Abstract:

Objective   The purpose of this study was to investigate the influence of cryogenic treatment and age-hardening heat treatment on the micro-Vicker’s hardness of palladium-silver dental alloys. Methods     A low-gold content dental casting alloy composed of Ag-Pd-Cu-Au was prepared for this study. Experimental specimens according to standard requirements were prepared following a standard dental laboratory casting procedure, cast specimens were heated to 900 ℃ and quenched in ice water. The specimens were then divided into 4 groups. They were subsequently subjected to different treatments, including age-hardening heat treatment, cryogenic treatment, heat treatment combined with cryogenic treatment. The non-treated group was used as control. The micro-Vicker’s hardness value was examined. The significance of correlation was analyzed. Results   The micro-Vicker’s hardness of specimens after age-hardening heat treatment, cryogenic treatment, heat treatment combined with cryogenic treatment increased by 129%, 13% and 141%, respectively, compared with that of the non-treated control group. Conclusion   Age-hardening heat treatment and cryogenic treatment were effective in elevating the hardness of Ag-Pd-Cu-Au alloy.

Key words: dental casting alloy, age-hardening, cryogenic treatment, microhardness