Kourtis Stefanos G, Tripodakis Aris-Petros, Doukoudakis Asterios A
National and Kapodestrian University of Athens, 17121 Athens, Greece.
J Prosthet Dent. 2004 Nov;92(5):477-85. doi: 10.1016/j.prosdent.2004.08.012.
Color matching between natural teeth, shade guides, and metal-ceramic restorations is a common clinical problem. Difficulties related to color matching arise from structural differences that exist between metal-ceramic crowns and natural teeth, the limited range of available ceramic shades, inadequate shade guides, different types of metal alloys, and varying compositions of ceramic materials.
The aim of this study was to investigate the influence of various metal alloys and 2 porcelains on the final color of metal-ceramic complex. Material and methods Four commercial alloys for metal-ceramic restorations, a Ni-Cr (Thermobond), a Co-Cr (Wirobond), a Pd-rich noble (Cerapal-2), and a high noble Au-alloy (V-Delta) were combined with 2 porcelains (Vita Omega and Ceramco Silver) in metal-ceramic specimens with a standardized thickness of layers. Five disc-shaped (10 x 1 mm) specimens were prepared for each alloy/porcelain combination. Only opaque and dentin layers were applied (shade A3). The specimens were analyzed with a spectrophotometer, and data were obtained in the CIE Lab color system. The recorded data were analyzed with a 2-way multiple analysis of variance , a pair-wise comparison of group means (Student's t test), and finally, a categorical regression analysis of variance (CATREG) (alpha=.01).
The types of alloy substrate and overlying porcelain significantly affected the color (P < .01). Au and Co-Cr alloys were found to be brighter (higher L* values) than the Ni-Cr and the Pd alloys ( P <.01, SE 0.239). Ceramco porcelain was found to be most red (higher a* values) of all tested alloys ( P <.01). Gold and Pd alloys caused a yellow shift to the metal-ceramic color compared to the Ni-Cr and the Co-Cr alloys with both porcelains ( P < .01, SE 0.165). The detected color differences were visually perceptible for some alloy-porcelain combinations.
The final color of metal ceramic specimens was influenced both from the type of alloy substructure and from the type of overlying porcelain.
天然牙、比色板与金属烤瓷修复体之间的颜色匹配是一个常见的临床问题。颜色匹配方面的困难源于金属烤瓷冠与天然牙之间存在的结构差异、可用陶瓷颜色范围有限、比色板不足、不同类型的金属合金以及陶瓷材料的不同成分。
本研究的目的是调查各种金属合金和两种瓷对金属烤瓷复合体最终颜色的影响。材料与方法 将四种用于金属烤瓷修复体的商用合金，即镍铬合金（Thermobond）、钴铬合金（Wirobond）、富钯贵金属合金（Cerapal - 2）和高贵金属金合金（V - Delta）与两种瓷（维他欧米伽瓷和西拉姆科银瓷）组合，制成具有标准化层厚度的金属烤瓷试件。每种合金/瓷组合制备五个圆盘形（10×1毫米）试件。仅施加不透明层和牙本质层（A3色）。用分光光度计对试件进行分析，并在CIE Lab颜色系统中获取数据。对记录的数据进行双向多因素方差分析、组均值的成对比较（学生t检验），最后进行分类回归方差分析（CATREG）（α = 0.01）。
合金基底类型和覆盖瓷类型对颜色有显著影响（P < 0.01）。发现金合金和钴铬合金比镍铬合金和钯合金更亮（L值更高）（P < 0.01，标准误0.239）。在所有测试合金中，发现西拉姆科瓷最红（a值更高）（P < 0.01）。与镍铬合金和钴铬合金相比，金合金和钯合金在两种瓷的情况下都会使金属烤瓷颜色产生黄移（P < 0.01，标准误0.165）。对于某些合金 - 瓷组合，检测到的颜色差异在视觉上是可察觉的。
金属烤瓷试件的最终颜色受合金亚结构类型和覆盖瓷类型的影响。
