Impact of dental asymmetries on the perception of smile esthetics

Introduction: The purpose of this study was to evaluate the impact of anterior tooth asymmetries on the perception of smile esthetics. Methods: Three pleasant female smiles were digitally altered to simulate several degrees of asymmetry of the gingival margin of a maxillary central incisor, wear of a maxillary canine cusp, and a dental midline shift. Three groups of 50 raters—laypersons, orthodontists, and prosthodontists—evaluated the original and the altered images and used a visual analog scale to score smile esthetics. Results: The threshold of the orthodontists and the prosthodontists for asymmetry of the gingival margin of a maxillary central incisor was 0.5 mm; the threshold for laypersons, who were less perceptive, was 2.0 mm. Wear of a maxillary canine cusp had no esthetic impact for any group of raters. Midline shifts became perceptible when equal to or greater than 1.0 mm for orthodontists and 3.0 mm for prosthodontists; laypersons saw no alteration. Conclusions: Laypersons, orthodontists, and prosthodontists have different perceptions of attractiveness when evaluating gingival margin height of a maxillary central incisor and a dental midline shift. These findings might help dental specialists to consider the patient’s esthetic expectations when planning treatment.