Wang Jian, Lin Jin, Seliger Alison, Gil Mindy, da Silva John D, Ishhikawa-Nagai Shigemi
Department of Restorative Dentistry and Biomaterials Sciences, Harvard School of Dental Medicine, Boston, MA, USA.
J Esthet Restor Dent. 2013 Aug;25(4):254-62. doi: 10.1111/j.1708-8240.2012.00538.x. Epub 2012 Sep 14.
The final color of all-ceramic crowns is influenced by the color of both the remaining tooth structure and the surrounding gingival tissue. The optical effects of gingival tissue on an all-ceramic crown have never been fully studied.
The purpose of this study is to investigate the effects of gingival color on ceramic crowns in the cervical region. materials and methods: Thirty-one all-ceramic crowns of differing shades were included in this study. Using a spectrophotometer, the color values of each crown were measured on a typodont in the absence of an artificial gingiva (control group) and in the presence of an artificial gingiva (test group). CIELAB color coordinates (L*, a*, b*) were collected from three regions of the cervical area in descending order from the gingival margin (upper region, middle region, and lower region). Color difference values (ΔE*) were calculated for each cervical region between the test and control groups. ΔE* between the test and control groups from the upper to lower cervical regions was also compared with each other. The statistical analysis was performed using the student t-test and one-way analysis of variance (ANOVA) test.
The mean ΔE* values between the test group and control group at the upper, middle, and lower cervical regions were 5.8, 2.8, and 1.8, respectively. Significant color differences between the test and control group were detected in all three incremental regions (p < 0.001 at ΔE* = 1.6 threshold), with all color coordinates (L*, a*, and b*) contributing significantly to the color differences in these regions (p < 0.001). The color variations in the cervical area also varied significantly from the upper region to the lower region, with L* and a* contributing most to the differences.
The presence of artificial gingiva is a critical factor in precise color matching and color reproduction for all-ceramic crowns.
Gingival tissue has significant optical effects on the color of all-ceramic crowns at the cervical areas; therefore, it is suggested that artificial gingiva be used by both dentists and ceramists while matching and replicating tooth color with ceramic restorations. (J Esthet Restor Dent ••:••-••, 2012).
全瓷冠的最终颜色受剩余牙体组织和周围牙龈组织颜色的影响。牙龈组织对全瓷冠的光学效应尚未得到充分研究。
本研究的目的是调查牙龈颜色对颈部区域陶瓷冠的影响。
本研究纳入了31个不同色度的全瓷冠。使用分光光度计，在无人工牙龈（对照组）和有人工牙龈（试验组）的情况下，在模型牙上测量每个冠的颜色值。从牙龈边缘按降序从颈部区域的三个区域（上部区域、中部区域和下部区域）收集CIELAB颜色坐标（L*、a*、b*）。计算试验组和对照组之间每个颈部区域的颜色差值（ΔE*）。还比较了试验组和对照组从上颈部区域到下颈部区域的ΔE*。使用学生t检验和单因素方差分析（ANOVA）进行统计分析。
试验组和对照组在上、中、下颈部区域的平均ΔE值分别为5.8、2.8和1.8。在所有三个增量区域均检测到试验组和对照组之间存在显著颜色差异（在ΔE = 1.6阈值时p < 0.001），所有颜色坐标（L*、a和b）对这些区域的颜色差异有显著贡献（p < 0.001）。颈部区域的颜色变化从上区域到下区域也有显著差异，L和a对差异贡献最大。
人工牙龈的存在是全瓷冠精确颜色匹配和颜色再现的关键因素。
牙龈组织对颈部区域全瓷冠的颜色有显著光学效应；因此，建议牙医和技师在使用陶瓷修复体匹配和复制牙齿颜色时使用人工牙龈。（《美容修复牙科杂志》••:•• - ••，2012年）
