COMPARISON OF MASKING ABILITY OF TWO CERAMICS IN TWO DIFFERENT THICKNESSES UNDER VARIOUS BACKGROUNDS

Abstract

Purpose: The objective of this study was to compare and evaluate the influence of material type and thickness on masking ability under various backgrounds. Materials and Methods: A total of 36 disc-shaped specimens (15 mm diameter × 0.5 and 1.0 mm thicknesses) were fabricated from lithium disilicate glass ceramic (IPS e.max Press, n=6), high-translucency zirconia (Lava Plus, n=6), and high-translucency zirconia with framework modifier material (Lava Plus + Lava Ceram, n=6). Contrast ratio was measured over white and black background. Color difference was measured over various backgrounds: white, black, metal, resin composite shade A2, A3, and C4. White background was used as a control group. Contrast ratio and color difference values were analyzed with two and three-way ANOVA followed by Bonferroni post hoc test (P<.05). Results: Contrast ratio of IPS e.max Press at 0.5 mm and 1.0 mm showed highest value (0.73 ± 4.37 and 0.87 ± 0.58) when compared to Lava Plus + Lava Ceram and Lava Plus groups. IPS e.max Press at both thickness showed highest masking ability over various backgrounds were as follows: Black (ΔE = 11.64 ± 0.84, 5.61 ± 0.29), Metal (ΔE = 10.31 ± 0.60, 5.08 ± 0.27), A2 (ΔE = 8.54 ± 0.46, 4.23 ± 0.28), A3 (ΔE = 8.26 ± 0.40, 4.22 ± 0.29), and C4 (ΔE = 9.12 ± 0.46, 4.64 ± 0.29). Higher contrast ratio and masking ability significantly related to thicker material. Material type significantly related to masking ability. Conclusion: Ceramic type and thickness had significant effect on contrast ratio and masking ability. Contrast ratio and masking ability increase as thickness increase. Masking ability was highest with IPS e.max Press, intermediate with Lava Plus + Lava Ceram, and lowest with Lava Plus group.