# The abnormal loss of tooth structure due to non-masticatory physical friction is referred to as: A. Erosion B. Abfraction C. Attrition D. Abrasion The correct answer is D. Abrasion. Types of abrasion: 1. Toothbrush abrasion: most often results in V-shaped wedges at the cervical margin in the canine and premolar areas. It is caused by the use of a hard toothbrush and/or a horizontal brushing stroke and/or a gritty dentifrice. 2. Occlusal abrasion: results in flattened cusps on all posterior teeth and worn incisal edges. It results from the chewing or biting of hard foods or objects and chewing tobacco. - Attrition is the wearing away of enamel and dentin due to the normal function or most commonly, due to the excessive grinding or gritting together of teeth by the patient (referred to as bruxism). The most noticeable effects of attrition are polished facets, flat incisal edges, discolored surfaces of the teeth and exposed dentin. Facets usually devel...