三种烤瓷修复体的色度学研究

目的：研究3种烤瓷修复体之间及与Vita标准比色片之间的色差。方法：实验组为In-Ceram全瓷修复体（A组）、钛金属烤瓷修复体（B组）、镍铬合金烤瓷修复体（C组）。对照组为VitaA2标准比色片（D组）。实验组每组10个圆盘状试件，每个试件直径15mm。玻璃渗透氧化铝底层和金属底层均厚1mm。使用VitaA2瓷粉，遮色瓷厚0．2mm，体瓷厚1mm，透明瓷厚0．4mm，按操作常规烧制。使用Spectrascan PR650分光光谱测色仪测试试件和VitaA2标准比色片。颜色系统为CIE1976，L^＊a^＊^b^＊色度系统。结果：各实验组之间除A-C组的a^＊值外，其余的色度值之间均有显著差异。3组之间的色差范围为3．25-8．50ΔE。与标准比色片相比，除C-D组的L^＊值和b^＊值及A-D组的b^＊值外，其余色度值之间均有显著差异。实验组与标准比色片的色差范围为2．29-8．31ΔE。结论：实验组之间及与标准比色片之间色差过大，应进一步改进这3种烤瓷修复体的颜色匹配性能。     

背景及测量位置对前牙测色的影响

目的：比较人类离体中切牙在不同的背景下（黑、白、粉红色）用接触式色彩色差计测量不同位置所得的色度值.方法：应用Minolta CR-321测色仪在3种不同的背景下对10颗人类离体中切牙进行测量,每牙测7点并记录其CIE1976L^＊a^＊b^＊值.结果：1）在不同的背景下,△E12 （代表1号位置与2号位置间的色差值）在黑白色背景间有差异（P＜0.05）,但它们与粉红色背景无差异（P＞0.05）;△E13、△E14、△E15、△E16、△E17在3种背景下均无差异（P＞0.05）;同一位置上所测的L^＊值、a^＊值、b^＊值在3种背景下均无差异（P＞0.05）.2）各色差值中,3种背景下的△E13,△E15及黑色背景下的△E12均大于1.5△E（P＜0.05）其余的均小于等于1.5△E（P＞0.05）.结论：本试验表明在无环境光源时,背景色对人中切牙的色度测量影响不大;牙唇面牙冠中1/3正中点的色度值与周围1 mm的范围内各点的色度值相差不大（△E≤1.5）,但距离超过2 mm时它们之间存在明显差异（垂直向各点△E＞1.5）,提示中切牙唇面的颜色在较小的范围内差异较大,甚至达到肉眼所能辨别差异的程度.     

厚度和底色对Solidex树脂颜色影响的实验研究

目的观察厚度和底色对Solidex修复性树脂颜色的影响。方法制作厚度分别为0．8、1．0、1．2、1．4、1．6和1．8mm的Solidex树脂样本，用ShadeEye NCC测色仪分别测定其在金属底层和色度为A3和C3的树脂底层上的L^＊a^＊b^＊值，比较样本在不同厚度和不同底色时的色差并用SPSS分析L^＊a^＊b^＊值的统计学差异。结果Solidex树脂的厚度大于1．6mm时，树脂在三种底色材料上的色差无显著性差异，L^＊a^＊b^＊值无统计学差异。当树脂的厚度小于1．4mm时，三种底色材料上Solidex树脂的色差随厚度的增加而减小，金属底色上的色差较树脂底色时大。Solidex树脂试样的L^＊a^＊b^＊在金属底层和C3色树脂底层上时有显著性差异。结论金属底色对Solidex树脂的颜色影响较树脂底色大。使用Solidex树脂制作美容性修复体时，树脂材料厚度应大于1．6mm以消除底色的影响。     

牙龈色板对比色板色标颜色的影响

目的 通过定量分析比色板色标在附有牙龈色板时色度三属性的变化，分析并预测牙龈色板对视觉比色将产生何种影响。方法 首先选用2组配有牙龈色板的新比色板（Vintage Halo），在统一条件下分别对所有色标进行测色，以CIE L^＊a^＊b^＊系统记录，转换为CIE L^＊C^＊H^＊值。然后将色标分别安装3种牙龈色板（GumL、GumM、GumD）重复以上过程。计算并分析使用牙龈色板前后的色差以及色度三属性的变化情况。结果 统计检验各色标在无牙龈色板、浅色牙龈色板、中色牙龈色板以及深色牙龈色板情况下的测色结果，分析表明安装牙龈色板各实验组色标与空白对照组相比L^＊、C^＊ab值无明显改变，但是H^0ab值明显下降，变化范围：GumL组（0．52～4．49），平均下降2．12；GumM组（0．90～4．80），平均下降2．46；GumD组（0．66～4．41），平均下降2．01。色差变化范围：GumL组（0、77-3．16），平均1．804；GumM组（0．75～3．43），平均1．676；GumD组（0．61～3．68）。平均1．652，但使用不同浓淡颜色牙龈色板的3组间无明显差异。结论 使用牙龈色板时色标颜色出现了较明显改变，色差值达到1．6～1．8，视觉感觉色差很明显，可以影响临床比色结果。     

体瓷厚度与烧结次数对Cercon氧化锆全瓷颜色的影响

目的：探讨不同体瓷厚度和不同烧结次数对Cercon氧化锆全瓷颜色的影响。方法：用氧化锆底瓷材料制作直径为12mm、厚度为0．8mm的圆盘状试件15个,表面涂塑体瓷。根据体瓷厚度的不同分为3组：0．5mm组、1．0mm组和1．5mm组,每组5个。严格按厂家规定的饰面瓷烧结程序对氧化锆试件反复烧结,分别于烧结1次、3次、5次、7次后使用Easyshade电脑比色仪对氧化锆试件的色度学参数进行测量,记录所得L^＊、a^＊、b^＊值。并计算色差△E：△E=[（△L^＊）^2＋（△a^＊）^2＋（△b^＊）^2]^1/2。结果：随着体瓷厚度的增加,L^＊值显著下降（P〈0．05）,a^＊和b^＊值显著上升（P〈0．05）;随着烧结次数的增加,0．5mm厚度组和1．0厚度组L^＊值明显增大（P〈0．05）,而1．5mm厚度组未见明显差异;3组的a^＊值均明显减小（P〈0．05）,颜色向绿色偏移;1．0厚度组和1．5mm厚度组b^＊值明显增大（P〈0．05）,颜色向黄色偏移,而0．5mm厚度组b^＊值未见明显差异。不同体瓷厚度的△E值均〉3,而同一厚度下不同烧结次数后的两两比较,△E值均〈3。结论：Cercon氧化锆全瓷体瓷厚度增加后明度下降,色调趋向变红、变黄;随着烧结次数增加,明度增加,颜色向绿色、黄色偏移,但肉眼难以察觉。     

不同厚度及色调树脂与底色的混色效果分析

目的 研究不同厚度3种色调树脂试样与3种底色混色后颜色效果的变化。方法 选用A1、A3、C2色调树脂分别制成2．0、1．8、1．6、1．4、1．2、1．0mm试样5个。测色仪测定试样与3种底色材料混色后的L^＊8^＊b^＊值，分析色差。结果当厚度〉1．8mm时，试样在不同底色材料间的色差值aE’ab〈1；当厚度≤1．4mm时，部分试样在金属底色与两种树脂底色之间的色差值△E^＊ab〉2．72。结论 金属底色对试样表面的混色效果影响较大。使用树脂制作非金属冠修复体时，建议材料厚度应〉1．8mm。     

不同桩核材料对氧化铝全瓷冠颜色的影响

目的探讨4种不同桩核材料对氧化铝全瓷冠（In-Ceram）颜色的影响。方法选取1颗完整离体牙,进行截冠、完善根管治疗和桩道预备。制备不同材料的桩核预备体和1个氧化铝全瓷冠（In-Ceram）,分为4组（镍铬合金桩核组、金合金桩核组、氧化锆桩核组、纤维桩树脂核组）,每组10颗。采用Minolta CM-700d分光测色仪,测试4组不同桩核材料背景下氧化铝全瓷冠（InCeram）唇面中1/3区域的L^＊、a^＊、b^＊值,分别进行完全随机设计的单因素方差分析和两两比较的LED检验,并根据公式计算和比较色差△E。结果 4种不同的桩核材料背景下氧化铝全瓷冠（In-Ceram）的L^＊、a^＊、b^＊值的差异有统计学意义（FL=334.90,PL=0.000;Fa=4.43,Pa=0.009;Fb=359.22,Pb=0.000）。镍铬合金桩核和金合金桩核组的色差均超过临床可接受水平（△E〉2）;氧化锆桩核和纤维桩树脂核组的色差均不能为肉眼所识别（△E〈1.5）。结论临床应用氧化铝全瓷冠（In-Ceram）进行修复时,尤其在前牙区,不建议使用金属桩核。     

试色糊剂对Ips-empressⅡ全瓷冠颜色的影响

目的：观察试色糊剂对全瓷冠颜色的影响。方法：在临床上收集缺损、变色或过小的上前牙共计50颗,行全瓷冠修复（Ips-empressⅡ全瓷系统制作）。粘结前由同一实验人员用试色糊剂试色,将全瓷冠就位未涂试色糊剂时作为对照组,用电脑比色仪测定对照组及5种试色糊剂[A1、A3、Transluent（Trt）、Whiteopaque（WOT）和B0.5opaque（B0.5）]试色后的L、a、b值,用卡尺测量被测点的瓷层厚度,根据公式色ΔEab=（ΔL^2＋Δa^2＋Δb^2）1/2、Lab=L、Cab=（a^2＋b^2）^1/2、Hab=arctan（b/a）计算并分析每种糊剂试色后的色差、明度、饱和度和色相角。结果：50颗全瓷冠被测点（唇面中1/3）的平均瓷层厚度为1.668mm,用5种试色糊剂试色后的Lab、Cab、Hab值与对照组相比差异无显著性（P〉0.05）;5种试色糊剂引起的色差均小于1.5NBS,临床上肉眼均难以察觉。结论：当全瓷冠的瓷层厚度达到1.7mm时,粘结剂对修复体颜色的影响较小,肉眼难以察觉。随着瓷层厚度的下降,应考虑树脂粘结剂的遮色作用。     

温度变化对瓷贴面黏结剂颜色影响的实验研究

目的：研究温度变化对3种瓷贴面黏结剂颜色稳定性的影响。方法：用Vita T4透明瓷制作直径为10．0mm，厚为0．50mm的试件30个，随机分成A、B、C3组，A组采用EB化学固化黏结剂，B组采用RelyX Veneer光固化黏结剂，C组采用RelyX ARC双重固化黏结剂，均与玻璃底座黏结。然后用分光光度仪测境冷热循环前后的L^＊a^＊b^＊值，结果采用SPSS 10．0软件分析，比较3种黏结剂的颜色稳定性。结果：冷热循环前、后，A、B、C3组各自的L^＊a^＊b^＊值均有显著性差异（P〈0．05），平均△E值分别为3．10、1．41和1．43。与冷热循环前相比，3组的明度L^＊值均有显著降低，a^＊、b^＊值则有所增高。结论：EB化学固化黏结剂因颜色变化过于明显而不适宜做贴面黏结剂；RelyX veneer光固化黏结剂和RelyX ARC双重固化黏结剂虽然会发生一定的变色，但是基本能够满足临床美学要求。     

上颌中切牙冠修复体的口腔色差容忍度研究

目的：研究上中切牙冠修复体在口内环境下的色差容忍度（包括察觉度和接受度）,为提高配色技术成功率提供数据依据。方法：使用专业牙科比色仪器ShadepilotTM,测定66例单侧上颌中切牙冠修复体与对应天然牙的色差数据△E,以及各色度参数差△L＊、△C＊、△a＊、△b＊,根据每个患者在修复体戴入口腔后对其色差的主观感受,将病例分成三组：A组：不存在色差,效果满意;B组：存在色差,但效果满意;C组：存在色差,效果不满意。C组修复体在进行外部染色后再次进行色差测定,数据归入A组或B组,总色差与各参数色差分别进行统计分析,研究色差察觉度和接受度。结果：口腔环境中,上中切牙冠修复体色差察觉度约为1．6（△E单位）,色差接受度平均为4．06（△E单位）;当修复体的明度L＊及饱和度C＊高于天然牙时,其色差容忍度相对较高,而修复体明度L＊及饱和度低于天然牙时,色差容忍度较低;色调差异△a＊的存在对色差容忍度的影响均比较显著。结论：口腔修复体的色差容忍度,不仅与肉眼观察生理特征相关,与心理因素也有着一定的关系,若能充分了解人们对修复体色彩的审美倾向,将色差容忍度定量运用于比色技术中,将对提高修复体配色成功率十分有利。     

Optimization of Tooth Color and Shade Guide Design

PURPOSE: One critical prerequisite for dental shade guides is to match the color range and distribution of human teeth. The purpose of this study was to design computer models for dental shade guides and compare them with an existing shade guide. A targeted coverage error for a newly developed shade guide was DeltaE(ab) < 2 with a corresponding CIE2000 value. MATERIALS AND METHODS: A total of 1064 teeth were evaluated in vivo using an intra-oral spectrophotometer. Shade guide models were designed using different methods for representation of the data set, hierarchical clustering, and nonlinear constrained optimization. Coverage error was calculated for both CIELAB and CIE2000 values. Recorded values were compared with coverage error of Vitapan Classical (VC) shade guide. Wilcoxon signed-rank test for paired samples and linear regression were used in statistical analysis. RESULTS: Coverage error of VC was 4.1 (SD 1.8), ranging from 0.5 to 11.5 DeltaE(ab). Group A shades had the best match for human teeth (43.9%) followed by Groups C (24.1%), B (20.4%), and D (11.7%) shades, respectively. CIELAB coverage error of the newly designed 24-tab shade guide using clustering and optimization was 2.05 (0.95) and 1.96 (0.92), respectively. Corresponding CIE2000 coverage error values were 1.43 (0.68) and 1.40 (0.65), respectively. A significant difference between results obtained using clustering and optimization was determined. CIELAB color differences were greater, but highly correlated as compared with their CIE2000 counterparts (DeltaE(00)= 0.64 x DeltaE(76)+ 0.13, r > 0.99). DISCUSSION: This study demonstrated that, compared with existing shade guides, future shade guides can provide either (a) similar coverage of tooth color with fewer tabs, thus simplifying shade matching procedure, or (b) better coverage of tooth color with a similar number of tabs, in both cases increasing the chances of satisfactory matches and, consequently, better esthetics. CONCLUSIONS: Both clustering and optimization enabled better representation of tooth color as compared with an existing dental shade guide. Optimization outperformed clustering and is therefore recommended as a method of choice for representation of tooth color and designing of dental shade guides.     

金属烤瓷修复体色度学研究

目的：研究金属烤瓷修复体色度学特征，为临床金属烤瓷修复的比色、配色提供指导。方法：数码照像计算机色度分析系统分别测定1296件金属烤瓷修复体、792颗活体前牙和Vita比色板色片的色度，分析并比较金属烤瓷修复体、活体前牙和Vita比色板各色片色度值范围，金属烤瓷修复体与Vita比色板匹配情况及色度值差异情况。结果：金属烤瓷修复体、活体前牙和Vita比色板各色片色度值范围不吻合，金属烤瓷修复体的颜色主要分布在Vita比色板的个别色片，金属烤瓷修复体与Vita比色板的色度差为△L＊0．45，△a＊1．14，△b＊0．56，△E＊ab2．58。结论：金属烤瓷修复体的色度与Vita比色板色片相差较大。     

Correlations between Color Differences Based on Three Color-Difference Formulas Using Dental Shade Guide Tabs

Purpose: The purpose of this study was to determine the correlation among color-difference values based on three formulas between shade tab pairs from two shade guides [Vita Lumin (VITA) and Chromascop (CHRO)].
Materials and Methods: The color of shade tabs was measured relative to the standard illuminant D₆₅ under the 8° standard observer function, and distributions for CIE L *, a *, and b * values were compared. One hundred and twenty shade pairs from VITA and 190 shade pairs from CHRO were used to calculate color differences using CIELAB, DIN99, and CIEDE2000 formulas (Δ E*_ab , Δ E ₉₉, and Δ E ₀₀, respectively). A paired t- test was used to determine the difference between each pair of the three color-difference values (α= 0.01). Regression analysis was used to determine the correlations between the color differences (α= 0.01).
Results: For both shade guides, there were significant differences between Δ E*_ab and Δ E ₀₀, Δ E*_ab and Δ E ₉₉, and Δ E ₉₉ and Δ E ₀₀ ( p < 0.01). Δ E*_ab and Δ E ₀₀, and Δ E*_ab and Δ E ₉₉ were strongly correlated (r²= 0.90 to 0.94, p < 0.05). Although a simplified a * rescaling function of the CIE a * axis has been added in the CIEDE2000 formula, the influence of the opposite signs in the a * value were found to be irrelevant to the Δ E ₀₀ value.
Conclusion: Δ E*_ab, Δ E ₉₉, and Δ E ₀₀ can be used interchangeably for the evaluation of color difference of shade tabs.     

Comparison of CIE lab, CIEDE 2000, and DIN 99 color differences between various shades of resin composites

PURPOSE: In addition to the CIE Lab color-difference formula (deltaE*ab), advanced formulas that include weighting functions have been introduced. The objectives of this study were to determine the correlations in color differences between different shade pairs of resin composites by different color formulas, and to determine whether the weighting functions included in the advanced formulas influenced the color-difference values. MATERIALS AND METHODS: Color was measured after polymerization of two resin composites in 26 shades, and color differences between shades were calculated by deltaE*ab, CIEDE 2000 (deltaE00), and DIN 99 (deltaE99) formulas. Regression analyses were performed between the color differences calculated by three formulas in each group divided by the differences in color parametric factors between the pairs compared. RESULTS: There were significant correlations between deltaEab and deltaE00, deltaEab and deltaE99, and deltaE99 and deltaE00 (r2 = .99, .89, and .90, respectively). The weighting functions in the CIEDE 2000 formula had influence on deltaE00 values when differences in chroma and hue between compared pairs were great. CONCLUSION: Differences in parametric factors between the pairs compared influenced the correlation between deltaE*ab and deltaE99 values (r2 = .25 to .97). As the CIEDE 2000 formula has been proven to be better matched to observer responses and showed significant involvement of weighting functions compared to CIE Lab color difference, this formula should be considered for evaluation of the color of resin composites.     

氧化铝全瓷冠、镍铬合金烤瓷冠和天然牙之间色度差的比较研究

目的明确氧化铝全瓷冠、镍铬合金烤瓷冠以及天然牙三者之间的颜色差异。方法选择上前牙氧化铝烤瓷冠修复病例43例,用Vitapan classic比色板比色,同牙模型制作氧化铝烤瓷冠和镍铬合金烤瓷冠,用Crystaleye电脑比色仪分别读取氧化铝烤瓷冠,镍铬合金烤瓷冠和天然牙的颈,中,切三部的L*a*b*值,计算各部的色度差值。结果氧化铝烤瓷冠与天然牙在颈,中,切部的色度差值小于2.75,肉眼无明显的感知差。镍铬合金烤瓷冠与天然牙和氧化铝烤瓷冠在颈部和中部的色度差值大于2.75,肉眼有明显的感知差,切端的色度差值小于2.75。结论用Vitapan classic比色板比色条件下,镍铬合金烤瓷冠与天然牙切端相似,颈部和中部有明显的肉眼感知差。氧化铝烤瓷冠与天然牙的色度有比较高的相似性。     

Comparison of CIELAB DeltaE(*) and CIEDE2000 color-differences after polymerization and thermocycling of resin composites.

OBJECTIVES: Though instrumental technologies have been widely used for quantifying color of esthetic dental materials, the sizes for the perceptible or acceptable color-difference varied. Instead of the CIELAB DeltaE(*)(DeltaE(ab)(*)) formula, the CIEDE2000 (DeltaE(00)) formula that included weighting and parametric functions was introduced. The objective of this study was to determine the correlation between color-difference values of DeltaE(ab)(*) and DeltaE(00) after polymerization and thermocycling of dental resin composites. METHODS: Color-differences were calculated between unpolymerized and polymerized, and between polymerized and thermocycled resin composites. Color was measured relative to the standard illuminant D65 over a white background with SCE geometry. Regression analyses were performed between the color difference values of DeltaE(ab)(*) and DeltaE(00). RESULTS: There were significant correlations between DeltaE(ab)(*) values and DeltaE(00) values after polymerization and thermocycling (p<0.01), and the correlation coefficient was 0.99 and 0.98, respectively. SIGNIFICANCE: Within the limit of this study, the results suggest that two color-difference formulas can be used interchangeably for the evaluation of the color-difference of resin composites after polymerization and thermocycling. However, for the evaluation of changes in separate color parameters such as lightness, chroma and hue, the DeltaE(00) formula could be considered for the color evaluation of esthetic dental materials after confirming with human observer responses.     

应用分光光度仪比较深度变色基牙表面4种全瓷冠色度学特征

目的:采用分光光度比色仪评估深度变色ND8基底表面4种全瓷冠各部分色度学参数CIE L^*a^*b^*值及与目标色片色差。方法:制作ND8色基牙预备体,分别戴入Procera氧化铝、Procera氧化锆、Lava氧化锆、IPS E.max高度不透明压铸陶瓷底冠,分光光度仪对颈部、体部、切端测色。4组底冠经烧结A2体瓷后戴入基底(总瓷层厚度控制1.5 mm),分光光度仪同法测色,以Vitapan比色板A2体瓷色片为对照,对数据进行单因素方差分析、均数比较Bonferroni检验,计算P值。结果:4组底冠均提高基牙的L^*值,降低彩度a^*、b^*值,多数组间各部位L^*、a^*、b^*有统计学差异。烧结体瓷后,各组L^*略下降,a^*、b^*明显上升。各部分与A2色差显著减小(1.45∽3.70)。结论:4组全瓷底冠对变色基底都有较好遮色性,但各组底冠明度、彩度不一致。烧结体瓷后颜色有差异的组别减少,各组与目标色片差别在临床可接受范围。     

烧结次数对牙科全瓷微结构和色差的影响

目的：评价烧结次数对牙科全瓷微结构和色差的影响。方法：样本由3种品牌的全瓷材料制作,即：热压全瓷（IPS EmpressⅡ）、氧化铝全瓷（In-Cream alumina）和氧化锆全瓷（Cercon CAD/CAM zirconia）。通过X射线衍射仪（x-ray diffractomer,XRD）和扫描电子显微镜（scanning electron microscope,SEM）表征烧结后全瓷样本,分光光谱仪上测量和计算烧结后全瓷样本的色差（ΔE＊ab）。结果：XRD和SEM结果显示5次烧结后热压全瓷基底冠和饰面瓷均发生由无定形玻璃相向晶相的转变,而氧化铝全瓷和氧化锆全瓷的转变则相反。烧结次数与全瓷品牌和ΔE＊ab之间存在交互作用（P〈0.05）。氧化铝全瓷5次烧结后的色差最大（1.9）,已接近临床可接受色差的域值。结论：烧结次数因玻璃相与晶相之间的相互转变对色差造成影响,5次烧结后热压全瓷发生了玻璃相向晶相的转化,氧化锆全瓷几乎不受影响。但5次烧结后的3种全瓷的色差变化仍在视觉可接受范围内。     

Study of the variation between CIELAB delta E* and CIEDE2000 color-differences of resin composites

This study sought to assess the significance of the corrections introduced in the new CIEDE2000 color difference formula with respect to deltaE*ab. The purpose of which was to provide sounder knowledge, and hence more informed decision-making, about applying this new formula to dental resin composites. With two different hybrid composites, color differences were calculated between unpolymerized and polymerized resin composites, between polymerized resin composites of different thicknesses (1 and 2 mm), and between polymerized resin composites cured with halogen and LED light curing units (LCUs). The two formulas differed significantly, with VAB(E) (equal size) values higher than the inter-observer variability (VAB (E)=11%) and VAB(O) (original size) values greater than 25% for each of the data sets analyzed. Results obtained in this study agreed with and thus supported the recent recommendation of the Commission Internationale de l'Eclairage (CIE), whereby the new CIEDE2000 formula should be used to evaluate color differences of resin composites.