This document provides an overview of the oral mucosa. It defines oral mucosa as the moist lining of the oral cavity, classified as masticatory, lining, or specialized mucosa. The functions of oral mucosa include protection, sensation, lubrication, thermal regulation, and permeability. It develops from ectoderm and endoderm and is organized into epithelium, lamina propria, and submucosa layers separated by the basement membrane. The epithelium undergoes keratinization or non-keratinization and contains various cell types. The lamina propria contains fibers, ground substances, fibroblasts, and other cells. Age changes and diseases can affect the structure and function of oral mucosa.

1. ORAL MUCOSA
BY : DR. DHARATI PATEL

2. CONTENT
• Definition
• Classification
• Functions
• Development of Oral Mucosa
• Organization
• Basement membrane
• Lamina Propria
• Oral Epithelium
• Types of Oral Mucosa
• Junctions in Oral Mucosa
• Age Changes
• Conclusion
• Reference

3. DEFINITION
• The moist lining of the oral cavity which is in
communication with the exterior surface of skin on one
end and esophagus on the other end is called oral
mucosa.
• Anteriorly continuous with the skin of the lip through
vermilion border and posteriorly it is continuous with
the mucosa of the pharynx.

4. CLASSIFICATION OF ORAL MUCOSA
• Gingiva and Hard palate
MASTICATORY MUCOSA – 25%
• Lips , Cheeks , Vestibular, Fornix , Alveolar Mucosa , Floor Of
Mouth And Soft Palate
LINING OF REFLECTING MUCOSA – 60%
• Dorsum of the tongue and Taste buds
SPECIALIZED MUCOSA – 15%

5. FUNCTIONS
• Protection
• Sensory
• Lubrication / Secretion
• Thermal regulation
• Permeability and absorption

6. DEVELOPMENT OF MUCOSA
The primitive oral cavity develops at about 26th day of
gestation
5-6 weeks: 2 layer of cells have formed lining oral cavity and
extra cellular reticular fibers begin to accumulate .
7 weeks: Circumvallate & foliate papillae first appear, followed by
fungiform papillae(Bradley et al 1972) and lingual mucosa forms
8 -9 weeks: Significant thickening occurs in the vestibular
dental lamina and palatal salves rise and close
8-12 weeks: capillary buds and collagen fibers are detected.

7. 10 week – filiform papillae become apparent
10-12 weeks: Future lining and masticatory mucosa shows some
stratifications and separation of the cells covering the cheeks area
and the alveolar mucosa which forms an oral vestibule
13- 20 weeks : Epithelium is fully developed and shows distinct
differentiation between each layer (Dale et al1979) and Difference
between cytokeratins of epithelia are evident
17-20 weeks: elastic fibers become prominent in connective tissue
Orthokeratinization does not occur until teeth erupt during
postnatal period.

8. Endoderm - Structure that
develops from branchial arch
e.g. tongue , epiglottis and
pharynx Ectoderm – palate , cheeks and
gingiva

9. ORGANIZATION OF ORAL MUCOSA
• Outer vestibule – Bounded by lips and cheek
• Oral cavity proper – separated from outer vestibule by alveolar
bone and gingiva

10. BOUNDARIES OF ORAL MUCOSA
• Superior border – formed by
hard and soft palate
• Inferior border – floor of the
mouth and base of tongue
• Posterior border – pillars of
fauces and tonsils
• Anterior and anterolateral
borders – by the lips and
cheeks

11. GENERAL FEATURES:
Colour
• More deeply colored, most obviously at lips
• Factors:
Concentration and state of blood vessels underlying
connective tissue
Thickness of epithelium
Degree of keratinization
Melanin pigmentation
• Clinical application – Normal healthy tissue – Pale pink
Inflamed tissues -
Red

12. Surface
• Have moist surface
• Absence of appendages
• Smoother and have few folds and wrinkles
• Papillae on dorsum of tongue
• Transverse ridges on hard palate – Rugae
• Clinical application – gingival stippling
linea alba

13. Firmness
• The lining mucosa of lips and cheeks – soft, pliable
• Masticatory mucosa (gingiva and hard palate) – firm and
immobile
Clinical implications:
• Local anesthetic injection
• Suturing
• Accumulation of fluid with inflammation

14. ORAL MUCOSA IN CHILDREN
• More red in colour
• Healing capacity is higher
• Relatively smoother and soft
• Sebaceous glands are almost absent
• Gingival stippling is absent – up to 3 years of age

15. Layers
Epidermis
Dermis
Keratinization
Orthokeratinization
Content of
dermis
Skin appendages (hair
follicle, sebaceous
gland, sweat gland)
Salivary glands are
Layers
Epithelium
Lamina Propria
Submucosa
Keratinization
Non keratinized
Keratinized (Ortho , para)
Content of
lamina Propria
Absence of skin
appendages
Layers
Epithelium
Lamina Propria
Muscularis
mucosa
Submucosa
skin Oral
mucos
a
Intestina
l
Mucosa

16. HISTOLOGY OF ORAL MUCOUS
MEMBRANE

17. COMPONENT TISSUE
ORAL MUCOUS
MEMBRANE
ORAL
EPITHELIUM
Stratified
squamous
LAMINA
PROPRIA
Connective
tissue
Separated by
BASEMENT
MEMBRANE

18. BASEMENT MEMBRANE
• The interface between the connective tissue and the epithelium
(Karring et al 1970).
• 1-4 µm wide and relatively cell free
• Stain – periodic acid-Schiff
• Contains - Mucopolysaccharides
• Promote differentiation, Peripheral nerve regeneration and
growth
• They tends to prevent metastases

20. MADE UP OF TWO ZONE
Lamina Lucida (clear zone) – just below epithelial cells
• 20-40nm wide glycoprotein layer
• Contains – Type IV collagen and antibody KF-1
• Shown to contain laminin and bullous pemphigoid antigen
Lamina densa (dark zone) – below the lamina Lucida
• Type VII collagen forms loops and inserted into lamina densa
• Type I and Type II collagen run through that loops
• Contains type IV coated with heparin sulfate in chicken wire
configuration

22. LAMINA PROPRIA – CONNECTIVE TISSUE
• Consist cells , blood vessels , neural elements , fibers embedded in
amorphous ground substances.
• Divide into two parts:
• Associate with epithelia
ridges
• Variable depth
Superficial
papillary level
• Immature argyrophilic
reticular fiber
• Net like arrangement
Deeper reticular
portion

23. Papillary layer
Reticular layer

24. FIBERS
• Lamina Propria consist 2 major type of fibers
Collagen
• Type I and type III in lamina Propria
• Type V in inflamed tissue
Elastic
• Responsible for elastic properties of fiber
• Abundant in the flexible lining mucosa
• Function – to restore tissue after stretching

25. GROUND SUBSTANCES
• Consist of heterogeneous molecular complex permeated by
tissue fluid
• Chemically subdivided into two groups – proteoglycans and
glycoproteins
Proteoglycans - Hyaluronan , Heparin Sulfate, Versican , Decorin
, Biglycan And Syndecan
Glycoproteins – branched polypeptide chain to which few simple
hexoses are attached .

26. FIBROBLAST
• Principle cells- throughout lamina Propria
• Responsible for maintaining tissue integrity – turnover
• Cigar shaped(fusiform) or star shaped (stellate) with long
processes that lie parallel to collagen fibers
• Nuclei – 1 or more nucleoli
• Low proliferation except in wound healing
• Participates in wound contractions
• In certain cases like gingival growth - fibroblast activated and
secret ground substances

27. MACROPHAGES
• Stellate or fusiform cell
• Smaller and dense nuclei , less granular endoplasmic reticulum,
cytoplasm contains lysosomes
Function:
• Ingest damaged tissue or foreign material
• Stimulate fibroblast proliferation
• 2 types – malenophages and siderophages

28. MAST CELLS
• Larger spherical / elliptical mononuclear cell
• Size of nucleus is small relatively
• Principle contents of granules – histamine and heparin
• Found in association with small blood vessels – play role in
maintaining normal tissue stability and vascular hemostasis

29. INFLAMMATORY CELLS
• Lymphocyte and plasma cells – observed in small number
scattered in lamina Propria
• Other inflammatory cells present in connective tissue –
following injury
• Acute conditions – Ploymorphonuclear leukocytes
• Chronic condition - lymphocytes , plasma cells , monocytes
and macrophages

30. Submucosa
• Separate the oral mucosa from underlying bone or
muscles
• a layer of loose fatty or glandular connective tissue
• contains major blood vessels, nerves and adipose tissue
• Minor salivary gland present
Mucoperiostium
• Submucosa is absent in gingiva and some parts of hard
palate
• Oral mucosa attached directly to periosteum
• Provides firm inelastic appearance

32. GLANDS
Minor salivary glands
• Located in submucosa and mucosa
• The opening of the ducts at mucosal surface
Sebaceous gland
• Lie in lamina Propria
• Less frequent – present in upper lip and buccal mucosa
• Produce fatty secretion – sebum – lubricate the surface
• Clinical important – appear as yellow spots called Fordyce’s
granules

33. ORAL EPITHELIUM
• Primary barrier between oral environment and deeper tissue
• Ectodermal in origin
• Stratified squamous epithelium – distinct layers
• Maintains structural integrity by process of continuous cell
renewal – mitotic division
• 2 type of cell population :
a) Progenitor cells – divide and provide new cell
b) Maturing cells – differentiate or mature to form a protective
surface layer

34. EPITHELIAL PROLIFERATION
• The progenitor cells are situated
• Basal layer in - thin papillae
• In lower 2-3 layer in - thick epithelia
• Studies indicate that progenitor compartment consist
2 functionally distinct subpopulation
• A small population of slowly cyclic stem cells : produce
basal cell and retain the proliferative potential
• A larger population of amplifying cells: increase number of
cells available for maturation

35. Cell division is a cyclic process
After cell division
Daughter cell recycle in
progenitor population
Enters the maturing
process

36. Mitotic activity affected by:
• Epidermal growth factor
• Keratinocyte growth factor
• Interleukin 1
• Transforming growth factors
• Time of the day
• Stress
• Inflammation
Clinical importance:
• Cancer chemotherapeutic drugs block this mitotic activity.
• Which develops oral ulcers which experience pain and difficulty in
eating, drinking and maintaining oral hygiene.

37. EPITHELIAL MATURATION
• Cells undergo a process of maturation as they are passively
displaced towards surface.
• Follows 2 main pattern: Keratinization and Non keratinization
EVENTS IN MATURATION
• The major changes involved are
Change in cell size and shape
Synthesis of structural proteins and Tonofilaments
Appearance of new organelles
Production of additional intracellular material

38. ULTRASTRUCTURE OF EPITHELIAL CELLS
It includes:
• Tonofilaments – filamentous strands
• Desmosomes – intercellular bridges
• Hemidesmosomes

39. TONOFILAMENTS – FILAMENTOUS STRANDS
• Chemically it represent a protein known as cytokeratins (Dale et
al 1975).
• They usually aggregated to form bundles – Tonofibrils
• There are 19 types of keratin according to their molecular
weight:
Lowest molecular weight (40kDa) – glandular epithelium
Intermediate molecular weight – stratified epithelium
Highest molecular weight(67kDa) – keratinized stratified
epithelium

40. CYTOKERATIN
• Intermediate filaments
• Diameter – 7 to11 nm
• Molecular weight – 40 to 200 kDa
• Types :
Type I – basic cytokeratins (1-8)
Type II – acidic cytokeratin(9-19)
• Functions :
• Form cytoskeleton of epithelium and maintain shape of cells
• Act as stress bearing structure
• Distribute force over wide area and provide mechanical
linkages

41. Distribution:
• K5 and K14 – Specific for stratified epithelium
• K1, K6, K10, K16 – Specific for keratinized type. Expressed
more in Orthokeratinized
• K6 & K16 – Characteristic of highly proliferative epithelium
(exception is junctional epithelium)
• K4, K13, K19 – Specific for Nonkeratinized type (lining
mucosa)
• K19 – Seen in Parakeratinized, not present in
Orthokeratinized

42. DESMOSOME
• Desmosomes : also called macula adherence – intercellular
bridges
• Lateral border of the cells – closely connected by desmosomes
• Circular or oval areas
• Adhering by specialized denser region - attachment plaques.
• Contains protein – desmoplakin and plakoglobin
• Other proteins known as desmogleins and desmocollins - from
cadherin family

44. HEMIDESMOSOMES
• Provide adhesion between epithelium and connective tissue
• It is a protoplasmic processes – projecting from basal surfaces
towards connective tissues
• Desmosome and hemidesmosems differs in their molecular
consistency
• Clinical application : when theses are disturbed like in
pemphigus there is epithelial or subepithelial splitting of
epithelium cells occur.

45. GAP JUNCTIONS AND TIGHT JUNCTIONS
Gap junction (nexus): is a region where membranes of
adjacent cells run closely together, separated by only a small
gap.
• Allow electrical or chemical communication between
cells.(communicating junctions)
• Seen occasionally in oral epithelium
Tight junction (occluding): Adjacent cells are apposed
so tightly as to exclude intercellular space

47. Layers
of
Epitheli
um
Keratinize
d
Gingiva and hard
palate
Orthokeratinized
Parakeratinized
Some gingival tissue
Non-
keratinized
Inner lining of cheek
Sublingual tissue
Floor of the mouth

48. KERATINIZED EPITHELIUM
Basal
layer
Prickle
layer
Granular
layer
Cornified
layer
• A single cell is part of each layer
• After mitosis – divide again or migrates and pushed
upwards
• Cells which migrate – keratinocytes
• More resistant to infections and irritation

50. KERATINIZATION
Certain biochemical and morphologic changes occurs in keratinocytes
formation of keratinized squama- a dead cell
filled with densely packed protein called keratin
Reaches the outer
surface, lose their
moisture and
desquamates

51. Turn over time – time taken for a cell to divide and
pass through the entire epithelium
• 52-75 days in skin
• 41-57 days in gingiva
• 25 days in cheek
• 4-14 days in gut
• Nonkeratinized epithelium > keratinized epithelium

52. BASAL LAYER (STRATUM BASALE )
• Single layer of cuboidal cells
• stratum germinativum
• Cells – synthesis DNA and undergo mitosis
• Ribosomes and reticulum – protein synthesis
• Site of cell division
Cells made of 2
populations
Serrated and
heavily packed with
Tonofilaments
Adaptations for
attachment
Non serrated -stem
cells
protect genetic
information

53. PRICKLE LAYER (STRATUM SPINOSUM )
•Spinous cells – irregularly polyhedral and larger
•Cells joined by intercellular bridges - desmosomes
•Intercellular space – glycoproteins ,
glycosaminoglycans and fibronectin
•Most active – protein synthesis

54. CLINICAL IMPORTANCE
• Acanthosis- Increase in thickness of prickle layer in
pathologic conditions
• Acantholysis – separation of cells due to loss of
intercellular substance
• monoclonal antibodies used to detect
carcinomas(epithelial tumor)

55. GRANULAR LAYER (STRATUM
GRANULOSUM)
• Flatter and wider cells
• Cells are more regular more closely applied to adjacent
cells
• 0.5 to 1 nm sized irregularly shaped granules–
Keratohyaline granules
• Nuclei shows – sign of degeneration and pyknosis

56. ODLAND BODIES OR
KERATINOSOMES
• Also called membrane coating granules – glycolipids
• Size – 250nm
• Originate from Golgi bodies
• Keratinized epithelium- elongated/ Non-keratinized
epithelium – circular
• discharge their contents in intercellular space (Squire
et al 1971)

57. INVOLUCRIN OR KERATOLININ
• Thickening of cell membrane - Cornified cell envelope
• Forms – highly resistant structure
• Located in chromosome Iq21
Crosslinking of
Involucrin, Periplakin
and Envoplakin –
forms a scaffold
On which Loricrin
and SPRP are added
Influx of calcium
and cell death occur

58. CORNIFIED LAYER (STRATUM CORNEUM)
• Cells are larger and flatter
• All organelles, nuclei and Keratohyaline granules – disappears
• Cross linkage of Tonofilaments by disulfide bonds - gives mechanical
and chemical resistance to this layer
• Keratinized cells – compact and dehydrated
• Acidophilic and amorphous
• Cells layer contains densely packed protein - keratin
• Cells undergo desquamation

60. • Keratosis – when keratinization occurs in a normally
Nonkeratinized tissue
• Parakeratosis – when normally keratinized tissue
becomes Parakeratinized.
•Factors affecting keratinization:
Smoking
Chronic Inflammation

61. NON-KERATINIZED EPITHELIUM
• Stratum basale
• Stratum intermedium
• Stratum superficial
layers
Lack number of – Tonofilaments and
Keratohyaline granules
Mitosis – Nonkeratinized epithelium >
keratinized epithelium

62. DIFFERENCE BETWEEN KERATINIZED AND NON KERATINIZED
EPITHELIUM

63. NON KERATINOCYTES
• Clear cells
• 10% of cell population
• No ability to keratinized

64. MELANOCYTES
• Formed from – neural crest ectoderm , found in epithelium at 11th
week of gestation
• Established contact with 30-40 keratinocytes
• Secretion – as melanin
• Store – as melanosomes
• Stain by
Dopa reaction
Silver staining
Mosan Fontana stain

65. PIGMENTATION OF ORAL MUCOSA
• Colour difference results from relative activity of
melanocytes.
• Pigmented lesions are:
• Nevus
• Melanoma

66. LANGERHANS CELL/
DENDTRIC CELL
• Form in bone and appear at 11th month in gestation
• Dendritic cell seen above basal layer
• Contains small rods or flask shaped granule : Birbeck
granule
• Stained by – gold chloride, ATPase, immunofluorescent
markers

67. MERKEL CELLS
• Derived from neural crest
• Situated in basal layer and Non dendritic
• Absent in lining mucosa
• Functions - Sensory and respond to touch

69. INFLAMMATORY CELLS
• Lymphocytes and polymorphonuclear leukocytes
• Leukocytes

70. INTERFA
CE
• Usually irregular
• Connective tissue papilla epithelial ridges
• Undulations - Masticatory mucosa > lining mucosa
• Importance
• increased a surface area of the attachment -to dissipate force over
greater area.

71. BLOOD SUPPLY
• Blood supply is rich and derived by arteries
• The arrangement is more profuse then skin
• Blood supply greatest in gingiva
• Clinical important – have rich anastomoses of arterioles and
capillary which contribute rapid healing after injury than skin
Large
Vessels
gives of
smaller
branch
Anastomos
e with
adjacent
vessels
Capillary
loops pass
into the
connective
tissue
papillae
Come lie
close to
basal layer

73. NERVE SUPPLY
• densely innervated
• innervation initiate and maintain voluntary and reflexive
activities
• Nerves – 2nd and 3rd division of trigeminal and afferent
fibers of facial (VII) , glossopharyngeal (IX) and vagus (X)
• Primary sensation - Warmth , cold ,touch , pain and taste
• Sensory nerve networks more developed in anterior than in
posterior region

74. •Specialized ending groups
• Messeiner’s corpuscle – touch
• Ruffini’s corpuscle – warmth
• Krause’s bulb (cold)
• Mucocutaneous end-organs.

75. Oral region Innervation
Upper lip and
vestibule
Infraorbital branch of maxillary nerve
Upper gingiva Anterior, posterior and middle superior alveolar nerve
Hard palate Greater , lesser and sphenopalatine nerve
Soft palate Lesser palatine nerve , tonsillar branch of
glossopharyngeal nerve
cheek Buccal branch of mandibular nerve , superior alveolar
branch of maxillary nerve
Lower lip and
vestibule
Mental nerve and buccal nerve
Anterior 2/3rd
tongue
Lingual branch of mandibular nerve
Posterior 1/3rd of
tongue
Glossopharyngeal nerve

76. PART - 2
SUBDIVISION OF ORAL
MUCOSA

77. Keratinized
Masticatory
mucosa
Hard palate
Gingiva
Vermilion
border of lip
Nonkeratinized
Lining mucosa
Soft palate
Ventral
surface of
tongue
Floor of the
cavity
Lips and
cheeks
Alveolar
mucosa
Specialized
mucosa
Dorsal surface of
tongue

78. MASTICATORY MUCOSA

79. HARD PALATE
• Tightly fixed to underlying periosteum – Immovable
• Pale Pink in color
• Lamina Propria – long papillae , dense network
• Different zones of hard palate –
Submucosa of
hard palate
Anterior part
filled with
adipose tissue
Posterior part
Filled with glands

80. INCISIVE PAPILLAE
• Formed of dense connective tissues
• Contains – oral part of vestigial nasopalatine duct
• Lined by simple or pseudostratified columnar epithelium
and rich in goblet cells
• Small mucous glands – open into lumen of ducts
• Jacobson’s organ
EPITHELIAL PEARS
• found in lamina Propria
• Remnants of epithelium formed in line of fusion of palatine
process

81. PALATINE RUGAE

82. GINGIVA
• extend from gingival sulcus to alveolar mucosa
• Coral pink in colour
PARTS OF GINGIVA
HISTOLOGY OF GINGIVA
• 75% Parakeratinized 15% Keratinized
10% Nonkeratinized
• Lamina Propria – dense connective tissue ,
lymphocytes, plasma cells and macrophages
• Papillae – long, slender and numerous
• More collagen fibers, Few elastic fibers and
more blood vessels

83. DIVISION OF GINGIVA
1. FREE OR UNATTACHED GINGIVA
2. ATTACHED GINGIVA
3. FREE GINGIVAL GROOVE
3. MUCOGINGIVAL JUNCTION
4. GINGIVAL SULCUS

84. • INTERDENTAL PAPILLAE
Occupies the gingival embrasure
• COL
• Central concave area (valley like)
• Covered by non-keratinized epithelium
• Highly susceptible and vulnerable to periodontal diseases
• INTERDENTAL GROOVES
Depression present between two adjacent teeth

85. WIDTH OF THE ATTACHED GINGIVA
• Keratinized gingiva - free gingiva = width of attached gingiva
• Incisors – Maxilla - 3.5 to 4.5mm
Mandible – 3.3 to 3.9mm
• Premolars – Maxilla – 1.9mm
Mandible -1.8mm
CLINICAL IMPORTANCE:
• Increases with age
• Increase in supra erupted teeth
• Decrease in loss of attachment

86. GINGIVAL SULCUS AND SULCULAR
EPITHELIUM
• “V” Spaced
• Depth – approximately at the level of free gingival groove on
outer surface
• Lining the gingival sulcus – Nonkeratinized , thin , stratified
squamous epithelium
• Express CK4
• Semipermeable

87. GINGIVAL SULCULAR FLUID
• Contains components of – connective tissue , epithelium,
inflammatory cells, serum and microflora
• Use as diagnostic/prognostic biomarker
• Amount – Healthy Sulcus – Very Small
Inflammation – Increase
• Actions – Cleansing of sulcus
Antimicrobial properties
Antibody activity

88. GINGIVAL FIBERS
• Dentogingival
• Alvelogingival
• Circular
• Dentoperiosteal
• Transseptal group

89. STIPPLING OF GINGIVA
• Elevation followed by depression
• Produce by elongated papillary layer of connective tissue
• They are functional adaptations to mechanical impacts

90. GUM PADS IN INFANTS
• Alveolar arches of an infant are called gum pads
• Covered by dnese layer of fibrous periosteum
• Each gum pads shows :
Dental Groove
Transverse Groove
Gingival Groove
Lateral Sulcus

91. GINGIVA IN CHILDREN
• More red in colour.
• Attached gingiva is more, flaccid and less stippled (Soni 1963).
• Unique characteristics:
Interdental clefts
Retrocuspid papilla
(Easley & Weis 1970)
• Bimstein E and Peretz B concluded that stippling was evident from
3 years of age and thereafter no particular change is observed.
Stippling was more evident in maxillary arch then mandibular
arch.

92. DIFFERENCE IN FEATURE OF CHILDREN AND
ADULT GINGIVA
Characteristic Children Adult
Colour Bright pink Coral pink
Surface Smooth Stippled
Gingival contour Thick and round Knife edge
Free gingiva Keratinized Nonkeratinized
interdental col
Attached gingiva Retrocuspid papilla Retrocuspid papilla not
present
Interdental gingiva Interdental clefts Not present
Sulcus depth 2.1-2.3mm 1.8-2mm
Alveolar mucosa Red , thin and vascular Pink
Periodontal ligament Wide Narrow
Collagen fibers Less differentiated More differentiated
Polypeptide chains Normal cross linking Tight cross-linked
Ground substance Low ration of collagen to
ground substance
Collagen to ground
substance ratio normal

93. • Derived from periosteal vessels or
branches of alveolar arteries
Blood supply of
gingiva
• Submental and submandibular lymph
nodes
Lymphatic
drainage of
gingiva
• Periodontal nerve fibers – infraorbital ,
palatine, lingual, inferior alveolar and
buccal nerves
Nerve supply to
gingiva

94. VERMILION ZONE
• Transitional zone - vermilion zone or red zone
• Divided into three zones
• In young person – demarcated sharply
• Exposed to UV radiation – diffuse and poorly defined.
• In infants this region is thickened and more
opalescent,
represents an adaptation to sucking – suckling pad.

95. NONKERATINIZED AREA

96. LIPS AND CHEEKS
• Stratified squamous Nonkeratinized
epithelium
• The cheeks firmly attached to underlying
buccinators and lips to orbicularis oris
• Lamina Propria
• Submucosa – lips
cheeks
• sebaceous glands

97. VESTIBULE AND ALVEOLAR MUCOSA
• Loosely attached to underlying structure and periosteum
• Papillae – low and often missing
• The median and lateral labial frenum
• Alveolar mucosa – dark in colour and Contain small mixed
glands

98. FLOOR OF THE CAVITY
• Mucous membrane- thin and loosely attached - Allow free
mobility of tongue
• Papillae – short
• Submucosa – adipose tissue
• Sublingual glands lie close to mucosa

99. INFERIOR SURFACE OF TONGUE
• Mucous membrane – relatively thin and smooth
• Papillae – short but numerous
• Submucosa can not be identified as separate

100. SOFT PALATE
• Mucous membrane – highly vascularized and
reddish in color
• Papillae – few and short
• Lamina Propria- distinct layer of elastic fibers and mucous glands
• Contains taste buds and mucous gland
• Latter replaced by nasal mucosa with pseudostratified ciliated
columnar epithelium

101. SPECIALIZED MUCOSA
Dorsal lingual mucosa
• Specialized mucosa
• Mucous membrane – moist , pink ,
rough and irregular

102. Divides into two part

103. PAPILLAE OF TONGUE
FILIFORM PAPILLAE
• Cone shaped structures
• Keratinized epithelium- with no taste bud
• Tough , abrasive , rough surface
FUNGIFORM PAPILLAE
• Mushroom like papillae.
• They are smooth, round and red
• They have non keratinized epithelium with
taste buds on superior surface (Farbman 1965).

104. FOLIATE PAPILLAE
• Present on the lateral margins of the posterior tongue
• Papillae consists of 4-11 parallel ridges
and few taste buds.
CIRCUMVALLATE PAPILLAE
• They are 8-12 in number
• contains taste buds (Mattern Et al 1970).
• Von Ebner’s gland open into it

105. TASTE BUDS
• Only specialized receptors in oral cavity
• Ovoid or Barrel shaped structure
• 50-80 in length and 30-50  in diameter.
• Composed of 30 to 80 spindle- shaped cells
• Extend from basal lamina to surface
• Taste pit or taste pore of 2-5  diameter
• Three types of cells
• Rich plexus of nerve – found below the taste buds

106. Generated
by
absorption
of
molecules
onto
membrane
receptor on
surface of
taste buds
Activates a
signaling
cascade
mediate by
transducin
and
gustaducin
Change in
membrane
polarization
Release of
transmitter
substance
Stimulate
unmyelinate
d afferent
fibers of
glossophary
ngeal
nerves (IX)
Mediated by membrane binding protein called gustaducin
and transducin

107. REGIONAL TASTE SENSATIONS

108. DIFFERENCE IN CHILDREN
Name of
structure
In children In adult
Hard palate Smooth and soft , rugae are
less
Densely attached
and more rugae
Periodontal
ligament
Wider space and few fibers Less wider and more
fibers
Alveolar
mucosa
More red Less red
Alveolar
bone
Less calcified , more
vascular , thin lamina dura
More calcified , less
vascular , thick
lamina dura

109. Junctions in
oral mucosa
Mucocutaneous Mucogingival Dento-gingival

110. MUCOGINGIVAL JUNCTION
• Between attached gingiva and alveolar mucosa called
Mucogingival junction
• Identified clinically by slight indentation – Mucogingival groove
• Pale pink – bright red
• Remains stationary for life
• Epithelium – keratinized – Nonkeratinized
• Lamina Propria – few elastic fibers – numerous
• Stippling – present to absent
• Firm nd resllient attachment to loose textured attcahmnets

111. DENTO-GINGIVAL JUNCTIONS
• Junction between gingiva and tooth
• Junctional epithelium
• Epithelial attachment
• Intermediate filaments found – CK- 5, 14,19
• Extend 2mm on the tooth surface
• Highest Turnover – 5-6 days
• Highly permeable
• Lessened resistance to – mechanical forces
and bacterial attack

112. DEVELOPMENT OF DENTO-GINGIVAL
SULCUS
Ameloblast leave a thin membrane on the
surface – primary cuticle
Then epithelial enamel organs reduced to
few layers of flat & cuboidal cells –
reduced enamel epithelium
As tooth erupts the REE merge and fuse
with the oral epithelium
Eventually shallow grove formed and
bordered by attachment epithelium at
base and laterraly with free gingival
mergin
With eruption , the REE moves apically
and reduced in length
As tip of the crown has emerged the REE
termed as primary attachment epithelium

114. SHIFTING OF DENTO-GINGIVAL JUNCTION
• Position of gingiva on the surface of tooth changes with the
time
Entire
enamel
covered by
epithelium
when tip
emerges to
oral cavity
As the
crown
continuous
emerges on
to the oral
cavity the
epithelium
separates
from the
enamel
surface
1/3rd or
1/4th of
enamel is
covered by
gingiva
when tooth
first
reaches the
plane of
occlusion
Slowly
exposure
of whole
crown
follows

116. PRIMARY
ATTACHMENT
EPITHELIUM
SECONDARY
ATTCHMENT
EPITHELIUM

117. APICAL SHIFT OF THE GINGIVAL SULCUS
• Stage -1
• Stage –II
• Stage- III
• Stage –Iv
Physiological
Probably pathological

118. AGE CHANGES IN ORAL MUCOSA
With age….
• Oral mucosa becomes smooth and dry
• Reduction in size and number of filiform papillae
• Varicose vein appears on ventral surface of tongue called
lingual varices
• Ectopic sebaceous glands appear

119. CLINICAL CONSIDERATION
• Periodontal pockets
• Cemental or root caries
• Cemental abrasion
• Restoration
• Edema
• Keratinization of gingiva
• Over hanging fillings
• Discoloration of gingiva

120. CONCLUSION
• Abnormality can only be detected when one knows what is
normal.
• By understanding normal histology of oral mucous membrane
any deviation from normal tissue can be easily recognized.
• Oral mucosa present unique structure and characteristics, a
clinician must know its normal variation in the structure &
function.

121. REFERENCES :
• Antonio Nanci, Oral Mucosa, Ch 12, Ten Cate’s Oral Histology,
Sixth Edition (Mosby Publications); 329-375.
• Carranza, Newman, Takei. The Gingiva, Ch 1, Carranza’s
Clinical Periodontology, Ninth Edition (Elsevier); 16-35.
• James Every, Histology of Oral Mucosa, Ch 14, Oral
Development and Histology, Third Edition (Thieme Publication)
243-262.
• S. N. Bhaskar, Oral Mucous Membrane, Ch 9, Orban’s Oral
Histology & Embryology, Tenth Edition (CBS publications); 253-
327.