Effects of Rapid Maxillary Expansion on Upper Airway Volume in Growing Children: A Three-Dimensional Cone-Beam Computed Tomography Study

Abstract

Background: Rapid maxillary expansion (RME) is a common orthodontic procedure that widens the maxillary arch to treat moderate to mild overcrowding and transverse skeletal and dental abnormalities. Orthodontic equipment applies lateral tension on posterior maxilla teeth or palate mucosa to the mid-palatal suture. The maxilla may grow transversely when force is applied at right angles to the mid-palatal suture, which is usually inactive in children and adolescents. This study used cone-beam computed tomography (CBCT) and an authorized upper respiratory airway volume measurement approach to compare RME cohort pharyngeal airway volume changes to healthy controls. Materials and Methods: This retrospective analysis included 52 RME patients and 52 healthy controls. The RME category's expansion regimen entailed twisting the screw of expansion on a tooth-attached Hyrax-type expansion equipment by 0.25 mm daily for at least 14 days. After six months, a few RME participants used fixed orthodontic gear. The comparison group used fixed orthodontic appliances for minor malocclusions without extractions (without RME). CBCT scans from 1021 orthodontic patients who visited a dental hospital between 2012 and 2022 were examined. The registry comprised only anonymized photographs. Volume, minimum cross-sectional area (MCA), molar width, and inter-molar width were measured before and after therapy. Results: The control group had 12227.12 mm3 at T0 and 15805.54 mm3 at T1. The control group's T0-T1 volume difference was statistically significant (p = 0.007). The RME group has 12884.84 mm3 at T0 and 17471.08 mm3 at T1. The RME group had a significant volume difference at T0 and T1 (p = 0.002). The volume RME effect was ±1011.92 and statistically insignificant. (p > 0.05). MCA in the control group was 126.04 mm2 at T0 and 170.61 mm2 at T1. MCA at T0 and T1 in the control group was statistically significant (p = 0.041). RME group MCA was 126.53 mm3 at T0 and 164.69 mm2 at T1. The RME group had a significant volume difference at T0 and T1 (p = 0.002). The MCA, RME effect was 5.92 and statistically insignificant (p > 0.05). Both the control and RME groups had statistically significant volume and MCA differences at T0 and T1. However, the intergroup analysis showed no significant differences across the groups. Conclusion: Tooth-borne RME does not affect upper airway or MCA volume in children compared to controls. Upper airway changes were better with younger skeletal ages before treatment. The findings may aid RME for young children.