Changes of the Frontal Sinus in Adolescents Analyzed Using CBCTs

Objectives: The purpose of this study was to analyze changes to the frontal sinus over time in adolescents (age 11-17) using cone-beam computed tomography (CBCTs).
Methods: The frontal sinuses of 60 patients were analyzed. Each patient had images taken 19-24 months apart (at the start and beginning of orthodontic treatment). All patients were from the Graduate Orthodontic Clinic patient pool at the University of Alberta. CBCTs were visualized and evaluated using AVIZO®. The borders of the sinuses were outlined manually to construct 3D models and analyzed to determine the change in dimension over time. Seven CBCTs not used in the study were analyzed to determine reliability of the landmarking procedure in AVIZO®. Each was analyzed three times leaving a week in between trials. ANOVA, Bonferroni post-doc test and t-test were used to compare the datasets.
Results: Datasets that were obtained for the same images were 89% similar indicating that the procedure was reliable. The changes in shape of the frontal sinuses between the serial images were minimal at 3.5mm (sd 2.3) while the changes in volume were at 24% (sd. 22.5) indicating an increase in size but no change in shape.
Conclusions: The frontal sinus changes minimally in shape over time, whereas the volume increases extensively. Therefore, as a whole, the frontal sinus can be used as a stable structure in terms of shape superimpositioning but not adequate in terms of size.