Perception of smile attractiveness of adolescent girls with severe maxillary anterior crowding: a web-based, comparative study between Japan and the United States

Abstract

ABSTRACT Purpose In Japan, severe maxillary anterior crowding (MxAC) has historically been considered a positive feature of a girl’s smile, but no comparative studies with other countries have been conducted. Therefore, the present study compared the perceptions of smile attractiveness of adolescent patients with MxAC between the general populations in Japan and the United States using a web-based, questionnaire survey. Materials and methods Smiling frontal facial images of six adolescent patients with severe MxAC photographed before and after treatment were selected. A total of 200 age- and gender-matched participants were selected from the general populations in Japan and the United States as the JP and US groups, respectively. The attractiveness of images was evaluated using a Likert scale, and the number of images positively evaluated among 6 models was calculated as the preference score. Higher preference score indicated more positive attitudes towards those images. The preference scores were compared between the groups, and between before and after orthodontic treatment, as well as between age and gender subgroups for both groups. Results The preference scores were significantly higher before treatment and significantly lower after treatment for the JP group than for the US group. The preference score for before treatment in females was significantly higher in the JP group than the US group. The preference score for after treatment in adults was significantly lower in the JP group than the US group. Conclusions The smiling facial images of adolescent girls with MxAC are more preferred in Japan than in the United States, but this association is reversed after orthodontic treatment.