In Vitro Effects of Bleaching Agents on L929 Cell Line Efectos In Vitro de Agentes de Blanqueamiento sobre la Línea Celular L929

Bleaching agents can potentially cause damage to dental and gingival tissues. Due to the use of bleaching agents close to gingival tissues, the objective of the present study was to test the hypothesis that the higher the concentration of hydrogen peroxide, the greater is the cytotoxicity to fibroblast cells. Two concentrations of hydrogen peroxide (6%, and 7.5%) used in home bleaching techniques were evaluated regarding their possible cytotoxic effect on gingival tissues. The materials were divided into two groups as follows: Group P6 (White Class 6%, FGM), and Group P7.5 (White Class 7.5%, FGM). 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. Analysis of variance (ANOVA) with multiple comparisons and Tukey’s test were employed (P < 0.05). The results showed statistically significant differences between Groups P6 and P7,5, 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. One can conclude, therefore, that the 6 and 7,5% hydrogen peroxide demonstrated high cytotoxic character for all times studied.