1) Acquired tooth pathology 
Abfraction or Theory of Abfraction is a theory explaining the non-carious cervical lesions (NCCL). It suggests that they are caused by flexural forces, usually from cyclic loading; the enamel, especially at the cementoenamel junction (CEJ), undergoes this pattern of destruction by separating the enamel rods. As teeth flex under pressure, the arran...
Wear, or notching, at the neck of a tooth at or below the gum line. Often sensitive and often accompanied by gum recession that is thought to be caused by excessive clenching or grinding.
(ab-frak´shәn) pathological loss of tooth structure owing to biomechanical forces (flexion, compression, or tension) or chemical degradation; it is most visible as V-shaped notches in the cervical area of a tooth.
Type: Term Pronunciation: ab-frak′shŭn Definitions: 1. To break away.