Assistant Professor, Department of Prosthodontics, School of Dentistry, Lorestan University of Medical Sciences, Khorramabad, Iran.
Instructor, Dentist, student Research Committee, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
J Prosthet Dent. 2024 Sep;132(3):605-611. doi: 10.1016/j.prosdent.2022.06.024. Epub 2022 Sep 15.
Matching the shade selected and the final color of a ceramic restoration is challenging, and studies on matching monolithic ceramics to the shade selected are lacking.
The purpose of this in vitro study was to compare the color match of monolithic lithium disilicate (LDS), zirconia-reinforced lithium silicate (ZLS), presintered zirconia-reinforced lithium silicate (PS-ZLS), polymer-infiltrated ceramic network (PICN), and multilayer zirconia with the 3 modes of the VITA Classical shade guide.
This study was performed on 50 rectangular plates (14×12×1 mm) of 5 types of ceramics with A2 shade (n=10). Zirconia specimens were evaluated in 3 locations: incisal, medial, and cervical thirds. The color coordinates of the specimens of all 7 groups were measured on #3 and #8 Ivoclar Natural Die Color material by using a reflective spectrophotometer. The color coordinates of A2 VITA shade were measured in 5 modes: without backing placed in specimen holder, shade tab on the backgrounds #3 and #8, and 1-mm-thick shade tab on the backgrounds #3 and #8. The color difference of each specimen with 3 modes of A2 shade (without backing and on similar backgrounds) was calculated by using the ΔE formula, and comparison among groups was performed by using 2-way ANOVA and Tamhane post hoc tests. The comparison of ΔE between the values obtained from backgrounds #3 and #8 was performed by using the independent t test (α=.05).
In both backgrounds, statistically significant differences were found between the studied groups and VITA shade (P<.001). In most situations, the amount of color difference was lowest for the "shade tab on the backgrounds" mode. On background #3, the highest color difference was related to ZLS (6.48 ±0.23), and the lowest values were observed in the PICN group (1.02 ±0.31). On background #8, the highest color difference was related to ZLS compared with the "without backing" mode (8.62 ±0.27), and the lowest values were reported for ZLS compared with the "shade tab on the backgrounds" mode (1.27 ±0.44). The independent t test showed a statistically significant color difference on the 2 different backgrounds for all situations (P<.001).
Color selection of monolithic ceramics with the VITA Classical shade guide is improved by placing the VITA tabs on a similar background. Background color has a significant effect on the final shade of the monolithic ceramics. Choosing the correct color for LDS, ZLS, and PS-ZLS requires more care than for PICN and zirconia.
匹配所选色调和陶瓷修复体的最终颜色具有挑战性，而且缺乏对整体陶瓷与所选色调匹配的研究。
本体外研究的目的是比较整体锂硅玻璃陶瓷（LDS）、氧化锆增强锂硅玻璃陶瓷（ZLS）、预烧结氧化锆增强锂硅玻璃陶瓷（PS-ZLS）、聚合物渗透陶瓷网络（PICN）和多层氧化锆与 VITA 经典比色指南的 3 种模式的颜色匹配。
本研究对 5 种 A2 色调的陶瓷矩形板（14×12×1mm）各进行了 10 个样本（n=10）。氧化锆样本在切缘、中 1/3 和颈 1/3 3 个部位进行评估。用反射分光光度计测量所有 7 组样本在 Ivoclar Natural Die Color 材料 #3 和 #8 上的颜色坐标。在 5 种模式下测量 A2 VITA 色调的颜色坐标：无背景放置在样本架上、比色标签放在背景 #3 和 #8 上、1mm 厚的比色标签放在背景 #3 和 #8 上。使用 ΔE 公式计算每个样本在 3 种 A2 色调模式（无背景和类似背景）下的色差，并通过双因素方差分析和 Tamhane 事后检验比较组间差异。使用独立 t 检验（α=.05）比较背景 #3 和 #8 上获得的 ΔE 值之间的差异。
在两种背景下，研究组与 VITA 色调之间存在统计学显著差异（P<.001）。在大多数情况下，“比色标签放在背景上”模式的色差最小。在背景 #3 上，最高的色差与 ZLS 相关（6.48±0.23），而 PICN 组的最低值为 1.02±0.31。在背景 #8 上，与“无背景”模式相比，ZLS 相关的色差最高（8.62±0.27），而与“比色标签放在背景上”模式相比，ZLS 的最低值为 1.27±0.44。独立 t 检验显示在所有情况下两种不同背景之间的颜色差异均具有统计学意义（P<.001）。
通过将 VITA 标签放在类似背景上，使用 VITA 经典比色指南选择整体陶瓷的颜色可得到改善。背景颜色对整体陶瓷最终色调有显著影响。对于 LDS、ZLS 和 PS-ZLS，需要比 PICN 和氧化锆更小心地选择正确的颜色。
