研磨和抛光对二硅酸锂玻璃陶瓷动态磨损行为影响的研究

Wear Performance of Lithium Disilicate Glass-ceramic after Grinding and Polishing Treatments

目的:研究模拟口腔环境下研磨和抛光对二硅酸锂玻璃陶瓷动态磨损行为的影响,为口腔临床操作提供参考。方法:制备直径3 mm、长8 mm的二硅酸锂玻璃陶瓷上试件和直径20 mm、厚4 mm的二硅酸锂玻璃陶瓷下试件各16个,将上、下试件随机分为两组,一组打磨至600目作为研磨组,另一组打磨至2000目作为抛光组,每组8个样本,在摩擦磨损试验机将上、下试件组成一对摩擦副,在人工唾液、室温环境、20 N载荷、转速100 r/min、回转半径2.5 mm、匀速圆周运动的条件下进行50万次循环磨损实验。在整个磨损周期中选取10个循环节点,用三维形貌仪测量每个节点圆盘试件的磨损高度损失量并绘制相应磨损曲线,再利用扫描电镜观察相应磨损阶段对应的磨损面微观形貌。结果:整个磨损过程中,各节点测量值显示研磨组二硅酸锂玻璃陶瓷的磨损量均大于抛光组二硅酸锂玻璃陶瓷的磨损量(P<0.05);两组二硅酸锂玻璃陶瓷的磨损曲线均呈现“跑合期”和“稳定磨损期”两个磨损阶段,研磨组的“跑合期”较抛光组的“跑合期”长,进入“稳定磨损期”的时间比抛光组迟。两组试件的微观形貌也呈现出与磨损曲线对应的两阶段规律。结论:在模拟口腔环境下,研磨组二硅酸锂玻璃陶瓷的磨损量显著高于抛光组,提示临床应重视戴牙时修复体的充分抛光以降低磨损、延长修复体使用寿命。

Objective To study the effects of grinding and polishing on the dynamic wear behavior of lithium disilicate glass ceramics in simulated oral environment,and provide reference for oral clinical operation.Methods Sixteen lithium disilicate glass ceramic cylinders with a diameter of 3 mm and a length of 8 mm and lithium disilicate glass ceramic discs with a diameter of 20 mm and a thickness of 4 mm were prepared,and the upper and lower test pieces were randomly divided into two groups.one group was polished to 600 mesh as the grinding group,and the other group was polished to 2000 mesh with polishing cloth with synthetic leather polishing pad as polishing group,each group of 8 samples,in friction and wear testing machine The friction pair was composed and 500,000 cycles of wear test were carried out under artificial saliva,room temperature environment,20 N load,rotation speed 100 r/min,radius of gyration 2.5 mm,and uniform circular motion.10 loop nodes were selected in the whole wear cycle.The wear height loss of each node disc specimen was measured by three-dimensional shape analyzer and the corresponding wear curve was drawn.Then the scanning surface was used to observe the wear surface corresponding to the wear phase.Results During the whole wear process,the measured values of each node showed that the wear amount of the lithium disilicate glass ceramics in the grinding group was larger than that in the polishing group lithium disilicate glass ceramics(P<0.05).The wear curve shows two wear stages:"running period"and"stable wear period".The"running period"of the grinding group is better than the"running period"of the polishing group,the time to enter the"stable wear period"is later than the polishing group.The microscopic morphology of the two sets of specimens also showed a two-stage law corresponding to the wear curve.Conclusion In the simulated oral environment,the wear of lithium disilicate glass ceramics in the grinding group is significantly higher than that in the polishing group,suggesting that the clinical should pay attention to the adequate polishing after the prosthesis is worn to reduce wear and prolong the life of the prosthesis.