Measurement of the optical density of packable composites: comparison between direct and indirect digital systems.

The aim of this study was to measure the optical density of four packable composite resins with widths of 1, 2, 3 and 4 mm, by means of Digora (direct) and DentScan DentView (indirect) digital imaging systems, in order to compare both methods. Twenty acrylic plates, with the proposed thicknesses, were used, each one containing a sample of each resin. Each acrylic plate was radiographed three times, under a standardized technique. For the Digora system, an optical plate was used under each resin sample, and, for the DentScan DentView system, occlusal films were employed, totalizing 60 exposures for each system. Optical plates and films were scanned and three consecutive optical readouts were carried out, totalizing 1,440 readouts. The results were submitted to statistical analysis and revealed that the average optical density of the four resins always increased as thickness increased. Regarding the comparisons between the composite resins, in both analysis the resin with the greater optical density was Surefil followed by Prodigy Condensable, Alert and Solitaire . The correlations between the results of Digora and DentScan DentView were significant for the different thicknesses and materials. The observed tendency is that as the values obtained with the Digora system increase, so do the values obtained with DentScan DentView . While thickness increased, the values of optical density in both Digora and DentScan DentView tended to approach each other. The Digora system presented smaller amplitude between the results obtained in adjacent thicknesses.