EFFECT OF VARIOUS BLEACHING METHODS ON COLOR CHANGE AND SURFACE ROUGHNESS OF HUMAN ENAMEL

Abstract

Purpose: This study investigated the effect of different bleaching methods on color change and surface roughness of human enamel. Materials M GP1: 3D Crest White Strips, GP2: Phillips Zoom Whitening Pen, GP3: Rembrandt Deeply White + Peroxide Mouthwash, GP4: Opalescence PF 15% CP, GP5: Opalescence Boost 40% HP (as control group). Bleaching was performed according to manufacturers’ instructions. Color change and enamel surface roughness measurements were performed by spectrophotometer and Atomic Force Microscope respectively at pre and post-bleaching intervals. Data were collected and statistically analyzed using ANOVA followed by Tukey’s HSD Post Hoc test (p≤0.05). Results: For color changes; mean ΔL* values were: 3.92(0.23), 2.44(0.15), 2.5(0.2), 2.6(0.17) and 4.1(0.25) for GP1, GP2, GP3, GP4, and GP5 respectively, Δa* means were: 0.6(0.04), 0.1(0.01), 0.15(0.01), 0.2(0.03) and 0.79(0.05) for GP1, GP2, GP3, GP4, and GP5 respectively, while means for Δb* were: 1.18(0.03), 0.33(0.01), 0.52(0.02), 0.54(0.01) and 1.27(0.07) for GP1, GP2, GP3, GP4, and GP5 respectively. The color change values (ΔE) were: 4.13, 2.46, 2.55, 2.66 and 4.36 for GP1, GP2, GP3, GP4, and GP5 respectively. A statistical significant difference (p≤0.05) is present between Gp1 versus Gp2, Gp3 and Gp4, also between Gp5 versus Gp2, Gp3 and Gp4. No statistical significant difference (p≤0.05) between Gp1 & Gp5 and also between Gp2, Gp3 and Gp4. For surface roughness; mean (Ra) values for pre-bleaching tested groups were: 106.3(8.5), 109.1(10.2), 108(12.2), 110(11.9) and 107(9.7) for GP1, GP2, GP3, GP4, and GP5 respectively. While, post-bleaching values were: 90.3(6.3), 92.3(5.6), 93.6(5.4), 94.7(6.1) and 93.1(3.6) for GP1, GP2, GP3, GP4, and GP5 respectively. However, none of the tested methods showed statistically significant changes in surface roughness (p≤0.05). Conclusions: In-office bleaching may still achieve best whitening effect compared to whitening pen, whitening mouthwash, and home bleaching, while Whitestrips could have a comparable effect. All tested bleaching methods had no effect on enamel surface roughness