ORAL MUCOUS MEMBRANE........

1. ORAL MUCOUS
MEMBRANE
By_Arindam Mondal.By_Arindam Mondal.

2. Introduction :
Mucous membrane is a moist lining.
The moist lining of the oral cavity called oral mucous membrane
or oral mucosa. It is in continuation with skin on one end and
the esophagus on the other.
oral mucosa shows modifications according to stress, strain,and
workload.
Oral cavity :
1.Outer vestibule –bounded by lips, cheeks, alveolar bone and
teeth.
2.Oral cavity proper – seperated from the outer vestibule by the
alveolus bearing the teeth.

3. Boundaries of oral cavity
a)Superior border: formed by hard and soft palate.
b)Inferior border: floor of mouth and base of
tongue.
c)Posterior border: pillars of fauces and tonsils
d)Anterior and anterio-lateral borders: lips and
cheeks
The epithelium of the oral mucosa originates partly
from the ECTODERM (lips, vestibule, gingiva,
cheeks, palate, floor of the mouth), and partly
from the endoderm (tongue).

4. Functions
• Protection/ Defense
– acts as major barrier for the entry of
microorganisms.
--It is impermeable to bacterial toxins
-- secretes antibodies & has an efficient
humoral & cell mediated immunity.
--Protects from mechanical trauma
during mastication
• Sensation – receptors that respond to
temperature, touch, pain, taste;
-- initiates reflexes such as swallowing,
gagging and salivation

5. •Secretion / lubrication– saliva,
contributes to the maintenance of
moist surface thus prevents from drying
&cracking
--thus helps in mastication , speech ,
swallowing
•Permeability and Absorption – thinnest
epithelial regions, floor of the mouth,
more permeable than other areas
•Thermal Regulation – dogs, body heat
is dissipated thru the oral mucosa by
panting

6. Classification
Depending on functional adaptation – 3 types
1.MASTICATORY MUCOSA – gingiva and hard palate
comes in primary contact with food during mastication
and is keratinized.
Bound to bone and non -stretchable
1.LINING MUCOSA – the lips cheeks, vestibule, floor of the
mouth, interior surface of the tongue and soft palate.
It does not function in mastication .
It is soft, pliable and non-keratinized.
1.SPECIALIZED MUCOSA – on the dorsal surface (dorsum) of
the tongue. It is covered with cornified epithelial papillae.
Depending on keratinization
1.Keratinized – (masticatory mucosa) hard palate
and gingiva, vermilion border of lip
2.Non keratinized – lips, cheeks, alveolar mucosa,
floor of mouth

7. General Histologic Characteristics of
Oral Mucosa
Two main tissue components:
•Oral epithelium – stratified squamous
epithelium
•Lamina Propia or Corium – underlying
connective tissue layer
The oral mucosa is attached to the
underlying structures by a layer of
loose fatty or granular connective
tissue containing major blood vessels
and nerves
OM resembles Skin in many ways.

8. The two tissues are intimately connected at their junctions
,BASEMENT MEMBRANE OR BASAL LAMINA.
Basement Membrane – interface between epithelium and CT,
evident under LM
It is structureless layer about 1 – 2 micrometers thick
Basal Lamina -- interface between epithelium and CT, evident
under EM
RETE RIDGES
BM

9. The junction between oral epithelium and CT is a corrugated
surface.
The papillae of CT protrude towards epithelium and have BV and
nerves.
The epithelium in turn is formed into ridges that protrude towards
the CT called epithelial rete ridges.
The importance of this corrugated arrangement makes the
surface area of interface larger, better attachment, forces
disperse over greater area of CT.
The junction is a major route for metabolic exchange.
Epithelium has no blood vessels.

10. Basement membrane (BM)
• Interface b/w epithelium & CT in LM.
• Appears thick and include reticular fibres
• 1-4 µm wide and cell free
• PAS +ve
Ultrastructurally, BM is called basal lamina; it is a
basal complex consisting of lamina and fibres.
Basal lamina :
a) clear zone (lamina lucida) – below epithelial cells
20 -40 nm wide glycoprotein layer ; contains type IV
collagen and laminin
a) dark zone (lamina densa) – beyond lamina
lucida Contains type IV collagen coated with
heparan sulfate in net like (chicken wire )
configuration.
BM -promote differentition ,
- promote peripheral nerve regeneration and
growth
- tend to prevent metastasis.

11. Connective tissue
Connective tissue can be differentiated as
Lamina Propria and Submucosa
• Papillary layer or Connective tissue papilla
• Indents and interdigitates with the epithelium (rete
ridges/pegs)
• May be short or absent in some mucosa
• Reticular Layer
• Consists of densely arranged connective tissue
fibers (reticular).This zone is always present.
• Lamina propria consists of blood vessels and
cells like fibroblasts, cells of blood vessels and
lymphatics and nerves. Mast cells and
macrophages are also present.
• Epithelium is avascular, hence its metabolic
needs come via the vessels of the lamina
propria

12. Oral Mucous Membrane

13. • Ground substance of lamina propria
contains glycoprotein and proteoglycan
(hyaluronan, heparan sulfate, versican,
decorin biglycan and syndecan).
• The collagen fibers present in LP are type I
and III
• LP attach to periosteum or overlay sub
mucosa, which varies in different regions of
the mouth

14. • Submucos
• Submucosaliesbelow thelaminapropria and serves
as an attachment between lamina propria and bone
or skeletal muscle
• This attachment is loose or firm depend on
character of submucosa.
• It isfound in thecheeks, lipsand partsof thepalate
• It consists of large blood vessels, nerves and
lymphatics and its functions are nutrition and
defense

15. STRUCTURE / HISTOLOGY OF
Keratinized Oral Epithelium
--It is st. sqamous epithelium
Consist of 4 layers
1.Stratum Basale
2.Stratum Spinosum
3.Stratum Granulosum
4.Stratum Corneum
A single cell (keratinocyte) is, at different
times, a part of each layer.
•After mitosis ------ differention --- maturation

16. Basal cell layer : stratum basale , stratum
germinativum
- It is a single cell layer resting on basal lamina
which are cuboidal or low columnar
- these cells undergo division to make up for the
cells shed off from the surface.
- attached by hemidesmosomes & desmosomes &
provide mechanical linkage amongst oral
epithelial cell
- stratum germinativum- basal & parabasal spinous
cells are referred to as the st. germinativum.
- Synthesize proteins (ribosomes ,RER) , & forms
intermediate filament of basal cells ,
basal layer made up of 2types –
- 1)serrated & heavily packed with
tonofilaments ,which are adaptation for
attachment
- 2)non serrated composed of stem cells .

17. Stratum spinosum / Spinous cell layer
• several rows of larger elliptical or spherical cells/ polyhedral cells ,
& Larger than basal cells
• appearance of cells when prepared for histologic examination –
shrink away from each other remaining in contact only at point
known as intercellular bridges or desmosomes, hence called
Prickle cell layer, resemble cocklebur or sticker
• Synthesize more active proteins that differs from basal cell
• The desmosomes & attachment plaque contain the
polypeptides desmoplakin and plakoglobin and these are used
as marker for detection of carcinomas.
• The tonofilament and desmosomes makes a tensile strength for
the epithelium .

18. Stratum Granulosum /Granular cell layer:
• Cells are 5-6 cells thick, are flatter and wider
• Larger than spinous cell layer
• Prominent in KE and absent in Non-KE
• These cells have basophilic keratohyaline
granule
• Nuclei show sign of degeneration and pyknosis.
• Synthesize proteins but differs in rate &
diminishes as it reaches the st. corneum ,Cells
become very dense
• Expression of additional marker as fillagrin and
trichohyalin
• A lamellar granule, a small organelle forms in
upper spinous & Granular cell layer also k/as
Keratinosome, Odland body or membrane
coating granule.(Glycolipids). This forms a barrier
at the junction of st. corneum & granular layer.

19. Stratum corneum / Keratin layer:
• dehydrated and flattened thus more resistant to mechanical
damage and chemical solvents
• assume the form of hexagonal disks called squames
• do not contain any nuclei ,& organelles
• This layer is acidophilic in H&E and amorphous.
• Composed of densely packed filaments , altered and coated by
fillagrin
• up to 20 layers of squames and is thicker than that of most of the
skin except the soles and palms
Keratin layer may be orthokeratinized or parakeratinized.

20. Keratinization(types)
• Orthokeratinization - About 20-30% of the
gingiva, the stratum corneum is
homogenous and made up of flat, closely
packed keratinized cells without nuclei
• Parakeratinization - Approximately 50-70%
of the cases, the stratum corneum is
homogeneous and consists of flat
keratinized cells with pyknotic nuclei and
remnants of cytoplasmic organelles
• Non keratinized-

21. KERATINIZATION:
• Keratinocyte is an epithelial cell that
ultimately keratinize
• It involves series of biochemical and
morphological events
These changes occur starting from basal cell
layer to the corneal layer
Hence process of keratinization can be
explained on following 4 steps and are
• Gradual flattening of cell
• Disappearance of nucleus
• Increased prevalence of Tonofilaments
• Increased prevalence of Keratohyaline
granules
TONOFILAMENTS ARE NOTHING BUT PROTEIN

22. • In both types of epithelia the cells increase in size (more
in Non-KE) and migrate from basal cell layer to the
prickle cell layer.
• In the prickle cell layer there is an active synthesis of
tonofilaments, which in KE aggregate together to form
tonofibrils.
• In the next layer (granular Layer/intermediate layer) the
cells are greater in volume but more flattened.
• They contain the so called membrane coating
granules.
• In the upper part of this layer the granules fuse with the
cell membrane to discharge their content into the
intercellular space

23. • In KE the content is lipid rich and form a barrier to limit the
movement of aqueous substances.
• In Non-KE the contents have a different lipid composition .
• The cells of the superficial part of the gr. Layer develop a
thickening of their cell membrane to form a barrier against
chemical solvents
• The most characteristic feature of the granular layer is the
keratohyaline granules.
• It is thought that keratohyaline granules facilitate the
aggregation of the tonofilaments

24. Maturation in oral epithelium
• As the cells of the gr. Layer reach the junction with the
keratinized layer, a sudden change occurs:
•All organelles, including the nuclei and keratohyaline
granules disappear, The cells dehydrate,
•The cells become packed very densely and the cells
become more flattened .
• The form of the cells become hexagonal, the so called
squames.
• The squames will be in the process of desquamation
lost.

25. Keratin squames
KERATINIZED AND PARAKERATINIZED
---KERATOSIS AND PARAKERATOSIS

26. NON- KERATINIZED EPITHELIUM
• Stratum Basale /Basal cell layer
• Cuboidal or columnar cells containing separate
tonofilaments and other cell organelles
• Site of most cell divisions
• Stratum Intermedium/ intermediate layer
• Slightly increase in cell size as well as accumulation
of glycogen in cells of the surface layer
--On rare occasion, keratohyalin granules can be
see
• Stratum Superficiale ( Superficial layer)
• Cells appear slightly flattened than in the
preceding layers and contain dispersed
tonofilaments and nuclei, the number of
other cell organelles having diminished
NKE have higher rates of mitoses than KE.

27. NON KERATINOCYTES
-A epithelium contain cells that do not keratinize & do not posses
cytokeratin filaments called NON KERATINOCYTES.
- Do not show mitotic activity, no desquamation
- do not have desmosomal attachment with keratinocyte
- Do not stained in H & E ,and identified by special stain or
immunohistochemical methods.
- 3 groups of cells MERKEL CELL, MELANOCYTES , LANGERHANS
CELL.
- These cells migrate to the oral epithelium from neural crest or
bone marrow.

28. Melanocytes : dendritic cell / Clear cell
• Resides in basal cell layer,
• derived from neural crest
• Each melanocyte establish contact with 30-40 keratinocyte
through their dendritic process.
• Melanin stored in the form of melanosomes . Melanin pigment
dispersed in C.T.phagocytosed by macrophages termed
MELANOPHAGES.
• Melanin pigmentation do not depend on the related number
but activity i.e. no , size and dispersal of melanosomes ,
quantity of melanin in melanosomes and the rate of
degradation of pigment.
• Dopa reaction , Silver staining , Mosan Fontana stain are used
for study

29. Langerhans cell: dendritic cell / Clear cell
• Found in upper layers of epithelium
• Cell has convoluted nucleus and rod like granules in the
cytoplasm ,Birbeck granules
• Hematopoietic origin ,penetrates epithelium from LP
• Free of melanin & no dopa reaction but stain with gold
chloride ,ATPase, immunofluorescent marker.
• Involved in immune response.
• Role in contact hypersensitivity, anti tumor immunity , graft
rejection .

30. Merkel cell:
• Found in basal cells specialized neural pressure –sensitive
receptor cell, migrate from neural crest
• It responds to touch sensation
• Non dendritic cell
• Function not known
• Stained by PAS
Other cells , lymphocytes and PMN are , also seen in
epithelium, which are transient
Keratinocyte and lymphocyte interact and activate lymphocyte
through interleukin 1.
gamma-interferon -----HLA –DR antigen
(keratinocyte)

31. Subdivisions of oral mucosa :
Keratinized areas – Masticatory mucosa
-- vermilion border of lip
vermilion border of lip / vermilion zone
-it is the transitional zone between the skin of the lip and the
mucous membrane of the lip
-it is also called the Red zone, or the vermilion zone.
-it is found only in humans
Histology: skin on the outer surface of lip is ,thick, keratinized
epithelium .
papillae of C.T. are few & short
sweat glands , sebaceous glands associated with hair follicles
occurs.

32. HARD PALATE –
- Mucosa is immovable, fixed to periosteum
- Keratinized epithelium with long papillae
- Lamina propria a layer of dense C.T., thicker in anterior than
posterior
- Depend on submucosal layer various zones of palate can be
distinguished
1)gingival region –adjacent to teeth
2)palatine raphe -incisive to palatine papilla
3)Antero-lateral or fatty zone
4) Posterolateral or glandular zone
The submucosal space is subdivided into
irregular intercommunicating compartments of various sizes

33. Transitional zone is thicker
but mildly keratinized
epithelium ,long papillae
reaching deep into
epithelium carrying large
capillary loops to the
surface
Do not contain glands –
drying & cracking
blood is visible & hence
red lips
Towards lip thickness of
epithelium increases .the
lip is thicker & non –
keratinized

34. Hard Palate and Soft Palate

35. Palatine raphe and palatine tissue peripherally do not have
submucosal layer.
In the other zones of palate the submucosa shows dense bands
and trabeculae of fibrous connective tissue.
In the anterior part filled with adipose tissue and glands in the
posterior part.
The presence of fat or glands in the submucosal layer act as a
cushion .
in the lateral part, in both zones the lamina propria is fixed to the
periosteum by bands of dense fibrous C.T.
These bands are arranged at right angles to the surface and
divide submucosal layer into irregular spaces

36. INCISIVE PAPILLA
• Formed of dense CT
• Contains oral parts of vestigial nasopalatine ducts which are
blind ducts of varying length lined by simple or pseudostratified
columnar epithelium, rich in goblet cells.
• The nasopalatine ducts are patent and together with
Jacobson’s organ are considered auxillary olfactory sense
organ.
• Jacobson’s organ is a small cigar- shaped structure lined with
olfactory epithelium apparent in 12th
- 15th
fetal week and later
undergoes involution

37. PALATINE RUGAE(transverse palatine ridges)
• Irregular & often asymmetric
• The ridges are of MM extending laterally from incisive papilla
and anterior part of the raphe
• Their core is made up of dense CT
EPITHELIAL PEARLS
• In the region of incisive papilla this can be seen in LP, which
consists of concentrically arranged epithelial cells, frequently
keratinized.
• The are remnants of the epithelium formed in the fusion
between palatine process.

38. A - stratum corneum
B - capillary
C - connective tissue
papilla
D - rete peg
E - lamina propria

39. GINGIVA
• Extend from dentogingival junction to the alveolar mucosa.
• Is normally pale pink but sometimes with greyish tint
Color depends on keratinization, thickness, melanin
pigmentation.
• Surface may be translucent or transparent permitting the color
of underlying tissue
• It is limited on the outer surface of both jaws by the
mucogingival junction(MJ) separates from alveolar mucosa
• Alveolar mucosa red and vessels course through it.
• MJ is identified as junction between bright pink alveolar
mucosa and pale pink gingiva.
• Lingually it demarcates from the mucosa of floor of mouth.
However, palatally the distinction is not so sharp

40. GINGIVA OR MARGINAL
EPITHELIUM

41. GINGIVA :can be divided into 3 parts
- Free gingiva
- Interdental papilla
- Attached gingiva
• Free gingiva mucogingival junct
• a narrow band of tissue that follows the scalloped contour the
necks of the teeth and the cementoenamel junction
• is referred to as “free” because it can be moved mechanically
along tooth surface as well as away from the tooth

42. Anatomy of gingiva

43. Free Gingival groove (FGG)-
It is a line between free gingiva and gingiva,
Runs parallel to the margin of the gingiva at a distance of .5 to
1.5mm
FGG not always visible microscopically but appears as a V
shape notch
It develops at the level of, or somewhat apical to, the bottom of
the gingiva sulcus
Attached gingiva:
-about 4-6mm
-stippling is present (elevation &
depresion of epithelium)
Functional adaptation to mechanical impacts
Stippling vary with age, sex & in different individual.
The gingiva appears slightly depressed in between adjacent
teeth corresponding to the eminences of sockets on alveolar
process

44. Interdental papilla:
• Part of gingiva fills the space between 2 adjacent teeth.
• It is triangular in shape
• In 3D view ,papilla appears tent shaped in post teeth, while
pyramidal in anterior teeth.
COL – the constriction (concavity ) in between the facial and lingual
interdental gingival papilla & below contact point called col.
• Non keratinized epoithelium
• Vulnerable for periodontal disease
GINGIVAL SULCUS – a shallow groove extending around the
circumference of the tooth
• Depth varies from 0.6 mm and has the average depth of 1.8 mm

45. GINGIVAL SULCUS
FREE GINGIVA
GINGIVAL GROOVE
ATTACHED GINGIVA
ALVEOLAR MUCOSA

46. Histology:
- The epithelium is keratinized,
parakeratinized(75%), orthokeratinized (15%), non
keratinized(10%)
- C.T consist of dense fibrous tissue does not
contain large vessels
- The papillae of C.T are long slender & numerous .
- LP contains few elastic fibers, mostly confined to
the walls of BV. Oxytalan fibers are also present
- Few lymphocyte, plasma & macrophages are
present.
- Gingival fibers of PDL enters LP, giving firm
attachment to tooth.
- Fiber in LP of alveolar mucosa is loosely textured

47. Collagen fibers in LP of gingiva arranged in
groups , referred as Gingival Ligament
divided into following groups:
1-Dentogingival -Most numerous.
extend from cervical cementum into LP of
gingiva.
2-Alveologingival- arise from alveolar crest &
extend into LP
3-Circular –fibers that circle the tooth
4 –Dentoperiosteal- followed from cementum
to alveolar bone
5 – transseptal – accessory fibers extend
interproximally between adjacent teeth .
These fibers also called INTERDENTAL
LIGAMENT.
Apart from these fibres interdental, semicircular
trans – gingival vertical fibres are also present.

48. Alveolar Mucosa

49. NON –KERATINIZED AREAS/LINING MUCOSA
LIP AND CHEEK MUCOSA:
• Epithelium is non-keratinized st. sq. epithelium.
• LP of labial & buccal mucosa is consist of
dense C.T. with short and irregular papillae.
• Submucosal layer connects LP to the fascia of
muscles, & strands of densely group of fibers
• Between these strands there is a loose C.T.
containing fat and mixed S.G.
• The strands of dense CT limit the mobility of
MM holding it to musculature and preventing
its elevation into folds and hence prevent
from biting.
• the submucosa may contain isolated
sebaceous gland called Fordyce spots.

50. VESTIBULAR FORNIX AND ALVEOLAR MUCOSA
• The gingival mucosa joins the alveolar mucosa at the
mucogingival junction.
• It is present only in the vestibular region and extends from the
scalloped mucogingival junction to the vestibular fornix, where
it is continuous with the mucosa covering the lips and cheeks.
• It is movable, can be lifted to a limited extent from its base.
• It exhibits structural deep red in color.
• It has a smooth surface.
• The median and lateral labial frenula are folds of the MM
containing loose CT .no muscle fobres are found in these folds.

51. ALVEOLAR MUCOSA (histology)
• The alveolar mucosa is thin well
defined submucosal layer of
loose CT
• The epithelium is thin and non
keratinized
• Epithelial ridges and papillae
are low and often missing

52. FLOOR OF THE MOUTH
• The mucous membrane of the floor
of the mouth is thin and loosely
attached to the underlying
structures to allow free mobility of
tongue
• Epithelium is non keratinized
• Papillae of LP are short
• Submucosa contains adipose tissue
• The sublingual mucosa reflects onto
lower surface of tongue and
continues as ventro-lingual mucosa

53. Ventral surface of the
tongue
• MM is relatively thin
and smooth
• Epithelium is non
keratinized
• papillae of CT are
numerous but short
• The lining mucosa
here contains both
lamina propria and
submucosa
• The submucosa
merges with the
muscle bundles of the
ventral surface of the

54. SOFT PALATE
• MM is highly vascularized
• More pink than the mucosa of the keratinized hard palate
HISTOLOGY
• Epithelium is non-keratinizing stratified squamous epithelium
• Papillae of CT are few and short
• lamina propia contains many small blood vessels and elastic
fibres
• submucosa contains muscles and mucous gland. It also
contains taste buds

55. SPECIALIZED MUCOSA:
• Specialized mucosa covers the dots and surface of the tong .
• Surface is rough and irregular,
• It has 2 parts – divided by V shaped sulcus
anterior part – 2/3rd , Body ,
_ posterior base-, 1/3rd
, base
• Develop embryologically from
different visceral arches ,hence
different nerve supply
• Ant 2/3rd
–lingual nerve(trigeminal) and
• Post 1/3rd –
chorda tympani nerve
(glassopharyngeal)

56. • The body and base differs in the structure of MM.
• Anterior part covered with papillae , termed ‘papillary’and
Posterior part the “lymphatic “
• Surface covered by modified , keratinized , stratified epithelium
• Anterior or papillary part covered with numerous fine –pointed,
cone shaped papillaethat gives velvet appearance.
_Filiform papillae
-- Fungiform papillae
--Circumvallate papille
---Foliate papillae

57. FILIFORM PAPILLAE :
Filliform papillae are the most
numerous.
Appear as short rough , thread
shaped structures covered with
thick keratinized epithelium,
containing a core of CT
They do not contain taste buds.

58. • Fungiform Papillae:
• The fungiform papillae are interspersed
between filiform papillae across the
surface of tongue.
• They are more box-like, (mushroom shped)
with a connective tissue corewith rich
capillary network and overlying thin
covering of epithelium
• Apears round reddish prominences
• Most of the fungiform papillae contain a
single taste bud on the tip.

59. • Circumvallate Papillae:
• The larger circumvallate papillae are
located infront of v-shaped terminal sulcus
on the dorsal surface, appearing as pin-
cushions with a surrounding trough, called
crypt. Von –ebners glands open into this
trough.
• The pores of taste bud open into the crypt.
• In humans there are 12-15
• Crypt is lined by an epithelium , called
gustatory epithelium , which contains
several taste buds.

60. • Foliate Papillae:
• Foliate papillae lie on the
lateral sides of the tongue and
appear like slits.
• These are less developed in
rats and humans than they are
in other species.

61. • TASTE BUDS:
•Taste buds are the anatomical structures which contain the
receptor cells that mediates the sense of taste.
•Taste buds are found in the oral cavity , primarily on the
tongue but also on the palate , pharynx , epiglottis and
larynx.
• Each taste bud is small ovoid or barrel shaped organ ,80 µm
high and 40 µm .

62. • Each taste bud opens to the epithelial surface via a small
opening called a taste pore.
• From this pore protrudes the microvilli arising from the tips of
the individual taste cells.
• Taste pore leads into narrow space lined by supporting cells
• Each taste bud contains 50–100 taste receptor cells
(neuroepithelial cells) and supporting cells.
• Taste cells are described as basal, dark, intermediate, and light,
based on electron microscopic characteristics .

64. • The basal cells are at the base of the taste bud and constitute a proliferative
population of cells.
• They divide to produce postmitotic light, intermedi cells ate, and dark taste cells
with a life span of 10–11 days.
• Dark cells are slender defined by a dark cytoplasm (electron-dense), dense-core
granules carry finger like processes at their superficial end. at the tip of the cell,
• Finger like processes appear like hairs in LM.
• Light cells are characterized by a light cytoplasm (electron-lucent), clear vesicles
and mitochondria in the tip of the cell, and a round to oval nucleus .
• Intermediate cells have characteristics that are intermediate between the light
and dark cells .

65. •Taste cells have also been designated as Type I, II, III, and IV,
•with Type I being similar to dark cells,
•Type II similar to light cells,
•Type III similar to intermediate cells
and
•Type IV being the basal cells..
•Rich plexus of nerve is found below the tastebud
•Taste sensation –sweet –tip of tongue==fungiform at tip
• salty- lateral border== fungiform atlateral
• bitter – posterior, middle part==vallate papille

66. TASTE LOSS IN HUMANS
Sinificance:
• Ageusia (taste loss)
• Hypogeusia (decrease in taste) and
• Dysgeusia (abnormal taste)
are widespread and associated with a variety of illnesses,
from common to obscure
• Radiation .
• Physiological in pregnancy and menopuse , aging
• Sjogren’ssyndrome, zn deficiency

67. Gingival sulcus :
• The gingival sulcus is the natural
space found between the tooth
and the gum tissue that surrounds
the tooth, known as the free
gingiva
• Healthy gums generally have a
sulcus depth that may range
anywhere from 1 to 3mm.
• Sulcus depths greater than 3mm
occur in patients that have varying
degrees of periodontal disease. This
is referred to as a periodontal
pocket.
• The deapth is at the approximate
level of FGG
• Sulcus may be responsible for FGG.

68. • The sulcular epithelium, which extends from the coronal margin
of the junctional epithelium to the coronal margin of the
marginal gingiva, is a non-keratinized stratified squamous
epithelium.
• This epithelium is thin and semi permeable, which may be
important in the pathogenesis of periodontal disease as injurious
bacterial products may pass into the gingiva and tissue fluids
and humoral defense components may pass into the sulcus.
• Sulcular epithelium is continuous with attachment epithelium
,with coextensive basal lamina

69. GINGIVAL CREVICULAR FLUID:GCF
• The sulcus contains fluid(GCF) that
passes through the JE
• The purpose of the fluid
• Defense mechanism of the DGJ
• Washes the crevice, carrying out shed
epithelial cells, leucocytes, bacteria and
other debris
• Plasma proteins may influence epithelial
attachment to the tooth
• Contains antimicrobial agents
(lysozymes)
• Carries PMN’s, leucocytes,
macropahges, immunoglobulins

70. DENTOGINGIVAL JUNCTION:
• It is the junction between gingiva and tooth
• Defined as the oral epithelium that extends from the
mucogingival junction to the gingival margin where
crevicular/sulcular epithelium lines the sulcus
• At the base of the sulcus  connection between gingiva and
tooth is mediated with JUNCTIONAL EPITHELIUM /AATACHMENT
EPITHELIUM
• The union between this epithelium and tooth is referred to as
EPITHELIAL ATTACHMENT

71. Junctional epithelium :JE
• It is non differentiating , non keratinizing tissue and different
from gingival epithelium
• JE extends up to 2mm on the surface of the tooth.
• Highest turnover-5-6 days , Epithelial cells migrate coronally &
shed into oral cavity via gingival crevice
• Rate of turnover dependent on demands placed on tissue.
Directly related to degree of inflammation
• Highly permeable with large intercellular spaces and also
permits easy flow of GCF.
• The attachment of JE to the tooth by epithelium contributes to
the integrity of DGJ in health .
• Firmness is maintained by gingival fibres ofPDL.

72. apically - 1 to 3 cells thick
Coronally - 15 to 30 cells thick
Total thickness - 30 to 100/um Length -
0.25 to 1.35 mm
Apical zone: - Contains fewer
hemidesmosomes and cell with
germinative characteristics.
Middle zone:- area of greatest
attachment having large numbers of
hemidesmosomes
Coronal zone:- area of greatest
permeability characterized by numerous
intercellular spaces. Some of which
directly open into internal basal lamina

73. • Cells of JE immediately adjacent to tooth attach to tooth by
hemidesmosomes & basal lamina
• Combination is known as the epithelial attachment
• Basal lamina in contact with tooth: Internal Basal lamina
• On opposite surface – JE in contact with lamina propria of
gingiva & attached by hemidesmosomes and basal lamina
• Basal lamina in contact with lamina propria: External Basal
Lamina

74. JUNCTIONAL EPITHELIUM IS UNIQUE AS IT
POSSESS 2 BASEMENT MEMBRANES – THE
INTERNAL AND EXTERNAL BASAL LAMINA
• Histology:
Ename
l
Lamina
propria
Internal Basal Lamina External Basal
Lamina
Hemidesmosomes

75. Role of JE- Clinical significance:
• The union is unique in many ways & a point of lessened
resistance to mechanical forces and bacterial attack.
• GCF contains globulins and (PMNs) giving it
immunological / phagocytic properties to combat disease
processes(lymphocytes and plasma cells ),langerhans cells.
• Such molecules pass readily across JE to underlying tissues
• JE (& GCF) good indicator for severity of periodontal
disease – may contain neutrophils & other inflammatory
cells indicating disease & state of health of periodontium

76. Development of DGJ and shift of DGJ:
• Shortly after the onset of amelogenesis, the stellate
reticulum (SR) shrinks considerably so that the outer
enamel epithelium (OEE) comes into close contact
with the stratum intermedium cells.
• The collapse of the enamel organ results in the
formation of the reduced enamel epithelium &
covers entire surface upto CEJ
• The external cells of the reduced enamel
epithelium consist of undifferentiated epithelial cells
able to divide and multiply epithelium that will
eventually give rise to the junctional epithelium.

77. • REE replaced once tooth erupts – REE covering
crown lost rapidly replaced by squamous
epithelial cells
• Transformed REE & oral epithelium form
Dentogingival junction and junctional epithelium
• Final conversion of REE to JE may not occur until 3-
4 years post eruption

78. • As the erupting tooth approaches the
overlying epithelium, the external cells
of the reduced enamel epithelium
proliferate, causing the epithelial
covering of the enamel to thicken.
• Proliferation of the external cells of the
reduced enamel epithelium begins
around the cusp tips and slowly
progresses toward the cervix of the
tooth
• REE & OE meet & fuse . The remnants of
Iry enamel cuticle after eruption
reffered as Nasmyth’s membrane.

79. • As tooth eruption starts , the outer layer of the
reduced enamel layer of oral epithelium will
proliferate into the degenerated C.T. to form
a mass of cells over the erupting tooth
(epithelial plug). REE
• At the time of active eruption the REE covers
entire enamel surface
• Cell death in the middle of the epithelial plug
leads to the formation of epithelial lined canal
through which tooth will erupt. FREE GINGIV

80. • Once the tip of the crown appears in the oral
cavity enamel epithelium will be called primary
attachment epithelium.
• At the margin of gingiva the primary
attachment epithelium is continuous with oral
epithelium
• After tip emerges into oral cavity the
epithelium separates rapidly away from tooth
& when it comes into occlusion it slows down.
• Actual movement of teeth towards occlusion
termed active eruption

81. • Separation of IRY attachment
epithelium from enamel is passive
eruption.
• The shallow groove present between
the tooth and the gingiva is called
gingival sulcus.
• It deepens as a result separation of
REE
• Gradually REE is lost and cells of oral
epithelium contact to the tooth
surface
• The replacement of IRY attachment
epithelium with cells of gingival
epithelium called IInd ry attachment
epithelium .
• The epithelial cells arereferred to as
junctional epithelium and zone of
attachment is epithelial attachment.

82. • Crown exposure during Passive
eruption and further recession has
been classified into 4 stages by
Gottlieb and orban (1933):
• The 1st
two may be physiologic and
pathologic
• Stage 1: The junctional epithelium is
located entirely over the enamel. This
relation persist in Iry almost upto 1yrof
age before shedding and permanent
upto 20-30yrs

83. • Stage 2: The junctional epithelium is
located in part over the enamel and in
part over the cementum.
• This is due to dissolution of gingival and
transseptal fibres
• This is due to distruction formed by
plaque metabolites or enzymes .
• This stage of tooth exposure may persist
to the age of 40 yrs or later

84. • Stage 3: The entire junctional epithelium is
located over cementum, with its coronal end
at the cemento-enamel junction.
• Enamel covered crown is fully exposed
• This stage is no longer a passive eruption .

85. • Stage 4: The entire junctional epithelium is located apical to the
cemento-enamel junction
• Represent recession of gingiva. Gingiva appears normal
• It may occur without clinical
evidence of inflammatory
condition

86. • The rate of crown exposure &recession varies with individual
• 1st
stage may be seen in 20 yrs &also 50 yrs
• Rate also varies in different teeth of same jaw different surfaces
in same tooth.
• Gradual exposure makes it to distinguish between clinical and
Anatomical crown
• 1st
&2nd
stage ---clinical crown< anatomical crown
• 3rd
stage--- clinical crown = anatomical crown
• 4th
stage--- clinical crown > anatomical crown.

87. Age changes in Oral mucosa
• OM may become dry & smooth due to
in salivary secretion & epithelial ridges
• Smooth tongue due to decreased fungiform papillae
and nutritional deficiency.
• Lingual varices –varicose lingual veins
• Decline cell mediated immunity due fewer Langerhans cells with
age
• Nerve endings may affect which may lead to progressive loss of
thermal sensitivity ,chemical & mechanical stimuli
• Decrease in taste perception .

88. CLINICAL CONSIDERATION ;
• PERIODONTAL POCKET—Plaque toxins &
immunologic response . T/t given to pocket
depth.
• INJURY TO JE --- during brushing, flossing & probing
JE is delicate site for such insults and hallmark of
periodontitis
Level of gingival attachment is imp in restorative
dentistry as clinical crown smaller. In stage 1 , the
restoration should placed at level of gingival
sulcus
Avoid injury to gingiva, DGJ , & prevent premature
recession
If periodontal disease is there, 1st
carry t/t for that &
then do restoration

89. • Gingival recession –Cemental caries and Abrasion
may occur ----sensitive to thermal and chemical
stimuli
desensitizing drugs to accelerate sclerosis and
formation of reparative dentin
• Structure of mucosa is important , masticatory
mucosa causes no gap in healing due its firmness ,
however lining mucosa needs suturing as it is
loosely bound to underlying structure
Infiltration of LA is difficult in masticatory than
lining mucosa
• Difference in permeability may be related to
prevalence of certain mucosal diseases and
utilized for drug delivery
• Healing is faster than skin due to profused supply
and no scarring , due to collagen

90. • Bacteria colonized on surface of epithelium .and
shed along with the cell. The desquamated cells
are present in the saliva usually settle on the rough
surface of the dorsum of tongue forming a white
coating. The thickness of the coating increases in
states, where mouth becomes dry like in fever.
• The gingiva is exposed to heavy mechanical stress
during mastication.
Keratinization of the gingiva may afford relative
protection. Eg. By brushing or massaging
• Many systemic disease causes characteristic
changes in oral mucosa .e.g. metal poisoning.,
leukemia anemia, other Bl diseases, measles,
hormonal imbalance .

91. • Changes on tongue are diagnostically significant
Scarlet fever-atrophy of lingual mucosa causes peculiar
redness .
Pernicious anemia deficiency , ,B-complex deficiency, lead to
characteristic changes as magenta tongue and beefy red
tongue
• Fordyce’s spot
• Mutation of genes affects the skin and mucosa e.g.
vesiculobullous lesion , epidermolysis bullosa

92. •THANK UTHANK U