Passivity of Some Dental Materials in Ringer’s Solution

U ovome radu ispitana je korozijska otpornost dviju eksperimentalnih zubnih slitina, Co-Cr-Mo i Co-Cr-Ni, jedne komercijalne Co-Cr-Mo (Wironit®) slitine, titana i Ag-amalgama (Permite®) u Ringerovoj otopini. Na osnovi elektrokemijskih mjerenja određen je relevantni pokazatelj lokalne korozije - piting potencijal Epit, pri kojem nastaje proboj pasivnoga sloja i pojava lokalne korozije. Vrjednovanjem materijala prema piting potencijalu pokazalo se da je korozijski najstabilniji čist titan, slijede ga komercijalna slitina Wironit®, te Co Cr-Mo i Co-Cr-Ni slitine, a amalgam se je pokazao najmanje otpornim u ispitnim uvjetima koji oponašaju medij usne šupljine.In this paper corrosion resistance of two experimental dental alloys, Co-Cr-Mo and Co-Cr-Ni, one commercial Co-Cr-Mo (Wironit®) alloy, high purity titanium and Ag-amalgam (Permite®) was studied in Ringer’s solution. On the basis of electrochemical measurements, the relevant indicator of local corrosion - pitting potential Epitt , at which the breakdown of passive layer and the effects of local corrosion start, was determined. By ranking of materials according to pitting potential, it was found that pure titanium is the most stable material followed by commercial alloy Wironit®, Co-Cr-Mo and Co-Cr-Ni alloys, while amalgam showed the lowest resistance in the experimental conditions of model oral cavity medium