Tooth clenching is a habit that occurs when the jaw muscles undergo heavy, repeated, prolonged contraction, bringing the biting surfaces of the teeth together in the absence of food. Tooth grinding is a similarly destructive habit wherein the jaw muscles force the teeth back and forth over each other. These habits are referred to as bruxism. (See Exhibits 1, 2 and 3).

Causes of bruxism may include the following:

1. Tension or stress
2. High fillings or crowns
3. An uneven bite
4. Chronic or acute low-grade or intense dental pain

Effects of bruxism include the following:

1. Heavy wear patterns (facets) on the edges of the teeth
2. Flattening of the biting surfaces of the teeth
3. Loosening of the teeth
4. Headaches
5. Muscle or joint pain
6. Cracked teeth
7. Accelerated bone loss around the teeth.

It also may be associated with a bad bite. Bruxism may lead to loose, sore or separating teeth, headaches, muscle or joint pain, and cracked teeth. The teeth may become extremely shortened and unattractive, and the jaw muscles may enlarge noticeably. Grinding of teeth may accelerate bone loss around the teeth. It is usually managed by a combination of education and the use of custom made night guards.