Effects of bonded rapid maxillary expansion and miniscrew-assisted rapid palatal expansion on craniocervical posture, sagittal pharyngeal airway dimensions, and hyoid bone position

This study aimed to compare the effects of bonded rapid maxillary expansion (RME) and miniscrew-assisted rapid palatal expansion (MARPE) on skeletal measurements, craniocervical posture, sagittal pharyngeal airway dimensions, and hyoid bone position using lateral cephalometric radiographs. This retrospective cohort study included 60 patients with transverse maxillary deficiency treated with bonded RME or MARPE. The bonded RME group included 30 patients (17 females and 13 males) and the MARPE group included 30 patients (16 females and 14 males). Lateral cephalometric radiographs obtained before treatment (T0) and 6 months after completion of active screw activation (T1) were analyzed using ImageJ software. Generalized estimating equation models were used for repeated-measures comparisons, and chronological age was included as a covariate. After adjustment for age, no significant group × time interaction was observed for any skeletal measurement. ANB showed a significant time effect, whereas SNA, SNB, SN–GoGn, NSL/NL, and FH/ML did not show significant time-dependent changes. No significant group, time, or group × time interaction effects were detected for sagittal pharyngeal airway or hyoid measurements. Significant group × time interactions were observed for NSL/OPT, NSL/CVT, and CVT/HOR, indicating different craniocervical postural change patterns between the groups. In skeletal Class I patients with transverse maxillary deficiency and normal vertical growth patterns, bonded RME and MARPE showed comparable skeletal, sagittal pharyngeal airway, and hyoid outcomes after age adjustment. The absence of significant sagittal airway and hyoid changes should be interpreted within the limits of two-dimensional cephalometric assessment. The craniocervical posture findings should be considered exploratory and interpreted cautiously.