抛光对复合树脂磨损表面微机械性能及材料后续磨损行为的影响

Effect of polishing on the micro-mechanical properties and subsequent wear behavior of dental composite

目的:对处于稳定磨损期的复合树脂材料进行抛光处理,之后再次进行循环磨损测试,评估抛光对材料表面微机械性能及后续磨损行为的影响。方法:制作直径12mm,厚2.4mm的Z350复合树脂圆盘15个,与滑石瓷配副,在人工唾液环境下进行载荷20N、频率5HZ,磨程6mm的线性往复循环磨损试验约240min,绘制磨损曲线。磨损后随机抽取10个样本,分为2组。一组利用标准实验室抛光步骤对磨损面进行抛光处理;另一组采用OptraPol树脂抛光套装对磨损表面抛光。之后再次进行上述循环磨损测试。利用纳米压痕仪对材料原始状态、磨损后、实验室抛光及临床抛光后的表面进行纳米硬度、弹性模量检测。电镜观察表面微观结构。结果:磨损后进行实验室抛光,树脂表面硬度(H:0.52±0.06)可恢复至初始状态(H:0.56±0.03),材料本身与对颌的稳定磨损状态被打破。因此,磨损行为与初始状态相似,可见明显的跑合期,摩擦系数也较为接近。而采用临床抛光手段,树脂表面硬度仅提升至0.30±0.08,且呈现较为缓和的磨损行为,摩擦系数较低。结论:使用临床手段对磨损的树脂修复体表面进行适当抛光处理,不会打破其本身的稳定磨损状态。但实验室手段抛光后,树脂表面的稳定磨损状态将被破坏。故应避免过度的抛光,防止树脂修复体重新经历从跑合到稳定的磨损过程。

Objective:To evaluate the effect of polishing on the micro-mechanical properties and subsequent wear behavior of the dental composite resin.Methods:Fifteen Z350 composite resin discs with a diameter of 12 mm and a thickness of 2.4 mm were prepared,and a linear reciprocating cyclic wear test with a load of 20 N,a frequency of 5 HZ and a stroke of 6 mm in artificial saliva was performed with steatite antagonist for about 240 minutes.And the wear curve was plotted.After the wear test,10 samples were selected and divided into 2 groups randomly.In the first group,the worn surface was polished with the standard laboratory polishing step;the specimens in the other group were polished using an OptraPol resin polishing kit.The above cyclic wear test was then performed again.Nano hardness and elastic modulus of the material were measured using a nano-indenter:before wear,after abrasion,after laboratory polishing and after clinical polishing.Surface microstructure of samples were observed by the scanning electron microscopy.Results:After laboratory polishing treatment,the hardness of the composite(H:0.52±0.06)was restored to the initial state(H:0.56±0.03),and the steady wear state of the material and its antagonist could not be sustained.Therefore,the wear behavior was similar to the initial state,and an obvious running-in stage could be observed again,the friction coefficient was also similar to the initial state.While,the hardness of the resin only increased to 0.30±0.08 after clinical polishing,and presented a mild wear behavior with relatively low friction coefficient.Conclusions:Polishing the worn surface of dental composite appropriately in clinical will not affect its steady wear state.However,when the worn surface was polished with the standard laboratory polishing step,the steady wear state of the material and its antagonist could not be sustained.Therefore,excessive polishing should still be avoided to prevent the composite restoration from re-experiencing the running-in period.