Department of Operative Dentistry, School of Dentistry, Tehran University of Medical Sciences, Dental Research Center, Tehran, Iran.
Oper Dent. 2010 Nov-Dec;35(6):605-9. doi: 10.2341/09-161-L.
The color stability of resin cements plays a major role in the esthetic performance of porcelain laminate veneers. Some dual-polymerizable resin cements used to bond porcelain laminates were shown to undergo color changes during service. Some recently produced cements are described as being color stable, but scientific data are not available.
The current study evaluated the effect of accelerated aging on the color and opacity of resin cements. The hypothesis was that the auto-polymerizing cements would show less color and opacity stability.
Forty (0.7 x 18 mm) feldspathic porcelain disks were prepared and divided into four equal groups. The resin cements were bonded to the disks by application of an identical load of 2.5 kilograms, and they were polymerized according to the manufacturer's instructions. The groups were: Variolink Veneer (light-polymerizing), Variolink II (light-polymerizing), Variolink II (dual-polymerizing) and Multilink (auto-polymerizing). A spectrophotometer was used to measure the following color parameters in the CIE Lab* color space on a black and white background: deltaa*, deltab*, deltaL*, deltaC, deltaH, deltaE and deltaCR (contrast ratio). The measurements were performed before and after aging. Paired t- and one-way ANOVA tests were used to analyze the data (alpha = .05).
None of the groups showed significant differences in deltaE before and after aging (p > .05); deltaE remained in the range of clinical acceptance (deltaE < 3.3). All of the cements became more opaque, while deltaCR (difference in contrast ratio) was significantly different (p = .004). The auto-polymerized cement showed an increase in opacity.
The studied cements behaved acceptably according to deltaE, but they became more opaque after aging.
The studied cements can ensure color stability when used to cement porcelain laminate veneers, but the change in opacity can affect clinical results. Auto polymerizing cements become more opaque with aging; therefore, porcelain restorations may lose their match with other teeth.
树脂水门汀的颜色稳定性对瓷贴面的美观性能起着重要作用。一些用于粘结瓷贴面的双固化树脂水门汀在使用过程中会发生颜色变化。一些最近生产的水门汀被描述为颜色稳定，但没有科学数据。
本研究评估加速老化对树脂水门汀颜色和不透明度的影响。假设自固化水门汀的颜色和不透明度稳定性较差。
制备 40 个（0.7 x 18mm）长石质瓷盘，并将其分为四等份。将树脂水门汀按相同的 2.5 公斤负载应用于磁盘上，并按照制造商的说明进行聚合。将各组分别为：Variolink Veneer（光固化）、Variolink II（光固化）、Variolink II（双固化）和 Multilink（自固化）。使用分光光度计在黑白背景下测量 CIE Lab颜色空间中的以下颜色参数：deltaa、deltab*、deltaL*、deltaC、deltaH、deltaE 和 deltaCR（对比度比）。在老化前后进行测量。使用配对 t 检验和单因素方差分析对数据进行分析（alpha =.05）。
老化前后，各组的 deltaE 均无显著差异（p >.05）；deltaE 仍在临床可接受范围内（deltaE < 3.3）。所有水门汀的不透明度都增加了，而 deltaCR（对比度比的差异）则有显著差异（p =.004）。自固化水门汀的不透明度增加。
根据 deltaE，研究中的水门汀表现可接受，但老化后变得更不透明。
研究中的水门汀用于粘结瓷贴面时可以保证颜色稳定性，但老化后不透明度的变化会影响临床效果。自固化水门汀随老化而变得更不透明；因此，瓷修复体可能会失去与其他牙齿的匹配。
