Department of Prosthodontics, Section of Dentistry, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
Dent Mater. 2011 Dec;27(12):1252-8. doi: 10.1016/j.dental.2011.09.002. Epub 2011 Oct 4.
Surface conditions are of interest in all-ceramic restorations since they can control both bonding and strength. Tensile testing methods are commonly used to evaluate surface conditions of ceramics. This work evaluated tensile properties of a feldspathic ceramic as-finished, sandblasted and etched under three stressing conditions: (1) biaxial flexure; (2) monotonic mastication loading, dry; and, (3) cyclic mastication loading, wet.
Feldspathic CAD/CAM blocks were sliced into Tabs 1mm thick, n=135 specimens were divided into 3 groups assigned to as-finished (600 grit SiC; control), sandblasted, and etched. Of the 45 specimens per group, 35 specimens were used for bonded tests and 10 specimens for biaxial flexure testing. Pin-on-three ball biaxial testing was performed per ISO 6872. 35 specimens were bonded to dentin-analog bases and loaded to radial crack pop-in beneath a 3mm diameter piston. 20 specimens were tested dry with failure determined by acoustic emission methods. 15 specimens, bonded to bases having micro-channels for water transport, were cyclically loaded beneath the 3mm piston under water at 15Hz for 500,000 cycles.
Biaxial flexure distinguished among all three surface conditions (p<0.05, ANOVA). Monotonic testing could not distinguish among groups. Cyclic testing could not distinguish between sandblasted and etched groups but both were weaker than as-finished.
Mastication loading of bonded specimens creates a different stress state than simple flexure due to contributions of the cement-ceramic interface. Water adds a damage accumulation effect. Tensile stress conditions need to be chosen with the desired outcomes considered.
表面状况在全瓷修复体中很重要，因为它可以控制结合和强度。拉伸测试方法常用于评估陶瓷的表面状况。本工作评估了长石陶瓷的拉伸性能，其表面状态分别为抛光、喷砂和酸蚀，在三种受力状态下进行测试：（1）双向弯曲；（2）干态咀嚼加载；（3）湿态循环咀嚼加载。
长石 CAD/CAM 块切成 1mm 厚的薄片，n=135 个试件分为 3 组，分别为抛光（600 目 SiC；对照组）、喷砂和酸蚀。每组 45 个试件中，35 个试件用于粘结测试，10 个试件用于双向弯曲测试。按照 ISO 6872 进行三点弯曲测试。35 个试件粘结到牙本质模拟基底上，用直径 3mm 的活塞加载至径向裂纹弹出。20 个试件在干燥状态下进行测试，通过声发射方法确定失效。15 个试件粘结到具有水传输微通道的基底上，在水下用 3mm 活塞以 15Hz 的频率循环加载 500,000 次。
双向弯曲可以区分三种表面状况（p<0.05，方差分析）。单调测试不能区分各组。循环测试不能区分喷砂和酸蚀组，但两者都比抛光组弱。
粘结试件的咀嚼加载会由于粘结剂-陶瓷界面的贡献而产生不同于简单弯曲的应力状态。水会增加损伤累积效应。需要根据预期结果选择拉伸应力状态。
