Bruxism (MDMA, ecstasy) has been reported to be associated with bruxism, which occurs immediately after taking the drug and for several days afterwards. Tooth wear in people who take ecstasy is also frequently much more severe than in people with bruxism not associated with ecstasy. Occlusion is defined most simply as "contacts between teeth", and is the meeting of teeth during biting and chewing. The term does not imply any disease. Malocclusion is a medical term referring to less than ideal positioning of the upper teeth relative to the lower teeth, which can occur both when the upper jaw is ideally
Bruxism in research declined from over 60% of publications in the period 1966–86 to about 10% in the period 1997–2007. In the 1960s, a periodontist named Sigurd Peder Ramfjord championed the theory that occlusal factors were responsible for bruxism. Generations of dentists were educated by this ideology in the prominent textbook on occlusion of the time, however therapy centered around removal of occlusal interference remained unsatisfactory. The belief among dentists that occlusion and bruxism are strongly related is still widespread, however the majority of researchers now disfavor malocclusion as the main etiologic factor in favor of a more multifactorial, biopsychosocial model