OBJECTIVES: The purpose of this study was to assess the color change of three types of composite resins exposed to coffee and cola drink, and the effect of repolishing on the color stability of these composites after staining. MATERIALS AND METHODS: Fifteen specimens (15 mm diameter and 2 mm thick) were fabricated from microhybrid (Esthet-X; Dentsply and Filtek Z-250; 3M ESPE) and high-density hybrid (Surefil; Dentsply) composites, and were finished and polished with aluminum oxide discs (Sof-Lex; 3M ESPE). Color of the specimens was measured according to the CIE L*a*b* system in a refection spectrophotometer (PCB 6807; BYK Gardner). After baseline color measurements, 5 specimens of each resin were immersed in different staining solutions for 15 days: G1 - distilled water (control), G2 - coffee, G3 - cola soft drink. Afterwards, new color measurement was performed and the specimens were repolished and submitted to new color reading. Color stability was determined by the difference (ΔE) between the coordinates L*, a*, and b* obtained from the specimens before and after immersion into the solutions and after repolishing. RESULTS: There was no statistically signifcant difference (ANOVA, Tukey's test; p>0.05) among the ΔE values for the different types of composites after staining or repolishing. For all composite resins, coffee promoted more color change (ΔE>3.3) than distilled water and the cola soft drink. After repolishing, the ΔE values of the specimens immersed in coffee decreased to clinically acceptable values (ΔE<3.3), but remained signifcantly higher than those of the other groups. CONCLUSIONS: No signifcant difference was found among composite resins or between color values before and after repolishing of specimens immersed in distilled water and cola. Immersing specimens in coffee caused greater color change in all types of composite resins tested in this study and repolishing contributed to decrease staining to clinically acceptable ΔE values.
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机译：目的：本研究的目的是评估三种类型的复合树脂在咖啡和可乐饮料中的颜色变化，以及再抛光对这些复合物染色后颜色稳定性的影响。材料与方法：用微型混合动力车（Esthet-X; Dentsply和Filtek Z-250; 3M ESPE）和高密度混合动力车（Surefil; Dentsply）复合材料制作了15个样品（直径15毫米，厚度2毫米）。用氧化铝盘（Sof-Lex; 3M ESPE）抛光。样品的颜色根据CIE L * a * b *系统在分光光度计（PCB 6807; BYK Gardner）中测量。进行基线颜色测量后，将每种树脂的5个样品浸入不同的染色溶液中15天：G1-蒸馏水（对照），G2-咖啡，G3-可乐软饮料。之后，进行新的颜色测量，并对样品进行抛光，并进行新的颜色读取。颜色稳定性由在浸入溶液之前和之后以及再抛光后从样品获得的坐标L *，a *和b *之差（ΔE）决定。结果：在染色或再抛光后，不同类型复合材料的ΔE值之间无统计学差异（ANOVA，Tukey检验; p> 0.05）。对于所有复合树脂，咖啡比蒸馏水和可乐软饮料能促进更多的颜色变化（ΔE> 3.3）。再抛光后，浸泡在咖啡中的样品的ΔE值降低到临床可接受的值（ΔE<3.3），但仍然明显高于其他组。结论：在浸没在蒸馏水和可乐中的试样再抛光之前和之后，复合树脂之间或色值之间没有发现显着差异。将样品浸入咖啡中会导致本研究中测试的所有类型的复合树脂的颜色发生较大变化，并且重新抛光有助于将污点减少至临床可接受的ΔE值。
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