Skeletal, Dental and Smile Esthetic Changes in Skeletal Class II patients Treated with Maxillary Premolar Extraction and Non-extraction Mechanotherapy–A Cross-sectional Study

Introduction: This study aimed to compare smile aesthetics in skeletal class II subjects who underwent fixed appliance therapy with maxillary premolar extraction (PME) and non-extraction fixed mechanotherpy (NEF), and to evaluate the perception of esthetic smiles among three panels of raters. Materials and Methods: A cross-sectional study was conducted on a sample of 36 skeletal class II subjects ideally planned for PME. The study subjects were divided into two groups: 18 cases treated with PME and 18 cases treated with NEF at the patient’s request. Seven smile variables were measured on pre- and post-treatment frontal close-up smile photographs of two groups. Ten laypersons, general dentists and orthodontists evaluated those photographs on visual analogue scale. An Independent t-test was applied to compare the post-treatment smile variables and scores between the groups. Results: In a comparison of post-treatment photographs between the groups, a statistically significant difference was found in the values of arch form index (AFI) (p = 0.01) and overjet (p = 0.006). A statistically significant difference was observed in the perception of smile aesthetics among the raters (p < 0.001). Conclusions: Patients ideally planned for maxillary premolar extraction when treated with non-extraction fixed mechanotherapy using class II elastics did result in dental and soft tissue improvement but were not able to achieve ideal values at the end of treatment. Laypersons and dentists preferred smile aesthetics in maxillary first premolar extraction treatment, whereas all three panels of raters gave higher scores to non-extraction fixed mechanotherapy in terms of improvement in the smile.