Effect of time at 37 degrees C on the creep and metallurgical characteristics of amalgam.

When aged at 37 degrees C for six months, dental amalgam exhibits a marked decrease in the property of creep. The objective of this study was to investigate the relationship between this decrease in creep and selected metallurgical characteristics. The formation of beta 1 (Ag-Hg), the grain size of gamma 1 (Ag-Hg), and the composition of gamma 1 were chosen for investigation. Creep was determined according to ADA Specification test No. 1, beta 1 was measured by x-ray diffraction, and gamma 1 grain size and gamma 1 composition were determined by electron-probe microanalysis. The results showed that the decrease in creep was related to beta 1 formation and not to changes in either gamma 1 grain size or gamma 1 composition.