牙科可切削聚醚醚酮表面抛光性能的初步研究

Polishing performance of dental milled polyetheretherketone:An in vitro study

目的研究牙科可切削聚醚醚酮(PEEK)抛光前后表面微观形貌与粗糙度值变化,并与临床可切削临时冠桥树脂聚甲基丙烯酸甲酯(PMMA)抛光效果进行比较,探讨牙科可切削聚醚醚酮是否能满足临床抛光性能要求。方法选择牙科可切削聚醚醚酮材料作为实验组(PT组),以可切削临时冠桥树脂材料作为对照组(R组),通过数字化铣削技术将两者加工为圆盘形试件(直径10 mm,厚度2 mm)各7个;所有试件表面经研磨机砂纸打磨平整后,采用同一种牙科抛光系统对其表面进行抛光;每组试件分别编号为1~7,使用Excel软件生成2个1~7的随机整数,抽取随机数对应的2个试件,使用扫描电镜(SEM)观察试件抛光前后的表面形貌。使用原子力显微镜(AFM)对2组剩余的5个试件抛光前后分别进行表面扫描,观察各试件表面形貌并得到粗糙度Ra值,对各组组内抛光前后试件的Ra值进行配对样本t检验,2组间抛光前后Ra值数据进行独立样本t检验分析。结果通过SEM及AFM均可观察到,PT组及R组试件抛光后较抛光前表面形貌更加平整;使用AFM测得PT组抛光前Ra=(0.047±0.016)μm,抛光后Ra=(0.022±0.003)μm,R组抛光前Ra=(0.036±0.011)μm,抛光后Ra=(0.018±0.008)μm;2组材料抛光前与抛光后其Ra值均差异无统计学意义(t_(抛光前)=1.075,P_(抛光前)=0.309;t_(抛光后)=3.562,P抛光后=0.070),但同种材料抛光后的试件的Ra值明显降低,抛光前后的Ra值差异具有统计学意义(t_(PT组)=5.851,P_(PT组)<0.001;t_(R组)=5.166,P_(R组)<0.001)。结论抛光处理可显著降低牙科可切削聚醚醚酮Ra值,与牙科可切削冠桥树脂抛光效果相近,其性能可达到口腔修复体临床抛光要求。

Objective In this in vitro study,the effect of polishing protocols on the surface morphology and roughness of the dental⁃milled polyetheretherketone(PEEK)was evaluated,compared with the clinical⁃milled polymethylmethacrylate(PMMA)for crowns and bridges,so as to confirm whether the dental⁃milled PEEK can meet clinical requirements.Methods Two kinds of milled specimens were included in this study:dental milled PEEK(PT group)as the test group and clinical⁃milled PMMA for crowns and bridges(R group)as the control group.A total of seven specimens of each material were milled as cylinders with the diameter of 10 mm and the height of 2 mm.All specimens were ground using SiC paper and polished with the same polishing protocol.Among the seven specimens,two were randomly chosen.A scanning electron microscope(SEM)was used to observe the surface morphology of the specimens before and after polishing.The left five specimens were subjected to atomic force microscope(AFM)to measure the surface roughness(Ra)before and after polishing.Paired t⁃test was used to compare the mean values of Ra before and after polishing in each group.Independent sample t⁃test was used for comparison between the two groups.Results After polishing,each group showed a more regular surface.The Ra value of PT group decreased from(0.047±0.016)μm to(0.022±0.003)μm(t_(before)=1.075,P_(before)=0.309;t_(after)=3.562,P_(after)=0.070).The Ra value of R group decreased from(0.036±0.011)μm to(0.018±0.008)μm(t_(PT group)=5.851,P_(PT group)<0.001;t_(R group)=5.166,P_(R group)<0.001).No statistical difference in Ra value was found between groups after polishing.There was statistical difference in Ra value for each group.The Ra value of each group decreased after polishing.Conclusions Dental⁃milled PEEK could get lower surface roughness after polishing.No statistical difference in Ra values was observed between the dental⁃milled PEEK and the clinical⁃milled PMMA for crown and bridge after polishing.Dental⁃milled PEEK can meet the clinical requirements.