Objective

To determine the Weibull modulus $m$, the characteristic strength ${\sigma }_0$,the subcritical crack growth (SCG) parameters ($n$ & $A^{*}$) as well as the lifetime durability of three dental ceramic materials in water: a polycrystalline yttria-stabilized zirconia (Zenostar MT O, YSZ, Ivoclar Vivadent/Wieland, Germany), a lithium disilicate glass ceramic (IPS e.max CAD, LD, Ivoclar Vivadent, Liechtenstein), and a zirconia-containing lithium silicate glass ceramic (Celtra Duo, ZLS, Dentsply Sirona Inc, USA).

Methods

30 specimens (Ø12 mm × 0.9 mm thickness) of each material were fabricated. The biaxial ring-on-ring bending tests at four stress rates $\dot{\sigma }$ (100, 10, 1, 0.1 MPa/s) were performed in water for all three ceramics. The results were used to determine the Weibull and SCG parameters, and to plot the Strength-Probability-Time (SPT) diagram.

Results

YSZ showed the highest $m$ (12.5) and highest ${\sigma }_0$ (542 MPa), while the values for the glass ceramic materials were lower: for LD $m$ = 4.7, ${\sigma }_0$ = 407 MPa, and for ZLS $m$ = 2.7, ${\sigma }_0$ = 279 MPa. The $n$ for YSZ, LD and ZLS in water were 31.1, 13.7 and 16.6, respectively. The strength of YSZ decreased by 50% within a simulated period of 10 years, and for the glass ceramic materials the decrease was up to 80%.

Significance

Determining the Weibull and SCG parameters from the constant stress rate testing is an efficient methodology for ranking materials in terms of durability and longevity.

中文翻译：

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牙科陶瓷材料的强度表征和寿命预测

目的

确定威布尔模量 $米$，特性强度 ${\sigma }_0$，亚临界裂纹扩展（SCG）参数（$ñ$ 和 ${\mathrm{一种}}^{*}$）以及三种牙科陶瓷材料在水中的使用寿命：多晶氧化钇稳定的氧化锆（Zenostar MT O，YSZ，伊沃克拉尔·瓦瓦登特/威兰德，德国），二硅酸锂玻璃陶瓷（IPS e.max CAD，LD， Ivoclar Vivadent，列支敦士登）和含氧化锆的硅酸锂玻璃陶瓷（Celtra Duo，ZLS，Dentsply Sirona Inc，美国）。

方法

每种材料制作了30个样品（Ø12mm×0.9 mm厚度）。双轴环在四个应力率下的弯曲测试$\dot{\sigma }$对于所有三种陶瓷，均在水中进行了（100、10、1、0.1 MPa / s）测试。结果用于确定Weibull和SCG参数，并绘制强度-概率-时间（SPT）图。

结果

YSZ显示最高 $米$ （12.5）和最高 ${\sigma }_0$ （542 MPa），而玻璃陶瓷材料的值较低：对于LD $米$ = 4.7， ${\sigma }_0$ = 407 MPa，对于ZLS $米$ = 2.7， ${\sigma }_0$= 279兆帕。的$ñ$水中的YSZ，LD和ZLS分别为31.1、13.7和16.6。在10年的模拟时间内，YSZ的强度降低了50％，而玻璃陶瓷材料的强度降低了80％。

意义

通过恒定应力率测试确定Weibull和SCG参数是一种根据耐久性和寿命对材料进行排名的有效方法。