Attrition, Abrasion and Erosion and Their Interactions in Tooth Wear.

Tooth wear involves three processes. Abrasion is a form of three-body wear produced by abrasive components of slurries contacting the teeth (either food or, in modern Western populations, mainly toothpaste). Attrition is a form of two-body wear through tooth-tooth contact. Erosion is demineralization of hard tissue, caused by acidic ingested substances (foods, drinks or medications), by regurgitated gastric acid or by acidic industrial vapours. A further process (abfraction) is said to be caused by occlusal stresses, which might enhance wear in the cervical region by abrasion and/or erosion. A review of the knowledge on these tooth wear processes and their interactions is provided. Both clinical and experimental observations show that, in modern Western populations, individual wear mechanisms rarely act alone but interact with each other. The most important interaction is the potentiation of abrasion by erosive damage to the dental hard tissues ('softening'). This interaction seems to be the major factor in pathological wear of occlusal and cervical surfaces. The available evidence is insufficient to establish whether abfraction is an important contributor to tooth wear in vivo.