Comparison of conventional and digital radiography systems with regard to radiopacity of root canal filling materials

Abstract Akcay I, Ilhan B, Dundar N. Comparison of conventional anddigital radiography systems with regard to radiopacity of rootcanal filling materials. International Endodontic Journal. Aim To compare the radiopacity of five root fillingmaterials as measured on digitized E-speed films,storage phosphor plate and CCD sensor images.Methodology Radiopacity of Resilon cones andEpiphany, MM-Seal, EndoREZ and AH Plus sealerswere investigated. Ten acrylic plates were prepared andfilled with the materials. Samples were radiographedtogether with samples of dentine and an aluminiumstepwedge. Images were obtained using E-speed films,Digora storage phosphor plates and Schick CDR CCDsensor. Conventional radiographs were digitized usinga desktop scanner. Mean grey values of the materials,stepwedge and dentine were measured using thehistogram analysis function of Photoshop 7.0. A graphof radiographic density versus thickness of the alumin-ium was drawn for each image from which theradiographic densities of the materials were determinedin relation to the aluminium thickness. The mean wascalculated, and the data were analysed using repeatedmeasures anova and Bonferroni tests (P < 0.05).Results There were significant differences betweendifferent imaging modalities (P = 0.018) and rootfilling materials (P < 0.001). A statistically significantinteraction between imaging modality and materialwas also observed (P < 0.001). All materials hadradiopacity above 3 mm of aluminium regardless ofthe imaging technique. The radiopacity of Resilon andEpiphany was significantly higher on digital imagescompared with digitized E-speed film images(P < 0.001).Conclusion The choice of imaging system may effectradiopacity measurements. It is possible that radiopac-ity as recorded on traditional or digitized films is notindicative of the radiopacity as recorded on a digitalsensor.Key words: digital radiography, endodontics, radio-pacity, root filling materials.