There are two main kinds of bruxism: sleep bruxism and awake bruxism. Sleep bruxism happens when the person sleeps, and awake bruxism happens when the person is awake. Symptoms of sleep bruxism are often worse when waking up. Awake bruxism can feel fine when waking up, then get worse as the day goes on. There may be many reasons why people grind their teeth and clench their jaws. Awake bruxism may have different causes from sleep bruxism. Females are more likely to have awake bruxism. Sleep bruxism affects males as often as females. Several treatments are used, but none are proved to be very effective.