title: Gummy smile and botulinum toxin: a new approach based on the gingival exposure area.
abstract: BACKGROUND
  Gummy smile (GS) is an aesthetic disorder for some patients, which can be corrected by injection of botulinum toxin.
  
  
  OBJECTIVE
  We sought to classify GS according to the area of gingival exposure and the respective muscles involved in order to perfect the botulinum toxin injection technique for each patient.
  
  
  METHODS
  Sixteen patients with GS were evaluated before receiving botulinum toxin injections. Based on the area of excessive gum displayed and identification of the muscles involved, 4 different types of GS were identified: anterior, posterior, mixed, and asymmetric. AbobotulinumtoxinA (Dysport, Ipsen Biopharm Limited, Wrexham, UK) was injected using a different injection technique for each type of GS, based on the main muscles involved. With the aid of two computer programs, the area of gum exposed was measured before and after the application of abobotulinumtoxinA, to evaluate the level of improvement.
  
  
  RESULTS
  There was a decrease in the degree of gum display in all patients. The general average improvement achieved was 75.09%. Two patients showed slight adverse effects that were easily corrected with additional doses of abobotulinumtoxinA.
  
  
  CONCLUSIONS
  For this study, there was no sample size calculation and no statistical analysis of the cases.
  
  
  CONCLUSIONS
  The authors conclude that it is important to identify the type of GS and therefore the main muscles involved, so that the correct injection technique can be used. AbobotulinumtoxinA was shown to be effective and safe for use in all types of GS in the present sample.
authors.affiliation: rosemazzuco@hotmail.com
authors.forename: Rosemarie
authors.initials: R
authors.lastname: Mazzuco
authors.forename: Dóris
authors.initials: D
authors.lastname: Hexsel
mesh_terms: D000328:Adult; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage*; D003357:Cosmetic Techniques; D005149:Facial Expression; D005152:Facial Muscles / Q000187:drug effects; D005260:Female; D005881:Gingiva; D006801:Humans; D007273:Injections, Intramuscular; D009465:Neuromuscular Agents / Q000008:administration & dosage*; D012904:Smiling
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A; C542869:abobotulinumtoxinA