Overview of bruxism

Bruxism is repetitive teeth clenching, teeth grinding, or bracing or thrusting of the mandible. It can occur during sleep or when awake.

The aetiology of sleep bruxism is complex and multifactorial but is not fully understood. There is no evidence that occlusal factors cause sleep bruxism. In sleep bruxism, rhythmic masticatory muscle activity peaks in the minutes before rapid eye movement (REM) sleep, suggesting that its onset is related to sleep-stage transitions.

Tooth grinding during sleep, which is usually noted by a sleep partner, is common. However, in the sleep laboratory, approximately 50% of people with a history of tooth grinding have low frequencies of jaw muscle contractions and tooth grinding. It remains to be clarified when tooth grinding becomes a disorder associated with negative consequences such as tooth damage and pain.

Bruxism may rarely be a sign of orofacial dyskinesia, or occur following a head injury. Acute oromandibular dystonia or tardive dyskinesia caused by dopamine antagonist antiemetic drugs (eg metoclopramide, prochlorperazine) or antipsychotic drugs may be mistaken for bruxism.

Common triggers of bruxism lists common triggers of bruxism.