1. ORAL MUCOSA

2. ORAL MUCOSA
The oral cavity is lined with an
uninterrupted mucous membrane, which is
continuous with the skin near the vermilion
border of the lips and with the pharyngeal
mucosa in the region of the soft palate and
anterior pillars of fauces.
The epithelium of the oral mucosa
originates partly from the ECTODERM
(lips, vestibule, gingiva, cheeks, palate,
floor of the mouth), and pertly from the
endoderm (tongue).

3. MASTICATORY MUCOSA – free and
attached gingiva and hard palate comes in
primary contact with food during mastication
and is keratinized.
LINING MUCOSA – the lips cheeks, vestibule,
floor of the mouth, interior surface of the
tongue and soft palate. It does not function in
mastication and therefore has little attrition. It
is soft, pliable and non-keratinized.
SPECIALIZED MUCOSA – on the dorsal
surface (dorsum) of the tongue. It is covered
with cornified epithelial papillae.

4. Functions of the Oral Mucosa
Protection – acts as major barrier to
microorganisms
Sensation – receptors that respond to
temperature, touch, pain, taste; initiates reflexes
such as swallowing, gagging and salivation
Secretion – saliva, contributes to the maintenance
of moist surface
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

5. General Histologic Characteristics
of Oral Mucosa
Two main tissue components:
Oral epithelium – stratified squamous
epithelium
Lamina Propia or Corium – undderlying
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

6. Basement Membrane – structureless
layer about 1 – 2 micrometers thick;
interface between epithelium and
connective tissue
Connective tissue papilla - irregular and
upward projections of connective tissue
Rete Ridges – or rete pegs, epithelial
ridges or pegs that interdigitate with the
connective tissue papilla

7. RETE RIDGES
BASEMENT LAMINA
CONNECTIVE
TISSUE PAPILLA

8. Histologic Characteristics of the
Surface Epithelium
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

9. Incomplete Keratinization - Least common
type, approximately 7-10% of cases and is
seen only in the region of the marginal
gingiva. Stratum corneum is homogenous
and consists of 2 cell types, which
occasionally form 2 superimposed layers:
the first type of cell is the same as cornified
cell of a parakeratinized stratum corneum;
the 2nd type is different from keratinized
cells and seems to reach the stratum
corneum and its surface without being
transformed into a keratinized cell.

10. Layers of the Keratinized Surface
Epithelium
Stratum corneum
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
up to 20 layers of squames and is
thicker than that of most of the skin
except the soles and palms

11. Stratum Granulosum ( granular layer)
larger flattened cells containing
small granules called keratohyalin
granules
some regions of the masticatory
oral epithelium (e.g. gingiva) it is
difficult to see the granules under
the light microscope

12. Stratum spinosum (Prickle-cell layer)
several rows of larger elliptical or
spherical 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
Stratum Basale ( Basal layer)
cuboidal to columnar cells adjacent to
the basement membrane

13. Layers of Non-Keratinized Surface
Epithelium
Stratum Basale
Cuboidal or columnar cells containing
separate tonofilaments and other cell
organelles
Site of most cell divisions
Stratum Intermedium
Slightly increase in cell size as well as
accumulation of glycogen in cells of the
surface layer
On rare occasion, keratohyalin granules
can be seen

14. 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

15. Layers of Lamina Propia/Corium
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)

16. Subdivisions of the Oral
Mucosa

17. Lining Mucosa

18. Lips
Lined by a moist, stratified squamous
non-keratinized epithelium
Non-keratinized mucosa is
distinguished by a red border known
as vermilion border
This area is at the junction between
the oral mucosa and the skin of the
lips, becoming modified into
keratinized epihtelium

19. Three reasons why vermilion border is
red:
Epithelium is thin
This epithelium contain eleidin, which
is transparent
The blood vessels are near the
surface of the papillary layer

20. Soft Palate
Stratified squamous non-keratinizing
epithelium – highly vascularized
More pink than the mucosa of the
keratinized hard palate – lamina
propia contains many small blood
vessels
Beneath the CT of the lamina propia
is the submucosa which contains
muscles and mucous glands

21. Cheeks
Mucosa is same as the lips and soft
palate, however, the submucosa
contains fat cells and mixed glands
(seromucous) located within and
between the muscle fibers
The presence of these glands is a
unique feature of the cheeks

22. Ventral Surface of the Tongue
Lining mucosa also contains lamina
propia and submucosa
In the submucosa, muscle fibers are
located under the surface of the
tongue
The entire area exhibits dense,
interlaced muscle and CT fibers

23. Floor of the Mouth
Non-keratinized mucous membrane
Covering appears loosely attached to
the lamina propia in contrast to the
mucosa of the ventral surface of the
tongue which is firmly attached
Presence of minor salivary glands
and right and left major mucous
glands, the sublingual glands

24. Masticatory Mucosa

25. Gingiva or Marginal Epithelium
part of the oral mucosa and at the
same time, the most peripheral part
of the tooth-supporting apparatus.
It covers the coronal part of the
alveolar process, passes over the
crest of the alveolar bone and
interdental septa and encircles the
necks of teeth

26. Gingiva or Marginal Epithelium
Histological Characteristics of a Normal Marginal
Periodontium
“free” gingiva ends on the enamel surface at a
shallow angle
Gingival sulcus is less than 0.2 mm depth or is
absent
The junctional epithelium contains only a few
isolated leukocytes
Collagen Ct fibers extend directly alongside the
junctional epithelium all the way to just under the
gingival margin
No signs of acute inflammation or chronic cellular
infiltration

27. Clinical Characteristic of Normal Gingiva
A pale, pink color
A smooth marginal and papillary gingiva
Attached gingiva with distinct stipples in varying
density.
Firm consistency of all the tissues.
The papillary gingiva reaches halfway to the
incisal edge and fills the interdental space up to
contact point.
a fine probe without the use of apparent force.
Sulcular fluid cannot be obtained on filter paper
strips placed into the entrance to the sulcus

28. Gingiva or Marginal Epithelium

29. Normal gingiva that satisfies
these criteria is not identical with
“clinically healthy” gingiva

30. Two topographycally distinct zones:
Free gingiva
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

31. has an epithelial attachment maintained
by junctional epithelium along the tooth
surface
Separated from the attached gingiva by
a slight indentation called the FREE
GINGIVAL GROOVE, whose level
corresponds approximately to that of the
bottom of the gingival sulcus
about 1.1 mm in the primary dentition,
about 1.5 mm, 0.8 – 1.8 mm in young
adults and about 1.6 mm (0.9-2.1 mm) in
older people

32. Marginal gingiva - that part of the free
gingiva that tapers to a knife-like edge
extending along the cervical level of the
tooth on labial or buccal and lingual
surfaces
Interdental gingival papilla – the bulges
of gingival tissue on al occlusal direction
in between teeth
Interdental col – the constriction in
between the facial and lingual interdental
gingival papilla

33. 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
Attached Gingiva
Is part attached to the teeth and alveolar
bone. It is bounded CORONALLY by
the free gingival groove and APICALLY
by the mucogingival junction

34. On the facial surface of both jaws, it is
adjacent to the alveolar mucosa
On the lingual surface of the mandible it
is adjacent to the floor of the mouth
The is NO attached gingiva on the
palatal side of the maxilla since the
immovable palatal mucosa extends all
the way to the free gingiva
Exhibits many ovoid or elongated
indentations called STIPPLES – reflects
the arrangement, thickness and
frequency of the rete ridges

35. Density varies between individuals
Especially pronounced on the anterior
region of the maxilla
Absent in children younger that 6 years;
and is present only 35% of children aged
5 – 13 years

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

37. Dentogingival Junction
Represents a unique anatomic
feature concerned with attachment of
the gingiva to the tooth
Ectodermal in origin
Consist of fundamental 3
compartments:
Junctional epithelium
Oral sulcular epithelium
Oral gingival epithelium

38. Gingival Ligament or Supra-
Alveolar Fiber Apparatus
Dentogingival fibers
Dentoperiosteal fibers
Alveologingival fibers
Circular an Semicircular fibers
Transeptal fibers
Transgingival and Intergingival fibers
Interpapillary fibers
Periosteogingival fibers
Intercircular gibers

39. 1. Dentogingival fibers
The most numerous, consists of three
groups:
First group extends from the cementum
in an obliquely coronal direction
Second group streams horizontal from
the cementum into the free marginal
gingiva
Third group, many of which run parallel
with the dentoperiosteal fibers, curve
from the cementum apically over the
alveolar crest

40. 1. Dentogingival fibers
FIRST
SECOND
THIRD

41. 2. Dentoperiosteal Fibers
Insert into the supra-
alveolar cementum at
the same level as the
transeptal fibers, pass
apically over the crest
of the alveolar bone
into the periosteum of
the outer and inner
plates of the alveolar
process

42. 3. Alveologingival fibers
Insert into the crest
of the alveolar
bone, course
coronally and enter
the free and
attached sections
of the marginal and
interdental gingiva

43. 4. Circular and Semicircular fibers
Circular – small group
of fibers that forms a
band around the neck
of the tooth helping to
bind the free gingiva
into the tooth
Semicircular – encircle
only the vestibular or
oral half of the root; lie
apical to the circular
fibers

44. 5. Transeptal Fibers
Also called
INTERDENTAL
FIBERS
Bind the supra-
alveolar cementum of
one tooth to that of the
adjacent tooth
Implicated as a major
cause of post retention
relapse of
orthodontically
positioned teeth

45. 6. Transgingival and Intergingival fibers
– reinforce the circular and semicircular
Transgingival –
identical with
semicircular, insert
interdentally into a
supra-alveolar
cementum, pass
obliquely through the
interdental tissue
stream into the free
gingiva of the adjacent
tooth where they may
unite with the circular
fiber

46. 6. Transgingival and Intergingival fibers
– reinforce the circular and semicircular
Intergingival – form
a continuous series
of fibers running
under the
epithelium along
both the vestibular
and oral aspects of
the dental arch
converging distal to
the last molar

47. 7. Interpapillary fibers
Cross through the
free portion of
interdental gingival
tissue in an
orovestibular
direction to tie the
oral and vestibular
gingival papillae
together

48. Periosteogingival fibers
Insert into the periosteum of the outer
and inner cortical plates of the
alveolar process and pass facially
and orally into the section of all
attached gingiva lying over it
Intercircular fibers
Are located on the vestibular and oral
sides of the interdental gingiva and
connect the circular fiber bundles of
neighboring teeth. They form part of
the Intergingival fiber bundles

49. 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
The alveolar mucosa is movable, can be
lifted to a limited extent from its base and
exhibits structural deep red in color and
has a smooth surface

50. Hard Palate
Is the roof of the mouth and is
supported by the palatine processes
of the maxillary and horizontal parts
of the palatine bone
At the level of the alveolar tuberosity,
it joins the soft palate
The hard palate is pale pink

51. On the surface of the hard palate, the midline is
known as MEDIAN RAPHE - fusiform mucosal
mass and forming the midline of the palate and
represent the fusion area of the palatine
processes
INCISIVE PAPILLA - oral mass of tissue capping
the opening of incisive canal containing oral part of
the nasopalatine duct
On each side of the median raphe are ridges of
tissue called TRANSVERSE RIDGES OR
PALATINE RUGAE AND RUGAE PALATINI -
ridges of mucous membrane with dense
connective tissue core extending laterally from the
incisive papillae and the anterior raphe

53. Specialized Mucosa

54. Dorsum of the tongue
Covered by a stratified squamous
keratinizing epithelium
Consists of four types pf epithelial
structures called papilla:
Filiform papilla – most numerous;
arranged in rows
Fungiform papilla – fewer, distributed
along the filiform; numerous near the
tips of the tongue; contains taste buds

55. Circumvallate papilla –
distributed along the
V-shaped sulcus
between the body and
the base; 3 mm in
diameter; contains
taste buds
Foliate papilla – 4 – 11
vewrtical grooves or
furrows on the lateral
posterior sides of the
tongue; contains taste
buds

56. Taste Buds
Microscopically visible barrel-shaped
bodies
Contains the chemical sense of taste
Generally associated with the papilla
of the tongue – circumvallate, foliate,
and fungiform, although some are
distributed in the soft palate,
epiglottis, larynx, and pharynx

57. Types of taste cells – found among
the 10 – 14 cells in the taste bud
Supporting or Sustentacular cells
Tall columnar cell; lie at the periphery of
the taste bud
Taste cells/chief cells – tall columnar
cells that bear either elongated microvilli
that project into the taste pore or ones
with shortened villi that open into the
base of the pore
Each are associated with nerves

58. Basal cells
Are in close proximal contact with the
basal lamina
Rapid turn-over of cells in the taste
bud – approximately 10 days
Four taste sensations are sweet,
salty, sour and bitter

60. Location of taste perception on the
tongue and soft palate