Effect of core and composite veneer color on optical properties of polyether ether ketone (PEEK) restorations

The aim of this study is to compare the translucency of different color PEEK-composite restorations and the color difference with the parameters of the VITA classical color scale. For this purpose, 10x10x12 mm3 mini-blocks were obtained from BreCAM BioHPP (Bredent, Germany) blocks by CAD/CAM method. 30 samples of 10x10x0.6 mm3 dimensions were created from the mini-blocks on a precision cutting device (Struers, USA). The samples were divided into 3 groups to represent the A1-A2-A3 groups (n=10). Color measurement before any treatment is applied to the samples; It was carried out with a spectrophotometer device (SpectroShade Micro II, Switzerland) by providing the standards recommended by CIE. Color measurements were made for each sample on black and white backgrounds, and L*,a*,b*,C and h0 values were recorded. Then, all samples were sandblasted with Al203 powders and a single layer of Visio.Link primer (Bredent, Germany) was applied, polymerized for 90 seconds. The corresponding color opaque material (Bredent, Germany) was applied to each composite group and polymerized for 180 seconds. All samples were placed in a 2,4 mm deep silicone mold, composite (Crea.lign, Bredent, Germany) was applied and polymerized for 360 seconds. The finishing process was carried out by sanding (Struers, Japan) with 800-1000-1200-2400 and 4000 grit sandpaper, respectively. Final polishing was done with sof-lex fine and extra fine polishing discs (3M ESPE, USA). Final color measurement was repeated with the same standards. With the obtained values, the color parameters of the VITA color scale, the color difference and the translucency parameters of the groups were evaluated using the CIEDE2000 color difference equation. These data were analyzed using one-way Anova followed by post-hoc pair-wise comparision (α=0.05). As a result of the study, statistically significant color difference was observed (p<0.05). The highest ∆E value was obtained in the A1(∆E00=3.7) group, and the lowest ∆E value was obtained in the A2(∆E00=2.8) group. The highest TP value was observed in the A3(∆TP00=1,23) group. A1-A2-A3 color restorations obtained from PEEK-composite materials resulted in clinically visible and unacceptable color differences. Keywords: Color Difference, Composite, Polyetheretherketone, Translucency Parameter