Application of Botulinum Toxin in Temporomandibular Disorders: A Systematic Review of Randomized Controlled Trials (RCTs)

Temporomandibular disorders (TMDs) are multi-factorial and polysymptomatic pathologies and their management must be customized for every patient. Numerous therapy techniques are available to treat temporomandibular disorders-related muscular discomfort and persistent orofacial pain. Botulinum toxin (BoNT) has emerged as a popular option for patients with myofascial TMD who do not completely recover from their condition after receiving conservative care and medication. A systematic search of the literature, from January 2000 until 1 April 2022, was performed in the MEDLINE (PubMed), Web of Science, and Lilacs databases. The following search terms combination: (temporomandibular disorders) OR (botulinum) OR (toxin) was employed. A total of 357 articles were initially found in the electronic search. After screening, 11 full-text articles satisfied the inclusion criteria. The Cochrane risk of bias tool (RoB 2) tool, which uses seven domains of bias to assess random sequence generation, allocation concealment, blinding of participants and personnel, blinding of outcome assessment of self-reported outcomes, blinding of outcome assessment of objective measures, incomplete outcome data, selective reporting, and other biases, was employed to analyze randomized controlled trials. The aim of this systematic review of randomized controlled trials is to provide an overview of the use of BoNT for TMDs by comparing the application of BoNT with other therapeutic approaches. BoNT-A could help patients that do not respond to conservative treatments. Low doses are recommended when BoNT-A is considered for persistent orofacial pain related to TMD. Future research should, however, conduct clinical trials with a stricter design. The results of BoNT-A could be confirmed by more randomized controlled trials with larger sample sizes, less bias, and longer follow-up times.