The loss of tooth tissue without decay occurs through three different mechanisms, and their treatments are entirely different. Attrition: This is mechanical wear caused by contact between teeth; an example is the flattened chewing surfaces of teeth in bruxism (teeth grinding) patients. Abrasion: This is wear caused by friction against a foreign substance; examples include horizontal grooves on tooth surfaces resulting from brushing teeth too hard horizontally with a stiff-bristled brush or biting on a pipette. Abfraction: This is the crackling and shedding of enamel prisms due to bending and flexing forces in the neck region (gum margin) of the tooth during chewing, caused by malocclusion; deep “V”-shaped notches form in the tooth neck.