Comparison of the effects of hybrid (tooth-bone supported) and conventional (tooth-supported) rapid maxillary expansion appliances on the dentofacial structures

Aim: The aim of this study is to evaluate and compare the effects of tooth-bone supported hybrid (HRME) and tooth-supported conventional (CRME) rapid maxillary expansion appliances on the dentofacial structures in late adolescents. Methods: The data of this retrospective study consisted of pre- and post-treatment lateral cephalometric graphics, posterio-anterior graphics and orthodontic model records of the patients treated with the need for maxillary expansion. Two groups were formed, in which the same upper jaw expansion protocol was applied with two different maxillary expansion appliances. The first group consists of 15 individuals treated with HRME (9 girls 6 boys, mean age: 16.9 ± 0.42) and the second group consists of 15 individuals (8 girls and 7 boys, mean age 16.74 ± 0.54 years) treated with the CRME appliance. The dental and skeletal measurements were conducted on the records taken from the patients before the treatment (T0) and at the 3rd month (T1) after the treatment. Independent samples t and the Mann-Whitney U tests were used to compare the differences between the two groups. Paired-samples t and Wilcoxon tests were used to compare the measurements at 2 time points for variables. Results: Significant skeletal and interdental expansions were observed in both groups (p <0.05). However, the increase in nasal width measurements in the HRME group (2.24 ± 0.61) was significantly higher than the increase in the CRME group (1.12 ± 0.25) (p <0.01). When the amount of tipping in the premolar and molar teeth was examined, the amount of tipping in the premolar teeth in the HRME group (0.46 ± 0.35) was less than the CRME group (2.46 ± 0.63) (p <0.01). The amount of tipping in the molar teeth was higher (p <0.01) in the HRME group (4.76 ± 0.88) compared to the CRME group (2.9 ± 1.03). Conclusions: Both expansion approaches were found to be effective in the treatment of late adolescent individuals with maxillary deficiency. Keywords: Rapid maxillary expansion, Hybrid RME, Tooth-bone RME.