[Experimental studies of casting contraction of crowns and bridges made of various alloys based on nickel (NI-CR)].

The results are presented of experimental studies of casting contraction of metal crowns and bridges with an attempt at outlining of practical suggestions concerning the choice of materials and work technology with alloys based on nickel. Casting contraction was determined for the following alloys: Gisadent MCA, Gisadent NCS1, Mikrostom-1 and Wiron-88. The need for further studies on alloys based on nickel which may be used for preparation of permanent replacements as substitutes of precious metals is caused in Poland and all over the world by economic factors.