van Vuuren L Jansen, Odendaal J S J, Pistorius P C
Department of Dental Sciences, Faculty Health Sciences, Tshwane University of Technology, Private Bag X680, 0001 Preoria.
SADJ. 2008 Feb;63(1):034-8.
When two or more metals or alloys are placed in contact with one another inside the oral cavity, galvanic coupling may occur which may lead to galvanic corrosion. Galvanic corrosion may release elements from the alloy into the oral cavity with possible harm to the patient. This in vitro study was conducted to determine the extent of galvanic corrosion where different dental amalgams and Co-Cr alloy combinations were placed in contact with artificial saliva as an electrolyte. The tests were conducted with potential measurements as well as potentiodynamic and potentio-static polarisation techniques. Results showed that the galvanic corrosion current density is much lower than the corrosion current density, indicating that galvanic coupling of the samples does not have a substantial effect on the overall corrosion of the samples. The corrosion potential differences between three of the four couples were above the minimum 50 mV potential difference, which is considered a potential harmful level, with only the Wironium Plus and Dispersalloy combination being under 50 mV potential difference. It is concluded that: Galvanic corrosion does not pose a greater threat to the alloys than ordinary corrosion. A Wironium Plus and Dispersalloy combination may be the safest where a Co-Cr and amalgam combination is required in the mouth of a patient.
当两种或更多种金属或合金在口腔内相互接触时，可能会发生电偶耦合，这可能导致电偶腐蚀。电偶腐蚀可能会使合金中的元素释放到口腔中，对患者造成潜在危害。本体外研究旨在确定不同牙科汞合金与钴铬合金组合作为电解质与人工唾液接触时的电偶腐蚀程度。测试采用电位测量以及动电位和恒电位极化技术进行。结果表明，电偶腐蚀电流密度远低于腐蚀电流密度，这表明样品的电偶耦合对样品的整体腐蚀没有实质性影响。四组配对中的三组之间的腐蚀电位差高于50 mV的最小电位差，这被认为是潜在的有害水平，只有Wironium Plus和Dispersalloy组合的电位差低于50 mV。得出的结论是：电偶腐蚀对合金造成的威胁并不比普通腐蚀更大。在患者口腔中需要钴铬合金与汞合金组合的情况下，Wironium Plus和Dispersalloy组合可能是最安全的。
