【作者】 裴延平；

【导师】 陈吉华；

【作者基本信息】 第四军医大学 ， 口腔临床医学， 2004， 硕士

【摘要】 金-瓷修复体(Porcelain-fused-to-metal PFM)，具有强度高、制作工艺简单、耐磨性好、色泽稳定及形态逼真等优点，自20世纪50年代问世以来，深受牙科医生及患者的欢迎。因此，尽管其尚存在一些有待改进的地方，但仍是目前最为普遍的固定修复方式。 色彩是评价金-瓷修复体质量的重要指标之一。金-瓷修复体的成败关键之一是其颜色能否有效仿真，使修复体与天然牙达到一致的视觉效果。临床上修复体色彩方面的失败，主要是由于遮色瓷未能有效地遮盖底层帽状冠金属色；或遮色瓷太厚造成体瓷厚度不足以遮盖遮色瓷颜色而引起色偏差。遮色瓷位于金属基底与体瓷之间，其主要功能在于遮盖底层的金属色并显出修复体颜色的基调，与体瓷层、釉瓷层共同构成修复体颜色。遮色瓷和体瓷层的最佳厚度会因所选择的颜色、所采用的金-瓷系统的不同而有差异。 适合性是衡量固定修复体临床效果及修复质量的重要指标之一，反映了修复体整体就位的完全程度和边缘密合度。适合性是一个广义的概念，包括铸造精度，通常指牙预备体与修复体之间间隙的大小，也就是粘固剂层的厚度。适合性不良的修复体将导致菌斑聚集，进而发生继发龋、龈缘炎，严重影响牙体、牙周组织健康及修复体颈缘的美观效果。在评价适合性的众多指标中，第四军医大学硕士学位论文较被公认的是Mcl ean和Van Fraunhofer的研究结果:边缘浮出量的最大临床接受值是120阳。 关于不同金属基底对烤瓷修复体色彩及边缘适合性的对比研究目前还没有一个系统客观的评价，对以电沉积金为基底瓷修复体的遮色瓷和体瓷厚度对修复体色彩的影响目前也还未见报道。本文旨在比较不同金属基底、不同遮色瓷和体瓷厚度对金瓷修复体色彩的影响，探讨不同金属基底对瓷修复体边缘适合性的影响，为临床提供一定的理论依据和指导。 本实验使用CR一321色差仪测量试件，用C工E1976一L*a*b*色度系统来表示色彩差异。对相同金属基底不同遮色瓷厚度组，以及不同金属基底相同遮色瓷厚度组之间的△E分别进行分析，且与临床结果进行对照，找出能有效遮住金属底色的最佳遮色瓷厚度值;在一定的遮色瓷厚度下，对相同金属基底不同体瓷瓷层厚度组以及不同基底相同体瓷厚度组之间的△E分别进行分析，比较不同金属基底不同体瓷厚度对修复体的色彩影响;采用硅橡胶填充修复体与基牙代型之间的间隙，通过立式光学计测量硅橡胶的厚度来比较不同金属基底烤瓷冠上瓷前后的适合性，扫描电镜下测量三种基底烤瓷冠粘固后的边缘浮出量并进行比较;对不同基底修复体在不同过程不同部位的浮出量进行多因素方差分析。根据实验结果可得出如下结论: 1.遮色瓷厚度与其遮色能力呈非线形正比关系，即厚度增加，遮色能力增加，但厚度达一定值后，色差值不再增加。 2.肉眼观察以镍铬合金与贵金属合金为基底的瓷修复体，遮色瓷厚度达到0.3mm时可以完全遮住底色，但与遮色瓷厚度为o.Zmm的色差值小于1 .SNBS，提示对镍铬合金和贵金属合金，遮色瓷厚度达到o.Zmm以后，肉眼不易分辨其色彩差异;以金沉积为基底的瓷修复体，遮色瓷厚度为0.lmm时即可完全遮住底色，与遮色瓷厚度为0.2mm的色差值小于1 .5 NBS，因而提示o.lmm 第四军医大学硕士学位论文是金沉积为基底的修复体的最佳遮色瓷厚度，与临床结果基本一致。 3.遮色瓷厚度相同时，以贵金属为基底的修复体明度值略小于以镍铬合金为基底的修复体，以金沉积为基底的修复体明度值最大。 4.体瓷厚度相同时，金沉积瓷修复体颜色较贵金属与镍铬合.金瓷修复体颜色偏黄、偏红。 5.随体瓷厚度增加，金瓷修复体明度和彩度值呈下降趋势，颜色由黄红色向蓝绿色发展，以镍铬合金为基底的修复体明度值高于贵金属或金沉积金为基底的修复体。 6.对于相同金属基底的瓷修复体，当体瓷厚度达到1.lmm之后再增加其厚度，统计学分析无显著性差异(P>0.05)，色差值AE的绝对值小于1.SNBS，均在临床可接受范围内。 7.以贵金属合金和金沉积为基底的瓷修复体整体适合性无显著性差异(P>0.05)，均与镍铬合金为基底的瓷修复体整体适合性有显著性差异(P<0.05)。具体表现为:唇侧肩台，金沉积烤瓷冠适合性最好，与贵金属及镍铬合金烤瓷冠有显著性差异(P<0 .05):舌侧肩台三者无显著性差异(P>0.05);唇面中央，贵金属与金沉积烤瓷冠适合性优于镍铬合金;舌面中央，金沉积与贵金属烤瓷冠优于镍铬合金烤瓷冠，有显著性差异(P<0.05);切端，贵金属烤瓷冠适合性最好。 8.对三种瓷修复体在三个过程的适合性分别进行横向比较，金沉积与镍铬合金为基底的修复体均有显著性差异(P<0.05);对于相同金属基底的瓷修复体，上瓷前后适合性比较三者均无显著性差异(P>0.05)，但粘固前后比较均有显著性差异(P<仓。5)。 综上所述，以金沉积与贵金属合金为基底的烤瓷冠在色彩和边缘适合性方面均优于以镍铬合金为基底的瓷修复体。更多还原

【Abstract】 PFM dental restorations have been attractive to both dentist and patients because of their advantages since 1950s, such as good wear resistance, color stability, improved esthetics, higher mechanical strength, more simplified fabrication procedures and so on. PFM is still one of the most widespread methods for fixed restorations although it needs to be improve.Color measurement is one of the most important quality criteria for PFM. One of the key to the success of PFM is making the color simulate effectively, so that we cannot even differ restorations from the adjacent natural teeth at a glance. Generally speaking, there are two main factors contributing to the failures of PFM correlating with color. One is that the color of metal coping is not successfully masked. The other is that the thickness of dentin isn’t enough to mask out the color of opaque resulting in incorrect shade match. Opaque porcelain situates between metal coping and body porcelain, whose objective is to mask out the metal, provide the basic shade of the restoration, and aid in shade match together with body porcelain and vitreous enamel. The optimal thickness of opaque porcelain and body porcelain will be changed according to the color and ceramic used.Adaptation is an important quality criterion for fixed restorations, It reflects the precision and the seating conditions of restorations. Adaptation is a broad concept, includes casting precision, usually refers to the marginal gap between the tissue surface of restoration and abutment, or the thickness of cement after cementation. Unreliable marginal adaptation will result in accumulation of dental plaques, furthermore lead to secondary caries and marginal gingivitis. It will influence negatively not only the health of teeth and periodontal tissues, but also esthetic effects of gingival margins of restorations. Mclean and Van Fraunhofer have found that the maximum clinically acceptable marginal gap is 120 m, which has been used widely as a standard of marginal adaptation.There is no objective evaluation about the type of metal ceramic alloys on color and marginal adaptation, Among the published studies on the color of PFM, there is few about galvanoceramic restorations. This study was aimed to evaluate the effects that different metal copings and different porcelain thickness have on the colors of restorations, and to compare the marginal adaptation of restorations using different metal copings. We hope it can bring some clinical significance and be help in clinical practice.The colors of different PFM restorations was measured according to the CIE1976- L*a*b* color scale by a Minolta chromatics meter CR-321. The color difference (AE) was calculated and then analyzed. The optimal thickness of opaque porcelains on different metal copings was found and investigated the influence that different metal copings and different thickness of body porcelain have on the colors of restorations. Filled in the gap betweenrestorations and dies with silicone rubber. By measuring the thickness of silicone rubber, we compared the marginal adaptation of PFM before and after porcelain application. The marginal differences of PFM after cementation were measured by SEM and data were analyzed by multivariate ANOVA. The main findings of this study were as follows:1. The thickness of opaque porcelain is not linear with its masking ability, that is, the masking ability can be improved by the increase of thickness. But after the thickness reach a certain value, the color difference will no longer increase.2. As in the PFM whose coping made of Ni-Cr alloy or precious alloy, when the thickness of opaque porcelain arrives at 0.3mm, the color of metal coping can be successfully masked and it has no significant difference with those whose opaque porcelain arrive at o.2mm, It is suggested that when the thickness of opaque arrives at 0.2mm, the color difference cannot be distinguished by naked eyes. As to those made by galvanized forming, the minimum thickness of opaque porcelain is 0.1mm and AE i更多还原