Effect of a two-step ringless investment technique on alloy castability

An evaluation of the effects of a two-step ringless partial denture investment technique on the castability of a base metal crown and fixed partial denture alloy was made. Castability values were obtained for 60 test patterns cast on two different casting units at two different mold temperatures. No significant differences were found between the control technique and the experimental technique. However, significant differences were found between castings made by the two different casting units at a temperature of 1250 degrees F.