Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336 Munich, Germany.
Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336 Munich, Germany.
Dent Mater. 2019 Oct;35(10):1439-1449. doi: 10.1016/j.dental.2019.07.020. Epub 2019 Aug 7.
To test the impact of zirconia pretreatment and aging on flexural strength and phase structure.
For flexural strength measurements, 180 3Y-TZP specimens were fabricated and pretreated: (i) air-abraded (105-μm alumina, 0.25MPa), (ii) air-abraded (50-μm alumina, 0.25MPa), (iii) air-abraded (30-μm silica-coated alumina, 0.28MPa) (iv) non-pretreated. Each pretreated group (n=15) was aged: (a) hydrothermal (134°C, 0.23MPa, 2h) (b) in a mastication simulator (1,200,000×, 5/55°C) and (c) not aged. The fractured specimens were stored dry for 5 years (23°C) for analysis of phase transformation. Additionally, specimens were fabricated from 3Y-TZP (n=12) and 3Y-TZP (n=8), pretreated (i, ii, iii, iv), and hydrothermally aged. Each air-abrasion method was alternated using 0.05, 0.25 and 0.4MPa pressure. The phase transformation was examined by Raman spectroscopy and surface topography by scanning electron microscope. Data were analyzed using univariate ANOVA with the Scheffé post hoc test and partial-eta-squared (ƞ²) (α=0.05).
The highest impact on flexural strength was exerted by the pretreatment (η²=0.261, p<0.001), followed by interactions between pretreatment and aging (η²=0.077, p=0.033). Non-pretreated and non-aged specimens showed the lowest monoclinic percentage. Hydrothermal aging and 5 years of storage at room temperature increased the monolithic percentage of 3Y-TZP. The highest phase transformation was observed in groups air-abraded with 105-μm alumina particles. Increasing pressure during the air-abrading process increased the content of the monoclinic phase in zirconia surfaces.
Air-abrasion with 30-μm silica-coated alumina powder can be recommended for pretreatment of 3Y-TZP and 3Y-TZP. For air-abrasion using alumina powder lower pressure should be used.
测试氧化锆预处理和老化对弯曲强度和相结构的影响。
为了进行弯曲强度测量，制备了 180 个 3Y-TZP 样本，并进行了预处理：（i）空气喷砂（105μm 氧化铝，0.25MPa），（ii）空气喷砂（50μm 氧化铝，0.25MPa），（iii）空气喷砂（30μm 硅烷涂层氧化铝，0.28MPa），（iv）未预处理。每个预处理组（n=15）都进行了老化处理：（a）湿热（134°C，0.23MPa，2h），（b）在咀嚼模拟器中（1,200,000×，5/55°C），（c）未老化。将断裂的样本在 23°C 下干燥储存 5 年（23°C），以分析相变。此外，还从 3Y-TZP（n=12）和 3Y-TZP（n=8）制备样本，进行预处理（i、ii、iii、iv）和湿热老化。每种空气喷砂方法都使用 0.05、0.25 和 0.4MPa 的压力交替进行。通过拉曼光谱检查相变，通过扫描电子显微镜检查表面形貌。使用单变量方差分析和 Scheffé 事后检验以及偏 eta 平方（ƞ²）（α=0.05）进行数据分析。
预处理对弯曲强度的影响最大（η²=0.261，p<0.001），其次是预处理和老化之间的相互作用（η²=0.077，p=0.033）。未预处理和未老化的样本显示出最低的单斜百分比。湿热老化和室温下储存 5 年增加了 3Y-TZP 的整体单斜百分比。使用 105μm 氧化铝颗粒进行空气喷砂的组观察到最高的相转变。在空气喷砂过程中增加压力会增加氧化锆表面的单斜相含量。
可以推荐使用 30μm 硅烷涂层氧化铝粉末进行 3Y-TZP 和 3Y-TZP 的预处理。对于使用氧化铝粉末进行空气喷砂，应使用较低的压力。
