ABSTRACT
Objective:To analyze the 3D changes of pharyngeal airway in patients with skeletal Class Ⅲ malocclusion after rapid maxillary expansion(RME)and maxillary protraction.Methods:53 patients underwent orthodontic treatment with Hyrax palatal ex-panders and maxillary protraction.Cone-Beam computed tomography(CBCT)scan was taken before treatment(T0),after 1 6 d RME (T1 )and after about 5 month maxillary protraction(T2).Data were reconstructed into 3D model,sagittal and transversal measure-ments,cross sectional areas,volumes of the pharyngeal airway were computed.Results:After RME,the transversal measurements, cross sectional areas,volumes of nasal passage were increased(P <0.05).After maxillary protraction,the 4 nasopharyngeal measure-ments were increased(P <0.05).Conclusion:RME and maxillary protraction may increase pharyngonasal airway.