Evaluation of chromatic changes of a nanocomposite resin using the new whitness index.

BACKGROUND AND AIMS: To evaluate the staining effects of two brands of coffee and the bleaching efficiency of two in-office bleaching methods, upon different opacities of a commercial nanocomposite. METHODS: Twenty four specimens of each opacity, A3 Dentin, A3 Body and A3 Enamel, were fabricated from Filtek Supreme (3MEspe). The specimens were further divided into two groups (n=12) and were immersed in two coffee solutions (Bio Organic Coffee Bellarom, 100% Arabica, and Iulius Meinl Coffee), for 24 hours. Between the staining sessions, the specimens were stored in sterile water, at 37°C. Each group was further divided into three (n=4), in order to be bleached, as follows: Group 1 - Beyond 35% in office, for 4 applications of 15 minutes each, Group 2 - Zoom Day White 6% in office, for 4 applications of 15 minutes each, Group 3 - Control Group, stored in sterile water. Color values were measured with a dental spectrophotometer Vita EasyShade 4.0 and five measurements were recorded for each sample at a time. Lightness L*, color coordinates a* and b* were recorded, at baseline, after staining in coffee and after bleaching. Whiteness index (WID) of the three composite resins (A3D, A3B, A3E) in the three moments were calculated, as well as the color difference Delta E* correspondent to the staining and bleaching process. Data were analyzed using one-way repeated measures ANOVA and the WID index was calculated WID (p<0.05). Univariate analysis of variance was performed for assessing the influence of staining solution upon composite resins, as well as for testing the effect of bleaching agents. The significance level was set at α=0.05 and pairwise comparisons were adjusted by the Least Significant Difference method. RESULTS: The pairwise comparisons showed no significant difference between the effects of the two bleaching agents upon the WID, meaning that they induce almost similar color changes. The results of the univariate ANOVA test indicated a significant effect of the composite resin and the staining solution upon the WID (p<0.05). However, no significant interaction effect was found between the composite resin and the staining solution (p=0.095). There was a significant difference in the staining effect of the two coffee solutions only for A3B and A3E composite resins (p<0.05). CONCLUSIONS: The chromatic changes of the nanocomposite resin could be evaluated by the variation of the whiteness index. The staining effect induced by the two types of coffee was similar. The most effective protocol was the in-office bleaching method based on Beyond 35%.

Melanoma Inhibition by Anthocyanins Is Associated with the Reduction of Oxidative Stress Biomarkers and Changes in Mitochondrial Membrane Potential.

Anthocyanins are water soluble pigments which have been proved to exhibit health benefits. Several studies have investigated their effects on several types of cancer, but little attention has been given to melanoma. The phytochemical content of nine different berry samples was assessed by liquid chromatography followed by electrospray ionization mass spectrometry (LC-ESI+-MS). Twenty-six anthocyanins were identified, after a previous C18 Sep-pak clean-up procedure. Chokeberry and red grape anthocyanins rich extracts (C-ARE and RG-ARE) were selected to be tested on normal and melanoma cell lines, due to their different chemical pattern. C-ARE composition consists of cyanidin aglycone glycosylated with different sugars; while RG-ARE contains glucosylated derivatives of five different aglycones. Both C-ARE and RG-ARE anthocyanins reduced proliferation, increased oxidative stress biomarkers and diminished mitochondrial membrane potential in melanoma cells, having no negative influence on normal cells. A synergistic response may be attributed to the five different aglycones present in RG-ARE, which proved to exert greater effects on melanoma cells than the mixture of cyanidin derivatives with different sugars (C-ARE). In conclusion, C-ARE and RG-ARE anthocyanins may inhibit melanoma cell proliferation and increase the level of oxidative stress, with opposite effect on normal cells. Therefore, anthocyanins might be recommended as active ingredients for cosmetic and nutraceutical industry. Graphical Abstract ᅟ.

Influence of opacity on the color stability of a nanocomposite.

OBJECTIVE: The aim of this study was to evaluate the color stability in relation to the opacity of the nanocomposite Filtek Ultimate (3M ESPE), by immersing the specimens in different types of natural and artificial staining solutions. MATERIAL AND METHODS: Eighty disks of the shades A1 body (A1B), A1 dentine (A1D), A1 enamel (A1E), and white enamel (WE) (n = 4) of the nanocomposite Filtek Ultimate (3M ESPE) were immersed in staining solutions Orange II, Amaranth, coffee, tea, and artificial saliva. Color coordinates Commission Internationale de l'éclairage (CIE) L*a*b* were collected before and after immersion at 4, 6, 12, 24 h and 7 days. Two-way repeated measurements ANOVA was used in order to assess the effect of immersion time, staining solutions, and materials on CIE L*a*b* parameters, translucency parameter (TP), and color difference (ΔE*). For comparisons between staining solutions and materials, pairwise contrasts adjusted by Bonferroni method were used. RESULTS: The color difference (ΔE*) after 7 days of immersing in staining solution ranged between 0.9 and 15.8. The highest ΔE* after 7 days was obtained for WE, followed by A1E, A1B, and A1D (for all of the immersion solutions, except coffee). There were differences among staining solutions regarding the induced color changes. Coffee induced the most pronounced color differences. However, Orange II, Amaranth, and artificial saliva generated similar behavior in time, for all tested materials. CONCLUSIONS: No statistically significant differences were found among various opacities of Filtek Ultimate regarding the ΔE*, TP, ΔL*, and Δb* overtime. In contrast, Δa* was significantly affected by the type of material. CLINICAL RELEVANCE: The purpose of this study was to predict the color change of different layers of composites, in cases of complex stratified dental restorations.