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首页> 外文期刊>The Journal of Prosthetic Dentistry >Mechanical properties, fracture surface characterization, and microstructural analysis of six noble dental casting alloys.
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Mechanical properties, fracture surface characterization, and microstructural analysis of six noble dental casting alloys.

机译：六种贵金属牙科铸造合金的力学性能，断裂表面表征和微观结构分析。

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STATEMENT OF PROBLEM: Because noble dental casting alloys for metal ceramic restorations have a wide range of mechanical properties, knowledge of these properties is needed for rational alloy selection in different clinical situations where cast metal restorations are indicated. PURPOSE: The purpose of this study was to compare the mechanical properties and examine both the fracture and polished surfaces of 6 noble casting alloys that span many currently marketed systems. Five alloys were designed for metal ceramic restorations, and a sixth Type GPT has Type IV alloy for fixed prosthodontics (Maxigold KF) was included for comparison. MATERIAL AND METHODS: Specimens (n=6) meeting dimensional requirements for ISO Standards 9693 and 8891 were loaded to failure in tension using a universal testing machine at a crosshead speed of 2 mm/min. Values of 0.1% and 0.2% yield strength, ultimate tensile strength, elastic modulus, and percentage elongation were obtained. Statistical comparisons of the alloy mechanical properties were made using 1-way ANOVA and the REGW multiple-range test (alpha=.05). Following fracture surface characterization using scanning electron microscopy (SEM), specimens were embedded in epoxy resin, polished, and again, examined with the SEM. RESULTS: When the multiple comparisons were considered, there were generally no significant differences in the elastic modulus, 0.1% and 0.2% offset yield strength, and ultimate tensile strength for the d.SIGN 91 (Au-Pd), d.SIGN 59 (Pd-Ag), Capricorn 15 (Pd-Ag-Au) and Maxigold KF (Au-Ag-Pd) alloys, except that the ultimate tensile strength was significantly lower (P<.05) for Maxigold KF than these other 3 alloys. These 4 mechanical properties were generally significantly lower (P<.05) for Aquarius XH (Au-Pt-Pd) and Brite Gold XH (Au-Pt). The d.SIGN 59 (14.6%) and Capricorn 15 (13.8%) alloys had the highest values of mean percentage elongation, which were not significantly different. Aquarius XH (6.0%) and Maxigold KF (4.2%) had the lower mean values of percentage elongation, which were also not significantly different. The polished and etched surfaces for all alloys revealed equiaxed, fine-grain microstructures, and all fracture surfaces contained casting porosity. Incomplete solidification suggestive of dendritic structures was observed for some alloys. Fracture surfaces were complex, with characteristic features of both brittle and ductile fracture. Precipitate particles on the fracture surfaces indicated the multi-phase character of the alloys. CONCLUSIONS: For the important mechanical property of yield strength, there were generally no significant differences among the Au-Pd, Pd-Ag, Pd-Ag-Au and Au-Ag-Pd alloys. Wide variation was found in percentage elongation, with the Pd-Ag and Pd-Ag-Au alloys having the highest values and the Au-Pd-Pt and Au-Ag-Pd alloys having the lowest values.
机译：问题陈述：由于用于金属陶瓷修复体的贵金属牙科铸造合金具有广泛的机械性能，因此需要这些适应性知识，以便在需要临床指示铸造金属修复体的不同临床情况下进行合理的合金选择。目的：本研究的目的是比较机械性能，并检查跨越许多当前市售系统的6种贵金属铸造合金的断裂和抛光表面。为进行比较，设计了五种合金用于金属陶瓷修复体，第六种GPT具有固定修复牙齿的IV型合金（Maxigold KF）。材料和方法：使用万能试验机以2 mm / min的十字头速度将符合ISO标准9693和8891尺寸要求的试样（n = 6）加载至拉伸失效。获得了0.1％和0.2％的屈服强度，极限抗拉强度，弹性模量和伸长百分比的值。使用1向ANOVA和REGW多范围测试（alpha = .05）对合金的力学性能进行统计比较。使用扫描电子显微镜（SEM）表征断裂表面后，将样品包埋在环氧树脂中，进行抛光，然后再次用SEM检查。结果：当考虑多重比较时，d.SIGN 91（Au-Pd），d.SIGN 59（d.SIGN 91（Au-Pd））的弹性模量，0.1％和0.2％的偏移屈服强度以及极限拉伸强度通常没有显着差异。 （Pd-Ag），摩Cap座15（Pd-Ag-Au）和Maxigold KF（Au-Ag-Pd）合金，但Maxigold KF的极限抗拉强度明显低于其他三种合金（P <.05）。对于Aquarius XH（Au-Pt-Pd）和Brite Gold XH（Au-Pt），这4种机械性能通常明显较低（P <.05）。 d.SIGN 59（14.6％）和摩ri座15（13.8％）合金的平均伸长率百分比值最高，差异不显着。 Aquarius XH（6.0％）和Maxigold KF（4.2％）的百分比伸长率平均值较低，也没有显着差异。所有合金的抛光和蚀刻表面均显示出等轴细晶粒组织，所有断裂表面均具有铸件孔隙。对于某些合金，观察到不完全凝固提示树突结构。断裂表面复杂，具有脆性和延性断裂的特征。断裂表面上的沉淀颗粒表明了合金的多相特征。结论：对于重要的屈服强度力学性能，Au-Pd，Pd-Ag，Pd-Ag-Au和Au-Ag-Pd合金之间通常没有显着差异。发现百分伸长率变化很大，Pd-Ag和Pd-Ag-Au合金的值最高，而Au-Pd-Pt和Au-Ag-Pd合金的值最低。

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