PURPOSE: To test the hypothesis that the higher the concentration of carbamide peroxide, the greater is its cytotoxicity to fibroblast cells. METHODS: Three concentrations of carbamide peroxide (10%, 16%, and 22%) used in home bleaching techniques were evaluated regarding their cytotoxic effect on gingival tissues. The materials were divided into three groups as follows: Group C10 (White Gold Home 10%, Dentsply), Group C16 (White Gold Home 16%, Dentsply, and Group C22 (Nite White 22%, ACP Discus Dental). The cytotoxicity essay was carried out using cell cultures (mouse fibroblast L929 cell line) in which the viable cells were determined by means of the dye-uptake method performed at 2, 4, and 8 hours. Data were analyzed by analysis of variance (ANOVA) with multiple comparisons and Tukey's test (P<0.05). RESULTS: The results showed statistically significant differences between Groups C10, C16, C22, and the cell control at 2, 4, and 8 hours (P<0.05). The amount of cell lysis increased proportionally to the exposure time to the materials studied. CONCLUSION: The 22% carbamide peroxide group was more toxic than the other two groups (16% and 10% concentration) regardless of the exposure time.
Toxicity; hydrogen peroxide; dental bleaching
