Sadeq Abdulaziz, Cai Zhuo, Woody Ronald D, Miller Amp W
Department of Restorative Sciences, Baylor College of Dentistry, Texas A&M University System Health Science Center, Dallas, Texas, USA.
J Prosthet Dent. 2003 Jul;90(1):10-7. doi: 10.1016/s0022-3913(03)00263-4.
Titanium-ceramic bonding is less optimal than conventional metal-ceramic bonding, due to excessive oxidation of titanium during porcelain firing.
This in vitro study evaluated the effects of porcelain firing atmosphere and gold sputter coating on titanium surfaces on porcelain bonding to machined and as-cast titanium substrates. Material and methods Eight groups of ASTM grade 2 commercially pure (CP) titanium specimens (13 mm x13 mm x1 mm) were prepared (n=10). A conventional Au-Pd-In metal-ceramic alloy (Orion) and an ultra low-fusing porcelain (Finesse) served as the control (n=10). Forty machined titanium specimens were prepared from 1.00-mm thick titanium sheets with a diamond band saw. Forty titanium specimens were produced in a centrifugal dental titanium casting machine. All titanium specimens were airborne particle abraded with 110-microm alumina particles, whereas the control specimens were airborne particle abraded with 50-microm alumina particles. Forty titanium specimens (20 specimens each of as-cast and machined titanium) were randomly selected for gold sputter coating before ceramic firing. An ultra low-fusing porcelain (Vita Titankeramik) was fused on the central 6-mm diameter circular area on each titanium specimen. Porcelain firing environments for the titanium specimens consisted of vacuum and a reduced argon atmosphere. Porcelain was debonded by a biaxial flexure, constant strain test at a cross-head speed of 0.25 mm/min. Specimens were analyzed by standardized SEM/EDS analysis 3 times throughout the study to determine the silicon atomic percentage (Si at %): (1) after airborne particle abrasion, before porcelain application; (2) after the application of the first layer of porcelain; and (3) after the fracture of porcelain from the metal substrate. The titanium-ceramic adhesion was characterized by determining the area fraction of adherent porcelain (AFAP). Results were analyzed by analysis of variance and the Student-Newman-Keuls test (alpha=.05).
Statistical analysis showed a significant difference in the AFAP values among all the groups. AFAP value of the control group was significantly higher (135.35 +/- 23.68) than those of the experimental groups (P<.001). For the machined titanium, AFAP value of gold sputter-coated/argon group (91.38 +/- 7.93) was significantly higher than the rest of the groups (P<.001). For the as-cast titanium fired in vacuum, significantly lower AFAP values (P<.001) were found in the gold sputter-coated group (50.2 +/- 11.26 vs 66.15 +/- 10.41). AFAP values between the argon groups with or without the gold coating were not significantly different (P=.303); however, both argon groups (93.83 +/- 4.65 and 98.09 +/- 6.35) showed significantly higher AFAP values compared with the vacuum groups (P<.001).
Firing porcelain in a reduced argon atmosphere significantly improved titanium-ceramic bonding for machined and as-cast titanium. The sputter-coated gold layer on titanium provided improved titanium-ceramic bonding only when combined with firing porcelain in reduced argon atmosphere. When porcelain was fired in vacuum in the presence of the gold layer, the titanium-ceramic bonding was weakened in as-cast titanium and was not affected in machined titanium. Conventional noble metal-ceramic bonding was superior to titanium-ceramic bonding regardless of the interfacial variables examined in this study.
由于在烤瓷过程中钛过度氧化，钛 - 陶瓷结合不如传统的金属 - 陶瓷结合理想。
本体外研究评估了烤瓷气氛和钛表面金溅射涂层对烤瓷与加工态及铸造态钛基底结合的影响。材料与方法制备八组ASTM 2级商业纯（CP）钛试件（13mm×13mm×1mm）（n = 10）。一种传统的金 - 钯 - 铟金属陶瓷合金（Orion）和一种超低熔烤瓷（Finesse）用作对照（n = 10）。用金刚石带锯从1.00mm厚的钛板制备40个加工态钛试件。在离心式牙科钛铸造机中制备40个钛试件。所有钛试件均用110微米氧化铝颗粒进行空气颗粒研磨，而对照试件用50微米氧化铝颗粒进行空气颗粒研磨。在烤瓷前，随机选择40个钛试件（加工态和铸造态钛各20个）进行金溅射涂层处理。在每个钛试件中心直径6mm的圆形区域熔覆一种超低熔烤瓷（Vita Titankeramik）。钛试件的烤瓷环境包括真空和还原氩气氛。通过双轴弯曲、以0.25mm/min的十字头速度进行恒应变试验使烤瓷脱粘。在整个研究过程中，通过标准化的扫描电子显微镜/能谱分析（SEM/EDS）对试件进行3次分析，以确定硅原子百分比（Si at%）：（1）空气颗粒研磨后、烤瓷应用前；（2）第一层烤瓷应用后；（3）烤瓷从金属基底断裂后。通过确定附着烤瓷的面积分数（AFAP）来表征钛 - 陶瓷附着力。结果通过方差分析和Student - Newman - Keuls检验进行分析（α = 0.05）。
统计分析表明所有组的AFAP值存在显著差异。对照组的AFAP值（135.35±23.68）显著高于实验组（P < 0.001）。对于加工态钛，金溅射涂层/氩气组的AFAP值（91.38±7.93）显著高于其他组（P < 0.001）。对于在真空中烧制的铸造态钛，金溅射涂层组的AFAP值显著更低（P < 0.001）（50.2±11.26对66.15±10.41）。有或没有金涂层的氩气组之间的AFAP值无显著差异（P = 0.303）；然而，与真空组相比，两个氩气组（93.83±4.65和98.09±6.35）的AFAP值均显著更高（P < 0.001）。
在还原氩气氛中烧制烤瓷显著改善了加工态和铸造态钛的钛 - 陶瓷结合。钛表面的溅射涂层金层仅在与在还原氩气氛中烧制烤瓷相结合时才改善钛 - 陶瓷结合。当在有金层的情况下在真空中烧制烤瓷时，铸造态钛的钛 - 陶瓷结合减弱，而加工态钛不受影响。无论本研究中所考察的界面变量如何，传统贵金属 - 陶瓷结合均优于钛 - 陶瓷结合。
