Color characteristics of various computerized machinable ceramics veneered to yttria-stabilized tetragonal zirconia polycrystalline upon different hybridized techniques.

Abstract

Background: Hybridization technique impacted color of ceramic veneered zirconia. This study examined color characteristics of different ceramics veneered zirconia upon different hybridized techniques.

Material and methods: 120 zirconia specimens (0.8 mm thickness, 12 mm diameter) were prepared from 3-yttria-stabilized tetragonal zirconia polycrystalline and unintentionally veneered with Vitabloc Mark-II (Vm), IPS e.max CAD (Em), Vita-Suprinity (Vs), and Celtra-Duo (Cd), by CAD-bonded (Cb) versus CAD-fused (Cf) hybridization (n=15/group). CIE-L*a*b* color characteristics were determined for translucency parameter (TP), contrast ratio (CR), opalescence parameter (OP), and color difference (ΔEdiff). Microstructures were investigated with SEM and XRD. Analysis of Variance and Bonferroni comparisons were determined for significant differences (p<0.05).

Results: TP and OP were significantly higher, but lower CR and ΔEdiff for Vm and Em than Cd and VS. Cf hybridized technique significantly decreased TP and OP but increased CR and ΔEdiff than Cb, which amplified color alteration. Better TP and OP, with less CR and ΔEdiff, were achieved for zirconia veneering with either Vm or Em, compared to Vs or Cd, whether hybridized with Cb or Cf technique.

Conclusions: Different veneering ceramics and hybridized techniques significantly altered color characteristics of ceramic veneered zirconia. Zirconia veneering with either Vm or Em appeared to produce better translucence and opalescence, with less contrast and color alteration than veneering with either Vs or Cd. CAD-fused decreased translucency, opalescence, and intensified color alteration due to t→m transformation. Nevertheless, the color alteration of ceramics veneered zirconia still rendered an acceptable limit, except for both Vs and Cd upon Cf hybridization. Key words:CAD/CAM, color, contrast, hybridized technique, opalescence, translucency.