Comparison between two techniques in studying of root canal types

Objectives: To evaluate the agreement of radiovisiography (RVG) and the clearing techniques in the study of the root canal types,and to assess inter- and intra-examiner agreement at different times using RVG system.Methods: One hundred recently extracted human maxillary first premolars were used. Standard periapical RVG images were taken from a buccolingual and mesiodistal direction. Then the specimens were accessed, injected with dye, demineralized, dehydrated, and finally were cleared. The images were evaluated based on the root canal types by two independent trained endodontists (examiner A and B) twice at an interval of 2 weeks. And the 100 transparent teeth were examined under x5 magnification using a dental operating microscope by another experienced endodontist, and the dates of root canal types were collected. Results: The Kappa values between two times of each examiner were 0.7704 and 0.7725. The Kappa values for the agreement between the two examiners were 0.537 and 0.4793, respectively. The Kappa values for the agreement between the examiner A and the clearing technique were 0.3793 and 0.3384, while the Kappa values between the examiner B and the clearing technique were 0.2472 and 0.2184, respectively.Conclusions: The agreement of intra-examiner was substantial, and the agreement of inter-examiner was moderate. But the agreements between either RVG examiner and the clearing technique were poor, indicating limitation in the value of RVG system when studying certain aspects of the root canal system. The resolution of the RVG system should be enhanced.