Color stability of recent composite resins.

The objective of the study was to evaluate the color stability of 8 recently developed resin composites when exposed to various staining agents. Six disc-shaped specimens made out of 8 resin composite materials were immersed in artificial saliva, coffee, coke, tea, orange juice and red wine. The initial color (T0) of the 288 specimens was assessed by a calibrated reflectance spectrophotometer (SpectroShade, MHT) over a black as well as a white background. All specimens were kept in an incubator (INP-500, Memmert GmbH) at 37 °C for 4 weeks. Colorant solutions were changed every 7 days to avoid bacteria or yeast contamination. After 4 weeks of storage in the colorants (T1), spectrophotometric measurements were repeated and ΔE00 was calculated. When analyzed over a white background, the mean ΔE00 values varied from 1.5 (Venus Diamond) to 52.4 (Miris 2). When analyzed over a black background, the mean ΔE00 values varied from 0.8 (Venus Diamond) to 40.0 (ELS). Significant differences were detected when comparing values at T0 and T1 (ΔE00) for both backgrounds (Anova and Fisher's LSD post hoc test). Resin composite materials do behave in a significantly different way (p value < 0.01) when exposed to various staining solutions.