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1. The periodontium (peri-around, dontium-tooth, greek) consists of
investing and supporting tissues. The investing tissue of the periodontium
is known as the GINGIVA. It is the most peripheral portion of
periodontium at large.
According to the Dorland Medical Dictionary, the word gingiva
means the ‘gum of the mouth’. It is that part of the oral mucosa overlying
the crown of unerupted teeth and encircling the necks of these that have
erupted, serving as the supporting structure for the subadjacent tissues.
DEFINITIONS
1. CARANZA
Is the part of oral mucosa that covers the alveolar processes of jaw
and surrounds the neck of teeth.
2. SCHROEDER
It is a combination of epithelium and connective tissue and is
defined as that portion of oral mucous membrane, which in complete post-
eruptive dentition of a healthy young individual, surrounds and is attached
to the teeth and the alveolar processes.
3. GRANT
Is the part of oral mucous membrane attached to the teeth and the
alveolar processes.
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2. 4. LINDHE
Is that part of masticatory mucosa covering the alveolar processes
and the cervical portions of teeth.
FUNCTIONS
As the gingiva represents both the masticatory mucosa as well as the
most peripheral part of the periodontium, its functions are two fold.
I] As part of the oral mucosa
It protects the supporting tissues from the oral environment.
a) As part of oral mucosa, it is subjected to friction and pressure in the
masticatory process. Its densely collagenous lamina propria,
peripheral sensory innervation and keratinization help in the
adaptation to these physical requirements.
b) It is a mucostable tissues because of its firmness, scalloped contour,
close adaptation and attachment to the underlying structures.
c) Gingival tissues fulfill the functions of sensitivity and resistance.
II] As part of the periodontium
The gingiva exhibits functional properties:
a) It ensures dental arch linkage and controls the positioning of teeth in
the horizontal plane by means of its supra-alveolar fibre apparatus.
These fibres along with those of PDL secure teeth against rotational
forces and generate forces resulting in mesial drift.
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3. b) It maintains gingival and periodontal health by means of various
defense mechanism operating within the gingival tissues.
This peripheral defense action of gingiva has two arms:
1. The humoral arm which represents the generation of gingival
fluid.
2. The cellular arm which represents the continuous irrigation
of neutriphilic granulocytes via the junctional epithelium.
Both these arms keep a 24 hour watch on the periodontal health.
Development
Unlike, the other tissues of the periodontium which are derived from
the ectomesenchymal dental follicle, the gingiva is a derivative of
mesoderm.
According to Schroeder, the shape, topographical distribution and
width of the gingiva are functions of the presence and position of erupted
teeth.
He also says that, there are reasons to assume that the gingival
tissues exist and develop as a site specific portion of the oral mucous
membrane prior to the eruption of deciduous teeth. Thereafter, the gingiva
although increasing size serves both deciduous and permanent teeth.
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4. Normal Clinical Features
Gingiva is divided into:
Oral part Vestibular part
Anatomically, it has been divided into:
- MARGINAL gingiva
- ATTACHED ginigiva
Pyramidal
- INTERDENTAL gingiva
Col
A] Marginal gingiva / Free gingiva / Margio Gingivalis
Definition
It is the terminal edge or border of the gingiva surrounding the teeth
like a collar.
Figure
It is demarcated from the adjacent attached gingiva by a shallow
linear depression – the free gingival groove. This is about 1mm wide and
forms the soft tissue wall of the gingival sulcus. According to Schroeder,
the term ‘free gingiva’ is a clinical designation and relates to the clinical
property of the gingival rim.
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5. B] Attached Gingiva
It is continuous with the marginal gingiva. It is firm, resilient, and
tightly bound to the underlying tissues of the alveolar bone. On the facial
aspect, the attached gingiva extends to the relatively loose and movable
alveolar mucosa from which it is demarcated by the mucogingival junction
(3 M G Lines)
Facial maxillary Facial mandibular Lingual mandibular
# Lingual maxillary is not seen as there is not alveolar mucosa on
the palate and the palatal tissue is firmly attached to the bone.
Width of the attached gingiva
Is defined as the distance between the mucogingival junction and
the projection on the external surface of the bottom of the gingival sulcus /
periodontal pocket.
It is generally greatest in the incisor region (3.5 – 4.5mm in maxilla
and 3.3 – 3.9mm in mandible) and less in the posterior region with least in
the 1st
premolar area (1.9mm in maxilla and 1.8mm in mandible).
The width of the attached gingiva increases with age and
supraerupted teeth.
Reduced / Absent Attached gingiva may be due to:
- base of the pocket is close to the mucogingival line.
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6. - frenal / muscle attachments that encroach on pockets and pull them
away from the tooth surface.
- denudation of root surfaces.
Adequacy of the attached gingiva can be determined by the
TENSION TEST which consists of retracting the cheeks and lips laterally
with fingers and checking if such tension polls the marginal gingiva from
the teeth. Reduced width of attached gingiva can be corrected with
mucogingival surgeries.
C] Interdental Gingiva
It occupies the gingival embrasure, which is the interproximal space
beneath the area of tooth contact
Types:
Pyramidal Col
 Where there is one papilla with
its tip immediately beneath the
contact point.
 Which represents as a depression
that connects a fascial and a lingual
papilla and conforms to the shape of
interproximal contact.
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7. Various anatomic variations of the interdental col in the normal
gingiva and after gingival recession
1) Mandibular anterior
2) Mandibular posterior
GINGIVAL SULCUS
- Is the shallow space / crevice around the tooth bounded by the
surface of the tooth on one side and epithelium lining the free
margin of the gingiva on the other.
- It is V-shaped and rarely permits the entrance of a periodontal
probe. Under normal circumstances, the depth is 0
In histologic sections – 1.8mm. The probing depth is 2-3mm
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8. GINGIVAL FLUID / SULCULAR FLUID (GCF)
 The gingiva sulcus contains a fluid that seeps into it from the gingival
connective tissue through the thin sulcular epithelium.
Function of GCF:
- cleanses material from the sulcus.
- Contains plasma proteins that may improve adhesion of the
epithelium to the tooth.
- It also possesses antimicrobial properties.
- It exerts antibody activity in defense of the gingiva.
DEVELOPMENT OF GINGIVAL SULCUS
After the enamel formation is complete and before the tooth begins
its eruptive movement, the crown of the tooth is covered by a double layer
of cells (ameloblasts and remnants of dental organ)  Reduced enamel
epithelium (R.E.E.).
Between the R.E.E. and the overlying oral epithelium, is the
connective tissue that supports R.E.E. and the oral epithelium.
R.E.E.  OL and IL
OL – flattened cells – remnants of dental organ (outer layer).
IL Ameloblasts (inner layer)
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9. When tooth eruption begins, this connective tissue breaks down. In
response to these degradative changes, the cells of OL of R.E.E. and basal
cell of oral epithelium proliferative and migrate into the degenerating
connective tissue and eventually fuse to form a mass of epithelial cells
(epithelial cuff) over the erupting tooth (epithelial plug).
From this epithelial cuff, together with the remaining reduced
enamel epithelium, the epithelial component of the dentogingival junction
is established in relation to a degraded connective tissue. The cells of the
cuff epithelium proliferates and migrates and becomes separated by
widened intercellular spaces. It is through these spaces that antigens from
the oral cavity pass as soon as tip of the cusp emerges, initiating an acute
inflammatory response in the already altered c.t. supporting the epithelium.
The clinical manifestations of this inflammatory response is called
teething.
Once the tip of the cusp emerges, oral epithelium cells begin to
migrate partially over the reduced enamel epithelium, in an apical direction
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10. and at this time, the attachment of the gingival epithelium to tooth is
maintained. This is primary epithelial attachment (by ameloblasts).
Because of the continuing cell division, the ameloblasts are
eventually displaced by the newly formed daughter cells. As the
overgrowing epithelial cells from the cuff stratify, they further separate the
cells of the transformed dental epithelium from the nutritive supply, with
consequence that these latter cells degenerate and create a Gingival Sulcus.
NORMAL MICROSCOPIC FEATURES
The gingiva consists of a central core of c.t. (lamina propria)
covered by stratified squamous epithelium.
Gingival Epithelium
From the morphologic and function points of view 3 different types
are seen.
Oral / Outer Sulcular Junctional
Functions
To protect the deep structures while allowing a selective interchange
with the oral environment (achieved by proliferation and differentiation of
keratinocytes).
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11. Later
The principle cell is the keratinocyte.
- Proliferation takes place by mitosis.
- Differentiation involves the process of keratinization.
The main morphologic change is the progressive flattening of the
cell.
3 types of keratinization can be seen:
Histologically, a keratinized epithelium shows a number of distinct
layer.
I] St Corneum
It is the surface of very flat eosinophilic cells.
II] St Granulosum
Larger flattened cells that contain kerato-hyaline granules. The upper most
layer of stratified spi contains numerous granules called keratinosomes /
odland bodies.
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12. III] St Spinosum / Prickle cell Layer
Larger elliptical / spheroidal cells. When prepared for histologic
sections, these cells shrink away from one another remaining in contact
only at patients known as intercellular bridges / desmosomes.
IV] St Basale
Proliferative layer.
3 types
Ortho Keratinocyte Para Keratinocyte Non-keratinocyte
- Complete
keratinocyte
- No nuclei in st
corneum
- Well defined St.
granulosum e.g.
layers of outer
gingival epithelium
- Partial /
incomplete
keratinocyte
- Pyknotic nuclei
in st corneum
- Keratinohyaline
granules
- No st granulosum
e.g. most areas of
gingival epithelium
- No keratinocyte
- No corneum /
granulosum
Keratinization
The prot syn during maturation process – keratolinin and involved
in form an envelope below the cell membrane (chemically resistant
structure). As the cells reach the corneum keratin or disappear and give rise
to a protein – fillagirin which forms the matrix of the most differentiated
epithelial cells – CORNEOLYTE.
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13. Cell type Level in epithelium Functions
1. Melanocyte
2. Langerhans
cells
3. Merkels cells
Basal
Predominantly
suprabasal
Basal
Synthesis of melanin
pigment
Regulatory cell
Macrophage
(contain Birbeck’s
granules)
Tactile perception
Both epithelial proliferation and maturation are needed for
continuous cell renewal to maintain structural integrity.
The control over these two processes is mediated by substance
produced by maturing epithelial cells – CHALONES which acts by –ve
feedback mechanism.
STRUCTURE AND METABOLIC CHARACTERISTICS OF
GINGIVAL EPITHELIUM
I] Oral / outer epithelium
It covers the crest / outer surface of the marginal gingiva and the surface of
the attached gingiva. It is keratinized / parakeratinized or present various
combinations of these conditions. The prevalent surface is however
parakeratinized.
- In orthokeratinized areas  Keratins K1, K2 and K-10, K-12 which
are specific for epidermal differentiation are expressed with high
intensity.
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14. - K6 and K16  characteristic of highly proliferative epithelium K1,
K2, K-10, K-12 – expressed with low intensity in parakeratinized
area.
These also express K-19 which are absent from Ortho keratinized
area.
II] Sulcular epithelium
- Lines the gingival sulcus.
- It is a thin, non-keratinized squamous epithelium without retepegs,
which extends from the coronal limit of junctional epithelium to the
crest of the gingival margin.
- It shows cells and with hydropic degeneration.
- It contains keratins K4 and K13, also expresses K-19. It lacks
stratum granulosum and corneum, cytokeratins K1 and K2 and K10-
K12 and also lacks Merkels cells.
It has the potential to keratinize, if:
a) It is reflected and exposed to the oral cavity.
b) The bacterial flora of the sulcus is totally eliminated.
These findings suggest that the local irritation of the sulcus (due to
its contact with tooth) prevents sulcular keratinization.
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15. Functions of sulcular epithelium
It acts as a semi-permeable membrane three which injurious
bacterial pass into the gingiva and three which tissue fluid from the gingiva
seeps into the sulcus.
III] Junctional epithelium
- Consists of a collar-like band of stratified squamous non-
keratinizing epithelium.
a) It is 3-4 layers thick in early life, but it increases with age to 10-20.
b) The length ranges from 0-25 – 1.35 mm.
c) It is widest in its coronal portion (15-20 cell layers) but becomes
thinner towards the CEJ.
d) It expresses K-19 and the stratification specific cytokeratins K5 and
K14.
Histology of junctional epithelium
Is a continuous self-renewal structure and is continuously renewed
through cell division occurring in the basal layer. The cells migrate to the
base of the gingival sulcus, from where they are shed.
Cells are arranged in 2 strata
Basal Suprabasal
Both are flattened with their long axis 11 to the tooth surfaces
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16. 3 zones have been identified in the junctional epithelium
Apical Middle Coronal
Shows cells with
germinative
characteristics
Zone of major
adhesiveness
Zone of greater
permeability
Attachment of junctional epithelium is attached to the tooth surface
(epithelial attachment) by means of an internal basal lamina (300-400 A°
thick and lies 400 A° beneath the epithelial basal layer) laminin, basement
membrane glycoprotein.
Lamina lucida lamina densa (adjacent to the enamel)
It attached to the connective tissue by means of an external basal
lamina.
Functions
- Unlike the epithelial connective tissue interface, the lamina densa of
the internal basal layer (facing the enamel) has no anchoring fibrils
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17. attached to it, which means that the junctional epithelium is
physically attached to the tooth via the hemidesmosomes
(Schroerder).
- The attachment of the junctional epithelium to the tooth is further
reinforced by the gingival fibres which brace the marginal gingiva
against the tooth surface for this reason.
Junctional epithelium and gingival fibres are a function unit
DENTOGINGIVAL UNIT
Difference between
Junctional epithelium Oral epithelium
- The size of the cells relative
to the tissue volume is larger.
- The intercellular space
relative to the tissue volume
is larger.
- The number of desmosomes
is smaller.
- Epithelial retepegs and
connective tissue papillae are
lacking at the junctional
epithelial c.t. interface.
- Non keratinized.
- Is smaller.
- Is smaller.
- Is larger.
- They are present.
- Keratinized / parakeratinized.
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18. GINGIVAL CONNECTIVE TISSUE
Known as lamina propria (2 layers)
Papillary layer Reticular layer
Lies to the subjacent epithelial and
consists of papillary projections
between the epithelial retepegs.
Which is contiguous with the
periosteum of the alveolar bone.
The c.t. consists of :
- Cells – 5% (mainly fibroblasts).
- Fibres – 60% (mainly collagen).
- Vessels, nerves and matrix – 35%.
Cells
- Fibroblasts are stellate / elongated with abundant rough E.R.
- They are distributed throughout the lamina propria.
The other cells present are:
Histocytes
Macrophages.
Monocytes
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19. Mast cells
Polymorphonuclear leukocytes
Neutrophil
Lymphocyte
Plasma cells
FIBRES
- The connective tissue fibres are:
Collagen Reticulum Oxytalan Elastic
Collagen – 65% of C.T. volume
Tropocollagen (smallest unit of a collagen are aggregated
longitudinally to form molecule) after synthesis, it is secreted out from the
fibroblasts into extracellular space.
Protofibril laterally aggregates to in II form collagen fibrils with an
overlapping of tropocollagen mole by about 25% of their lengths.
- These are bundles of collagen fibrils, aligned in such a way that
fibres exibit a cross-binding.
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20. Collagen Type I
- Forms the bulk of lamina propria and provides tensile strength.
- Gingival collagen fibres – consists of Type I collagen.
Functions:
- To brace the marginal gingiva firmly against the tooth.
- To provide rigidity necessary to without and the forces of
mastication without being deflected from the tooth surfaces.
- To unlike the free marginal gingiva with the cementum of the root
and the adjacent attached gingiva.
Reticulum
- Are present at the epithelial connective tissue and the endothelium
c.t. interface.
Oxytalan
- are present in all c.t. structure of the periodontium and are composed
of long thin fibrils. They regulate vascular flow. In the PDL, these
fibres run 11 to the root surfaces in a vertical direction and bend to
attach to cervical 3rd
of cementum.
- Are present in all C.T. of gingiva and periodontal only in
association with the blood vessels.
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21. GINGIVAL FIBRES
I] According to Grants
a) Dentogingival group :
These fibres extend from the cementum apical to the junctional
epithelium and coarse laterally and coronally into the lamina propria of
the gingiva.
b) Alveogingival :
Arise from the alveolar crest and insert coronally into the lamina
propria.
c) Circular
These encircle the teeth.
d) Transeptal
Is a group of prominent horizontal fibres that extend
interproximally between adjacent teeth.
e) Dentoperiosteal
Extends from the tooth passing over the alveolar crest to blend
with fibres of the periosteum of the alveolar bone.
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22. f) Semicircular group
Run from the distal / mesial root surface of a tooth and extend
around the oral / vestibular surface to insert on the opposite side of
the same tooth.
g) Transgingival
From the proximal root surface they radiate three the embrasures
to blend with the fibres of the oral / vestibular surfaces.
h) Intergingival
They run 11 to the dentition on oral / vestibular surfaces.
II] Carranza (1996)
- Gingiovodental.
- Circular.
- Transeptal.
- Semicircular
- Transgingival
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23. MATRIX
- Constitutes the environment for the cell. It is produced by
fibroblasts and is composed of protein polysaccharides and
macromolecules.
Proteoglycans Glycoproteins
BLOOD SUPPLY
3 sources of blood supply to gingiva (Carranza 1996).
a) Supra-periosteal arterioles
Along the fascial and lingual surface of the alveolar bone, from
which capillaries extend along the sulcular epithelial and between the
retepegs of the external gingival surface.
b) 2 vessels of the PDL – which extend into the gingiva anastomose
with capillaries in the sulcus area.
c) Arterioles which emerge from crest of the interdental septa.
Nerve supply region Innervation
- Upper gingiva Anterior, post and middle
supraalveolar branches of maxillary
nerve, palatal nerves.
Lower gingiva buccal and lingual Infection alveolar branch of
mandibular nerve, buccal branch of
mandibular nerve, sublingual branch
of lingual nerve.
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24. Lymphatic drainage
- Brings in the lymphatics of the C.T. papillae. It progresses to the
regional lymph nodes.
Cuticular structure on the tooth
- The term cuticle is used to describe a thin, acellular structure with a
homogenous matrix sometimes enclosed within clearly demarcated
linear borders.
Classification (Listgarten)
1) Acquired coatings of exogenous origin
- Like saliva, calculus and surface stains.
2) Coatings of developmental origin
- Are those normally formed as part of tooth development after
enamel form is completed, the ameloblastic epithelial becomes
reduced to 1-2 layers that remnants attached to the enamel surfaces
like:
a) R.E.E.
b) Coronal cementum.
c) Dental cuticle
In animal, the R.E.E. disappear very rapidly thereby placing the
enamel in contact with c.t. whose cells then deposit a thin layer of
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25. cementum. In humans, a thin layer of afibrillar cementum may be seen on
the cervical % of crown.
Consists of a layer of homogenous organic material of variable
thickness (0.25µm), overlying the enamel surface. It is non-mineralized
and not always present. Studies have shown the dental cuticle to be protein
across and it may be an accumulation of tissue fluid components.
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26. CO-RELATION OF NORMAL CLINICAL FEATURES AND
MICROSCOPIC FEATURES
Appearance in
health
Changes in
disease / clinical
appearance
Causes for
changes
1. Colour Uniformly pale
pink / coral pink
Variations in
pigmentation
related to race
a) Chronic –
bluish pink /
bluish red
- Vessels
engorged
- Blood flow
sluggish and
- Venous
return impaired
2. Size Not enlarged fits
snugly around the
tooth
Enlarged - Edematous
inflammatory
fluid, cellular
exudates
hemorrhage
3. Shape a) Marginal
gingiva : Knife
edge, follows a
curved line
around the tooth
Rolled / rounded Inflammation
changes, edema
or fibrosis
4. Consistency Firm Soft, spongy, red
colour, dents
readily when
pressed with a
probe, smooth
and shiny surface
Edematous
fluid between
cells in the
connective
tissue
5. Surface texture Represents that of an orange pell and is known as stippling.
The attached gingiva is stippled – not the marginal.
It varies with age, is absent in infancy increase till adulthood
and disappears in old age.
It is produced by alternate protruberances & depressions in
the gingival surfaces.
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27. - Exposure of the tooth by the apical migration of gingiva is called
gingival recession / atrophy.
Physiologic Pathologic
- occurs with age - When excessive exposure
occurs.
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