Oper Dent. 2019 Sep/Oct;44(5):488-498. doi: 10.2341/18-016-L. Epub 2019 Jan 23.
The aim of this study was to evaluate the effectiveness of the layering technique to mask a discolored background (C4) after one year of water aging. The technique was used with three resin composite restorative systems (IPS Empress Direct, Charisma Diamond, and Filtek Z350XT). Ninety 1.5-mm-thick specimens were divided into groups and subgroups according to the restorative system and resin composite shade combination used in the layering technique (enamel, body, and dentin). The color measurements were made by reflection spectrophotometer (SP60, EX-Rite) over the C4 substrate at two time points: after 24-hour water immersion (T) and after one-year water aging (T). The masking ability was evaluated by calculating the ΔE between an inherent color background and a C4 background at T and T. CIELAB and CIEDE2000 formulas were used for comparative analysis between T and T color measurements. Analysis of variance and Turkey's test (=0.05) were performed to analyze ΔE and ΔE mean values. The Z350XT restorative system presented adequate masking ability in the combinations of 0.5 mm body + 1.0 mm dentin, 0.5 mm enamel + 1.0 mm dentin, and 1.5 mm dentin after 24-hour water immersion. The masking ability was affected negatively by water aging in most of the combinations. The IPS Empress Direct was the only system that remained stable after aging in the combinations of 0.5 mm enamel + 1.0 mm dentin and + 1.5 mm dentin (=0.05 and =0.47 for CIELAB; =0.15 and =0.51 for CIEDE2000), although it did not present adequate masking ability in both time points. None of the combinations of any system presented adequate masking ability after prolonged water aging.
本研究旨在评估分层技术在经过一年水老化后掩盖变色背景（C4）的效果。该技术用于三种树脂复合材料修复系统（IPS Empress Direct、Charisma Diamond 和 Filtek Z350XT）。将 90 个 1.5 毫米厚的样本根据修复系统和分层技术中使用的树脂复合材料颜色组合（釉质、体部和牙本质）分为组和亚组。在 C4 基底上，使用反射分光光度计（SP60，EX-Rite）在两个时间点（T 和 T）测量颜色：24 小时水浸泡后（T）和一年水老化后（T）。通过计算固有颜色背景和 C4 背景在 T 和 T 之间的 ΔE 来评估掩蔽能力。CIELAB 和 CIEDE2000 公式用于比较 T 和 T 之间的颜色测量。使用方差分析和 Turkey's 检验（=0.05）分析 ΔE 和 ΔE 平均值。Z350XT 修复系统在 24 小时水浸泡后，0.5 毫米体部+1.0 毫米牙本质、0.5 毫米釉质+1.0 毫米牙本质和 1.5 毫米牙本质的组合中具有足够的掩蔽能力。在大多数组合中，水老化会对掩蔽能力产生负面影响。IPS Empress Direct 是唯一在 0.5 毫米釉质+1.0 毫米牙本质和+1.5 毫米牙本质的组合中在老化后保持稳定的系统（CIELAB 为=0.05 和=0.47；CIEDE2000 为=0.15 和=0.51），尽管在两个时间点都没有足够的掩蔽能力。任何系统的组合在长时间水老化后都没有足够的掩蔽能力。
