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GINGIVA IN HEALTH

Presented by:- Ganesh NairFY PGDept of Periodontology

and implantology2

Guided by:-Dr. Anita PanchalDr. Sachin K.Dr. Bhaumik NanavatiDr. Rahul ShahDr. Mansi Pathak

Contents:-• Definition• Parts of GINGIVA.• Microscopic features of gingiva• Gingival fibres.• Blood, lymphatic and nerve supply of gingiva.• Clinical features of gingiva.• Gingiva in disease• Classificaton of gingival diseases.• Bibliography

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Definitions:-

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Parts of GINGIVA:-

• Anatomically parts:-1.Marginal gingiva &

Gingival sulcus2.Attached gingiva3.Interdental gingiva

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Identification of Mucogingival junction and significance:

Mucogingival junction is identified by-• visual method (VM), • functional method (FM)/Roll test • VM after histochemical staining method (Histochemical

method).• Tension test.

VM FM HM 8

Histologic sulcus depth vs. clinical sulcus depth

• The histologic depth of a sulcus does not need to be exactly equal to the depth of penetration of the probe. The so-called probing depth of a clinically normal gingival sulcus in humans is 2 to 3 mm

• The depth of this sulcus, as determined in histologic sections, has been reported as 1.8 mm, with variations from 0 to 6 mm, other studies have reported 1.5 mm and 0.69 mm.

-Orban and kohler- 1924

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Microscopic features of gingiva:-• Main form of tissue in the gingiva is the stratified squamous

epithelium.• Major Cell Type

Keratinocyte• Other Cell Types(non keratinocyte)

Langerhans cellsMelanocytes, Merkel cells

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Keratinocyte:-

• Of ectodermal origin.• Identification: large oval nucleus with one or more nucleolii

abundance of metabolic organelles, basophilic in light microscopy.

• Functions:a) protect the deep structures while allowing a selective interchange

with the oral environment.

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• By proliferative and differentiation.1)progressive flattening of the cell with an increasing prevalence of tonofilaments,2)intercellular junctions coupled to the production of keratohyaline granules, 3)disappearance of nucleus

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Classification of gingiva on the basis of degree of keratinization:

• A complete keratinization process leads to the production of an orthokeratinized superficial horny layer similar to that of the skin, with no nuclei in the stratum corneum and a well-defined stratum granulosum.

• parakeratinized epithelia the stratum corneum retains pyknotic nuclei, and the keratohyalin granules are dispersed, not giving rise to a stratum granulosum

• The nonkeratinized epithelium (although cytokeratins are the major component, as in all epithelia) has neither granulosum nor corneum strata, whereas superficial cells have viable nuclei

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Types of keratin:• Immunohistochemistry, gel electrophoresis, and immunoblot

techniques have made identification of the characteristic pattern of cytokeratins possible in each epithelial type.

• Generally, basal cells begin synthesizing lower-molecular-weight keratins, such as K19 (40 kD), and express other higher-molecular-weight keratins as they migrate to the surface.

A (neutral-basic) B (acidic) Occurrence

keratin 1, keratin 2 keratin 9, keratin 10 stratum corneum, keratinocytes

keratin 3 keratin 12 cornea

keratin 4 keratin 13 stratified epitheliumkeratin 5 keratin 14, keratin 15 stratified epitheliumkeratin 6 keratin 16, keratin 17 squamous epitheliumkeratin 7 keratin 19 ductal epitheliakeratin 8 keratin 18, keratin 20 simple epithelium

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Keratinocyte vs. Corneocyte• Keratohyaline granules contain a histidine-rich, sulphur-poor

protein which when the cell reaches the stratum corneum becomes modified to filaggrin.

• In the sudden transition to the horny layer, the keratohyaline granules disappear and give rise to filaggrin, which forms the matrix of the most differentiated epithelial cell, the corneocyte.

• thus in the fully differentiated state, the corneocytes are mainly formed by bundles of keratin tonofilaments embedded in an amorphous matrix of filaggrin and are surrounded by a resistent envelope under the cell membrane.

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Langerhan cells:• Langerhans are dendritic cells located

among keratinocytes at all suprabasal layers.

• They belong to mononuclear phagocyte system.

• They contain elongated granules and are considered macrophages with possible antigenic properties.

• They contain g-specific granules(Birbeck’sgranules).

• They are found in oral epithelium of normal gingiva and in smaller amounts in sulcular epithelium.

• They are absent in junctional epithelium of normal gingiva.

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Melanocytes

1. Melanocytes are dendritic cells located in the basal and spinous layer of the gingival epithelium.

• Pre melanosome organelles.• These contain tyrosinase which hydroxylates tyrosine into

dihydroxyphenylalanine(dopa) which in turn is converted into melanin

• Melanin granules are phagocytosed & contained in melanophages or melanophores.

• Lacks desmosomes

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Merkel cells:

• Merkel cells located in deep layers of the epithelium(basal layer)

• Epithelial in origin• Harbor nerve endings.• They have been identified as tactile preceptors.• Small membrane bound vesicles in the cytoplasm adjacent to

nerve endings

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Layers of an epithelium• The epithelium is joined to the

underlying connective tissue by a basal lamina 300 to 400 Å thick, lying approximately 400 Å beneath the epithelial basal layer.

• The four layers:I) BASAL LAYER (STRATUM BASALE)II) PRICKLE CELL LAYER (STRATUM SPINOSUM)III) GRANULAR LAYER (STRATUM GRANULOSUM)IV) KERATINIZED CELL LAYER (STRATUM CORNEUM)

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Basal lamina:-• Ultra structurally ,basement membrane is called basal lamina.• Basal lamina is made up of a clear zone (lamina lucida) just

below the epithelial cells and a dark zone (lamina densa) beyond the lamina lucida and adjacent to the connective tissue

• Anchoring fibrils , which forms loops and are inserted into the lamina densa.

• Lamina lucida is 20-40 nm wide glycoprotein layer.

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• Functions of basal lamina-a) They form selectively permeable barrier between adjacent

tissues in some casesb) They have mechanical functions, forming anchoring

intermediaries between epithelial & connective tissues, assisting to stabilize & orient the tissue layers

c) Changes in thickness of basal lamina is often associated with pathological conditions as in thickening of the glomerular membrane in glomerulo-nephritis & diabetes.

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Stratum Basale:

• Cuboidal or columnar cells adjacent to basement membrane• Ability to divide ( mitotic division)• According to orbana) Serrated-heavily packed with tonofilaments which are

adaptations for the attachment.b) Non-serrated-is composed of slowly cycling stem cells which

give rise to population of cells amplified for cell division. Hence called stratum germinativum.

• Least differentiated (contains normal cell organelles)• Characteristic structure –tonofilament and desmosomes

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Stratum Spinosum & Stratum Granulosum :• Spinous layer:1. They are arranged at regular intervals they give the cell prickled

appearance hence also called prickle cell layer.2. Contains fewer cell organelles & more tonofilaments.3. Active in protien synthesis.4. Uppermost cell contain keratinosomes or odland bodies, which are

modified lysosomes. They contain large amount of acid phosphotase an enzyme involved in destruction of organelle membrane.

• Granulosum Layer1. The presence of keratohyaline granules gives it a granular

appearance, hence named so.2. Nuclei shows sign of degeneration & pyknosis.3. Tonofibrils more prominent.4. Still synthesizes protein.

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Stratum Corneum:

• This layer is keratinized and the cells are larger and flatter than granular cells.

• Nucleus and other organelles like mitochondria and ribosomes disappear.

• Keratinized VS. Non Keratinized • The Stratum Granulosum and Stratum Corneum are absent in

the non keratinized epithelium• Ortho VS. Para Keratinized Epithelia• The presence and absence of the nucleii in the Stratum Corneum

determines Ortho and Para keratinized epithelium.

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Inter-cellular Junctions:-

• Types:1. Occluding (tight) junctions (zonula occludens)

2. Adhesive junctionsa. Cell-to-cell i. Zonula adherens ii. Macula adherens (desmosorne)b. Cell-to-matrix i. Focal adhesions ii. Hemidesmosomes

3. Communicating (gap) junctions

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Occluding junctions:

• The transmembrane adhesive proteins, which include occludin, members of the claudin family, and in some tissues, junctional adhesion molecule (JAM), interact homotypically with the same proteins on the adjacent cell.

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Adhesive junction:

• Hold cells together or anchor cells to the extracellular matrix. In contrast to tight junction the intercellular space in cell-cell adhesive junction is maintained at approximately 20 nm.

• Adhesive junctions are also important in cellular signaling• In cell-cell adhesive junctions, the principal

transmembrane proteins are members of the cadherin family.

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• Cadherins are calcium ion-dependent proteins that interact homotypically with cadherins on the adjacent cell.

• The cytoplasmic adapter proteins are members of catenin family.

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Desmosome:• In the Desmosome the

cadherins are desmoglein and desmocollin. The interaction of these transmembrane proteins with those from the adjacent cell results in a dense line in the middle of the intercellular space at the desmosome.

• The catenins are desmoplakin and plakoglobin, which form an electron- dense plaque on the cytoplasmic side of the desmosome.

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Cell matrix junctions:-

• Have a structural organization similar to that of cell-cell adhesive junctions, but they use different molecular components and attach the cell to the extracellular matrix.

• In focal adhesions the transmembrane component is a member of the integrin family of adhesion molecules.

• Integrins are heterodimers of different alpha and beta subunits with specificity for various extracellular matrix molecules.

• Eighteen known alpha subunits and 8 beta subunits occur in 24 different combinations.

• integrin binds to collagen, laminin, fibronectin, and other extracellular matrix proteins

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Hemidesmosome:• The transmembrane adhesive

molecules present in hemidesmosome are the integrin alpha 6, beta 4, which binds specifically to the basal lamina glycoprotein laminin, and collagen XVII (also identified as BPI8O).

• Hemidesmosomes link the cell to the basal lamina, and through additional extracellular molecules, to the rest of the extracellular matrix.

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Gap junctions:

• Transmembrane proteins of the connexin family form aqueous channels between the cytoplasm of adjacent cells.

• Six connexin molecules form a connexon, which has a central channel approximately 2nm diameter.

• The connexons in one cell pair with connexons in the adjacent cell to create a patent channel. Small molecules such as ions and signaling molecules can move readily from one cell to another.

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Cellular organelles variations in different layers of epithelia:-

• Mitochondria are more numerous in deeper strata and

decrease toward the surface of the cell.

• Accordingly, histochemical demonstration of succinic

dehydrogenase, NAD, cytochrome oxidase, and other

mitochondrial enzymes reveals a more active tricarboxylic

cycle in basal and parabasal cells, where the proximity of the

blood supply facilitates energy production through aerobic

glycolysis.

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Epithelium of Gingiva:-• The epithelium covering the

gingiva may be differentiated as follows:

1)Oral epithelium(OE), which faces the oral cavity

2)Oral sulcular epithelium(OSE), which faces the tooth without being in contact with the tooth surface

3)Junctional epithelium(JE) ,which provides the contact between the gingiva and the tooth

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Oral Epithelium:• It covers the oral cavity and the outer surface of marginal gingiva and

attached gingiva,• Represents the keratinized gingiva.• Extends from mucogingival junction to gingival margin.• On average ,the oral oral epithelium is 0.2 to 0.3 mm in thickness.• The degree of gingival keratinization diminishes with age and onset of

menopause.• Palate(most keratized), gingiva, ventral aspect of tongue and

cheek(least keratinized)• K6 and K16, characteristic of highly proliferative epithelia, and K5 and K14, stratification-specific cytokeratins, also are present.• Parakeratinized areas express K19, which is usually absent from

orthokeratinized normal epithelia.

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Sulcular Epithelium:• lines the gingival sulcus• thin, nonkeratized stratified squamous epithelium without rete

pegs and it extends from the coronal limit of the junctional epithelium to the crest of the gingival margin.

• it contains K4, K13 keratins.• It also expresses K19 keratin.• Despite these morphologic and chemical characteristic the

sulcular epithelium has the potential to keratinize if:1)it is reflected & exposed to the oral cavity.2)The bacterial flora of the sulcus is totally eliminated

• These findings suggest that the local irritation of the sulcus prevents sulcular keratinization.

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Junctional Epithelium:• The junctional epithelium consists of a collar like band of

stratified squamous non keratinising epithelium.• According to Glossary of Periodontal terms 2001 Junctional

epithelium “is a unique, non keratinizing, non differentiated tissue which is affixed to tooth structure on one side & oral sulcular epithelium & connective tissue on the other.”

• It is 3 to 4 layers thick in early life, but the number of layers increases with age to 10 to 20 layers.

• It tapers from its coronal end which may be 10 to 29 cells wide to 1 to 2 cells at its apical termination located at the cementoenamel junction in healthy tissues.

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• The length of the junctional epithelium ranges from 0.25 to 1.35 mm.• It is formed by the confluence of the oral epithelium and the reduced

enamel epithelium during tooth eruption.• Produces laminin and play a key role in the adhesion mechanism• The attachment of the junctional epithelium to the tooth surface is

reinforced by gingival fibers which brace the marginal gingiva against the tooth surface.

• Junctional epithelium and the gingival fibers are considered a functional unit referred to as the dentogingival unit.

• Three zones in junctional epithelium--Apical is for germination-Middle is for adhesion-coronal is permeable.

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• Apical zone: - Contains fewer

hemidesmosomes and cell with

germinative characteristics.

• Middle zone:- Area of greatest

attachment having large numbers of

hemidesmosomes

• Coronal zone:- Area of greatest

permeability characterized by numerous

intercellular spaces. Some of which

directly open into internal basal lamina.

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• The junctional epithelium is the only gingival epithelium with two distinct basal laminas. It has a basal lamina on each surface.

External basal lamina:• This basal lamina mediates the

attachment of the junctional epithelium to the connective tissue.

Internal Basal Lamina• This attaches the junctional epithelium to

the tooth surface.The 2 zones of basal lamina • Lamina lucida (electron lucent zone) & • The lamina densa (electron dense zone).

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• Internal Basal Lamina:

• It lacks most of the common basement membrane components such as collagen types IV and VII, most laminin isoforms, perlecan, and a lamina fibroreticularis (Hormia et al., 2001).

• Laminin-5, however, appears to be expressed in the internal basal lamina (Oksonen et al., 2001).

• External basal lamina :• contains collagen type IV, heparan sulfate proteoglycan,

laminin, and fibronectin.• Kobayashi et al. described a third lamina, the sublamina lucida

(120 ± 20A), between the tooth and lamina densa.

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Antimicrobial activity of JE:(1) because of rapid cell division(2) and funnelling of junctional epithelial

cells towards the sulcus hinder bacterial colonization. Laterally, the (external) basement membrane forms an effective barrier against invading microbes

(3) Active antimicrobial substances are produced in junctional epithelial cells. These include defensins and lysosomal enzymes

(4) Epithelial cells activated by microbial substances secrete chemokines,

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Modes of attachment of Junctional epithelium:

GOTTLIEB IN 1921• Concluded that there is no such space. Rather, the gingiva

forms an organic union with the enamel and is firmly bound to it, and he named it as (epithelansatz or epithelial attachement).

ORBAN 1944• Incorporated the views of Meyer, Becks, and Weski by

stating that, the separation of the epithelial attachment cells from the tooth surface involved preparatory degenerative changes in the epithelium.

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WAERHAUG 1952• He described the gingiva as being separated from the tooth

by a capillary space, forming an epithelial cuff. • This cuff was believed to be weakly adherent to the tooth, and

could be displaced from the tooth surface and then replaced against it without diminishing the strength of the adhesion.

STERN 1962• First demonstrated the ultra structure of the ameloblast

enamel junction (the dentogingival junction) of rat incisor which consists of a basal lamina and hemidesmosomes, and that the basal lamina has components namely lamina lucida and lamina densa

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Turnover of JE cells & Development of Gingival sulcus:

• The junctional epithelium(JE) is formed by the joining of the oral epithelium(OE) and the reduced enamel epithelium(REE).The arrows indicate the coronal movement of the regenerating epithelial cells which multiply more rapidly in the JE then in OE

Demetriou and Ramfjord, 1972

• The migrating daughter cells provide a continuous attachment to the tooth surface.

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Difference between the three epithelium:-

• There are three distinct difference between the three epithelia in respect to the junctional epithelium:-

1. The size of the cells in the junctional epithelium is, relative to the tissue volume i.e. larger than in the oral epithelium.

2. The intercellular space in junctional epithelium is, relative to tissue volume i.e. wider than the oral epithelium.

3. The no. of desmosomes are smaller in the junctional epithelium than in the oral epiuthelium

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The dentogingival unit:• The dentogingival unit comprises of the

junctional epithelium, the connective tissue and the gingival fibres.

• A term frequently used to describe the dimensions of the soft tissues that face the teeth is the biologic width of the soft tissue attachment.

(1) the biologic width of the attachment varied between about 2.5 mm in the normal case and 1.8 mm in the advanced disease case, and

(2) the most variable part of the attachment was the length of the epithelial attachment (junctional epithelium).

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Gingival Fluid (Sulcular Fluid)

• The gingival sulcus contains a fluid that seeps into it from the gingival connective tissue through the thin sulcular epithelium.

• The gingival fluid is believed to:1) cleanse material from the sulcus.2) contain plasma proteins that may improve adhesion of the epithelium to the tooth.3) possess antimicrobial properties.4) exert antibody activity to defend the gingiva.

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Gingival connective tissue:-• The major components of the gingival connective tissue are

collagen fibers (about 60% by volume), fibroblasts (5%), vessels, nerves, and matrix (about 35%).

• The connective tissue of the gingiva is known as the lamina propria and consists of two layers: (1) a papillary layer subjacent to the epithelium, which consists of papillary projections between the epithelial rete pegs, and (2) a reticular layer contiguous with the periosteum of the alveolar bone.

• The components of the gingival connective tissue can be divided into as matrix component(or ground substance) and the fibre component.

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• The ground substance fills the space between fibers and cells, is amorphous, and has a high content of water.

• It is composed of proteoglycans, mainly hyaluronic acid and chondroitin sulfate, and glycoproteins, mainly fibronectin, osteonectin.

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Connective tissue fibres:

• The three types of connective tissue fibers are collagen, reticular,oxytalan and elastic.

• Collagen type I forms the bulk of the lamina propria and provides the tensile strength to the gingival tissue.

• The elastic fiber system is composed of oxytalan, elaunin.• Oxylatan are scare in gingiva but numerous in the PDL.• Elastin fibers distributed among collagen fibers

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Gingival fibres:• The connective tissue of the marginal gingiva is densely

collagenous containing a prominent system of collagen fibre bundle called the gingival fibres.

• They consist of type I collagen.• The gingival fibers are arranged in five groups: dentogingival,

circular, transseptal, semicircular and transgingival.

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Blood & Lymphatic supply:•Three major sources of gingival blood supply are:-1.Supraperiosteal arterioles.2.Vessels of PDL.3.Arterioles

•Labial & lingual surface of gingiva of mandibular incisors by-Submental lymph node.•Palatal gingiva-Deep cervical lymph node.•Buccal of maxillary and buccal & lingual on mandibular molar region –Submandibular lymph node.

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Nerve supply:

• Branches of trigeminal nerve.a) Labial aspect of maxillary incisors,canines & premolars-

Superior labial branches from infraorbital nerve.b) Buccal gingiva of maxilla-Posterior superior alveolar nerve.c) Palatal gingiva-Greater palatine nerve.d) Lingual gingiva in mandible-Lingual nerve.e) Buccal gingiva-Inferior alveolar nerve.

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Clinical features of healthy gingiva:

• Colour: • Size:

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• Contour: • Shape:

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• Consistency: • Surface texture:

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• Position:

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Gingiva in disease:

• The most widely accepted classification of periodontal diseases is that developed and presented at the 1999 International Workshop for the Classification of Periodontal Diseases.

• This is the basis for clinicians to diagnose lesions of the gingival and periodontal tissues and to clarify the disease status of patients.

• Gingivitis now has the subcategories of dental plaque-induced gingival disease and non-plaque-induced gingival disease.

• The following classification was given by Holmstrup P: Ann Periodontol 4:20, 1999; and Mariotti A: Ann Periodontol 4:7, 1999.

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• Dental Plaque-Induced Gingival DiseasesI. Gingivitis associated with dental plaque onlyA. Without local contributing factorsB. With local contributing factors II. Gingival diseases modified by systemic factorsA. Associated with endocrine system1. Puberty-associated gingivitis2. Menstrual cycle-associated gingivitis3. Pregnancy associateda. Gingivitisb. Pyogenic granuloma4. Diabetes mellitus-associated gingivitisB. Associated with blood dyscrasias1. Leukemia-associated gingivitis2. Other

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III. Gingival diseases modified by medicationsA. Drug-influenced gingival diseases

1. Drug-influenced gingival enlargements2. Drug-influenced gingivitis

a. Oral contraceptive-associated gingivitis

b. OtherIV. Gingival diseases modified by malnutrition

A. Ascorbic acid deficiency gingivitisB. Other

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• Non—Plaque-Induced Gingival LesionsI. Gingival diseases of specific bacterial originA. Neisseria gonorrhoeaeB. Treponema pallidumC. Streptococcus speciesD. OtherII. Gingival diseases of viral originA. Herpesvirus infections1. Primary herpetic gingivostomatitis2. Recurrent oral herpes3. Varicella zosterB. Other

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III. Gingival diseases of fungal originA. Candida species infections: generalized gingival

candidiasisB. Linear gingival erythemaC. HistoplasmosisD. Other

IV. Gingival lesions of genetic originA. Hereditary gingival fibromatosisB. Other

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V. Gingival manifestations of systemic conditionsA. Mucocutaneous lesions

1. Lichen planus2. Pemphigoid3. Pemphigus vulgaris4. Erythema multiforme5. Lupus erythematosus6. Drug induced7. Other

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B. Allergic reactions1. Dental restorative materialsa. Mercuryb. Nickelc. Acrylicd. Other2. Reactions attributable to:a. Toothpastes or dentifricesb. Mouth rinses or mouthwashesc. Chewing gum additivesd. Foods and additives3. Other

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VI. Traumatic lesions (factitious, iatrogenic, or accidental)A. Chemical injuryB. Physical injuryC. Thermal injury

VII. Foreign body reactionsVIII. Not otherwise specified

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Bibliography:

• Carranza’s clinical periodontology 10th edition.• Clinical periodontology and implantology, Jan lindhe, 4th

edition.• Orban’s Oral histology, 12th edition

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