Study of the possible galvanic corrosion of several prosthetic alloys coupled with their usual post-solder in an artificial saliva

摘要

The frameworks supporting ceramics in dental prostheses are constituted of main parts of a same alloy which are joined together by soldering. Since it is always possible that a surface part of the parent alloy and the postsoldered joint can be together exposed to the buccal milieu, a galvanic coupling phenomenon may occur between the two. Indeed, they always display different electrochemical properties, which can lead to an exchange current between the two in contact with saliva. A possible consequence, in case of galvanic corrosion, should be a weakening of the framework which can cause a too early rupture of the prosthesis. Galvanic coupling experiments were performed over three days in an artificial saliva especially prepared according to the Afnor norm. Corrosion potentials and polarization resistances were recorded. The measured values were analyzed by taking into account the E-pH diagrams of the different elements belonging to the parent alloy and the post-solder alloy.