Passivity Study of Dental Ni-Cr-Mo Alloys in Fluorides Media
J.W.J. Silva, N.A.S. Sampaio, H.A. Acciari, R.Z. Nakazato, E.N.Codaro

Abstract
A large number of metal alloys is used in dentistry to manufacture fixed and removable prostheses. In oral cavity these structures are exposed to a chemically adverse environment, with saliva being the most corrosive agent due to the high concentration of chloride ions that are causing localized corrosion. Another important factor is pH, which can vary from 2 to 11, depending on the food ingested. One of the most important factors determining the use of an alloy for making prosthesis is its corrosion resistance. The tests were performed with the Ni-Cr-Mo alloys, commercially called Nichrom, Wiron 99 and Superbond in a buffer HF/NaF, pH between 4.5 and 5.0 at a temperature of about 37° C, simulating an oral environment. The obtained data suggest that the alloy Nichrom has a higher corrosion resistance when compared to the other two under the same conditions.

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