Influence of canine vertical position on smile esthetic perceptions by orthodontists and laypersons

Our objectives were to verify the impact of alterations in the vertical position of the maxillary canines in smile esthetic perceptions and to determine whether exposure of the gingival margins directly affects laypersons' and orthodontists' perceptions.

A smile photograph of a male subject showing gingival zeniths was selected, and the canine vertical positions were symmetrically modified in increments of 0.5 mm, creating 4 new images varying from 1.0 mm of intrusion to 1.0 mm of extrusion, with and without gingival exposure. The total of 10 images were evaluated by 60 orthodontists and 60 laypersons, who determined the level of attractiveness of each smile on a visual analog scale.

For both orthodontists and laypersons, the canine vertical position modifications had a statistically significant influence (P <0.0001), and the gingival exposure had no significant influence on the smile esthetic evaluations.

For both groups of evaluators, the most attractive smiles were the standard smile and the smiles with 0.5 mm of intrusion. The less attractive smiles were those with 1.0 mm of extrusion and 1.0 mm of intrusion. Orthodontists were more critical in their assessments. There were no differences in the esthetic evaluations of smiles with and without gingival margin exposure for both groups of evaluators.