Cone-beam computed tomography can be an important aid in the diagnostic process. The purpose of this study is to determine if CBCT allows the dental provider to interpret the images in a reliable manner. Methods: CBCT images of 120 permanent teeth were interpreted by 2 board certified endodontists, 7 endodontic residents, and 2 general dentists. The observers determined whether or not a specific tooth had normal periapical tissue, widened periodontal ligament (PDL) space, or a periapical radiolucency (PARL). Scans were viewed using i-Dixel (Kyoto Japan) software multi-planar reconstructed volumes. The images were examined on a Dell CPU with the same 27 inch screen monitor for all evaluators. To assess the agreement between providers ratings of 120 images, two measures were calculated. First, an agreement index (Pi) was calculated for each image, and an average of these scores was obtained. Since this average includes agreement due to chance, Fleiss Kappa statistic (a chance-adjusted index of agreement for multi-rater categorization of nominal variables) was also calculated. Results: An agreement index was calculated for each image and an average of these scores was obtained. Due to chance a Fleiss kappa statistic was used to measure agreement among multiple observers. 51.4% indicates intermediate/good agreement. The average of the individual image agreement index scores was 68.8%. Out of 120 total images only 27.5% had perfect agreement. 80% of images had at least 7 out of 11 providers agreeing. Conclusion: The results demonstrate that the interpretation of a CBCT volume is subjective. However, inter-observer agreement with CBCT images is higher than two dimensional film or digital periapical radiography.