Why Do Your Teeth ChatteR?
The most common reason your teeth chatter is because you are cold. When your body gets the sense that its internal temperature might drop below 98.6 degrees Fahrenheit (37 degrees Celsius), it starts to shiver, during which the muscles rapidly relax and contract, as National Institutes of Health explains it. When shivering occurs in the jaw muscles, it moves the jaw up and down, causing clicking teeth.
In some cases, your teeth might chatter and you might shiver not because you're cold, but because your body is trying to fight off an infection. In that case, you might notice a fever and an increase in body temperature, along with the chattering and shivering.
There are also cases when chattering teeth have nothing to do with the cold. For example, people who have bruxism might seem to chatter their teeth in their sleep.
Teeth chattering can also be associated with oromandibular dystonia, a condition that causes "forceful contractions" in the jaw or face muscles, according to the Dystonia Medical Research Foundation. Constant muscle movements in the jaw cause the teeth to clatter together. Oromandibular dystonia can occur on its own or it can be symptom of another condition, such as Parkinson's disease or Wilson's disease. In some instances, the condition develops as a reaction to certain medications.