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Influence of Express® and Vistascan® Image Scanning Systems on the optical density of Endodonic Cements

— This study aimed to assess whether there is influence of the Express and VistaScan scanning systems on the optical density of the image of endodontic cements. 36 specimens were used, 6 of each material, and each material was manipulated and inserted into holes in an acrylic plate supported by a glass plate. The radiographic exposure was performed on phosphorus plates together with an aluminum scale of 9 steps with 1 mm each, this being used as the gold standard. After the periapical radiographic acquisitions, the phosphor sensors were scanned by the Express and VistaScan equipment and saved in TIFF. The optical density of each material was measured in shades of gray and in millimeters of aluminum equivalent (mm Al), according to ISO 6876/2001 standards, using the ImageJ software, twice with an interval of 1 week. The optical density of the filling materials was corrected by subtracting the optical density from the glass plate. To compare the average densities according to the different cement brands, the Tukey test was applied for multiple comparisons. All tests were performed at a 5% significance level. There was a strong correlation between optical densities measured at time 1 and time 2, for optical densities measured from the Express scanning system, Pearson's correlation between measurements made at time 1 and 2 was equal to 0.9983 (p < 0.0001) and for measurements made from the VistaScan 0.9998 system (p <0.0001); in both cases the correlations are very close to 1 indicating an almost perfect correlation. In the Express system there was a variation in optical density between 155 and 185, and in the VistaScan system this density varied between 70 and 160. The VistaScan system showed a higher contrast resolution where, through the Analysis of Variance, a greater difference was observed in the densities of the evaluated cements. It was also evident that the measurement via the Express system was numerically superior to VistaScan. There was interaction between the scanning methods and filling cement, mainly in the measurements in the VistaScan system. It was observed that optical density measured in the i-Express system was numerically always higher than the optical density measured in the VistaScan system, and in the Express system, the AH Plus filling cement was the one that obtained the lowest optical density value and the MTA Fillapex reached density larger optics. In the VistaScan system, Sealer 26 cement had the lowest optical density and AH Plus cement had the highest optical density.