Effect of mesiodistal angulation of the maxillary central incisors on esthetic perceptions of the smile in the frontal view

• Increased axial inclination of maxillary central incisors was judged to be less attractive.
• The judges' perception of the mesiodistal inclination of incisors showed a sex bias.
• Evaluation of lower facial third photographs was more reliable than evaluation of the full face.

IntroductionThe purpose of this study was to analyze the effect of mesiodistal angulation of the maxillary central incisors on the smiling esthetics in young adults.MethodsFrontal smile photographs of a young man and a young woman were digitally modified to produce 28 smile images that were grouped into 4 series. These images were judged using visual analog scales by 52 orthodontists and 61 laypeople. The effects of the judges' professions, subjects' sexes, and photograph framings on the appreciation of smile esthetics with different mesiodistal angulations of the maxillary central incisors were evaluated. The data were analyzed with paired t tests, Dunnett t tests, and independent samples t tests; statistical significance was set at P <0.05.ResultsThe images were ranked less attractive as the mesiodistal angulation of the maxillary central incisors increased during smiling. No relationship was found between the judges' professions and the esthetic evaluations of incisal angulation, but the statistical analysis showed that both the subject's sex and the photograph framing were significant variables (P <0.05).ConclusionsThe mesiodistal angulation of the maxillary central incisors plays an essential role in smile esthetics in the frontal view. When formulating treatment plans, orthodontists should never underestimate the influence of mesiodistal angulation on smile attractiveness.