Er,Cr:YSGG激光和酸蚀处理牙本质表面后的扫描电镜观察

目的 本文通过电镜观察，研究不同预备方法处理牙本质后表面形态的改变及树脂-牙本质界面形态的差别。方法 用10颗拔除的第三磨牙制作牙本质片，每个牙本质片预备三个窝洞，分别用传统方法加酸蚀预备，Er，Cr：YSGG激光预备及激光加酸蚀预备。将10个牙本质片分为A、B两组，A组在电镜下观察牙本质表面形态改变；B组用流动树脂充填，暴露树脂-牙本质界面，样本经处理后在电镜下观察比较。结果 A组：传统方法预备后牙本质表面可见开放的牙本质小管口；激光预备后开放的牙本质小管口呈现火山口样；激光加酸蚀处理后的牙本质小管周围呈现白晕。B组：传统预备方法的树脂一牙本质界面可见混合层，圆锥型树脂突和侧枝连接的形成；单纯激光预备后界面没有混合层的形成，形成的树脂突呈圆柱型，较长并且细密；激光加酸蚀处理后界面可见少量混合层形成，树脂突圆柱型，粗、长且有少量侧枝连接。结论 Er，Cr：YSGG激光加酸蚀处理后，开放的牙本质小管周围可见来完全脱矿的管周牙本质．树脂一牙本质界面可见混合层和粗长的圆柱形树脂突。

Scanning electron microscopic observation on changes of dentin prepared by Er,Cr:YSGG Laser and/or acid

Objective The aim of this study was to use scanning electon microscope (SEM) to describe the changes in morphological structure of the dentin surface and to evaluate the difference in interaction patterns between dentin and resin after laser and/or acid preparation.Methods Ten dentin disks were obtained from extracted third molars. Each disk contained three cavities; one was prepared with a conventional high-speed drill and treated with ~15% phosphoric acid; one was prepared by Er,Cr:YSGG laser with water cooling; and the other was prepared by laser and treated with 15% phosphoric acid. The ten dentin disks were assigned to two groups (n=5 each). The disks in group A were prepared for morphological analysis of the dentin surface. The disks in group B were restored with flowable resin and observed under SEM after dentin-resin interface demineralization and deproteinization.Results In Group A, the conventionally prepared dentin showed open dentinal tubules, while on the dentin surface prepared by Er,Cr:YSGG laser, the open dentinal tubules were observed to be crater-like. On the dentin surface prepared by laser plus acid, the dentinal tubules were open and encircled by a white line. In Group B, the dentin-resin interface of conventionally prepared cavity showed the formation of the hybrid layer, funnel shaped resin tags and adhesive lateral branches. The interface of the laser prepared cavity did not have a hybrid layer. The column shaped resin tags were thinner, longer and denser than that of the conventionally prepared cavity. The interface prepared by laser plus acid also showed the three layer structures seeh in the conventional preps, but the hybrid layer was thin and the resin tags were columnar in shape and long, the same as in the laser prepared cavities.Conclusion The dentin prepared by Er,Cr:YSGG laser plus acid showed open dentinal tubular encircled by partially demineralized peritubular dentin. The dentin-resin interface had the hybrid layer and long resin tags with a small taper.