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GINGIVA 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- 1
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GINGIVA (2) / orthodontic courses by Indian dental academy

May 10, 2017

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Page 1: GINGIVA (2) / orthodontic courses by Indian dental academy

GINGIVA 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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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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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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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

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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.

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).

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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.

- 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

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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.

1) Various anatomic variations of the interdental col in the normal

gingiva and after gingival recession

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

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.

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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.

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).

Later

The principle cell is the keratinocyte.

- Proliferation takes place by mitosis.

- Differentiation involves the process of keratinization.

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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.

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

- Partial / incomplete keratinocyte

- Pyknotic nuclei

- No keratinocyte

- No corneum / granulosum

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- Well defined St. granulosum e.g. layers of outer gingival epithelium

in st corneum

- Keratinohyaline granules

- No st granulosum e.g. most areas of gingival epithelium

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.

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.

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STRUCTURE AND 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.

- 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.

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- 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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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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Functions

- Unlike the epithelial connective tissue interface, the lamina densa of

the internal basal layer (facing the enamel) has no anchoring fibrils

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

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.

Collagen Type I

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- 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.

GINGIVAL FIBRES Carranza (1996)

- Gingiovodental.

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- Circular.

- Transeptal.

- Semicircular

- Transgingival

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

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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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Lymphatic drainage

- Brings in the lymphatics of the C.T. papillae. It progresses to the

regional lymph nodes.

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

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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.

- Exposure of the tooth by the apical migration of gingiva is called

gingival recession / atrophy Physiologic /Pathologic occurs.

References:

1. Clinical Periodontology by Carranza, Newman and Takei.2. Periodontics by Grant, Stern and Listgarten.

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Gingiva

SEMINAR BYDr. N.Upendra Natha Reddy

Postgraduate Student 2004-2007

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Contents

1. Definition

2. Function

3. Development

4. Normal Clinical Features

5. Gingival Fluid / Sulcular Fluid (Gcf)

6. Normal Microscopic Features

7. Structure and Characteristics Of Gingival Epithelium

8. Gingival Fibers

9. Blood supply* Nerve supply * Lymphatic drainage

10. Normal clinical features and microscopic features

11. References

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