Separate contribution of dentin and enamel to color changes caused by staining pigments and dental bleaching

Aim: This study assessed the changes in color and translucency of dentin and enamel after staining and bleaching procedures as well as the contribution of the tissues to color change (CTCC). Materials and methods: Fifty enamel–dentin specimens were obtained from bovine incisors and grouped into 10 blocks based on the similarity of the baseline color. One specimen in each block was used as the control, and the others were intrinsically (blood) or extrinsically (coffee) stained. One stained specimen for each pigment was bleached with 35% hydrogen peroxide. The enamel was separated from the dentin, and the tooth color and translucency parameter (TP) were measured individually and after recombining these substrates. Changes in color (ΔE00), whitening index (WI), and TP caused by the staining and bleaching procedures were estimated through assessing the color differences compared with the controls. CTCC was also calculated by recombining the enamel and dentin tissues from different treatments. The data were analyzed using the paired t test or the two-way repeated measures ANOVA (α = 0.05). Results: Extrinsic staining procedures produced higher color changes than intrinsic ones, except in dentin. The highest bleaching effect was observed in the dentin of specimens that were extrinsically stained. Similar CTCC values were observed for the dentin and enamel for both the staining and bleaching procedures. Except for the specimens that were treated with intrinsic staining and became more translucent after the bleaching procedure, the other treatments resulted in non-significant TP changes. Conclusions: Staining the specimens extrinsically resulted in higher color change than staining them intrinsically, and these specimens were more affected by the bleaching procedure. Enamel and dentin demonstrated similar CTCC values.