Viennot Stéphane, Lissac Michèle, Malquarti Guillaume, Dalard Francis, Grosgogeat Brigitte
Department of Prosthodontics, Laboratoire d'Etude des Interfaces et des Biofilms en Odontologie (EA 637), Faculty of Odontology, University of Claude Bernard Lyon I, Rue Guillaume Paradin, 69372 Lyon Cedex 08, France.
Acta Biomater. 2006 May;2(3):321-30. doi: 10.1016/j.actbio.2006.01.001. Epub 2006 Mar 22.
The aim of this study was to compare the in vitro corrosion resistance in artificial saliva of two palladium-silver alloys (a Pd-Ag (Pors on 4) and an Ag-Pd (Palliag LTG)), with and without casting defects; 1 nickel-chrome alloy and 1 high-gold alloy, cast under recommended conditions, served as controls. For each of the palladium-based alloys, three specimens corresponding to three different casting conditions were used: under recommended conditions, with the use of a graphite-containing investment and crucible, and by reusing the sprues and sprue button. The electrochemical tests were run in Fusayama-Meyer artificial saliva. The open-circuit potential was recorded in mV/SCE at t=24h. Then, potentiodynamic polarization was performed to measure the polarization resistance (R(p)) in kOmega cm(2) and the corrosion current (i(corr)) in microA cm(-2). Data were evaluated with one-way analysis of variance and multiple comparisons test (alpha=0.05). In addition, each specimen was examined by scanning electron microscopy. Compared to the control alloys, the electrochemical experiments in artificial saliva indicated satisfactory corrosion resistance for the Pd-Ag and Ag-Pd alloys; these results are related to their high noble metal content and stable substructure. The Pd-Ag alloy displayed superior electrochemical properties to those of the Ag-Pd alloy regardless of the casting condition. The use of the graphite-containing crucible and investment during the cast process did not dramatically reduce the corrosion resistance values, but the reuse of sprues and the sprue button did. The optimal corrosion resistance values were obtained for the alloys cast according to the recommended conditions.
本研究的目的是比较两种钯银合金（一种钯银合金（Pors on 4）和一种银钯合金（Palliag LTG））在有无铸造缺陷情况下在人工唾液中的体外耐腐蚀性；1种镍铬合金和1种高金合金在推荐条件下铸造，用作对照。对于每种钯基合金，使用对应三种不同铸造条件的三个试样：在推荐条件下、使用含石墨的包埋料和坩埚以及重复使用浇道和浇口棒。电化学测试在舟山市迈耶人工唾液中进行。在t = 24小时时以mV/SCE记录开路电位。然后，进行动电位极化以测量极化电阻（R(p)）（单位为kΩ cm²）和腐蚀电流（i(corr)）（单位为μA cm⁻²）。数据采用单因素方差分析和多重比较检验进行评估（α = 0.05）。此外，每个试样通过扫描电子显微镜检查。与对照合金相比，在人工唾液中的电化学实验表明钯银合金和银钯合金具有令人满意的耐腐蚀性；这些结果与其高贵金属含量和稳定的亚结构有关。无论铸造条件如何，钯银合金都比银钯合金表现出更好的电化学性能。在铸造过程中使用含石墨的坩埚和包埋料并没有显著降低耐腐蚀性值，但重复使用浇道和浇口棒则会降低。按照推荐条件铸造的合金获得了最佳的耐腐蚀性值。
