Radioopacifier in Mineral Trioxide Aggregate-Synthesis and Solidification of Bi2o3/Zro2 Composite Powders

Bismuth oxide is a rare-earth metal oxide with the melting point at 824 oC. There are various polymorphic materials of bismuth oxide that can be used as the solid electrolyte and photo catalyst. Additionally, bismuth oxide is also a major constitute of mineral trioxide aggregate (MTA) and serves as the radio pacifier within MTA. The R&D trends of MTA mainly focus on its constitution, biocompatibility, physical and chemical properties, and its setting time, etc.. In the present proposal, we will investigate the feasibility of replacing bismuth oxide with zirconium or tantalum oxide without sacrificing its radiopacity. In the first year, mechanical milling of starting bismuth oxide and zirconium oxide powder will be proceed and followed by heat treatment to reveal a suitable composite composition. Wet bath methods such as sol-gel and co-precipitation process will be used to prepare composite powder and followed by calcinations to further improve the radiopacity of composite powder. In the second year, fine adjustment of composite powder will be continued. Meanwhile the optimum composite composition will be mixed with Portland cement to investigate its setting performance and mechanical properties after solidification. Biocompatibility of the optimum composition will be performed and confirmed in its practical application.