Objective To evaluate the effects of different sand particle sizes of polishing disc on composite resin surface roughness and bacterial adherence.Methods Specimens of resins were randomly divided into five groups and polished with polishing burs (group A), and polishing discs of different particle sizes:70 μm particle size (group B), 50 μm particle size (group C), 30 μm particle size (group D) and 5 μm particle size (group E) respectively (n=10 for each group).Scanning electron microscopy (SEM) was used to observe the roughness and surface structure of the specimens.Bacterial adhesion on the surface of the specimens was calculated by CFU counting.Results Scanning electron microscopy (SEM) showed that with the decrease of particle size of polishing disc to 30 μm(group D), the grooves on the surface became shallower, and the number of pits were reduced in group D and E.There was a significant difference in bacterial adhesion between group D, E and that of group A (P<0.005).No significant difference was detected between group A,B and C (P>0.005).Conclusions With the decrease of the particle size of the polishing disc, lower surface roughness and fewer bacterial adhesion will be observed.Polishing disc with at least 30μm particle size can reduce bacterial adhesion of composite resin.%目的 研究不同砂粒粒径抛光碟对复合树脂抛光效果的影响.方法 将复合树脂(FiltekTM Z350)试件(n=50)随机分为5组(n=10):抛光车针组(A组)、70 μm粒径组(B组)、50 μm粒径组(C组)、30 μm粒径组(D组)、5 μm粒径组(E组),分别进行序列抛光.扫描电镜观察试件粗糙度及表面结构.计算不同试件表面的细菌粘附情况.结果 扫描电镜观察,随着抛光碟砂粒粒径的降低,序列抛光到D组(30 μm粒径)后,树脂试件表面沟痕明显变浅,凹坑减少.D组和E组的细菌粘附量与A组相比存在统计学差异(P<0.005);B 、C组与A组的细菌粘附量比较无统计学差异(P>0.005).结论 随着抛光碟砂粒粒径的减少,表面粗糙度降低,细菌粘附量下降;树脂材料表面至少序列抛光到30 μm粒径才能有效减少细菌粘附量.
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