Application of Laser to Next Endodontics Prevented From Cracking

本研究的目的是研究Er：YAG激光和超声根管预备后根尖折裂的动力学和抗折性能。拔除的人前牙制备牙根，用牙胶侧方浓缩，根端切除。用水冷Er：YAG激光、最高功率超声装置水冷或最低功率水冷超声装置分别制备了3 mm深的根端腔。制备完成后，用显微镜和显微CT观察骨折的有无和形态变化。然后在万能试验机上垂直加载根管内的充填材料。超声组在最高功率设置下的折射率明显高于Er：YAG激光组和超声波组在最低功率设置下的水冷处理。在本实验的体外实验范围内，Er：YAG激光水冷照射根管预备根管后所引起的折裂最小，但Er：YAG光照射组与超声波组的阻力和垂直折断方式无显著差异。

The purpose of this study was to investigate the kinetics of root fractures produced byroot-end cavity preparation and the fracture resistance following root-end cavitypreparation using Er:YAG laser and ultrasonics. Roots of extracted human anteriorteeth were prepared, laterally condensed with guttapercha, and the root-end wasresected. Root-end cavities of 3 mm in depth were prepared using Er:YAG laser withwater cooling , an ultrasonic device at the highest power setting with or without watercooling, or at the lowest power setting with water cooling. After the preparation,presence or absence of fracture and morphological change were observed with amicroscope and a micro CT. Then, obturation materials in the root canal werevertically loaded using a universal testing machine. There were significantly morefractures in the ultrasonic group at the highest power setting group compared to theEr:YAG laser group and the ultrasonic group at the lowest power setting with watercooling. Within the limitations of thisin vitro experiment, fractures caused by Er:YAGlaser irradiation under water cooling for root-end cavity preparation was minimal.However, there were no significant differences in the resistance and vertical rootfracture patterns between the Er:YAG laser group and the ultrasonic group.