Treating Bruxism with Botulinum Toxin

Treating Bruxism with Botulinum Toxin
Tara Y. T. Chen, Dr. Austin Mardon

Introduction
    Although botulinum toxin is commonly used to minimize wrinkles for cosmetic purposes, it is also used to treat overactive masticatory muscles from a condition called bruxism (Fernández-Núñez et al., 2019). This reduces the frequency of teeth clenching, decreases jaw pain and minimizes headaches in patients (Fernández-Núñez et al., 2019). Although there are a few risks with the procedure, many studies have revealed the therapeutic benefits of botulinum toxin to treat bruxism. 

What is Bruxism?
    Bruxism is characterized by the constant activation of masticatory muscles of the face and is prevalent in 8% to 31% of the adult population (Fernández-Núñez et al., 2019). It is often associated with teeth clenching and grinding (Fernández-Núñez et al., 2019). Although bruxism can occur during any time of the day, many patients unknowingly experience bruxism during their sleep and may wake up with headaches (Asutay et al., 2017). This condition may result in tooth abrasions, tooth sensitivity, fractures, jaw pain and more (Fernández-Núñez et al., 2019). 

What is botulinum toxin?
    Botulinum toxin is a neurotoxin derived from the Clostridium botulinum bacterium and has been used by clinicians since the late 1970s (Asutay et al., 2017; Padda & Tadi, 2021). At neuromuscular junctions, it blocks the release of acetylcholine from cholinergic nerves to prevent synapses within the muscle (Asutay et al., 2017). Specifically, botulinum toxin binds to extracellular receptors at the junction and cleaves a soluble N-ethylmaleimide-sensitive factor attachment receptor (SNARE) protein (Padda & Tadi, 2021). This reversibly prevents acetylcholine release from presynaptic vesicles, blocking muscle activation (Padda & Tadi, 2021). 

Benefits 
    Many studies have revealed that botulinum toxin is effective in treating bruxism. For instance, in a study conducted by Lee et al. (2010), botulinum toxin decreased masticatory muscle activity at night significantly, which decreased the symptoms of bruxism (Lee et al., 2010). Moreover, another study injected 40 mouse units of botulinum toxin into the masticatory muscles of an adult male with nocturnal bruxism (Santamato et al., 2010). After three days, he experienced significantly less neck pain. After four weeks, he experienced a significant decrease in muscle activity and a decrease in action potential amplitude, revealing the beneficial effects of botulinum toxin (Santamato et al., 2010). 
Generally, after injecting the masticatory muscles with botulinum toxin, the initial effects are visible during the first few days and the maximum effects are noticeable at one to two weeks post-injection (Asutay et al., 2017). The effects are temporary and the muscles need to be re-injected every three to four months to maintain the therapeutic effects (Asutay et al., 2017).
    
Risks
    The risks of botulinum toxin is relatively minor. There may be mild pain or bruising at the injection site, which often disappears after a few hours to days (Padda & Tadi, 2021). This can be prevented by applying topical anesthetic creams and using the correct needle size (Witmanowski & Błochowiak, 2020). Local infections may also occur at the injection site but can be prevented by using aseptic techniques to minimize contamination (Witmanowski & Błochowiak, 2020). Unfortunately, botulinum toxin is not administered in patients who are pregnant, breastfeeding, have neuromuscular disorders or botulinum toxin allergies (Padda & Tadi, 2021). 

Conclusion
    Despite a few risks, botulinum toxin is effective in treating jaw pain, headaches and muscle hyperactivity symptoms in bruxism (Lee et al., 2010; Santamato et al., 2010). The neurotoxin’s ability to prevent acetylcholine release at the neuromuscular junction is responsible for these therapeutic effects and will likely continue to be a primary treatment method in the future (Asutay et al., 2017). 

References
Asutay, F., Atalay, Y., Asutay, H., & Acar, A. H. (2017). The Evaluation of the Clinical Effects 
of Botulinum Toxin on Nocturnal Bruxism. Pain research & management, 2017, 6264146. https://doi.org/10.1155/2017/6264146
Fernández-Núñez, T., Amghar-Maach, S., & Gay-Escoda, C. (2019). Efficacy of botulinum toxin 
in the treatment of bruxism: Systematic review. Medicina oral, patologia oral y cirugia bucal, 24(4), e416–e424. https://doi.org/10.4317/medoral.22923
Lee, S. J., McCall, W. D., Jr, Kim, Y. K., Chung, S. C., & Chung, J. W. (2010). Effect of 
botulinum toxin injection on nocturnal bruxism: a randomized controlled trial. American journal of physical medicine & rehabilitation, 89(1), 16–23. https://doi.org/10.1097/PHM.0b013e3181bc0c78
Padda, I. S., & Tadi, P. (2021). Botulinum Toxin. In StatPearls. StatPearls Publishing.
Santamato, A., Panza, F., Di Venere, D., Solfrizzi, V., Frisardi, V., Ranieri, M., & Fiore, P. 
(2010). Effectiveness of botulinum toxin type A treatment of neck pain related to nocturnal bruxism: a case report. Journal of chiropractic medicine, 9(3), 132–137. https://doi.org/10.1016/j.jcm.2010.04.004
Witmanowski, H., & Błochowiak, K. (2020). The whole truth about botulinum toxin - a 
review. Postepy dermatologii i alergologii, 37(6), 853–861. https://doi.org/10.5114/ada.2019.82795

Biographies
Tara Y. T. Chen is a third-year undergraduate student studying medical sciences at the University of Western Ontario in Canada. In the past, she has presented her research on psoriasis treatments at the Western Student Research Conference 2021 and has written several science academic books. 
Dr. Austin Mardon is an assistant adjunct professor at the John Dossetor Health Ethics Centre at the University of Alberta, and the founder and director of Antarctic Institute of Canada.