Esthetic evaluation of dynamic smiles with attention to facial muscle activity

Introduction Numerous studies of smile esthetics have used still photos. Photos, however, do not capture the dynamics of a smile, an element that can contribute to overall smile esthetics. In this study, we assessed the esthetics of dynamic smiles. Methods Four facially balanced female dental students were trained to produce 8 distinct smiles using the facial action coding system. Videos of the models’ whole faces were presented to 2 panels of raters: dental students and nondental undergraduate students. Smile attractiveness was rated using a Web-based survey. Results The smile that used 4 labial muscles was rated significantly better than the smile involving only the risorius muscle ( P P P P  >0.05), perhaps because orbicularis oculi activation altered activations in other muscles in such a way that smile attractiveness was increased in the lower face. Conclusions Smile esthetics increased with increased recruitment of muscles involved in smile production. The results were robust across the models, suggesting that objective rating methods of smile-dynamic esthetics could become an important clinical tool.