title: Effect of posterior gingival smile on the perception of smile esthetics.
abstract: OBJECTIVE
  To evaluate and compare the influence of posterior gummy smile on the perception of smile esthetics by orthodontists, general-dentists and laypersons.
  
  
  METHODS
  A frontal photograph of a smile with normal gum exposure was chosen and manipulated digitally using Adobe Photoshop C3 to generate three further images with posterior gum exposure of 4, 6 and 8mm. These four images were assessed by the three evaluator groups: orthodontists (n=40), general-dentists (n=40) and laypersons (n=40). Both orthodontists and dentists had at least ten years professional experience and laypersons were aged between 40-50 years. The proportion of men to women was 20:20 in each group. Evaluators awarded a score to the smile esthetics of each image: 1=acceptable, 2=moderately acceptable, 3=unacceptable. Afterwards, each evaluator placed the four images in order of esthetic preference.
  
  
  RESULTS
  No significant differences (p>0.05) were detected between the three evaluator groups for the photo without posterior gummy smile. The perception of smile esthetics for a the 4mm posterior gummy smile (median for orthodontists=2, general-dentists= 1, laypersons=1), the 6mm (median for orthodontists=2, general-dentists=1, laypersons=1) and the 8mm (median for orthodontists=3, general-dentists=2, laypersons=2) was significantly different between orthodontists and the other two evaluator groups (p<0.0017). The three evaluator groups coincided in placing the image with the 6mm gum exposure in first place in order of esthetic preference.
  
  
  CONCLUSIONS
  Posterior gummy smile influences the perception of smile esthetics more negatively among orthodontists than the rest of the groups.
authors.affiliation: Orthodontics Teaching Unit. University Dental Clinic, Faculty of Medicine and Dentistry, University of Murcia, Hospital Morales Meseguer, 2 planta, C/ Marqués de los Vélez s n, 30008-Murcia, Spain, bravo@um.es.
authors.forename: Alicia
authors.initials: A
authors.lastname: Rodríguez-Martínez
authors.forename: Ascensión
authors.initials: A
authors.lastname: Vicente-Hernández
authors.forename: Luis-Alberto
authors.initials: LA
authors.lastname: Bravo-González
mesh_terms: D000328:Adult; D001290:Attitude; D003813:Dentistry; D004954:Esthetics; D005260:Female; D005881:Gingiva; D006801:Humans; D008297:Male; D008875:Middle Aged; D009970:Orthodontics; D012904:Smiling; D011795:Surveys and Questionnaires