Effect of Botulinum Toxin Type A Injection on Lower Facial Contouring Evaluated Using a Three-Dimensional Laser Scan

To use three-dimensional (3D) laser scanning to elucidate changes in the external facial contour before and after botulinum toxin type A (BoNT-A) injections.BoNT-A was injected into 15 volunteers as a treatment for lower facial contouring. A total of 25 U of BoNT-A was injected into each side of the masseter muscle bilaterally. On each side, it was injected into two points at the center of the lower third of the masseter muscle separated by 1 cm. The clinical effects of BoNT-A were evaluated by performing 3D laser scans before and 4, 8, 12, and 24 weeks after the injection.The mean values of the volume and widths of the most prominent area at each time point differed significantly before and 4, 8, 12, and 24 weeks after the injection.The volumes and widths of the most prominent areas of the lower face (masseter muscle) were significantly lower 4, 8, 12, and 24 weeks after injecting BoNT-A than before the injection. The mean values of the volume and widths of the most prominent area were 2,176.93 mm(3) and 2.39 mm less, respectively, 24 weeks after the injection than before.