Temporomandibular Disorders (TMD) are characterized by pain and dysfunction in one or both jaw joints and/or their surrounding tissues. These joints are the most complex in the body. They work as a pair, positioned on either side of the head, connecting the upper ends of the mandible (the lower jaw bone) to the temporal bone of the skull. The joints enable you to move your jaw in three dimensions: up and down, forward and back, and side to side. Serious disruption in the jaw’s function affects the ability to eat, chew, and swallow food; speak and make facial expressions; and breathe and sleep comfortably.
The pain of TMD is often described as a dull, aching pain, which comes and goes in the jaw joint and nearby areas. Some people report no pain, but still have mechanical problems with their jaws. Symptoms can include:
- pain in the jaw muscles
- pain in the neck and shoulders
- chronic headaches
- jaw muscle stiffness
- limited movement or locking of the jaw
- ear pain, pressure
- painful clicking, popping or grating in the jaw joint when opening or closing the mouth
- a bite that feels “off”
Injuries or conditions that affect other joints in the body (like arthritis or fibromyalgia) can also affect the temporomandibular (TM) joints, but for many patients the cause or causes remain unknown. What isknown is that TMD is common and affects 12 percent of the population — some 36 million Americans — at any given time. While both men and women experience TMD, the majority of those seeking treatment are women in their childbearing years. The ratio of female to male patients increases with the severity of symptoms, approaching 9 women for every 1 man with the most severe jaw dysfunction and chronic, unrelenting pain.
Researchers don’t yet have the answer to why women are more likely to seek treatment for TMD, and they are exploring potentially relevant sex differences in jaw anatomy, physiology, pain perception, and responses to pain medications. Female sex hormones are assumed to play a role, since estrogen receptors have been found in jaw tissue and appear to affect pain sensitivity over the menstrual cycle. Investigators are also keenly interested in finding out why some individuals are more susceptible to TMD and why it progresses in some and not in others.
Who is at Risk?
To address these issues, the National Institutes of Health (NIH) has funded the Orofacial Pain Prospective Evaluation and Risk Assessment (OPPERA) study. OPPERA began in 2005, recruited 3,200 18-to-44-year-old volunteers who were initially TMD-free; some developed TMD over the course of the study. Extensive genetic, sensory, demographic, and psychological data were collected on the participants and on a smaller group of TMD patients.
Among the study’s key findings:
- The risk for chronic TMD in women increases between the ages of 18 and 44. In men in the same age range, age was unrelated to TMD incidence.
- Unlike many other chronic pain conditions, chronic TMD incidence does not correlate with low socio-economic status.
- Chronic TMD seems to be associated with alterations in parts of the nervous system that control pain perception.
- TMD patients frequently experience other chronic pain conditions, such as low back pain, headaches, and fibromyalgia.
The study confirms the complexity of TMD and points to factors (including particular genetic associations) that contribute to susceptibility.
The findings on co-morbidity are also consistent with data from independent studies, indicating that these disorders do not exist alone. Rather, they are part of a collection of disorders that are more prevalent in, or are confined to, women — including chronic fatigue syndrome, chronic headache, endometriosis, fibromyalgia, interstitial cystitis, irritable bowel syndrome, and vulvodynia. Like TMD, these are complex conditions, influenced by genetics, sex, and environmental and behavioral factors. When any one of these conditions exists in an individual, it influences and is influenced by the other conditions she or he experiences.
What if You Have TMD?
If you think you have TMD, you may want to see a medical doctor to rule out some of the conditions that may mimic TMD. For example, facial pain can be a symptom of many conditions, such as sinus or ear infections, decayed or abscessed teeth, various types of headache, facial neuralgia (nerve-related facial pain), and even tumors.
If the M.D. or your dentist gives you a diagnosis of a TMD, you need to educate yourself regarding treatment as there is no medical or dental specialty of qualified experts trained in the care and treatment of TMD patients.
Most people with TMD have relatively mild or periodic symptoms which may improve on their own within weeks or months with simple home therapy. Self-care practices, such as eating soft foods, applying ice or moist heat, and avoiding extreme jaw movements (such as wide yawning, loud singing, and gum-chewing) are useful in easing symptoms.
Scientists strongly recommend treating TMD with the most conservative approaches possible. These are treatments that do not cause permanent changes in, or change the structure or position of, the jaws or teeth. Even when the disorders have become persistent, most patients still do not need aggressive types of treatment.
If your problems get worse with time, you should seek professional advice. According to the NIH, complex cases, often marked by chronic and severe pain, jaw dysfunction, comorbid conditions, and diminished quality of life, will likely require a team of doctors from fields such as neurology, rheumatology, pain management and others for diagnosis and treatment. However, first and foremost, educate yourself. Informed patients are better able to communicate with health care providers, ask questions, and make knowledgeable decisions.
Addressing Chronic Pain in Women: A New Research Alliance
The last three scientific meetings of The TMJ Association, Ltd. (TMJA), a non-profit advocacy group, focused on chronic pain conditions that often co-exist with TMD, and explored underlying mechanisms that might link them. Organizations representing four of these conditions — the Chronic Fatigue and Immune Dysfunction Syndrome Association of America, the Endometriosis Association, the National Vulvodynia Association, and The TMJ Association — have joined together to form the Chronic Pain Research Alliance (CPRA).
CPRA is dedicated to alleviating the significant human suffering caused by all the prevalent, neglected, and poorly understood chronic pain conditions that frequently co-occur and disproportionately affect women. These include fibromyalgia, interstitial cystitis, and the pain conditions represented by CPRA’s founders. All told, chronic pain conditions are estimated to affect 50 million American women at an annual cost of $80 billion.
CPRA advocates for, and supports innovative collaborative scientific research. In May 2010, CPRA launched the Campaign to End Chronic Pain in Women, a movement to end discrimination and improve health care for women suffering from chronic pain conditions. The launch was held on Capitol Hill and attended by Congressional members and staff.
CPRA also successfully advocated for women’s pain conditions to be included in the Institute of Medicine’s (IOM) study, Relieving Pain in America: A Blueprint for Transforming Prevention, Care, Education, and Research. Members participated in the report’s release and, most recently, supported a 2012 hearing on the report by the Senate Health, Education, Labor, and Pensions Committee, led by Senator Tom Harkin (D-IA). For more information, see: http://www.endwomenspain.org.
Hope Through Research
The new emphasis on the importance of chronic pain and its high social, emotional and financial cost represents a transformation in attitude of both the research and practitioner communities. In the past, if pain persisted, health care providers regarded it as a failure to cure the patient and avoided the issue—or worse—accused the patient of malingering or being neurotic. Over time, neuroscientists recognized the complexity of pain and, in it its chronic and unrelenting form, now regard it as a disease of the nervous system itself. The IOM report has already had an impact on the National Institutes of Health, recommending that NIH increase support for its Pain Consortium to foster collaborative research across NIH components and, in following up on another IOM recommendation to the Department of Health and Human Services, NIH has convened an Interagency Pain Research Coordinating Committee. Importantly, the committee includes non-government lay members. Women’s health is represented by members from both TMJA and the National Vulvodynia Association.
This article was written by: Joan Wilentz
Joan Wilentz is the Science Writer for The TMJ Association, a national non-profit health advocacy organization with the mission to improve the quality of health care and lives of everyone affected by Temporomandibular Disorders.
The American Association for Dental Research (AADR): relevant information includes the Policy Statement on Temporomandibular Disorders at: http://www.aadronline.org/i4a/pages/index.cfm?pageid=3465
Campaign to End Chronic Pain in Women at: http://www.endwomenspain.org
National Institutes of Health: relevant information includes a brochure on TMJ at: http://www.nidcr.nih.gov/NR/rdonlyres/39C75C9B-1795-4A87-8B46-8F77DDE639CA/0/TMJ_Disorders.pdf
National Institute of Dental and Craniofacial Research: relevant information includes information on treatment options at:http://www.nidcr.nih.gov/OralHealth/Topics/TMJ/TMJDisorders.htm
The TMJ Association: relevant information includes a Resource Guide on TMD, providers lists, questions to ask health care providers, etc at: www.tmj.org