Objectives . The aim of the study was to assess the correlation between the percentage of fillers and the colorimetric parameters of colored resin matrices used for dental composites.
Materials and methods . Six colored resin matrices (Herculite B1 Enamel, A3 Enamel, C4 Enamel, B1 Dentin, A3 Dentin, and C4 Dentin, provided by Kerr-Hawe company by incorporating the normal coloring pigments for the given shade into the neat resin) were mechanically mixed with various concentrations of a barium glass filler (0.7 μm mean particle size, provided by Kerr-Hawe company) in a DAC-150 mixer (Flacktek, Landrum, SC, USA). The experimental composites contained filler levels of 30, 35, 40, 45, 50, 55, 60, 65 and 70 wt%. Five one mm thick, disk-shaped samples were prepared for each experimental group by curing in a standard mold with a QTH light (Trilight Elipar- 3M/Espe) at 800 mW/cm 2 . Samples were stored for one week after the light curing at 37 °C in air before the colorimetric evaluation. One reading per sample was performed either on a white background or on a black background with a color guide (Byk Gardner): illuminant C, illuminating/viewing geometry 45°/0° and standard observer 2 degrees. 12 colorimetric parameters were measured: L*, a*, b*, C* (chroma), h° (hue), White Berger (WB) Index, Yellowness (YI) D1925 index. Linear correlations were calculated and R 2 data are given in the following table (data obtained either on a white-W- or on a black-B- background).
Shades | Colorimetric parameters | |||||||
---|---|---|---|---|---|---|---|---|
L* | a* | b* | C* | h° | WB | YI D1925 | ||
B1 E | W | 0.518 | 0.503 | 0.957 | 0.955 | 0.870 | 0.958 | 0.967 |
B | 0.920 | 0.149 | 0.927 | 0.927 | 0.710 | 0.671 | 0.960 | |
A3 E | W | 0.059 | 0.943 | 0.991 | 0.991 | 0.920 | 0.988 | 0.988 |
B | 0.983 | 0.079 | 0.820 | 0.584 | 0.748 | 0.850 | 0.718 | |
C4 E | W | 0.742 | 0.928 | 0.938 | 0.938 | 0.906 | 0.936 | 0.957 |
B | 0.974 | 0.310 | 0.060 | 0.050 | 0.235 | 0.780 | 0.637 | |
B1 D | W | 0.296 | 0.335 | 0.974 | 0.969 | 0.946 | 0.966 | 0.974 |
B | 0.780 | 0.610 | 0.967 | 0.956 | 0.959 | 0.912 | 0.970 | |
A3 D | W | 0.823 | 0.959 | 0.973 | 0.974 | 0.940 | 0.967 | 0.974 |
B | 0.659 | 0.700 | 0.961 | 0.964 | 0.854 | 0.958 | 0.969 | |
C4 D | W | 0.916 | 0.958 | 0.979 | 0.981 | 0.926 | 0.947 | 0.970 |
B | 0.929 | 0.825 | 0.665 | 0.652 | 0.820 | 0.878 | 0.917 |