Comparison of treatment outcomes of orthodontically treated Class I malocclusion and bimaxillary protrusive patients in the Malay population / Siti Balqish Oon

The aims of this study were to compare the treatment outcomes of orthodontically treated Class I malocclusion and bimaxillary protrusion in Malay population using orthodontics records and questionnaires respectively. 128 Malay patients who met the inclusion criteria were recruited; of which 64 patients were in Class I malocclusion and another 64 patients in bimaxillary protrusion groups. This quantitative cohort study involved plotting of 29 landmarks on two-dimensional lateral cephalometric pre- and post-treatment radiographs using geometric morphometric analysis (GMA). Generalized Procrustes Analysis, Principal Component Analysis, Discriminant Function Analysis, followed by Procrustes ANOVA were performed using MorphoJ and SPSS softwares. Peer Assessment Rating (PAR) Index assessments were carried out using study casts of pre-treatment and post-treatment in both groups. A validated questionnaire was used to determine patients’ satisfaction post orthodontic treatment outcomes. Paired and unpaired t-test and correlation test were applied using SPSS software. Results showed that, with the application of GMA, bimaxillary protrusion group presented more protruded shape of incisor inclination compared to Class I malocclusion group. Both groups had similar skeletal and dental outcomes after treatment completed. In terms of soft tissue, bimaxillary protrusion group exhibited significant improvement in nasiolabial angles, while there was no significant difference in labiomental fold angles in both groups. Regardless of the incisor inclination, the PAR scores were similar for both before and after orthodontic treatment with significant improvement in 99% of the patients. Almost all patients were satisfied with their facial and dental aesthetics after treatment was carried out for both groups. Within the limitations of this study, it can be concluded that the treatment outcomes for both Class I and bimaxillary protrusion cases were satisfactory in terms of clinical improvement and patient satisfaction.