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 sleep, the voluntary muscles are inactive due to physiologic motor paralysis, and the jaw is usually open. Some bruxism activity is rhythmic with bite force pulses of tenths of a second (like chewing), and some have longer bite force pulses of 1 to 30 seconds (clenching). Some individuals clench without significant lateral movements. Bruxism can also be regarded as a disorder of repetitive, unconscious contraction of muscles. This typically involves the masseter muscle and the anterior portion of the temporalis (the large outer muscles that clench), and the lateral pterygoids, relatively small bilateral muscles that act together to perform sideways