Skeletal changes after rapid maxillary expansion in children with obstructive sleep apnea evaluated by low-dose multi-slice computed tomography

Objective The objective of this study was to evaluate the skeletal effects of rapid maxillary expansion (RME) therapy performed using teeth as anchors, in obstructive sleep apnea (OSA) children, by low-dose computed tomography (CT) of the midpalatal suture opening, maxillary base width, nasal cavities width, first molar angulation and, unlike most studies in the literature, on the pterygoid processes distance. Methods Fourteen children (mean age 8.68 years) with OSA presenting a malocclusion characterized by upper-jaw contraction had 16-Multislice CT (MSCT) scans taken before (T0) and after (T1) RME. All exams were performed using a rigid protocol to ensure reproducibility of image collection over time, with a 16-row MSCT scanner equipped with a Dentascan reconstruction program. Scanning parameters were as follows: scout view in the anteroposterior (AP) and laterolateral (LL); 1.25-mm slice thickness with 0.6-mm collimation from the dentoalveolar and basal areas of the maxilla up to the nasal cavity, parallel to the palatal plane; 80 kV, 100 mA with an 11.25-mm table speed/rotation, rotation time 0.6 s. Matrix size was 512 × 512. Results Opening of the midpalatal suture was demonstrated in all cases. The results showed statistically significant T0 to T1 increments in all treated cases and clear imaging findings. Conclusion Use of three-dimensional (3D)-CT for follow-up studies requires a very rigid protocol to maintain reproducible positions in the scanner over time. The images confirm the real remodeling of craniofacial structure. However, to be valid such an imaging approach needs great attention to reproducibility of anatomic images over time. The changes in volume of the UA, even with a rigid protocol, cannot be affirmed with 3D-CT. There is a need to improve the definition of markers using this imaging approach when performing longitudinal studies; currently this issue is unresolved.