The cartilage in the jaw joint is thought to slip forward because of
overuse of the muscles surrounding the jaw. This overuse commonly produces tightening of the muscles and may occur as a result of chewing habits, such as grinding or clenching the teeth when under stress, or at night.
Nail biting or holding things between the teeth can also cause jaw joint problems.
Less commonly, missing back teeth, an uneven bite, or an injury to the jaw, can lead to the problem.
Often no obvious cause is found.