Color differences and color changes in Vita Shade tooth-colored restorative materials

Purpose: To evaluate the color differences of four tooth-colored restorative materials of the same designated Vita shade, and the color changes of the materials caused by light curing. Methods: CIELAB coordinates (L* a* b*) of four tooth-colored materials: Clearfil ST (CL), Beautifil (BE), Reactmer (RE) and Z250 (Z2) were determined in three shades (A2, A3 and B3) before and after light curing using a colorimeter. From the L* a* b* after light curing, CIELAB color differences (DeltaE*) between different cured materials of the same shade name were calculated. If the calculated DeltaE* were above 2, color differences were estimated as "perceptible". DeltaE* was also calculated before and after light curing, using the CIELAB values, in order to evaluate color changes caused by light curing. Results: As for the DeltaE* between various cured materials of the same shade, except for DeltaE* between BE and RE on A2 and between BE and RE on A3, every combination indicated perceptible color differences. The DeltaE* calculated before and after light curing of A2, A3 and B3 shades were 7.4, 7.1 and 7.2 for CL, 6.0, 5.1 and 4.8 for BE, 4.0, 3.2 and 3.4 for RE and 1.8, 1.7 and 2.1 for Z2, respectively, indicating that most materials showed perceptible color changes.