Oral and maxillofacial radiologyThree-dimensional assessment of impacted canines and root resorption using cone beam computed tomography

ObjectiveThe objective of this study was to localize impacted canines in 3 dimensions and determine the most common location of impaction using cone beam computed tomography (CBCT). We also assessed root resorption of adjacent teeth. The cusp tip of each impacted canine was located and digitized using Dolphin 3D imaging, after viewing sagittal, coronal, and axial views. The position on the occlusal plane where the normally erupted canine cusp tip should be located was used as a control reference point. The degree of impaction was defined by the difference between the impacted canine cusp tip and reference cusp tip positions.Materials and MethodsCBCT scans of 29 consecutive individuals with impacted canines undergoing orthodontic treatment at the UCSF Orthodontic Clinic were included in this study.ResultsThe average degree of mesial impactions was 10.1 mm, of distal impactions was 4.2 mm, of facial impactions was 4.16 mm, of palatal impactions was 1.8 mm, and of gingival impactions was 10 mm; 40.4% had no root resorption, 35.7% showed slight root resorption, 14.2% showed moderate resorption, and 4% showed severe root resorption of the adjacent lateral incisor.ConclusionWe reliably assessed the position of impacted canines in 3 dimensions using CBCT, thereby improving accuracy of location and facilitating precise surgical and orthodontic management. In our study 40.4% had no root resorption, 35.7% showed slight root resorption, 14.2% showed moderate resorption, and 4% showed severe root resorption of the adjacent lateral incisor. The most frequent location of impacted canines was palatal, mesial, and gingival.