纳米羟基磷灰石的制备及其对牙本质小管封闭效果的初步观察

目的 通过合成纳米羟基磷灰石(hydroxyapatite,HA)以及体外实验观察其对牙本质小管的封闭效果,为纳米HA的临床应用提供依据.方法 采用磷酸氢二铵(NH4)2HPO4]和硝酸钙Ca(NO3)2]合成纳米HA,扫描电子显微镜(scanning electron microscope,SEM)、透射电子显微镜(transmission electron microscope,TEM)、傅里叶变换红外光谱计(Fourier transform infrared spectrometer,FTIR)和X射线衍射仪(X-ray diffractometer,XRD)检测纳米HA.选取8颗健康第三磨牙制备24片牙本质薄片,按随机数字表分为酪蛋白磷酸肽钙磷复合体(casein phosphopeptideamorphous calcium phosphate,CPP-ACP)组、纳米HA组及空白对照组,每组8片;空白对照组不做处理,CPP-ACP组和纳米HA组每天分别用CPP-ACP和纳米HA处理牙本质薄片2次,7d后SEM观察牙本质表面.结果 经SEM、TEM、FTIR和XRD检测,证实本项实验制备的HA为纳米HA;SEM观察纳米HA对牙本质小管的封闭效果明显高于CPP-ACP组和窄白对照组.结论 在体外条件下,与CPP-ACP相比,纳米HA可更有效地封闭暴露的牙本质小管.

The preparation of nano-hydroxyapatite and preliminary observation on its effects on the occlusion of denfinal tubules

Objective To synthesize nano-hydroxyapatite(nano-HA)and evaluate its effect on the occlusion of dentinal tubules in vitro,and therefore provide evidence for the clinical application.Methods (NH4)2 HPO4 and Ca(NO3)2 were used to form nano-HA,which was characterized by scanning electron microscopy(SEM),transmission electron microscopy(TEM),Fourier transform infrared spectrometer (FTIR)and X-ray diffractometer(XRD)respectively.Twenty-four dentin slabs were obtained from 8 healthy third molars and randomly divided into 3 groups,which were control group,casein phosphopetide-amorphous calcium phosphate(CPP-ACP)group,and nano-HA group.After the CPP-ACP and nano-HA were topically applied to the slabs of two study groups twice a day for 7 days,the surface of slab dentin Was observed using SEM.Results SEM,TEM,FTIR,and XRD tests showed that nano-HA was synthesized successfully.SEM observations revealed that the sealing of dentinal tubules of nano-HA group was extremely high when compared with those of control and CPP-ACP group.Conclusions In comparison with CPP-ACP.nano-HA could occlude dentinal tubules more effectively in vitro.