There are usually considered to be three reasons for noncarious tooth surface loss. Abfractions should also be considered to be a cause of non-carious TSL.
Erosion is a chemical process in which the tooth surface is removed in the absence of plaque. Erosive factors may be either intrinsic or extrinsic. Extrinsic sources include drinks such as fresh fruit juices, carbonated drinks, cordials and alcoholic beverages; and some foods and industrial processes. Intrinsic sources include gastro-oesophageal reflux and eating disorders, amongst others.
External agents which have an abrasive effect on the teeth include toothbrush bristles and dietary factors.
Attrition is a process in which tooth tissue is removed as a result of opposing tooth surfaces contacting during function or parafunction. Such direct contact occurs at proximal areas, on supporting cusps and on guiding surfaces during empty grinding movements.
4. Abfractions (stress lesions)
It has been suggested that the stress lesion or abfraction is a consequence of eccentric forces on the natural dentition. The theory propounds tooth fatigue, flexure and deformation via biomechanical loading of the tooth structure, primarily at the cervical regions. Cusp flexure causes stress at the cervical fulcrum and results in loss of the overlying tooth structure. The lesion is typically wedge shaped with sharp line angles, but occlusal abfractions may present as circular invaginations. The magnitude of tooth tissue loss depends on the size, duration, direction, frequency and location of the forces. It should be remembered that abfractive lesions are caused by flexure and fatigue of susceptible teeth at sites that are usually distant from the point of loading. Other factors, such as erosion and abrasion may play a significant role in tooth tissue loss, but the initial force is the biomechanical loading.
Bruxism (from the Greek βρυγμός (brugmós), gnashing of teeth) is the grinding of the teeth, and is typically accompanied by the clenching of the jaw. It is an oral parafunctional activity that occurs in most humans at some time in their lives. In most people, bruxism is mild enough not to be a health problem; however, 25% of people suffer from significant bruxism that will become symptomatic. While bruxism may be a diurnal or nocturnal activity, it is nocturnal bruxism which causes the majority of health issues, and can even occur during short naps. Bruxism is one of the most common sleep disorders.