Assessment of the Activity of Galvanic Couples Involving Amalgam Filling Materials

Abstract

Comparative studies of the corrosion and electrochemical properties of amalgam filling materials based on copper, silver and non-gamma-2 "Oralloy" amalgam (Switzerland) were carried out in aqueous solutions of sodium chloride, sodium bicarbonate and citric acid at room temperatures and under conditions of mechanical depassivation of the surface. Although copper amalgam is corrosion-resistant in control environments due to the formation of protective passivating layers on the surface, the test results show that the advantage of silver amalgam in all tested solutions is obvious. It has been confirmed that the “Oralloy” filling material has advantages over copper and silver amalgams in the corrosion-electrochemical aspect. It is corrosion resistant in physiological neutral and slightly alkaline solutions, like silver amalgam, but surpasses it in electrochemical inertness. It has been shown that when predicting the intensity of galvanic processes that occur in the presence of two or more dissimilar metallic inclusions in the oral cavity, the potential difference between them is a necessary but insufficient criterion. When deciding the compatibility of new filling materials and previously used ones, it is necessary to take into account the pH of the environment, the potential difference between them, their nature and surface condition, as well as their position on the surface of the teeth. If there is a possibility of abrasion of the amalgam surface by antagonist teeth, then the likelihood of galvanosis increases significantly.