Comparison of Color Stability Between Monolithic Zirconia Stained and Glazed with MiYO Esthetic System and Lithium Disilicate Ceramic
Author(s): Zanyar M Kareem* and Bassam K Amin
Abstract
Background/Objective: CAD/CAM-made monolithic zirconia restoration has excellent mechanical properties but limited esthetic characteristics due to low translucency. Various techniques were undertaken to enhance their translucency and esthetic. Staining zirconia by MiYO liquid ceramic system is one of these techniques. This study aimed to evaluate the color stability of the MiYO-treated monolithic zirconia and compare it with layered lithium disilicate ceramic Material and Method: Thirty ceramic specimens were prepared in the dimension of (20mm*15mm*2mm) and divided into two groups, fifteen monolithic zirconia specimens stained at two color zones with MiYO esthetic system, and fifteen lithium disilicate specimens. Both groups were subjected to thermal aging. The CIE L*a*b* color parameters were measured using the dental spectrophotometer to determine the color stability by using the color difference (ΔΕ) formula: ΔΕ= [(ΔL*) ²+(Δa*) ²+(Δb*) ²] ½. Results: The mean ± standard deviation of color difference (ΔΕ) for lithium disilicate, monolithic zirconia at zone one MiYO layer, and two MiYO layers were 1.59 ± 0.56, 2.34 ± 1.02, and 2.63 ± 1.25 after 1000 thermal cycles and 2.69 ± 0.97, 2.70 ± 1.18 and 3.51 ± 1.34 after 2000 thermal cycles respectively. After the 1000 thermocycling, a statistically significant difference of ΔΕ was found between groups (P<0.05). However, after 2000 thermal the difference in ΔΕ was considered statistically insignificant (P>0.05). No significant difference in ΔΕ was found in both zones of MiYO-stained zirconia in both stages. Conclusion: Both groups showed clinically acceptable color stability (ΔΕ<3.7) despite the perceptible color change by the human eyes (ΔΕ>1).