An open and shut case

Stress takes its toll on the human body in many ways. It can cause heart palpitations, head and stomach aches, sweating and irritability. Some people overeat while others lose their appetite.

For about 10 million Americans — many of them women of childbearing age — stress causes severe jaw pain, a condition called TMJ Syndrome.

The term refers to a host of problems affecting the jaw muscles and temporomandibular joint, the hinges located adjacent to the ear that connect the lower jaw to the temporal bone at the side of the head and allow freedom of movement to chew, speak and swallow.

TMJ symptoms include jaw-muscle tenderness, difficulty opening the mouth, jaws that lock and a clicking or popping noise heard when opening and closing the mouth.

Although TMJ isn't new, it continues to be poorly understood, says Jennifer Haythornthwaite, a professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine.

"TMJ is kind of a challenging problem," she says. "It affects work, family and moods, and there aren't any really good treatments."

In women 25 to 55, TMJ often is associated with depression, anxiety, sleep disturbances, gastrointestinal symptoms or frequent infection.

"My jaw feels very tight," says Judy Roos, 52, who has had jaw pain for more than 10 years. Over time, it has become so difficult for her to open her mouth wide that she put off going to a dentist. "It's almost like my face is in a vise and being squeezed."

Studies under way

The TM joints are among the most complex joints in the body. When a person opens his or her mouth, the rounded ends of the lower jaw, called condyles, glide along the joint socket of the temporal bone at the side of the head. When the mouth is closed, the condyles slide back to their original position. To keep this motion smooth, a soft disc that lies between the condyles and temporal bone absorbs shocks from chewing and other movements. Any problem that prevents the complex system from working properly can result in TMJ.

The National Institutes of Health is funding at least six clinical trials of potential treatments for TMJ, from an injected arthritis medication to acupuncture and even spiritual healing.

In Baltimore, two NIH-funded studies are evaluating pain management for TMJ and the interaction between TMJ pain and sleep disorders.

In the first study, funded by a $2.4 million grant from the National Institute of Dental and Craniofacial Research, Haythornthwaite is working with dental experts at the University of Maryland Dental School to evaluate whether a combination of pharmacological and psychological treatments for TMJ is better than either one alone in reducing pain and disability associated with the condition.

Study participants from 18 to 65 who have had TMJ pain for at least three months randomly are assigned to take either the antidepressant nortriptyline — which has been shown to relieve TMJ pain — or a placebo once a day for eight months. Participants also randomly are assigned to receive either education about the condition or a series of cognitive-behavior therapy sessions with a psychologist for stress management.

The therapy sessions use relaxation techniques to help participants break bad habits, says study co-investigator Michael Smith, an assistant professor of psychiatry at Hopkins.

"We teach them to be more aware of what they're doing, like clenching their teeth or biting pencils," Smith says.

About 80 percent of the participants have had treatment for TMJ before, says co-investigator Dr. Edward Grace, director of the Brotman Facial Pain Center at the University of Maryland Dental School.

Treating TMJ

Thirty years ago, TMJ sometimes was treated by surgery to adjust the bite, but now conservative approaches are the standard, Grace says. These include application of moist heat, jaw exercises, over-the-counter pain relievers and relaxation techniques.

There are three common TMJ diagnoses, Grace says: a muscular problem such as discomfort or pain in the muscles controlling the jaw; a functional problem such as a dislocated jaw or disc; or a degenerative joint disease such as arthritis in the jaw.

The good news, he says, is that all three respond well to treatment.

TMJ is a cyclical condition, Grace adds, and can flare up as a result of anything from a psychosocial event such as the death of a family member to a major change in diet.

In a second Baltimore study, funded by an $800,000 grant from the National Institute of Neurological Disorders and Stroke, Smith is following 80 TMJ patients who have sleep disorders such as insomnia, sleep apnea and nighttime teeth grinding or clenching.

The connection between sleep and TMJ pain has not been studied before, Smith says, even though at least 50 percent of TMJ patients report some kind of sleep problems. Either disorder, it seems, can cause the other.

"A bad night's sleep predicts pain, but pain can cause poor sleep," Smith says.