Enhancement of a titanium denture frame model: mold temperature and spruing factors.

This study evaluated the sensitivity of an experimental model to mold temperature using a two-chamber casting machine and its recommended investment (Exp. 1), and the effect of sprue diameter and length using a one-chamber casting machine and its recommended investment (Exp. 2). Experimental patterns were cast from commercially pure titanium and percentage casting success obtained. Mold temperatures of 620, 350 and less than 100 degrees C, and sprues, 4 or 6 mm diameter and 5, 20 or 26 mm long, were used. The effect on casting success of a "non-system" investment was also evaluated in both experiments. The experimental model did not discriminate the two lower mold temperatures (Exp. 1). Casting success was significantly lower with a 4 mm sprue diameter but was not affected by sprue length (Exp. 2). The results suggest the importance of the combination of casting machine, investment type and mold dimension.