
Aims and objective: Comparison of diagnostic accuracy of conventional radiography and orthopantomograph in detection of periapical lesion. Materials and Methods: The study groups comprised of 150 patients of either sex between age group of 20-60 year reported to the Department of Oral Medicine and Radiology. The determination of 'true pathology' was based on the results of the simultaneous interpretation of both the periapical and the panoramic radiographs in standard. Results: The intra-observer reliability analysis is done to measure the consistency in rating method of the observer. It was observed that with Kappa value in range of 0.6 to 0.8, the observation at two different time are significantly agreement. The detailed statistical analysis very clearly indicates that the rating given based on observation from periapical radiograph is better than the observation from panoramic radiograph. The Pearson's R coefficient, Spearman Correlation, Kappa value and Cronbach’s Alpha values for periapical radiograph are 0.714, 0.696, 0.436 and 0.833 which are significantly higher than that obtained from observation of panoramic radiograph with values 0.541, 0.604, 0.375 and 0.702 within statistical significance level. The diagnostic accuracy was evaluated with ROC analysis technique. The graph generated by the ROC curve is used to calculate the area under the curve obtained from each imaging technique. The ROC curve and area under each respective plot clearly indicate that the periapical radiography technique is better in diagnosis of lesions. Conclusion: the periapical radiographs provides more accuracy in terms of diagnosing the periapical lesion, which provides better diagnostic values as compared to the panoramic images.