Effect of Resin Cement Brand on the Color of Zirconia-Based Restorations

Abstract

Purpose: The purpose of this in vitro study was to evaluate the effect of resin cement brand on the color of zirconia-based restorations.

Materials and methods: Ninety A2 shade veneered zirconia disc specimens (0.5 mm zirconia thickness, 1 mm veneer thickness, 10 mm diameter) and 90 A3.5 shade composite resin background specimens (10 mm height, 10 mm diameter) with a superficial cement space (0.1 mm depth, 8 mm diameter) were fabricated. The zirconia specimens were cemented to the background specimens using universal resin cements: RelyX Unicem 2 (RU), PANAVIA SA Cement Plus (PS), and NX3 Nexus (NN). CIELab values were measured with a spectrophotometer before and after cementation. ∆E values were calculated to determine the color differences between before and after cementation of specimens (∆E₁ ), and between the A2 VITA classical shade tab and specimens before cementation (∆E₂ ) and after cementation (∆E₃ ). The ΔE values were compared with an acceptability threshold (ΔE = 3.7) to evaluate color changes/matches. Welch, 1-way ANOVA, Games-Howell, Tukey HSD, and 1-sample t test were used to analyze data (p < 0.05).

Results: Mean ΔE₁ values were 0.6 ± 0.3 for RU, 0.8 ± 0.4 for PS, and 0.6 ± 0.2 for NN. Resin cement brand significantly affected the ΔE₁ (p = 0.029) and the ΔE₃ (p < 0.001). Mean ΔE₃ values were 3.6 ± 0.3 for RU, 3.5 ± 0.3 for PS, and 3.9 ± 0.3 for NN. RU (p = 0.960) and PS (p = 0.999) showed a color match, but NN did not (p < 0.001).

Conclusions: The resin cement brand affected the color match of zirconia-based restorations. Although the tested cements created minor color changes, RU and PS were better than NN for color match. The use of resin cements with the corresponding shade to the target shade is indicated.

Keywords: Esthetics; Y-TZP ceramic; luting agent; shade; spectrophotometry.