The effects of buccal corridor spaces and arch form on smile esthetics

An attractive, well-balanced smile is a paramount treatment objective of modern orthodontic therapy. The purpose of this study was to determine the effects of buccal corridor spaces (BCS) and arch form on smile esthetics as perceived by laypeople, general dentists, and orthodontists.

Photographs of 20 women treated by 2 orthodontists were collected: 1 group had narrow tapered or tapered arch forms, and the other had normal to broad arch forms. Photographs of 10 untreated women served as a control sample. All photographs showed the subjects smiling. The photographs were digitized and evaluated for BCS. Then, photographs with BCS were altered to eliminate the dark triangular areas, and those without BCS were altered by the addition of dark triangular areas at the lateral aspects of the smile. The altered photographs were randomized into a survey with the 30 original photographs. Three groups of raters (dentists, orthodontists, and laypeople) used a visual analogue scale to rate the photographs.

There was no significant difference in smile scores related to BCS for all samples and for all viewers. Dentists rated broader arch forms as more esthetic than untreated arch forms. Orthodontists rated broader arch forms as more esthetic than narrow tapered arch forms and untreated arch forms. Lay people showed no preference of arch form.

This study demonstrates that the presence of BCS does not influence smile esthetics. However, there are differences in how dentists, orthodontists, and laypeople evaluate smiles and in what arch form each group prefers.