Weber Katia R, Meneghetti Daniel E, Benetti Paula, Della Bona Alvaro, Griggs Jason A, Borba Márcia
PhD student, Post-Graduation Program in Dentistry, Dental School, University of Passo Fundo (UPF), Passo Fundo, RS, Brazil.
Predoctoral student, Dental School, University of Passo Fundo (UPF), Passo Fundo, RS, Brazil.
J Prosthet Dent. 2023 Jun;129(6):931-937. doi: 10.1016/j.prosdent.2021.08.001. Epub 2021 Sep 3.
The lack of standardization regarding the loading piston material used in fatigue tests could limit the interpretation of study findings.
The purpose of this in vitro study was to evaluate the effect of the piston material on the fatigue behavior of a lithium disilicate glass-ceramic.
Plate-shaped, 1.2-mm-thick, lithium disilicate glass-ceramic specimens were cemented onto a dentin analog substrate with resin cement. The specimens were divided into 4 groups according to the piston material used in the fatigue test (n=30): metal, glass fiber-reinforced epoxy resin, ceramic, and human tooth. The fatigue test was performed in a mechanical cycling machine by using the boundary technique at 2 Hz in distilled water at 37 °C. The fatigue data were analyzed by using the Weibull distribution and a lifetime-inverse power law relationship. Failures were evaluated with fractography and transillumination.
The Weibull modulus (β) was similar among groups. The exponent of crack growth (n) was significantly greater for glass fiber-reinforced epoxy resin and tooth groups than for metal and ceramic; therefore, the probability of failure (P) of glass-ceramic specimens loaded by resin and tooth pistons depended more on load amplitude. Specimens tested with tooth showed the highest value of K (characteristic lifetime), which is an indication of greater survival. Radial crack was the only failure mode observed for all experimental groups.
The piston material influenced the fatigue survival of the lithium disilicate glass-ceramic. The glass fiber-reinforced epoxy resin piston closely simulated the fatigue behavior induced by the human tooth on the evaluated glass-ceramic.
疲劳试验中所用加载活塞材料缺乏标准化可能会限制对研究结果的解读。
本体外研究的目的是评估活塞材料对二硅酸锂玻璃陶瓷疲劳行为的影响。
将1.2毫米厚的板状二硅酸锂玻璃陶瓷标本用树脂粘结剂粘结到牙本质模拟基底上。根据疲劳试验中使用的活塞材料将标本分为4组（n = 30）：金属、玻璃纤维增强环氧树脂、陶瓷和人牙。在机械循环试验机中，于37°C蒸馏水中采用边界技术以2Hz进行疲劳试验。使用威布尔分布和寿命-逆幂律关系对疲劳数据进行分析。通过断口分析和透照法评估失效情况。
各组的威布尔模量（β）相似。玻璃纤维增强环氧树脂组和牙组的裂纹扩展指数（n）显著大于金属组和陶瓷组；因此，由树脂和牙活塞加载的玻璃陶瓷标本的失效概率（P）更多地取决于载荷幅值。用人牙测试的标本显示出最高的K值（特征寿命），这表明其存活率更高。所有实验组均观察到径向裂纹是唯一的失效模式。
活塞材料影响了二硅酸锂玻璃陶瓷的疲劳存活率。玻璃纤维增强环氧树脂活塞密切模拟了人牙对所评估玻璃陶瓷诱导的疲劳行为。
