title: Dynamic smile analysis in young adults.
abstract: BACKGROUND
  Current trends in orthodontics place greater emphasis on smile esthetics, yet few studies provide averages and norms for the smile. The purposes of this study were to provide averages for various components of the smile and to compare some of these in orthodontically treated and untreated groups. Also, smiles of patients with and without rapid maxillary expansion (RME) were compared.
  
  
  METHODS
  Video equipment was used to capture smiles in 230 subjects.
  
  
  RESULTS
  The majority of subjects showed on smile flat smile arc, back to the second maxillary premolar, and an 11% buccal corridor. The orthodontically treated group showed a statistically significant more parallel smile arc compared with the untreated group. The RME group had statistically significant less buccal corridor compared with the nonexpanded subjects.
  
  
  CONCLUSIONS
  This study helps to establish dynamic norms for the smile and shows that orthodontic treatment might not flatten the smile arc as previously suggested, and, furthermore, that RME appears to be associated with a decreased buccal corridor.
authors.affiliation: Department of Craniofacial Sciences; Chair, Division of Orthodontics, University of Connecticut School of Dental Medicine, Farmington, CT 06030-1725, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Maulik
authors.forename: Ravindra
authors.initials: R
authors.lastname: Nanda
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D004955:Esthetics, Dental; D005260:Female; D006801:Humans; D008297:Male; D010155:Palatal Expansion Technique; D023861:Photography, Dental; D012016:Reference Values; D012727:Sex Characteristics; D012904:Smiling; D014741:Video Recording