© 2000 by Dr. Moti Nissani

The word bruxism is taken from the Greek word brychein: gnashing of teeth. Although the term bruxism is not generally known to lay people, it is shorter and more convenient than teeth clenching or grinding. For this reason, and because that’s the way it can be found in the professional literature, I shall use it in all my internet informational links.

Bruxism, unfortunately, means different things to different experts. So we must try to clarify the terminological confusion that still surrounds this subject. Bruxism can perhaps be best defined as the involuntary, unconscious, and excessive grinding, tapping, or clenching of teeth. When it occurs during sleep, it may be best called sleep bruxism. A few people, on the other hand, brux while they are awake, in which case the condition may be called wakeful bruxism.

The above terms are preferrable to the widely-used nocturnal and diurnal   bruxism, for the simple reason that one may engage in sleep bruxism during the day and in wakeful bruxism during the night. The distinguishing factor between these related conditions is obviously sleep, not sunlight.

All forms of bruxism entail forceful contact between the biting surfaces of the upper and lower teeth. In grinding and tapping this contact involves movements of the lower jaw and unpleasant sounds which can often awaken housemates. Click here to hear the grinding of one patient (who has been grinding her front teeth, some 12 minutes a night,  for the past 50 years).   Clenching (or clamping), on the other hand, involves inaudible, sustained, forceful tooth contact unaccompanied by mandibular movements.

It's important to note that the difference between bruxers and non-bruxers is one of degree, not kind.  Most people probably grind and clench their teeth now and then, but such behavior does not a bruxer make. Moreover, some people may be able to sustain the bruxing forces involved with no apparent ill effects. Thus, we should perhaps talk about bruxism only when the habit is persistent enough, frequent enough, long enough, or intense enough to damage the teeth and to lead to other complications. So, in my hypertxt, an operational definition of bruxism is used: One’s grinding, tapping, or clenching of teeth fall under the rubric of bruxism only when they have already affected, or are expected to affect, one’s well being.