Della Bona Alvaro, Mecholsky John J, Anusavice Kenneth J
School of Dentistry, The University of Passo Fundo, P.O. Box 611/613, Passo Fundo, RS 99001 970, Brazil.
Dent Mater. 2004 Dec;20(10):956-62. doi: 10.1016/j.dental.2004.02.004.
This study was designed to characterize the fracture behavior of ceramics and test the hypothesis that variation in strength is associated with a variation in fracture toughness.
The following four groups of 20 bar specimens (25 x 4 x 1.2 mm) were fabricated (ISO standard 6872): E1, a hot-pressed leucite-based core ceramic (IPS Empress); E2, a hot-pressed lithia-based core ceramic (IPS Empress 2); ES, a hot-pressed lithia-based core ceramic (Experimental); and GV, a glass veneer (IPS Empress2 body). Specimens were subjected to four-point flexure loading in 37 degrees C distilled water. Fractographic analysis was performed to determine the fracture origin (c) for calculation of fracture toughness (KIC). Weibull analysis of flexure strength (sigma) data was also performed.
Differences in mean sigma and KIC were statistically significant for E1 and GV (p<0.05). These differences are associated with processing effects and composition.
The higher mean sigma and KIC values of E2 and ES core ceramics suggest potentially improved structural performance compared with E1 although the Weibull moduli of E1 and E2 are the same.
本研究旨在表征陶瓷的断裂行为，并检验强度变化与断裂韧性变化相关的假设。
制作了以下四组每组20个条形试样（25×4×1.2毫米）（ISO标准6872）：E1，一种热压白榴石基核陶瓷（IPS Empress）；E2，一种热压氧化锂基核陶瓷（IPS Empress 2）；ES，一种热压氧化锂基核陶瓷（实验用）；以及GV，一种玻璃贴面（IPS Empress2坯体）。试样在37℃蒸馏水中进行四点弯曲加载。进行断口分析以确定断裂起源（c），用于计算断裂韧性（KIC）。还对弯曲强度（σ）数据进行了威布尔分析。
E1和GV的平均σ和KIC差异具有统计学意义（p<0.05）。这些差异与加工效应和成分有关。
E2和ES核陶瓷较高的平均σ和KIC值表明，与E1相比，其结构性能可能有所改善，尽管E1和E2的威布尔模量相同。
