Comparison of the effects of digitally designed miniscrew-assisted hybrid and conventional tooth–tissue-borne rapid maxillary expansion appliances on dentofacial structures

The aim of this study was to compare the effects of conventional tooth–tissue-borne rapid maxillary expansion (KRME) appliances and miniscrew-assisted hybrid rapid maxillary expansion (HRME) appliances on dentofacial structures in late adolescents. A total of 26 patients diagnosed with transverse maxillary deficiency at Uşak University, Faculty of Dentistry, Department of Orthodontics, were included in this study. The patients were divided into HRME and KRME groups. Lateral and posteroanterior cephalometric radiographs, as well as three-dimensional digital models, were obtained before (T0) and after expansion (T1). Statistical analyses were performed using paired t-tests and independent t-tests for parametric data, and Wilcoxon and Mann–Whitney U tests for non-parametric data. A significance level of p<0.05 was adopted. Both appliance groups showed significant increases in maxillary width. In the HRME group, intermolar width (U6–U6) increased by +3.51 mm (p<0.001), while in the KRME group the increase was +3.26 mm (p<0.001). Similarly, significant expansions were observed in intercanine (U3–U3) and interpremolar (U4–U4) distances (p<0.001 in both groups). No statistically significant intergroup differences were found for skeletal or dentoalveolar parameters. Soft tissue measurements also showed no meaningful changes. Hybrid and conventional RME appliances were both effective in correcting maxillary constriction in late adolescents. Although both appliances achieved significant transversal expansion, hybrid appliances did not demonstrate statistical superiority over conventional appliances in this study. Keywords: Rapid maxillary expansion, Tooth–tissue-borne RME, Tooth–bone-borne RME