Evaluating the Final Color of Restorations with Three CAD/CAM Core Materials (Co–Cr, Zirconia, and PEEK), Veneered by Two Methods (Indirect CAD/CAM Composite and Heat-Pressed Ceramics)

Abstract

Background. This study aimed to evaluate the final color of restorations with three different core materials (Co–Cr, Zirconia, and PEEK) veneered with heat-pressed ceramic or CAD/CAM composite. Methods. Forty cores in the form of square with dimensions of 10 × 10 mm and thickness of 0.5 mm were milled from Zirconia and Co–Cr blocks and were veneered with either A2 shade CAD/CAM composite resin or heat-press ceramic (n = 10). Ten samples from polyetheretherketone blocks were only veneered with composite resins. A2 shade veneer material with 2 mm served as control for color evaluation of samples. Color parameters were measured by spectrophotometer. The data were analyzed using one-way ANOVA and Tukey’s post hoc test. Results. The mean color differences between Co–Cr, Zirconia and PEEK samples veneered with composite and the control sample were 2.91 (±0.45), 3.24 (±0.33), and 2.75 (±0.35) and for Co–Cr and Zirconia in ceramic groups were 6.46 (±0.32) and 1.97 (±0.19), respectively. One-way ANOVA and Tukey’s post hoc test showed a significant difference between the core groups veneered with ceramic ( $P\le 0.001$ ). The type of core material in the composite veneered samples, however, did not make a significant difference ( $P=0.186$ ). All groups except for Co–Cr-ceramic showed clinically acceptable results (ΔE < 3.7). Conclusion. Type of core material presented significant effect on the final color of restorations when ceramic was used as a veneer material. Conversely, the final color of composite veneer restorations is not affected by the core type. CAD/CAM composites can provide adequate color coverage for different core materials without exceeding a minimum clinically acceptable thickness.