There are three main types of physical tooth wear mechanisms. These include attrition, abrasion, and abfraction.
- Attrition is the physical wearing away of hard dental tissue due to tooth-to-tooth contact with no foreign substance intervening. It can be physiological when it is involved in the normal wear of the premolars and molars (called occlusal wear), or is caused by a malocclusion—or “bad bite”— that damages buccal, lingual, and interproximal tooth surfaces. However, attrition can also be pathological when it is caused by certain habits of the patient, particularly tooth grinding.10
- Abrasion is the wearing away of hard dental tissue by mechanical processes involving foreign objects, or substances repeatedly introduced in the mouth and contacting the teeth.9 Previously, the definition of abrasion assumed that all abrasion is pathological, but because abrasion can be caused by factors that are beneficial, the word pathological is no longer always associated with abrasion.2 Etiological factors include oral hygiene habits, such as using toothpaste (the major abrasive agent in Western populations), brushing teeth in a way that might be too hard or too long, or excessive flossing; personal habits, such as frequently putting foreign objects, such as a pen, in the mouth; and occupational exposure to abrasive particles.11-15 A special form of abrasion is from demastication, the wear that comes from chewing food.11
- Abfraction occurs as a result of shear stress in the cemento-enamel juncture of the tooth, leading to tooth flexure that causes tiny fractures in enamel and dentin. Stress that leads to tooth flexure can be caused by chewing or by tooth grinding.11,15 These areas of wear and tooth loss typically occur at the cervical region on the tooth and are more commonly now referred to as non-carious-cervical lesions or NCCLs.