classification of oral mucosa and junctions

1. Oral Mucosa
DR. Mahitabe Elgamily
Part 2

2. Objectives
1. Types of oral mucosa
a) Masticatory.
b) Lining .
c) Specialized. (taste buds, taste perception)
2. Junctions in oral mucosa
a) Mucogingival
b) Mucocutaneous
c) Dentogingival
3. Clinical consideration & age changes.

3. Masticatory
mucosa

4. Gingiva
 Covers the teeth neck and part of the alveolar
bone.
 Pale pink in color.
 Pigmented in colored races.
 Separated from the alveolar mucosa by a
scalloped line called mucogingival junction
(healthy line)
 The mucogingival junction not present on the
palatal aspect of the upper jaw.
 on lingual surface of lower jaw the gingiva is
directly attached to mucosa of floor of mouth

5. Gingiva
Free gingiva Attached gingiva
Interdental
gingiva
 Keratinized except sulcus & col
 No sub mucosa
 directly attached to cervical cementum or
periostium of bone

6. 1-Free gingiva
 It extends along the cervical level of the tooth at the labial,
buccal and lingual surface.
 It is freely movable and extends to the bottom of the gingival
sulcus or slightly below (1-1.5 mm)
 It is taper to knife edge (gingival margin)
 free gingival groove:
 Separates the free gingiva from attached gingiva.
 appears as shallow V shaped notch corresponding to heavy
epithelial rete pegs found between free and attached gingiva.
 Formed due to functional impact on free gingiva

8. Gingival sulcus
 Def:
It is the space between the gingiva and the tooth
surface
 Histology :
• lined by non-keratinized epithelium
• Lack epi rete pigs in normal conditions.
• Lymphocytes and plasma cells commonly seen in the CT for defense
dto constant presence of bacteria so act as a barrier to prevent bact
penetration or its toxins
 Depth:
• varies from 0 to 6 mm with average 1.8 mm.
• The more shallow the sulcus the more favorable the condition of
the gingival margin.

9. 2-Attached gingiva
 It is immovable and attached to cementum and periosteum.
 It extended from the free gingival groove to the mucogingival junction (which
separate the attached gingiva from the alveolar mucosa)
 The attached gingival depressed between the eminences of the sockets forming
grooves called inter- dental grooves.

10.  Its surface shows stippling which is due to functional adaptation to
mechanical stresses.
 The elevation of stippling correspond to high C.T papillae and the
depression to the heavier epithelial rete pegs.
 Absence of stippling denotes inflammation.

11. 3-Inter dental papilla
Place:
-fills the inter-proximal spaces between the adjacent teeth
bellow the contact area.
- In posterior teeth the apex depressed under the C.A
resulting in two peaks( B&L), the depression between the
two peaks of inter dental papilla called inter dental col.
-The col is covered by non-keratinized epithelium.
 shape:
-Pyramidal shape anteriorly.
-Tent shape posteriorly.

12. Boundaries:
• base extends from the center of one tooth to the
center of the adjacent.
• the apex tapers to the contact area.
 Content
• Deep to the inter-dental papilla there are
-gingival& trans septal fiber of the PDL
-the crest of alveolar bone.
 Absence of contact between teeth
The papilla is reduced

13. II. Hard palate
Covered by Pink, firmly attached keratinized mucosa with
long and broad rete pigs.
1.Palatine rugae:
Transverse folds formed of C.T covered by kertinized
epithelium.
2.Palatine gingiva:
Free gingiva, free gingival groove, attached G., No muco-
gingival line.
3.Median palatine raphe:
• Extend from incisive papilla posteriorly.
• The incisive papilla is pear shaped and is formed of
dense Connective tissue that contains the oral part of
the nasopalatine duct (pseudo stratified columnar epi
with goblet cells).

14. 4.Antero-lateral area (fatty zone)
 This area present between the palatine raphe and
the gingiva anteriorly.
 Its lamina propria is fixed to periosteum by bands
of fibrous C.T dividing sub mucosa into
compartments containing fat cells.
5.Posterio- lateral area (glandular zone):
 Present posterior to the fatty zone, the sub mucosa
contains pure mucous glands which facilitate
swallowing, the fatty and glandular zones act as a
cushion.
Fatty
zone
Glandular
zone

15. Clinically
 The firmness of attachment of the
masticatory mucosa means that it doesn’t
gap after surgical incision and rarely
requires suturing .
 The injection of local anesthesia in the
masticatory mucosa especially the hard
palate is very painful due to the stiffness.

16. Lining mucosa
Firmly attached
Soft
palate
cheeks Lips Inferior surface
of tongue
Loosely attached
Alveolar
mucosa
Vestibular
fornix
Floor of
mouth
 To limit the mobility of the mucosa and formation of folds so
lodging between the occlusal surface of teeth during
mastication(in case of lips)
 Prevent gaging in case of soft palate
 Smooth surface during muscular movement

17. firmly
attached
Inferior surface of the
tongue (ventral)
Soft palate Cheek Lip
Epithelium Thin non
K.ST. Sq. EP
-Thin non K.ST. Sq. EP.
With taste buds.
-Pseudo ST. Sq. EP.
Ciliated with goblet cell
from the nasal Side.
Thick non
K. ST. Sq. EP.
1-Lining
mucosa
2-Transitional
Zone (vermilion
border).
3- skin side
Lamina
propria
-Short numerous C.T
papilla take saw teeth
like.
- short C.T Papilla and B.V.
- Layer of elastic fibers
separate L.P. from sub .m.
- short slender Papilla -
contain collagen, -
capillary loops and few
elastic fiber
Submucosa Thin Submucosa
Has minor salivary
mixed glands.
Submucosa C.T contains
mucous salivary glands
and fat cells.
Dense C.T contains fat cell,
minor S.G and Sebaceous
glands. or Fordyce's
granules.
(yellowish spots at the
corners of the mouth)

18. Buccal mucosa with
sebaceous glands
FORDYCES SPOTS

19. Loosely
attached
Alveolar mucosa Vestibular
fornix
Floor of
the mouth
Epithelium Thin Non Keratinized Non Keratinized. Thin NonKeratinized.
Lamina
propria
Short and even missing C.T
Papilla. Collagen fibers are regularly
interwoven.
Short and few papilla
median and lateral labial
fermium are folds of
mucous membrane
contains C.T without
muscles fibers
Few short C.T papillae.
Submucosa -Contain loose C.T
-thick elastic fibers
-mixed salivary gland.
Loose CT to allow free
mobility
Contain fat cells
sublingual submandibular
salivary glands open in
the sublingual folds.

21. Specialized
mucosa

23. The tongue is divided into 2 parts
Anterior 2/3s
Papillary
Posterior 1/3
lymphatic

24. Papillary part
Anterior 2/3
Have different types of fine-
pointed projections called
tongue papillae.
There are 4 types of papilla:
1. Filiform
2. Fungiform
3. Circumvallate
4. Foliate

26. 1. Filiform papilla
 Shape :
Cone, thread shaped papillae.
 structure:
1- keratinized epithelium
2-core of connective tissue from which
secondary papillae protrude toward
the epithelium.
3- do not contain taste buds.

28. 2. Fungiform papilla (red spot)
 Shape:
Mushroom-like, with broad surface and narrower base.
 Place:
-Found between the filiform papillae.
-More on the tip of the tongue(sweet)
- On the lateral borders(salt)
 Clinically:
reddish prominences. Their color is derived from a
rich capillary network visible through the thin epithelium.
 Histologically:
contain a few (1-2) taste buds found only on their
dorsal surface.
Chorda tempani

30. 3. Circumvallate papilla
 Site: Present in front of sulcus terminals, between the body and the base
of the tongue. 8-10 in number.
 Taste:
• Bitter taste sensation mediated by glossopharengeal N

31. They do not protrude above the surface of the tongue but are
bounded by a deep circular furrow so that their only connection to the
substance of the tongue is at their narrow base.

32.  Have numerous secondary papillae that are covered by a thin, smooth non
keratinized epithelium.
Some times there is a thin layer of keratin.
On the lateral surface the epithelium contains numerous taste buds.
The ducts of small serous glands called Von Ebner's
glands open into the trough.
1- it keeps the furrow clean
2- dissolve the food to help in taste sensation.
3- enzymatic activity of salivary lipase &amylase .
Histology:

33. 4. Foliate papilla
 site:
On the lateral border of the posterior parts
of the tongue.
 shape:
• Sharp parallel clefts of varying length.
• Bound narrow folds of the mucous
membrane and are the vestige of the
large foliate papillae found in many
mammals.
• They contain taste buds.

34. Filiform Fungiform Circumvallate Foliate
Cone-shaped.
 keratinized Epithelium
 core of C.T from which
secondary papillae
protrude.
No taste buds
 mushroom-like
 Between the fili form
papillae.
 Protrude above the
surface.
 Thin epi show the red
color of the vessels of the
CT
 Few taste buds on the
dorsal surface
 In front of sulcus
terminalis.
 They do not protrude
above the surface
 bounded by a deep
circular furrow.
 Thin epith sometimes
thin k. layer.
 Numerous taste buds on
the lateral surface.
 Von ebner SG open at the
trough
 lateral border of the
posterior parts of the
tongue.
 Sharp parallel clefts of
varying length.

35. Taste buds
Shape:
small ovoid or barrel-shaped intraepithelial
organs about 80 µm high and 40 µm thick.
Histology:
 They extend from the basal lamina to the
surface of the epithelium.
 Their outer surface is almost covered by a few
flat epithelial cells, which surround a small
opening, the taste pore.

36. 1-The outer supporting cells:
arranged like the staves of a barrel or layers
of onion.
2-The inner supporting cells:
shorter &spindle shaped.
3- neuro epithelial cells:
-10 to 12 in no between the inner cells,
-They are the receptors of taste stimuli.
- They are slender, dark-staining cells
- Carrying fingerlike processes at their
superficial end.
By L/M…… resemble hairs
By E/M……fingerlike processes are visible into the
space beneath the taste pore.

37.  A rich plexus of nerves is found below the taste
buds. Some fibers enter the epithelium and end in
contact with the sensory cells of the taste bud.
Taste buds are found in:
1. Inner wall of the trough surrounding the vallate
papillae.
2. Folds of the foliate papillae.
3. Fungiform papillae at the tip and the lateral
borders of the tongue.
4. Posterior surface of the epiglottis.

39. Taste perception

40. Taste perception is a combination of sensory, olfactory signals
and food tactile sensations to produce a specific flavor.
Taste perception

41. Von ebner S.G & other
minor glands
Serous
secretion
Dissolve tastants
During mastication, certain chemicals
in ingested food called tastants are
dissolved in the serous salivary
secretion of Von Ebner's glands as well
as other minor salivary glands.
When the dissolved substance passes through
the taste pore and comes in contact with the
microvilli of the neuroepithelial cells… signals
are transmitted, through the release of
neurotransmitters, to the associated axons,
then afferent nerves .

42.  Sweet at the tip fungiform
 Salty at the lateral border of the tongue
fungiform
 Bitter in the middle at posterior part of the tongue
circumvallate
 Sour in the lateral areas of posterior areas of the tongue
foliate

43. It is small rounded or oval elevations composed of
 lymphatic nodules in the under lying C.T known as lingual follicle which has germinal
center lymphocytes arise from it
 covered by non-keratinized stratified squamous epith folded into crypts.
 Into the bottom of these lingual crypt duct from the Weber minor mucous salivary glands
opened.
Posterior 1/3 of the tongue
(lymphatic, pharyngeal part) Lingual tonsils:

44. Muscles of the Tongue
a)Extrinsic
 Genioglossus Muscle
 Hyoglossus Muscle
 Styloglossus Muscle
b)Intrinstic
 Longitudinal fibers
 Transverse fibers
 Vertical fibers

46. Junctions in the oral
mucosa
Mucogingival
junction
Mucocutaneous
junction
Dentogingival
junction

47. 1. Mucogingival junction
•Clinically
• it is demarcated by the change from the bright pink of the alveolar mucosa
to the pale pink of the gingiva.

48. Histology:
gingiva
 The epithelium of attached gingiva: keratinized
or parakeratinized
 The lamina propria: contains numerous coarse
collagen bundles attaching the tissue to the
periosteum
Alveolar mucosa
 has a thicker non keratinized epithelium
overlaying a loose lamina propria with numerous
elastic fibers extending into the thicker
submucosa.

49. 2.Mucocutaneous junction
Transitional zone of Lip or vermilion border

50. 2.Mucocutaneous junction
Transitional zone of Lip or vermilion border
The lip has 3 surfaces:
 inner mucous membrane.
Transitional zone
Outer skin side.

51. Skin (hairy) side of the lip :
Composed of all layers of k. epith in
addition to stratum lucidum between the
granular & the keratinized layer
It is composed of 2-3 layers of flat cells
permeated by oily material elaidin (block the
penetration of any substance from outside
Skin appendages: sweat glands
sebaceous glands
hair follicle

52. • Thin keratinized epithelium.
• Long connective tissue papillae containing
capillary loops.
• this arrangement brings the blood close to the
surface & accounts for the strong red color.
• The line separating the vermilion zone from the
hair bearing skin of the lip is called the vermilion
border.
Vermelion zone (red zone)

53. • Between the thin keratinized & non
keratinized labial mucosa is an
intermediate zone covered by
parakeratinized epithelium, in
infants this region is thickened
which represent an adaptation to
suckling
Suckling pad
Mucous
membrane

54. Mucous membrane side
Similar to the cheeck mucosa,
 overlying orbicularis oris muscle
Minor salivary glands are present

56. 3.Dentogingival junction
DEF :
 It is the mucosal attachment of the
gingiva to the tooth surface (enamel
& cementum)
 Both compartment of the gingiva
(epithelium & CT) are attached to the
tooth and contribute to the security
of the junction.

57. Length :
From the bottom of the gingival sulcus
toward the C.E.J bout
1-3mm, which is nearly equal to the
length from its apical end to the crest of
alveolar process.

58. DEVELOPMENT OF ATTACHMENT EPITHELIUM
• When enamel is completely formed, the enamel is covered by the 1ry enamel cuticle the
ameloblasts are attached to it by hemi desmosomes.
• The ameloblasts and rest of cells of the enamel organ fuse together to form
Reduced Enamel Epithelium (R.E.E) (for protection)
• The R.E.E separated from the oral epi. By C.T.

59. R. E.E secrete dysmolytic enzymes that breaks up to the connective tissue found in
the way of erupting tooth.
Fusion between the REE & oral epi epithelial plug.
 The central portion of the plug canalizes by cell degeneration.
As the tip of the crown has emerged, the part of gingival epithelium derived from
the reduced dental epithelium is now known the 1ry attachment epithelium.
The Shallow groove that develops between the gingiva and the tooth is called the
gingival sulcus.

60. Histological structure
• Attachment epithelium:
• Non k. s. sq. epithelium 3 to 4 cell
layers that increase by age to 15-30
layer coronally& taper to 1-2 layer
apically.
• The basal cells are cuboidal and are
attached to the underlying
connective tissue by basal lamina
(external basal lamina) and
hemidesmosomes.
• The basal lamina is composed of
lamina lucida and lamina densa.

61. • The cells above the basal layer are flattened
and surrounded by a prominent intercellular
spaces that may contain macrophages,
lymphocytes, and plasma cells can migrate to
the surface indicating permeability of
attachment epith.
• The cells attached internally to the tooth
structure by internal basal lamina &
hemidesmosomes.
• These cells have high rate of turn over so the
basal cells divide to give new cells that migrate
to the surface to replace the shed cells in the
Gingival sulcus.

62. C.T of dento gingival junction:
Insertion of the gingival fibers of the PDL in this
region give strength to this area.
It differ from the C.T of the gingiva in :
1- Less amount of collagen fibers under
the basal lamina.
2-There is always evidence of inflamatory
cells even in normal condition they even
pass into the epithelium and the sulcus
and may also appear in the oral fluid.

63. Epithelial attachment (mode of attachment)
• It is the firm union of epithelium to the tooth surface it is achieved by
the basal lamina material (400 A) thickness to which the hemi
desmosomes are attached.
• First : secreted by the ameloblast & called primary enamel cuticle
which attach the primary attachement epi ( from R.E.E) to the tooth
surface.
• later: 1ry attachment epi replaced by oral epi and called 2ry
attachment epi which secretes 2ry enamel cuticle to attach to the
tooth.

64. • Active eruption: The physiologic eruptive movement of the tooth that
leads to the movement of the tooth in occlusal direction.
• Passive eruption: Gradual downward movement of the attached
epithelium apically causing exposure of the remaining portion of the
crown and may even cementum.
MIGRATION OF ATTACHMENT EPITHELIUM

65. • The bottom of the gingival sulcus is
located on enamel.
• Apical end of attachment epithelium
stays on the CEJ.
• In primary dentition almost up to one year
of age before shedding.
• In permanent dentition usually to the age
of 20 or 30 years.
• Anatomical crown is larger than the
clinical crown.
First stage:

66. Second stage:
• The bottom of the gingival sulcus is
still on enamel.
• The apical end of the attachment
epithelium has shifted to cementum
surface.
• Till the age of 40 years of age or may
even later.
• The anatomical crown is still larger
than the clinical crown.

67. Third stage:
• The bottom of the gingival
sulcus is at the CEJ.
• Epithelial attachment is entirely
on cementum.
• The anatomical crown is equal
to the clinical crown.

68. Fourth stage:
• The entire attachment epithelium and the
gingival sulcus lie in cementum.
• The gingival recession is related to the
advancement of the previous stage.
• The anatomical crown is less than clinical
crown.

70. Clinical consideration
1- old age people:
softer dryer , atrophic& friable mucosa with thinner epithelium and
flatter retepigs.
Reduction in number of filiform papillae.
Post menopausal women complain from dryness of the mouth and
burning sensation & abnormal taste.

71. Fordyces spots Varicose veins or
caviar tongue.

72. 2-taste sensation may be affected by:
 Head injuries due to nerve affection.
Chemotherapy &radiotherapy(affect taste buds – xerostomia)
Antidepressant & antihistaminic (dry mouth )
B blockers: affect taste and smell sensation.
ACE inhibitors: metallic taste.