The Effect of Whitening Toothpastes on the Color Stability of a Smart Monochromatic Composite Resin

Abstract

Objective: The aim of this study was to evaluate the color stability of smart monochromatic composite resin after coloring with coffee solution, thermal aging and brushing with four different kinds of toothpaste.

Materials and methods: According to the manufacturer's instructions, 40 smart monochromatic composite resin (Omnichroma, Tokuyama Dental, Japan) specimens were prepared with a thickness of 2 mm and a diameter of 10 mm. The samples were divided into four groups. The first group (SFM) was brushed with Sensodyne Fresh Mint (Sensodyne GSK, UK), the second group (CW) with Colgate 2 in 1 Whitening (Colgate Palmolive, USA), the third group (OW) with Opalescence Whitening (Ultradent Products, Inc., USA), the fourth group (COW) with Colgate Optic White With Charcoal (Colgate Palmolive, USA). At time point t₀, no brushing and thermal cycles were performed. For time point t₁, simulations corresponding to 10 days of staining, thermal aging and brushing were performed. For time point t₂, simulations corresponding to one year of staining, thermal aging and brushing were performed. The color of all specimens was measured at t₀, t₁ and t₂ with a spectrophotometer. To examine the color change, ΔE₀₀ values were calculated with the CIEDE 2000 color system. Shapiro Wilk, Kolmogorov Smirnov, Wilcoxon Signed Rank, Kruskal Wallis, and Mann-Whitney U tests were used to analyze the data.

Results: According to the results of the intergroup comparison, there is no statistically significant difference between the groups in ΔE₀₀(t₀-t₁) values in terms of t₀-t₁ time period measurement (p>0.05). There is a statistically significant difference between the groups in ΔE₀₀(t₁-t₂)values in terms of t₁-t₂ time period measurement (p<0.05). The COW group had the lowest ΔE₀₀(t₁-t₂) value and the OW group had the highest ΔE₀₀(t₁-t₂) value. There is a statistically significant difference between the groups in ΔE₀₀ (t₀-t₂) values in terms of t₀-t₂ time period measurement (p<0.05). The COW group had the lowest ΔE₀₀(t₀-t₂) value and the OW group had the highest ΔE₀₀(t₀-t₂) value.

Conclusion: The whitening efficacy of different kinds of toothpaste whitening mechanisms may differ from each other. Toothpastes also show whitening on composite resins. The lowest discoloration was observed in the group brushed with toothpaste containing activated charcoal and blue covarine. The efficacy of whitening toothpastes should be supported by in vivo studies.

Keywords: colgate optic white with charcoal; composite resin; discoloration; monoshade composite resin; omnichroma; sensodyne 2 in 1 whitening; sensodyne fresh mint; whitening toothpaste.

Figure 1. Work Flow Chart