新型试样固定装置在微拉伸测试中的应用

New fixation set-up designed for micro-tensile test

目的:介绍一种新型的条状试样固定方式,应用于微拉伸测试粘接强度。方法:以临床常用牙科粘接剂Adper TM Single Bond 2(SB2)制作树脂-牙本质粘接试件,切割成条状试样,随机分为2组进行微拉伸强度测试:Ciucchi's夹具(对照组)和本试验装置(实验组),场发射扫描电镜观察试样断裂界面,卡方检验分析断裂模式;建立固定装置及夹具的三维有限元模型,计算机模拟分析拉伸试验中试样应力分布方式。结果:实验组与对照组的粘接强度(MPa)分别为32.76±7.43和43.58±4.72(P<0.05);实验组和对照组粘接界面混合断裂模式分别为28/36和20/36(P<0.05);有限元分析结果显示实验组在测试过程中拉伸力沿试样长轴传导,垂直粘接界面,断裂界面应力分布均匀。结论:该实验介绍的条状试样固定方法实用于微拉伸强度应力的测定。

Objective： To introduce a new fixation set-up for micro-tensile test. Methods： Dentin-composite were bonded with AdperTM Single Bond 2 （SB2） and sectioned into stick-shaped specimens. Specimens from each tooth （n = 6） were equally divided into Ciucchi jig and the designed set-up （Control and experimental） groups for micro-tensile bond test according to the utilized fixa- tion set-up. The bonding interface failure mode was examined with field-emission scanning electron microscope （FESEM）. Three- dimensional models of the two set-ups and the specimen were developed, stress distribution was analyzed by finite element analysis （FEA）. Results ： The bond strength（MPa） of experimental and control group was 32.76 ± 7.43 and 43.58 ± 4.72 （ P 〈 0.05 ）, the ratio of mixed failure was 28/36 and 20/36（P 〈 0.05 ） respectively. FEA showed that the designed set-up for fixing the sticks pro- vided a uniform stress distribution along the long axis of the specimen. FEA and failure mode analysis confirmed such uniform distri- bution was also concentrated at the bonding interface. Conclusion： The new set-up is feasible for micro-tensile test.