Effects of Bonded Rapid Palatal Expansion on Nasal Cavity Volume

Objectives: The aim of this study was to evaluate the volumetric changes of the nasal cavity from bonded rapid palatal expansion (RPE) in children using Cone Beam Computed Tomography (CBCT) images. Methods: Twenty nine children, both male and female, (mean age: 9:9 years) who required RPE as part of orthodontic treatment were included in this study. CBCT images using the I-CAT® machine (Imaging Sciences International, Hatfield, PA) were obtained as part of pretreatment orthodontic records (T1) and at the completion of RPE (T2) for all patients. The mean jack screw opening of the expansion measured as 8 mm (range: 6.5-9.4 mm). On each CBCT image, the skull was oriented and standardized in the frontal view with the floor of the orbits parallel to the floor, and in the right and left lateral views with the Frankfort horizontal line (porion to orbitale) parallel to the floor. For each patient, the nasal cavity volume was analyzed at T1 and T2 using the Dolphin 3D Imaging version 11 (Dolphin Imaging and Management Solutions®, Chatsworth, CA). The nasal cavity area was defined as the airway space within the boarder points: sella, nasion, tip of nose, subnasale, ANS, PNS and basion in the saggital slice view. In the axial view, boundaries were placed at slice level of the tip of the nose at: the posterior border of each condyle, the most lateral parts of the right and left zygomatic processes and the tip of the nose. A two-tailed paired t-test was conducted to determine if the changes were statistically significant in nasal cavity volume from T1 to T2. Results: The nasal cavity volume increased significantly as a result of RPE (P < .05) with the average change of 8%. Conclusion: RPE significantly increased the nasal cavity volume in children.