The Effect of Luting Cement and Titanium Base on the Final Color of Zirconium Oxide Core Material

To evaluate the effects of different types of luting cements and different colors of zirconium cores on the final color of the restoration that simulates implant-supported fixed partial dentures (FPDs) by using a titanium base on the bottom.

One hundred and twenty zirconium oxide core plates (Zr-Zahn; 10 mm in width, 5 mm in length, 0.5 mm in height) were prepared in different shades (n = 20; noncolored, A2, A3, B1, C2, D2). The specimens were subdivided into two subgroups for the two types of luting cements (n = 10). The initial color measurements were made on zirconium oxide core plates using a spectrometer. To create the cement thicknesses, stretch strips with holes in the middle (5 mm in diameter, 70 μm in height) were used. The second measurement was done on the zirconium oxide core plates after the application of the resin cement (U-200, A2 Shade) or polycarboxylate cement (Lumicon). The final measurement was done after placing the titanium discs (5 mm in diameter, 3 mm in height) in the bottom. The data were analyzed with two-way ANOVA and Tukey's honestly significant differences (HSD) tests (α = 0.05).

The ∆E*_ab value was higher in the resin cement-applied group than in the polycarboxylate cement-applied group (p < 0.001). The highest ∆E*_ab value was recorded for the zirconium oxide core-resin cement-titanium base, and the lowest was recorded for the polycarboxylate cement-zirconium oxide core (p < 0.001).

The luting cement, the presence of titanium, and the color of zirconium are all important factors that determine the final shade of zirconia cores in implant-supported FPDs.