Three-Dimensional Photography for Evaluating the Effectiveness of Botulinum Toxin Injection for Masseter Hypertrophy

Masseter hypertrophy is a common condition that causes a undesirable square face, and often treated with botulinum toxin type A (BoNTA). Subjective assessments of BoNTA effectiveness vary from physician to patient, necessitating an objective approach for evaluation. This study introduces three-dimensional photography (3DP) for the first time in clinical assessment to evaluate BoNTA treatment for masseter hypertrophy.

Ten patients received 36U of BoNTA at three injection points on each side masseter muscle. 3DP scanner using Artec Eva® was taken at the first, third, and sixth postoperative months for objective evaluation. Patient's self-perceived prominence, patients self-rated satisfaction, and physicians provided 5-grade scores were the subjective indicators.

A significant decrease in left masseter volume at the sixth month (P = 0.002, P = 0.004 at rest and clenching, respectively) was observed. Patient's self-perceived prominence decreased at the first (P = 0.021) and third (P = 0.039) months. Physicians' scores significantly decreased at all postoperative months. No significant changes were noted in the right masseter volume and patients self-rated satisfaction. Patient self-rated satisfaction did not consistently correlate with objective measures, except for left masseter with clenching at the sixth month.

Three-dimensional photography accurately quantifies facial changes post-BoNTA treatment. Despite objective improvements, patient satisfaction may not align consistently. Reliable assessment tools are crucial in cosmetic surgery to manage expectations and prevent disputes.

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