Aims: to evaluate the agreement of approximal caries diagnosis obtained with different types of digital radiography systems after image import into a reference sytem. Methods; digital radiographs were taken from 30 extracted human premolars with 60 diagnostic surfaces using a reference and two test systems from which images were imported as TIFF files. Four observers evaluated the radiographs using the reference software. Teeth were sectioned for histology. Agreement between histology and each technique was calculated using ROC statistics. Results: the areas under the ROC curves were not significantly different between reference and test systems. Conclusions: importing files from different programs did not affect diagnostic accuracy.