Investigation of the Effects of Tooth-Borne, Tooth-Bone-Borne and Bone-Borne Rapid Maxillary Expansion Appliances on the Nasomaxillary Complex Using CBCT

Objective: This study aimed to investigate the effects of tooth-borne, tooth-bone-borne, and bone-borne rapid maxillary expansion (RME) on the nasomaxillary complex in individuals with maxillary transverse constriction using cone-beam computed tomography (CBCT), and to compare the outcomes of these expansion modalities. Methods: CBCT images from 45 patients (aged 10-17 years) with maxillary transverse constriction who were treated with RME were evaluated. Patients were divided into three groups according to the appliance used: tooth-borne (Hyrax), tooth-bone-borne (hybrid), and bone-borne. CBCT records were obtained at three time points: before treatment, after active expansion, and after a 3-month retention period. Dentoalveolar and skeletal measurements were performed on the CBCT images. Intergroup comparisons were conducted using one-way ANOVA and Kruskal-Wallis tests, while intragroup comparisons were performed using repeated-measures ANOVA and Friedman tests. Results: CBCT evaluation revealed no statistically significant intergroup differences in dental and skeletal measurements. However, all RME groups showed significant increases between time points, most of which were maintained after the retention period. In the mandible, increases in intercanine, interpremolar, and intermolar widths, observed during the active expansion phase, partially relapsed or lost their statistical significance following retention. Conclusion: All RME modalities produced significant skeletal and dental expansion in the maxilla, with the bone-borne appliance showing greater skeletal effects than the hybrid and tooth-borne appliances.