Introduction: Botulinum toxin is a neurotoxin produced by a gram-positive, anaerobic spore-forming bacterium called Clostridium botulinum recently used as an effective and safe line of treatment for the temporomandibular joint disorders (TMDs) through temporarily inhibition of the masticatory muscles. TMDs is a collective non-specific term used to describe disorders that involve the TMJ, masticatory muscles and/or associated structures.
Aim of the Work: A meta-analysis was conducted to evaluate the efficacy of intramuscular Botulinum toxin-A injection (BTX-A) in the treatment of myogenic temporomandibular joint (TMJ) disorders.
Patients and Methods: A systematic literature search was done to identify relevant studies published within the last 25 years on humans. Literature search had been done including PubMed, Medline, Scopus, Web of science, EBSCOhost and Cochrane databases. The study included published medical articles about intramuscular botulinum toxin-A injection in patients suffering from myogenic TMD. The results of the similar studies were pooled in the meta-analysis.
Results: Thirty-nine studies with 1538 participants were included in our systematic review and 23 of these studies were pooled in the meta-analysis. The current study showed that the difference of VAS (visual analogue scale) score at 1 and 3 months associated with intramuscular BTX-A injection (pre- and post-treatment) and BTX-A versus control is statistically significant. The difference of MMO (maximum mouth opening) at 1 and 3 months between BTX-A and control is not statistically significant. The difference of EMG amplitude at 1 month between BTX-A and control is not statistically significant while at 3 months is statistically significant. The change in maximum bite force at 3 and 6 months between BTX-A and control is statistically significant.
Conclusion: The available data favors the efficacy of usage of intramuscular BTX-A injection in cases of myogenic TMD, further randomized controlled studies must be conducted in the future.