牙科Vita markⅡ可切削陶瓷赫兹触压循环疲劳研究  

Cyclic Fatigue of Vita Mark Ⅱ Machinable Ceramics under Hertzian′s Contact

作　　者：刘伟才[1] 张志升 黄承敏[1] 巢永烈[3] 万乾炳[3] 

机构地区：[1]同济大学口腔医院修复科,上海200072 [2]厦门市口腔医院修复科,福建厦门361003 [3]四川大学华西口腔医院修复科,四川成都610041

出　　处：《华西口腔医学杂志》2006年第4期306-308,共3页West China Journal of Stomatology

基　　金：高等学校博士学科点专项科研基金资助项目(9845)

摘　　要：目的研究VitamarkⅡ可切削陶瓷在赫兹触压循环加载下的疲劳模式。方法应用半径为3.18mm的碳化钨球对VitamarkⅡ可切削陶瓷标准试件进行循环加载,然后测试加载后试件残余三点的弯曲强度,观测试件表面及次表面的损伤情况。结果在相对均质的VitamarkⅡ可切削陶瓷赫兹触压循环疲劳中存在两种损伤模式,即经典的张应力驱动的锥状裂纹(脆性模式)及剪切应力驱动的显微损伤的累积(类塑性模式),前者以加载点周围同心圆样锥状裂纹为特征,后者产生继发性锥状裂纹和放射状裂纹。锥状裂纹的产生导致试件强度的首次下降,后继的更为严重的强度下降由放射状裂纹引起。结论牙科VitamarkⅡ可切削陶瓷赫兹触压循环疲劳包括低循环周期下的脆性模式以及高循环周期下的类塑性模式。Objective To investigate the cyclic fatigue modes of Vita mark Ⅱ machinable ceramics under Hertzian＇s contact. Methods Hertzian＇s contact technique （WC spheres r=3.18 mm） was used to investigate the cyclic fatigue of Vita mark Ⅱ machinable ceramic. All specimens were fatigued by cyclic loading in moist environment, furthermore, surviving strength was examined by three point test and morphology damage observation. Results In homogeneous Vita mark Ⅱ machinable ceramics, two fatigue damage modes existed after cyclic loading with spheres under moist environment, including conventional tensile-driven cone cracking （brittle mode） and sheardriven microdamage accumulation （quasi-plastic mode）. The latter generated radial cracks and deeply penetrating secondary cone crack. Initial strength degradation were caused by the cone cracks, subsequent and much more deleterious loss was caused by radial cracks. Conclusion Cyclic fatigue modes of Vita mark Ⅱ machinable ceramics includes brittle and quasi-plastic mode.

关 键 词：VITA MARK Ⅱ可切削陶瓷 赫兹触压 疲劳 

分 类 号：R783.1[医药卫生—口腔医学]