prosthetic consideration, histology of oral mucous membrane and gingiva.

1. HISTOLOGY OF ORAL MUCOUS
MEMBRANE AND GINGIVA
Vinay Pavan Kumar .K
1st year MDS
AECS Maaruti College of Dental Sciences

2. HISTOLOGY OF ORAL MUCOUS
MEMBRANE AND GINGIVA
Definition
Functions Classification
Structure
Organization
Histology of
gingiva
Prosthetic
consideration
Biological width

3.  The oral cavity is in many respects a very
interesting part of the human body .
 Many different kind of tissue from the hardest
teeth to the softest, the salivary glands are
found therein.
 The oral cavity is lined with an uninterrupted
mucosa which is continuous with the skin near
vermillion border of the lips and with the
pharyngeal mucosa in the region of soft palate
INTRODUCTION

4. Functions of oral mucosa
Protection :
Barrier for mechanical trauma and
microbiological insults
Sensation :
Temperature (heat and cold), touch, pain,
Reflexes such as swallowing, gagging and
salivation
Absorption :
Nitrates are absorbed sublingually

5. Secretion:
Salivary secretion creates a moist oral
cavity helps in speech, swallowing,
mastication and in the perception of taste.
Thermal regulation:
Important in dogs not in humans
Excretion:
excretion of certain metabolites
Esthetics :
Lips and gingiva enhance facial esthetics

6. Classification of oral mucosa
Based upon primary function served
1. Masticatory Mucosa (25%)
2. Lining Mucosa (Covers 60% of total area)
3. Specialised Mucosa (15%)
Based upon keratinisation
1. Keratinised
Orthokeratinized
Parakeratinized
2. Non-keratinised.

7. Based upon Location
1. Buccal Mucosa.
2. Lingual Mucosa.
3. Palatal Mucosa.
4. Labial Mucosa.
5. Alveolar Mucosa.


8. Structure of Oral Mucosa
Epithelium
Lamina Propria.
Submucosa

9. Epithelium
Epithelium of the oral mucosa is stratified squamous
epithelium.
It may be
1.Keratinized
2.Non keratinized
Keratinized layer
 ortho keratinized
 Para keratinized

10. Oral epithelium
Consists of two populations of cells:
Progenitor population
Maturing population
Progenitor cells function is to divide and
provide new cells
Maturing cells continually undergo a
process of differentiation or maturation to
form a protective layer

11. Amplifying CellsStem cells
Progenitor Cells
• Slow dividing
• Maintain basal cell layer
• Rapidly dividing
• Form other cell layers.

12. Turn over time
Skin : 52 – 75 days
Gut : 4 – 14 days
Gingiva : 41 – 57 days
Cheek : 25 days
Junctional Epithelium : 5 - 6 days
The time taken for a proginetor cell to pass through
the entire epithelial thickness and reach the surface

13. Keratinized oral mucous membrane

14. Keratinised Epithelium
(light microscopy)

15. Keratinised Epithelium
(Electron Microscopy)

16. Basal layer made of cell that synthesize DNA &
undergo mitosis.
Stratum Basale
Basal cells show ribosomes & elements of rough
endoplasmic reticulum indicative of protein
synthesizing activity.

17.  Structureless zone seen under
light microscope is basement
membrane.
 1 – 4 microns wide.
 Under electron microscope,
Basal lamina
 lamina lucida – light zone
 lamina densa – dark
zone

18. Basal cells are attached to basal lamina by
hemidesmosomes.
Epithelial cell-cell contact is made through
desmosomes - macula adherens. These are
anchored intracellularly by tonofibrils.

19. i) Serrated- heavily packed with tonofilaments
which are adaptations for attachment.
ii) Non-serrated – stem cells – slowly dividing
cells which serve to protect genetic information of
the tissue.

20. Stratum spinosum or prickle cell
layer:
It is a layer of relatively large irregular polyhedral
cells.
Show first sign of maturation.
Nuclei stains less intense the intercellular spaces of
the prickle layer are large and distended, with more
prominent desmosomes

21. Stratum granulosum
 Flatter & wider & nuclei show signs of degeneration &
pyknosis.

22. Active in protein synthesis.
 Involucrin - soluble precursor protein of the
cornified envelope appears first in the spinosum.
Protein synthesis rate progressively gets
diminished as cell approaches stratum corneum.
In the upper part cells of stratum granulosum,
shows granules called ODLAND BODIES.

23. Keratinosome or odland bodies or
membrane containing granules
Modified lysosomes
0.25µm in length.
Rich in phospholipids.
Structure - layers of parallel lamellae, probably
originating from golgi apparatus.
Lamellar granules discharge their contents -
permeability barrier.

24. Stratum corneum
Made up of keratinised squamae, which are
larger & flatter than the granular cells.
Nuclei & other organelles disappear.

25.  Cell surfaces in this layer are more regular &
more closely adapted to adjacent cell surfaces.
 The filaggrin a non fibrous inter-filamentous
matrix protien helps in this close adaptation.

26. Types of keratinized epithelium
Parakeratinized Epithelium :The superficial cells
are dead but retain the nucleus
Orthokeratinized Epithelium : The nuclei are lost
in epithelium

28. Non – keratinized epithelium
Nonkeratinized epithelial cells in the superfacial
layers do not have keratin filaments in the cytoplasm
The surface cells also have nuclei
This epithelium is associated with lining of the oral
cavity

29. Difference
Keratinized
Layers - basal, spinosum,
granular, cornified layer.
Produce a cornified
surface layer.
Prickly appearance.
Nonkeratinized
Layers-basal,intermediate,
surface layer.
Do not produce a cornified
surface layer.
Intercellular spaces not
obvious-no prickly
appearance.

30. No nuclei-orthokeratinised
Pyknotic nuclei-
parakeratinised
Filaggrin present.
Numerous
tonofilaments,keratohyaline
granules present.
Lack filaggrin,but contain
involucrin.
Less developed and
dispersed tonofilments,lack
keratohyaline granules.
Stratum superficiale
contains nucleated cells

31. Lamina Propria
Two Layers
 Papillary layer
Close to epithelial ridges.
Arranged loosely.
 Reticular layer
Parallel to epithelium.
Fibers are very thick.
Consists of cells , blood vessels, neural elements &
fibers embedded in amorphous ground substance.

32. Cells found in lamina propria
Fibroblast
Histiocytes
Macrophages
 Mast cell
 Polymorph nuclear leucocytes
Lymphocytes
Plasma cells
Endothelial cells

33. Submucosa
It attaches the mucous
membrane to the
underlying structures –
muscle or bone
 loose or a firm attachment
and consists of glands,
blood vessels, nerves, &
adipose tissues.
connective tissue of
various thickness

34. Nonkeratinocytes
Langerhan’s cells:Dendritic cells.
Merkel cell: touch receptors
 Melanocytes: melanin systhesis
 Inflammatory cells

35. Organization of the Oral Mucosa
3 types according to function:
Masticatory Mucosa:25% of total mucosa.
Lining Mucosa:60% of total mucosa
Specialized Mucosa:15% of total mucosa.

36. Lining mucosa
Covers the floor of mouth, ventral (underside)
tongue, alveolar mucosa, cheeks, lips and soft
palate.
Lip
Lip is covered by lining mucosa

37. Vermilion border
Junction between the skin and mucous membrane
of the lip

38. Floor of the mouth
Loosely attached to the underlying structures
Submucosa – adipose tissue

39. Ventral surface of the tongue
The mucous membrane is tightly bound to the
muscle bundles of the tongue smooth and relatively
thin

40. Cheek
Submucosa contains fat cells and small mixed
salivary glands

41. Mucosa of the Tongue - Specialised
mucosa
Anatomical division
It is divided into two parts by a V-shaped groove
known as sulcus terminalis.
Anterior 2/3rd or papillary portion or body of the
tongue contains lingual papillae.
Posterior 1/3rd is lymphatic portion or base of the
tongue contains lingual tonsil.

42. The different papillae found on the dorsal surface of
the tongue are:
1. Filliform papillae
2. Fungiform papillae
3. Circumvallate papillae
4. Foliate papillae

43. 1. Filliform papillae
Pointed extensions of the
keratinized epithelial cells
Most numerous papillae of the
tongue
Not associated with taste buds
Scanning electron micrograph
of Filliform papillae(arrow)

44. 2. Fungiform papillae
Fewer than the filliform papillae and are scattered
over the dorsal surface of the tongue
Rounded elevations above the surface of the tongue
Have taste buds on their superior surfaces
Not keratinized

46. 3. Circumvallate papillae
Located at the junction of the anterior two thirds (body)
and posterior one thirds (base) of the tongue
There are eight to twelve in number
Lined with taste buds and also openings of serous
glands
The secretion from the serous glands washes away
food for renewal of taste

48. 4. Foliate papillae
Located in the furrows along the posterior sides of
the tongue
Lined with taste buds
Not prominent in human beings

49. Taste Buds
They are small ovoid barrel shaped organs
40 micron thick and 80 micron high
Their outer surface is covered by flat cells
which surround a small opening called the Taste
Pore

50. Areolar mucosa
The areolar mucosa is a reddish-pink
tissue with blue vascular areas.
The epithelium is extremely thin non-
keratinized mucosa with a lamina propria

51. Hard Palate
Covered by masticatory mucosa
lateral regions of the posterior part contains
palatine glands

52. Gingiva
Covers the alveolar process of jaws and
surrounds the cervical portion of teeth.
It develops from the union of oral epithelium and
reduced enamel epithelium
Gingiva can be classified as
Free gingiva,
Attached gingiva and
Interdental papilla

53. Part of the oral mucosa
that surrounds the necks
of the teeth and forms the
free margin of the gingival
tissue
differentiated apically by
the free gingival groove
Free gingiva (marginal gingiva)

54. Attached gingiva
Between the free gingival groove and the
alveolar mucosa
The junction of the attached gingiva and the
alveolar mucosa is called mucogingival junction
 In healthy mouth attached gingiva shows
stippling

55. Interdental papilla
Appear in-between teeth apical to the contact
points
Valley like depression in the interdental papilla
called Col.

56. Gingival sulcus
Space or potential space between the tooth
surface and the free gingiva.
It is lined with sulcular epithelium
 Extends from free gingival margin to the
junctional epithelium.

57. Junctional epithelium
Forms the seal of the gingival epithelium and the
tooth
Floor of the gingival sulcus and extends apically
to the enamel of the tooth
Disturbances of epithelial attachment results in
deepening of the sulcus which is a sign of
gingival/periodontal disease

58. Sulcular epithelium
It is nonkeratinized.
No rete pegs in sulcular epithelium.
Sulcular epithelium is continuous With gingival
epithelium & the attachment epithelium

59. Gingiva contains dense fibers of
collagen:
Dentogingival : extends from the
cervical cementum into the lamina
propria of the gingiva.
Circular: small group of fibers
that circle the tooth & interlace
with other fibers.

60. Dentoperiosteal: fibers
can be followed from the
cementum into periosteum
of the alveolar crest & of
the buccal & palatal or
lingual surface of the
alveolar bone.
Alveologingival: fibers
arise from the alveolar
crest & extends into lamina
propria.

61. Biologic Width

62. Biologic width
The dimension of space that the healthy gingival
tissues occupy above the alveolar bone is the
biologic width.
Connective Tissue attachment + junctional
epithelium constitutes Biologic width
1.07mm +0.97mm= 2.04 mm
Any restoration should be atleast 3mm above
the alveolar crest to prevent the violation of the
biologic width.

63. Passive Eruption

64. Effect Of Aging On The Oral
Mucosa
 Epithelial thinning
 Decreased keratinization
 Less prominent rete pegs
 Decreased cellular proliferation
 Loss of submucosal elastin and fat
 Increased fibrotic connective tissue with
degenerative alteration in the collagen.

65. Prosthetic considerations

66. Behaviour of oral mucosa under
stress
Under compression behaves in a viscoelastic fashion.
Loaded epithelium demonstrates decrease in the
depth of epithelial ridges & connective tissue papillae
Care to be taken during impression procedures by
applying minimal pressures.

67. Tissue response
A. Recently made dentures:
Inflammation .
Soft tissue distortion.
Impingement of gingival margin.
Accumulation of dental plaque.
B. Dentures in use for > 1 year
Hyperkeratosis.
Scarring of tissue in border area.
Gross tissue distortion.

68. Soft tissue changes in oral mucosa
due to prostheses
soft tissue hyperplasia
fibrous hyperplasia.
epulis fissurata.
papillary hyperplasia.
inflammatory process under denture bases
denture stomatitis.
Candidiasis.
ulcerative lesions
angular chelitis.

69. Soft tissue hyperplasia
Rolls of hyperplastic tissues under denture
base
Due to bone resorption, with lesion filling the
space under denture base.
Develops slowly, painless.
 Surgical removal.
New dentures.

70. Papillary hyperplasia
 Granular type of inflammation
seen in palatal region.
Numerous papillary projections
give a warty appearance.
They show precancerous
tendencies.
 Discontinue denture wearing.
 Surgery.
 New dentures

71. Epulis Fissuratum
It is a pathologic condition that
appears in the mouth as an
overgrowth of fibrous connective
tissue.
Also known as inflammatory
fibrous hyperplasia, denture
epulis and denture induced
fibrous hyperplasia.
It is mainly caused due to ill
fitting dentures

72. Denture stomatitis
Chronic inflammation
Ill fitting denture.
Nocturnal denture wearing.
Hypersensitivity.
Poor oral hygiene.
Infections –Candida
albicans.

73. Candidiasis
 Debilitated patients.
Systemic disease such as
diabetes.
Unhygienic conditions.
- Discard the existing
denture.
- Anti fungal therapy
- New dentures.

74. Angular chelitis
SIGNS
Bilateral lesion that develops at the angle of
the lips.
Deep fissure or crack may be seen.
Appear ulcerated.
Exudatve crust may be present.
Anti fungal therapy.

75. Denture bearing area
Points to be considered while fabrication of
denture:
 Selective placement of forces by denture
base on supporting tissues.
 Form and placement of denture borders to
accommodate normal function.

76. Selective placement of force can be achieved by
employing different impression techniques
depending on the patients oral condition
Minimal pressure technique/Mucostatic
technique .
Selective pressure technique.
Pressure / Muco-compressive technique.

77. Crest of the residual ridge
(maxillary)
Firmly attached to the bone.
Keratinized epithelium.
Dense collagen fibers .
Sub mucosa – fat or glandular
cells.
Primary support for denture.

78. Palatine rugae
 Irregularly shaped rolls of soft
tissue in the anterior part of
hard palate.
 Clinical considerations
 Secondary stress bearing area.
 Resists forward movement of denture.
 Tissue rebound phenomenon.
 Maxillary major connector should end into
depressions between the rugae.

79. Mucous membrane of hamular notch
Space between the posterior part of
the maxillary tuberosity & pterygoid
hamulus.
It is thick and made of loose areolar
tissue.
 Marks the distal end of
denture.

80. Buccal shelf area
Partially keratinized.
Loosely attached.
Bone – compact bone.
Clinical implication
Impression should cover
the entire available area.

81. Slope of the residual ridge
(mandibular)
Keratinized epithelium .
When the soft tissue is
movable in the crest of the
ridge ,impression should be
recorded in its resting position.

82. F.P.D & oral mucosa
Sub gingival finish
 esthetics.
 old restoration extending into the
intracrevicular space.
 Insufficient vertical length or height
Margins should be smooth with proper
fit.

83. Esthetics & oral mucosa
Case of Altered passive eruption(APE)

84. Implants and Biological width
It has been found that the biological
width need not be a vertical
dimension but can have a horizontal
component.
Platform switching provides this
horizontal distance and so preserves
the crestal bone.

85. CONCLUSION

86. References

Ten Cate A R, Oral histology development,structure
and function, 5th edition, India, Mosby, 1999, pp 345-
385.
Kumar G S, Orban’s oral histology and embryology,
12th edition,India, Elsevier,2006, pp 210-257
Zarb G.A, Bolender C L, Prosthodontic treatment for
edentulous patients, 12th edition, India, Elsevier, 2004,
pp 84-86, 211-223,233-241
Avery J K, Oral development and histology, 3rd edition,
New York, Thieme, 2002, pp 243-252.