Abstract
In this study, reduction of the dental casting procedure time only 45 minutes after the start of the mixing was achieved by mixing with an accelerator solution.Three commercial quick-heating gypsum-bonded investments and H3PO4 and K2SO4 solutions were used.The following changes were observed using the accelerator:reduced fluidity, shorter setting time, and rapid increase of setting expansion and green strength.The optimal concentrations of H3PO4 and K2SO4 were 0.5mass% and 1.0mass%, respectively.The surface roughness of castings prepared with and without the accelerator solution was not significantly different.The accuracies of casting were improved or not changed using this accelerator.Thus, the new technique of mixing a quick-heating gypsum-bonded investment with the accelerator solution reduced dental casting procedure time.
