Introduction. The aim of this 3-arm randomized controlled trial (RCT) was to evaluate the effects of tooth tissue-borne (KBME), tooth-borne (Hyrax), and bone-borne (MIDME) rapid maxillary expansion (RME) appliances on sleep quality with polygraphy. Methods. This study was designed in parallel with an allocation ratio of 1:1:1. 46 patients with narrow maxilla and OSAS were included in this study and randomly assigned to three groups: tooth tissue-borne, tooth-borne and boneborne expanders. Participants were congregated from the Department of Orthodontics, Faculty of Dentistry, Izmir Katip Celebi University, Turkey. In all groups, the expansion appliance was activated one-quarter turn twice a day until the desired suture opening was achieved. The primary outcome of this study was the correction of posterior crossbite. Secondary outcomes included polygraphic assessment of sleep parameters. Each subject participated in 1 overnight sleep test with polygraphy before the expansion (T0) and after a 3- month retention phase of treatment (T1). According to the results of polygraphy, 7 parameters; (apnea hypopnea index (AHI), number of apnea and hypopnea, desaturation index, lowest desaturation, average saturation, supin AHI) were examined to evaluate the changes in sleep scores. Kruskal-Wallis analysis and Dunn-Bonferroni test were used for inter-group comparisons and Wilcoxon analysis was used for intra-group evalaution. P<0.05 was accepted statistically significant. Computer-generated randomization was used with group allocation concealed using opaque, sealed envelopes. The outcome assessor was blinded to group assignment. The outcome assessor was blinded; however, it was not feasible to blind either operator or patients.
