Associations of miniscrew length with long-term skeletal, dentoalveolar, and nasal airflow changes after miniscrew-assisted rapid palatal expansion: A retrospective cohort study

Abstract

Introduction: This study aimed to evaluate the associations between miniscrew length and long-term skeletal, dentoalveolar, and nasal airflow changes after miniscrew-assisted rapid palatal expansion (MARPE). Methods: This retrospective study included 32 adult patients with successful midpalatal suture separation MARPE with either long (n = 15) or short (n = 17) miniscrews. Cone-beam computed tomography scans obtained at pretreatment (T0), postexpansion (T1), and follow-up (T2). Skeletal and dentoalveolar changes were assessed using 3-dimensional landmark analysis. Nasal airflow was evaluated using computational fluid dynamics (pressure-flow ratio and maximum airflow velocity). Between-group and within-group comparisons and correlation analyses were performed. Results: A significant time & times; group interaction observed for inter-processus zygomaticus width (P = 0.002), with the long miniscrew group showing greater skeletal expansion than the short miniscrew group (mean difference at T2-T0: 1.15 mm). No significant group differences in nasal airflow outcomes were observed at any time point. Significant long-term improvements (T2-T0) in pressure-flow ratio and maximum velocity were observed in both groups, exceeding the changes seen immediately after expansion (T1-T0). Correlation analysis revealed that baseline nasal airflow parameters were stronger predictors of functional improvement than the magnitude maxillary expansion. Conclusions: Among successful cases, MARPE with long miniscrews was associated with greater long-term skeletal expansion at the maxillary basal bone level than with short miniscrews. Although nasal airflow improved after MARPE, the magnitude of improvement did not differ by miniscrew length and appeared more related to baseline nasal functional status. (Am J Orthod Dentofacial Orthop 2026;169:654-70)