Square face is on of the facial features common among Asians. It is characterized by a prominent and broad cheek and angular jaw. The angular shape of the jaw is caused by 2 main factors, a strong and prominent mandibular bony angle and a prominent masseter muscle. To smoothen the contour of the jaw at the angle, conventional surgery to reduce the angle of the mandibular bone and reduction of the masseter muscle is done. This is a complex surgery, which has significant downtime and risk.

B. Toxin can be used to slim down the angular shape of the jaw without surgery by reducing the bulk of jaw (masseter) muscles. B. Toxin prevents the masseter muscle from actively contracting during mastication, chewing or grinding of the teeth unconsciously in the night. By reducing the activity of the masseter muscle, it relaxes and becomes less bulky due to disuse atrophy. The result is a smoother contour of the jawline at the angle. The treatment does not affect normal eating, chewing or swallowing because not the entire muscle is “paralysed” and there are many other muscles involved in the process eating. In order to maintain the reduction, once or twice a year treatment to the muscle jaw is recommended.