The tensile creep characteristics of dental amalgam. I. Stress dependence.

Equipment is described which enables the determination of the creep behavior of small specimens of dental amalgam under tensile stresses. The apparatus has been used to measure the creep strain of both low and high copper dental amalgams at 34 degrees C, in the stress range 9.4 to 38.8 MNm(-2), for time periods of up to 24 h. Significant differences were found in the controlling creep mechanisms for the various amalgam types. Conventional amalgam displayed classical steady-state creep. The high copper amalgams, however, were best represented by transient creep equations implying interference to the motion of dislocations by the presence of hardening precipitates.