Migration of metallic ions from screwposts into dentin and surrounding tissues

Previous investigations have shown htat corrosion and other electrochemical processes occure when different alloys or metals are found together in the same mouth. In the present report, when teeth were restored using non-noble metallic posts, the metals diffused out to surrounding hard and soft connective tissues. The material consisted of extracted teeth with screw posts and surrounding discolored connective tissues. The screwposts had been cemented to the teeth 3--10 years earlier. The distribution of metal ions was determined by means of energy-dispersive X-ray microanalysis. Copper and zinc were found in both hard and soft tissues. Relatively high concentrations of copper ions were identified in areas of the teeth with blue-green discolorations. Zinc ions were detected in the dentin; they most probably originated from the screwposts and the cement, but zinc is also found in normal human dentin. Copper, zinc, silver and iron were found in the dark discolorations of the gingiva adjacent to the extracted teeth.