Effect of whitening mouth rinses on the chemical and physical properties of a nanofilled composite

Aim: This study analyzed the effect of whitening mouth rinses on water sorption (WS), solubility (SL), color change, and surface roughness of a nanofilled composite. Whitening perceptibility and acceptability (WID) were also studied. Methods: Forty specimens of Filtek Z350XT, shade EA2 were produced and randomly distributed (n=8) to AS ­ artificial saliva (control); LWE ­ Listerine Whitening Extreme; CLW ­ Colgate Luminous White; LCM ­ Listerine Cool Mint; and CP ­ Colgate Plax. They were immersed in the mouth rinses 2x/day, for one minute, during 28 days. The color was assessed using an Easyshade spectrophotometer (CIE-L*a*b* system). Surface roughness (Ra-µm) was measured with three parallel measures, using an RP-200 roughness meter. The WS and SL (µg/mm-3) were analyzed based on the ISO 4049 recommendations. The data were analyzed using one- and two-way ANOVA/Tukey tests (α=0.05). Results: Surface roughness significantly increased after immersion in AS and LCM, with no significant differences between the groups either before or after immersion. The ΔE* was not significantly different between the groups. All substances produced a ΔWID higher than the 50%:50% perceptibility and acceptability thresholds. The WS and SL were not significantly affected by the mouth rinses. Conclusion: Whitening mouth rinses did not affect WS, SL, surface roughness, and color stability of a nanofilled composite, regardless of the presence of ethanol in the composition

In vitro tooth whitening effectiveness of whitening mouth rinses

Regardless of the extensive availability of mouth rinses that claim to whiten teeth, evidence of achievement of such effect is still missing. Aim: Therefore, this study assessed in vitro the whitening effectiveness of whitening mouth rinses. Methods: Sixty intact bovine incisors were embedded in acrylic resin and had their buccal surface flattened and polished. Then, the specimens were randomly allocated to three conventional (Colgate Plax, Cepacol and Listerine Cool Mint) and three whitening mouth rinse groups (Colgate Luminous White, Cepacol Whitening and Listerine Whitening Extreme) (n=10). Following, the specimens were immersed twice a day in the mouth rinses for one minute for 28 days. In between each immersion period, the specimens remained in artificial saliva at 37oC. Color was measured at baseline, 7, 14, 21, and 28 days using a portable spectrophotometer (Easyshade, Vita Zahnfabrik, Germany) with a 6 mm of diameter probe. Color change was analyzed considering the parameters of ∆L*, ∆a*, ∆b* and, ultimately, ∆E*. The whitening efficacy of the mouth rinses was analyzed using the Whiteness Index for Dentistry (WID). Data of ∆s was analyzed using two-way ANOVA and Tukey's test (α=0.05). Results: The type of mouth rinse affected significantly all the ∆ parameters (p<0.05). A non-whitening (conventional) mouth rinse produced the highest ΔE*, followed by the three whitening mouth rinses. The application time also affected ΔE* (p<0.05), with emphasis on the third week of treatment. Only the hydrogen peroxide-containing mouth rinse (Listerine Whitening Extreme) presented a whitening effect, with an increasing trend over time. Conclusion: Although the overall color change was not different when comparing conventional and whitening mouth rinses, the hydrogen peroxide-containing whitening mouth rinse produces an increasing whitening trend over time. Not every mouth rinse that claims to whiten teeth produces the desired effect