Corrosion of galvanic pairs of dental alloys copper base with silver amalgams in artificial saliva

ABSTRACT Galvanic corrosion is a metal dissolution process that occurs when two metals of different electrochemical potential are immersed in an electrolyte causing electrical currents between the metals through the conducting medium. To restore lost or damaged teeth, different alloys are used, leaving the mouth exposed to electrical currents that circulate through saliva and dental fluids. In the present work, the potentials and densities of corrosion currents of galvanic pairs of silver amalgams and copper base dental alloys were determined simultaneously using potenciodynamic methods, finding that the most resistant to corrosion are the pairs formed by silver amalgams of high copper and Cu -Zn alloys, and that the corrosion products released in greater quantity in the electrolytic medium are formed by Hg, Cu, Zn and Ni ions.【摘要】电偶腐蚀（Galvanic corrosion）是指当两种电化学电位不同的金属浸入电解质中时，会通过导电介质在金属间形成电流，进而引发的金属溶解过程。为修复缺失或受损的牙齿，临床会使用多种牙科合金，这使得口腔处于唾液与牙科体液可传导电流的环境中。本研究通过动电位法（potenciodynamic methods）同步测定了银汞合金（silver amalgams）与铜基牙科合金（copper base dental alloys）构成的电偶对的电位及腐蚀电流密度，结果显示：由高铜银汞合金与铜锌（Cu-Zn）合金构成的电偶对抗腐蚀性能最优，且在电解质介质中释放量最高的腐蚀产物为汞（Hg）、铜（Cu）、锌（Zn）与镍（Ni）离子。