abfraction

noun

ab·​frac·​tion ab-ˈfrak-shən 

: a mechanism that is postulated to explain loss of tooth enamel and dentin in the part of a tooth between the crown and root in the absence of tooth decay

also : the narrow usually V-shaped area of tooth loss caused by abfraction

Note: Abfraction is postulated to occur when the force generated by occlusion (as during chewing) causes stress to concentrate on certain points of a tooth. This stress results in tooth flexure and leads to the eventual breaking away of hard tissue.