Effect of bleaching on the inside of tooth substrate

Abstract

Purpose: The purpose of this study was to evaluate the extension of bleaching effect by linearly measurement on the crosscut surfaces of bleached teeth in vitro.Methods: Thirty extracted bovine incisors were stained by black tea and were divided three groups in each of ten. The labial surface was bleached using an in-office bleaching material for 0, 3, and 6 times respectively. Then, teeth were crosscut and color was measured in bleached and not bleached area linearly from enamel surface to pulpal dentin to obtained CIE L*a*b* values using a digital camera with CIE XYZ color gamut (RC500). And whiteness index (WID) was calculated from those values.Results: Both 3-times and 6-times bleaching showed the bleaching effect and 6-times bleaching extended the effect deeper than 3-times bleaching. Three samples of 3-times bleaching group and one sample of 6-time bleaching group showed less bleaching effect at enamel dentin junction (EDJ). In 3-times and 6-times bleaching groups, WID of enamel was statistically higher than those of shallower and deeper dentin.Conclusion: It was concluded that bleaching effect was extended deeper along with dentinal tubules beyond EDJ.