Electrochemical characteristics of high-Pd alloys in relation to Pd-allergy.
Electrochemical characteristics of high-Pd alloys in relation to Pd-allergy.
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DOI：
10.1016/s0109-5641(00)00016-6
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发表时间：
2000-07
期刊：
影响因子：
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通讯作者：
D. W. Berzins;Isao Kawashima;R. Graves;N. Sarkar
中科院分区：
文献类型：
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作者：
D. W. Berzins;Isao Kawashima;R. Graves;N. Sarkar
目的研究pd - cu基牙科陶瓷合金是否具有与其他含pd合金不同的电化学特性。在所有含pd的合金中，这种特殊的合金组与过敏和超敏反应的频繁发生有关。电化学腐蚀可能引发这些反应。方法采用传统的腐蚀测量方法，在20°C的磷酸盐缓冲盐水溶液中对四组合金（Pd-Cu、Pd-Ga -（含和不含Ag）、Pd-Ag和Au-Pd）进行腐蚀测试。测定的电化学特性为：(1)20h开路电位（OCP）；(2) 20h腐蚀速率（Icorr）；(3)阳极极化E-i曲线。结果无银Pd-Ga和pd - cu基合金的OCP值（232±25 mV）均高于含银合金的OCP值（144±52 mV）。不同合金的icorr值，尽管成分不同，但彼此难以区分。所有合金的E-i曲线基本相似，含银（>5wt%）合金的阳极斜率在腐蚀电位以上100mV范围内存在细微差异。Pd- cu合金和无银Pd- ga合金的OCP值与纯Pd（239±21 mV）的OCP值相当，这表明在腐蚀过程中，这些合金发生了合金化，从而在其表面富集了Pd。这种条件有利于致敏性Pd++离子的释放，并为Pd - cu合金相关的超敏反应的频繁发生提供了合理的解释。其他合金的OCP值归因于脱合金，然后表面富集Ag和/或Au，并可能在各自的合金表面形成不溶的AgCl表面膜。这些事件有可能抑制或阻止Pd++离子的释放。具有这些特征的合金很少与过敏反应联系在一起。
ObjectiveThe aim of this study was to determine whether the Pd–Cu-based dental ceramic alloys possess any electrochemical characteristics distinguishable from that of other Pd-containing alloys. Of all Pd-containing alloys, this particular alloy group has been linked to frequent incidence of allergy and hypersensitivity reactions. Electrochemical corrosion may instigate these reactions.MethodsFour groups of alloys, Pd–Cu, Pd–Ga-(with and without Ag), Pd–Ag, and Au–Pd, were evaluated by traditional corrosion measurement techniques in a phosphated buffer saline solution at 20°C. The electrochemical characteristics measured were: (1) 20h open circuit potential (OCP); (2) 20h corrosion rate (Icorr); and (3) anodic polarization (E–i) curves.ResultsThe OCP values (232±25 mV ) of the Ag-free Pd–Ga and Pd–Cu-based alloys were higher than and distinctly different from that (144±52 mV ) of the Ag-containing alloys. The Icorrvalues of different alloys, despite varied compositions, were indistinguishable from one another. The E–i curves of all alloys were essentially similar, with the Ag-containing (>5wt%) alloys showing a subtle difference in their anodic slope within 100mV above their corrosion potentials.SignificanceThe OCP values of Pd–Cu alloys and the Ag-free Pd–Ga alloy are comparable to that reported for pure Pd (239±21 mV ), which indicates that during corrosion these alloys undergo dealloying and consequent Pd-enrichment on their surface. Such a condition is conducive to the release of allergenic Pd++ions and offers a plausible explanation for the frequent incidence of hypersensitivity reactions associated with the Pd–Cu alloys. The OCP values in other alloys are attributed to dealloying followed by surface enrichment with Ag and/or Au and the possible formation of an insoluble AgCl surface film on the respective alloy surfaces. These events have the potential to suppress or prevent Pd++ion release. Alloys showing these characteristics have seldom been linked to allergic reactions.