Thursday, September 19, 2013

Botox as a treatment for TMJ



As we have learned, muscles contract by the neurotransmitter, acetylcholine (ACh). ACh binds to ACh receptors on skeletal muscle fibers where it can cause the opening of ligand-gated sodium channels in the cell membrane sodium ions then enter the muscle cell causing depolarization, and through a sequence of steps, you have muscle contraction.  Along with muscle contraction, we also discussed ways to inhibit muscle contraction, one of them being through OnabotulinumtoxinA, more commonly known as Botox. 

Botox is a drug prepared from a bacterial toxin, Botulinum toxin A. Botox is more commonly used for cosmetic purposes to remove fine lines and wrinkles, but can also be used medically to treat multiple conditions including, but not limited to: urinary bladder dysfunction, blepherospasms, and chronic migraines (Allergan 2013). 

We also learned about the SNARE protein, SNAP-25, which is required for vesicle fusion and ultimately for the release of ACh from the axon terminal. Botox inhibits muscular contraction by cleaving these SNARE proteins preventing vesicles from fusing with the membrane, ultimately preventing ACh from being released from the axon terminal thereby preventing muscular contraction (Boron & Boulpaep 2012).

Based on my previous clinical experience, the mechanism of muscular contraction, and the causes of TMJ, I thought to myself that Botox could be beneficial temporary (since Botox is not permanent) treatment for TMJ associated pain. Perhaps removing loads of stress on the jaw joint through Botox injections into the masseters, the jaw joint could have time to relax and recover.

People who suffer from persistent TMJ exhibit symptoms of significant jaw pain or tenderness, clicking or popping when opening their jaw, and decreased ability to open their mouth (AAOMS 2013). Researchers speculated that injecting Botox into the masseters might be an effective treatment for people with persistent myofacial pain (Herring 2011). While researchers did see benefits from Botox injections for TMJ pain, Botox as a treatment is not highly recommended due to the cost (Botox is roughly $10-12 per unit, someone with TMJ would likely need at minimum 60 units. That equates to well over $600! And no, insurance will not pay for this)

Another study showed that after 4 weeks post treatment with Botox, the masseters showed significant atrophy […] and showed to be successful in unloading stress on the jaw (Rafferty et. Al 2011). Another more recent study tested the effectiveness of Botox as analgesic treatment for TMJ. Their study revealed a significant decrease of pain and an increased in mouth opening after 3 months (Denglehem 2013). 
Although Botox has been proven to be beneficial in treating the symptoms of TMJ including TMJ associated pain, there are some downfalls such as cost, frequency one would need to get treatment, and how long Botox lasts.  I have both worked around Botox and received Botox over the past few years and can tell you that it wears off in 3-4 months (everyone is different) and if you exercise frequently, treatment will wear off quicker ultimately leading to more of a financial burden. 

Coming from someone who tends to clench at night due to stress, the benefits being a masters student, I would absolutely consider receiving Botox to relieve my jaw from discomfort associated with clenching which will eventually manifest into arthritis of the jaw joint.  

References: 

Herring, S. 2007 Jul. TMJ News Bites: Botox & Myofascial TMJ pain study. 3(4). Retrieved from: http://www.tmj.org/site/newsbites/News_Bites_July_2011.htm

American Association of Oral and Maxillofacial Surgeons (AAOMS). 2008. Temporomandibular Joint (TMJ). Retrieved from: http://www.aaoms.org/conditions-and-treatments/the-temporomandibular-joint-tmj/

Denglehem C, Maes JM, Raoul G, Ferri J. Botulinum toxin A: analgesic treatment for temporomandibular joint disorders. 2012 Feb. 113(1): 27-31. Retrieved from: http://www.ncbi.nlm.nih.gov/pubmed/22240328

Allergan. 2013. Botox (onobotulinumtoxinA). Retrieved from: http://www.allergan.com/products/medical_dermatology/botox.htm

4 comments:

  1. Excellent article from a fellow TMJ pain sufferer! This is something that I would consider as well. But what are the other side effects? Have any of the studies explain how some of the pain associated with TMJ is not explicitly associated with just the Masseters? There are many different types of TMJ that have different underlying mechanisms. For example poor posture, neurological dysfunction, and yes of course stress and teeth clenching are all sources of TMJ. Yes botox is temporary which could be beneficial from someone who would receive the botox once and then proceed to physical therapy to understand and moderate their underlying mechanisms, while freeing them from pain!

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  2. Prior to our physiology lecture, I was not very familiar with the extent of the use of Botox for treatment of different medical conditions, including temporomandibular disorder (TMD). After reading this blog post and its first comment, I decided to research other studies that have been done, and I came across an interesting article in which researchers studied how botulinum toxin (BTX) injections into masticatory muscles of adult rabbits affected muscle, bone and craniofacial functions. Rabbits were injected with BTX in one masseter chosen at random and reevaluated weekly for 4 or 12 weeks. I thought the researchers' most interesting finding was that the bone quality and magnitude, specifically of the mandibular condyle, on the side of the BTX-injected masseter was significantly reduced. Based on this discovery, the researchers believed there was a strong connection between BTX injections and muscle atrophy in the target masseter, resulting in a loss of bite force and ultimately a reduction in bone volume. Because the condyle head contributes to the “ball and socket” hinge of the temporomandibular joint (TMJ), this may lead to potential long-term problems, especially if treatment requires multiple injections, multiple times. While these findings can offer insight into potential risks of using BTX to relieve TMJ pain, further research is needed and continues to be conducted in this area.

    Rafferty KL, Liu ZJ, Ye W, Navarrete TT, Salamati A, et al. 2012. Botulinum toxin in masticatory muscles: short- and long-term effects on muscle, bone, and craniofacial function in adult rabbits. NCBI [Internet]. 50(3): 651-662. Available from: http://www.ncbi.nlm.nih.gov/ pmc/articles/PMC3278508/.

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  3. Kelsey - I am sure there are there are other muscles involved! Most of the studies I looked at only discussed the masseters, but I wonder if the temporalis has any involvement--especially in terms of radiating TMD pain. I did read in one study that there is a side effect of "bone loss." This was discovered in a mouse model, so while the bone loss was not significant, I wonder what degree of bone loss or bone density loss there is in humans.

    Danielle - I think you may have looked at a similar study, I just failed to mention the bone density loss in the mouse model...I strongly believe that Botox is a "bandaid" much like a cortisol injection is for pain anywhere else in the body. It might mask the pain, but true TMD, where it impacts the quality of the mandibular structures is not being addressed.

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  4. You need to follow their recommendations and wear these appliances correctly and keep them clean. I also recommend you follow their dietary and lifestyle change advice as best you can and be sure and ask questions. home remedies for tmj

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