The Role of Botulinum Toxin A in Treatment of Temporomandibular Joint Disorders: A Review

Temporomandibular joint disorders (TMDs) usually present with symptoms and signs such as pain, mandibular movement, dysfunction, or joint sounds. Botulinum toxin type A (BTX-A) is a biologic toxin which inhibits skeletal muscle through hindering the production of acetylcholine in the nerve endings. This toxin is used for the treatment of hyperactivity of lateral pterygoid muscle and TMD symptoms. This comprehensive review aimed to evaluate the effect of BTX-A injections in the lateral pterygoid muscle on treatment of TMDs symptoms. In this study, online databases including Scopus, Medline, Ebsco, Cochrane, EMBASE, and Google scholar were searched for the keywords "pterygoid muscle" and "Onabotulinumtoxin A". Twenty-four articles were eligible to be enrolled in the study. In 4 interventional studies and 20 descriptive studies, BTX-A was used for the treatment of TMDs. The dosage and number of injections were different in each study; however, the injection methods were relatively similar. Regardless of the type, number of injections, and dosage, injection of BTX-A in lateral pterygoid seems effective in reducing the click sound and other TMJ-related muscle disorders such as pain, hyperactivity, and dysfunction.