Bruxism is the act of clenching or grinding your teeth, either out of habit or unconsciously. Though some people grind their teeth unwittingly during the day, most tooth grinders engage in what's called nocturnal bruxism — nighttime tooth grinding or clenching that occurs during sleep. Doctors and dentists sometimes refer to these people as "bruxers."
If you are a nocturnal or sleep bruxer, your upper and lower teeth come clench together forcefully during the night — with a pressure of up to 700 pounds per square inch. (Normal daytime pressure, if you were to clench your teeth right now while reading this article, would be 200 pounds per square inch.)
There are two forms of night bruxism: clenching and grinding.
- If you clench your jaw without moving it around, the jaw remains clamped together forcefully for a sustained length of time.
- If you grind, your lower jaw moves side-to-side while clenched, making a distinctly unpleasant squeaking sound that can send your sleep partner running from the room.
All bruxism is classified as a parafunctional behavior, meaning it's a movement of the body that serves no purpose. Nocturnal bruxism is considered a movement disorder, and it's quite often associated with other sleep disorders like obstructive apnea and restless leg syndrome.
However, if you grind your teeth at least 2 to 4 times per hour, your bruxism may be diagnosed as a sleep disorder in and of itself. (A sleep study would be required to verify this.)