Discoloration of Resin Composites Induced by Coffee and Tomato Sauce and Subjected to Surface Polishing: An In Vitro Study

Abstract

Departmental sources Background: The purpose of this study is to evaluate and compare color stability of 3 resin based restorative materials when immersed into staining media at 0, 3, 30, 45, 60, and 75 days, and to assess the efficacy of surface polishing in reducing possible discoloration. Material/Methods: Ninety composite discs were prepared in a custom-made mold (5 mm diameter and 2 mm thick) from 3 different light cured composites (Filtek™ Z250, Harmonize™, and G-aenial). Color differences of all specimens were measured by a spectrophotometer according to the CIE L*a*b* system. After baseline color measurements, 30 discs from each composite group were randomly divided into 3 subgroups of 10 specimens each. Subgroups (n=10) were immersed for 75 days into different staining solutions: coffee, tomato sauce, and distilled water (control). Solutions were changed every week and color measurements were repeated every 15 days. At day 75, color measurements of the specimens were performed before and after surface polishing with aluminum oxide discs. The experimental data were statistically evaluated using repeated measures one-way ANOVA test followed by Tukey's multiple pairwise comparison with a significance level of 5%. Results: Of the 3 composites, G-aenial reported the highest color change deviation when immersed into coffee (DE=8.674), and tomato sauce (DE=7.737) at day 75, followed by Harmonize that also exhibited a significant difference for coffee (DE=4.7) and tomato sauce (DE=3.8) when compared to distilled water. While Filtek™ Z250 did not show any significant difference between the 3 storage solutions (P>0.05). Only G-aenial had significant color change (P<0.05) after polishing with aluminum oxide discs for all tested samples, whereas Filtek™ Z250 and Harmonize presented no significant difference after surface polishing (P>0.05). Conclusions: Under the tested experimental conditions, Filtek™ Z250, among the 3 resin-based composites, exhibited the highest color stability when subjected to coffee and tomato sauce as well. Whereas, G-aenial presented the highest color deviation when immersed in both staining media. Surface polishing effectively reduced coffee and tomato sauce discolorations for G-aenial's specimens and had no significant effect regarding Filtek™ Z250 and Harmonize.

Importance of color stability of the esthetic restoration materials

“…In addition to that, smoking has also been counted as a factor. 17 Several pathologies have either direct or indirect affection on the color of teeth. As in some diseases, the enamel is being affected, causing it to lose its whiteness.…”

“…15,16 Coffee pigmentation results from both surface removal of colorant and absorption in the underground layer, which is presumably related to the polymeric phase of the resin's compliance with a yellowcolored compound present in coffee, which may explain the increase in b* yellow-yellow concentrations. 17,18 The effectiveness of polymerization may affect discoloration because the higher the degree of conversion, the fewer residual monomers are available to create colored degradation products. According to the manufacturers' statistics, complementary polymerization conducted by light and heat (Targis) and heat, pressure, and vacuum (belleGlassTM) increase the conversion rate of both materials by 80% and 98.5%, respectively, which is consistent with our results.…”

“…21 This extra polishing can relieve existing tension on the interface matrix/filler particles, which is responsible for reducing the subsurface layer, making microcracks and gaps more visible, and allowing color penetration. 17 Leinfelder et al mentioned heat, pressure, and vacuum as variables that contribute to polymerization efficiency. 22 The Targis and belleGlassTM results indicated a considerably less color shift than the Tetric Ceram® and Resilab results.…”

“…Assaf et al and Fonseca et al on the other hand, demonstrated that extra polymerization does not apply to all objects and may be compensated for by a prolonged communication that lasts one week after the first scanning. 17,19 In second-generation composite resins, the inclusion of more active monomers can change the polymerization reaction, enhancing the kinetics of the cross-linking process. Regarding material characteristics related to total color variation, Tetric Ceram® and Resilab Master did not exhibit statistical differences, with significant E values However, compared to other direct restorative materials, the composite resin Tetric Ceram showed outstanding color stability in earlier tests, demonstrating the advantages of second-generation indirect composites.…”

“…Even though their findings were over the well-known limit, they were still within the maximum limit indicated by Assaf et al after two weeks of experimental therapy. 17 Indirect Composition Targis (E=3.85) and belleGlass (E=3.40) may be regarded clinically appropriate. However, second-generation particles behaved differently, making a general response to color stability impossible, which may explain the conflicting results reported in earlier research.…”