Parafunctional activity Parafunctional activity A para-functional habit or parafunctional habit is the habitual exercise of a body part in a way that is other than the most common use of that body part. The term is most commonly used by dentists, orthodontists, or maxillofacial specialists to refer to para-functional uses of the mouth, tongue and jaw. Oral para-functional habits may include bruxism (tooth-clenching and/or grinding), tongue tension ("tongue thrusting"), fingernail biting, pencil or pen chewing, mouth breathing, and any other habitual use of the mouth unrelated to eating, drinking, or speaking. Crenated tongue is a descriptive term for when scalloping develops on
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