Bruxism is characterised by clenching or grinding of the teeth due to contraction of the masseter, temporalis and other jaw muscles. Bruxism may lead to masticatory muscle hypertrophy, tooth surface loss, fracture of restorations or teeth, hypersensitive or painful teeth and loss of periodontal support. Sleep bruxism has previously been viewed as a dysfunctional movement or pathological condition, whereas it is now accepted as a centrally controlled condition with various systemic risk factors. It has been postulated that sleep bruxism may have a protective role during sleep, for example in relation to airway maintenance or in stimulating saliva flow. A diagnosis of sleep bruxism may be made via patient report and clinical interview, clinical examination, intraoral appliances or recording of muscle activity. Bruxism in itself does not require treatment: management is only indicated where problems arise as a result of bruxism. Oral appliances primarily aim to protect the dentition from damage caused by clenching/grinding, although they may reduce muscle activity. Irreversible occlusal adjustments have no basis in evidence in the management of bruxism. Behavioural strategies include biofeedback, relaxation and improvement of sleep hygiene. Administration of botulinum toxin (Botox) to the masticatory muscles appears to reduce the frequency of bruxism, but concerns have been raised regarding possible adverse effects. Dentists should be aware of the potential aetiology, pathophysiology and management strategies of sleep bruxism.