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.


OBJECTIVE
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.


CONCLUSIONS
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.
Private practice particular - Criciúma (SC), Brazil, Criciúma, SC, Brazil.
Fernanda Homem de Mello de Souza
FH
Klein
Universidade Federal do Paraná, Curitiba, PR, Brazil.
Fabiane Mulinari
FM
Brenner
Universidade Federal do Paraná, Curitiba, PR, Brazil.
Maurício Shigeru
MS
Sato
Universidade Federal do Paraná, Curitiba, PR, Brazil.
Fernanda Manfron Batista Rosas
FM
Robert
Universidade Federal do Paraná, Curitiba, PR, Brazil.
Karin Adriane
KA
Helmer
D000328:Adult; D019274:Botulinum Toxins, Type A / Q000627:therapeutic use*; D001938:Brazil / Q000208:ethnology; D005145:Face; D005260:Female; D006801:Humans; D006984:Hypertrophy / Q000188:drug therapy*; D007273:Injections, Intramuscular; D008406:Masseter Muscle / Q000002:abnormalities* / Q000187:drug effects*; D009465:Neuromuscular Agents / Q000627:therapeutic use*; D012904:Smiling / Q000502:physiology; D013997:Time Factors; D016896:Treatment Outcome
D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A