Effect of Implant Abutment Material and Luting Cement Shade on the Color of High Translucency Zirconia

Purpose: The purpose of this in vitro study was to assess the influence of implant abutment material – titanium, gold-hue titanium and zirconia – as well as cement shade – transparent and opaque – on the color of high translucency zirconia implant restorations. Materials and Methods: Eighty discs (10x0.8mm, shade A2) were fabricated from IPS e.max ZirCAD MT to model a high translucency zirconia ceramic. Twenty discs (10x0.8mm) were fabricated from titanium, anodized (gold-hue) titanium, and zirconia (IPS e.max ZirCAD MO, shade A1) to model implant abutment materials. Twenty discs (10x0.8mm) were fabricated from Telio CAD (shade A2) as a control. The high translucency zirconia ceramic discs were cemented to the different abutment material and control discs with two different shades of resin cement – transparent and opaque. A spectrophotometer was used to record CIELab color coordinates for each sample in order to calculate the color difference (ΔE00) between experimental and control groups. One-way ANOVA with Bonferroni post hoc tests was used to analyze the effect of different implant abutment materials and an independent samples student t-test was used to analyze the effect of the cement shades. Results: Abutment material, cement shade and their interaction were significant for ΔE00 values (P<.001). Clinically unacceptable results (ΔE00 > 2.25) were observed for titanium and gold-hue titanium abutments, regardless of the cement shade used (8.69-12.85). Clinically acceptable results (ΔE00 < 2.25) were found for zirconia abutments with both cement shades. The opaque shade cement significantly improved the color difference value for all abutment materials relative to the transparent shade cement (p<.05); however, only the zirconia abutments led to clinically acceptable results. Conclusion: The color result of a high translucency zirconia implant restoration fabricated over a titanium or gold-hue titanium abutment may be clinically unacceptable. Zirconia abutments may be more suitable for high translucency zirconia ceramics, especially when used with an opaque shade cement.