Effect of Reverse Contrast Image Filter in Detecting Internal Root Resorption in Single Root Teeth in Cone Beam Computed Tomography, an In-Vitro Study

One of the diagnostic problems in endodontic treatment is internal root resorption. Internal resorption is usually asymptomatic. The success of treatment depends on early diagnosis. This study aimed to investigate the effect of a reverse contrast image processing filter in detecting internal resorption of single root teeth.Methods and Materials: In this in vitro study, 45 teeth were cut with a very thin metal disk in the mesiodistal direction and two halves of the teeth were connected and preliminary images were prepared (Control group). In each tooth, a 0.5 mm deep hole was randomly prepared in one of the cervical, middle, or apical positions. Afterward, the two halves of the teeth were connected and the images were taken again. Cone-beam computed tomography images were provided in coronal, axial, and cross-sectional planes, and inverse contrast filter images were evaluated by two radiologists. The results were analyzed using SPSS software version 22 and MedCalc Statistical Software version 14. The significance level for all statistical tests was considered 0.05. According to the first observer, the sensitivity was slightly higher in the filter mode. According to the second observer, the sensitivity and specificity were higher in the case with the reverse contrast filter. The overall accuracy of the observers was higher in the reverse contrast mode than in the unfiltered mode, which was a significant difference (P<0.05). Significantly, images with reverse contrast filters had an effective performance in better detecting internal root resorption.