Abstract
OBJECTIVE: To investigate the frequency of midpalatal suture separation with tooth-and-bone-borne (TBB) and bone-borne (BB) miniscrew-assisted rapid palatal expansion and to compare their skeletal and dentoalveolar effects in young adults. METHODS: This retrospective study included 34 patients (14 male and 20 female) who underwent palatal expansion divided into two groups: TBB group (n = 15; mean age, 22.3 years) and BB group (n = 19; mean age, 21.7 years). Cone-beam computed tomography images were acquired before treatment (T0) and after a 3-month consolidation period (T1). The primary outcomes were the frequency of midpalatal suture separation (%) and skeletal and dentoalveolar changes after expansion. The secondary outcome was the dental expansion ratio (%). RESULTS: Midpalatal suture separation was observed in 73.3% (11/15) and 73.7% (14/19) of patients in the TBB and BB groups, respectively. Both groups showed comparable increases in skeletal measurements. However, the TBB group demonstrated greater dentoalveolar expansion than the BB group. In addition, the TBB group exhibited greater dental inclination and a greater reduction in the buccal alveolar bone thickness than the BB group. Furthermore, the dental expansion ratio was significantly higher in the TBB group (65.0%) than in the BB group (35.7%, P < 0.001). CONCLUSIONS: Both TBB and BB achieved successful midpalatal suture separation in young adults, with success rates of 73.3% and 73.7%, respectively. Moreover, skeletal expansion outcomes were comparable between the groups. However, dental expansion was greater in the TBB group than in the BB group, with a greater increase in dental inclination.