Ha William Nguyen, Kahler Bill, Walsh Laurence James
School of Dentistry, The University of Queensland, Oral Health CenterHerstonQueenslandAustralia.
Acta Biomater Odontol Scand. 2016 Oct 5;2(1):130-137. doi: 10.1080/23337931.2016.1239181. eCollection 2016 Dec.
To assess the effects on curing conditions (dry versus submerged curing) and particle size on the compressive strength (CS) and flexural strength (FS) of set MTA cement. Two different Portland cements were created, P1 and P2, with P1 < P2 in particle size. These were then used to create two experimental MTA products, M1 and M2, with M1 < M2 in particle size. Particle size analysis was performed according to ISO 13320. The particle size at the 90th percentile (i.e. the larger particles) was P1: 15.2 μm, P2: 29.1 μm, M1: 16.5 μm, and M2: 37.1 μm. M2 was cured exposed to air, or submerged in fluids of pH 5.0, 7.2 (PBS), or 7.5 for 1 week. CS and FS of the set cement were determined using a modified ISO 9917-1 and ISO 4049 methods, respectively. P1, P2, M1 and M2 were cured in PBS at physiological pH (7.2) and likewise tested for CS and FS. Curing under dry conditions gave a significantly lower CS than when cured in PBS. There was a trend for lower FS for dry versus wet curing. However, this did not reach statistical significance. Cements with smaller particle sizes showed greater CS and FS at 1 day than those with larger particle sizes. However, this advantage was lost over the following 1-3 weeks. : Experiments that test the properties of MTA should cure the MTA under wet conditions and at physiological pH.
评估固化条件（干燥固化与浸没固化）和粒度对凝固型MTA水泥抗压强度（CS）和抗折强度（FS）的影响。制备了两种不同的波特兰水泥，P1和P2，P1的粒度小于P2。然后用它们制备了两种实验性MTA产品，M1和M2，M1的粒度小于M2。根据ISO 13320进行粒度分析。第90百分位数处的粒度（即较大颗粒）为P1：15.2μm，P2：29.1μm，M1：16.5μm，M2：37.1μm。M2在空气中固化，或浸没在pH值为5.0、7.2（PBS）或7.5的液体中1周。分别使用改良的ISO 9917-1和ISO 4049方法测定凝固水泥的CS和FS。P1、P2、M1和M2在生理pH值（7.2）的PBS中固化，并同样测试CS和FS。干燥条件下固化的CS明显低于在PBS中固化时的CS。干燥固化与潮湿固化相比，FS有降低的趋势。然而，这未达到统计学显著性。粒度较小的水泥在第1天时的CS和FS比粒度较大的水泥更高。然而，在接下来的1-3周内这种优势消失了。：测试MTA性能的实验应在潮湿条件和生理pH值下固化MTA。
