Do you have tenderness or pain in your jaw muscles? Have your teeth been worn down, fractured or chipped? If so, you may have bruxism. Bruxism is a condition in which you grind or clench your teeth and most of the time, you do it unknowingly. This can occur both during the day and while you sleep. Sleep bruxism is generally more severe and may also keep your bed partner awake because of the sound it makes.