In-vitro comparison of 2 cone-beam computed tomography systems and panoramic imaging for detecting simulated canine impaction-induced external root resorption in maxillary lateral incisors

Introduction: The introduction of cone-beam computed tomography (CBCT) in dentomaxillofacial radiology has created new diagnostic challenges, including some potential opportunities for evaluating impacted teeth. The diagnostic accuracy for detection of simulated canine-induced external root resorption lesions in maxillary lateral incisors was compared between conventional 2-dimensional panoramic radiographic imaging and two 3-dimensional CBCT systems. Methods: A child cadaver skull in the early mixed dentition was obtained from the Department of Anatomy, Hasselt University, Diepenbeek, Belgium, with ethical approval. This skull had an impacted maxillary left canine and allowed a reliable simulation. Simulated root resorption cavities were created in 8 extracted maxillary left lateral incisors by the sequential use of 0.16 mm diameter round burs in the distopalatal root surface. Cavities of varying depths were drilled in the middle or apical thirds of each tooth root according to 3 setups: slight (0.15, 0.20, and 0.30 mm), moderate (0.60 and 1.00 mm), and severe (1.50, 2.00, and 3.00 mm). The lateral incisors, including 2 intact teeth, were repositioned individually in the alveolus of the pediatric skull with approximal contacts to the impacted maxillary left canine. Three sets of radiographic images were obtained with panoramic Cranex Tome (Soredex, Helsinki, Finland), Accuitomo-XYZ Slice View Tomograph (J. Morita, Kyoto, Japan), and Scanora 3D CBCT (Soredex, Tuusula, Finland) for each tooth setup. Eight observers examined the 3 sets of 10 radiographs for resorption cavities. Results: The differences in correct detection of simulated root resorption for all cavity sizes were significantly different (P <0.05) between the panoramic and both CBCT systems. CBCT imaging performance was significantly better than that of panoramic radiography for determining root resorption in the categories of slight and severe resorption. Conclusions: These results suggest that the CBCT radiographic method is more sensitive than conventional radiography to detect simulated external root resorption cavities. (Am J Orthod Dentofacial Orthop 2009;136:764.e1-764.e11)