Nasal ventilation and rapid maxillary expansion (RME): a randomized trial

Summary Objective To assess three rapid maxillary expansion (RME) appliances in nasal ventilation. Trial design Three-arm parallel randomized clinical trial. Methods Sixty-six growing subjects (10–16 years old) needing RME as part of their orthodontic treatment were randomly allocated (1:1:1 ratio) to groups 22 patients receiving Hyrax (H), Hybrid-Hyrax (HH), or Keles keyless expander (K). The primary outcome ventilation (pressure and velocity) secondary outcomes (skeletal, dental, soft tissue, obstruction changes) blindly assessed on the initial (T0) final (T1, 6 months at appliance removal) cone-beam computed tomography (CBCT) data by applying computational fluid dynamics (CFD) method. Differences across with crude adjusted for baseline values confounders (gender, age, skeletal maturation, amount, mucosal/adenoid hypertrophy, septum deviation) regression models alpha = 5%. Results Fifty-four analysed (19H, 21HH, 14K). reduced both pressure (H: ?45.8%, HH: ?75.5%, K: ?63.2%) velocity ?30%, ?58.5%, ?35%) accompanied resolution 26%, 62%, 50%). Regressions accounting severity indicated HH performing better terms post-expansion maximum (P 0.03) 0.04), which was robust confounders. Mucosal/adenoid hypertrophy deviation changes variable, minimal, similar groups. resulted significantly greater increase cross-sectional area (62.3%), anterior (14.6%), posterior (10.5%) widths. Nasal more probable among younger skeletally immature 0.03), male 0.02) without pre-treatment mucosal while associated marginal probability resolution. Conclusions improvement parameters simulated former being favour latter not showing significant differences appliances. Limitation Attrition K group due blocked activation rods possibly leading limited sample identify any existing differences. Harms Replacement expanders finalizing treatment. Protocol protocol published before trial commencement. Registration Australian New Zealand Clinical Registry; ACTRN12617001136392.