Rationale of endodontic treatment

FISH ZONE

1. Rationale of endodontic treatment

2. Complete debridement of root canal system followed by 3D obturation.

3. Focal infection It is localized or generalized infection caused by dissemination of microorganism or toxic products from a focus of infection.

4. Mechanism of focal Infection Metastasis of microorganism from infected focus Carrying toxins or toxic by-product through blood stream and lymphatic channels to site of reaction.

5. Portal For Entry of Micro Organism Dental caries Open dentinal tubules Accessory and lateral canals Defective restoration

6. Inflammation Local response of living tissue to injury. Signs of inflammation: Rubor (redness) Tumor(swelling) Color Dolor (pain) Function lasea (loss of function)

7. Types of Inflammation

8. Pulp Tissue Changes Following Inflammation Degenerative changes : Fibrous Resorptive Calcific

9. Suppuration is another form of degeneration which is due to injury to polymorphonuclear cells. It causes release of proteolytic enzymes with resulting liquefaction of dead tissues thus leading to formation of pus or suppuration .

10. Proliferative changes: Produced by irritants Strong enough to produce degeneration or destruction Principal cells : Fibroblast (cellular fibrous tissue)

11. Inflammatory cells: Neutrophils:

12. Inflammatory cells: Eosinophils:

13. Inflammatory cells: Macrophages:

14. Inflammatory cells: Lymphocytes: T lymphocytes B-lymphocytes T helper cells- present in acute phase of lesion T suppressor- predominate in later stage prevent rapid expansion of lesion. On getting signals from antigen and T helper cells they transform into plasma cells and secrete antibodies.

15. Non specific mediators of periradicular lesions : Cell derived Plasma derived mediators Effector molecules Neuropeptides Cytokines Lysosomal enzymes Platelet activating factor Prostaglandins Fibrinolytic system Complement system Kinin system

16. ENDODONTIC IMPLICATION “FISH” established foci of infection and found 4 well defined zones of reaction Zone of infection Zone of contamination Zone of irritation Zone of stimulation

17. Zone of infection Polymorphnuclear leukocytes Present in the center Micro-organism along with necrotic cells present Destructive components are released from phagocytes.

18. Zone of contamination Round cell infiltration Cellular destruction (bacteria & toxins discharged from central zone). Bone destruction Lymphocytes present

19. Zone of irritation Toxins in this area more diluted Collagen fibers digested by phagocytic cells, macrophages. Osteoclast leads to bone destruction Histologically it represent preparation for repair.

20. Zone of stimulation Characterized by fibroblast, osteoblast. Built as a wall of defense around zone of irritation Act as a scaffolding on which osteoblast built new bone.

21. Kronfeld’s mountain pass theory Applied Fish concept so as to explain the tissue reaction in and around granulomatous area . Zone A: Bacteria in infected root canal with invaders entrenched behind high and in accessible mountains and foramina serving mountain passes.

22. Zone B: Proliferative changes of granuloma represents a mobilized army defending the periapex (plains) from bacteria (invaders). Few bacteria (invaders) enter the periapex (plains) through the mountain pass they destroy leukocytes (defenders). This mass attack result in major battle analogous to acute inflammation.

23. Zone C: Complete elimination of invaders from mountain entrenchment will eliminate the need for defense forces in the plains . Once this is accomplished the defending army of leukocytes withdraws the local destruction and the environment returns to its normal pattern.

24. summary Focal infection Pulp Tissue Changes Following Inflammation FISH ” zones Zone of infection Zone of contamination Zone of irritation Zone of stimulation Kronfeld’s mountain pass theory