Methods: Fifty bovine teeth were stained with the black tea and bleached by an in-office beaching material (TiON In Office, GC, Japan). The teeth were divided in five groups, with 10 teeth in each group (n=10). They were applied with 0.2%, 2% NaF solution, CPP-ACP paste (MI Paste, GC, Japan), CPP-ACP paste containing fluoride (MI Paste Plus, GC, Japan) for 1 hour, or without application served as control group. Then, each tooth was immersed into the black tea again. CIE L*a*b* of the stained surface of each tooth was measured by a dental color meter (Shade Eye NCC, Shofu, Japan) after bleaching, at 1/3/ 6 hours and 1/2/3/7 days after immersion, and the changes in color were evaluated. Other specimens were prepared and the bleached and stained surfaces were observed by a scanning electron microscope (SEM) at each period.
Results: Color change was increased gradually by immersion in the black tea in all groups. The color changes of all experimental groups were less than that of control group. Significant difference was not found in the SEM images among all groups at each period.
Conclusions: It was suggested that application of NaF and CPP-ACP was expected to be able to prevent from re-staining after office-bleaching.
Keywords: Bleach, Color, Enamel, Esthetics and Stain
See more of: Dental Materials 11: Color and Appearance (Esthetics)