Bona Alvaro Della, Anusavice Kenneth J, DeHoff Paul H
School of Dentistry, The University of Passo Fundo, P.O. Box 611/613, Passo Fundo, RS 99001-970, Brazil.
Dent Mater. 2003 Nov;19(7):662-9. doi: 10.1016/s0109-5641(03)00010-1.
To test the hypothesis that the Weibull moduli of single- and multilayer ceramics are controlled primarily by the structural reliability of the core ceramic.Methods. Seven groups of 20 bar specimens (25 x 4 x 1.2 mm) were made from the following materials: (1) IPS Empress--a hot-pressed (HP) leucite-based core ceramic; (2) IPS Empress2--a HP lithia-based core ceramic; (3 and 7) Evision--a HP lithia-based core ceramic (ES); (4) IPS Empress2 body--a glass veneer; (5) ES (1.1 mm thick) plus a glaze layer (0.1 mm); and (6) ES (0.8 mm thick) plus veneer (0.3 mm) and glaze (0.1 mm). Each specimen was subjected to four-point flexure loading at a cross-head speed of 0.5 mm/min while immersed in distilled water at 37 degrees C, except for Group 7 that was tested in a dry environment. Failure loads were recorded and the fracture surfaces were examined using SEM. ANOVA and Duncan's multiple range test were used for statistical analysis.
No significant differences were found between the mean flexural strength values of Groups 2, 3, 5, and 6 or between Groups 1 and 4 (p>0.05). However, significant differences were found for dry (Group 7) and wet (Groups 1-6) conditions. Glazing had no significant effect on the flexural strength or Weibull modulus. The strength and Weibull modulus of the ES ceramic were similar to those of Groups 5 and 6.
The structural reliability of veneered core ceramic is controlled primarily by that of the core ceramic.
验证关于单层和多层陶瓷的威布尔模量主要由核心陶瓷的结构可靠性控制这一假设。方法。用以下材料制作了七组每组20个条形试样（25×4×1.2毫米）：（1）IPS Empress——一种热压（HP）白榴石基核心陶瓷；（2）IPS Empress2——一种热压氧化锂基核心陶瓷；（3和7）Evision——一种热压氧化锂基核心陶瓷（ES）；（4）IPS Empress2瓷体——一种玻璃贴面；（5）ES（1.1毫米厚）加一层釉（0.1毫米）；（6）ES（0.8毫米厚）加贴面（0.3毫米）和釉（0.1毫米）。除第7组在干燥环境中测试外，每个试样在37℃的蒸馏水中以0.5毫米/分钟的十字头速度进行四点弯曲加载。记录破坏载荷，并使用扫描电子显微镜检查断裂表面。采用方差分析和邓肯多重极差检验进行统计分析。结果：第2、3、5和6组的平均抗弯强度值之间或第1和4组之间未发现显著差异（p>0.05）。然而，在干燥（第7组）和潮湿（第1 - 6组）条件下发现了显著差异。上釉对抗弯强度或威布尔模量没有显著影响。ES陶瓷的强度和威布尔模量与第5和6组相似。意义：贴面核心陶瓷的结构可靠性主要由核心陶瓷的结构可靠性控制。
