Lower facial remodeling with botulinum toxin type A for the treatment of masseter hypertrophy

Background: masseter hypertrophy has been treated with botulinum toxin injections because of esthetic complaints especially in asians.objectives:the goal of the present study was to evaluate the efficacy of abobotulin toxin use in masseter hipertrophy treatment in brazilians.methods: ten brazilian female patients with masseter hypertrophy were subjected to injections of 90u of abobotulinum toxin a applied on each side respecting the safety zone stabilished in literature and were followed up for 24 weeks.results: when analyzing the coefficients between measures of middle and lower third of the face obtained from standardized photographs,an increase was observed,with statistical significance at 2 weeks (p=0.005) and 12 weeks (p=0.001). the progression of lower third reduction was 3.94%,5.26%,11.99%,and 5.47% (2,4,12,and 24 weeks respectively). all patients showed improvement in bruxism after treatment. observed adverse effects were masticatory fatigue,smile limitation,and smile asymmetry.conclusion: the use of abobotulinum toxin a for masseter hypertrophy is effective in brazilians and reached its maximum effect of facial thinning at 12 weeks. smile limitation had a higher incidence compared to that reported in the literature and may result from risorius muscle blockage caused by toxin dissemination. despite its side effects,80% of the patients would like to repeat the treatment. © 2014 by anais brasileiros de dermatologia.