Tooth wear (also termed non-carious tooth substance loss) refers to loss of tooth substance by means other than dental caries or dental trauma. There are four types of tooth wear:
Acid erosion – loss of tooth substance caused by chemical dissolution by acids, unrelated to dental caries. Erosion may occur with excessive consumption of acidic foods and drinks, or medical conditions involving repeated regurgitation and reflux of gastric acid (e.g. gastro-esophageal reflux disease, bulimia, or alcoholism).
Attrition – loss of tooth substance caused by physical tooth-to-tooth contact, such as may occur in bruxism. A degree of attrition is normal, especially in elderly individuals.
Abrasion – loss of tooth substance caused by physical means other than teeth, e.g. toothbrushing.
Abfraction – loss of cervical tooth substance purportedly caused by flexure of teeth under occlusal loading.
However, tooth wear is often a combination of the above mechanisms. E.g. attrition in bruxism sometimes occurs together with erosion. Many clinicians therefore make diagnoses such as "tooth wear with a major element of attrition", or "tooth wear with a major element of erosion" to reflect this.