TMJ: The Research

Why is research about TMJ so important?

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

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.