Retrospective evaluation of endodontic procedural errors by under- and post-graduate dental students using two radiographic systems

Recognition of factors that cause procedural errors in dental practice and their prevention increase the success rate of endodontic treatment. This study aimed to evaluate the rate of procedural errors in a clinical training setting using conventional and digital radiography systems. In this study, digital and conventional radiographs available in the archives of the Department of Endodontics, Shahed School of Dentistry were used, including 684 conventional radiographs of 171 patients (treated by the 5th and 6th year under-graduate dental students and the 1st and 2nd year post-graduate students) and 852 digital radiographs of 213 patients (treated by the 5th and 6th year under-graduate dental students and the 1st, 2nd, and 3rd year post-graduate students). The errors investigated in this study included missing a canal, canal transportation, ledge formation, apical perforation, furcal perforation, strip perforation, overfilling, under-filling, poor obturation and broken instrument. Radiographs were examined by 3 observers in terms of type of error during endodontic treatment. Once examined, cases that were agreed upon by at least two observers were accepted. In the under-graduate student group, the most frequent errors found in conventional radiographs were poor obturation and under-filling with 8.13% prevalence rate. The most frequent error in post-graduate student group was poor obturation as well with 10.58% frequency. In digital radiographs, in both under-graduate and post-graduate groups, the most frequent error was poor obturation, as well (11.86% in undergraduate and 9.47% in post-graduate groups). The number of error-free anterior teeth (82.05%) was significantly more than that of posterior teeth (65.29%)(P<0.05). Also, 11,96% of anterior teeth had problems in terms of length and quality of filling, while in these respects, 23.5% of posterior teeth were unacceptable, and there was a significant difference in the frequency of these procedural errors between the anterior and posterior teeth (P<0.05). It appears that the educational system in the Department of Endodontics at Shahed School of Dentistry must place a stronger emphasis on the internal anatomy and principles of root canal treatment of the posterior teeth, as well as on the final stage of endodontic treatment (canal filling) for all teeth. It should be noted that an inappropriate canal filling might be secondary to improper canal preparation.