Korean J Orthod.  2014 Nov;44(6):294-303. 10.4041/kjod.2014.44.6.294.

Comparing esthetic smile perceptions among laypersons with and without orthodontic treatment experience and dentists

• An SM
• Choi SY
• Chung YW
• Jang TH
• Kang KH

• KMID: 2273229
• DOI: http://doi.org/10.4041/kjod.2014.44.6.294

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 > or = 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.

Keyword

Esthetics; Photography; Computerized image alteration

MeSH Terms

Crowns
Dentists*
Esthetics
Humans
Incisor
Photography
Tooth
Visual Analog Scale

Figure

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  Figure 1 Shortening of the gingival margin height of the maxillary right central incisor. The numbers in each panel indicate the distance in millimeters.

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  Figure 2 Decreases in the crown width and length of the maxillary left lateral incisor as the gingival margin was moved incisally. The numbers in each panel indicate the distance in millimeters.

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  Figure 3 Canting of the incisal plane as the anterior dental segment was rotated inferiorly on the left side and superiorly on the right side of the subject. The numbers in each panel indicate the distance in millimeters.

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  Figure 4 Shifting of the dental midline. The subject's maxillary dental midline was shifted to the right and the mandibular dental midline to the left in the photograph. The numbers in each panel indicate the distance in millimeters.

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  Figure 5 Graphic illustrations of the questionnaire results. A, Gingival margin height; B, crown width/length; C, incisal plane; D, dental midline.

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