## 4 Discussion
Based on their findings, periapical radiographs were more accurate for the detection of file fragments compared with CBCT, although the observed difference was not significant [22]. Their findings are consistent with our results. In another study, [PERSON] et al. used both hand and rotary separated files. Similar to our results, they indicated that periapical radiographs were superior to CBCT imaging in the detection of separated instruments [23]. Additionally, [PERSON] et al. simulated the separation of reciprocating NiTi files, rotary NiTi files, and stainless steel files. Their results showed that in the absence of filling, accuracy values were high for periapical radiographs of different digital systems and CBCT images with different voxel sizes. In filled root canals, however, the accuracy of periapical radiographs was significantly higher than that of CBCT images [24]. High-density filling material can create additional artifacts and thus may compromise the diagnosis of small fragments of separated endodontic instruments. A few other studies have used rotary instruments to simulate file separation. Consistent with our findings, [PERSON] et al. in their study concluded that digital radiography performs better for detecting separated rotary instruments [25]. Moreover, in the study of [PERSON] et al., conventional and digital periapical radiographs and CBCT performed equally for the detection of separated rotary endodontic files. In obtutated canals, the accuracy and sensitivity of CBCT were significantly lower, which can be a result of the presence of additional artifacts of the filling materials [17]. In the study of [PERSON] et al., all root perforation defects were identified with CBCT, while periapical radiographs were unable to identify the majority of perforations [22]. [PERSON] et al. performed a study to compare the diagnostic characteristics of CBCT and digital periapical radiography in three angles for detecting root perforation in obtutated and non-obtuterated root canals. Their study showed higher sensitivity, specificity, PPV, and NPV for CBCT in non-obtuterated root canals, while in obtuterated root canals all of these factors were higher for periapical radiography. Thus, the insertion of radiopaque filling materials led to a decrease in the diagnostic capabilities of CBCT imaging in their study [26]. However, in our findings, CBCT was superior to periapical radiography in filled canals. The difference between the findings can be attributed to the smaller voxel size of the CBCT unit used in our study. In addition, observers in the current study were able to view the cross-sectional images in any desired plane, which may enhance the diagnostic potential of CBCT by incorporating its unprecedented three-dimensional capabilities. [PERSON] et al. in their study concluded that the risk of misdiagnosis of strip perforation is high with both periapical radiography and CBCT imaging, However, CBCT is significantly more sensitive in the diagnosis of strip perforation [27]. It is important to select appropriate imaging techniques for diagnosing endodontic errors and complications. When complications are suspected in clinical examination and initial periapical radiography, several points need to be considered before choosing further radiographic examinations. CBCT is the imaging modality with the highest radiation dose for dental purposes, and exposes the patients to relatively higher radiation doses as compared to periapical radiography [28]. The effective dose of a CBCT scan with a small field of view is approximately 50 \(\upmu\)Sv, while two digital periapical radiographs obtained by PSP and using rectangular collimation have an effective dose of about 2.5 \(\upmu\)Sv [29]. Moreover, for endodontic purposes, CBCT scans with limited field of view and small voxel sizes are preferred to enhance the diagnostic potential [30]. Additionally, in CBCT, the presence of metallic objects in the field of view might lead to beam-hardening artifacts which may in turn affect the detection of fine details [31].