## 4 Discussion  
The findings of the present study suggest that the diagnostic accuracy of digital periapical radiography is higher than that for CBCT for detecting separated endodontic files, while they suggest that CBCT has a higher accuracy for detecting strip perforation of root canals. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline  & & & \multicolumn{3}{c}{**95\% Confidence**} & & & & \\ \cline{3-10}  & & \multirow{2}{*}{**Accuracy**} & \multirow{2}{*}{_p_} & \multicolumn{2}{c}{**Interval**} & \multirow{2}{*}{**Sensitivity**} & \multirow{2}{*}{**Specificity**} & \multirow{2}{*}{**PPV**} & \multirow{2}{*}{**NPV**} \\ \cline{5-10}  & & & & **Lower** & & **Upper** & & & \\ \cline{5-10} Observer 1 & Periapical radiograph & 0.750 & 0.003 & 0.607 & 0.893 & 0.560 & 0.920 & 0.875 & 0.677 \\ \cline{2-10}  & CBCT & 0.576 & 0.369 & 0.412 & 0.739 & 0.440 & 0.760 & 0.647 & 0.576 \\ \hline \multirow{3}{*}{Observer 2} & Periapical radiograph & 0.875 & 0.000 & 0.766 & 0.984 & 0.840 & 0.920 & 0.913 & 0.852 \\ \cline{2-10}  & CBCT & 0.773 & 0.001 & 0.635 & 0.911 & 0.826 & 0.720 & 0.731 & 0.818 \\ \hline \multirow{3}{*}{Observer 3} & Periapical radiograph & 0.896 & 0.000 & 0.795 & 0.997 & 0.958 & 0.833 & 0.852 & 0.952 \\ \cline{2-10}  & CBCT & 0.659 & 0.059 & 0.502 & 0.817 & 0.440 & 0.840 & 0.733 & 0.600 \\ \hline \multirow{3}{*}{Observers’ average & Periapical radiograph & 0.950 & 0.000 & 0.839 & 1.000 & 0.813 & 0.957 & 0.929 & 0.880 \\ \cline{2-10}  & CBCT & 0.747 & 0.031 & 0.541 & 0.954 & 0.667 & 0.900 & 0.833 & 0.783 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) values for each observer and observer’s average in detecting separated endodontic files (group 1). \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline  & & \multirow{2}{*}{**Accuracy**} & \multirow{2}{*}{_p_} & \multicolumn{2}{c}{**95\% Confidence**} & & & & \\ \cline{4-9}  & & & \multicolumn{2}{c}{**Interval**} & \multirow{2}{*}{**Sensitivity**} & \multirow{2}{*}{**Specificity**} & \multirow{2}{*}{**PPV**} & \multirow{2}{*}{**NPV**} \\ \cline{5-10}  & & & & **Lower** & & **Upper** & & & \\ \cline{5-10} Observer 1 & Periapical radiograph & 0.795 & 0.001 & 0.656 & 0.935 & 0.640 & 0.920 & 0.889 & 0.719 \\ \cline{2-10}  & CBCT & 0.920 & 0.000 & 0.832 & 1.000 & 1.000 & 0.840 & 0.862 & 1.000 \\ \hline \multirow{3}{*}{Observer 2} & Periapical radiograph & 0.932 & 0.000 & 0.845 & 1.000 & 0.957 & 0.913 & 0.917 & 0.955 \\ \cline{2-10}  & CBCT & 0.900 & 0.000 & 0.803 & 0.997 & 0.960 & 0.840 & 0.857 & 0.955 \\ \hline \multirow{3}{*}{Observer 3} & Periapical radiograph & 0.727 & 0.010 & 0.574 & 0.881 & 0.750 & 0.625 & 0.667 & 0.714 \\ \cline{2-10}  & CBCT & 0.960 & 0.000 & 0.897 & 1.000 & 1.000 & 0.920 & 0.926 & 1.000 \\ \hline \multirow{3}{*}{Observers’ average & Periapical radiograph & 0.855 & 0.000 & 0.729 & 0.980 & 0.800 & 0.909 & 0.889 & 0.833 \\ \cline{2-10}  & CBCT & 0.955 & 0.000 & 0.883 & 1.000 & 1.000 & 0.920 & 0.926 & 1.000 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Accuracy, sensitivity, specificity, PPV, and NPV values for each observer and observers’ average in detecting strip perforation (group 2). Several studies have compared the diagnostic potential of CBCT and digital periapical radiography for detecting endodontic complications. In the study performed by [PERSON] et al., the diagnostic abilities of CBCT and periapical radiography for detecting separated #10 and #35 hand files were tested. Similar to our findings, their results indicated that the sensitivity, specificity, PPV, NPV, and diagnostic accuracy of digital periapical radiography was better than CBCT in both sizes of separated instruments [21]. [PERSON] et al. simulated a series of endodontic complications in extracted teeth and compared the accuracy of CBCT and periapical radiography.