ORAL MUCOUS MEMBRANE

2. Introduction
 The moist lining of the oral cavity that is in
continuation with the exterior surface of skin on one
end and oesophagus on the other end is called the oral
mucosa or oral mucous membrane.

3.  The oral cavity consists of 2 parts:
 outer vestibule (bounded by lips and cheek)
 oral cavity proper (separated by alveolus bearing teeth
and gingiva).
 Superiorly: hard and soft palate
 Inferiorly: floor of mouth, base of tongue
 Posteriorly: pillars of fauces, tonsils

4. CLASSIFICATION
 1. masticatory mucosa-gingiva, hard palate.
 2.lining or reflecting mucosa-lip, cheek , vesibule,
alveolar mucosa,floor of the mouth, soft palate.
 3.specialized mucosa-tongue.

5.  Masticatory mucosa bound to bone and do not stretch.
 Lining mucosa can stretch and do not bears forces of
mastication.
 Lining mucosa provide support to the chewing and
bears the forces generated by masticatory muscle.
 The specialised mucosa consist taste buds which have
sensory function.

6.  As in the skin oral mucosa consist of epithelium and
connective tissue.
 The connective tissue part of oral mucosa called as
lamina propria.
 Comparable part of skin is dermis.

7.  The two layers form an interface that is folded into
corrugations.
 Some nerves passes into the epithelium from the
connective tissue.

8.  Although continuous with skin, oral mucosa differs in
a number of ways.
 Colour: Oral mucosa is more deeply coloured, most
obviously at the lips.
 Concentration and state of dilatation of blood vessels.
Thickness of epithelium Degree of keratinisation
Amount of melanin pigment

9.  In gingiva and parts of hard palate, oral mucosa
directly attached to underlying bone. This provides a
firm inelastic attachment: Mucoperiosteum
 Minor salivary glands in submucosa Sebaceous
glands in lamina propria produce sebum said to
lubricate the surface of the mucosa

10.  The oral epithelium is a stratified squamous
epithelium consisting of cells tightly attached to each
other and arranged in a number of distinct strata.
 Maintains its structural integrity by a process of
continuous cell renewal

11.   Cells produced by mitotic divisions in deepest layers
replace those that are shed. Thus there are 2
populations of cells: A progenitor population A
maturing population.
 In thin epithelia, progenitor cells seen in basal layer
In thicker epithelia, seen in lower 2-3 cell layers

12.  Epithelium and connective tissue seperated by basal
lamina and basement membrane
 Basal lamina is epithelial origin while basement
memebrane is connective tissue origin.

13.  Some cells with heavy serrations provide attachment
to the epithelium.
 Some cells with flatter basal surfaces may be preparing
to undergo cell division.
 The resultant cell will either remain in proliferative
pool in the basal layer or will become determined as a
keratinocyte.
 cell slowly moves towards the surface of epithelium to
become the part of stratum corneum.

14. LAMINA PROPRIA
 Support the epithelium
 Divided into two parts
 a)papillary
 b)reticular
 The two parts are not separate.
 Reticular fibers more in reticular part.
 Sometimes papillary portion is absent.

15. SUBMUCOSA
 Attaches the mucosa to underlying tissue.
 It is loose or firm depends upon characteristic.
 Large artery divide into submucosa and enters into the
lamina propria.
 Small arteries forms sub epithelial plexus.
 Nerve loose their myelin sheath when enters into the
lamina propria.

16.  Some nerves ends into the papillary part and some
into the epithelium.

17. EPITHELIUM
 Stratified squamous type.
 May be keratinized.
 Para or orthokeratinised.
 Some times it is non keratinised.
 Distinguishing feature is keratin intermediate
filament.
 Analogus component of connective tissue cell is
vimentin.

18.  In muscle cells it is called as desmin.
 In nerve it is called as neural filament.
 All intermediate filament resembles tonofilament.
 Keratinised epithelium can be divided into four parts
1. Stratum basale
2. Stratum spinosum.
3. Stratum granulosum.
4. Stratum corneum.

19.  Cells migrate towards surface.
 After reaching the surface it desquamates.
 This whole process is known as keratinisation.
 For a healthy tissue it is necessary to undivided cell
remains in the basal layer.

20.  Serrated basal lamina or basal cell provide attachment
to the connective tissue.
 It is cuboidal , having hemidesmosomes.
 The basal lamina is made up of a clear zone (lamina
lucida) just below the epithelial cells.
 And a dark zone (lamina densa).
 The basal cells attached each other by desmosomes.

21.  The tonofilament and desmosomes are responsible for
attachment of each cells of epithelium and forms the
tensile supporting system to the epithelium.
 The presence of hemidesmosomes in basal layer is
higher in gingiva and palate as compare to alveolar
mucosa.
 The intercellular spaces in spinous cell layer is more
hence it is also called prickle cell layer.

22.  Spinous layer is more active and helps in protien
synthesis.
 The next layer st granulosum is larger than spinous cell
layer.
 Presence of keratohyaline granules.
 The nuclei shows signs of degeneration and pyknosis.
 The rate of protien synthesis is low as compare to
spinous.

23.  Tonofilaments are more dense.
 Keratinosome or odland body-it is lamellar granule
present in upper spinous and granular cell layer.

24.  The keratinised layer in oral cavity is composed of up
to 20 layers of squames.
 The tightly packed cytokeratins within an insoluble
tough envelope makes the layer resistant to
mechanical and chemical damage.
 The surface layer of nonkeratinised epithelium
consists of cells with loosely arranged filaments that
are not dehydrated.
 Thus they form a surface that is flexible and tolerant of
compression and distension.

25. ST. CORNEUM
 Larger and flatter than granulosum.
 Nuclei and ribosomes may be disappear.
 Cells are stained with eosin appears pink.
 It is packed with tonofilaments.
 Cells are coated with protein flaggrin.
 Epithelial cells that keratinized called as keratinocytes.

26. Non Keratinized Epithelium
 No st corneum layer.
 St basale, st intermedium, st superficiale.
 St basale are similar to keratinized epithelium.
 Cells of st. Intermedium are larger as compare to st
spinosum.
 No space present hence no PRICKLY appearance.
 Cells attached with desmosomes.
 No st grnulosum layer.
 No st corneum layer.

27.  Higher rate of mitosis then keratinising epithelium.
 Ortho and para keratinised layer differ in pycnotic
nucleus.

28. SUBDIVISIONS OF ORAL MUCOSA
 1)KERATINIZED AREA- masticatory mucosa,
vermilion border of lips.
 2)NON KERATINIZED AREA- Lining mucosa,
specialised mucosa.

29. KERATINIZED AREA
 Masticaory mucosa (gingiva and hard palate)-similar
in thickness, firmness, attach ment of lamina propria.

30. HARD PALATE
 Lamina propria is attached firmly hence immovable.
 It is pink like gingiva.
 More no of tonofilaments to bear forces.
 Anterior lamina propria is thicker then posterior.
 The palate can be divided into various zones.

31.  1. gingival region.
 2.palatine raphe.
 3.anterolateral area or fatty zone.
 4.posterolateral area or glandular zone.
 Peripheral part do not have submucous layer as in
gingiva.
 The submucosa of rest of the area is firmy attached to
the periosteum.

32.  Attachment by means of dense bands and trabaculae
of fibrous connective tissue.
 The submucosa of palate contains fat at anterior part
and glands in the posterior part.

33. INCISIVE PAPILLA
 Formed by dense connective tissue.
 Vestigial nasopalatine duct.
 Small mucous glands opens into it.
 Found in animal as jacobson;s organ but not in
human.

34. PALATINE RUGAE
 Irregular and asymmetric in humans.
 Anterior part of the palate.
 The core is made up of dense connective tissue layer
with fine interwoven fibers.

35. EPITHELIAL PEARLS
 In the midline specially in the region of the incisive
papilla sometimes there is presence of epithelial
pearls.
 Found in lamina propria.
 It is concentrally arrange epithelial cell with
keratinization.
 They are the remanent of epithelium formed during
fusion.

36. GINGIVA
 Extends from dentogingival junction to alveolar
mucosa.
 Bears masticatory forces.
 Most often the epithelium is parakeratinized.
 The collagen fibers of lamina propria either insert into
the cementum or periosteum of bone.
 Gingiva situated outer surface of both the jaws it is
limited by mucogingival junction.

37.  Gingiva ------free, attached and interdental papilla.
 Free gingival groove.
 Appears in histological sections.
 Ideally gingiva is stippled.
 At depression there is heavy epithelial ridges.
 Loss of stippling is sign of edema and gingivitis.
 In males stippling is more as compare to females.

38.  Gingiva depressed at the junction of two tooth forms
interdental grooves.
 Papilla is the part that fill the spaces between two
tooth.
 In anterior teeth it is triangular posteriorly it is tent
shape.
 Col- centeral part of the tent.
 Col is non keratinized.
 Vulnerable to periodontal disease.

39.  The gingival fibers of the pdl insert into the lamina
propria of the gingiva.
 Attaching the gingiva to the pdl.
 Gingiva is firmly attached to the bone hence it is called
as mucoperiosteum.

40. GINGIVAL FIBERS
 Sometimes called as gingival ligament.
 Collagen fibers.
 1. dentogingival
 2. alveologingival
 3. circular.
 4.dentoperiosteal.

41.  Dentogingival-cervical cementum into the lamina
propria.
 Alveologingival-from alveolar crest into the lamina
propria.
 Circular- circle the tooth.
 Dentoperiosteal-fom cementum into the periosteum
of alveolar bone.

42.  Also there are some fibers that extends interproximaly
known as transseptal fibers.
 These fibers forms interdental ligaments.
 Normal colour of gingiva is pink or raddish pink.
 Gingiva is parakeratinized in 75% of cases.
 Presence of melanin pigment gives it a brown or black
appearance.
 Highest at interdental papilla.

43.  Melanin is stored in the basal layer cells in the form of
melanosomes.
 Melanocytes comes into the surface layer.
 Melanocytes can be detected by dopa test or silver
staining technique.
 Langerhance cells
 Stains with gold chloride.
 No desmosomal attachment is seen in melanocytes as
well as in langerhance cells.

44.  Langerhance cells helps to eliminate bacteria at the
surface layers.
 It migrate into the gingiva.
 It is haemopoetic origin.
 It acts as a macrophages.

45.  Two types of clear cells are found in the epithelium-
melanocytes, langerhans giant cells.
 Thus oral mucous membrane provide protection of
oral cavity.
 Merkle cell in basal lamina is neural pressure sensitive
receptor cell.
 It is neurally related but no neural filaments.
 Lymphocytes and PMNL is also found and it is
migratory.

46. Blood and nerve supply of gingiva
 Alveolar arteries.
 At alveolus it anastomoses with small arteries and
supply the vestibular and rest of the gingiva.
 Gives branches namely lingual buccal palatine etc.
 Submental and submandibular lymph nodes.

47.  Nerve supply via meissners corpusles, end bulb, loop
and fine fibers that enters into the epithelium.

48. Vermilion border of lip
 Joint between lip and oral mucosa.
 Found only in humans.
 Skin of lip is thick with more keratinization and more
thick st corneum.
 Papilla is few and short.
 Sebaceous and sweat glands also found.
 The mucosa at the transitional zone is nonkeratinized.

49.  Transition zone have numerous long papilla and blood
vessels.
 It is appear red due to blood supply.
 Only have sebaceous gland thats why it require
additional moisure.

50. Non keratinizing area
 Lining mucosa-thick epithelium and thin lamina
propria.
 Differentiate by means of submucosa.
 Lining and reflecting mucosa.

51. LIP AND CHEEK
 The epithelium of lip and cheek is stratified squamous
non keratinizing type.
 Lamina propria have dense connective tissue with
short papilla.
 Submucosa attached to the fascia of the muscle.
 Prevents biting during chewing.
 The cheek lateral to the corner of the mouth may
contain isolated sebaceous gland called fordyce spots.

52. VESTIBULAR FORNIX AND ALVEOLAR
MUCOSA
 Lamina propria is loosly attached to the muscular
fascia hence provide movements.
 The mucous membrane of the vestibule is loosly
attached to the periosteum.
 Labial frenum is folds of mucous membrane with no
muscular attachment.
 Gingiva and alveolar mucosa is separated by
mucogingival junction.
 The epithelium is thin and nonkeratinized.

53. Inferior surface of tongue; floor of the
mouth
 Thin and loosly attached to the underlying structure to
allow the movement of the tongue.
 Epithelium is non keratinized.
 Lamina propria is short.
 Submucosa contains adipose tissue.
 Sublingual glands situated at the covering mucosa.
 Ventrolingual mucosa.

54. SOFT PALATE
 Highly vascularized hence reddish in colour.
 Papilla are few and short.
 Epithelium is nonkeratinized stratified squamous
type.
 The submucosa contains thick bands of elastic fibers.
 epithelium contains some taste buds.
 At some distance it is replaced by pseudostratified
ciliated columnar epithelium.

55. Specialized Mucosa
 DORSAL LINGUAL
MUCOSA-superior surface of
the tongue is rough with a V
shape line that divide the
tongue into anterior part or
body and posterior part or
base.
 Anterior two third and
posterior one third.
 Anterior by trigeminal and
posterior part by
glossopharyngeal.
 anterior and posterior
develops from two different
visceral arches.

56.  Oral mucosa of body and the base is different in
tongue.
 Anterior part- papillary.
 Posterior part-lymphatic part.
 On anterior part presence of numerous cone shaped
small papilla gives valvety appearance.
 These projectons are filiform papilla.
 It is epithelial structures.

57.  These epithelial
structures have core
made up of connective
tissue papilla.
 These are called
secondary papilla.
 The covering epithelium
is keratinized.
 Filiform papilla do not
contain taste buds.

58.  In between the filiform
papilla there is presence
of fungiform papilla.
 It is mushroom shaped.
 It contains taste buds but
only at the dorsal
surface.
 Usually there is two to
three taste buds.

59.  In between the body and
the base of the tongue at
the level of V shaped
groove there is presence of
eight to ten vallate papilla.
 It is not elevated but
found at the level of
tongue mucosa but it
contact with the fluid part
through its base.
 Secondary papilla are
covered with the thin
smooth epithelium.
 At the lateral surface it
contains taste buds.

60.  The ducts of small serous glands opens into the lateral
border known as von ebner;s gland.
 Main source of salivary lipase.
 Foliate papilla-lateral part of the posterior surface of
tongue. It is vestigial but some times found in humans,
contain taste buds.

61. TASTE BUDS
 Small ovoid barrel shaped
epithelial entity projects
from basal lamina to the
surface of epithelium.
 At the opening it is
surrounded by the some
epithelial cells that is flat in
nature.
 this opening is known as
taste pore.
 A taste buds have more than
one taste pore.
 It leads into a narrow space
lined by the supporting cells
of the taste buds.

62.  Outer arranged like a staves of a barrel and inner is
spindle shaped.
 Between the inner supporting cells there is presence of
neuroepithelial cells.
 Work as a receptor of taste stimuli.

63.  Different taste can be
tasted by different part
of tongue and palate.
 Sweet-anterior part(tip).
 Salty-lateral border.
 Bitter and sour-palate
and posterior part of
tongue.

64. Taste buds according to taste
 Vallate-bitter.
 Foliate- sour.
 Fungiform papilla-sweet.
 Fungiform at the lateral side for salty taste.
 Bitter and sour taste mediated by glossopharyngeal
nerve.
 Sweet and salty taste –intermediofacial nerve by
chorda tympani.
 Firing of the nerve.

65.  Foramen caecum-angle of the v shaped terminal
groove, remanent of thyroglossal duct.
 Lingual follicles-round oval prominence at the
posterior surface of the tongue contains lymph nodes.
 These follicles have central pit where lymphocyte can
migrate from omm.

66. Gingival sulcus and dentogingival
junction
 Invagination made by gingiva to the tooth surface.
 Small infolding known as sulcus.
 In healthy person upto free gingival margin.
 The sulcular epithelium is non keratinized.

67.  It lacks epithelial ridges at interface.
 Epithelium is thinner as compare to gingiva.
 When sulcus is deep it is known as Pocket.
 Another view holds that initialy gingiva attaches to
whole of the teeth and sulcus formed as a result of
pathologic disease.

68. Dentogingival junction
 Junction of tooth and gingiva.
 Bears mechanical forces and resistant to bacterial
infection.
 Epithelial injury is repaired by migration and
connective tissue can be repaired by formation of
collagen.
 Defence against the bacterial injury is the function of
the cells present on the epithelium such as
macrophages lymphocyte plasma cell PMNL.

69.  langerhance cell produced antibodies against the
bacterial invasion.
 Keratinocytes produced the interferon to kill these
bacteria.
 Lysosomes at the junctional epithelium also kill the
bacteria by engulfment.

70. Development of junctional
epithelium
 Ameloblast form enamel.
 After enamel formation a thin layer of ameloblast is
there it is called enamel cuticle.
 Enamel cuticle attached to the ameloblast.

71.  Now ameloblast lost its fuction and cellular structure it
becomes cuboidal.
 This layer of ameloblast surround the tooth upto CEJ.
 When the tooth erupts the two layer of enmel cuticle
and the OMM comes in contact and fuse with each
other.
 The remanent of primary cuticle afer eruption is
known as NASMYTH’S MEMBRANE.

72.  As the tooth erupts the reduced enamel epithelium
surrounds the crown of the tooth get short and forms
gingival sulcus.
 It is bounded by the attachment epithelium at its base
and the gingival margin lateraly.
 The part of gingiva form sulcus is free gingiva or
marginal.

73. Shift of Dentogingival Junction
 When the tooth erupts the epithelium covers almost
all the surface of tooth.
 It removes gradualy when the crown erupts and
reaches occlusal level.
 The actual movement of the teeth towrds the occlusal
surface is known as active eruption.
 The seperation of epithelium to the enamel surface is
known as passive eruption.
 When cementum exposed it is known as recession.

74.  When reduced enamel epithelium disappeared the
primary attachment epithelium is replaced by a
secondary attachment epithelium derived from
gingival epithelium.

75.  First stage-sulcus bottom resides in the enamel and
the apical end of the attachment stays at the CEJ.
 Second stage-bottom at the enamel and apical end at
the cementum.
 This apical shift is by dissolution of fiber bundle by
enzymes formed by the epithelial cells by plaque
metabolites, by periodontitis.
 May be 40 years or later

76.  Third stage-the bottom of the sulcus at the CEJ and
the epithelium at the cementum.
 Its not a passive eruption.
 Fourth stage- recession of the gingiva.
 May occur wihout PDL disease.

77.  Different location have different stages.
 Anatomic crown and clinical crown.
 In the first and second stage the clinical crown is
smaller than the anatomic crown.
 In third stage both are equal at initial stage but the size
of clinical crown is larger than anatomic crown.

78. Deepening of sulcus (pocket
formation)
 Normal is below 0.5 mm.
 Average is 1.8mm.
 Lymphocytes and plasma cell along with the
langerhance giant cells.

79. Thank you