Shade Matching of CAD/CAM Lithium Silicate Ceramics Veneered on Newly Introduced Foundation Material.

Statement of the problem: The emergence of Polyetheretherketone (PEEK) in prosthodontics and its use as a foundation for ceramic veenering restorations demand reassessment of shade match of final restoration.
Purpose: This study aimed to investigate the use of different foundation materials on the color output of two CAD/CAM lithium silicate ceramics.
Material and Methods: Rectangular plate specimens (60 sample) were prepared from CAD/ CAM generated all-ceramic materials of shade A2; IPS e.max (EM) CAD and Vita suprinity blocks (ZLS). A reflectance spectrophotometer used to measure the colour difference of ceramic samples before and after bonding to different foundation specimens; Zirconia (ZR), resin composite (RC), and PEEK; all of shade A2. The parameter of colour were measured via CIE L*a*b* (Commission Internationale de L’Eclairage) color system. Statistical analysis of data were done using two way ANOVA and the Tukey HSD test (α=0.05).
Results:ANOVA revealed that ΔE values influenced significantly (P<.05) by the composition of ceramic material and different foundation materials used. However; the interaction was almost not statistically significant between the variables (p=.294). In comparison to ZR and RC assemblies, the foundation material; PEEK, revealed comparable color parameters when assembled with each of the tested veneering material.
Conclusions: Zirconia reinforcement of CAD / CAM lithium silicate glass-ceramics decrease the impact of color variations on the various foundation materials used. The level of color acceptance varies between the ceramic and foundation materials tested. Compared to other widely used foundation materials (ZR and RC); PEEK displayed no different tendencies in color properties.