UB Dental Studies On TMD Could Lead to Better Treatments

BUFFALO, N.Y. -- Studies conducted by a University at Buffalo dental researcher could lead to better treatments for temporomandibular disorders (TMD), a condition that can affect sufferers' abilities to eat, swallow, yawn -- and kiss.

Richard Ohrbach, assistant professor of oral diagnostic sciences, and colleagues at UB and the University of Washington recently presented the results of their research at the combined meeting of the American Association of Dental Research and the International Association for Dental Research.

Their research could have an impact on treatment of TMD and other chronic pain disorders.

TMD is characterized by pain or dysfunction of the masticatory system, especially in the muscles that control jaw function. The condition is not necessarily associated with any identifiable pathophysiology, although it may be the result of injury or degenerative joint disease.

The condition can lead to difficulties with eating, drinking, swallowing, talking -- any activity that involves the mouth and jaw, even kissing, Ohrbach said.

Approximately 5 percent of the general population has TMD symptoms severe enough to warrant treatment. As much as 15 percent of the general population may experience symptoms at any time, but not severe enough to require treatment.

Ohrbach's research examined the effect of treatments such as relaxation and muscle rehabilitation and the dimensions of signs and symptoms, as well as how to quantify the impact the condition has on sufferers' quality of life.

In a study that examined the effects of relaxation on TMD symptoms, participants randomly were assigned to spend 30 minutes a day listening to a relaxation tape or, as a control group, to the music of their choice for the same time period.

Also as part of the study, researchers examined the effects of muscle rehabilitation by randomly assigning members of another group jaw-stretching exercises.

Chronic pain often is accompanied by muscle tightness and shortening, Ohrbach explained. Researchers theorize that the shortening partly may cause the pain, but stretching the muscle to

reduce the shortening also causes pain. Researchers wanted to study whether stretching into pain could result in better pain reduction.

Participants were divided into three groups for muscle-rehabilitation treatment. One group stretched its jaw muscles, but stopped short of the point where stretching caused pain. The second group was asked to stretch into pain. The third, control group, was asked to massage its jaw muscles.

After three weeks, all study participants were asked to rate their symptoms according to their level of pain, the amount they were able to open their mouths without pain, how well they were coping with their symptoms and how much pain accompanied opening.

Much to researchers' surprise, both the relaxation and music groups showed similar results.

"In terms of this treatment, everyone improved significantly on a variety of variables," said Ohrbach. "Everyone became more proactive in managing their pain and there was a decrease in the tendency to avoid dealing with pain."

Relaxation, he noted, is a powerful procedure that required participants to reorganize their lives. "It's about finding time in the day for yourself."

Managing time and taking control are fundamental to pain management, Ohrbach added, noting that of the 41 people who started the program, 11 dropped out because they could not find the time to do the 30-minute relaxation exercise.

Researchers also found that participants who had stretched into pain, compared to the other muscle treatments, reported a significant decrease in their TMD pain when opening their jaws, suggesting a way to improve a treatment already often used.

James Uyanik, a senior honors student, helped design and conduct the research study.

A second study, conducted in collaboration with Carl Granger, professor and chair of the Department of Rehabilitation Medicine in the School of Medicine and Biomedical Sciences; Samuel Markello, research assistant professor in the Department of Rehabilitation Medicine, and Brenda Horrell, a graduate student in the Department of Oral Diagnostic Sciences in the School of Dental Medicine, looked at developing a reliable measure of jaw disability. The scale looked at the hierarchy of increasing disability associated with common behaviors, such as eating, drinking, swallowing and talking.

The project was designed to allow researchers to develop a scale that would allow health practitioners to assess the impact of TMD on patients in terms of functional limitations.

"The assessment of disability in chronic pain has been elusive," Ohrbach said.

A third study looked at trying to understand the physical and psychological dimensions that explain the problems that TMD sufferers have.

"We can measure limitations in range of motion and tenderness, noises in the jaw joints -- classic characteristics -- and from that can come up with a physical diagnosis (of TMD)," said Ohrbach. "We have a lot of ways to measure pain."

But researchers have had limited ways to quantify the more complex, interlinked symptoms that characterize the disease, he added, and even more limiting was how to understand the interrelationships.

Colleagues at the University of Washington -- Samuel Dworkin, Linda LeResche and Edmund Truelove -- conducted a five-year study of TMD pain. One goal was to better understand the relationship between TMD pain, the physical characteristics and the psychological impact that can accompany the disease, such as depression, anxiety and somatization, or non-specific physical symptoms.

The results show that there are reliable and largely independent aspects that characterize TMD: pain, physical status and psychological status, suggesting that all three domains need attention because each exerts its own impact on the individual.

Results of these findings will be used to develop more effective treatment programs for TMD sufferers, as well as hopefully earlier intervention.

"We're trying to understand the dimensions that explain the problems people have," Ohrbach said. "One common view is that psychological and behavioral issues are an expression or manifestation of the physical symptoms.

"A lot of people who have pain have problems that extend beyond the body," he continued. "The pain may have begun with something that is wrong with the body, but there are secondary problems that keep the patient seeking treatment for something that often no longer exists, at least in its original form. Our research, and that of others such as my colleagues at the University of Washington, indicate that these multiple aspects cannot be ignored."