The effect of current bleaching agents on the color of light-polymerized composites in vitro

Abstract 

Statement of problem

Bleaching agents may affect the color of existing composite restorations.

Purpose

The purpose of this study was to compare the effect of 10% carbamide peroxide and 10% hydrogen peroxide on the color of light-polymerized hybrid, macrofilled, and polyacid-modified composites.

Material and methods

Two light-polymerized hybrid composites (3M Valux and Spectrum TPH), 1 macrofilled condensable composite (Solitaire), and 2 polyacid-modified composites (Dyract AP and Compoglass) were used. The hybrid composites served as controls. The color of 8 specimens of each material was analyzed by use of a spectrophotometer before bleaching. The specimens were then divided randomly into 2 subgroups (n=4). One group was immersed in 10% carbamide peroxide solution and the other in 10% hydrogen peroxide, for 8 hours each for 14 consecutive days. After bleaching, color changes (Δ E) were determined for each material and compared by use of the Kruskal-Wallis test, followed by the Mann-Whitney U test (P<.05).

Results

After bleaching with carbamide peroxide, the color changes (ΔE) for Dyract AP (2.18; SD = 1.41), Compoglass (1.14; SD = 0.26) and Solitaire (1.56; SD = 0.89) were higher than the color changes recorded for 3M Valux (0.63; SD = 3.60), and Spectrum TPH (0.66; SD = 1.24). The differences between materials bleached with carbamide peroxide were not statistically significant. After bleaching with hydrogen peroxide, the color changes for Dyract AP (9.39; SD = 0.53) and Compoglass (5.15; SD = 0.52) were higher than the changes recorded for Spectrum TPH (4.53; SD = 1.53) and 3M Valux (3.41; SD = 4.40), whereas the color change of Solitaire (3.69; SD = 0.57) was significantly higher than that of 3M Valux (P=.01). The color changes for all restorative materials tested were clinically detectable after the application of 10% hydrogen peroxide. However, clinically noticeable discoloration was observed only for Dyract AP treated with 10% carbamide peroxide.

Conclusion

In comparison to 10% carbamide peroxide, 10% hydrogen peroxide caused more color changes in the composites tested.