Also Known As: Teeth Grinding, Bruxism, Grinding Teeth
Bruxism (from the Greek βρυγμός (brygmós), "gnashing of teeth") is characterized by the grinding of the teeth and typically includes the clenching of the jaw. It is an oralparafunctional activity that occurs in most humans at some time in their lives. In most people, bruxism is mild enough not to be a health problem. While bruxism may be adiurnal or nocturnal activity, it is bruxism during sleep that causes the majority of health issues; it can even occur during short naps. Bruxism is one of the most common sleep disorders.
It is also a common side effect of stimulant medications.
Bruxism is a habit rather than a reflex chewing activity. Reflex activities happen reliably in response to a stimulus, without involvement of subconscious brain activity. Chewing and clenching are complex neuromuscular activities that can be controlled either by subconscious processes or by conscious processes within the brain. During sleep, (and for some during waking hours while conscious attention is distracted) subconscious processes can run unchecked, allowing bruxism to occur.
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). Researchers classify bruxism as "a habitual behavior, and a sleep disorder."
The etiology of problematic bruxism can be quite varied, from allergic reactions or medical ailments, to trauma (such as a car crash) to a period of unusual stress, but once bruxism becomes a habit, the original stimulus can be removed without ending the habit. Certain medical conditions can trigger bruxism, including digestive ailments and anxiety. In a Finnish twin study, the heritability of liability to sleep-related bruxism was estimated at 52%, with the rest of the variance attributed to non-shared environmental effects.