Prolonged, unintentional grinding and clenching of the teeth, usually occurring during sleep. ‘Bruxers’ are often unaware that they have developed this habit. Symptoms include abraded/chipped teeth (in extreme cases, waking up with tooth chips in the mouth); facial pain; oversensitive teeth; tense facial and jaw muscles; headaches; dislocation of the jaw; damage to the tooth enamel, exposing the inside of the tooth; a popping or clicking in the temporomandibular joint (TMJ); tongue indentations; damage to the inside of the cheek.