ATHUL PERIO. Defence mechanism of gingiva

Dental

1. DEFENCE MECHANISM OF THE GINGIVA SUBMITTED BY, ATHUL K V FINAL YEAR PART 1 180021964 GUIDED BY; Dr. ARUN MARADI Dr. ajey bhat Dr. renjith madhavan Dr. SUNEETHI MARGARET DEY

2. CONTENTS INTRODUCTION GINGIVAL CREVICULAR FLUID SALIVA JUNCTIONAL EPITHELIUM LEUKOCYTES CONCLUSION REFERENCE

3. INTRODUCTION Defence is resisting an attack . T here are numerous protective mechanisms that work in the oral cavity against various insults. Gingiva is constantly subjected to a wide array of mechanical and bacterial aggressions.

4. In gingiva these challenges are maintained by; 1. Gingival crevicular fluid 2. Saliva 3. Junctional epithelium 4. Leukocytes

5. GINGIVAL CREVICULAR FLUID INTRODUCTION The presence of sulcular fluid, or gingival crevicular fluid ( GCF ), has been known since the 19 th century, B ut its composition and its possible role in oral defence mechanisms were elucidated by the pioneering work of Waerhaug and Brill and Krasse during the 1950 s. The latter investigators introduced filter paper into the gingival sulci of dogs.

6. This indicated the passage of fluid from the bloodstream through the tissues and the exiting of fluid via the gingival sulcus . That had previously been injected intramuscularly with fluoresceine,within 3 minutes the fluorescent material was discovered on the paper strips.

7. COMPOSITION MICROBIAL PLAQUE Endotoxins (LPS) Enzymes(acid phosphatase,alkaline phosphatase ) Metabolic end products(Prostaglandin like product, Trypsin like enzyme) HOST CELLS Leukocytic enzymes Lactoferrin Lysozyme Myeloperoxidase HOST FACTORS (Immune response) Immunoglobulins ( IgG,IgA,IgM ) Complement factors Eicosanoids Cytokines(IL-1) DAMAGED HOST TISSUES Collagens Proteoglycans Matrix proteins ( Osteonectin )

8. METHODS OF COLLECTION GCF is little in amount to be obtained from the sulcus , so that numerous methods were tried ; 1) Absorbing paper strips are placed within the sulcus ( intrasulcular ) or at its entrance ( extrasulcular ).

9. 2) Twisted threads placed around and into the sulcus . 3) Micropipette which permit the absorption of fluid by capillarity .

10. 4) Intracrevicular washings can be used to study CF from clinically normal gingiva.

11. AMOUNT AND MEASUREMENT 1. Fluid can be collected on a paper strip, the wetted area could be stained with ninhydrin then measured planimetrically . 2. Fluid could be measured electronically using electronic transducer ( Periotron ) . Electronic machine for measuring the amount of fluid collected on filter paper

12. CLINICAL SIGNIFICANCE • GCF is an inflammatory exudate , its presence in clinically normal sulci , can be explained microscopically due to presence of inflammation. • The amount of GCF is greater when inflammation is present and proportional to severity of inflammation.

13. • GCF production is not increased by trauma from occlusion It is increased by the mastication of coarse foods, tooth brushing and gingival massage, ovulation, hormonal contraceptives, prosthetic appliances, circadian periodicity, periodontal therapy and smoking.

14. a) Circadian periodicity : •There is gradual increase in GCF amount from 6 am to 10 pm and a decrease afterwards. b) Sex hormones : •Female sex hormones increase GCF flow, because they enhance vascular permeability. •Pregnancy, ovulation and hormonal contraceptives increase GCF . .

15. c) Mechanical stimulation : •Chewing and vigorous gingival brushing stimulate the flow of GCF . •Even minor stimulation represented by intrasulcular placement of paper strips increases the production of fluid

16. d) Smoking : • Smoking produces an immediate transient but marked increase in GCF flow. e) Periodontal therapy : • There is an increase in GCF production during the healing period after periodontal surgery. 

17. FUNCTIONS OF GCF Clearance of deadcells and bacterial molecule from the gingival sulcus Exert antibacterial and antibody activity The plasmaproteins improves the adhesion of epithelium to the tooth

18. DRUGS IN GINGIVAL CREVICULAR FLUID : • Drugs that are excreted through the GCF may be used advantageously in periodontal therapy. • Tetracycline are excreted Through GCF .

19. • Metronidazole is another antibiotic that has been detected in human GCF

20. SALIVA INTRODUCTION Saliva maintains the oral tissues in a physiologic state. Saliva exerts a major influence on plaque by mechanically cleansing the exposed oral surfaces, by buffering acids produced by bacteria, and by controlling bacterial activity.

21. COMPOSITION ■ Saliva contains inorganic and organic factors which influence bacteria and their products. Antibacterial Factors Inorganic factors are ions and gases, bicarbonate, sodium, potassium, phosphates, calcium, fluorides, ammonia, and carbon dioxide.

22. Organic factors are: lysozymes, lactoferrin, myeloperoxidase, lactoperoxidase Agglutinins such as glycoproteins, mucins, fibronectins. Antibodies

23. Antibodies Saliva contains antibodies (Abs) which react with indigenous oral bacterial species. The most preponderant immunoglobulin ( Ig ) is IgA.Saliva also contains IgG and IgM . Salivary Abs are synthesized locally.

24. Many bacteria found in saliva have been shown to be coated with IgA, and the bacterial deposits on teeth contain both IgA and IgG. IgA inhibits the attachment of oral Streptococcus species

25. Enzymes The major enzyme is parotid amylase . Other enzymes increased in periodontal disease, e.g., hyaluronidase , lipase, p gluronidase , and chondroitin sulfatase, amino acid decarboxylases, catalase, peroxidase, and collagenase.

26. Proteolytic enzymes in saliva are generated by the host and oral bacteria . Buffers Bicarbonate - carbonic acid system is the most important salivary buffer.

27. This buffer system maintains the physiologic hydrogen ion concentration (pH) at the mucosal epithelial cell surface and the tooth surface Coagulation Factors Saliva contains factors VIII, IX, and X, plasma thromboplastin antecedent (PTA) and Hageman factor. These factor protect wounds from bacterial invasion.

28. Cells Saliva Contains desquamated cells and all forms of leukocytes, mostly PMNs.These cells vary from person to person. Leukocytes reach the oral cavity by migrating through the gingival sulcus .

29. ROLE oF SALIVA IN PERIODONTAL PATHOLOGY Saliva exerts a major influence on plaque initiation, maturation, and metabolism. Salivary flow and composition also influence calculus formation, periodontal disease, and caries.

30. The removal of the salivary glands in experimental animals increases the incidence of dental caries and periodontal disease and delays wound healing In humans, decrease in salivary gland secretion resulting in a condition called xerostomia.

31. Xerostomia may result from a variety of factors, among them sialolithiasis, sarcoidosis, Sjogren’s syndrome, Mikulicz’s disease, irradiation and surgical removal of the salivary glands. Xerostomia is associated with an increase in inflammatory gingival diseases, dental caries, and rapid tooth destruction associated with cervical or cemental caries

32. ROLE OF SALIVA IN ORAL HEALTH Saliva protects the oral cavity by its functions which are; Lubrication via glycoproteins and mucoids . Physical protection via glycoproteins and mucoids . Cleansing via physical flow which clear the debris and bacteria.

33. JUNCTIONAL EPITHELIUM Junctional epithelium is the stratified non-keratinizing   epithelium that surrounds the tooth like collar with a cross section resembling a thin wedge. The epithelium of gingiva which gets attached to the tooth is called junctional or attachment epithelium

34. The junctional epithelium exhibits several unique structural and functional features that contribute to preventing pathogenic microbial flora from colonizing the subgingival tooth surface.

35. • First , junctional epithelium is firmly attached to the tooth surface , forming an epithelial barrier against plaque. • Second , it allows access of gingival fluid inflammatory cells and components of the immunologic host defense to the gingival margin.

36. Third , junctional epithelial cells exhibit rapid turnover which contributes to the host parasite equilibrium and rapid repair of damaged tissue

37. LEUKOCYTES The saliva contains all forms of leukocytes, of which the principal cells are PMNs . The number of PMNs varies from person to person at different times of the day is increased in gingivitis.

38. PMNs reach the oral cavity by migrating through the lining of the gingival sulcus. Living PMNs in saliva are sometimes referred to as orogranulocytes , and their rate of migration into the oral cavity is termed the orogranulocytic migratory rate.

39. CONCLUSION The oral cavity is well equipped to counterattack any adverse condition that may harm the gingiva . While the innate immunity acts primarily against any foreign invades, the specific immunity takes a more complex targeted approach to protect the gingiva . Right from its superficial epithelial layer to the innermost connective tissue, there is a line of defense that acts in harmony with other oral structures to maintain homeostasis to revert any imbalance that would otherwise shift to the equilibrium to the diseased state.

40. REFERENCE Newman and Currenza’s,clinical periodontology, third edition Pathogenesis of periodontitis . Jan Lindhe , Niklaus P.Lang , Thorlid Karring . Sembulingam K and Sembulingam P (2010). Essentials of medical physiology . 5th ed.

41. THANK YOU