牙科陶瓷循环和静态疲劳的对比实验  

A comparative study on cyclic and static fatigue of dental ceramic by means of Hertzian′s contact

作　　者：刘伟才[1] 巢永烈[2] 万乾炳[2] 黄承敏[1] 

机构地区：[1]同济大学口腔医学院修复科,上海200072 [2]四川大学华西口腔医学院修复科

出　　处：《中华口腔医学杂志》2005年第6期508-510,共3页Chinese Journal of Stomatology

摘　　要：目的比较牙科陶瓷循环和静态加载后的强度下降规律以及结构损伤差异。方法应用赫兹触压实验方法对可切削陶瓷标准试件(Vita markⅡ)进行循环和静态加载,测试试件的残余三点挠曲强度,观测试件表面及表面下损伤,数据进行单因素方差分析。结果试件在两种加载模式下,首次加载后残余强度均降低,同时出现外锥型损伤。循环加载至1000次时,内锥型损伤出现并伴随强度进一步降低,差异有统计学意义(P<0.05)。不同加载时间下的静态加载试件强度下降的差异无统计学意义,同时不伴随内锥状裂纹的产生。结论静态加载和循环加载都能降低陶瓷试件的强度,但循环加载使损伤更严重。Objective To compare the difference in strength degradation and morphology damage of brittle dental ceramic after static load and cyclic fatigue. Methods Hertzian＇s contact technique with a tungsten carbide sphere was used to investigate the response of feldspathic dental porcelain to static load and cyclic fatigue. All specimens were subjected to static or cyclic loading in moist environment. Furthermore the surviving strength of specimens was examined by the three-point test and the morphology damage was observed. Statistical analyses were performed with ANOVA and a P-value less than 0. 05 was considered to be significant. Results Outer cone crack and associated strength degradation simultaneously occurred both after the first cyclic loading and static loading. Up to 1 000 cycles, the specimens showed inner cone cracks and strength degradation was aggravated. No significant difference in the strength degradation among all static loading specimens and no inner cone cracks occurred in static loading specimens. Conclusions Both static and cyclic fatigue influence dental ceramic strength, but cyclic fatigue is more deleterious.

关 键 词：牙瓷料 抗压强度 疲劳 

分 类 号：R783.1[医药卫生—口腔医学]