Lay preferences for dentogingival esthetic parameters: A systematic review.

STATEMENT OF PROBLEM: An objective definition of the characteristics that render a smile esthetically acceptable in the eye of laypeople is lacking.

PURPOSE: The purpose of this systematic review was to identify, appraise, and synthesize the available evidence on the opinion of laypeople regarding the dentogingival characteristics that render a smile esthetically acceptable. The evidence was collected by surveying with standardized digitally modified smile images.

MATERIAL AND METHODS: Four databases were used to search English language studies published between January 1996 and December 2015. This was complemented by a manual search of 8 dental journals. Following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, 2 independent reviewers extracted the relevant characteristics of lay evaluators, the images evaluated, and the outcomes measure. Included studies were assessed in agreement with the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement. Outcomes were treated as a continuous variable, and when more than 1 article provided information on a parameter, the weighted arithmetic mean was calculated.

RESULTS: After 8851 articles were screened, 20 studies were included. Those studies addressed 20 different dentogingival esthetic parameters. The total number of participants interviewed was 3107. According to the Olmos classification, 6 studies had a high level of quality, and 14 studies had a moderate level of quality. The 2 reviewers agreed on all the quality assessments. In the articles reviewed, central incisors clearly played a key role in smile esthetics. Almost all dental, gingival, and occlusal parameters are related to the proportion, shape, and position of central incisors and their relation to the adjacent dental structures.

CONCLUSIONS: The present review provides the estimated thresholds of tolerability and ideal values of smile parameters determined by laypeople. This may guide clinicians in evidence-based diagnosis and the planning of dental esthetic treatments.