UB Receives $3.3 Million to Study Causes of Facial, Jaw Pain

By Lois Baker

Release Date: January 24, 2006

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UB researchers have received funding for the first large-scale study of risk factors for temporomandibular joint and muscle disorders.

BUFFALO, N.Y. -- The School of Dental Medicine at the University at Buffalo has received $3.3 million to participate in the first large-scale prospective clinical study of risk factors that contribute to the development of temporomandibular joint and muscle disorders (TMJMD).

The multicenter project, called Orofacial Pain: Prospective Evaluation and Risk Assessment (OPPERA), is funded by a $19.1 million grant from the National Institute of Dental and Craniofacial Research (NIDCR).

Four institutions will participate in the seven-year study: UB, the University of Florida in Gainesville, the University of Maryland in Baltimore and the University of North Carolina at Chapel Hill, which will serve as the lead institution. Battelle Inc. in Durham, N.C., will be the data coordinating center.

Richard Ohrbach, D.D.S., Ph.D., associate professor in the Department of Oral Diagnostic Sciences, will head the UB study.

"The significance of this study is that it simultaneously addresses both the genotype and the phenotype of participants and how the interactions between these two unfold over time to influence the experience of pain," said Ohrbach. Genotype refers to an individual's inborn biological potential or destiny, while phenotype is the observable or measurable clinical and constitutional characteristics of the individual.

"Recent developments in genetics pertaining to polymorphisms (variants in gene expression) and in the ability to measure how much pain sensation is being transmitted to the brain's pain centers are the scientific bases underlying this next step in pain research," Ohrbach said.

TMJMD is an umbrella term for a group of conditions that affect the area in and around the two large ball-and-socket joints that connect the jaw to the skull on both sides of the head, the muscles involved in chewing, or both. Common symptoms include persistent pain in the jaw muscles, restricted jaw movement, jaw locking, and abnormal popping and clicking of the joint.

How many people have TMJMD is not known, but the NIDCR estimates that the main symptoms -- pain and restricted jaw movement -- occur in 5-15 percent of Americans. TMJMD may be more common in women than men, and while some conditions can be linked to physical trauma, in most cases the cause is unknown.

The UB study initially will involve 800 "healthy" volunteers who have no TMJMD symptoms. Fifty persons who already have symptoms will be recruited in the second phase. Including those already diagnosed with the disorder is a significant strength of the study, Ohrbach said, because it allows direct analysis of the relation of genetic risk factors to chronic pain.

All participants will undergo a clinical examination, have measurements taken of pain sensitivity and autonomic nervous system function and have blood drawn for pain-related gene analysis. Information also will be collected on current pain, disability, jaw function, mood and stressful events, which may be linked to the onset of TMJMD. All evaluations will take place in the UB Dental School's Center for Orofacial Pain Research, where a neurosensory laboratory has been established for this project.

Healthy volunteers will be tracked from 3-5 years to determine who and how many develop the disorder. The symptomatic group will be monitored for approximately six months to assess factors that affect the disorder. Participants who develop symptoms during the study will provide critical new information on potential risk factors and on the early stages of the disorder, Ohrbach said.

The UB study team also includes Yoly Gonzalez, D.D.S., clinical outcome reference examiner for the four sites; Sharon Baumgartner, UB project manager and clinical examiner, and Theresa Speers, research nurse.

The University at Buffalo is a premier research-intensive public university, the largest and most comprehensive campus in the State University of New York.