Q. My wife tells me I grind my teeth at night. Could this explain why I often wake up with a headache?
A. Tooth grinding and clenching are symptomatic of a condition known as bruxism. It can lead to temporomandibular joint (TMJ) disorder that, in turn, can cause headaches.
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People who grind their teeth during sleep usually rub their lower teeth against their upper teeth in a back-and-forth or side-to-side motion. It sounds like chewing on hard crackers or ice cubes. Clenching is more like a rocking motion of the lower teeth against the uppers. Some people don't realize they have bruxism unless a bed partner mentions it or a dentist points out worn-down areas on the teeth.
Some people with bruxism also clench their jaw repeatedly during the day. It may be when they are angry or agitated, but often they just do it, for no good reason. They're not even aware they do it. But it can add to the damage done to the teeth.
The temporomandibular joints are flexible joints found on each side of your head just in front of the ear. They connect your lower jaw to the temporal bone of the skull. (I've put an illustration of the joints and muscles associated with TMJ disorder on my website, AskDoctorK.com.) TMJ disorder can cause dull, deep morning headaches that may or may not subside during the day.
People who frequently grind their teeth can develop stiff neck muscles -- a possible trigger for headaches. The pain of these headaches usually centers around the sides and back of the head. Other symptoms of TMJ disorder include a clicking or popping of the jaw joints, pain in or around the jaws, and locking or limited opening of the mouth.
If you think your headaches might be due to bruxism or TMJ disorder, consult your dentist. He or she may refer you to a pain specialist.
A dental night guard can help reduce the symptoms of bruxism. This is a small piece of hard plastic custom-fitted to your upper teeth. People who clench their jaw repeatedly during the day are advised to wear the "night" guard even during those times of the day when they are working alone and don't have to talk to others.
Many people with bruxism and TMJ benefit from stress management to relax stiff head and neck muscles. This may include regular exercise and learning relaxation techniques. In rare cases, you may need surgery to correct a damaged joint. Treatment at bedtime with muscle relaxants is recommended by some experts, although that proposed treatment has not been subjected to large-scale studies.
Why do people grind their teeth at night? I wish we knew. It's one of the many common conditions that doctors understand poorly. While stress may provoke it in some people, there are plenty of other people who live with lots of stress and never grind their teeth.
• Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com.