Bruxism when the parafunctional activity occurs – during sleep ("sleep bruxism"), or while awake ("awake bruxism"). This is the most widely used classification since sleep bruxism generally has different causes to awake bruxism, although the effects on the condition on the teeth may be the same. The treatment is also often dependent upon whether the bruxism happens during sleep or while awake, e.g., an occlusal splint worn during sleep in a person who only bruxes when awake will probably have no benefit. Some have even suggested that sleep bruxism is an entirely different disorder and is not associated with awake bruxism.
Bruxism over 50% of normal infants. Often sleep bruxism develops during adolescence, and the prevalence in 18- to 29-year-olds is about 13%. The overall prevalence in adults is reported to be 8%, and people over the age of 60 are less likely to be affected, with the prevalence dropping to about 3% in this group. A 2013 systematic review of the epidemiologic reports of bruxism concluded a prevalence of about 22.1–31% for awake bruxism, 9.7–15.9% for sleep bruxism, and an overall prevalence of about 8–31.4% of bruxism generally. The review also concluded that overall, bruxism affects males and females equally, and