Analyses of the amalgam-tooth interface using the electron microprobe.

The electron microprobe was used to study tooth discoloration caused by old silver amalgam fillings. Oscilloscopic displays were obtained for the distribution of tin, silver, and mercury. In addition, a linear graphic display technic on the Enhancitron was used. The oscilloscopic displays showed the migration of tin from the amalgam into the enamel and dentin as opposed to silver or mercury, or both. These findings confirm that tooth discoloration is due to the presence of tin from the process of corrosion rather than from mercury.