Botulinum toxin: new treatment for temporomandibular disorders

Background: Temporomandibular disorders (TMDs) affect the face and jaws, and cause chronic pain and dysfunction in many people. As in other conditions involving the musculoskeletal system, controlling the myogenous component is an integral part of treatment. In this study, we evaluated subjective and objective responses to treatment with botulinum toxin A (BTX-A) in a group of 46 patients with TMDs. Methods: 46 subjects with TMD were enrolled in this uncontrolled study and treated with BTX-A 150U. Both masseter muscles were injected with 50U each and both temporalis muscles with 25U each under electromyographic guidance. Subjects were assessed at two-week intervals for eight weeks. Outcome measures included subjective assessment of pain by visual analogue scale (VAS), measurement of mean maximum voluntary contraction (MVC), interincisal oral opening, tenderness to palpation, and a functional index based on multiple VAS. Medians of the data were taken for each outcome measure at each time point and subjected to Duncan’s multiple range test. Results: There were significant (P