The effect of torque and vertical position of maxillary canine on smile esthetics.

INTRODUCTION: Regarding the key role of the maxillary canine in dynamic occlusion and smile esthetics, this study investigated the relation between smile esthetics and maxillary canine torque and vertical position from the viewpoint of orthodontists, general dentists, and laypersons. METHODS: In this descriptive cross-sectional study, the close-up smile images have been changed using Adobe Photoshop (Adobe Systems, San Jose, Calif). Then, groups of 21 orthodontists, 20 general dentists, and 33 laypersons evaluated the smile attractiveness of the images using a digital version of a visual analog scale. Statistical analysis was performed using SPSS software (version 25; IBM, Armonk, Calif) and Shapiro-Wilk, analysis of variance, and Tukey post-hoc statistical tests. The significance level was set at 0.05. RESULTS: There was no significant difference in the mean score between the 3 groups of observers regarding the changes in the canine vertical position in none of the variations (P >0.05). Regarding variations in torque, there was a significant difference between the 3 groups of observers in the bilateral 5° torque change. (P = 0.020). CONCLUSIONS: Unilateral changes in the vertical position had lower scores, which shows that symmetry is very important in smile esthetics. In addition, laypersons did not find torque changes ranging between -15° to 15° a significant factor in smile esthetics. Overall, some adherence to these values will be acceptable in dental treatments.

Impact of variations in maxillary lateral incisor dimensions on smile esthetics.

INTRODUCTION: Dentofacial esthetics has become an increasingly important topic in recent years among orthodontic patients, so it is suggested that the esthetic perspectives of clinicians and patients be considered when planning orthodontic treatment. The maxillary lateral incisors play a key role in smile esthetics. The purpose of this study was to investigate the effect of dimensional changes of the maxillary lateral incisors on smile esthetics as perceived by orthodontists, general dentists, and laypersons. METHODS: This was a descriptive cross-sectional study. A photograph showing an attractive smile was selected. The dimensions of the maxillary lateral incisors were edited with photograph editing software to represent variations in width, crown length, gingival height, and mesial angulation. Groups of orthodontists, general dentists, and laypersons (n = 16 per group) evaluated the smile attractiveness of the images using the Likert scale according to smile esthetics criteria. Statistical analysis was performed using SPSS software (version 25) and Kruskal-Wallis statistical test. The significance level was set at 0.05. RESULTS: There was no significant difference between mean scores of lateral incisor golden proportion changes, vertical crown length changes, gingival height changes, and mesial angulation changes (P >0.05). All groups found 1 mm more incisally positioned gingival height of lateral incisor than the central incisor and 1 mm more apically positioned incisal edge of lateral incisor than the central incisor to be the most attractive. In the group of orthodontic specialists, the 20° mesial angulation and in the other 2 groups the 10° and 15° mesial angulation had the highest score. CONCLUSIONS: Partial deviations from the ideal esthetic proportions were not detected by laypersons, general dentists, or orthodontists and are acceptable and even attractive from the point of view of patients. Some adherence to these ratios will be acceptable in dental treatments.