Before we ask whether Botox can help reduce your TMJ pain, we need to ask a more basic question: Is it safe to use Botox this way? When injected into muscles, Botox causes a partial paralysis of those muscles. The paralysis changes the forces causing normal stress on the TM joint. These forces are considered necessary to maintain the usual process of breakdown and regrowth of bone. If the paralysis changes bone remodeling in the TMJ area, injection of Botox into the chewing muscles might cause unique safety concerns and unknown long-term problems.
In an important first step to addressing these concerns, Dr. Susan Herring and her colleagues at the University of Washington in Seattle examined the effect of Botox injections into the jaw muscles of rabbits. In the August 2011 issue of TMJ News Bites, Dr. Herring summarized her findings. She concluded "Botox in the masseter caused an osteoporotic condition in the TMJ of rabbits, raising some concern that this treatment might not be healthy for the joint in the long term."
These findings indeed raised concerns, but it was unclear whether findings from a rabbit study had relevance for humans. With the cooperation of the TMJ Association, Dr. Karen Raphael and colleagues at New York University posted an online survey on the Association's website, to identify women who had received TMJ injections in their chewing muscle and a similar group of TMJ patients who did not. Among the 150+ women who completed the survey, Dr. Raphael and colleagues invited a small group of well-matched Botox recipients and nonrecipients, all with TMJ pain, to participate in a study intended to determine whether Dr. Herring's animal findings had relevance for humans. Ultimately, as published in the May 2014 issue of the Journal of Oral Rehabilitation, 7 women who had been treated with Botox for their TMJ pain and 9 matched women who had never received Botox underwent specialized radiological imaging of their TMJs. The images were evaluated by oral and maxillofacial radiologists who did not know their treatment history. The radiologists found abnormally low bone density in the TMJ area in all of the women treated with Botox and in none of the women who did not receive Botox .
These findings indicated that more research on the safety of Botox for TMJ pain treatment is essential, to guide both patients and health care providers. We are happy to report that the National Institutes of Dental and Craniofacial Research (NIDCR) of the NIH has provided a grant to Dr. Raphael's team to conduct a much larger study addressing the safety of Botox treatment. If it is found to be a safe treatment when injected in the chewing muscles then, and only then, we can we address broader questions of whether it actually helps reduce the pain of TMJ disorders.