The two dimensional plain cephalometric radiographs were widely used to assess the post-rapid
maxillary expansion (RME) effect on the naso-pharyngeal airway. However,volumetric changes in
the airway need proper assessment. The aim of this study was to assess the linear and volumetric
changes in the airway pre and post orthodontic RME using cone beam computed tomography
(CBCT). A sample of 12 participants (8 males, 4 females with mean age 14+1.3) who needed RME
for the management of posterior crossbite due to transverse maxillary deficiency was used in this
study. CBCT scans were acquired pre and post maxillary expansion. Linear and angular measurements
were calculated in addition to the volumetric measurements were obtained. There was a
statistically significant increase in inter-molar width and molar tipping. The nasal cavity showed
statistically significant increase in the width of the nasal floor and the lateral nasal width. There was
also statistical significant increase in naso and oropharygeal airway measurements post-expansion.
RME using hyrax appliance increased the nasal floor width, nasal lateral width and the airway volume
at the naso and oropharyngeal level