Experimental and FE shear-bonding strength at core/veneer interfaces in bilayered ceramics
Experimental and FE shear-bonding strength at core/veneer interfaces in bilayered ceramics
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DOI：
10.1016/j.dental.2011.03.001
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发表时间：
2011-06-01
期刊：
影响因子：
5
通讯作者：
Watts, David C.
中科院分区：
文献类型：
--
作者：
Ereifej, Nadia;Rodrigues, Flavia Pires;Watts, David C.
目标。采用剪切强度试验和有限元分析（FEA）的方法比较陶瓷贴面材料与两种不同陶瓷芯材的粘结强度。用IPS e.max ZirCAD (Ivoclar-Vivadent, Schaan, Liechtenstein) （ZirCAD）和二硅酸锂IPS e.max CAD （LS）各制作15块陶瓷芯。根据制造商的说明，使用IPS e.max Ceram（Ceram）贴面。然后将样品安装，放置在剪切测试夹具中，并使用通用试验机在其芯/贴面界面加载。然后在45x下对断裂标本进行断口学检查。采用独立t检验和Mann-Whitney U检验分别检测两组间粘结强度和失效模式的差异（p < 0.05）。建立了二维平面应力有限元模型，并模拟了试验条件下的剪切加载。平均剪切应力（MPa）为：ZirCAD/Ceram为28.8 (9.5)，LS/Ceram为29.1（8.3）。差异无统计学意义。两组之间的断裂模式有显著差异，所有的ZirCAD/Ceram样品在其界面处都有粘结性断裂，而LS/Ceram样品在贴面或核心处都有粘结性断裂或混合粘结/粘结性断裂。FEA模型中的应力分布也不同，这与两组不同的断裂模式相对应。虽然剪切应力相似，但断口分析和有限元模拟表明，贴面陶瓷与玻璃陶瓷之间的结合优于与氧化锆岩心之间的结合。改善粘接技术是防止临床氧化锆单板修复体脱层的必要条件。(C) 2011年牙科材料学会。Elsevier Ltd.出版。版权所有。
Objectives. To compare the bond strength of a ceramic veneer material to two different ceramic core materials using shear strength testing and finite element analysis (FEA).Methods. 15 blocks of ceramic cores were made of each of IPS e.max ZirCAD (Ivoclar-Vivadent, Schaan, Liechtenstein) (ZirCAD) and lithium disilicate IPS e.max CAD (LS). These were veneered using IPS e.max Ceram(Ceram) according to the manufacturers' instructions. Samples were then mounted, placed inside a shear testing jig and loaded at their core/veneer interfaces with a universal testing machine. Fractured specimens were then examined fractographically at 45x. An independent t-test and a Mann-Whitney U test were used to detect differences in bond strengths and the patterns of failure between the two groups, respectively (p > 0.05). Two-dimensional plane stress FE-models were constructed and subjected to shear loading simulating the experimental conditions.Results. Mean shear stresses (MPa) were 28.8 (9.5) for ZirCAD/Ceram and 29.1 (8.3) for LS/Ceram. Differences were not statistically significant. Fracture patterns were significantly different between the 2 groups as all ZirCAD/Ceram samples broke adhesively at their interface while LS/Ceram samples broke cohesively in the veneer or the core or had mixed adhesive/cohesive failure. Stress distributions in the FEA models were also different, corresponding to the variable fracture patterns in the 2 groups.Significance. Although shear stresses were similar, fractographic analysis and finite element modeling suggested better bonding between the veneering ceramic and the glass-ceramic than to the zirconia cores. Improved bonding techniques are necessary to prevent clinical delamination of veneered zirconia restorations. (C) 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.