Botulinum Toxin Type A for Painful Temporomandibular Disorders: Systematic Review and Meta-Analysis

This systematic review investigated the effectiveness and safety of botulinum toxin type A (BTX-A) for painful temporomandibular disorders. We searched for randomized controlled trials (RCTs) in 10 databases, from inception to February 12, 2019 (MEDLINE, EMBASE, CENTRAL, LILACS, BBO, Web of Science, Scopus, ClinicalTrials.gov, WHO and OpenGrey). We included 12 RCTs that compared BTX-A versus inactive or active interventions. BTX-A was slightly more effective than placebo for pain reduction at 1 month: mean difference -1.74 points (0-10 scale), 95% confidence interval -2.94 to -.54, 3 RCTs, 60 participants, I-square (I²) = 0%. However, there were no significant differences at 3 and 6 months. BTX-A was similar to no treatment for pain reduction at 3 and 6 months. BTX-A was more effective than conventional treatment and low-level laser therapy for pain reduction at 1, 6, and 12 months, but less effective than facial manipulation for pain reduction at 3 months. BTX-A was not associated with a significant increase in the risk of adverse events. The quality of the evidence was low, and results are insufficient to support the use of BTX-A for painful temporomandibular disorders. High-quality RCTs are needed to increase confidence in effect estimates. PERSPECTIVE: BTX-A for painful temporomandibular disorders appears to be well tolerated. For pain reduction, BTX-A is slightly more effective than placebo only at 1 month; conventional treatment and low-level laser at 1, 6, and 12 months. Low-quality evidence limits the applicability of these findings and precludes recommendations for practice.