A Prospective Clinical Trail to Evaluate the Role and Efficacy of Botulinum Toxin Type-A for Masseter Muscle Hypertrophy.

[BACKGROUND] Masseter muscle hypertrophy (MMH) is a condition characterized by the enlargement of the masseter muscles, leading to facial asymmetry, pain, and functional issues. Traditionally treated through surgical resection, Botulinum toxin type-A (BTX-A) has emerged as a minimally invasive alternative that reduces muscle bulk and relieves symptoms.

[OBJECTIVE] This study aims to evaluate the efficacy and safety of BTX-A in reducing muscle size, and pain, and improving aesthetic outcomes in patients with MMH.

[METHODS] A prospective clinical trial was conducted with five patients diagnosed with bilateral MMH. Each patient received 30 units of BTX-A per side, with follow-ups at 3 and 6 weeks post-injection. Outcomes were measured using the Masseter Muscle Prominence (MMP) scale, pain scores, and patient satisfaction questionnaires. Descriptive statistics and paired t-tests were used for analysis.

[RESULTS] All patients demonstrated a significant reduction in muscle size, averaging 60% at 6 weeks. Pain scores were reduced by 80-100%, and aesthetic satisfaction scores ranged from 8 to 10. No severe adverse effects were reported, with only mild transient bruising and masticatory fatigue observed.

[CONCLUSION] BTX-A is an effective and safe option for the management of MMH, providing significant aesthetic and functional improvements with minimal side effects. Further research with larger sample sizes and longer follow-ups is recommended to validate these findings.