Efficacy of botulinum toxin in treating myofascial pain and occlusal force characteristics of masticatory muscles in bruxism.

[AIM AND OBJECTIVE] The present study was conducted in patients with bruxism to evaluate the effect of botulinum toxin type A (BTX-A) (Botox, Allergan, Inc., Irvine, CA, USA) in the treatment of myofascial pain and the occlusal force characteristics of masticatory muscles.

[MATERIALS AND METHODS] Twenty-four diagnosed with bruxism were randomly divided into three groups (n = 8) and treated by bilateral intramuscular injection of BTX-A and placebo-treated with saline placebo injections and control group where no injections were given. The clinical parameters such as pain at rest and during chewing were assessed and occlusal force analysis system to measure the distribution of occlusal force in bruxism patients. All the three groups were assessed at baseline time and at 1 week, 3 months, and 6 months follow-up appointments. Descriptive analysis showed that improvements in parameters such as pain at rest; pain during chewing clinical outcome variables were higher in the botox treated group than in the placebo-treated subjects.

[RESULTS] The pain at rest and at chewing decreased in the BTX-A group while remaining constant in the placebo group and control group. There was a significant change in maximum occlusal force in the BTX-A group compared with the other two groups (P < 0.05, post hoc Bonferroni test, no exact P value), and there was no significant difference between the placebo and control groups (post hoc Bonferroni test, no exact P value).

[CONCLUSION] Results from the present study supported the efficacy of BTX-A to reduce myofascial pain symptoms in bruxers, and effective in reducing the occlusal force.