Gingiva

Gingiva

1. DEPARTMENT OF PERIODONTICS TOPIC- GINGIVA Name-PARTHA PROTIM SINGHA (BDS FINAL YEAR )  

2. CONTENTS Introduction Macroscopic Features Marginal Gingiva Attached Gingiva Interdental Gingiva Microscopic Features Cells Fibers Blood and Lymphaties supply Never supply to Gingiva

3. INTRODUCTION INTRODUCTION The Gingiva is the part of oral mucosa that cover the alneolar proceses of the Jaw and surrounds the neck of the teeth.

4. MACROSOPIC FEATURES Anatomically,the gingiva is divided into three parts, it includes: Marginal. Attached. Interdental gingival.   Marginal Gingiva /Free Gingiva /Unattached Gingiva The marginal or unattached gingival is the terminal edge or border of the gingival surrounding the teeth in collar-like fashion. In about 50% of cases it is demarcated from the adjacent, attached gingival by shallow linear depression, the free gingival groove. Usually about 1mm wide, it forms the soft tissue wall of the gingival sulcus . It may be separated from the tooth surface with a periodontal probe.

5. Gingival Sulcus The gingival sulcus is defined as the space or shallow crevice between the tooth and the free gingival. The tooth bounded by the surface of the tooth on one side and the epithelial lining the free margin of the gingiva on other. It is V-shape and barely permits the entrance of a periodontal probe. Under absolutely normal or ideal condition, the depth of the gingival sulcus is or about 0 mm. In clinically healthy gingiva in humans a sulcus of some depth can be found. The depth of this sulcus is 1.8 mm. The clinical maneuver used to determine the depth of the sulcus is the introduction of a metallic instrument –the periodontal probe- and the estimation of the distance it penetrates. The histologic depth of a sulcus need to be exactly equal to the depth of penetration of periodontal probe then so called probing depth of a clinically normal gingival sulcus in human is 2 to 3 mm.

6. Attached Gingiva The attached gingiva is continuous with the marginal gingival. It is firm, resillent and tightly bounded to the underlying periosteum of the alveolar bone. The facial aspect of the attached gingival extend to the relatively loose and movable alveolar mucosa, from which it is demarcated by the mucogingival junction. The width of attached gingiva on the facial aspect differ indifferent areas of the mouth. It is generally greater in incisor region (3.5 to 4.5 mm in maxilla and 3.3 to 3.9 in mandible) and less in posterior segment . Least width in 1 st premolar area (1.9 mm in maxilla and 1.8 mm in mandisble ) The width of attached gingiva increase with age and in supraerupted teeth.

7. Methods to measure the width of attached gingiva :- There are four different method used to find the width of attached gingival. Measurement approach :- In this method first the pocket depth or the sulcus depth is measured and then the total width of gingiva is measured, i.e. from gingival margin to mucogingival line. Thus by subtracting these two measurements, we get the attached gingiva can acquire. Total gingival width-pocket depth= width of attached gingival.

8. By using Schiller’s potassium iodide solution :- It is similar to measurement approach. Potassium iodide (KI) solution only stains the keratinized epithelium, i.e. marginal gingiva , attached gingiva and interdental papilla. After application of this solution, the total width of gingiva is measured that is from gingival margin to mucogingival line and later the sulcus depth or pocket depth is measured. Then by subtracting the total gingival width from pocket depth, we get the width of attached gingival. Stained total gingival width- pocket depth = width of attached gingiva .

9. Tension test:- This is done by stretching the lip or cheek to demarcate the mucogingival line and to see for any movement of the free gingival margin. And if the free gingiva margin moves during stretching of lips then the attached gingiva is considered to be inadequate. Roll test :- It is done by pushing the adjacent mucosa coronally with a dull instrument. If the gingiva moves with the instrument then the width od attached gingiva is considered inadequate. In adequate width, the gingiva dose not move because the attached gingiva is firmly attached to the underlying bone.

10. Interdental Gingiva The interdental gingiva occupies the embrasure which is the inter proximal space beneath the area of tooth contact. The interdental gingiva can be pyramidal or have a “ col ” shape. In pyramidal the tip of one papilla is located immediately beneath the contact point. The lather presents a valley like depression that connect a facial and lingual papilla and conforms to the shape of the interproximal contact. The shape of the gingiva in given interdental shape depends on the contact point between the two adjoining teeth and the presence or absence of some degree of the recession If a diastema is present the gingiva is firmly bound over the interdental bone and forms a smooth rounded surface without interdental papilla.

11. MICROSCOPIC FEATURES Gingiva consist of a central core of connective tissue covered by stratified squamous epithelium. Three types of epithelium exist in gingiva :- The oral or outer epithelium/keratinized epithelium The sulcular epithelium The junction epithelium/non-keratinized epithelium Keratinized Epithelium:- In the keratinized epithelium the principal cell type is Keratinocyte which can synthesis Keratin the process of Keratinization involves a sequence of biochemical and morphological events that occur in a cell as it migrates from the basal layer toward the cell surface. Non-Keratinized Epithelium:- The non-keratinized epithelium contain clear cells, which include melanocytes , Langerhans cells, Merkel cells and lymphocytes.

12. Oral Epithelium Oral epithelium has the following cell layers:- Basal layer (stratum basale or stratum germinativum ). Spinous layer (stratum spinosum ). Granular layer (stratum granulosum ). Keratinized cell layer (stratum corneum ). There are three distinct differences between the oral sulcular epithelium , oral epithelium and the junction epithelium: The size of the cell in the junctional epithelium is relative to the tissue volume , layer than in the oral sulcular epithelium. The intercellular space in the junctional epithelium is comparatively wider than in the oral epithelium. Granular layer which is seen in the oral epithelium is absent in sulcular and junctional epithelium.

13. Morphologic Characteristics of the Different Areas of Gingival Epithelium Oral or Outer epithelium:- It cover the crest and outer surface of the marginal gingiva and the surface of the attached gingiva . It is keratinized oe parakeratinized or combination of both. Keratinization varies in different areas in the following order : palate(most keratinized ), gingiva , ventral aspect of the tongue and cheek (least keratinized ). The keratinized epithelium of the gingival consists of four layers, namely :-

14. Stratum basale :- The cells of basal layer are either cylindrical or cuboidal and are in contact with the basement membrane. The basal layer have ability to divie thatwhy also known as stratum germinativum . When two daughter cells have been formed by cell division, an adjacent ‘older’ basal cell is pused into the spinous cell layer and starts as a keratinocyte , to traverse the epithelium. It takas approximately 1 month for a keratinocyte to reach the outer epithelial surface. The basal cells are separated from connective tissue by a basement membrane. In light microscopy this membrane appear as zone approx 1 micrometer wide and reacts positively to a PAS strain.

15. Immediately beneath the basal cell there is zone called as lamina lucida and beneath this electron dense zone called as lamina densa The epithelial cells facing the lamina lucida contain no electron dense zone called as hemidesmosomes The hemidesmosomes are involves in attachement of epithelium to underline basement membrane Stratum spinosum It consist of large cells with short cytoplasmic processes resembling spine arrange that regular intervals, give the cells a prickled appearence

16. Stratum granulosum Electron dense keratohyalin bodies began to occur ; these granules are believed to be related to the synthesis of keratin. Stratum corneum The soft tissue wall of gingival sulcus is lined coronally with sulcular epithelium extending from gingival margin to the junctional epithelium. The sulcular epithelium resembles the oral epithelium in all respect except that is dose not become fully keratinized. Although it contain keratinocytes ,they do not undergo keratinization

17. Junctional Epithelium Denotes the tissue that joins to the tooth on one side and to the sulcular epithelium and C.T on the other It form the base of sulcus General Structrual Features of Junctional Epithelium It consist of collar like band of stratified squamous non-keratinized epithelium. The length of junctional epithelium ranges from 0.25 to 1.35 mm. Three zone in junctional epithelium is described: Apical for germination Middle for adhesion Coronal or permeable   Non- Keratinocytes or clear cell Non- keratinocytes are melanocytes , langerhans cells, merkel cells and inflammatory cells. They together make up to 10% of the cell population in oral epithelium.  

18. MELANOCYTES:- These are highly specialized dendritic cells of neural crest origin located in the basal and spinous layer of gingival epithelium. It synthesizes melanin pigment They are packed with numerous melanosomes , which contain tyrosinase that hydroxylates tyrosine to dihydroxphenylalanine (DOPA ),which gets converted to melanin. Gingiva , buccal mucosa, hard palate and tougue Langerhans cells They are dendritic cells located among the keratinocytes at all suprabasal levels. They have immunologic function They contain g-specific granules which are rod or flask shaped granules. Found in oral epithelium of normal gingiva and in smaller amounts in sulcular epithelium.

19. Merkel cells Theyare located in the basal cell layer of gingival epithelium. Identified as tactile receptors. Merkel cells are sensory and respond to touch. Contains small membrane bound vesicles in the cytoplasm sometimes situated adjacent to a nerve fiber associated with the cells. Inflammatory cells Commonly seen in the nucleated cell layers. Mostly lymphocytes are seen.  

20. Supra Alveolar Connective tissue The connective tissue supporting the oral epithelium is formed as lamina propria and for descriptive purpose it can be divided into two layer. Superfical papillary layer:-associated with epithelial ridger Deeper reticular layer:-that lies between the papillary layer and underlying structures. The lamina propria consist of cells ,fibers , B.V,embedded in amorphous ground substance CELLS – Fibroblast Macrophage Mast cells inflammatory cells FIBRES – The C.T fibers are produced by fibroblast and can be divided into Collagen fibers oxytalan fibers Reticulin fibers Elastin fibers Collagen types 1 form the bulk of the lamina propria and provide the tensile strength to the gingival tissue Collagen types 2 seen in basement membrane The function of gingival fibers It braces the marginal gingival firmily against the tooth It helps to withstand the forces exected by mastication It units the free gingiva to the root cementum and the adjacent attached gingiva

21. PRINCIPAL GROUP FIBERS Dentogingival fibers They protect the cementum in a fan like conformation towards the crest and outer surface of marginal gingiva . Alveolar gingival fiber They extend from the periorteum of the alveolar crest coronally into the lamina propria .Their function in to attach the gingiva to the alveolar bone. Dentoperiosteal fibers They arise from the cementum near the cementoenamel junction and insert into the periostum of the alveolar bone and protect the periodontal ligament Circular fibers Surrounds the tooth in a cuff or ring like fashion and course through the C.T of marginal and attached gingival. Transseptal fibers Located interproximally , they extend from cementum of one tooth to other there function is to protect the interproximal bone and maintain tooth to tooth contact .

22. Fibers of secondary group Periosteogingival fibers They extend from the periosteum of the alveolar bone to the attached gingiva . They help to attach gingiva to the alveolar bone. Interpapillary fibers Seen in interdental gingiva extending in a facio lingual direction and support the gingival papilla Transgingival fibers They are seen in and around the teeth with in the attached gingiva . They maintain the alignment of teeth in the arch  

23. Intercircular firbers They extend from cementum on distal surface of tooth splaying buccally and lingually around the next tooth and are inserted on the mesial surface. Intergingival fibers They are seen within the attached gingiva adjacent to the basement membrane extending mesiodistally . They provide support and contour for the attached gingiva . Semicircular fibers They extend from the mesial surface of a tooth to the distal surface of the same tooth in a half circle. Oxytalan fibers They are present in all connective tissue structures of the periodontium . The function of these fiber is , yet unknown. Elastin fibers The elastin fibers are only present in connective tissue of the gingiva and periodontal ligament. They are also seen in connective tissue of alveolar mucosa in large number.

24. Blood and lymphatics supply There are three major sources of blood supply to the gingiva Supraperiosteal arterioles:-overlying the alveolar bone along the facial and lingual surfaces several branches to surrounding tissue Vessels of periodontal ligament Arterioles emerging from the crest of interdental septa Lymphatic drainage of the gingiva brings in the lymphatics of the connective tissue papillae

25. Never supply to gingiva Receptor are seen as free ending within papillary layers of lamina propria . The following never structure are present in the connective tissue which are basically a mesh work of terminal argyrophilic fiber which sometimes extend into the epithelium Meissner type tactile corpuscles :- touch receptor Krause type of end bulb :- temperature receptor Fine fibers in the papilla:- pain receptor

26. REFERENCES Carranza’s Clinical Periodontology – 11 th edition Essentials of Clinical Periodontology & Periodontics -by Shantipriya Reddy

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