Bruxism [derived from Greek βρυγμός (brugmós), gnashing of teeth] is grinding of the teeth.
This is an oral para-functional activity observed in most people to some degree. Bruxism affects a great portion of adults and estimates span from 50 to 95%. Bruxism includes clenching and/or grinding of the teeth. Bruxism is caused by the activation of reflex chewing activity; it is not a learned habit. Chewing is a complex neuromuscular activity that is controlled by reflex nerve pathways with higher control by the brain. During sleep, the reflex part is active, while the brain control is inactive. The result is an abnormal chewing action known as bruxism. Some dentists believe it is due to a lack of symmetry in the teeth; others, that it reflects anxiety, digestive problems or a disturbed sleep pattern.
elephants also have bruxism
