Changes in color and translucency of porcelain-repairing resin composites after thermocycling

Abstract

The objective of this study was to determine the changes in color and translucency of dental porcelain-repairing resin composites compared to dental porcelain after thermocycling. Color and spectral reflectance of three shades (A2, A3, and A3.5) of one brand of dental porcelain and three basic shades (A2, A3, and A3.5) and three combinations (A2/A3, A3/3.5, and A2/A3.5) of three brands of porcelain-repairing resin composites (ABT, FSP, and TCR) were measured, before and after thermocycling for 3000 cycles, relative to the illuminant D65. The specimen was 2 mm in thickness, and 1 mm of each shade was layered to make combined shades. Changes in color ( E*ab) and translucency parameter ( TP) were calculated. A general linear model by the material (porcelain or resin composite) and shade was used to compare differences ( 0.05). The range of color changes was 0.68 –1.67 in porcelain, 0.56 –1.30 in ABT, 2.28 –3.10 in FSP, and 0.36 –1.15 in TCR. The range of TP was 0.45– 0.96 in porcelain, 0.48 to 0.94 in ABT, 1.31 to 0.82 in FSP, and 0.51 to 1.91 in TCR. After thermocycling, changes in color and TP were correlated with the shade of the material, but not with the material. The discrepancy in the changes of color and translucency after thermocycling between porcelain and porcelain-repairing resin composites should be considered when selecting repairing materials.