• Tender or sore jaw muscles. Your jaw may be even more painful when you wake up, clench your teeth, chew your food or yawn.

• Problems opening or closing your mouth. It may be hard to open or close your jaws all the way, or your jaws may lock open or closed.

• Headaches that you cannot explain. You may also feel pain in your neck. These may be caused by TMD, or by other problems. Tell your dentist AND your doctor.

• A clicking or grinding noise when you chew or yawn. You may hear strange noises in your jaw joints, such as clicking or popping when you open your mouth, or crunching and grinding sounds when you chew.

• Clenching and grinding your teeth. Clenching your jaw muscles can cause them to ache. Some people grind their teeth or clench their jaw muscles when they are under stress.

• Injury to your face or jaws. Broken (or fractured) jaws, a jaw joint that has been knocked out of place (or dislocated) and "whiplash" may cause TMD.

• Some diseases, such as rheumatoid arthritis, may affect the jaw joints and muscles.

• If your jaw does not grow the right way, your teeth may not line up the way they should. This can make it hard to bite and chew, and may lead to TMD.