3D CT based rating of unilateral impacted canines

ObjectiveThe aim of this study was to develop a reference system for multislice computed tomography (MSCT) images to determine of the location of impacted teeth in metric terms.Study designThe CT data of 17 patients with unilateral impacted maxillary canines were selected retrospectively from existing MSCT data sets. In a reference coordinate system, defined by anterior nasal spine (ANS), posterior nasal spine (PNS), and A-point, the axis length and the inclination of the canines were determined and impacted and non-impacted canines were compared.ResultsThere were significant differences between the impacted and non-impacted canines (p ≤ 0.0003) for all inclinations and the lengths in the x- and z-axes. The measurement of the inclination and sections of the impacted and non-impacted canine tooth axes showed sufficient repeatability and reproducibility.ConclusionThe coordinate system proved to be suitable for the exact metric localization of impacted teeth.