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New Report on Temporomandibular Disorders: Priorities for Research and Care

Over a year and half ago, the National Academy of Medicine (NAM) began the most comprehensive study ever undertaken on Temporomandibular Disorders (TMD). The study assessed the current state of TMD research, education and training, the safety and efficacy of clinical treatments, and associated burden and costs.

Statement by NIDCR Acting Director on the National Academies of Sciences, Engineering, and Medicine Report on Temporomandibular Joint Disorders

I am pleased to announce the release of the National Academies of Sciences, Engineering, and Medicine (NASEM) report, Temporomandibular Disorders: Priorities for Research and Care. As underscored by the comprehensive report, temporomandibular joint disorders (TMJDs) are a diverse and still poorly understood set of complex, painful conditions affecting the jaw muscles and tissues, temporomandibular joints, and associated nerves. Clearly, there is much more to be understood, and these conditions continue to confound medical and dental health care providers and researchers.

Have you seen the film Dark Waters?

The Film. Dark Waters is about attorney Robert Billott's real-life 20 year legal battle against DuPont chemical for releasing toxic waste - perfluorooctanoic acid, or PFOA - into Parkersburg, West Virginia's water supply, with devastating health effects on the townspeople and livestock. PFOA, also known as C8, is a man-made chemical. It is used in the process of making Teflon and similar chemicals known as fluorotelomers.

Online TMD Diet Diary Research Project

Online TMD Diet Diary Research Project The TMJ Association received the following request from Professor Justin Durham and his research team at Newcastle University. We encourage TMJ patients to participate in this project as it is an under researched

Drug Induced Bruxism

The authors of this article state that orofacial movement disorders (bruxism) are treated typically by dental professionals and not by those specialists (neurologists) researching and treating the other movement disorders (Parkinson's disease, Huntington's disease, tremors, etc.). Again, this is more evidence of the complexity of TMD and the need for multidisciplinary research and treatment in TMD.

Repeated Injections of Botox into the Masseter Muscle... A Longitudinal Study

  • Oct 5, 2017

We thank Dr. Susan Herring for writing the following article summary.

Lee HJ, Kim SJ, Lee KJ, Yu HS, Baik HS. Repeated injections of botulinum toxin into the masseter muscle induce bony changes in human adults: A longitudinal study.   Korean J Orthod. 2017 Jul;47(4):222-228. 

The authors of this study examined mandibular bone before and after subjects received Botox injections into each masseter muscle. These volunteers were healthy adults (22-48 years old), both male and female, who wanted injections to slim their faces. (This happens because the Botox causes temporary muscle paralysis and the masseters undergo atrophy when they are not used.) The 20 subjects were randomized into two groups. One group received a single dose of Botox in each muscle while the second group got two doses. The second dose was given 4 months after the first. The bone scans were cone-beam computed tomography (CBCT), a 3-D technique with relatively low radiation. The after-Botox CBCT scan was performed 6 months after the initial injection. The scans were directed at the mandibular angle, where the masseter attaches. The TMJ region was not examined.

Even 6 months after a single injection, the masseter muscles were much smaller than before injection (loss of about 70 mm2). Predictably, the shrinkage was much greater for the two-injection group (loss of about 140 mm2).

The very limited amount of mandibular bone examined is only part of the masseter's attachment, and an unaffected muscle, the medial pterygoid, attaches to it as well. Therefore, it is surprising that the authors were able to document a loss of bone volume which was statistically significant in the 2-injection group. The loss was due to thinning of the bone, because the mandible as a whole did not become smaller. The authors refer to this finding as an "unwanted side effect" of multiple Botox injections of the masseter muscles.

This study was not ideal and leaves many questions unanswered. Sample size was small, there were no uninjected control subjects, differences between the groups at the start were not reported, the bone examination was very restricted, and it is unknown whether full restoration of muscle and bone would eventually have occurred.  

Nevertheless, it is the first prospective, randomized, longitudinal study of the effects of Botox on the human jaw. The finding of bone loss is consistent with the only other human Botox study on jaws, a cross-sectional examination of the condylar bone of TMJ disorder patients who did or did not receive masseter injections (Raphael et al. 2014). The paper by Lee et al. reinforces the idea that thinned and weakened jaw bones are likely side effects of Botox treatment.

 Raphael, K. G., A. Tadinada, J. M. Bradshaw, M. N. Janal, D. A. Sirois, K. C. Chan and A. G. Lurie (2014). Osteopenic consequences of botulinum toxin injections in the masticatory muscles: a pilot study. J Oral Rehabil 41: 555-563.

Read the full article: https://synapse.koreamed.org/Synapse/Data/PDFData/1123KJOD/kjod-47-222.pdf

TMJ Disorders

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