The effect of botulinum toxin A (BTX-A) injection in the lateral pterygoid muscle in treatment of temporomandibular joint clicking

Abstract

Temporomandibular disorder is known as a variety of disorders that cause pain in temporomandibular joint (TMJ), impair in the motion of the mandible and also produce a sound in this joint known as E?click . Type A botulinum toxin is a biologic poison that causes skeletal muscle relaxation due to blocking of acetylcholine production in the terminal of nerves. This poison has been used in the treatment of hyperactivity of lateral pterygoid muscle. In our study, we made an attempt to collect and evaluate information of all studies that have tried to use botulinum toxin injection into the lateral pterygoid muscle as a therapeutic method in the treatment of temporomandibular disorders as a systematic review. Methods and materials: We searched Scopus, Medline, Ebsco, Cochrane, EMBASE and Google scholar with the certain keywords such as E?onabotulinumtoxin A and E?pterygoid muscle . After collecting of all studies and considering our inclusion and exclusion criteria, there were 24 studies eligible for inclusion in our study. Results: In 4 interventional studies and 20 descriptive studies included in this study, use of botulinum toxin in the treatment of temporomandibular disorders has been recommended. Each study has used a different dose of injection (12.5-200 U), with almost the same number of injections and method (intraorally and use of electromyography in many patients). Conclusion: The final interventional studies included in the present study were quasi-experimental studies; Therefore, they were not sufficiently effective in controlling the confounding factors. As a result, in the final conclusion of our study, there was no hard evidence for the efficacy of injection of botulinum toxin A into lateral pterygoid muscle in decreasing the click sound and recovering from other muscular disorders of the TMJ, including pain, hyperactivity, dysfunction, etc. However, since these effects were mentioned in the studies included in our review, such effects seem probable. Further unbiased randomized clinical trials might provide more reliable evidence in relation to the effect of this treatment modality.