Type A botulinum toxin in the treatment of chronic facial pain associated with temporo-mandibular dysfunction.

In an open-label study 41 patients suffering from the muscular form of temporo-mandibular dysfunction were treated with botulinum toxin type A injections into masticatory muscles (average of 200 U on each side) and followed for an average of 6.7 months. Eighty percent of patients improved by a mean reduction of 45% on a visual analogue pain scale. During the observation period, 17% of patients had to receive a second injection because of recurrent pain. Reversible speech and swallowing difficulties occurred in only 1 patient. These encouraging results need to be confirmed by a randomized controlled trial.