Evaluating the Effect of Active Charcoal-Containing Toothpaste on Color Change, Microhardness, and Surface Roughness of Tooth Enamel and Resin Composite Restorative Materials

Abstract

Methods

Thirty-six bovine incisors and resin composite samples were prepared, stained with black tea, and then randomly divided into two groups. The samples were brushed with a charcoal-containing toothpaste (Colgate® MAX WHITE) and daily toothpaste (Colgate® Max Fresh) for 10,000 cycles. Before and after brushing cycles, color variables ( ΔL, Δa, Δb), total color change ( ΔE), plus Vickers microhardness were evaluated. Two samples of each group were prepared for surface roughness assessment via atomic force microscope. Data were analyzed by Shapiro–Wilk, Independent sample t-test and Mann–Whitney U tests.

Results

According to the obtained results, ΔE and ΔL were significantly higher whereas Δa and Δb were noticeably lower in charcoal-containing toothpaste group in comparison with daily toothpaste in both composite and enamel samples. The microhardness of samples brushed with Colgate® MAX WHITE was significantly higher than that of Colgate® Max Fresh in enamel ( P = 0.04), whereas no significant difference was found in composite resin samples ( P = 0.23). Colgate® MAX WHITE enhanced the roughness of both enamel and composite surfaces.

Conclusion

The charcoal-containing toothpaste could improve the color of both enamel and resin composite with no negative effect on microhardness. Nevertheless, its adverse roughening effect should be considered occasionally on composite restorations.