不同粒径和形貌的羟基磷灰石对牙本质小管的堵塞作用及耐磨性研究

目的 从定性和定量两方面研究不同粒径和形貌的羟基磷灰石(Hydroxyapatite,HA)对牙本质小管的堵塞作用及其耐磨性.方法 选择人前磨牙40颗,以高速手机制取牙本质片并抛光,酸蚀后随机均分为4组:20 nm HA组;30 nm HA组;12μm HA组;空白对照组(不使用任何实验品).各组分别用对应的材料刷洗牙本质片表面7d.将牙本质片一分为二,一半扫描电镜观察;另一半进行刷牙磨耗实验后扫描电镜观察,应用Image-Pro Plus 6.0图像分析软件计算牙体质小管堵塞率.结果 扫描电镜下见牙本质小管被颗粒状物堵塞,堵塞率达82%~96%,平均堵塞率为30 nm HA组(短棒状)>20 nm HA组(针状)>12μm HA组(球形).牙刷磨耗实验后,扫描电镜下见牙本质表面沉积层光滑致密,仍有63%以上的小管被封闭.结论 30 nm短棒状HA、20 nm针状HA及12μm球形HA对牙本质小管均具有良好的堵塞作用及耐磨性.

The blocking effect and abrasion resistance of hydroxyapatite with different particle sizes and morphologies for dentinal tubules

Objective To study the blocking effect and abrasion resistance of hydroxyapatite (HA) with different particle sizes and morphologyies on dentinal tubules from the qualitative and quantitative aspects. Methods Dentin discs were etched and divided into 4 groups randomly: 20 nm HA group; 30 nm HA group; 12 μm HA group; control group (without any experimental treatment). Each group was brushed with correspondent materials for 7 days. Then, the dentin disk was divided into two parts, the one was detected by the scanning electron microscopy (SEM);the other was observed by SEM after toothbrush abrasion test. The Image-Pro Plus 6.0 image analysis software was used to calculate the plugging rate of dentinal tubules. Results SEM showed that the blockage is granular, the plugging rate of the den-tinal tubules were about 82%to 96%. 30 nm HA group (short rod) range the first in the average plugging rate, followed by the 20 nm HA group (needles) and 12μm HA group (spherical). After mechanical brushing for 7 days, SEM images showed that deposited layer in each group was smooth and compact, and more than 63% of the tubules still had been blocked. Conclusion HA with different particle sizes and morphologies had good plugging effect and abrasion resis-tance on dentine tubules. The blocking effect of HA was affected not only by particle size but also by the morphology.