Bruxism into three groups, namely central or pathophysiological factors, psychosocial factors and peripheral factors. The World Health Organization's International Classification of Diseases 10th revision does not have an entry called bruxism, instead listing "tooth grinding" under somatoform disorders. To describe bruxism as a purely somatoform disorder does not reflect the mainstream, modern view of this condition (see causes). The ICSD-R described three different severities of sleep bruxism, defining mild as occurring less than nightly, with no damage to teeth or psychosocial impairment; moderate as occurring nightly, with mild impairment of psychosocial functioning; and severe as occurring nightly, and with damage to
Bruxism damage may be similar in both types, but the symptoms of sleep bruxism tend to be worse on waking and improve during the course of the day, and the symptoms of awake bruxism may not be present at all on waking, and then worsen over the day. The causes of bruxism are not completely understood, but probably involve multiple factors. Awake bruxism is more common in females, whereas males and females are affected in equal proportions by sleep bruxism. Awake bruxism is thought to have different causes from sleep bruxism. Several treatments are in use, although there is little evidence