Effect of whitening dentifrices on the surface hardness of tooth coloured restorative material

ABSTRACT

The present study aims to measure the surface hardness of Z-250 composite resin material and Fuji 11 LC RMGIC after brushing for 15 days and 30 days using 3 different brands of toothpaste each having two forms, regular and whitening. The study was conducted using six different groups for each material. Each group has five disc specimens obtained from [3mm x 8mm diameter] mold. Universal testing machine [Micromet 2100 series microhardness tester] was used for testing Vicker's surface hardness. All groups were stored in distilled water at room temperature. The VHN of the control groups were measured after 24 hours, 15 days and 30 days. All data were statistically analyzed with ANOVA and Tukey's Post Hoc analysis [P=0.05]. Water storage [24 hours, 15 days and 30 days] had no significant difference of surface hardness on Z-250, with Fuji II LC there was an increase in VHN between 24 hours, 15 days and 30 days groups. Signal 2 regular toothpaste showed significant increase in VHN for both Z-250 and Fuji II LC over the control group after 15 days. Although after thirty days, the toothpastes regardless whitening or regular had no effect on surface hardness of Fuji II LC, while, they all increased the surface hardness of Z-250. There was no difference in surface hardness of 250 composite resin and Fuji 11 LC RMGIC due to whitening and regular toothpastes