Effect of hydrogen peroxide on color and whiteness of resin-based composites

Objective To evaluate the influence of a 35% hydrogen peroxide gel on color and whiteness changes of resin-based composites (RBC). Materials and Methods Discs (n = 10; shade A3.5 enamel; and 8 mm diameter and 2 mm thick) were fabricated from three RBC (DF- Durafill, Heraeus Kulzer; ED- IPS Empress Direct, Ivoclar Vivadent; and AP- Amelogen Plus, Ultradent Products). Three subgroups were obtained for each RBC: before bleaching (T-0) and after first (T-1) and second (T-2) bleaching applications. A dental spectrophotometer (VITA Easyshade, Vita Zahnfabrik) was used to obtain CIELAB color coordinates and whiteness index for dentistry (WID) in all periods. CIELAB (Delta Eab*) and CIEDE2000 (Delta E-00) color differences were also obtained. Perceptibility (PT) and acceptability (AT) thresholds were used to analyze values of Delta Eab*, Delta E-00, and Delta WID. Two-way analysis of variance (ANOVA; for L*, a*, b*, and WID) and one-way ANOVA and Tukey tests (for Delta Eab* and Delta E-00) were used to analyzed the results (alpha = 0.05). Results L* and WID values from all RBC did not change after bleaching applications (T-1 and T-2) (P > .05). There were no significant differences in color differences (Delta Eab* and Delta E-00) among all RBC evaluated after bleaching applications (T-1-T-0 and T-2-T-0; P > .05). Regardless of the RBC, mean values of Delta E-00 between all different periods were always below 50%:50% PT value. Conclusions The 35% hydrogen peroxide bleaching gel influences on color and whiteness of resin-based composites. However, color changes were not clinically perceived and whiteness variations were clinically acceptable. Clinical Significance Patients should be advised that existing composite restorations might not match the natural tooth color after bleaching, and their replacement may be required.