Botulinum Toxin Type a for the Management of Masticatory Muscle Pain in Temporomandibular Disorders: A Systematic Review

Abstract

Background: Botulinum toxin type A (BoT-A) has gained significant clinical interest in the management of masticatory muscle pain in temporomandibular disorders (TMD). This may be due to clinical success of BoT-an in treatment of other neuromuscular and refractory chronic pain disorders in the head and neck region, and the limited understanding of the underlying pathophysiology of masticatory muscle pain. Methods: A systematic review was conducted to determine the effectiveness of botulinum toxin type A in the management of masticatory muscle pain in temporomandibular disorders, specifically myalgia, or myofascial pain. Three reviewers separately identified the pertinent literature by searching MEDLINE via PubMed, Web of science and Cochrane databases and reference lists of relevant articles under the inclusion criteria of all studies in English language. Results: Thirteen manuscripts met the inclusion criteria. Among these six were randomized controlled trials (RCT) and seven were case-series investigations. Two out of 6 RCT and all of the 7 case-series investigations have suggested BoT-A therapy being significantly better in management of masticatory muscle pain in TMD. Conclusion: The effectiveness of BoT-A treatment for the management of masticatory muscle pain in TMD has yet to be established. Results of both types of investigations are convoluted by the presence of multiple methodological limitations and heterogeneity in protocol. Botulinum toxin injection therapy appears to effective in certain patients with masticatory muscle pain disorders in TMD. However, there is limited evidence regarding the characterization of participants that would benefit from this therapeutic modality.