gingiva seminar final first october 2015

INTRODUCTIONThe gingiva, in health, normally covers the alveolar

bone and tooth root to a level just coronal tothe cementoenamel junction

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CONTENTS Definition

Function

Clinical Features

Histological features

Structure and Characteristics Of Gingival

Epithelium

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CONTENTS

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Gingival connective tissue

Blood supply

Nerve supply

Lymphatic drainage

Correlation of normal clinical and microscopic

features

References

DEFINITIONS OF GINGIVA

Is the part of oral mucosa that covers the alveolar processes of jaw and surrounds the neck of teeth.

CARANZA-

Is that part of masticatory mucosa covering alveolar processes and the cervical portions of teeth.

LINDHE6

DEFINITIONS OF GINGIVA

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It provides physical barrier to the infection

Allows a selective interchange with oral environment

Protects the deeper structure

Play an active role in innate host defense mechanism

Epithelial cells responds to bacteria by 1. Increased proliferation 2. Changes in differentiation 3 . Cell death

MACROSCOPIC ANATOMY OF GINGIVA

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CLINICAL FEATURES1)MUCOGINGIVAL JUNCTION

2)INTERDENTAL GINGIVA.3)FREE GINGIVAL GROOVE

4)ATTACHED GINGIVA.

5)ALVEOLAR MUCOSA

6) MARGINAL GINGIVA.

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Anatomically the gingiva is classified into Anatomically the gingiva is classified into three distinct domains three distinct domains :

• The free marginal gingiva

• The interdental gingiva

• The attached gingiva12

MARGINAL GINGIVAIs the terminal edge or the border of the gingiva

surrounding the teeth in collar like fashion.

Usually about 1mm wide it forms the soft tissue wall of the gingival sulcus.

In health, is knife-edged in contour, firm in consistency, and smooth in texture

It is demarcated from the adjacent attached gingiva by a shallow linear depression the free

gingival groove13

CLINICAL PRESENTATION OF MARGINAL GINGIVA

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The attached gingiva is demarcated in the coronal direction, by the free gingival groove but its present in only 30-40% of adults

The free gingival groove is often most pronouncedon the vestibular aspect of the teeth, occurring mostfrequently in the incisor and premolar regions of the

mandible, and least frequently in the mandibularmolar and maxillary premolar regions 15

GINGIVAL SULCUS

The gingival sulcus is the shallow crevice or spacearound the tooth bounded by the surface of the toothon one side and the epithelium lining the free marginof the gingiva on the other.

It is V shaped and barely permits the entrance of a

periodontal probe.

The clinical determination of the depth of the gingival sulcus

is an important diagnostic parameter.

The probing depth of a clinically normal gingival

sulcus in humans is 2 to 3 mm 16

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DEVELOPMENT OF GINGIVAL SULCUS The gingival sulcus is formed when the

tooth erupts into the oral cavity.

At that time the junctional epithielium and reduced enamel epithelium form a broad band attached to the tooth surface from near the tip of the crown to the cementoenamel juntion.

In fully erupted tooth the sulcus consist of the shallow space that is coronal to the attachment of the junctional epithlium., bounded by the tooth on one side and the sulcular epithelium on the other .

INTERDENTAL GINGIVA

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The interdental gingiva can be pyramidal or can have a “col” shape

Occupies the gingival embrasure which is interproximal space beneath the area of

tooth contacts

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Tip of the papilla is beneath the contact point, the latter presents a valley like depression that connects the facial & lingual papilla ,Mesial & distal surfaces are slightly concave

The lateral borders & tips of the interdental papillae are formed by the marginal gingiva

INTERDENTAL GINGIVA

In anterior region the interdental papilla is of pyramidal form while in the molar regions, the papillae are more flattened in the

buccolingual direction 20

ATTACHED GINGIVA

The width of the attached gingiva is another important clinical parameter. It is the distance between the

mucogingival junction and the projection on the external surface of the bottom of the gingival sulcus or the

periodontal pocket. 21

ATTACHED GINGIVA:It is continous with the marginal gingiva extends in the apical direction to the mucogingival junction where it becomes continous with alveolar( lining ) mucosa

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It Is Firm & Resilient, tightly attached to the underlying

periosteum of alveolar bone

It extends upto the alveolar mucosa, from alveolar

mucosa it is demarcated by the Mucogingival junction

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How to measure the width of attached gingiva :

Measurement approach:1. By using schiller’s potassium iodine solution2. Tension test- this is done by stretching the lip or

cheek to demarcate the mucogingival line and to see for any movement of the gingival margin

3. Roll test or tiggling testIt is done by pushing the adjacent mucosa coronally with a dull instrument.If the gingiva moves – inadequate`

WIDTH OF ATTACHED GINGIVA

Width of attached gingiva increases with age24

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Resistance to products of inflammationGives support to the marginal gingivaHelps to withstand functional stressResistance to tensional stresses.Provides solid base for movable alveolar mucosaTo dissipate the pull on the gingival margin created

by the muscles of the adjacent alveolar mucosa. Helps to prevent soft tissue recession and

attachment lossHelps in connective tissue attachment

SIGNIFICANCE OF ATTACHED GINGIVA

Because the mucogingival junction remains stationarythroughout adult life, changes in the width of the

attached gingiva are caused by modifications in theposition of its coronal end.

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• The gingival epithelium can be studied under three headings :

GINGIVAL EPITHELIUM

Oral epithelium

Sulcular epithelium

Junctional epithelium

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Functions and Features of Gingival Epithelium Functions Mechanical, chemical, water, and microbial barrier Signaling functions

Architectural Integrity Cell-cell attachments Basal lamina Keratin cytoskeleton

Major Cell Type Keratinocyte

Other Cell Types Langerhans cells Melanocytes, Merkel cells

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Constant Renewal

Replacement of damaged cells

Cell-Cell Attachments

Desmosomes, adherens junctions

Tight junctions, gap junctions

Cell-Basal Lamina

Synthesis of basal lamina components

Hemidesmosome

Functions and Features of Gingival Epithelium

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Oral epithelium extends from the mucogingivalJunction to the tip of the gingival crest and is subdivided into the free marginal gingiva and theAttached gingiva.

Sulcular epithelium lines the gingival sulcus and extends from the tip of the gingival crest to coronal most portion of the junctional epithelium.

Junctional epithelium extends from the base of the gingival sulcus to an arbitrary point approximately 2.0 mm coronal to the alveolar bonecrest and is closely adapted to the tooth surface to form sealing and attachment functions.

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COMPLETELY ERUPTED TOOTH.-

Sulcus with epithelial debris (S)

Cementum (c)

Epithelial rests (ER)

Junctional epithelium (JE)

Oral epithelium (OE)

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SC- STRATUM CORNEUMSG-STRATUM GRANULOSUM

SS-STRATUM SPINOSOUMSB-STRATUM BASALE

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The basal layer is made up of cells that synthesize DNA and undergo mitosis, thus providing new cells. Most of the new cells are generated in the basal layer.

STRATUM BASALE (ST.GERMINATIVUM)

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The intercellular spaces - are large & distended;

thus desmosomes are made more

prominent & these cells are given a prickly

appearance.

The spinous (prickle) cells resemble a

cockleburr or sticker that has each spine ending

at a desomosome.

Spinous cells are the most active in protein

synthesis.

Contains numerous dense granules –

keratinosome or odland bodies ( orbans 10th ed)

STRATUM SPINOSUM

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STRATUM GRANULOSUM Cells are larger and flatter.

Cells show increase in maturation. Nuclei shows signs of degeneration and

pyknosis.

Cytoplasm is predominantly occupied by the

tonofilaments & tonofibrils.

Cells contain large no’s of small granules –

keratohyalin granules- these

granules help to form the matrix for the

numerous keratin fibers found in the

superficial layers

( Orbans 10th ed)38

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Cells are very flat ,devoid of nuclei, full of keratin filaments surrounded by a matrix may be termed epithelial squamae & are dehydrated. itdoes not synthesize protein.

These cells are shed (the process of desquamation),

necessitating constant turnover of epithelial cells.

Str corneum provides the mechanical protective function to

the mucosa.

Varies in thickness (upto 20 cells).

Keratinocytes increase in volume in each successive layer.

( Lindhe 5th ed)

STRATUM CORNEUM

STRATUM CORNEUM

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•Corneocytes are mainly formed by bundles of keratin tonofilaments embedded in amorphous matrix of filagrin & surrounded by resistant envelop made up of keratolinin & involucrin.

•Inter Connected through desmosomes

DESMOSOMES

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The keratinocytes are interconnected by structures on the cell periphery called as desmosome, like the adherens junction, they possesses calcium ion-dependent cell adhesion molecules that interact with similar molecules in the adjacent cell.

It consist of two adjoining hemidesmosomes separated by a zone contaning electron dense granulated material

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In addition outer and inner leaflets of the cell and attachment plaque,represent granular and fibrillar material in the cytoplam

DESMOSOMES

TIGHT JUNCTIONS

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Tight junctions (zona occludens )are less frequently observed form of epithelial cell connections

The tight junction is a site where the membranes of two cells come very close together

The outer leaflets of the membranes of the contacting cells fuse

Act as a barrier so that materials cannot pass between two interacting cells

GAP JUNCTIONS

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The basic building block of each gap junction is the

connexin subunit.

Six of these in each of the membranes of two

neighboring cells come together, and then the group of

six connexins in one cell interact with a comparable

hexamer in the other cell resulting in the formation of a

channel

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•This channel allows direct

cytoplasmic communication

among the cells; small

molecules of 1,500 daltons or

less can pass through the

channel of each gap junction

• Opening or closing can be

controlled locally in the cell.

GAP JUNCTIONS

BASAL LAMINA

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The epithelium is joined to the underlying connective tissue by a basal lamina 300 to 400 Å thick

The basal lamina consists of lamina lucida and lamina densa. Hemidesmosomes of the basal epithelial cells abut the lamina lucida, which is mainly composed of the glycoprotein laminin.

The lamina densa is composed of type IV collagen.

The basal lamina, clearly distinguishable at the ultrastructural level, is connected to a reticular condensation of the underlying connective tissue fibrils (mainly collagen type IV) by the anchoring fibrils.

BASAL LAMINA

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The basal lamina between epithelium and connective tissue

CELL TYPE OF GINGIVAL EPITHELIUM

The principal cell type of the gingival epithelium,as well as of

other stratified squamous epithelia, is the keratinocyte.

Other cells found in the epithelium are the clear

Cells or nonkeratinocytes, which include:

1 Langerhans cells2 Merkel cells3 Melanocytes4 Lymphocyte AND PMNLS

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KERATINOCYTE

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KERATINOCYTE

ROLE OF KERATINOCYTEThe main function of the gingival epithelium is

to protect the Deep structures while allowing a selective interchange with the Oral environment. This is achieved by proliferation and differentiation of the keratinocyte.

• PROLIFERATION - Of keratinocytes takes place by mitosis in the basal layer and less frequently in the suprabasal layers, where a small proportion of cells remain as a proliferative compartment while a larger number begins to migrate to the surface.

• DIFFERENTIATION - Involves the process of keratinization, which consists of a sequence of biochemical and morphologic events that occur in the cell as it migrates from the basal layer

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Keratinization can be defined as expression and synthesis of keratin proteins in the basal layer of cell, their chemical composition in the upper layer & their interaction with keratohyalin granules & formation of filamentous matrix structure in the interior of corneocyte and strenghtening of the envelope.

KERATINIZATION

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Also called as “CORNIFICATION”

Differantiation process rather than degeneration

Process of protein synthesis→Requires

energy→dependent on functional cells containing nucleus

& organelles

Cell migrate from basal to superficial→biochemical &

morphological events takeplace

Cytoplasmic proteins tranform into keratin filaments

Cytoplasm & nucleus both decompose.

SALIENT FEATURES

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CLINICAL SIGNIFICANCE OF KERATINIZATION OF GINGIVA:

The main function of the gingival epithelium is to protect the deep structures while allowing a selective interchange

with the oral environment. This is achieved by proliferation and differentiation of keratinocyte

The gingiva is exposed to heavy mechanical stresses during mastication.moreover the epithelial attachment of tooth is

relatively weak & susceptible to injury ;can cause permanent damage.

Thus keratinization of gingiva may afford relative protection.

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The keratinized gingiva on the facial aspect of teeth extend from gingival margin to MGJ. It is often claimed that presence of zone of atleast 2mm of keratinized gingiva is necessary for the maintainance of gingival health.

Lang & Loe(1992) support this whereas others authors (Miyasatto 1977,Grey & Besmimoulin 1980, Doffman et al 1980) suggests that there is no requirement for minimal width-provided accumalation of plaque is inhibited.

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Keratins family of 20 polypeptides, divided into acidic &

basic sub families

Basic or neutral keratins are numbered K1-K18

Acidic keratins numbered k9-k19

Oral gingival epithelium- Expresses k1,k2,

k5,k6,k8,k10,k11,k14,k16, K18 & k19

EXPRESSION OF KERATINS IN GINGIVA

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Oral sulcular epithelium- expresses k4,k5,k6,k13,k14,k16

& k19

Oral junctional epithelium- expresses k5,k14,k13 & k19

Lining mucosa- expresses k4/k13

Masticatory mucosa- expresses k1/k10

EXPRESSION OF KERATINS IN GINGIVA

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. K19 is present ;Absent in keratinized epithelia.

Lacks K1, K2 & K10-K12

-It contains K4 & K13-eosophageal type cytokeratines.

SULCULAR EPITHELIUM

It also expresses K19.

K6 & K16-Linked to highly proliferative epithelia;Absent in junctional epithelia though its turnover is high.

K5 & K14-Stratificetion type specific are present.

JUNCTIONAL EPITHELIUM

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PARAKERATINI Z ATION:

The stratum corneum retains pkynotic nuclei and the keratohyaline granules are dispersed, not giving rise to stratum granulosum.

NON-KERATINIZED EPITHELIUM

Neither granulosum nor corneum strata and superficial cells have viable nuclei.

ORTHOKERATINIZATION:

Similar to that of skin with no nuclei in the stratum corneum and a well-defined stratum granulosum.

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DIFFERENT CELL TYPES

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A,B- GINGIVAL LANGERHAN CELLSC - PIGMENT CONTAINING- MELANOCYTESD - MERKEL CELLS

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LANGERHAN CELLS

They are dendritic cells located among keratinocytes at suprabasal levelThey belong to mononuclear phagocyte system as modified monocytes derived from bone marrowConsidered as macrophages with antigenic propertiesAlso antigen presenting cell for lumphocytesDuring inflammation quantitative and qualitative changes seen in gingival epithelial langherhan cells

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LANGERHAN CELL IN ACTION

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MELANOCYTESMelanocytes which originate from neural crest cells are dendritic cells located in the basal and spinous layers of the gingival epithelium.

They synthesize melanin in organelles called premelanosomes or melanosomes.

These contain tyrosinase, which hydroxylates tyrosine to dihydroxyphenylalanine (dopa), which in turn is progressively converted to melanin. . \

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Merkel cells are located in clusters at the tips ofRete ridges of gingival oral epithelium .

Their origin remains controversial, with reports suggesting origins from either neural crest cells or epithelial sources .

These cells form close associationswith intraepithelial nerve endings, forming the epidermal merkel cell–neurite complexes . While it is generally accepted that these Complexes are involved in mechano-perception/tactile perceptors

MERKEL CELLS

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MERKEL CELLS

Transients - inflammatory cells.

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Lymphocyte –large circular nucleus scant cytoplasm with few organelles

Polymorphonuclear leukocytes & mast cells are other inflammatory cells

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ORAL(OUTER) EPITHELIUMCovers the crest and outer surface of the marginal gingiva and the surface of attached gingiva It is keratinized or parakeratinized or presents various combination of these conditionsThe degree of gingival keratinization diminishes with age and the onset of menopause

The oral gingival epithelium is cornified, impermeable to water – soluble substances and attached firmly to a base of dense connective tissue

Keratinization of oral mucosa varies in different areas in the following order – palate, gingiva, ventral aspect of tongue and cheek

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ORAL(OUTER) EPITHELIUM

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It shows lowest rate of proliferation in comparison to the junctional epithelium and oral sulcular epithelium

Basal cell attach to the basal lamina through many desmosomes

Keratins K1, K2 and K10 to K12K6 and K16K5 and K14 K19 present in parakeratinized area

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Oral Sulcular Epithelium extends from the crest of the

marginal gingiva to the Junctional Epithelium

Healthy gingiva is characterized by a shallow gingival

sulcus less than 3mm

Does not contain keratohyaline granules, merkel cells

Is normally nonkeritinized

ORALSULCULAR EPITHELIUM

ORALSULCULAR EPITHELIUM

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Is more permeable to water soluble substances than the Oral Gingival Epithelium

Contains K4,K13,K19

Contains increased lysosomal activity

Has potential to keratinize

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GingivaPart -2

CONTENTS

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Development of gingiva

Junctional epithelium

Gingival connective tissue

Blood supply

Nerve supply

Lymphatic drainage

Correlation of normal clinical and microscopic features

Ageing and gingiva

Conclusion

References

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DEVELOPMENT OF GINGIVA

The dental papilla and dental follicle, the non-ectodermal components of the tooth buds, are formed by concentration of neural crest ectomesenchymal cells “Schroeder Moxham & Grant”

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The dental organ is the formative organ of enamel,

The dental papilla is the formative organ of the dentin–pulp

complex,

The dental follicle is the formative organ of the attachment

apparatus (the cementum, the periodontal ligament, and the

alveolarbone proper)


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As an erupting tooth approaches the oral epithelium,the

enamel epithelium rapidly proliferates, forming the thick

reduced enamel epithelium.

As the crown erupts further, the reduced enamel epithelium

overlying the enamel fuses with the oral epithelium, undergoes

transformation, and establishes the dentogingivaljunction

forming the junctional epithelial cells.


JUNCTIONAL EPITHELIUM The junctional epithelium consists of a collarlike band of

stratified squamous nonkeratinizing epithelium.

• 3 to 4 layers thick in early life, but the number of layers increases

with age to 10 or even 20 layers.

• Also, the junctional epithelium tapers from its coronal end,it may

be 10 to 29 cells wide to one or two cells at its apical termination,

located at the cementoenamel junction in healthy tissue

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The junctional epithelium is attached to the tooth surface by means of an internal basal lamina

To the gingival connective tissue by an external basal lamina.

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The attachment of the junctional epithelium to the tooth is reinforced by the gingival fibers, which brace the marginal gingiva against the tooth surface. For this reason, the junctional epithelium and the gingival fibers are considered a functional unit, referred to as the dentogingival unit

Outer most cells of junctional epithelium produce an internal basal lamina& anchor to it through the hemidesmosomes


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Internal basal lamina contains glycoproteins,laminin & proteoglycans

External basal lamina contains collagen type iv , heparin sulfate proteoglycon, laminin& fibronectin

Junctional epithelium contains moderately well developed lysosomal system & participate in phagoytosis of material from intercellular space

Length of junctional epithelium ranges from 0.25 to 1.35mm


JUNCTIONAL EPITHELIUMThe junctional epithelium differs from both the oral sulcular

epithelium and the oral gingival epithelium by- The size of the cells in the junctional epithelium is, relative to the tissue volume, larger than in the oral epithelium. The intercellular space in the junctional epithelium Is, relative to the tissue volume, comparatively wider than in the oral epithelium. The number of desmosomes is smaller in the junctional epithelium than in the oral epithelium

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It forms an epithelial barrier against plaque bacteria.

It allows access of gingival fluid, inflammatory cells, and

components of the immunologic host defense to the gingival

margin.

Cells exhibit rapid turnover, which contributes to the host-

parasite equilibrium and rapid repair of damaged tissue.

Cells have an endocytic capacity equal to that of macrophages

and neutrophils, and that this activity might be protective in

nature.86

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“Gottlieb (1921)” first coined the term epithelial attachmentThe term epithelial attachment refers to the attachment apparatus, i.e. internal basal lamina & hemidesmosomes that connects the junctional epithelium to the tooth surface.

It consists of hemidesmosomes at the plasma membrane of the cells directly attached to the tooth (DAT cells) and a basal lamina-like extracellular matrix, termed the internal basal lamina, on the tooth surface

EPITHELIAL ATTACHMENT APPARATUS

http://www.dental.pitt.edu/informatics/periohistology/en/glossary.html

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HEMIDESMOSOMES

The dento-epithelial junction is the only site in the

mammalian body where epithelial cells adhere by means

of hemidesmosomes and a basal lamina to a

nonrenewable hard tissue. “Listgarten “et al1966

Hemidesmosomes are specialized structures through

which epithelial cells adhere to the underlying

connective tissue.”Schwarz” et al 1990

HEMIDESMOSOMES

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Hemidesmosomes are exclusively located in areas of

cell-substratum interactions

The hemidesmosome is a complex junction containing many

proteins

The hemidesmosome is more than just a stable anchor, as it

may also be the site of signal transduction, mediated by its

α6β4 integrin component

“Jones, J. C.R., Hopkinson, S. B. and Goldfinger, L. E”. (1998)

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Structural and molecular composition of the epithelial attachment apparatus at DAT cell

N-nucleus of a DAT cell,IF-cytoplasmic keratin filamentsThe hemidesmosomes at the plasma membrane are associated with the a6b4 integrin that communicates with Ln-5= laminin 5 located mainly in the internal basal lamina, the extracellular domain (?) for B180 is a collagenous protein (perhaps type VIII), that has not yet been definitely characterized. LL = lamina lucida, LD = lamina densa, SLL = sub lamina lucida, IBL = internal basal lamina.

DYNAMICS (TURNOVER RATE) OF JE

• The turnover rate of JE cells is exceptionally rapid. In non-human primates it is about 5 days (twice that of oral epithelium).

• The DAT cells express a high density of transferrin receptors supporting the idea of active metabolism and high turnover.

• DAT cells have an important role in tissue dynamics and reparative capacity of the JE.

• The existence of a dividing population of DAT cells in a suprabasal location in several layers from connective tissue is a unique feature of JE. 91

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(1)The daughter cells are produced by dividing DAT cells and replace degenerating cells on the tooth surface.

(2) The daughter cells enter the exfoliation pathway and gradually migrate coronally between the basal cells and the DAT cells to eventually break off into the sulcus

(3)Epithelial cells move/migrate in the coronal direction along the tooth surface and are replaced by basal cells migrating round the apical termination of the junctional epithelium.

Mechanism of JE cells turnover

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Antimicrobial defense mechanisms of JE

By rapid cell divisionFunneling of of JE cells towards the sulcus hinders bacterial colonizationActive antimicrobial substances produced by JE cellsEpithelial cells activated by microbial secretions eg IL6 IL-1 &TNF that attract lymphocytes & PMN

ROLE OF GINGIVAL CLEVICULAR FLIUD

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REPAIR OF THE JUNCTIONAL EPITHELIUMAFTER SURGERY

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“Listgarten” (1972) in his studies on young monkeys found that the JE was completely re-established at 12 days from an apical extension of the oral epithelium .

If the JE is merely separated and not removed, the reattachment appears to occur rapidly from the apical region coronally with complete reformation of the hemidesmosomal attachment within 5days “Taylor and Campbell” 1972

Following periodontal surgical treatment wound healing generally leads to formation of long junctional epithelium

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GINGIVAL CONNECTIVE TISSUE

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Extra cellular compartment Fibers -60% Ground substance -35%

Cellular compartment -5% Fibroblasts -65% Mast cells Macrophages Inflammatory cells

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“Gargiulo” et al. (1961) determined that the average mean measurements for –

1.Sulcus depth was 0.69 mm;2.The epithelial attachment, 0.97 mm3.Connective tissue attachment 1.07 mm.

Fiber bundles are densely populated by fibroblasts &

consist mainly type I & IV collagen

Type I - Represents mainly dense fibers

Type IV - Related to connective tissue


FIBROBLASTS

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Gingival fibroblasts are

phenotypically heterogeneous,

and these fibroblast

subpopulations may play

different roles in tissue

maintenance, regeneration and

pathologies.

STRUCTURE AND ORIGIN OF FIBROBLAST• Fibroblasts are of mesenchymal origin and play a major role

in the development, maintenance and repair of gingival connective tissues.

• They have a typical elongated or spindle shape and, consistent with their high level of synthetic activity, have prominent rough endoplasmic reticulum and golgi apparatus.

• Their cytoplasm is usually rich in numerous mitochondria vacuoles and vesicles

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FUNCTIONS OF FIBROBLASTS• Responsible for synthesis of the extracellular matrix.

• Maintenance of tissue homeostasis by phagocytosis of collagen

by fibroblasts during tissue turnover and remodeling.

• Gingival fibroblasts synthesize a wide range of matrix

metalloproteinases

• These cells have the ability not only to respond to paracrine

signals but may also synthesize and secrete a number of growth

factors that further dictate cell activity in an autocrine manner

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PROPERTIES OF FIBROBLASTS

Apart from regulating matrix synthesis and remodeling, fibroblasts possess two other properties critical to their function -:

An ability for site directed migration (chemotaxis)

Attachment to various substrata

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Numerous in the connective tissue of the oral mucosa and gingiva

These are responsible for the production of certain component of matrix

Produce vasoactive substances which can affect the function of the microvascular system and control the flow of blood through the tissue

MAST CELLS

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MACROPHAGES AND HISTIOCYTES

Are present in the gingival connective tissue as components of the mononuclear phagocyte system (reticuloendothelial system)

Macrophages have –

Phagocytic function Synthetic function

Phagosomes(PH)

INFLAMMATORY CELLS

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Neutrophils can be seen in relatively high numbers in both the gingival connective tissue and the sulcus Small foci of plasma cells and lymphocytes are found in the connective tissue near the base of the sulcus These inflammatory cells usually are present in small amounts in clinically normal gingiva.

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Fills the space between fibers and cells

Has high content of water

Produced by fibroblasts some components by mast

cells and others derived from blood

Main constituents are

1.PROTEOGLYCANS

2.GLYCOPROTEINS

EXTRA CELLULAR COMPARTMENT

GROUND SUBSTANCE MATRIX

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As a medium in which connective tissue cells and

fibers are embedded.

For maintenance of the normal function of

connective tissue

For transposition of water, electrolytes, nutrients,

metabolites to and from the cells.

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PROTEOGLYCANS

The proteoglycans perform following functions-

1. Regulate diffusion and fluid flow through the matrix

2. Determinants for the fluid content of the tissue

3. Maintenance of the osmotic pressure

4.They exert resistance towards deformation, thereby

serving as regulators of the consistency of the

connective tissue

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GLYCOPROTEINS Fibronectin (FN) is the principal glycoprotein in

connective tissue, serving to orient fibroblasts to

collagen and provide protein attachment for cell-matrix

adhesions.

FN may influence the migration of fibroblasts and play

a crucial role inmaintaining structural integrity of CT.

Plays a role in the alignment of collagen fibers

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FIBERS OF MATRIXThe fibers of connective tissue can be divided into-

1.Collagen2.Reticular3.Elastic4.Oxytalan

COLLAGEN FIBERS- The collagen fibers predominate in the gingival connective tissue and constitute the mostessential components of the periodontium.

Cementoblasts and osteoblasts are cells which alsopossess the ability to produce collagen.

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COLLAGEN TYPE I forms bulk of lamina propria and

collagen type iv branches between it and is continous with

fibers of basement membrane

Densely packed collagen bundles that are anchored into the

acellular extrinsic fiber cementum just below the terminal

point of the junctional epithelium form the connective

tissue attachment.

The stability of this attachment is a key factor in limiting the

migration of junctional epithelium.

“Cho MI ,Garant “PR 2000

FIBERS OF MATRIX

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RETICULIN FIBERS:Present in epithelium connective tissue interface and endothelium connective tissue interface

ELASTIC FIBERS:Present in association with the blood vesselsAre absent in the gingiva coronal to the mucogingival

junctionOXYTALAN FIBERS

Are scarce in gingiva and are immature fibersPresent numerously in periodontal ligamentCourse mainly parallel to long axis of tooth

SYNTHESIS AND COMPOSITION OF COLLAGEN FIBERS

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The smallest unit, the collagen molecule, is often

referred to as tropocollagen.

Tropocollagen synthesis takes place inside the fibroblast

the polymerization of tropocollagen molecules to

collagen fibers takes place in the extracellular

compartment.

SYNTHESIS AND COMPOSITION OF COLLAGEN FIBERS

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Tropocollagen molecules are

aggregated longitudinally to

protofibrils (pf), which are

subsequently laterally aggregated

parallel to collagen fibrils (cfr)

. The collagen fibers (cf) are

bundles of collagen fibrils, aligned in

such a way that the fibers also

exhibit a cross-banding.

TROPOCOLLAGEN

PROTOFIBRILS

COLLAGEN FIBRILS

COLLAGEN FIBERS

GINGIVAL FIBERS

The connective tissue of the marginal gingiva is densely

collagenous, containing a prominent system of collagen

fiber bundles called the gingival fibers.

They consist of type I collagen

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FUNCTIONS OF GINGIVAL FIBERS

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GINGIVAL FIBER ARRANGEMENTS

Dentogingival fibers- inserted into the root surface as sharpey’s fibers and fan out from the root surface subjacent to the junctional epithelium and coronal to the alveolar crest into the gingival tissues

Dentoperiosteal fibers- inserted into the root surface and run over the alveolar crest and insert into the buccal lingual periosteum.

Alveolgingival fibers- arise at the alveolar crest and fan out into the free and attached gingivae.

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.

Circular and semicircular fibers - Are located coronal to the

transseptal fibers and run in a circumferential or semicircular

manner around the teeth

Transgingival and intergingival fibers- Closely related to

the semicircular fibers. Arise in the cementum and splay

through the interdental septum and eventually coalesce with

the semicircular fibers of the adjacent tooth

Interpapillary fibers - Run in a buccolingual direction through the interdental tissue

Periosteogingival fibers - Inserted into the alveolar periosteum and splay out into the attached gingiva

Intercircular fibers - Located both bucally and lingualy and run in a mesiodistal manner to join circular fibers of adjacent teeth

Transseptal fibers - Arise in the cementum and traverse the interdental alveolar crest and reinsert in the cementum of the adjacent tooth Hassell, 1993

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DIAGRAM SHOWING GINGIVAL FIBERS ARRANGEMENTS

BETWEEN TEETH IN ARCH

BLOOD SUPPLY• Three sources of blood supply to the gingiva are as follows:

1.Supraperiosteal arterioles -along the facial and lingual surfaces of the alveolar bone.

2. Vessels of the periodontal ligament - which extend into the gingiva and anastomose with capillaries in the sulcus area.

3. Arterioles- which emerge from the crest of the interdental septa and extend parallel to the crest of the bone to anastomose with vessels of the periodontal ligament, with capillaries in the gingival crevicular areas and vessels that run over the alveolar “Nobuto” et al. (1989),

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Arteriole - Penetrating the interdental alveolar bone to supply the interdental tissues (left)Supraperiosteal arteriole - Overlying the facial alveolar bone, sending branches to the surrounding tissue (right).

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125

Vascular networks within gingival

epithelium

Primary vascular supply is by

vessels located in

–

1 Periodontal ligament

2 Junctional epithelium

3 Subadjacent to JE

4 Gingiva

5 Alveolar bone

GINGIVAL VASCULATURE

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The arrangement of the vasculature in each of these regions varies –

Adjacent to the junctional epithelium,the vascular plexus is

composed of anastomosing post capillary venules termed the

gingival plexus.

Elsewhere in the gingiva, the capillary loops consist of an ascending arterial and descending venous component. At the arterio-venous anastamoses a glomerular-like structure

VASCULAR SUPPLY OF GINGIVA

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NERVE SUPPLY TO GINGIVA

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Max palatal aspect of incisors - Long sphenopalatine/n.pterygopalatine

Labial aspect of gingiva mandible -mental

Lingual gingiva of mandible -sublingual

Gingiva buccal aspect of molars -buccal

gingiva labial aspect of incisors, canines, premolars –superior labial

Gingiva on buccal aspect of molars- posterior superior alveolar

Palatal gingiva except incisors -greater palatine

NEURAL COMPOSITION OF GINGIVA

• Gingival connective tissues most nerve fibers are

myelinated and are closely associated with the blood

vessels.

• Nerve fibers are immunoreactive to a number of

neuropeptides substance P and neuropeptide Y

• Nerve fibers originating in the subepithelial connective

tissue may also penetrate into the junctional epithelium.

• The intraepithelial nerves are unmyelinated but do have

endings containing a number of neuropeptides 129

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NEURONAL NETWORKS WITHIN HUMAN GINGIVA

The presence of nerves and associated neuropeptides are considered to contribute a neurogenic component to the inflammatory alterations caused by mechanical, chemical and possibly emotional stimuli.

The function of intraepithelial nerves may not only be for sensory purposes, but may form networks of communicative pathways between the epithelium and underlying connective tissues

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Mandibular incisors - Sub mental

Buccal gingiva of maxilla, - Submandibular

Buccal and lingual gingiva

of mandibular premolar

and molar region

Mandibular 3rd molars - Jugulodiagastric

Palatal gingiva of maxilla - Deep cervical

GINGIVAL LYMPHATIC DRAINAGE

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GINGIVAL LYMPHATIC DRAINAGE

CORRELATION OF NORMAL CLINICAL AND MICROSCOPIC FEATURES

COLOUR - Coral pink & is produced by

• Vascular supply

• The thickness and degree of keratinization

• The presence of pigment-containing cells

According to Dummet

Gingiva-60%

Palate-61%

Mucous membrane-22% tongue-15% 133

GINGIVAL COLOUR I NDEX

DUMMETT ORAL PIGMENTATION INDEX (DOPI)• Dummett and Gupta, 1966• The criteria is as follows:• 0 = Pink tissue• 1 = Mild, light brown tissue• 2 = Medium brown or mixed pink or brown

tissue• 3 = Deep brown or blue/black tissue

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SURFACE TEXTURE • The gingiva presents a textured surface similar to an

orange peel – stippling

• The attached gingiva and central portion of interdental papilla is stippled

• The attached gingiva is stippled; the marginal gingiva is not

• It is less prominent on the lingual than the facial surfaces and may be absent in some persons 135

136

It is absent in infancy increase until adulthood and begins to disappear in old age

Microscopically, stippling is produced by alternate rounded protuberances and depressions in the gingival surface

SURFACE TEXTURE

SURFACE TEXTURE

137

Stippling is a form of adaptive specialization or

reinforcement for function.

It is a feature of healthy gingiva, and reduction or

loss of stippling is a common sign of gingival disease.

When the gingiva is restored to health after treatment,

the stippled appearance returns.

SURFACE TEXTURE

138

A strong tendency was shown in which fully keratinized tissue was associated with a dense, diffuse pattern of stippling.

However, gingiva with a dense, diffuse pattern of stippling was associated with parakeratosis as frequently as with full keratinization.

Attached gingiva with a sparse, coalesced pattern of stippling almost always had a parakeratotic surface layer. “ James R.O jop 1969”

STIPPLING AS A DIAGNOSTIC AID

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These absence of stippling does not mean that stippling cannot be used in diagnosis, but it is important to realize that it must only be used along with such other diagnostic aids as firmness, contour, density, adaptation, color 1 1 and pocket depth.

Together they build a strong foundation for a sound

diagnosis

“Greene A.H 1962”

CONSISTENCY • Firm and resilient• Collagenous nature of the laminapropria &

contiguity with the mucoperiosteum of alveolar bone determine firmness of attached gingiva

• Gingival fibers contribute to firmness of gingival margin

• An adequate width of keratinized gingiva is important for maintaining gingival health

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SIZE

• The size of the gingiva corresponds with the sum total of the bulk of cellular and intercellular elements and their vascular supply

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CONTOUR

Contour of gingiva depends on Shape of the teeth

Teeth alignment in arch

Location & area of proximal contact

Dimensions of facial & lingual gingival embrassures

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A straight line- relatively flat surface of teeth

Accentuated contour- on teeth with pronounced mesiodistal convexity& located apically

CONTOUR

GINGIVAL BIOTYPE

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The term "gingival or periodontal phenotype" was coined by “Muller”

Gingival biotype is known to be dependent upon many factors such as age, gender, growth, tooth shape, tooth position, tooth size and genetically determined factors-

• Bulky slightly scalloped marginal gingiva with short and wide teeth

• Thin highly scalloped marginal gingiva with slender teeth

IMPORTANCE OF GINGIVAL BIOTYPE

145

Knowledge of the gingival biotype is important because

–The anatomical characteristics of the periodontium,

such as gingival thickness, gingival width and alveolar

bone morphology, will determine periodontal behaviour

when submitted to -

Physical, chemical, or bacterial injury

Periodontal surgical procedures

Implant surgical procedures

Orthodontic treatment

EFFECT OF AGEING ON GINGIVA

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Gingival epithelium

Thinning and decrease in keratinizationIncrease in epithelium permeamibilityFlatttening of retepegsApical migration of junctional epithelium on root surface

Connective tissue

•Coarser and denser connective tissue

•Collagen content increases

•Rate of collagen synthesis decreases


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MICROVASCULATURE CHANGES

Blood pressure increased slightly with age

Peripheral oxygen saturation was lower in old

compared to young and middle aged


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NEURAL CHANGESThere was a decrease in the number of nerves in the

gingivae of dentulous individuals.

The nerves present showed degenerative changes such as

fibrosis, fragmentation, and reticulation.

In the edentulous gingivae, there was a marked loss of

nerves and terminal endings.“Charles N Sol Z JOPD 2006”

http://www.sciencedirect.com/science/article/pii/0022391381900913

EPITHELIAL ATTACHMENT TO IMPLANTS

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“Listgarten et al. (1991)” provided a comparison of

periodontal tissues around dental implants and the natural

dentition.

As in the natural dentition, the junctional epithelium is

attached to the implant surface by a basal lamina and

hemidesmosomes.

Based on these observations, the authors suggested that the

epithelial relationship to the dental implants was, therefore,

very similar to that of the natural dentition.

CONCLUSION

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GINGIVA – Protector,regulator or harbinger of bad news-

The manner in which the gingival epithelium not only

provides a barrier protection role but, more importantly,

initiates the earliest of signals of impending bacterial

assault to underlying connective tissues is critical.

However with ongoing bacterial accumulation the

epithelium has become the ‘‘harbinger’’of bad news and

now dictates a more concerted defense mechanism to

be activated within the gingival connective tissues.

CONCLUSION

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Should the balance tip towards uncontrolled tissue

destruction, then resorption of the alveolar bone,

together with loss of fibrous attachment to the root

surface and apical migration of the junctional epithelium

ensues.

As a result, periodontitis develops and, once again, the

Gingiva becomes the harbinger of bad news.

REFERENCES

Carranza F.A., Michael G. Newman, Clinical

peridontology 8, 9,10th edition –.

Bhaskar N.S Orbans, Oral Histology and

Embryology – S.N. Bhaskar, 10th edition.

Jan Lindhe, Clinical Periodontology and

Implant Dentistry – 4th edition.

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REFERENCESSchroeder HE, Listgarten MA: The gingival tissues:

the architecture of periodontal protection, Periodontol 2000 13:91, 1997

PollanenTM , Salonen IJ:Structure and function of tooth- epithelial interface in health and disease. periodontology 2000 31: 12-31, 2003

BartoldMP, WalshJL:Molecular and cell biology of gingiva. periodontology 200024: 28-55, 2000

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REFERENCES

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Gargiulo AW, Wentz FM, Orban B. Dimensions and relations of the dentogingival junction in humans. J Periodontol 1961;32:261.267 .

Owings JR. A clinical investigation of the relationship between stippling and surface keratinization of the attached gingiva. J Periodontol 1969; 40:588-592.

Listgarten M. Ultrastructure of the dentogingival junction after gingivectomy. J Periodont Res 1972;7:151-160.

Listgarten M, Lang N, Schroeder H. Periodontal tissues and their counterparts around endosseous implants. Clin Oral Impl Res 1991;2:1-19.

gingiva seminar final first october 2015

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