Accuracy of the detection of simulated condylar lesions on panoramic radiography and cone-beam computed tomography

Background: Degenerative temporomandibular joint (TMJ) disease is characterized by destruction of the articular surface of mandibular condyle. Aims and Objectives: The aim of the present study was to assess the smallest lesion on mandibular condyle that could be detected on panoramic radiograph compared to conebeam computed tomography (CBCT). Materials and Methods: A total of 15 dry human mandibles were included in the study. Three surgical carbide drill bits of diameters 1.8 mm, 2.3 mm, and 4.5 mm length were used to drill holes on anterior, posterior, lateral, medial, and superior surfaces of the condyles. Panoramic and CBCT images were obtained and evaluated by two observers to detect lesions. Interobserver variability was obtained by the application of Cohen’s kappa coefficient statistical measure. Results: On panoramic images, kappa value showed fair (0.324), moderate (0.537), and substantial agreement (0.667) for small, shallow, and deeper lesion on condyle, respectively. 16.6% of small, 43.3% of shallow, and 46.3% of deeper lesions were visualized on panoramic images compared to CBCT images. These lesions were predominantly on the superior surface of the condyle. Conclusion: Panoramic radiography can be used to detect lesions on the superior surface of the condyle of more than 2.3 mm diameter or more than 4.5 mm depth. Additional imaging modality such as CBCT is recommended for TMJ degenerative disorders.