What Makes Our Teeth Chatter?
When one is cold there is apt to be a spasm of shivering over which the brain does not seem to have any control. The spasm causes the muscles of the jaw to contract very quickly and as soon as they are contracted, they let the jaw fall again of its own weight. This occurring many times in rapid succession is what causes the teeth to chatter.
There are two kinds of spasms, “clonic” and “tonic.” In the former, the muscles contract and relax alternately in very quick succession, producing an appearance of agitation. In the latter, the muscles contract in a steady and uniform manner, and remain contracted for a comparatively long time.