Silorane, ormocer, methacrylate and compomer long-term staining susceptibility using ΔE and ΔE₀₀ colour-difference formulas

The aim of this study was to evaluate the staining susceptibility of a silorane (Filtek Silorane), an ormocer (Ceram X Duo), a methacrylate (Tetric EvoCeram) and a compomer (Dyract) exposed on the long term to various staining agents by using ΔE and ΔE₀₀ colour-difference formulas. Thirty-six disc-shaped specimens were made of each of the four chemically different materials, randomly divided in six groups (n = 6) and immersed in five staining solutions (red wine, juice, coke, tea and coffee) or stored dry (control) in an incubator at 37 °C for 99 days. Spectrophotometric measurements by means of a spectrophotometer (Spectroshade Handy Dental, MHT) were repeated over a white (L* = 92.6, a* = −1.2, b* = 2.9) and black (L* = 1.6, a* = 1.2, b* = −1.0) background made of plasticized paper, in order to determine the colour changes according to ΔE, ΔE₀₀ and translucency formulas. Statistical analysis was performed by means of factorial Anova, Fisher’s LSD test (post hoc) and a Spearman rank correlation between ΔE and ΔE₀₀. When analysed over a white background, mean ΔE₀₀ values were highly significantly different and varied from 0.8 (Ceram X Duo/air) to 20.9 (Ceram X Duo/red wine). When analysed over a black background, mean ΔE₀₀ values were highly significantly different and varied from 1.0 (Ceram X Duo and Tetric/air) to 25.2 (Ceram X Duo/red wine). Differences in translucency varied from 0.3 (Ceram X Duo/air) to 21.1 (Ceram X Duo/juice). The correlation between ΔE and ΔE₀₀ over a white background was 0.9928, while over a black background, it was 0.9886.