title: Effects of botulinum toxin type A on bilateral masseteric hypertrophy evaluated with computed tomographic measurement.
abstract: BACKGROUND
  A paucity of reports exist on the use of botulinum toxin type A injections as an alternative noninvasive treatment for masseteric hypertrophy.
  
  
  OBJECTIVE
  To evaluate the effects of botulinum toxin type A on masseteric hypertrophy using computed tomography.
  
  
  METHODS
  Percutaneous intramuscular injections of botulinum toxin type A of 30 U per side was carried out in 11 subjects with masseteric hypertrophy. The changes in the masseteric muscle volume before and 12 weeks after injection were evaluated using computed tomography. The changes in the lower facial contours on the photographs were evaluated as excellent, good, fair, and no changes.
  
  
  RESULTS
  Nine of the 11 subjects showed a mean reduction of approximately 22% in the masseteric muscle volume. The maximum reduction was 35.4% (range, 8.1% to 35.4%). Nine subjects showed aesthetically good results with a grade of good or excellent at 12 weeks after treatment.
  
  
  CONCLUSIONS
  Botulinum toxin injections are a noninvasive alternative method for treating masseteric hypertrophy.
authors.affiliation: Department of Dental Anesthesiology and Dental Research Institute, Seoul National University College of Dentistry, Korea.
authors.forename: Hyun Jeong
authors.initials: HJ
authors.lastname: Kim
authors.forename: Kwang-Won
authors.initials: KW
authors.lastname: Yum
authors.forename: Sam-Sun
authors.initials: SS
authors.lastname: Lee
authors.forename: Min-Suk
authors.initials: MS
authors.lastname: Heo
authors.forename: Kyle
authors.initials: K
authors.lastname: Seo
mesh_terms: D000328:Adult; D001837:Body Weights and Measures / Q000379:methods; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D006984:Hypertrophy / Q000188:drug therapy; D008297:Male; D008406:Masseter Muscle / Q000000981:diagnostic imaging* / Q000187:drug effects* / Q000473:pathology; D008875:Middle Aged; D009465:Neuromuscular Agents / Q000008:administration & dosage*; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A