Botulinum injection in the masticatory muscles for management of myofascial pain

Objective: The objective of this study was to evaluate the effectiveness of botulinum toxin injection in the masseter and temporalis muscles compared to hard maxillary occlusal splint in management of myofascial pain.
Subjects and Methods: The study was done on forty adult patients suffering from myofascial pain, divided into two groups, Study group patients were injected with botulinum toxin A in masseter and temporalis muscles bilaterally, and control group patients were managed by wearing a hard maxillary occlusal splint. The patients were evaluated by; electromyogram EMG, Visual analogue scale VAS, muscle tenderness, and maximum mouth opening (pain free).
Results: Control group had a higher significant value of EMG than study group after three months. Control group had a higher significant value of VAS than study group after two, three and four weeks, and after two, three and four months. Study group had a higher significant value of VAS than control group after one week and six months. Control group had a higher significant value of muscle tenderness than study group after one and three months, while study group had a higher significant value of muscle tenderness than control group after six months. Study group had a higher significant value of maximum mouth opening (pain free) after two, three and four months. Control group had a higher significant value of maximum mouth opening (pain free) after one week and six months.
Conclusion: Bilateral injections of botulinum toxin in masseter and temporalis muscles was a successful treatment for myofascial pain.