The use of botulinum toxin for the treatment of temporomandibular disorders: Preliminary findings

Purpose: The aim of this study was to evaluate the response of patients wit h temporomandibular disorders to Botulinum toxin A (BTX-A) therapy. Methods: The 15 subjects enrolled in this uncontrolled study were diagnosti cally categorized and treated with 150 units of BTX-A. Both masseter muscle s received 50 units each under eletromyographic (EMG) guidance. Similarly, both temporalis muscles were injected with 25 units each. Subjects were ass essed at 2-week intervals for 8 weeks. Outcome measures included subjective pain by visual analog scale (VAS), measurement of bite force, interincisal opening, tenderness to palpation, and a functional index based on multiple VAS. Results: All mean outcome measures, with the exception of bite force, showe d a significant (P = .05) difference between the preinjection assessment an d the four follow-up assessments. No side effects were reported. Conclusions: BTX-A injections produced a statistically significant improvem ent in four of five measured outcomes, specifically pain, function, mouth o pening, and tenderness. No statistically significant changes were found in mean maximum voluntary contraction or in paired correlation of factors such as age, sex, diagnosis, depression index, or time of onset.