Comparison of diagnostic performance on approximal caries detection among Swedish and Chinese senior dental students using analogue and digital radiographs.

Unlabelled: The objective was to investigate diagnostic performance on approximal caries detection among Swedish and Chinese dental students using analogue and digital radiographs in vitro. Additionally, to compare the diagnostic accuracy of two image modalities for approximal caries detection. 46 extracted premolars and molars were mounted in blocks and exposed with two intra-oral systems, one CCD based digital radiographs and one with conventional films. 10 Swedish and 10 Chinese senior dental students diagnosed the approximal sites of the teeth exposed with the digital and analogue images. A 5 point diagnosis confidence scale was applied for caries registration for all the observers. Subsequently, the teeth were sectioned and histo-pathologically analyzed in order to obtain a gold standard. The data were analyzed in terms of receiver operating characteristic (ROC) curves for evaluation of diagnostic accuracy of the two radiographic methods and for the two groups of students for enamel and dentinal caries detection, respectively. The area under the ROC curve was significantly higher for dentinal caries detection compared with enamel caries detection for both Chinese and Swedish students and for both imaging modalities (p<0.001). The present results indicated that the students' ability for enamel caries detection on approximal surfaces was poor. Neither between the two student groups (p=0.15-0.64) nor between the two image modalities (p=0.34-0.91) a statistically significant difference in detecting approximal caries was found.

Conclusions: The two different intra-oral x-ray systems were equally accurate. Chinese and Swedish students showed similar outcomes in their performance for approximal caries detection.