齿科长石质饰瓷的二体与三体动态磨损表现

摘要

目的：探究二体和三体服役环境对长石质饰瓷动态磨损行为的影响。方法：将12个长方体钴铬烤瓷试件随机分为PMMA三体磨损实验组和蒸馏水的二体磨损实验组（n＝6）。将试件分别固定于口腔疲劳磨损实验机夹具上，并与直径为10 mm的不锈钢小球对颌加载头相配副，加入相应介质溶液后采用350 N载荷、4 Hz频率进行240万次循环加载。以每30万次循环作为一个测试节点，利用三维形貌仪测量试件磨损高度的变化，综合各节点磨损量，形成二体和三体磨损的动态磨损曲线。扫描电镜观察不同磨损阶段各组饰瓷表面的微观形貌变化。结果：饰瓷在二体和三体环境中磨损曲线与微观形貌均呈现出“跑合期”、“稳定磨损期”及“剧烈磨损期”3个特征性的磨损阶段。但在二体磨损环境中饰瓷磨损量大，并表现出较长的跑合期及较短的稳定磨损期。结论：饰瓷的摩擦学行为存在动态演化3阶段的发展规律。磨料介质PMMA可能起到了一定的润滑作用，使饰瓷材料表现出较为温和的摩擦学特性。%AIM:To investigate the influence of two-body or three -body environment on the dynamic wear behavior of feldspathic porcelain.METHODS:12 cobalt-chromium porcelain rectangular specimens were made and randomly divided into PMMA three-body test group(n=6)and distilled water two-body test group(n=6).The specimens were attached to the jig of oral fatigue wear simulator.10 mm diameter stainless steel balls were served as antagonist cusp.The specimens were subjected to a total of 2.4 million wear cycles at 350 N,4 Hz.For every 3 ×105 wear cycles,the wear depth was measured by 3D profilometer,and then a dynamic wear curve was plotted.Surface to-pography of the porcelain specimens at different wear stages was observed by SEM.RESULTS:In both the two-body and the three-body environment,wear curves and the microstructure of porcelain showed the characteristic stages of“running-in period”,“steady wear period”and“severe wear period”.But in the two-body environment,porcelain had relatively more wear depth,a longer running-in period,and a shorter steady wear period.CONLIUSION:The wear characteristics of porcelain is dynamic.PMMA may play the role of lubricant in wear process making porcelain ex-hibit more moderate tribological properties.