Smile esthetics: Perception and comparison of treated and untreated smiles

Introduction: Although orthodontic treatment is based primarily on occlusal relationships, greater attention is now paid to enhancing dentofacial characteristics to produce optimal facial esthetics. The purposes of this study were to compare smile esthetics among extraction and nonextraction patients and a control group, assess certain dentofacial characteristics in those groups, and discuss how these features relate to smile esthetics. Methods: Panels of orthodontists, plastic surgeons, artists, general dentists, dental professionals, and parents used a 5-point scale to rate smiling photographs of 25 extraction, 25 nonextraction, and 25 untreated control subjects. Dentofacial characteristics of the 3 groups were obtained from lateral cephalometric analyses, direct biometric measurements, and frontal photographs. Smile esthetics and differences among the 3 groups were subjected to 1-way analysis of variance (ANOVA), and Pearson correlation coefficients were calculated to determine the relationship of the variables to the esthetic score. Results: The mean esthetic scores for the extraction, nonextraction, and control groups were 3.15, 3.12, and 3.26, respectively. Visible dentition width relative to the smile width ratio and intercanine distance relative to smile width ratio were significantly different among the groups, with extraction patients showing a slightly wider dental arch relative to the soft tissue (P < .05). There was also a significant difference in the U1-SN angle among the groups (P < .05), and this variable showed a strong correlation with the esthetic score as did maxillary gingival display (P < .05). However, our study groups could not be differentiated in smile esthetics.