Sleep bruxism is classified as a sleep-related movement disorder in the International Classification of Sleep Disorders. It is characterized by frequent occurrence of rhythmic masticatory muscle activity （RMMA） during sleep and often causes clenching and RMMA in combination. There are innumerable and wide-ranging harmful effects due to excessive occlusal force, e.g., attrition, root fracture, destruction of prostheses, severe periodontal disease, and temporomandibular disorders. Therefore, when performing dental treatment, it is important to accurately diagnose sleep bruxism and to provide rational care in accordance with a proper diagnosis. In dental practice, conducting a chairside interview and visual/palpation test of the stomatognathic system are important. Sleep bruxism can be classified as primary, in which there is no apparent cause, and secondary, in which a medical etiology is present; a careful review of the patient’s medical history is necessary to differentiate between primary and secondary sleep bruxism. However, the obtained findings comprise only an indirect diagnosis because jaw movement of the patient has not been assessed accurately. The gold standard for diagnosing sleep bruxism is polysomnography （PSG）. By not only measuring the amount of activity of the masticatory muscles during sleep, but also by performing electroencephalography, electrocardiography, measurement of respiration, oxygen saturation, body position, etc., it is possible to understand the physiological status of each patient. In order to perform these measurements, it is necessary for the patient to stay overnight at a sleep lab, which not only imposes a heavy burden on the patient, but also necessitates measurement under an altered living rhythm/sleeping environment. Therefore, it is possible that sleep bruxism may not be accurately detected in the patient. In recent years, a small simple sleep test apparatus utilizing a device capable of accurately measuring sleep bruxism has been developed by putting a pressure-sensitive film in an intraoral splint, allowing the home monitoring of patients. This article reports on the clinical diagnostic methods, management methods and assessment of sleep bruxism and reviews future methodologies.