DENTAL IMPRESSION MATERIALS BASED ON RUBBER AND GLASS COMPOSITION IN MgO-CaO-Al2O3-SiO2 QUATERNARY SYSTEM

摘要

PURPOSE: A glass composition in the MgO-CaO-Al2O3-SiO2 quaternary system is provided for use as a filler for dental impression materials. The glass has much improved mechanical strength and viscosity compared with the conventional ternary glass composition. CONSTITUTION: The quaternary glass composition, MgO-CaO-Al2O3-SiO2, is prepared by the following steps of: preparing a batch by mixing 20wt.% of Al2O3, 50wt.% of SiO2, and 30wt.% of MgO and CaO, wherein the weight ratio of MgO to CaO is 0.2-2, and drying mixtures; melting the batch at 1650deg.C; quenching the molten batch; grinding; repeating the process of melting and quenching; and optionally thermal treating the ground batch at annealing point and cooling slowly for removing stress. The dental impression materials with low viscosity(light body) contain 25-35wt.% of prepared quaternary glass filler.