Color stability of highly filled composite resin materials for facings

Objectives: The aim of the investigation was to examine the color stability of seven resin-based facing composites with a high content of inorganic filling material (Colombus, Artglass, Sinfony, Targis, Zeta LC, Zeta HC, BelleGlass HP/dentine, BelleGlass HP/enamel). Methods: Changes in color of test samples were determined after UV irradiation in a fast-action UV instrument, Sunset CPS+, and after storage in a mouthrinse, tea, coffee, red wine and a 0.1% turmeric (curcuma) solution. Color differences were measured by using a Castor colorimeter and the total amount of color difference represented as ΔE. Results: Red wine and the turmeric solution caused the most severe cases of discoloration (ΔE>10). Tea, coffee, the mouthrinse and UV irradiation caused invisible (ΔE<1) or visible (ΔE>1), and to some extent clinically unacceptable (ΔE>3.3), discoloration. Significance: It is apparent from the results that it remains essential to improve the color stability of the composite resin materials used for facings.