Rapid maxillary expansion in growing patients: correspondence between 3-dimensional airway changes and polysomnography

The aim of the present prospective study was to investigate the effects of rapid maxillary expansion on the airway correlating airway volumes computed on cone beam computed tomography and polysomnography evaluation of oxygen saturation and apnea/hypopnea index.The study group comprised 14 caucasian patients (mean age 7.1 ± 0.6 years) undergone to rapid maxillary expansion with Haas type expander banded on second deciduous upper molars. Cone beam computed tomography scans and polysomnography exams were collected before placing the appliance (T0) and after 12 months (T1). Landmarks localization and airway semiautomatic segmentation on cone beam computed tomography scans allowed airway volume computing and measurements.Increases of total airway volume, oxygen saturation and apnea/hypopnea index were statistically significant. No correlation was found among total airway volume, oxygen saturation and apnea/hypopnea index changes between the examined timepoints.Computing airway volume on cone beam computed tomography allow to measure the amount of air that flows through nasal cavity, nasopharynx and oropharynx while oxygen saturation and apnea/hypopnea index could give information about functional parameters. In the present study all three variables investigated showed statistically significant differences between T0 and T1 but no correlation was found between increases of the different variables tested.