Evaluation the effect of reverse contrast image processing filter on diagnosis of impacted tooth-induced external root resorption, middle portion in cone beam computed tomography, an ex-vivo study

One of the applications of CBCT images is the diagnosis of root resorption of the lateral maxillary teeth, which is often associated with canine impaction.

10 healthy single root teeth that extracted were collected. To simulate external resorption lesions, by using a carbide bur at the lateral surface of the middle third of the tooth root was incised and the teeth were mounted., both before and after teeth preparations, CBCT was prepared from the area with a thickness of 0.125 mm and a distance of 0.125 mm; Then the samples were processed with and without reverse contrast image processing filter and examined by two observers.

Specificity and sensitivity were either complete or very high for both with or without reverse contrast filter modes. The overall accuracy in both cases was high and no significant difference was observed between the two overall accuracy. Also in both with or without reverse contrast filter modes, the sensitivity and overall accuracy in the medium and high resorption groups was much higher than the low resorption group. But the specificity in all groups was equal to 100%.

The images with reverse contrast filter do not increase the detection power compared to unfiltered images, but since no loss of accuracy was observed with this filter, it can be accepted to use as a processing filter.Keywords: External resorption, Root middle portion, Computed beam computed tomography, reverse contrast filter