Abstract| Volume 46, SUPPLEMENT 1, 227, March 2017

Masticatory myofascial pain and dysfunction treated with intramuscular botulinum toxin injections

      Background: Myofascial pain and dysfunction (MPD) is the most common cause of orofacial pain, and it is broadly categorised by the Diagnostic Criteria for Temporomandibular Disorders into a localised pain pattern and a referring pain pattern. Botulinum toxin (BT) was first proposed as a treatment for MPD some 20 years ago, and today there still exists a debate in the literature regarding its efficacy due to mixed results from clinical trials.
      Objectives: To evaluate the efficacy of BT intramuscular injections in improving MPD, and whether the different subtypes of MPD respond differently to the toxin.
      Methods: 25 consecutive patients treated at our department with BT injections were included in the study. All patients suffered from chronic MPD and were resistant to physical, occlusal, and drug therapy. Primary outcome variable was subjective pain reduction as reported by the patients. Secondary outcome variables were reported analgesic use, and patients’ needs for re-treatment after treatment effects subside.
      Findings: 13 patients suffered from localised MPD and 12 patients suffered from referring MPD. At the two-month follow-up evaluation, nine patients of the localised MPD (70%) reported on significant improvement whereas only two patients of the referring MPD (16%) reported on significant improvement (P = 0.015).
      Conclusion: Intramuscular BT injections proved efficacious in reducing pain in patients with localised MPD while was much less predictable in patients with referring MPD. Future studies should use strict diagnostic criteria to further identify the patients most likely to benefit from this treatment modality.