Accuracy of mesiodistal root angulationprojected by cone-beam computedtomographic panoramic-like images

摘要

Introduction: In this study, we tested the accuracy of the cone-beam computed tomography panoramic(pan)-like image in the projection of mesiodistal tooth angulations. Methods: A plastic typodont with 28 teethin ideal occlusion was fixed in position in a dry human skull for imaging with a NewTom 3G volume scanner(AFP Imaging, Elmsford, NY). Gold standard angular measurements of each tooth were calculated by usinga coordinate measuring machine (CMM) (Faro International, Lake Mary, Fla) and compared with the cor-responding measurement derived from each CBCT pan-like image. Imaging processing was accomplishedwith the proprietary software. Results: Statistically significant differences between the CMM and CBCT pan-like image mesiodistal angular projections were found for 16 of the 28 teeth, although only the mean differ-ence and confidence intervals of teeth 22,12, and 33 (FDI numbering system) were above at the applied toler-ance limit of +-2.5deg (3.675deg with 95% confidence interval of [3.330deg, 4.020deg], 2.006deg [1.339deg, 2.672deg] and 2.179deg[1.800deg, 2.557deg], respectively). The maxillary roots with the exception of teeth 16 and 26 were projected withgreater distal angulations. The mandibular roots with the exception of teeth 44, 47, and 36 were projectedwith greater mesial angulations than the CMM gold standard measurement. Conclusions: Compared withprevious studies on the accuracy of conventional pan radiographs, the mesiodistal angular projection of teethon the CBCT pan-like image is closer to the true mesiodistal angulation. If the practitioner is well acquaintedwith how the information from the CBCT is processed to create the pan-like image, it can be a useful tool forevaluating mesiodistal root angulations.