What Causes TMD?
We don’t know what causes TMD. Dentists believe symptoms arise from problems with the muscles of your jaw or with the parts of the joint itself.
Injury to your jaw, the joint, or the muscles of your head and neck -- like from a heavy blow or whiplash -- can lead to TMD. Other causes include:
Grinding or clenching your teeth, which puts a lot of pressure on the joint
Movement of the soft cushion or disc between the ball and socket of the joint
Arthritis in the joint
Stress, which can cause you to tighten facial and jaw muscles or clench the teeth