# Comparative Assessment of Smile Attractiveness Perception and Treatment Need Across Dental Professionals and Laypersons

## TL;DR

This study compares how orthodontists, dentists, and laypeople judge smile attractiveness and treatment needs, finding that professionals detect minor issues more and recommend treatment more often.

## Contribution

The study introduces a comparative analysis of smile perception across dental professionals and laypersons using a controlled image-based method.

## Key findings

- Orthodontists are more sensitive to minor smile deviations than general dentists and laypersons.
- Treatment recommendations increase with deviation severity, especially for chin and lip asymmetry.
- Laypersons show lower treatment need perception for minor smile deviations compared to professionals.

## Abstract

Introduction: Smile esthetics are crucial in orthodontics; however, orthodontists, general dentists, and laypersons perceive deviations differently, prompting the need for comparative evaluation. This study explored how these groups assess upper midline discrepancies, gingival display, maxillary cant, reduced upper teeth show, asymmetric upper lip elevation, and chin deviation, aiming to determine their combined impact on smile attractiveness and treatment needs while identifying thresholds for clinical intervention to enhance patient-focused care.

Methodology: This cross-sectional study was conducted in the Department of Orthodontics from August 2023 to October 2024. A frontal smile photograph was digitally manipulated to create six series of images (54 images), each with nine variations of upper midline displacement with respect to facial midline (-2 to +2 mm in 0.5 mm increments). Modifications included increased gingival exposure (gumminess), a 5° maxillary cant, reduced upper teeth show, 2 mm asymmetric upper lip elevation, and 2 mm chin deviation. Ninety evaluators (30 orthodontists, 30 general dentists, 30 laypersons) assessed the images using a visual analog scale (VAS) for attractiveness and indicated the need for treatment. Data were analyzed using one-way analysis of variance (ANOVA) for VAS scores and chi-square tests for treatment need, with intra-evaluator reliability assessed using intraclass correlation coefficients.

Results: Orthodontists demonstrated significantly higher sensitivity to minor upper midline deviations (-1.0 mm to 0.0 mm), maxillary cant, and asymmetric upper lip elevation compared to general dentists and laypersons (P < 0.05), with significant intergroup differences in perceived treatment need for all conditions except chin deviation at the ideal midline (0.0 mm). As deviations increased beyond 0.5 mm, perceptions converged, becoming statistically indistinguishable (P > 0.05). Orthodontists recommended treatment most frequently (>90% for 1.5-2.0 mm deviations), particularly for chin deviation and upper lip asymmetry, while laypersons showed the lowest treatment need perception (40%-60% No for minor deviations). Increased gingival display and chin deviation amplified the treatment need across groups, with same-side chin and midline deviations less noticeable than opposite-side deviations.

Conclusions: Professional expertise significantly influenced the detection of subtle smile deviations, with orthodontists advocating treatment more often than laypersons. These findings emphasize the need for tailored patient communication to align clinical interventions with patient expectations and enhance patient-centered orthodontic outcomes.