[Botulinum toxin type A treatment of cosmetically disturbing masseteric hypertrophy].

Two patients, a woman aged 21 and a man aged 29, with asymmetrical swellings of both mandibular angles and a painful, heavy sensation in the masticatory muscles (and in the woman also round the maxillary joint), were diagnosed as having hypertrophy of the masseter muscles. Both had the habit of jaw clenching and tooth grinding. Treatment consisted not of the traditional surgical debulking which also allows correction of overdeveloped osseous mandibular angles, but of injections with botulinum toxin type A. Injection of 40-60 IU (product: Botox) per muscle was followed by some atrophy; cosmetically satisfactory results were achieved after repetition of the treatment a few months later. Reduction of muscle volume was confirmed by a quantitative volumetric assessment of MRI scans. In the female patient, the pain also abated.