The purpose of this study was to investigate the effect of polishing after the in-office bleaching method in terms of tooth color and roughness of the enamel surface. Shofu Hi-Lite™ (Shofu) was used as a bleaching agent, and Pressage (Shofu), a tooth-polishing paste, was used as a polishing agent. They were applied on bovine enamel. A handysurf E-30A (Tokyo Seimitsu) was used for measurements of the roughness of the enamel surface (Ra) after each treatment. The tooth color was measured with a spectral color-difference meter for micro-surface and evaluated with the CIE L*a*b* color system. Eighteen bovine crowns were assigned to three groups. The HP group underwent polishing after the bleaching treament; the H group underwent only bleaching; the P group underwent only polishing. Among these groups, roughness in the HP group increased significantly compared with the P group. The values ΔE*ab(ΔE*ab=[(ΔL*)2+(Δa*)2+(Δb*)2]1/2), ΔL* and Δa* in the inter-group comparison increased significantly in the HP group and the H group compared with the P group. Δb* in the HP and H groups decreased significantly compared with the P group. In the intra-group comparison, ΔL* increased significantly and Δb* decreased significantly in the HP and H groups after the treatment compared with their preoperative values. No significant difference was found in Δa* in all the groups. The present study suggests that when polishing was conducted after bleaching, the surface became rougher than with only polishing or only bleaching. In the bleaching treatment group, ΔE*ab increased significantly. This was because the L* value increased and the b* value decreased significantly. No significant changes in color were found in the comparison between the group with only bleaching and the group with polishing after bleaching. The present study concluded that when the polishing was conducted after bleaching, the enamel surface became rougher, but tooth polishing after bleaching did not affect color.
