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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.

Botox's Effect on the Jaw Joint

  • Oct 27, 2016

Dr. Susan Herring and her colleagues presented their own research findings at the International Association for Dental Research (IADR) meeting in March of this year.  Dr. Herring prepared the following lay summary for our readers:
Mandibular loading and bone quality following injection of botulinum neurotoxin type A in the masseter muscle
Rafferty K.,  Liu Z-J., Ye W.,  Slamati A. ,Gross T., Herring S., Oral Presentation at the 89th General Session & Exhibition of the IADR, San Diego, CA, March 19, 2011.
Botox works by inactivating the nerve endings that cause muscles to contract, thus paralyzing the muscle.  The paralysis usually lasts for a few months, although the muscles may remain visibly small for longer times.  Some providers feel that treating the jaw muscles of TMD patients with Botox could be helpful even if the muscles are not in spasm.  For example, it has been argued that the jaw muscles place loads on the TMJ, and if these loads are temporarily removed, the joint might have a chance to recover.
One possible worry about unloading joints, however, is that bone strength might be lost from the unloaded area, similar to astronauts losing bone strength while in space.  Because bone is rebuilt slowly, the jaw joint might actually lose needed structure.
To test this idea an animal study was carried out.  In 40 adult female rabbits, one masseter muscle was injected with either saline or Botox, with a dose adjusted to be comparable to a human dose.  The muscles and mandible were examined 4 weeks later, when the masseter would still have been affected by the Botox, and 12 weeks later, when the muscle was expected to have recovered.
The rabbits did not experience problems in chewing and seemed comfortable.  As expected, the Botox-injected masseter muscles were atrophied at 4 weeks.  They were larger at 12 weeks but still statistically smaller than the other side.  From this and other evidence, the experiment was successful in unloading the jaw.  However, this unloading did have adverse effects on bone content, especially for the mandibular condyle (the mandibular part of the TMJ) on the Botox-injected side.  On average, 40% of bone area was lost from the head of the mandibular condyle 4 weeks after injection, and after 12 weeks the bone of the condylar head was still depleted by 22%.  The bone loss occurred in the porous bone in the internal region of the condyle, which has limited capacity to regenerate once it is lost.
In conclusion, 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.

TMJ Disorders


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In Treating TMJ

To view or order a free booklet about TMJ Disorders, visit the National Institutes of Health website.

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