Department of Metallurgy and Materials Engineering, Faculty of Engineering, University of Malta, Malta.
Dent Mater. 2011 Sep;27(9):879-91. doi: 10.1016/j.dental.2011.04.012. Epub 2011 May 14.
Investigation of the replacement of bismuth oxide by zirconium oxide in mineral trioxide aggregate (MTA) and characterization and evaluation of the radiopacity and physical properties of varying replacements of zirconium oxide mixed at either water-powder or water-cement proportions of 0.3. The suitable filler loading of zirconium oxide for Portland cement in a MTA system for use as a root-end filling material was thus determined.
Portland cement replaced by zirconium oxide in varying amounts ranging from 0% to 50% in increments of 10 was mixed with water either at a water/powder (WP) proportion or at a water/cement (WC) proportion of 0.3. Portland cement and ProRoot MTA were used as controls. The materials' microstructures were investigated using optical light microscopy. The radiopacity, strength, setting time, water uptake, solubility, sorption and porosity of the specimens were also evaluated. The optimum formulation was selected using the digital logic method.
Portland cement replaced with 30% zirconium oxide mixed at a water/cement proportion of 0.3 resulted to have the optimum combination of properties. This material exhibited radiopacity, compressive strength, setting time, water uptake, solubility and sorption comparable to ProRoot MTA. Both microscopy and the evaluation of porosity from the solubility and sorption experiments indicated a degree of porosity consisting mainly of capillary pores and entrapped air voids.
A filler loading of 30% zirconium oxide to Portland cement mixed at a water to cement proportion of 0.3 resulted in a material with comparable properties to mineral trioxide aggregate.
研究在三氧化物聚合体（MTA）中用氧化锆替代氧化铋，并对不同氧化锆替代比例（水-粉比例或水-水泥比例为 0.3）的 MTA 的射线可透性和物理性能进行表征和评估。从而确定作为根尖封闭材料的 MTA 系统中氧化锆在波特兰水泥中的合适填料负载量。
以 10%为增量，将氧化锆以 0%至 50%的不同比例替代波特兰水泥，与水混合，水-粉（WP）比例或水-水泥（WC）比例为 0.3。以波特兰水泥和 ProRoot MTA 作为对照。使用光学显微镜研究材料的微观结构。还评估了试件的射线可透性、强度、凝固时间、吸水率、溶解度、吸附和孔隙率。使用数字逻辑方法选择最佳配方。
以 30%氧化锆替代的波特兰水泥，在水-水泥比例为 0.3 时，具有最佳的性能组合。这种材料的射线可透性、抗压强度、凝固时间、吸水率、溶解度和吸附性与 ProRoot MTA 相当。显微镜检查和从溶解度和吸附实验评估的孔隙率表明，存在一定程度的孔隙率，主要由毛细孔和被困的空气空隙组成。
在水-水泥比例为 0.3 的条件下，将 30%的氧化锆作为波特兰水泥的填料，得到的材料与三氧化物聚合体具有相当的性能。
