不同光固化方法对可压型后牙树脂材料边缘适应性和显微硬度的影响(英文)

Effect of two light-curing modes on marginal adaptation and microhardness of packable posterior resin-based composites

背景:临床应用复合树脂进行牙科修复,主要依赖于其合适的固化与较小的体积收缩,而这与光固化方法密切相关。目的:探讨两种光固化方法对不同种类可压型后牙树脂显微材料的硬度和边缘密合性的影响。方法:EcuShere-Carat,3M Filtek P60,Tetric Ceram HB三种树脂通过弱光启动光固化模式和固化光强度维持不变的标准模式进行卤素固化灯光固化,采用扫描电镜测量树脂样本与充填容器的边缘裂隙宽度评价边缘密合性,使用维氏硬度计来测量各样本顶部和底部表面的硬度。结果与结论:Filtek P60和Tetric Ceram HB采用弱光启动光固化方式的边缘裂隙宽度小于采用标准的光固化模式(t=5.78,P<0.05;t=5.64,P<0.05)。但是对于Ecusphere-Carat,两种光固化方式效果接近(t=1.62,P>0.05)。不同树脂的顶部树脂表面硬度均大于底部树脂表面硬度(P<0.05)。弱光启动固化后,树脂顶部表面硬度较传统光固化低(P<0.05)。但两种光固化方式对于不同树脂底部表面硬度没有影响(P>0.05)。说明与常规光固化模式相比,弱光启动固化能有效降低部分可压型树脂的聚合收缩,树脂的表面硬度会有所下降。

BACKGROUND：The use of resin-based composites is increasing in clinical practice.The success and longevity of composite-resin restorations highly depends on adequate polymerization and small polymerization shrinkage,which are closely related with light-curing modes.OBJECTIVE：To investigate the effects of two different light-curing methods on marginal adaptation and microhardness of packable posterior composite restorations.METHODS：Specimens were made from these moulds with 3 types of packable resin-based composites：Ecusphere-Carat,3M Filtek P60 and Tetric Ceram HB,and 2 curing modes：standard and soft-start curing mode with halogen light.The marginal adaptation was evaluated by measuring the width of margin gap between the mold and specimens with scanning electron microscope.Vickers microhardness was tested on the top and bottom surfaces of the specimens.RESULTS AND CONCLUSION：For Filtek P60 and Tetric Ceram HB,soft-start curing mode showed lower values of the widths of marginal gap than that of standard mode（t=5.78,P 0.05;t=5.64,P 0.05）,but there was no significant difference with Ecusphere-Carat（t=1.62,P 0.05）.The top surface demonstrated higher microhardness values than the bottom surface in all experimental conditions（P 0.05）.The soft-start curing mode showed lower values of top surface hardness for the three resins than that of standard mode（P 0.05）.But no significant differences were found on the bottom surface hardness of the three resins between these two curing modes（P 0.05）.Compared with routine light-cured mode,the soft-start curing mode can reduce the polymerization shrinkage and surface hardness of packable resin-based composites.