WHAT CAUSES THE CORROSION (RUSTING)?
Amalgam, like most other metals, when exposed to moisture and oxygen will rust or oxidize. When your miniature battery starts generating electrical current, the process of corroding (i.e. breakdown) of amalgam fillings is increased. This increases both the amount of mercury vapor and abraded particles that can be released into the oral cavity. There is scientific evidence that in addition to amplifying the corrosion problem, some individuals are very susceptible to these internal electrical currents. From your standpoint as a patient, the important thing to know is that dissimilar metals in the mouth can contribute to electrical activity and corrosion and that in some individuals this can cause unexplained pain, ulcerations, inflammation, etc. Another aspect of this overall problem is that electrolytic corrosion can be enhanced by gold and mercury fillings being in contact. So, if there is a mercury filling under a gold crown or if a gold filling or crown is in contact with an opposing
Metals tend to rust when they are exposed to an electrolyte like the atmospheric moisture. Rusting is caused by the chemical reaction of the metal surface and the oxygen present in the air and form the respective metal oxide on the surface. When a metal is kept indoors, moisture above about 65% relative humidity is required to rust iron. At higher humidity level contamination of pollutants will accelerate further rusting of the underlying metal.
