Evaluation of smile characteristics in three different sagittal malocclusions before and after nonextraction orthodontic treatment

Introduction: To investigate the smile esthetics variables in three malocclusion classifications of angle to find out if the final smile esthetics was correlated with the initial types of malocclusion. Materials and Methods: This cross-sectional study was performed on 90 adult patients (18-28 years old) with three classes of malocclusion (n = 30 for each class), who were just treated by an orthodontist based on standard edgewise (0.018 inch). A standardized smile mesh analysis was used to evaluate seven smile characteristics. Results: Orthodontic treatment improved all the smile characteristics in the three groups. All groups showed an increase in smile width, smile index, and vertical indices; while, the transverse indices decreased. Significant increase was observed in four smile measurements in patients with Class II malocclusion. Comparing the smile characteristic changes among the three groups revealed that the changes induced by orthodontic treatment were significantly higher in patients with Class II malocclusion. Conclusion: The smile esthetics in all the three types of malocclusion benefited from the orthodontic treatment; however, the changes were more significant in Class II malocclusions. None of the three malocclusion types showed significant difference between the pre- and post-treatment smile characteristics.