_Applied_  
_sciences_  
Comparison of Cone Beam Computed Tomography and Digital Radiography in Detecting Separated Endodontic Files and Strip Perforation  
**[PERSON] 1, [PERSON] 2, [PERSON] 3, [PERSON] 1,*, [PERSON] 4 and [PERSON] 5,*,6**  
1 Department of Oral and Maxillofacial Radiology, Dental Implants Research Center, Dental Research Institute, School of Dentistry, Isfahan University of Medical Sciences, Isfahan 81746, Iran; [EMAIL_ADDRESS]
2 Dental Students' Research Committee, School of Dentistry, Isfahan University of Medical Sciences, Isfahan 81746, Iran; [EMAIL_ADDRESS]
3 Department of Endodontics, School of Dentistry, Isfahan University of Medical Sciences, Isfahan 81746, Iran; [EMAIL_ADDRESS]
4 Dentist, Private Practice, Isfahan 81746, Iran; [EMAIL_ADDRESS]
5 Department of Neurosciences, Reproductive and Odontostomatological Sciences, University of Naples \"Federico II\", 80131 Naples, Italy
* Correspondence: [EMAIL_ADDRESS] (P.S.); [EMAIL_ADDRESS] (G.S.)  
Received: 8 November 2020; Accepted: 2 December 2020; Published: 5 December 2020  
Featured Application: Based on our findings, cone beam computed tomography was superior for diagnosing strip perforation of filled root canals, while digital periapical radiographs performed better in the detection of separated rotary files. The selection of appropriate imaging modalities for the diagnosis of endodontic complications must be performed on an individual basis according to the initial radiographic and clinical signs and symptoms.  
The separation of endodontic files and strip perforation are among procedural intraoperative complications which may ultimately lead to the failure of root canal treatment. The aim of the present study was to compare the diagnostic potential of cone beam computed tomography (CBCT) and digital periapical radiographs in detecting separated rotary files and strip perforation in filled canals. Fifty human mandibular molars were selected for this study. The teeth were randomly divided into two groups based on endodontic errors (i.e., file separation and strip perforation). In each group, 25 of 50 mesial canals were randomly chosen for simulating the errors, while the other 25 canals were considered as the control group. In group one, a simulation of the separation of rotary files was performed using ProTaper F2 files. Strip perforation of the root canals in group two was achieved by number 2 and 3 Gates Glidden drills in the coronal third of the root canals. Digital periapical radiographs in two different horizontal angles and high-resolution CBCT scans were obtained from the teeth mounted on a dry human mandible with simulated soft tissue covering. Three experienced observers who were unaware of the study groups evaluated the digital periapical and CBCT image sets in two separate readings. Intraobserver and interobserver agreements, as well as accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), were calculated and compared. Intraobserver and interobserver agreements ranged from poor to excellent and poor to good, respectively. The accuracy, sensitivity, specificity, PPV, and NPV for digital radiography in detecting separated files were 0.950, 0.813, 0.957, 0.929, and 0.880, respectively. The same values for CBCT were 0.747, 0.667, 0.900, 0.833, and 0.783, respectively. For the diagnosis of strip perforation, these values were 0.855, 0.800, 0.909, 0.889, and 0.833 for periapical radiography and 0.955, 1.000, 0.920, 0.926, and 1.000 for CBCT. In conclusion, CBCT was superior for diagnosing strip perforation of the filled root canals, while digital periapical radiographs performed better in the detection of separated rotary files.  
**Keywords:** endodontics; root canal therapy; cone beam computed tomography; dental digital radiography +
Footnote †: journal: Journal of Computational Physics