Introduction: The aim of this 3-arm parallel trial was to compare the effects of tooth-borne (Hyrax), tooth tissue-borne (KBME) and bone-borne (MIDME) rapid maxillary expansion (RME) appliances on nasal airway with acoustic rhinometry (AR).~Methods: Fourty-six 12- to 14-years-old patients with narrow maxilla were randomly allocated into 3 study groups according to the type of RME appliance: tooth-borne, tooth tissue-borne and bone-borne. Participants were recruited from the Department of Orthodontics, Faculty of Dentistry, Izmir Katip Celebi University, Turkey. During the RME treatment, the same protocol was applied to all patients and the expansion screws were activated twice a day (0.4 mm/day). Computer-generated randomization was used with group allocation concealed using opaque, sealed envelopes. The outcome assessor was blinded; however, it was not feasible to blind either operator or patients. The primary outcome of this study was the correction of posterior crossbite. Secondary outcomes included AR assessment of nasal airway dimensions as nasal volume, the minimal cross-sectional area (MCA) 1 and 2. AR measurements were obtained before treatment (T0), after active expansion (T1), and at 3 months-follow-up (T2). One-way analysis of variance (ANOVA) and a Bonferroni test was used for inter-group comparison and two-way ANOVA was used for intra-group evalaution.
Rapid maxillary expansion (RME) is an orthodontic treatment based on the principle of opening the midpalatal suture with the effect of orthopedic forces. The aim of this randomized clinical study was to evaluate and compare the effects of tooth-borne, tooth-tissue borne, and bone-borne rapid maxillary expanders on nasal airway by using AR. The null hypothesis was that there is no difference for the effect on nasal airway between the appliances.