Effect of botulinum toxin A on pain, bite force, and satisfaction of patients with bruxism: A randomized single-blind clinical trial comparing two protocols

Purpose: The current study aims to evaluate bite force, perception of orofacial pain, and treatment satisfaction of patients with bruxism using two protocols of botulinum toxin A (BTX-A) injections. Material and Methods: Two groups of patients seeking bruxism treatment and presenting bilateral orofacial pain of muscle origin were randomly created according to BTX-A injection sites: masseter muscle only, bilaterally (3 points in each muscle, 10 U per point), and masseter and temporal muscles (3 points in each masseter muscle and 2 points in each temporal muscle, 10 U per point). The patients were evaluated preoperatively and longitudinally at 15, 90, 120, and 180 days by the use of visual analog scales for pain and treatment satisfaction and a gnathodynamometer for bite force recording. Results: The final sample included 10 participants in each group. Both groups presented mitigation of pain at 15, 90, 120, and 180 days in comparison with baseline; however, reduction in the posterior bite force was noted only at 15, 90, and 120 days. Quite high treatment satisfaction was reported from both groups at 15, 90, 120, and 180 days. No differences were observed between the groups in all evaluations and study periods. Conclusion: In general, considering pain relief, reduction in bite force, and treatment satisfaction, both protocols of BTX-A seem to be somewhat equally effective in the short-term management (up to 120 days) of bruxism.