Objectives: The aim of this study was to investigate the diagnostic accuracy of conventional bitewing, periapical radiographs, unfiltered and filtered digital panoramic images for the assessment of approximal carious lesions in posterior teeth.
Methods: 20 patients who required bitewing, periapical and panoramic radiographs participated in the study. The digital panoramic images were treated with the "sharpen", "smooth" and "emboss" filters. Three experienced observers evaluated the bitewing and periapical radiographs, and the unfiltered and filtered digital panoramic images for the presence or absence of approximal carious lesions according to a 5-point confidence scale. Intra- and interobserver reliability was analysed with the Cronbach alpha test and diagnostic accuracy was evaluated using receiver operating characteristic (ROC) analysis.
Results: According to the results, the intra- and interobserver agreement levels were found to be almost perfect. The highest diagnostic accuracy was found for the bitewing, followed by the periapical and panoramic images. Compared with the unfiltered panoramic images, the filtered images had an almost equal or slightly higher diagnostic accuracy. The largest increase in diagnostic accuracy was observed for those images filtered with the emboss filter.
Conclusions: The accuracy of unfiltered and filtered digital panoramic images is lower than conventional bitewing and periapical radiographs. The filtration of the digital panoramic images, especially the emboss filter, may have some value for the detection of approximal carious lesions.