Diagnostic Accuracy of Orthopantogram in Identifying the Proximity of Inferior Alveolar Nerve Canal to the Roots of Mandibular Third Molar as Compared to Cone Beam Computed Tomography

Abstract: Background: Third molar extraction is the most frequent surgical treatment performed in a dental office. For initial risk evaluation of IAN damage, traditional radiographic examinations like orthopantomography (OPG) are indicated. To gather local evidence, we did this research. Objective: The aim of this research is to compare orthopantomography with cone beam computed tomography in identifying whether an impacted mandibular third molar (IM3M) is near the inferior alveolar nerve canal. Materials and Methods: This cross sectional (validation) study was conducted at the Department of Oral & Maxillofacial Surgery, Faisalabad Medical University, Faisalabad from 30-5-2022 to 30-11-2022 after obtaining the permission from ethical review committee (F.No.48-ERC/2020-21/PHRC/FMU/103). 280 candidates fulfilled selection criteria were selected from the OPD. Patients then underwent OPG and findings were recorded and patient was labeled as positive or negative. Later on, patients underwent CBCT and findings were recorded. All the data was recorded on proforma while analyzed in SPSS ver 20.0. Result: The mean age of patients was 34.76±9.27 years. Out of 280 patients, there were 131 (46.8%) males and 149 (53.2%) females. Out of 280 patients, 135 (48.2%) had left side IM3M extraction while 145 (51.8%) had right side IM3M extraction. On OPG, 65 (23.2%) had superimposition, 71 (25.4%) had interruption, 64 (22.9%) had darkening of roots and 80 (28.6%) had narrowing. The sensitivity of OPG was calculated as 79.8%, specificity was 97.2%, while PPV and NPV were calculated as 97.9% and 74.8% and diagnostic accuracy of OPG was 86.4%, taking CBCT as gold standard. Conclusion: Thus, OPG can be somewhat reliable method for IAN position before Im3M extraction. Keywords: Orthopantogram, Proximity of inferior alveolar nerve canal, Impacted roots, Mandibular third molar, Cone beam computed tomography, Maxillofacial trauma.