TMJ: The Research

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Why is research about TMJ so important? 

Temporo-Mandibular Joint Dysfunction, commonly called TMJ, affects over 10 million people in the United States.

Louis Abbey, DMD:

Louis Abbey taught Oral and Maxillofacial Pathology at Virginia Commonwealth University School of dentistry in Richmond, VA for 33 years. He has retired to the Boston area and is teaching at Harvard School of Dental Medicine and consulting with a pathology laboratory.

Almost all dental (and some non-dental) practitioners have the opportunity to deal with TMJ: general dentists, orthodontists, oral surgeons, ENT specialists, pharmacists, neurologists, dental hygienists and psychiatrists and psychologists. The field is loosely defined and patients get referred around. This results in a lot of frustrated practitioners. The confusion and rejection patients may feel likely just adds to their problem.

However, there are experts in TMJ who like the challenge. I would be very interested in knowing more about the research that is being done. TMJ is a difficult area to investigate because of the lack of a clearly defined disease process, the lack of a focus of practitioners who treat the problem and the confusing body of existing knowledge of etiology, pathogenesis and treatment.

Terrie Cowley:

Terrie Cowley is the founder and President of the Board of Directors of the TMJ Association, Ltd. The association motto is "Changing the Face of TMJ" and their website is www.tmj.org/.

TMJ is a very complex condition affecting primarily women in their childbearing years. When we finally get a handle on what we are currently calling TMJ, I think it will eventually shake down to a number of different conditions - a number of subsets of patients. TMJ patients have 3 times the normal use of health care resources, and it is not for management of TMJ but for a number of other conditions, like reproductive issues, immunological problems, etc. There are connections between TMJ and a number of other health issues raising questions whether TMJ is an isolated condition or one aspect of a constellation of conditions.

John Kusiak, Ph.D:

John Kusiak, Ph.D. is the Director, Molecular and Cellular Neurobiology Program, Division of Basic and Translational Sciences, at the National Institute of Dental and Craniofacial Research

The National Institute of Dental and Craniofacial Research (NIDCR) has the lead role at the National Institutes of Health in sponsoring research on temporomandibular joint and muscle disorders, or TMJDs. These are a set of pathological conditions involving the TMJ, muscles of mastication and contiguous tissues. They pose a number of challenges for patients and their health care providers.

There's no shortage of research questions when it comes to TMJD. The NIDCR is sponsoring research aimed at discovering the biological mechanisms underlying the disorders. The investigators are combining approaches from several disciplines-including cell biology, neurobiology, molecular biology, neuroendocrinology and genetics-to uncover the etiological and pathological processes. The Institute is planning research initiatives to more effectively transfer basic scientific knowledge into treatments for TMJD and to stimulate research on associations between TMJD and other musculoskeletal disorders.

On another front, NIDCR is supporting innovative, interdisciplinary research to elucidate the molecular mechanisms underlying the orofacial pain that is a primary symptom of TMJD. This research uses cutting edge genomic and proteomic approaches, as well as imaging technologies, to reveal the molecular events and pathways involved in chronic orofacial pain. It also seeks to understand the mechanisms by which acute pain becomes chronic and how hyperexcitability of neuronal pathways can lead to hyperalgesia and allodynia. In addition, scientists are exploring both neuropathic and neuroinflammatory pain mechanisms. The knowledge gained from these research areas, including identification of biomarkers, holds promise for new treatments and preventative measures for orofacial pain.

Recently, NIDCR launched an initiative aimed at an understudied area of orofacial pain research. The initiative will stimulate basic research on the role of glial cells in pain disorders, and in particular the interactions between glial cells and neuronal cells that lead to chronic orofacial pain conditions. Studies will focus on activated microglia, astrocytes and oligodendrocytes and their normal and pathological interactions with neurons and neuronal networks involved in transmission of pain signals in both the peripheral and central nervous systems.

The NIDCR is planning initiatives to fill important gaps in research on TMJD. One addresses the need for more emphasis on translational research, i.e., the integration of results from human studies of TMJD and knowledge of the clinical symptoms and causes of chronic orofacial pain to develop and validate animal models of chronic human pain disorders such as TMJD. The second proposed initiative will examine the etiological and pathological mechanisms underlying comorbid conditions sometimes found in patients with TMJD. The most common symptoms of TMJD overlap with symptoms of other chronic painful conditions such as fibromyalgia, chronic fatigue syndrome, trigeminal neuralgia, and atypical face pain. This initiative will seek to stimulate research on the molecular, physiological and behavioral mechanisms responsible for the overlapping symptoms of TMJD and other disorders. These integrated approaches will help investigators to more rapidly identify new therapeutic targets and approaches for successfully managing chronic pain conditions.

The NIDCR sponsors a Temporomandibular Joint Implant Registry and Repository. This is a research resource for scientists with an interest in studying TMJD-related information and materials. A database, biological samples and retrieved implants are available to basic and clinical researchers. Materials available include DNA isolated from blood, serum, saliva, paraffin TMJ tissue blocks, frozen TMJ tissue blocks and retrieved implants. The materials can help in the understanding of TMJD pathology and could provide information useful for development of new biologically based materials for TMJ implants.