Comparative Accuracy of Panoramic Radiograph and Cone-beam Computed Tomography Images in Identification and Measurement of the Anterior Loop of Mental Nerve: A Meta-analysis and Review of the Literature

Aim and objective: This study aimed to assess the relative accuracy of two-dimensional panoramic radiographs compared with three-dimensional computed tomography (CBCT) images for identification and measurement of the anterior loop of the mental nerve. Materials and methods: The study was about to determine the comparative diagnostic accuracy of panoramic radiograph and cone-beam computed tomography and the study protocol was set according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) diagnostic test accuracy guideline. The search was limited to English literature only and included an electronic search through PubMed and Google Scholar databases. The search was further complemented by extensive hand-searching. All studies published up to November 2019 were included (without any starting limit). Two independent investigators extracted the data and assessed the studies based on the inclusion and exclusion criteria. Results: Out of the initial 308 records, only 4 studies were included in this review for qualitative data synthesis. The quality assessment of included studies was done through QUADAS-2. Quantitative data synthesis was done to compare the relative accuracy of two-dimensional radiographs compared with three-dimensional scans from three out of the four selected articles. Statistical analysis was done with the help of Meta-DiSc version 1.4. The pooled sensitivity of panoramic radiography was 0.45 (CI 95%: 0.34–0.56) and pooled specificity was 0.75 (CI 95%: 0.69–0.80). In the symmetric summary receiver operating characteristic (SROC) plot, the area under the curve (AUC) was 0.8832, and Q * was 0.8137. Conclusion: Compared with cone-beam computed tomography (CBCT) images as the gold standard reference test, two-dimensional panoramic radiographs showed lower sensitivity and reasonable specificity. It is clear from the SROC curve that panoramic radiography can be used for the identification of the anterior loops. Still, it is better to avoid it as an alternative to three-dimensional scans to determine the presence and extension of the anterior loop of the mental nerve because of the tendency toward low sensitivity and over or under-estimation of the length.