single fold of mucous membrane,
sometimes double.
•Requires more clearance than labial frenum
•Muscle attachments:
•Levatorangulioris(caninus): beneath
•Orbicularis oris: pulls the frenum forwards
•Buccinator: pulls the frenum backwards
Buccal freni

38. Buccal frenum
•The buccal frenum is a part of
continuous band of tissue going from
modiolus in the corner of the mouth
to buccal frenum on mandible
•Inadequate relief of frenum or excess
thickness of flange distal to buccal
notch can cause dislodgement of
denture when cheeks move
posteriorly

39. Labial vestibule
•a space lined by a thin mucous
membrane, extends on both sides of
the arch from the labial frenum to
buccal frenum
•Boundaries:
•Externally: upper lip
•Internally: residual ridge in edentulous
mouth
Labial vestibule

40. Buccal vestibule
•It extends from buccal frenum to hamular notch.
•Provides space for the buccal flange of the denture.
•Size varies due to:
•Contraction of buccinator muscle
•Position of mandible
•Amount of bone lost from maxilla
Buccal vestibule

41. Microscopic
anatomy of
vestibule
•Relatively thin and non
keratinized epithelium
•Submucosa:
•Thick
•Loose areolar tissue
•Elastic fibres
•Tissues are easily
movable
Labial and buccal flanges of
upper impression can be
easily over extended

42. Buccal vestibule: distobuccal
•The distobuccal flange of denture must be adjusted
to accommodate the ramus, coronoid process and
masseter in function
•The flange should not be too thickor the ramus
will push the denture out of place during opening
and lateral movements of mandible
Buccal vestibule

43. Buccal vestibule: distobuccal
Buccal vestibule
Mandible
Forwards or
laterally
Width of disto-
buccal vestibule
reduces
Masseter
Contraction under
pressure
Width of disto-
buccal vestibule
reduces
Mandible
Wide opening
Obscures disto-
buccal
vestibule:
decieving

44. Fovea palatini
•They are indentations near the midline of
palate formed by coalescence of several
mucous gland ducts
•They are close to vibrating line and are
always in soft tissue
•Ideal guide for location of posterior
border of denture
Fovea palatini

45. Hamular/ pterygomaxillary notch
•Situated between the tuberosity of
maxilla and hamulus of medial
pterygoid plate
•It is boundary of posterior border of
maxillary denture
•The posterior palatal seal is placed
through the centerof deep part of
hamular notch
•No muscles, no ligaments
Hamular notch

46. Hamular/ pterygomaxillary notch
Significance:
•Overextended denturewillcause
impingement on pterygopalatine
raphae(extending from pterygoid
hammulus to retromolar pad)
•Lacerationswill lead to trismus
Hamular notch

47. Vibrating lines
•The vibrating line is an imaginary line
drawn across palate that marks the
beginning of motion in soft palate when
the patient says “ah”
•Posterior and anterior
•Posterior vibrating line is always on
soft palate
•Shape varies according to anatomy of
palate
•Distal end of upper denture must
extend atleastto posterior vibrating
line (1-2 mm posterior)
Vibrating lines
anterior
posterior

48. Microscopic anatomy of
vibrating lines
•Submucosa
•Glandular tissue
Secretions from glandular tissue affects the
choice of final impression material
Soft palate does not rest directly on bone
Few mm on either side of vibrating line can be
repositioned on impression to achieve posterior seal

49. Posterior palatal seal
Posterior palatal seal: that portion of the
intaglio surface of a maxillary removable
complete denture, located at its posterior border,
which places pressure, within physiologic limits,
on the posterior palatal seal area of the soft
palate; this seal ensures intimate contact of the
denture baseto the soft palate and improves
retention of the denture
Synonyms:postpalatalseal
Posterior palatal seal
Glossary of Prosthodontic Terms -9

50. Posterior palatal seal
•Posterior palatal seal area: the soft tissue area
limited posteriorly by the distal demarcation of
the movable and non -movable tissues of the soft
palate and anteriorly by the junction of the hard
and soft palateson which pressure, within
physiologic limits, can be placed; this seal can
be applied by a removable complete denture to
aid in its retention
Posterior palatal seal
Glossary of Prosthodontic Terms -9

51. Parts of
posterior
palatal
seal

52. Posterior palatal seal
•Functions of PPS:
Retention
Reduces
patient
awareness
Reduces food
accumulation
Enhances
patient
comfort
Compensates
for
volumetric
shrinkage

53. Related
Anatomy
Muscles around maxilla

54. Muscles around the mouth

55. Anatomy
of
mouth
Descending palatine
artery
Mucous glands
Levatorvelipalatini
Residual alveolar
ridge
Buccinator
Pterygomandibular
raphae
Superior constrictor
of pharynx
Palatoglossus
Palatopharynx
Uvula

56. Muscles
of soft
palate
Sagittal view:
A-Levatorvelipalatini
B-Tensor velipalatini
C-Pharyngopalatinus
D-Uvula

57. Summary
Stress bearing areas Relief areas Limiting areas

58. References

59. Thank you