Age changes in enamel and dentin tissues

Age changes

1. AGE CHANGES in ENAMEL,DENTIN & PULP L. Sai Sindhuja Junior Resident Dept of Conservative dentistry & Endodontics

2. CONTENTS AGING : Definition Theories AGE RELATED CHANGES IN : Enamel Dentin Pulp CLINICAL CONSIDERATIONS

3. INTRODUCTION Aging is a continuous, detrimental and innate phenomenon. Time related process Aging should not be confused with senescence

4. THEORIES OF AGING CONCEPT OF FREE RADICALS ( HARMAN IN 1956 )

5. IDEA OF DNA DAMAGE ( LEO SZILARD IN 1959 )

6. IDEA OF TELOMERES ( WATSON IN 1972 )

7. DRAWBACK OF THEORIES Cause for aging or is the result of aging

8. AGE CHANGES IN ENAMEL Incapable of regeneration - Attrition - Erosion - Abrasion

9. Color is determined by the differences in the translucency of the enamel Yellow color : dentin is visible Grey color : opaque enamel Translucency increases with age causing teeth to be yellower. Loss of enamel rods alters the light reflection of enamel. DISCOLORATION AND INCREASED TRANSLUCENCY ATION

10. Loss of perikymata gradually Localized increase of certain elements such as nitrogen and fluorine found in superficial enamel layers of older teeth Resistance to decay may be increased Reduced permeability of older teeth to fluid

11. Normally enamel is semipermeable With age there is reduced in permeability

12. AGE CHANGES IN DENTIN The two most important changes are : i ) increase in the thickness of dentin ii) increased sclerosis or obliteration of dentinal tubules

13. Interlinked with functional demands placed on dentin

14. REPARATIVE DENTIN & REACTIONARY DENTIN Stimulus Odontoblasts die Odontoblasts survive Stem cells from pulp differentiate to form odontoblast Reactionary or regenerative dentin Reparative dentin Strong Weak

15. DEAD TRACTS Odontoblast process disintegrate Empty tubules are filled with air Black in transmitted light White in reflected light

16. SCLEROTIC DENTIN or transparent dentin Gradually tubule lumen is obliterated with mineral Refractive indices are equalized, and such areas become transparent. Observed in older age especially in roots

17. Harder than normal dentin Elastic properties were not altered Fracture toughness was reduced Crystals were smaller than those present in normal dentin

18. DECREASE IN PERMEABILITY

19. AGE CHANGES IN PULP

20. CELL CHANGES Decrease in size and number of cytoplasmic organelles. The fibroblasts in the aging pulp exhibit less perinuclear cytoplasm and possess long, thin cytoplasmic processes. The intracellular organelles are reduced in number and size

21. FIBROSIS Accumulations of both diffuse fibrillar components as well as bundles of collagen fibers . Increase in fibers in the pulp organ is gradual and is generalized throughout the organ.

22. VASCULAR CHANGES Blood flow decreases with age. Decrease in the number of blood vessels. Atherosclerotic plaques within in pulpal vessels .

23. Outer diameter of vessel walls becomes greater Also calcifications are found that surround vessels. Most often in the region near the apical foramen.

24. PULP STONES / DENTICLES Pulp stones, or denticles, are nodular, calcified masses appearing in either or both the coronal and root portions of the pulp organ.

25. Pulp stones are classified, according to their structure

26. TRUE DENTICLES

27. FALSE DENTICLES

28. Depending on their relation to the dentin of the tooth.

29. DIFFUSE CALCIFICATIONS Diffuse calcifications appear as irregular calcific deposits in the pulp tissue, usually following collagenous fiber bundles or blood vessels. Sometimes they develop into larger masses but usually persist as fine calcified spicules.

30. Diffuse calcifications are usually found in the root canal and less often in the coronal area, whereas denticles are seen more frequently in the coronal pulp.

31. CLINICAL CONSIDERATIONS Exposure of dentin leads to pain like sensation called sensitivity Surface enamel becomes harder due to fluoride uptake from saliva Sclerotic dentin prevents caries progression Pulpal calcifications interfere with root canal procedures Pulp chamber size and variation in shape must be taken into consideration

32. REFERENCES Orban’s oral histology and embryology, 13 th edition Tencate’s oral histology and development structure and function, 8 th edition.