Prosthodontics Department, Faculty of Dentistry Mahidol University, Bangkok, Thailand.
J Adv Prosthodont. 2013 Aug;5(3):319-25. doi: 10.4047/jap.2013.5.3.319. Epub 2013 Aug 31.
The objective of this study was to determine the effect of the color of a background substructure on the overall color of a zirconia-based all-ceramic crown.
Twenty one posterior zirconia crowns were made for twenty subjects. Seven premolar crowns and six molar crowns were cemented onto abutments with metal post and core in the first and second group. In the third group, eight molar crowns were cemented onto abutments with a prefabricated post and composite core build-up. The color measurements of all-ceramic crowns were made before try-in, before and after cementation. A repeated measure ANOVA was used for a statistical analysis of a color change of all-ceramic crowns at α=.05. Twenty four zirconia specimens, with different core thicknesses (0.4-1 mm) were also prepared to obtain the contrast ratio of zirconia materials after veneering.
L() , a() , and b() values of all-ceramic crowns cemented either on a metal cast post and core or on a prefabricated post did not show significant changes (P>.05). However, the slight color changes of zirconia crowns were detected and represented by ΔE() ab values, ranging from 1.2 to 3.1. The contrast ratios of zirconia specimens were 0.92-0.95 after veneering.
No significant differences were observed between the L() , a() , and b() values of zirconia crowns cemented either on a metal cast post and core or a prefabricated post and composite core. However, the color of a background substructure could affect the overall color of posterior zirconia restorations with clinically recommended core thickness according to ΔE() ab values.
本研究旨在确定背景子结构颜色对氧化锆基全瓷冠整体颜色的影响。
为 20 名受试者制作了 21 个后牙氧化锆全瓷冠。第一组和第二组的 7 个前磨牙冠和 6 个磨牙冠用金属桩核粘接到基台上，第三组的 8 个磨牙冠用预制桩和复合核构建体粘接到基台上。在试戴前、粘固前和粘固后分别对全瓷冠的颜色进行测量。采用重复测量方差分析对全瓷冠颜色变化进行统计学分析，α 值为 0.05。还制备了 24 个具有不同核厚度（0.4-1mm）的氧化锆试件，以获得贴面后氧化锆材料的对比度比值。
粘接到金属铸造桩核或预制桩上的全瓷冠的 L()、a()和 b()值均无显著变化（P＞0.05）。然而，检测到氧化锆冠的轻微颜色变化，用ΔE() ab 值表示，范围为 1.2-3.1。贴面后氧化锆试件的对比度比值为 0.92-0.95。
粘接到金属铸造桩核或预制桩和复合核上的氧化锆冠的 L()、a()和 b()值之间无显著差异。然而，根据ΔE() ab 值，背景子结构的颜色可能会影响临床推荐核厚度的后牙氧化锆修复体的整体颜色。
