X-ray diffraction evidence for the presence of β(AgHg) in dental amalgam

Samples of (Ag + Hg) amalgam and of dental amalgam have been prepared and stored at temperatures of 23, 37.5, and 60°C for various lengths of time up to 10 years. X-ray diffraction and optical microscopy have been employed to determine the approximate increase in the β(AgHg) phase as a result of the γ β transition in the AgHg system. Data are presented to show that the transition occurs in both systems but much less rapidly in dental amalgam. Increases in storage temperature increase the rate of the transition in both systems.