New TMJ study may answer questions about pain

A new study about painful jaw problems could lead to a better understanding of chronic pain and pain disorders.

The results, recently published in the Journal of Pain, provide insights into potential causes of temporomandibular joint and muscle disorders, known as TMJ. Researchers believe their work, the first large scale study of its kind, could lead to new methods of diagnosing facial pain, predicting who is susceptible to them and new treatments.

TMJ is not a single condition, but rather a group of conditions, categorized by acute pain in the jaw joint and chronic pain in the facial area. This cluster of jaw problems is the second most common occurring musculoskeletal condition that can lead to disability, trailing only chronic lower back pain. TMJ radiates through the jaw and muscles, causing pain and tightness in the jaw, neck, and ear. Symptoms include aching facial pain, difficulty chewing, ear aches, pain and tenderness in the jaw, headache, jaw locking, and an uncomfortable or uneven bite.

Researchers with the Orofacial Pain Prospective Evaluation and Risk Assessment study (OPPERA) followed an initial group of 3,200 pain-free people, aged 18 to 44, between three and five years. They found that chronic pain TMJ increased with age in women but not in men. This finding overrode assumptions that pain was greatest in childbearing years for women but decreased with age. The study also found genetic factors that were linked to chronic TMJ. These genes were identified, resulting in the possibility of creating drugs for these and other chronic pain conditions that are related to TMJ.

“This novel study will also allow us to learn more about pain disorders in general, and will improve our ability to diagnose and treat chronic pain conditions across the board,” said Dr. William Maixner, program director for the study and director of the Center for Neurosensory Disorders at the University of North Carolina at Chapel Hill School of Dentistry. “OPPERA is allowing us to study potential biological, psychological and genetic risk factors over a longer period of time, so we will be able to better evaluate the association of these factors.”

While trauma is often the cause of TMJ, there are many times when the cause isn’t clear. The Mayo Clinic states that some of the reasons for jaw pain, tightness, and clicking include the disk eroding out of alignment, a damaged joint, arthritic damage to the cartilage of the joint and fatigued muscles that should be stabilizing the joint. Simply put, even every day occurrences such as grinding your teeth at night or clenching your jaw may lead to the condition.

Perhaps the most outstanding finding in the study was finding a range of biological and psychological factors that contribute to the pain of the condition. People with TMJ are more sensitive to pain, even just mildly painful stimulation, than those that do not have the condition. They have a higher heart rate that increases greater during stress. They are also more aware of their body’s sensations than those without TMJ. These findings may conclude that TMJ is partially connected to the ability to suppress pain and the perception of pain.