Influence of background color on the color changes of resin composites after accelerated aging

Purpose: To evaluate the changes in color and color coordinates after accelerated aging of resin composites depending on the background color. Methods: Color of seven resin composites (14 shades, 1 mm-thick) was measured in the reflectance mode over a zero calibration box, a white background, and a black background. After baseline color measurement, specimens were aged for total energy of 150 kJ/m(2). Color change after aging was calculated over three backgrounds. Based on the data of A2 shade composites, the influence of the background color on the changes in color (Delta E*ab) and changes in three color coordinates (Delta L*, Delta a* and Delta b*) after aging was analyzed by ANOVA (P< 0.01). Correlation among the color changes over three backgrounds was determined with a linear regression analysis. Results: Background color influenced Delta E*ab, Delta L*, Delta a* and Delta b* values. There were significant correlations among the color changes over three backgrounds in the reflectance mode (r = 0.95-0.98).