• temporomandibular disorder;
  • chronic tension headache;
  • botulinum toxin

Background.—Temporomandibular disorder (TMD) and chronic tension headaches clinically coexist in many individuals. Generally considered as separate pathological entities, they have been clinically treated by different means.

Objective.—To determine the utility of treatement with botulinum toxin for patients with coexisting TMD and chronic tension type headache.

Methods.—In this open-label study of 60 subjects with chronic TMD, 46 subjects also met the diagnostic criteria for chronic tension headache. All 60 subjects were treated with 150 units of botulinum toxin-A injected into the masticatory muscles, specifically 50 units into each masseter and 25 units into each temporalis muscle.

Results.—Thirty-eight of 60 subjects (63%) reported a 50% improvement in their facial pain during the follow-up period. The subset of 46 subjects with chronic tension headache and TMD symptoms reported a 50% or greater improvement in headache pain as well. The number of headache free days also improved postinjection.

Conclusion.—These results suggest that the masticatory muscles, specifically the temporalis, may be involved in the pathogenesis of this form of chronic tension headache found in association with TMD.