Elahe Allahyari - Assistant Professor of Biostatistics, Department of Epidemiology and Biostatistics, School of Health, Social Determinants of Health Research Center, Birjand University of Medical Sciences, Birjand, Iran.
Mahdi Amini - Student of Dentist, Department of Dentist, Student Research Committee, Birjand University of Medical Sciences, Birjand, Iran.
Sediqe Ebrahimipour - Associate Professor of Endodontics, School of Dentistry, Social Determinants of Health Research Center, Birjand University of Medical Sciences, Birjand, Iran

Introduction: Traumas to the teeth can damage the pulp that may require root canal treatment. In addition, the evaluation of trauma errors is very important in every educational system. Therefore, the aim of the present study was to investigate technical errors during root canal therapy and compare these errors among the students who were in their ۴th, ۵th, and ۶th years of their education in the Dental Faculty of Birjand, Iran. Methods: A total of ۴۲۸ documents of root canal therapy performed by dental students who were in the ۴th, ۵th, and ۶th years of their education were randomly selected during ۲۰۱۴-۲۰۱۷. For each tooth, four radiographs, including the periapical images of the initial radiograph, master apical file, master cone, and final obturation radiographs, were reviewed under the supervision of an endodontist. Technical errors investigated included transport, ledge, perforation, underfilling, overfilling, and presence of void and broken instrument. The data were entered into a relevant form and analyzed. The normality was investigated using the Shapiro-Wilk test in the SPSS commercial software (version ۲۲). In the present analysis, because the normality of the data was not confirmed, the Kruskal-Wallis and Mann-Whitney U tests were used, and the Chi-Square test was also utilized at the α-level of ۰.۰۵ to compare the ratio. Results: Technical errors were observed in ۱۴۹ out of ۴۲۸ documents (۳۴.۸%). The numbers of the documents containing technical errors were ۶۰ (۳۰.۶%), ۷۸ (۴۰.۶%), and ۱۱ (۲۷.۵%) associated with the students of the ۴th, ۵th, and ۶th years, respectively. Only one perforation error was observed by the students of the ۵th year. In addition, there was no transport error by the students of the ۴th year. The number of the ledge and overfilling errors presented significant differences by the students of various years (Pledge=۰.۰۱ and Poverfill=۰.۰۰۲). Conclusions: Results of this study showed that ۶۵.۲% of the students had acceptable performance; however, procedural errors were a fairly common finding among the students. Moreover, there were significant differences between students in different years. Pre-evaluation of radiographs and more accurate case selection could promote the quality of root canal therapy among students.

Dental students, Diagnostic Error, Education, Endodontic