The cause of bruxism, known as clenching or grinding, is unknown. It is thought to be due to stress.

The vast majority of bruxist patients clench or grind their teeth during sleep at night. However, there are many patients who notice that they are clenching their teeth during the day. While bruxism can cause wear on the tooth surfaces, breakage or cracks in the teeth, it triggers the formation of a square-looking face in the patient with excessive growth in the chewing muscles of the patient. Patients who grind their teeth at night may wake up with jaw, joint, ear and even back and neck pain in the morning.

In the treatment of bruxism, night-time appliances and/or Botox are applied to the chewing muscles.