title: Comparing esthetic smile perceptions among laypersons with and without orthodontic treatment experience and dentists.
abstract: OBJECTIVE
  The purpose of this study was to examine whether orthodontic treatment experience affects the individual's perception of smile esthetics and to evaluate differences among orthodontically treated laypersons, non-treated laypersons, and dentists by using computerized image alterations.
  
  
  METHODS
  A photograph of a woman's smile was digitally altered using a software image editing program. The alterations involved gingival margin height, crown width and length, incisal plane canting, and dental midline of the maxillary anterior teeth. Three groups of raters (orthodontically treated laypersons, non-treated laypersons, and dentists) evaluated the original and altered images using a visual analog scale.
  
  
  RESULTS
  The threshold for detecting changes in maxillary central incisor gingival margin height among laypersons was 1.5 mm; the threshold of dentists, who were more perceptive, was 1.0 mm. For maxillary lateral incisor crown width and height, the threshold of all three groups was 3.0 mm. Canting of the incisal plane was perceived when the canting was 3.0 mm among non-treated laypersons, 2.0 mm among treated laypersons, and 1.0 mm among dentists. Non-treated laypersons could not perceive dental midline shifts; however, treated laypersons and dentists perceived them when the shift was ≥ 3.0 mm.
  
  
  CONCLUSIONS
  Laypersons with and without orthodontic treatment experience and dentists have different perceptions of smile esthetics. Orthodontically treated laypersons were more critical than non-treated laypersons regarding incisal plane canting and dental midline shifts. Based on these findings, it is suggested that orthodontic treatment experience improved the esthetic perceptions of laypersons.
authors.affiliation: Department of Orthodontics, College of Dentistry, Wonkwang University, Iksan, Korea.
authors.forename: Seong-Mu
authors.initials: SM
authors.lastname: An
authors.affiliation: Private Practice, Jeonju, Korea.
authors.forename: Sun-Young
authors.initials: SY
authors.lastname: Choi
authors.affiliation: Department of Dentistry, CHA Gangnam Medical Center, CHA University, Seoul, Korea.
authors.forename: Young-Wook
authors.initials: YW
authors.lastname: Chung
authors.affiliation: Private Practice, Jeonju, Korea.
authors.forename: Tae-Ho
authors.initials: TH
authors.lastname: Jang
authors.affiliation: Department of Orthodontics, Wonkwang Dental Research Institute, College of Dentistry, Wonkwang University, Iksan, Korea.
authors.forename: Kyung-Hwa
authors.initials: KH
authors.lastname: Kang
keywords: Computerized image alteration; Esthetics; Photography