论文部分内容阅读
目的观察Er∶YAG激光不同频率和照射时间对牙体硬组织切割效率和表面形态的影响。方法 80个牙釉质样本和80个牙本质样本分别按照射时间10 s和20 s,使用随机数字表法分为两组(n=40),每组再分为5个亚组(n=8),分别用频率为10、15、20、25、30 Hz Er∶YAG激光对每个样本进行照射,体视显微镜测量牙釉质和牙本质凹坑直径、深度,扫描电镜观察牙釉质和牙本质表面形态。结果 Er∶YAG激光频率10~20 Hz、照射时间10 s及20 s时,牙釉质和牙本质凹坑的直径、深度随频率增加和照射时间延长而增加(P<0.05);Er∶YAG激光频率25~30 Hz、照射时间10 s及20 s时,牙釉质和牙本质凹坑的直径、深度随频率增加和照射时间延长出现缓慢增加的趋势(P>0.05)。扫描电镜下观察,牙釉质和牙本质表面形态发生了一定的变化,Er∶YAG激光频率为25~30 Hz时,牙釉质和牙本质表面出现裂纹、熔融等热损伤现象。结论 Er∶YAG激光适宜的频率和照射时间不仅可以获得牙体硬组织良好的切割效率,而且不会引起牙体硬组织表面形态热损伤。
Objective To observe the effect of Er:YAG laser on the cutting efficiency and surface morphology of dental hard tissue with different frequencies and irradiation time. Methods 80 enamel samples and 80 dentin samples were divided into two groups (n = 40) by random number table according to the irradiation time of 10 s and 20 s, and each group was divided into 5 subgroups (n = 8 ) Were used to irradiate each sample with 10, 15, 20, 25 and 30 Hz Er:YAG laser respectively. The diameters and depths of enamel and dentin pits were measured by stereo microscope and the enamel and dentin were observed by scanning electron microscope Surface morphology. Results The diameter and depth of enamel and dentin pit increased with the increase of frequency and irradiation time (P <0.05) when Er: YAG laser frequency was 10 ~ 20 Hz, irradiation time was 10 s and 20 s. Er: YAG laser The diameters and depths of enamel and dentin pit increased slowly with the increase of frequency and irradiation time (P> 0.05) at the frequency of 25-30 Hz and irradiation time of 10 s and 20 s. Scanning electron microscopy showed that the morphology of enamel and dentin surface changed a certain amount. At the frequency of Er: YAG laser of 25 ~ 30 Hz, the enamel and dentin surface were cracked and melted. Conclusion The suitable frequency and irradiation time of Er:YAG laser can not only obtain good cutting efficiency of dental hard tissue, but also can not cause thermal damage to dental hard tissue surface.