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DEPARTMENT OF CONSERVATIVE &ENDODONTICS GIN GIVA Seminar Presented By
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GINGIVA 1 / orthodontic courses by Indian dental academy

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Page 1: GINGIVA 1 / orthodontic courses by Indian dental academy

DEPARTMENT OF CONSERVATIVE &ENDODONTICS

GINGIVA

Seminar Presented By

Dr. Krishna Rao Kilaru Post Graduate Student.

S.D.M.COLLEGEOFDENTALSCIENCES&HOSPITAL,

DHARWAD, KARNATAKA, INDIA.

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GINGIVA

CONTENTS:

1) INTRODUCTION2) DEFINITIONS3) DEVELOPMENT OF GINGIVA 4) NORMAL CLINICAL FEATURES MARGINAL GINGIVA. ATTACHED GINGIVA INTERDENTAL GINGIVA.5) NORMAL MICROSCOPIC FEATURES

A. GINGIVA EPITHELIUM ORAL EPITHELIUM SULCULAR EPITHELIUM JUNCTIONAL EPITHELIUM. B. GINGIVAL CONNECTIVE TISSUE

GINGIVAL COLLAGEN FIBERS CONNECTIVE TISSUE CELLUR COMPARTMENT BLOOD SUPPLY, LYMPHATICS AND NERVES.6) FUNCTIONS OF GINGIVA 7) AGE CHANGES IN GINGIVA8) CORRELATION OF NORMAL AND CLINICAL

MICROSCOPIC FEATURES 9) CLINICAL CONSIDERATIONS10) SUMMARY AND CONCLUSION11) REFERENCES.

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1) INTRODUCTION

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. Therefore

some times it is referred to as the marginal periodontium. Periodontium is the

functional unit of tissue supporting the tooth. The tooth and periodontium together

are called the Dentoperiodontal unit. The tissues of the periodontium include the

gingiva, the periodontal ligament, and the cementum and alveolar process. They

are biologically interdependent. According to the ‘Dorland medical Dictionary’

the word Gingiva means the ‘gums of the mouth’. It is that part of the oral mucosa

overlying the crowns of unerrupted teeth and encircling the necks of those that

have erupted, serving as the supporting structure for sub adjacent tissues. The oral

mucosa is classified into three different types.

1) Masticatory mucosa: Gingival and the covering of hard palate.

2) Specialized mucosa: Dorsum surface of tongue.

3) Lining mucosa: The remainder of the oral mucous membrane.

2) DEFINITIONS:-

CARRANZA:- Gingiva is the part of oral mucosa that covers the alveolar

processes of jaws and surrounds the neck of teeth

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.

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GRANT:- Gingiva is the part of oral mucous membrane attached to the teeth and

the alveolar processes.

GENCO:- Gingiva is that part of oral mucous membrane that covers the alveolar

processes of the cervical portions of the teeth.

LINDHE:- Gingiva is that part of masticatory mucosa covering the alveolar

processes of the cervical portions of teeth.

3) DEVELOPMENT OF GINGIVA

The gingival develops as a coalescence of oral and enamel organ

epithelia, as the tooth emerges into the oral cavity, the reduced enamel organ

epithelium covering the surface of the tooth fuses with the oral epithelium,

with further tooth eruption. The reduced enamel epithelium separates from the

primary cuticle on the surface of the enamel. The resulting cuff of epithelium

and connective tissue surrounding the neck of the tooth becomes the gingiva.

The reduced enamel organ epithelium continues its apical separation along the

enamel surface until the tooth reaches occlusion. At that point, the gingiva

covers only the cervical portion of the crown. Thereafter, the epithelium

attachment is limited to a zone at the Cemento Enamel junction.

Unlike three other tissues of the periodontium i.e. cementum,

alveolar bone and periodontal ligament, the gingiva does not derive from the

mesenchymal dental follicle proper. It is a derivative of the stomodeal

ectoderm and mesoderm.

4) NORMAL CLINICAL FEATURES.

Anatomically, Gingiva has been divides into.

(A) MARGINAL GINGIVA.

(B) ATTACHED GINGIVA

(C) INTERDENTAL GINGIVA.

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(A) MARGINAL GINGIVA / FREE GINGIVA / MARGO GINGIVALIS /

UNATTACHED GINGIVA.

DEFINITION: 1) It is the terminal edge or border of the gingiva surrounding the

teeth like a collar.

2) In about 50% of cases, it is demarcated from the adjacent attached

gingiva by a shallow linear depression- The free gingiva groove.

3) The marginal gingiva is usually 1mm wide and it forms the soft

tissue wall of the gingival sulcus.

4) It can be separated from the surface with a periodontal probe.

Defined by four Boundaries:

1. Coronally: by gingival margin

2. Apically: by free gingival groove

3. Inner margin: by gingival sulcus

4. Outer surface by vestibular or oral cavity.

In absence of this free gingival groove, the apical boundary would correspond to a

line opposite the bottom of the gingival sulcus, which is usually about 1.0 to

1.5mm apical to the free gingival margin. The free gingival groove Histological

appearance as v-shaped notch at a heavy epithelial ridge. The free gingival groove

develops at the level of or somewhat apical to, the bottom of the gingival sulcus.

GINGIVAL SULCUS:

DEFINITION: Is the shallow crevice or space around the tooth bounded by the

surface of the tooth on one side and the epithelial lining the free margin of the

gingiva on the other. It is V-shaped and barely permits the entrance of a

periodontal probe. Under absolutely normal / ideal conditions, the depth of

gingival sulcus is 0 are about 0. In clinically health gingiva in humans, Histologic

depth 1.8mm with variations from 0-6mm. Probing depth 2-3mm.

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GINGIVAL FLUID: The gingival sulcus contains a fluid that seeps into it from

the gingival connective tissue through the thin sulcular epithelium.

FUNCTIONS OF GCF:

1) Cleanses material from the sulcus.

2) It contains plasma proteins that may improve adhesion of the epithelium to

the tooth.

3) It possesses antimicrobial properties.

4) It exerts antibody activity in defense of the gingiva.

ATTACHED GINGIVA:

The attached gingiva is continuous with the marginal gingiva. It is firm,

resilient. and tightly bound to the underlying periosteum of the alveolar bone. The

attached gingiva lies between the free gingival mucosa and alveolar mucosa. It is

separated from the former by the free gingival groove and from the latter by the

mucogingival junction.

WIDTH OF ATTACHED GINGIVA:

It is defined as the distance between the mucogingival Junction and the

projection on the external surface of the bottom of the gingival sulcus or the

periodontal pocket. It should not be confused with the width of keratinized

gingiva, because the keratinized gingiva includes marginal gingiva. The width of

the attached gingiva is determined by subtracting the depth of the sulcus / pocket

from the distance of the crest of margin to the mucogingival Junction.

It is also determined by.

1) Schillers potassium Iodide solution.

2) Pushing the alveolar mucosa coronally with a blunt instrument.

The width of attached gingiva on the facial aspect differs in different areas of the

mouth. It greatest in the Incisor region, 3.5 to 4.5mm in the maxilla, 3.3 to 3.9mm

in the mandible Less in the posterior segments. Least width in the 1st premolar

area 1.9mm in maxilla and 1.8 mm in the mandible.

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There are 3 micro gingival lines.

1) Facial Maxillary 2) Facial Mandibular 3) Lingual mandibular

Lingual maxillary is not seen as there is no alveolar mucosa on the palate and

palatal tissue is firmly attached to the bone. Lingual mandible, the attached

gingiva terminates at the junctional with lingual alveolar mucosa which is

continuous with the mucosa membrane lining the floor of the mouth.

Width of attached gingiva increased with

1) Age

2) Supraerupted teeth.

Width of attached gingiva decreased with

1) Base of the pocket is apical / close to muco gingival line.

2) High Frenum attachment.

3) Gingival recession. In Type II, III, IV.

Importance of attached gingiva.

1) Act as a mechanical barrier.

2) Resistance to functional stress.

3) Act as buffer between movable marginal gingiva and immovable alveolar

mucosa.

Adequacy of attached gingiva can be determined by Tension test. Consists of

retracting the checks and lips laterally with fingers and checking if such tension

pulls the marginal gingiva from the teeth. This reduced width of attached gingiva

can be corrected by mucogingival surgery.

The attached gingiva is characterized by a surface that appears stippled

portion at the epithelium appears to be elevated, and between the elevations there

are shallow depressions, the net result of which is stippling. The depression

corresponds to the center of heavier epithelial ridges. These are due to functional

adaptations to mechanical impacts. The disadvantage of stippling is an indication

of edema i.e. progressing gingivitis. In younger females stippling is more

prominent than males, due to finely textured connective tissue However with

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increasing age the collagenous fiber bundles become coarser in both sexes. Males

tend to have more heavily stippled gingival than females. Oral epithelium shows

another sex differentiation in females the majority of the nuclei contain a large

chromatin particle adjacent to the nuclear membrane.

INTERDENTAL PAPILLA:-

Is that part of the gingiva that fills the space between two adjacent

teeth. When viewed from the oral or vestibular aspect, the surface of the Inter

dental papilla is triangular, in a three dimensional view the Inter dental papilla of

the posterior teeth is tent shaped, where as it is pyramidal between the anterior

teeth. When the Inter dental papilla is tent shaped the oral and vestibular corners

are high, where as central part is like a valley. The central concave area fits below

the contact point, and this depressed part of the Inter dental papilla is called col.

Col refers to a pass between adjacent peaks of a mountain. Col is the shelter

reservoir for entrapped food. When gingiva is inflamed and hyperemic, the Col is

exaggerated. The Col usually exhibits signs of inflammation, because it is difficult

to keep the Inter proximal area clean because of plaque and calculus form there,

with the age Col flattens. Col is covered by thin non keratinized epithelium which

is more vulnerable to periodontal disease. If diastema is present the gingiva is

firmly bound over the Inter dental bone and forms a smooth rounded surface with

out inter dental papilla.

Gingival epithelium

Functions: The main function is 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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Cells of the epithelium:

The principal cell type of Gingival epithelium as well as have other stratified

squamous epithelia is the keratinocyte. Other cells are the clear cells on Non

keratinocytes

Keratinocytes: content of epithelial cell is keratin, hence keratinocytes synthesize

keratin and constitute about 90% of the gingival epithelium.

Fine structure of the epithelial cell:

Tonofilaments :

They are fibrous proteins synthesized by the ribosome’s and are seen as long

filament with a diameter of approximately m. They belong to class of

intermediate filaments and form cytoskeleton of keratin proteins when they

become aggregated to form bundles of filaments, they are called as Tonofibrills.

Junctions between the cells of the epithelium

The epithelium functions as a barrier due to the close contact (or) cohesiveness of

the epithelial cells. This cohesion between cells is provided by viscous

intercellular material consisting of protein carbohydrate complexes provided by

the epithelial cells. In addition to these, there are specialized in addition to thee,

there are specialized structures which provide the connection between the cells /

keratinocyte these are.

I) Desmosmes: Consists of 2 dense attachment plaques one from each cell

separated by interval of m wide that contains three dense lamellae. Bundles of

tonofilaments insert into the attachment plaques and these loop in and out of the

attachment plaque without crossing into the adjacent cells. In a desmosome, the

membranes come so close together, their glycoprotein rich surface coats (or) the

plaque touch forming an intermediate electron dense line in the extra cellular

compartment. If epithelial cells shrink during histologic processing, desmosomes

usually remain intact and so appear as inter cellular bridges.

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structure of desmosome:

Desmosomes considered as 2 hemidesmosomes facing one another. Desmosome

consists of 2 adjoining hemidesmosomes, separated by a zone containing electron

dense granulated material. In addition, desmosome consists of.

1) Outer leaf let(OL) of cell membranes of two adjoining cells

2) Thick, inner leaf let (IL) of the cell membranes.

3) The attachment plaque (AP) which represent granular and fibrillar material

in cytoplasm.

Desmoplakin : is a protein, forms the attachment plaque of desmosome but not of

hemidesmosome.

Hemidesmosome: consists of a single attachment plaque present between a cell

and a non cellular surface (only one cell membrane is present). Its glyco protein

rich coat is compressed to form a dense line midway in the space between the cell

and non cellular surface.

Eg. Adhesion between the epithelium and connective tissue is provided by

Hemidemosomes present on the basal membranes of the cells of the basal layer.

Tonofilaments are also inserted into attachment plaque of hemidesmosomes.

Functions of the Desmosomes, Hemidesmosomes and Tonofilments.

These structures together represent a mechanical linkage that distribute and

dissipates localized forces that are applied on the epithelial surface over a wide

area

II Tight junctions: (Zona occludens) Rarely seen. Adjacent membranes are so

tightly apposed that there is no intercellular space and appear to be fused.

III Gap junctions: is a region, where adjacent cell membranes run closely

together, separated by only a small gap. These Junctions may allow electrical /

chemical communication between the cells.

Basal lamina:- 300 to 400 A0 Thick

(1) Lamina Lucida.

(2) Lamina Densa.

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Lamina Lucida: Clear zone about m wide, adjacent to the epithelial cell

membrane called the lamina Lucida, to which hemidesmosomes are attached.

Contents:1) Glycoproteins i.e. laminin. 2) Bullous pemphigoid antigen.

Lamina Densa: Fine granular (or) filamentous material m, thick called the

lamina Densa. Separated from the epithelial cell membrane by the lamina Lucida.

-Anchoring fibrils: (Zona Reticularis) from lamina Densa small loops of

finely banded fibrils are inserted called as anchoring fibrils are composed of VII

collagen.

-Collagen fibrils: Run through these loops of anchoring fibrils and are thus

interlocked with the lamina Densa to form a flexible attachment. Type I and II.

-Type IV Collagen is present in L. Densa. Bio chemically lamina Densa

arranged in a “chicken wire” configuration. It is now believed that all the basal

lamina except the anchoring fibrils is synthesized by the epithelium.

Keratinization

The oral epithelium maintains its structural integrity by a system of continuous

cell renewal and involves the two processes of proliferation and differentiation.

Thus, the cells of the epithelium can be considered to be of two functional

populations.

1) A Progenitor population:- Whose function is to provide new cells.

2) A Maturating population:-Whose cells are undergoing a continuous process

of differentiation and maturation to form a protective surface layer.

Epithelial proliferation:

The progenitor cells are situated mainly in the basal layer. Recent studies have

shown that the progenitor compartment is not homogeneous, but consists of two

functionally distinct subpopulation of cells.

A. A small population of stem cells whose function is to produce basal

cells and thus retain the proliferative potential of the tissue.

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B. A large population of Amplifying cells whose function is to increase

the number of cells available for subsequent maturation. Regardless

of the cell type, either stem (or) amplifying cells, cell division is a

cyclic activity and is divided into 4 phases.

1) (S) Synthetic phase: During this phase, cells which are preparing to divide

initially, double their DNA content.

2) G3 Phase :– Represents a short rest period.

3) (M) Mitotic phase:- (Only histologically distinguishable phase) which is

subdivided into stages of

- Prophase

- Metaphase

- Anaphase

- Telophase

Cells enter these phases of mitosis to produce two daughter cells.

After the cell division, each daughter cell makes the decision either to recycle in

the progenitor population (or) to enter the maturating compartment. This decision

making period is known as 4 Dichophase(D) on an average, one daughter cell

enters the maturation compartment and other enter post mitotic pre synthetic

period G1.

The time necessary to replace all the cells in the epithelium is known as the

turnover time of epithelium, Turn over time for gingiva has been estimated to be

41-57 days (rate of cell proliferation).

Epithelial Proliferation / differentiation.

Daughter cells that have arisen from the cell division in the basal layers, either

recycle (or) undergo a process of maturation as they move to the surface

maturation / differentiation involves the processes of keratinization, which is

defined as a process that consists of a sequence of biochemical and morphologic

events that occur in the cell, as it migrates from the basal layer to the surface.

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The main morphologic changes seen are.

1) Progressive flattening of the cell.

2) Increasing prevalence of tonofilaments and inter cellular junctions.

3) Production of keratohyalin granules.

4) Disappearance of the nucleus.

Functions of keratinization:-

Formation of a protective surface layer, the formation of a surface layer of keratin

makes the epithelial surface of the masticatory mucosa and regions of specialized

mucosa inflexible, tough and resistant to abrasion.

Histologically the keratinized epithelium shows a number of distinct layers of

strata.

THE KERATINIZING ORAL EPITHELIUM HAS FOUR CELL LAYERS.

1) STRATUM BASALE

2) STRATUM SPINOSUM

3) STRATUM GRANULOSUM

4) STRATUM CORNEUM.

1) STRATUM BASALE or proliferate layer.

The cells of stratum basale are cuboidal (or) low columnar, in shape with

protoplasmic processes located immediately suprajecent to the basement

membrane. These cells made up of cells that synthesize DNA and undergo mitosis,

thus providing new cells. Sometimes mitotic figures are seen in stratum spinosum

there fore basal cells and Para basal spinous cells and called Stratum

Germinativum. Basel cells are of two types.

1) Serrated and heavily packed with tonofillaments. (Adaptation for

attachment).

2) Non- serrated slow cycling stem cells.

Specialized cells called hemidesmosomes, which adapt the basal lamina, are found

on basal surface. They attach the epithelium to connective tissue. The basal lamina

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is made up of a clear zone. The lamina Lucida just below epithelial cells and a

dark zone. The lamina dense beyond the lamina Lucida and adjacent to connective

tissue. Below basal lamina is a fibrillar zone that is not of epithelial origin. The

lateral borders of adjacent basal cells are closely apposed and connected by

desmosomes.

2) STRATUM SPINOSUM or prickle cell layer:-

Located above basal cell layer. These cells appear to possess spinous

or spiky process, hence the name “spinosum”. The process is due to cell shrinkage

during histologic processing. The spinous cells are irregular polyhedral and larger

than basal cells. The cells are joined by intercellular bridges which are

desmosomes and tonofibrils are bundles of tonofilaments of the four layers

spinous layer is the most active in protein synthesis. The two layers stratum basale

and stratum spinosum account for one third to two third of total epithelial

thickness.

3) STRATUM GRANULOSUM:-

Contains flatter and wider cells. These cells are larger than the spinous cells.

This layer is so named because of basophilic keratohyalin granules that it contains,

these granules are dense and relatively large 0.5to1um, these are present in

cytoplasm. The keratohyalin Granules are believed to function in the process of

keratinization. The cell of this layer is of 3-5 cells thick. Odoland body or

keratinosome membrane forms in the upper spinous and granular cell layers.

4) STRATUM CORNEUM

Also called the cornified layer it consists of flattened

eosinophilic cells. The cells of the stratum corneum are flat, devoid of nuclei and

full of keratin filament surrounded by a matrix. The junction between the

nucleated cells in the stratum granulosum and stratum corneum is quite abrupt.

This layer is characterized by almost exclusive presence of tonofibrils in the

cytoplasm. The outermost cells of this zone are shed during the process of

exfoliation.

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Three types of keratinization are seen.

Ortho keratinization Para- keratinization Non keratinization

A) Complete A) partial / incomplete A) No

Keratinization Keratinization Keratinization

B) No nuclei in B) Pyknotic nuclei B) Viable nuclei

Stratum corneum in stratum corneum. present in all

Superficial cells

C) Well defined stratum C) No stratum granulosum C) No S. corneum/

granulosum keratohyaline granules granulosum.

D) Example:-outer D) Ex: - most areas of D) Ex:-Sulcular &

gingival epithelium. gingival epithelium junctional epithelium

.

The gingiva is 75% parakeratinized.

15% keratinized.

10% Non Keratinized.

KERATINIZED EPITHELIUM NONKERATINIZED EPITHELIUM

Cell layer major features cell layers major features

Basal Basal

Cuboidal / columnar cells Cuboidal / columnar of cells

containing bundles of containing separate

tonofibrils and other tonofilament and other cell

cell organelles; organelles.

Site of majority of cell site of majority of cell

divisions. divisions.

Spinous Layer Prickle Cell

Larger ovoid cell containing larger ovoid cell containing

conspicuous tonofibril dispersed tonofilament

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bundles; membrane membrane coating

coating granules appear granules appear in upper

In upper part of this layer part of layer and filament

become numerous.

Granular Intermediate

Flattened cell containing slightly flattened

conspicuous keratohyaline cell containing

granules associated with tonofibrils. numerous dispersed

membrane coating granules tonofilaments and

fuse with cell membrane in glycogen

upper part; there is also

internal membrane thickening

Keratinized Superficial

Extremely flattened and slightly flattened cells with dispersed

dehydrated cells in which fragmented glycogen; fewer organelles

all organelles have been lost; present but nuclei persist to the surface.

cells .

Keratinization:-

The basal cells posses the ability to undergo cell division. Therefore, it is in

the basal layer that the epithelium is renewed and so, this layer called Stratum

Germinativum. When two daughter cells have been formed by cell division, an

adjacent older basal cell (OB) is pushed into the spinous layer and starts as a

keratinocyte to transverse the epithelium, it takes approximately one month for a

keratinocyte to reach the stratum corneum, from where it is desquamated under

normal circumstances, there is complete equilibrium between the cell renewal and

desquamation. As the basal cell migrates through the epithelium, it becomes

flattened and has its long axis parallel to the tissue surface. The keratinocyte

undergo continuous differentiation and specialization. From the basal layer to the

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granular layer, both the number of tonofilaments in the cytoplasm and the number

of desmosomes increase. In contrast, the number of organelles such as

mitochondria, lamellae of rough endoplasmic reticulum and Golgi complexes

decrease in the keratinocyte as they reach the surface. In the Stratum Granulosam,

electron dense keratohyalin granules and clusters of glycogen containing granules

start to occur such granula are believed to be related to the synthesis of keratin.

Thus, once the keratinocyte has left the basement membrane, it can no longer

divide but maintain a capacity for production of proteins (Tonofilments and

keratohyalin granules). In the granular layer, the keratinocyte is deprived of its

energy and protein producing apparatus (probably by enzymatic break down) and

is abruptly converted into a keratin filled cell, which from the stratum corneum is

shed from the tissue surface.

Main events occurring in the maturation ( keratinized epithelium).

As keratinization progresses, basal cells initially synthesize low molecular weight

keratin proteins (such as K19, 40kd) and later express other higher molecular

weight proteins, as they migrate to the surface, main component of stratum

corneum is keratin 68kd (k1).

1. Other proteins are also synthesized during the maturation process keratolinin

and involucrin which form a chemically resistant structure called the envelope

located below the cell membrane. Now as the cells of the granular layer reach the

Junction of Stratum Corneum (or) keratinized layer, all the organelles including

the nuclei and the keratohyaline granules disappear. Keratohyaline granules are

irregular in shape, about m in diameter, and probably synthesized by the

ribosome’s. On reaching the corneum layer, these granules disappear and give rise

to a protein called fillagrin, which forms the matrix of the corneocytes. Thus, in a

fully differentiated state corneocytes are mainly formed by bundles of keratin

tonofilaments embedded in an amorphous matrix of fillagrin surrounded by a

envelope under the cell membrane (formed by keratolinin and involucrin).

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2. The organelles disappear as they reach the surface. This disappearance is

brought about by Keratinosomes \ Odland bodies. Which are modified lysosomes,

located in the uppermost cells of the stratum spinosum. They secrete acid

phosphatase, an enzyme involved in the destruction of organelle membrane.

3. Enzymes of the pentose shunt (alternative pathway of glycolysis) increase their

activity towards the surface. As a result, there is more RNA formed (due to

breakdown) and thus more synthesis of keratinization proteins).

As a result of these factors, cells of the keratinized layer are dehydrated, flattened

and resistant to mechanical damage and chemical solvents. In 3-D, they have the

form of hexagonal discs, called squame. These are lost by desquamation and

replaced back by the underlying cells. The degree of gingival keratinization

diminishes with age and onset of menopause. Most keratinized areas in decreasing

order – palate, gingiva, tongue and cheek

Control of epithelial proliferation and maturation

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 maturating epithelial cells called chalones.

Chalones act by negative feed back mechanism. The slower the rate of

maturation, the lower the local chalone concentration and greater the mitotic

activity.

Non keratinocytes:

1.Melanocytes.

The color of the mucosa is the net result of number of factors. One of

which is pigmentation which is endogenous and exogenous. The endogenous

pigmentation is most commonly contributed by melanin. Melanin is produced by

melanocytes. These are situated in the basal layer of the oral epithelium.

Melanocytes are derived embryo logically from the neural crest ectoderm and

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migrate to the basal aspect of epithelium of the 2nd week of gestation. There they

divide and maintain themselves as self reproducing population of cells.

Melanocytes are astral shaped cells and are characterized by presence of long

cellular process known as dendritic processes these cytoplasmic extension pass

between the adjacent keratinocytes, often passing through several layer of cells.

These cells do not contain desmosomes and tonofilaments. However, they do

contain an extensive Golgi zone and a well developed rough endoplasmic

reticulum. Melanin is synthesized with in melanocytes and stored in oval shaped

small structure known as melanosomes.(Melanin synthesis begin in the

endoplasmic reticulum]. Tyrosinase Synthesized in ribosome’s passed via

Endoplasmic reticulum to Golgi system. In Golgi system it accumulates in

vesicles, Vesicle develops to form Helical protein fibrils Called Pre melanosome

(Tyrosinase).Oxidizes to form DOPA (3-4-Dihydroxy phenol – L – alanine.

Polymerizes into Pigment melanin. Melanosomes are melanin containing granules

approx 0.1 to 0.m in size. The function of melanocytes is not known. All

individual possess same number of melanocytes regardless of color of skin (or)

oral mucosa. Difference in pigmentation is primarily the result of the activity of

the melanocytes and the enzymatic processes there in and the rate at which the

melanosomes are breakdown in keratinocytes. In persons with heavy melanin

pigment cells containing melanin may be seen in the connective tissue (probably

macrophages have taken up these melanosomes- these cells are referred to as

melanophages ). Regardless of the activity of the melanocytes, there are

approximately 7-9 melanocytes for every 100 basal cells (or) about 1660

melanocytes / mm2 of outer epithelium surface.

Langerhan’s Cell:

Like the melanocytes, the langerhan’s cell is a dendritic cell, usually seen

in the supra basal layer, often in the Stratum Spinosum. The dendritic processes

extend throughout Stratum Spinosum. This cells lack desmosomal attachments to

surrounding cells and no tonofilaments. The langerhan’s cell is characterized by

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the presence of small rod (or) flask shaped granules sometimes called the

“Birbeck” granule (or) also called tennis racket organelles in cytoplasm. These

arise from pynocytotic vesicle i.e. from sac like invagination of the plasma

membrane. The langerhan’s cell contains well developed golgi bodies, rough

endoplasmic reticulum and numerous vacuoles. The nucleus is multiply notched,

thus has irregular contour. The langerhan’s cell derived from bone marrow and is

equivalent to modified monocytes and migrates to the epithelium. They move in

and out of the epithelium. This is an evidence suggesting that they have an

immunologic function. These recognize and posses antigenic material that enter

the epithelium from the external environment and presents it to helper T-

Lymphocytes. It is also likely that langerhans cells can migrate from epithelium to

regional lymph nodes. Thus they play a role in immune mediated reaction of oral

mucosa. In the oral gingival epithelium there are on an average of 160 langerhan’s

cells every Sq.mm of epithelium surface. Function: Langerhan’s cells are antigen

presenting cells. They engulf antigens from the external environment, and the

intracellular lysosomes split the antigens into peptide components. These

fragment’s are then transferred to T-lymphocytes which are important cells in the

immune system.

Merkel’s Cells:

Merkel cells are located in the basal cell layer of the gingival epithelium and

appear individually (or) in clusters. These cells appear similar to keratinocytes

possessing tonofilaments and desmosomes. These are not dendritic cells. The

characteristic feature of Merkel cell is presence of small spherical membrane

bound vesicle in the cytoplasm. This spherical mass filled with dark osmiophilic

substance / granular. These vesicles are situated adjacent to nerve fiber and these

granules may liberate a neuro - transmitter substance across the synapse like

Junction between the Merkel cell and nerve fiber and their trigger an impulse. This

arrangement resemble with neuro physiologic evidence suggest that Merkel’s cells

are sensory and respond to touch and pressure.

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Lymphocytes:

Lymphocytes found in gingival epithelium are associated with an inflammatory

process. They may be found anywhere in the gingival epithelium but most often

are in the area of junctional epithelium.

Leucocytes:

Leucocytes are found in the gingival epithelium. Usually in the sulcular and

attached epithelium. These cells move between the epithelial cells and through its

surface and become salivary corpuscles. They contribute protein and

immunochemical substances to the sulcular fluid.

Keratinisation A genetic phenomenon:-

It has been suggested that the presence of keratinized epithelium on the

masticatory mucosa is a functional adaptation to the mechanical irritation caused

by mastication. To prove this assumption wrong, a very interesting research

experiment was carried out. In a monkey, the gingival (G) and the alveolar mucosa

(AM) were transposed surgically. The gingival which is keratinized was

positioned in the area of the alveolar mucosa which is non keratinized and the

alveolar mucosa was placed in close contact with the teeth.

After 4 months, it was seen that the transplanted gingival had retained its

characteristics, morphological features of a masticatory mucosa, that is, it

exhibited a distinct surface layer of keratin along with the epithelium connective

tissue interface (i.e. rete pigs and connective tissue papillae). This observation

showed that the characteristic of the gingiva was genetically determined rather

than an adaptation to environmental stimuli. However, a narrow Zone of a new

keratinized gingiva (NG) has regenerated between the transplanted alveolar

mucosa and the teeth, there by pushing the alveolar mucosa to become interposed

between the transplanted and the newly formed gingiva. The connective tissue of

the new gingival has regenerated from the connective tissue of the supra alveolar

and PDL compartments.

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The epithelial cells covering the transplanted alveolar mucosa, which is

non keratinized, had migrated to the newly formed gingival connective tissue.

However, the epithelium covering the new gingiva was found to be keratinized.

This implicated that the newly formed gingival connective tissue possessed the

ability to induce differentiation of the epithelium, which was derived from the non

keratinized, transplanted alveolar mucosa. Thus, we can see that the specificity of

the gingival epithelium is determined by genetical factors inherent in the

connective tissue.

I. The oral / outer epithelium:

Covers the crest and outer surface of the marginal gingiva and the surface of the

attached gingiva. It is keratinized / parakeratinized (or) present as various

combination of these surfaces. The prevalent surface however is parakeratinized.

In orthokeratinized areas Keratins K1, K2, K10, and K12.Which are specific for

epidermal differentiation, are expressed with high intensity K6, K16 characteristics

of highly proliferate epithelium.

In parakeratinized areas Keratins K1, K2, K110, and K12. Which are

expressed with low intensity. These areas also express K19, which is usually absent

from ortho keratinized area.

II. The sulcular epithelium:

Lines the gingival sulcus. It is thin, non keratinized, stratified squamous

epithelium without rete pegs, which extends from the coronal limit of the

junctional epithelium to the crest of the gingival margin. It usually shows

numerous cells with hydropic degeneration. It contains keratin K4 , K13 and K19. It

lacks stratum granulosum and corneum. cytokeratins K1 K2 K10, and K12. Lacks

merkel cells.

The sulcular epithelium has the potential to keratinize, if:

1) It is reflected and exposed to the oral cavity,

2) The bacteria flora of the sulcus is totally eliminated.

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These findings suggest that the local irritation of the sulcus (because of its contact

with tooth) prevents sulcular keratinization.

Functions of sulcular epithelium. It may act as a semi permeable membrane

through which injurious bacterial products pass into the gingiva and through

which tissue fluid from the gingival seeps into the sulcus.

III. The junctional epithelium: (j.e)

The junctional epithelium consists of a collar- like band of stratified

squamous non-keratinizing epithelium that joins gingival connective tissue to the

tooth surface.

1. It is 3-4 layers thick in early life, but the number of layers increases with age 10

to 20.

2. The length of the junctional epithelium ranges from 0.25 to 1.35mm

3. It is widest in its coronal portion about 15-20 cell layers but becomes thinner

towards the CEJ

4. Cell layers not juxtaposed to the tooth, exhibit numerous free ribosomes’, golgi

complexes lysosome like bodies, cytoplasmic vacuoles and PMN’s and

leukocytes.

5. The J.E expresses K19 (with is absent for keratinized epithelium) and

stratification with specific cytokeratins K5 and K14.

Histologic features:

Like the oral epithelium, the junctional epithelium is continuous self-renewal

structure and is continuously renewed through cell division occurring in the basal

layer. The cells migrate to the base of gingival sulcus from where they are shed.

Cells are arranged in 2 Strata: Basal and suprabasal. The basal and suprabasal cells

are flattened with their long axis parallel to the tooth surface. Three zones have

been identified in the junctional epithelium (Sagle et al, 1979).

(A) Apical shows cells with germinative characteristics,

(B) Middle zone of major adhesiveness,

(C) Coronal zone of greater permeability.

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. Differences between

Junctional epithelium Oral epithelium

The size of the cells relative to the tissue volume is larger

Is smaller

The intercellular space relative to the tissue volume is layer

Smaller

The number of desmosomes is more

Less

Epithelium retepegs and connective tissue papilla are lacking at the junctional epithelium contiss interface

Present

Non-keratinised Keratinised / parakeratinised

Attachment of junctional epithelium to the tooth surface and connective

tissue:-

The junctional epithelium is attached to the tooth surface epithelial

attachment by means of an internal basal lamina which consists of Lamina Lucida

and Lamina Densa (which is adjacent to the enamel). To the L. Densa,

hemidesmosomes are attached and organic strands from the enamel appear to

extend into the lamina densa. The junctional epithelium attaches to the gingival

connective by means of an external basal lamina which has the same structure as

described before.

Functions:

1. It must be noted that unlike the epithelium, connective tissue interface the

lamina densa of the internal basal lamina (facing the enamel) has no anchoring

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fibrils attached to it, which means that the junctional epithelium attaches to it,

which means that the junctional epithelium is physically attached to the tooth via

hemidesmosomes (Schroereder and Listgarten). The junctional epithelium attaches

to afibrillar cementum when it is present on the crown usually restricted to 1mm of

CEJ and the root cementum in a similar manner.

2. The attachment of the junctional epithelium to the tooth is further reinforced by

the gingival fibers, which brace the marginal gingival against the tooth surface.

For this reason, the junctional epithelium and of the gingival fibers are considered

to be a functional unit, refer to as Dentogingival unit.

3. Data has shown that the basal lamina of the junction of epithelial cells

resembles that of endothelial and epithelial cells in its laminin content, but

junctional epithelium differs in its internal basal lamina, which has no type IV

Collagen. These findings indicate that the cells of the junctional epithelium are

involved in the production of laminin and play a key role in the adhesion

mechanism.

4) They contribute to the defense of the gingiva by the continuous migration of

PMN’s through the junctional epithelium.

Gingival Connective tissue:

The connective tissue of the gingiva is known as the lamina propria

(L.P).Lamina propria lies immediately below the epithelium. Consists of 2 layers

A: Papillary Layer: which lies to the subjacent epithelium and consists of

papillary projections between the epithelial retepegs.

B: Reticular Layer: which is contiguous with the periosteum of the alveolar

bone.

The papillary body comprises a variable dense area of connective tissue

papillae ranging from 50-200/mm 2, the epithelium is thrown to form ridges into

which the papilla are interlocked. This interlocking (1) increases the area of

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contact between the epithelium and L.P (2) facilitates exchange of materials to the

epithelium and blood vessels.

Composition:

1) Cells – 5% (mainly fibroblast)

2) Fibers- 60% (mainly collagen)

3) Vessels, nerves and matrix – 35%

Cells:- 1)Fibroblasts, 2)Mast cells, 3)Small number of PMN’s for host defense,

4)Macrophages, 5)Monocytes,6)Lymphocyte,7)Plasma cells,8)Endothelial cells,

9)Histocytes

1) Fibroblast – 65% of total cell population,

- Morphologic characteristics. Stellate (or) elongated with

abundant

rough endoplasmic reticulum.

- Distribution: Through out L.P

- Functions: secretion of fibers and around substance:

a) Fibroblast: Synthesize collagen and elastic fibers.

b) They synthesized Glycoproteins and Glycosamino glycons

c) They regulate collagen degradation.

Fibres:

The connective tissue fibres are produced by the fibroblast and can be divided

into.

1) Collagen fibres

2) Reticulin fibres

3) Oxytalan fibres

4) Elastic fibres.

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Collagen fibres: (60% of connective tissue volume). The smallest unit of the

collagen molecule is known as the Tropocollagen and is synthesized with in the

fibroblast. It consists of 3 helical polypeptide chains interwined to form a helix

and each chain consisting of about 1000 amino acids (1/3rd glycine, 20% proline

and Hydroxy proline). After the synthesis of tropocollagen molecule it is secreted

out from the fibroblast into the extra cellular space. First the tropocollagen

molecules are aggregated longitudinally to form protofibrils. These are then

laterally aggregated in parallel to form collagen fibrils with an overlapping of

tropocollagen molecule by about 25% of their length. The collagen fibres are

bundles of collagen fibrils, aligned in such a way that fibres exhibit a cross

banding with a periodicity of approximately of 700A0. As the collagen fibres

mature, covalent cross-links are formed between the tropocollagen molecules

resulting in reduction in collagen solubility. Cementoblast and osteoblasts also

possess the ability to produce collagen.

Collagen

Type I - Forms the bulk lamina propria (91%)

Type III - For Tensile strength (8%)

Type V - Less than (1%).

Functions of gingival collagen fibres;

1) To brace the marginal gingival firmly against the tooth.

2) To provide the rigidity necessary to with stand the forces of mastication without

being

deflected from the tooth surface.

3) To unite the free marginal gingival with the cementum of root and the adjacent

attached gingiva.

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Gingival fibres are divided into following groups (Grants)

Principal group fibres Secondary group

1) Dento gingival, 1) Transgingival,

2) Dento periosteal, 2) Inter gingival,

3) Alveolo gingival, 3) Inter papillary,

4) Circular, 4) Semi circular,

5) Transseptal group. 5) Periosteal – gingival,

6) Inter circular.

Carranza (1996) has classified gingival fibres into

1) Gingivo dental

2) Circular

3) Transeptal

4) Semicircular

5) Transgingival fibres.

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PRINCIPLE GROUP FIBERS ARE:

Origin Insertion Function

1. alveolar gingival Periosteum of

alveolar crest

Lamina

propria

Attaching the gingiva to the

alveolar bone.

2. Dento gingival Cementum Lamina

propria

Support to the gingiva by

attaching it to the tooth

3. Dento periosteal Cementum (CEJ) Periosteum of

alveolar crest

These fibres help to anchor

tooth to bone and protect

the

periodontal ligament.

4. Circular Encircle each

tooth in the zone

of marginal

gingiva and

attached gingiva

Help to maintain the

contour and position of the

free gingiva holding it firm

against the tooth.

5. Transeptal fibers Cementum of one

tooth to the

cementum of

neighboring tooth,

in the inter-

proximal areas

coronal to the

alveolar crest.

They protect inter proximal

bone and maintain the tooth

to tooth contact.

Page 30: GINGIVA 1 / orthodontic courses by Indian dental academy

Secondary Group fibres are

Origin Insertion Function

A. Periosteal- gingival

Fibers.

Periosteum of the

alveolar process

Attached

gingiva

Attached the

gingiva to the

alveolar bone.

B.Interpapillary fibers. Extending facio- lingual

direction in the inter-

dental gingiva.

Vestibular and

oral gingival

papilla.

Provide support

to gingival

papilla.

C.Transgingival fibers. Are arranged between

and around the teeth with

in the attached gingiva.

Attached

gingiva.

The alignment of

teeth in the arch.

D. Intercircular fibers. Arisefrom the cementum

on distal surface of a

tooth extending buccally

and lingually around

adjacent tooth.

Inserted

mesial surface

of the root of

next tooth.

Help to stabilize

teeth in the arch.

E. Inter gingival fibers Are arranged with in

attached gingiva in mesio

distal direction just

beneath the basement

membrane.

Attached

gingiva.

Provide support

and contour to

the attached

gingiva.

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F. Semicircular Extend from mesial

surface of the tooth

distally and get inserted

to the distal surface of

the same tooth forming a

half circle around each

tooth.

Inserted on the

opposite side

of the same

tooth.

These fibers are

almost at the

same level as

circular fibers &

help to support

the free margins

of gingiva.

Other fibres seen as gingival connective tissue;

2) Reticulin fibres:- Are present at the epithelium connective tissue and the

endothelium connective tissue interfaces.

3) Oxytalan fibres:- Are present in all connective tissue structures of the

periodontium and are composed of long thin fibrils with a diameter of approximate

150A0 function is yet unknown. In the Periodontal ligament, these fibres run

parallel to the root surface in a vertical direction and bend to attach to cervical 3rd

of cementum. They are thought to regulate vascular flow.

4) Elastic fibres:- Are present in the connective tissue of the gingiva and PDL

only in association with blood vessels. The elastic fibre system is composed of

oxytalan, elanulin and elastic fibres distributed among the collagen fibres

(carranza, 1996).

Matrix:

The matrix constitutes the ‘environmental’ for the cell. It is produced by the

fibroblast with some components being formed by mast cells and other

components are derived from the blood. It composed of protein polysaccharide

macromolecules Proteoglycans and glycoproteins.

1. The Proteoglycans:- contain glycosamino glycans (Chondrotin sulfate,

Hyaluronic acid) polysaccharide component – always predominant in

proteoglycans, polysaccharide components are attached to protein.

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2. The glycoproteins:- Protein component is predominant here, mainly fibronectin

binds fibroblasts to the fibres and to many other component of the intercellular

component.

Glycosaminoglycans:- Are large flexible chains of negatively charged molecules,

each of which occupies a rather large space. In such a space, smallest molecules

(eg, water and electrolytes) can be incorporated, while larger molecules are

prevented from entering. Therefore, the proteoglycans act as a molecular filter and

in addition, play an important role in regulation of cell movement in the tissue.

Due to their structure and hydration, the macromolecular exert resistance towards

deformation and are of importance for the resilience of the gingiva. If gingiva is

suppressed, the macromolecules become deformed when pressure is eliminated

they region their original form.

Blood supply

Maxilllary gingiva sub terminal branches

Anterior. Anterior superior alveolar artery

Lingual Major palatine artery

Buccal Buccal artery

Posterior Posterior superior alveolar artery

Lower gingiva:

Anterior buccal. Mental artery

Anterior Lingual Inclusive and sublingual artery

Posterior Lingual Interior alveolar and sublingual artery

Posterior Buccal Interior alveolar and buccal artery

3 Sources of blood supply to gingiva

1) Supra periosteal arterioles: Along the facial and lingual surfaces of alveolar

bone from which capillaries extend along the sulcular epithelium and

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between the rete pegs of the external gingival surface. Occasional branches

of the arteriolar pas through the alveolar bone to the periodontal ligament or

run over the crest of the alveolar bone.

2) Vessels of the PDL: which extend into the gingiva anastamose with

capillaries in the sulcus area.

3) Arteriolar that emerge from crest of the inter dental septa.

Nerve supply:

Upper gingiva:- Anterior, posterior and middle Superior alveolar branches of

Buccal and lingual maxillary nerve, palatal nerves

Lower gingiva:- Inferior alveolar branch of mandibular nerve, buccal branch of

Buccal and lingual:branch of mandibular nerve sub-lingual branch of lingual

nerve.

Receptors are seen as free endings within the papillary layer of the lamina propria.

- Touch endings (meissner’s corpuscles) and

- Temperature receptors are seen as coiled terminals

- Pain receptors are seen as fine fibres in the papilla.

All are found in and attached gingiva .

The following nerve structures are present in connective tissue.

1) Meshwork of terminal argyrophilic fibres.

2) Meissner’s type tactile corpucles.

3) Krause type end bulbs – temperature.

4) Encapsulated spindle receptors.

Lymphatic drainage of the gingiva :-

Begins in the lymphatics of the connective tissue papillae and drain into the

regional lymph nodes [particularly the sub maxillary group]. In addition,

Page 34: GINGIVA 1 / orthodontic courses by Indian dental academy

lymphatics just beneath the junctional epithelium extend into periodontal ligament

accompany the blood vessels.

Functions of gingiva:-

1) The gingiva is located around the necks of each tooth and is structured to

resist the forces of mastication.

2) The gingiva coupled with tongue and palate in mastication as a support for

bolus of food, food is deflected from the gingiva to the tongue and is in

turn, forced between the teeth.

3) The gingiva has sensory function, as it is well innervated with pain, touch

and temperature receptors. This capability for sensitivity offers protection.

4) The gingiva acts as a compartment and functions to protect the

periodontium from the oral cavity.

Defense mechanism:-

1) The humoral arm which represents the production of gingival fluid.

2) The cellular arm which represents the emigration of neutrophilic

granulocytes via junctional epithelium. Both these arms keep a 24 hours,

watch on the periodontal health.

The gingival fluid is an inflammatory exudate, the amount of fluid is increased

when there is inflammation present. It is increased by mastication of coarse food,

tooth brushing, ovulation, hormonal contraceptives, smoking etc. Drugs like

tetracycline and metronidazole are excreted by gingival fluid. Leucocytes have

been found to have phagocytic and killing capacity. Therefore they constitute a

major protective mechanism against extension of plaque into the gingival sulcus.

Salivary secretions are protective in nature it exerts a major influence on plaque by

1) mechanically cleansing the exposed oral surfaces

2) buffering the acids produced by bacteria

3) controlling bacterial activity.

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Position of gingiva:-

The position of gingival refers to the level at which the gingival margin is

attached to the tooth surface. Exposure of the tooth by apical migration of gingival

is called gingival recession on atrophy.

According to concept of continuous eruption, it consists of

Active eruption: Movement of teeth in the direction of occlusal plane.

Passive eruption: Exposure of teeth by apical migration of gingival.

Passive eruption is divided into 4 stages.

1) Stage 1: The teeth reach the line of occlusion. The junctional epithelium

and base of the gingival sulcus are on the epithelium.

2) Stage 2: The junctional epithelium proliferates so that part is on the

cementum and part is on the enamel. The base of the sulcus is still on the

enamel.

3) Stage 3: The entire junctional epithelium in on the cementum and the base

of the sulcus is on the CEJ

4) Stage 4: The junctional epithelium proliferates on the cementum. The base

of the junctional epithelium is on the cementum, a portion of which is

exposed. It is accompanied by degeneration of gingival and PDL fibres and

their detachment from the tooth.

Age changes in the gingiva:-

1) Diminished keratinization.

2) Reduced or unchanged amount of stippling

3) Increased width of attached gingival.

4) Reduced connective tissue cellularity.

5) Greater amount of intercellular substance

6) Reduced O2 consumption

O2 consumption of normal gingiva ---- Q02 1.6 -+ 0.37.

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O2 consumption of skin -------- QO2 1.48 +_ 0.48.

7) An increase or no change in the mitotic index of gingival epithelium.

Cuticular structures on the tooth:

The term cuticle is defined as thin, acellular structure with a homogenous

matrix, sometimes enclosed within clearly demarcated linear borders.

Classification: (List garten)

1) Acquired coatings of exogenous origin: Such as saliva, bacteria, calculus,

surface stains.

2) Coatings of developmental origin: Are those normally formed as part of

tooth development.

such as 1) Reduced enamel epithelium

2) The coronal cementum and

3) The dental cuticle.

1) Reduced enamel epithelium: After enamel formation is completed, the

ameloblastic epithelium becomes reduced to 1or 2 layers that remain attached to

the enamel surface by hemidesmosomes and a basal lamina. This reduced enamel

epithelium consists of post secretary ameloblasts and cells from stratum

intermedium of the enamel organ.

2) coronal cementum: In some animals the reduced enamel epithelium disappears

very rapidly, there by placing the enamel in contact with the connective tissue.

Connective tissue cells then deposit a thin layer of cementum known as coronal

cementum on the enamel. In humans, thin patches of afibrillar cementum may be

seen in the cervical ½ of crown.

3) The dental cuticle: consists of a layer of homogeneous organic material of

variable thickness, overlying the enamel surface, it is non mineralized and is not

always present. Studies have shown the dental cuticle to be proteinaceous and it

may be an accumulation of tissue fluid components.

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Properties, functions and defense mechanisms.

As the gingival represents both the most peripheral part of the periodontium

and a portion of oral mucous membrane its properties and functions are 2 fold.

I) As part of the oral mucosa: A) It protects the supporting tissue from the oral

environment. It is subjected to friction and pressure in the masticatory process. It’s

densely collagenous lamina propria, peripheral sensory innervations and

keratinization help in the adaptation to these physical requirements.

B)Gingiva is a mucostable tissue because, of its firmness, scalloped contour, close

adaptation and attachment to the understanding structures.

C) Gingival tissue fulfill the functions of sensitivity and resistance

II As part of the periodontium:-

A) The gingiva exhibits functional properties. 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 generature forces resulting in mesial drift.

B). It maintains gingival and periodontal health by means of various defense

mechanisms operating within the gingival tissue.

Defense mechanism:-

The gingival tissue is constantly subjected to mechanical and bacterial aggression.

Resistance to these actions is provided by the

- Sulcular fluid

- Saliva

- Epithelial surface

- Permeability of junctional and sulcular epithelium

- Leukocytes.

3) The gingival sulcular fluid contains proteins, specific antibodies and antigens,

enzymes and cellular elements. leucocytes have through the gingival fluid

leucocytes have been found to have phagocytic and killing capacity.

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Renewal of gingival epithelium: The oral epithelium undergoes continuous

renewal. Its thickness is maintained by a balance between new cell formation in

the basal and spinous layers and the shedding of old cells at the surfaces.

The mitotic activity exhibits a 24hr periodicity with highest and lowest rates.

Occurring in the morning and evening respectively, The mitotic rate is higher in

non-keratinized area and increased in gingivitis. Clinically the surface of attached

gingiva resembles that of an orange peel. It is characterized by numerous,

irregularly distributed, finely grained or coarse round to oval or even split like

depressions- stipples. They are about 0.6 to 1.4mm in diameter or length and 1.5

mm or 3.5 mm in depth. More on facial aspect of maxillary anterior and less on

anterior mandibular. Stippling is a form of adaptive reinforcement on

specialization for function loss of stippling is a common sign of gingival disease.

Clinical considerations :-

When we performing dental treatment like cavity preparation and crown cavity

proper protection of gingival is necessary. If there is any damage of the gingival

tissue it sometimes will lead to periodontal disease. While preparing crown just

below free gingival care must be taken not to damage attached gingival tissue.

Proper contact should be maintained to prevent food lodgment so as to avoid

gingival damage. When using matrix bands, wedges and separators care must be

taken to prevent damage. If there is any hypertrophy it should be removed before

restorative treatment.

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CORRELATION OF NORMAL AND CLINICAL MICROSCOPE FEATURES

Appearance in healthy gingiva Microscopic features Changes in

disease/

clinical

appearance

Cause for change

A) color

Uniformly pale pink/ coronal

pink. melanin pigmentation

occurs as a diffuse, deep

purplish discoloration (or) As

irregularity shaped brown and

light brown patches

a) vascular supply

b)Thickness and

keratinisation of

epithelium presence

of pigment

containing cells

Chronic

bluish pink /

bluish red.

- Vessels

- Engorged

- Blood flow

sluggish

- Venous

return

impact

B). Size

Corresponds to the sum total

of bulk of acellular and inter

cellular elements & their

vascular supply.

Enlarged -Edematous

inflammation fluid

cellular exudates

hemorrhage.

Page 40: GINGIVA 1 / orthodontic courses by Indian dental academy

C). Shape

Marginal gingival knife edge,

follows a curved line around the

tooth

Governed by the

proximal tooth

surface and the

location and shape of

gingiva embrasure

Rolled/

Rounded

Inflammation

changes edema or

fibrous

D). consistency

Firm and resilient

E).Surface texture The gingiva presents a

textured surface with stippling like that of an orange peel(attached gingiva). Marginal gingiva is not stippled

The collagenous

nature of lamina

propria and its

contiguity with the

periosteum of the

alveolar bone.

Alteration of

rounded protrusion

& depression in

gingival surface.

Soft,spongy

red color.

smooth and

shiny surface

when pressed

with a probe.

Absent in

infancy and

old age

Edematous fluid

between cells in

the connection.

Summary and conclusion

Hence during clinical practice, focus should be placed not only on the hard

tissues, but also on the prime structures of the periodontium especially the gingiva.

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REFERENCES:

Textbook of Oral Histology and Embryology - Orbans.

Clinical Periodontology – Glickman.