Lee Yong-Keun, Cha Hyun-Suk, Ahn Jin-Soo
Department of Dental Biomaterials Science and Dental Research Institute, College of Dentistry, Seoul National University, Seoul, Korea.
J Prosthet Dent. 2007 May;97(5):279-86. doi: 10.1016/j.prosdent.2007.03.010.
Color of an all-ceramic restoration is the result of interaction between core and veneer ceramics. However, the influence on color of the different types of all-ceramic core and veneer combinations at clinically relevant thicknesses is not well understood.
The purpose of this study was to measure the layered color of all-ceramic core and veneer combinations with the thickness of the core set as the clinically minimum thickness to mask the background, and the thickness of the veneer set as the remaining available thickness within a clinically allowable thickness.
The A2-corresponding shade of 7 all-ceramic core materials, and 1 sintering ceramic and 1 alloy core as references, were prepared in clinically minimum thicknesses (0.4 to 0.8 mm) to mask the background (n=7). The A2 and A3 corresponding shades of each recommended veneer ceramic were used to fabricate specimens that were 1.5 mm thick. The color of the core, veneer, and layered specimens was measured with a reflection spectrophotometer. Two-way ANOVA with the independent variables of the types of core and veneer ceramics on the layered color was used to analyze the data (alpha=.05). The influence of the color coordinates in the core and veneering ceramics on the layered color was analyzed with multiple regression analysis.
CIE L( *), a( *), b( *), and C( *)(ab) values of A2- or A3-veneer layered specimens were influenced significantly by the combination of core and veneer ceramics (P<.001). The CIE L( *) values of layered specimens were primarily influenced by the CIE L( *) values of the core ceramic (P<.001). The other 3 parameters were primarily influenced by each corresponding parameter of veneer ceramic, based on multiple regression analyses (P<.001).
The layered color of all-ceramic core and veneer ceramics in the clinically allowable thickness was different even when the same shade, keyed to a VITA guide, of core and veneer ceramics were layered. The color difference between each pair of A2- or A3-veneered specimens by the combination of core and veneer ceramics ranged from 1.4 to 5.6 DeltaE( *)(ab) units.
全瓷修复体的颜色是核瓷和饰面瓷之间相互作用的结果。然而，对于临床相关厚度下不同类型的全瓷核瓷和饰面瓷组合对颜色的影响，人们尚未完全了解。
本研究的目的是测量全瓷核瓷和饰面瓷组合的分层颜色，其中核瓷的厚度设定为临床可接受的最小厚度以遮盖底色，饰面瓷的厚度设定为临床允许厚度内的剩余可用厚度。
制备7种全瓷核材料的A2对应色，以及1种烧结陶瓷和1种合金核作为对照，厚度均为临床最小厚度（0.4至0.8毫米）以遮盖底色（n = 7）。每种推荐的饰面瓷的A2和A3对应色用于制作厚度为1.5毫米的试件。使用反射分光光度计测量核瓷、饰面瓷和分层试件的颜色。采用双向方差分析，以核瓷和饰面瓷类型作为自变量，对分层颜色进行分析（α = 0.05）。通过多元回归分析核瓷和饰面瓷中的颜色坐标对分层颜色的影响。
A2或A3饰面分层试件的CIE L(), a(), b(), 和C()(ab)值受核瓷和饰面瓷组合的显著影响（P <.001）。分层试件的CIE L()值主要受核瓷的CIE L()值影响（P <.001）。基于多元回归分析，其他3个参数主要受饰面瓷各自对应参数的影响（P <.001）。
即使核瓷和饰面瓷按照VITA比色板选择相同的色号，在临床允许厚度下，全瓷核瓷和饰面瓷的分层颜色仍然不同。核瓷和饰面瓷组合的每对A2或A3饰面试件之间的色差范围为1.4至5.6 ΔE(*)(ab)单位。
