Diagnostic Ability of Cone-beam Computed Tomography to Evaluate External Root Resorption

The aim of this study was to evaluate the diagnostic ability of CBCT to detect external root resorption. Subjects and External root resorption defects of different sizes and in different locations were simulated in 60 human mandibular incisors. Cavities simulating root resorption defects of small size (0. 3×0. 6 mm)، medium (1. 2×0. 6 mm) and large (1. 8×0. 9 mm) were drilled in the cervical، medial and apical thirds of buccal surfaces. The teeth were divided in random groups and mounted in the mixture of acryle and dryed skull sheep powder. CBCT scan was used to evaluate external root resorption in 180 root thirds by two blinded observer. Statistical analysis was done with Kappa test. Sensitivity of CBCT to detect external root resorption was 89% and the specificity was 99 %. The most defects that was detected were on the medial root thirds and the lowest defects that were detected were on the apical root. The percentage of small defects detection was 80%. CBCT technique is a very good method to evaluate external root resorption with high sensitivity and excellent specificity. It can detect the defects as small as 0. 3mm.