Colorimetric determination of gamma 2 phase in dental amalgam

A new quantitative colorimetric test for the gamma 2 phase of dental amalgam, developed by Kropp, has been used to examine a number of the newer "low gamma 2" dental amalgam alloys. The original method has been modified in that the wavelength at which the color was read was changed from 578 nm to 700 nm. Of the dental amalgams tested, Tytin and Caulk Ease had the lowest gamma 2 phase content after 24 hours. Kropp's colorimetric method for gamma 2 phase determination is simple, quick, and convenient and requires relatively simple equipment, namely a colorimeter. However, for general use, a more convenient quantitative reference standard needs to be developed.