Perceptibility and Acceptability of Tooth and Gingival Shade Modifications in Digital Smile Images: A Comparative Study Among Laypeople, General Dentists, and Specialists

<b>Background:</b> This study aimed to evaluate the agreement among different evaluators in assessing smile esthetics from frontal-view photographs of the lower third of the face during smiling, and afterwards to determine thresholds of perceptibility and acceptability of tooth and gingival shade changes on a single modified digital photograph. <b>Methods:</b> Sixty photographs of the lower third of the face of individuals with pleasing smiles were obtained. Evaluator groups included laypeople, general dentists, and specialists in periodontology, orthodontics, and prosthodontics. Esthetic assessment was performed using seven items from the Orofacial Esthetic Scale (OES). One photograph was digitally manipulated by altering the shade of the first maxillary incisor and the gingiva of the right maxillary second incisor. Perceptibility thresholds and acceptability of these modifications were assessed by all evaluator groups. <b>Results:</b> Specialists in periodontology and prosthodontics, although rating 60 photographs as more esthetically pleasing, detected changes in tooth and gingival color earlier and judged such deviations as unacceptable sooner than general dentists and laypeople, particularly for shifts in lighter shades. Laypeople noticed color changes later but classified them as unacceptable almost immediately showing greater tolerance for lighter shades. <b>Conclusions:</b> The study shows that laypeople prioritize brighter tooth shades, whereas dental specialists value a more natural appearance. Specialists' early detection of subtle shade changes and discerning judgments reflects their clinical training and awareness of the challenges in achieving perfect esthetics. In contrast, laypeople, seeking bright teeth influenced by social esthetic norms, noticed changes later but judged them as unacceptable more quickly.