Bruxism is excessive teeth grinding and jaw clenching. It is an oral parafunctional activity; i.e., it is unrelated to normal function such as eating or talking. Bruxism is a common problem; reports of prevalence range from 8–31% in the general population. Several symptoms are commonly associated with bruxism, including hypersensitive teeth, aching jaw muscles, headaches, tooth wear, damage to dental restorations (e.g. crowns and fillings) and damage to teeth. However it may cause minimal symptoms, and therefore people may not be aware of the condition.