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. .

Case for diagnosis / Caso para diagnóstico

Pigmentary demarcation lines are physiologically abrupt transition lines from areas of deeper pigmentation to less pigmented areas. They are most often seen in African and Japanese individuals and rarely observed in Caucasians. There are eight types of pigmentary demarcation lines. The one described here, type B, is restricted to women and is associated with pregnancy in non-black patients. This type of pigmentary demarcation line occurs in the posterior aspect of the legs, extending from the perineum to the ankle. Its distribution follows the Voigt's lines, which define the distribution of peripheral nerves. Its pathogenesis remains unknown. Expectant treatment is used, and good results have been reported with the use of Q-switched Alexandrite laser.

Linhas de demarcação pigmentar são linhas fisiológicas que correspondem a transições abruptas entre áreas mais escuras e mais claras. São mais comuns em africanos e japoneses, mas raras em brancos. Há 8 tipos, sendo a aqui descrita, tipo B, restrita a mulheres e relacionada a gestação em não negras. Este tipo de linha de demarcação pigmentar ocorre na face posterior dos membros inferiores estendendo-se do períneo ao tornozelo. Estas se localizam nas linhas de Voigt que são o trajeto dos nervos periféricos. Sua fisiopatogenia é incerta. O tratamento é expectante com relato de bom resultado com Q-switchedAlexandrite laser.