齿科长石质饰瓷的二体与三体动态磨损表现

Two-and three-body dynamic wear performance of dental feldspathic porcelain

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 3×10^5 wear cycles,the wear depth was measured by 3D profilometer,and then a dynamic wear curve was plotted. Surface topography 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 exhibit more moderate tribological properties.