Dental alloys are used for direct fillings, inlays, onlays, crown and bridges and because of these, their normal biting function and aesthetics can prevail. The aesthetic aspect, as the corrosion and mechanical properties are directly influenced by the agressivity of the corrosion media, which in this case is saliva. This type of bio-fluid is very complex because the oral cavity is an open cavity and the chemical composition and pH change more or