Nd：YAG激光照射对牙本质表面微观特征影响的实验研究

目的：研究不同剂量Nd：YAG激光照射后，牙本质小管封闭深度及不同深度内钙磷比值的变化，得出Nd：YAG激光治疗牙本质过敏症的最佳参数。方法：酸蚀法建立牙本质敏感模型，应用不同参数的Nd：YAG激光照射样本，A组（0 mj，0 Hz，对照组）；B组（30 mj，5 Hz）；C组（30 mj，10 Hz）；D组（50 mj，5 Hz）；E组（50 mj，10 Hz）。照射完成后将样本纵剖，扫描电镜观察照射前后样本牙本质小管封闭深度并用X?线能谱分析不同深度处样本钙磷比值变化。结果：扫描电镜见B组牙本质小管表面封闭，近表面处小管直径比对照组变小。 C、D两组牙本质小管熔融达一定厚度，且牙本质结构完整。 E组牙本质熔融厚度达25μm，但熔融区中有微孔产生。 X线能谱分析各组样本5μm、20μm深处的钙磷比值，差异无统计学意义。结论：Nd：YAG激光牙本质脱敏的较为理想参数为（30 mj，10 Hz）和（50 mj，5 Hz）。

The experimental study on the effect of dentine micro-characteristic features after irradiating with Nd:YAG laser

Objective:To evaluate the dentine micro-characteristic change after irradiating with Nd:YAG laser. Methods:The dentin hypersensitivity model was setted up by Acid etching. And then the samples were irradiated by Nd:YAG laser under different parameters. The morphological alterations and the calcium-phosphorus ( Ca/P) ratio in different depth of the dentin were examined with SEM combined with energy dispersive X-ray microanalysis. Results:At the longitu?dinal section of samples,the dentinal tubules were blocked and with smaller diameter of tubules near the dentine surface at group B compared with the control group. Dentinal tubules were blocked to a certain depth and no damage at group C and D. The tubules were blocked from surface to the 25μm deepth and had many micro-cracks around the tubules at group E. Compared with the control group,the Ca/P ratios at 5μm and 20μm deepth were a little different but there was no statistically significant(P>0. 05). Conclusion:The suitable energy parameter of Nd:YAG laser seem been 30 mj,10 Hz and 50 mj , 5Hz during treating dentin hypersensitivity.