Botulinum toxin therapy for temporomandibular joint disorders: a systematic review of randomized controlled trials

The objective of this study was to undertake a systematic review to assess the efficacy of botulinum toxin therapy (BTX) for temporomandibular joint disorders (TMDs). A comprehensive search of major databases through PubMed, EMBASE, and Cochrane CENTRAL was conducted to locate all relevant articles published from inception to October 2014. Eligible studies were selected based on inclusion criteria and included English language, peer-reviewed publications of randomized controlled trials comparing BTX versus any alternative intervention or placebo. Quality assessment and data extraction were done according to the Cochrane risk of bias tool and recommendations. The entire systematic search and selection process was done independently by two reviewers. Five relevant study trials were identified, involving 117 participants. Two trials revealed a significant between-group difference in myofascial pain reduction, another trial that compared BTX with fascial manipulation showed equal efficacy of pain relief on TMDs, while the remaining two trials showed no significant difference between the BTX and placebo groups. Because of considerable variations in study methods and evaluation of results, a meta-analysis could not be performed. Based on this review, no consensus could be reached on the therapeutic benefits of BTX on TMDs. A more rigorous design of trials should be carried out in future studies.