1. TYPES OF LESIONS INVOLVED
IN TOOTH DESTRUCTION
1. Dental Caries
2. Wear and Abrasion
3. Attrition
4. Erosion
5. Fracture
6. Localized non-hereditary enamel hypoplasia
7. discoloration

2. Dental Caries
It is an infectious microbial disease that results in breakdown or softening of the enamel and dentin.
This destructive process progresses more rapidly in dentin than in enamel to create an undermining effect, hence the term “cavity”.

3. 2. Wear and Abrasion Wear:
Results from rubbing teeth against each other or from chewing “gritty” food.

4. Abrasion:
abnormal mechanical processes involving foreign objects or substances repeatedly
introduced in the mouth and contacting the teeth.

5. 3. Attrition
physiological wearing away of dental hard tissue as a result of
tooth-to-tooth contact with no foreign substance intervening.

6. 4. Erosion
A chemo mechanical loss of hard tooth tissues.
It is caused by chemical etching away by acid and/or chelation without bacterial involvement

7. 5. Fracture:
Due to :
Accidental blow or sports injury.
Heavy masticatory forces.
Biting on hard object.

8. 6. Localized non-hereditary enamel hypoplasia:
It is a defect in enamel due to improper matrix formation caused by injury to ameloblasts.

9. Lesions range from isolated pits to wide spread linear defects.
They have different colors from the surrounding enamel

10. Causes:
Systemic disorders: Due to nutritional deficiencies
Localized disorders: resulting from periapical infections or traumatic intrusion of the preceding deciduous tooth.
Fluorides: excessive amounts poison the ameloblasts and disturb their activities.

11. 7. Discoloration
Definition: Deviation from the normal color. It can affect one tooth or it can be generalized.
Causes:
A- Extrinsic: due to
surface staining, calculus or any other surface deposits.

12. B- Intrinsic: due to
Enamel hypoplasia
Hypo-calcification.
disintegration of the dentinal tubules content.

13. Tetracycline administered during the formation of dentin or enamel
Pulpal necrosis, in which the disintegration products diffuse through the dentinal tubules