Purpose—To examine the effect of staining solutions on the discoloration of resin
nanocomposites.
Methods—Three resin nanocomposites (Ceram X, Grandio, and Filtek Z350) were light cured
for 40 seconds at a light intensity of 1000 mW/cm2. The color of the specimens was measured in
%R (reflectance) mode before and after immersing the specimens in four different test solutions
[distilled water (DW), coffee (CF), 50% ethanol (50ET) and brewed green tea (GT)] for 7 hours/
day over a 3-week period. The color difference (ΔE*) was obtained based on the CIEL*a*b* color
coordinate values.
Results—The specimens immersed in DW, 50ET and GT showed a slight increase in L* value.
However, the samples immersed in CF showed a decrease in the L* value and an increase in the
b* value. CF induced a significant color change (ΔE*: 3.1~5.6) in most specimens but the other
solutions induced only a slight color change. Overall, coffee caused unacceptable color changes to
the resin nanocomposites
