Douglas R Duane, Brewer Jane D
School of Dental Medicince, Southern Illinois University, Alton, Ill, USA.
J Prosthet Dent. 2003 Oct;90(4):339-46. doi: 10.1016/s0022-3913(03)00513-4.
Many investigations in the field of metal ceramics have examined materials, manipulative variables, and the relationship of these factors to a restoration's color. However, the effect of the artistic component of restoration fabrication is not known.
The purpose of this study was to determine through instrumental colorimetry the variability in color reproduction for metal ceramic crowns fabricated by commercial dental laboratory technicians.
Fifty metal ceramic crowns were fabricated on standardized metal frameworks to the same shade specifications by 5 commercial dental laboratories (n=10). Laboratory prescriptions requested that the technician match the shade and translucency of a provided Vita Lumin A3.5 shade tab. Technicians used the porcelain and technique of their own selection to match the tab. Color differences were determined by use of a colorimeter between crowns and the prescribed shade tab at middle and incisal sites. Analysis of variance was used to determine whether differences in color reproduction existed among laboratories. Where statistically significant interactions existed, the Tukey honestly significant difference test was used to determine significant differences between laboratories according to sites (alpha=.05).
Color reproduction was significantly different (P <.0001) among laboratories for both sites. Mean color difference from shade tabs ranged from 3.5 to 11.1 DeltaE units. All laboratories were better at matching shades in the incisal third of the crown.
Within the limitations of this study, the ability to reproduce the color of the target shade tab differed among laboratories. Most crowns fabricated by the laboratories in this study, when compared to the prescribed shade tab, were above the clinical threshold for an acceptable shade match under intraoral conditions (DeltaE 3.7).
金属陶瓷领域的许多研究都考察了材料、操作变量以及这些因素与修复体颜色之间的关系。然而，修复体制作中艺术成分的影响尚不清楚。
本研究的目的是通过仪器比色法确定商业牙科实验室技术人员制作的金属陶瓷冠在颜色再现方面的变异性。
5家商业牙科实验室（n = 10）在标准化金属框架上按照相同的色度规格制作了50个金属陶瓷冠。实验室处方要求技术人员匹配所提供的Vita Lumin A3.5色标卡的色度和透明度。技术人员使用自己选择的瓷粉和技术来匹配色标卡。使用色差仪在冠的中部和切端部位测定冠与规定色标卡之间的颜色差异。采用方差分析来确定各实验室之间在颜色再现方面是否存在差异。当存在统计学上显著的交互作用时，使用Tukey真实显著差异检验来根据部位确定各实验室之间的显著差异（α = 0.05）。
两个部位在各实验室之间颜色再现均有显著差异（P <.0001）。与色标卡的平均颜色差异范围为3.5至11.1 ΔE单位。所有实验室在匹配冠切端三分之一处的色度方面表现更好。
在本研究的局限性范围内，各实验室在再现目标色标卡颜色的能力上存在差异。与规定色标卡相比，本研究中各实验室制作的大多数冠在口腔内条件下的可接受色度匹配临床阈值（ΔE 3.7）之上。
