Three-rooted premolar analyzed by high-resolution and cone beam CT

The aim of this study was to analyze the variations in canal and root cross-sectional area in three-rooted maxillary premolars between high-resolution computed tomography (mu CT) and cone beam computed tomography (CBCT). Sixteen extracted maxillary premolars with three distinct roots and fully formed apices were scanned using mu CT and CBCT. Photoshop CS software was used to measure root and canal cross-sectional areas at the most cervical and the most apical points of each root third in images obtained using the two tomographic computed (CT) techniques, and at 30 root sections equidistant from both root ends using mu CT images. Canal and root areas were compared between each method using the Student t test for paired samples and 95 % confidence intervals. Images using mu CT were sharper than those obtained using CBCT. There were statistically significant differences in mean area measurements of roots and canals between the mu CT and CBCT techniques (P < 0.05). Root and canal areas had similar variations in cross-sectional mu CT images and became proportionally smaller in a cervical to apical direction as the cementodentinal junction was approached, from where the area then increased apically. Although variation was similar in the roots and canals under study, CBCT produced poorer image details than mu CT. Although CBCT is a strong diagnosis tool, it still needs improvement to provide accuracy in details of the root canal system, especially in cases with anatomical variations, such as the three-rooted maxillary premolars.