Visualization of Irrigant Flow and Cavitation Induced by Er:YAG Laser within a Root Canal Model
Visualization of Irrigant Flow and Cavitation Induced by Er:YAG Laser within a Root Canal Model
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DOI：
10.1016/j.joen.2011.02.035
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发表时间：
2011-06-01
影响因子：
4.2
通讯作者：
Akamine, Akifumi
中科院分区：
文献类型：
--
作者：
Matsumoto, Himeka;Yoshimine, Yoshito;Akamine, Akifumi
激光激活灌洗（LAI）作为一种创新的根管灌洗方法，近年来得到了广泛的应用。然而，关于Er:YAG激光器的清洁机理的信息有限。在这项研究中，我们可视化了激光诱导气泡和体外流体流动的作用，以更好地了解LAI的物理机制。方法：Er:YAG激光器采用新型锥形尖端，侧向发射率约为80%。激光发射的脉冲能量为30,50或70mj（输出能量：11,18或26mj），重复频率为每秒1或20个脉冲，没有空气或水喷雾。在高速摄像机下，用玻璃珠示踪剂观察根管模型内的流体流动动力学。此外，在自由水和根管模型中都可以看到激光诱导的气泡图案。结果：示踪剂显示了液体的高速运动。我们清楚地观察到蒸汽和二次空化气泡膨胀和内爆的完整周期。在自由水中，蒸汽泡膨胀了220微秒，其形状类似于苹果。在根管模型中，蒸汽泡沿根管壁垂直方向膨胀，气泡膨胀持续时间为>= 700微秒。此外，在运河模型中产生的空化气泡比在自由水中产生的空化气泡要频繁得多。结论：Er:YAG激光在根管内的清洁机制可能与激光诱导的气泡膨胀和内爆引起的快速流体运动有关。（J end 2011;37:839-843）
Introduction: Laser-activated irrigation (LAI) has recently been introduced as an innovative method for root canal irrigation. However, there is limited information about the cleaning mechanism of an Er:YAG laser. In this study, we visualized the action of laser-induced bubbles and fluid flow in vitro to better understand the physical mechanisms underlying LAI. Methods: An Er:YAG laser was equipped with a novel cone-shaped tip with a lateral emission rate of approximately 80%. Laser light was emitted at a pulse energy of 30, 50, or 70 mJ (output energy: 11, 18, or 26 mJ) and a repetition rate of 1 or 20 pulses per second, without air or water spray. Fluid flow dynamics in a root canal model were observed by using glass-bead tracers under a highspeed camera. Moreover, laser-induced bubble patterns were visualized in both free water and the root canal model. Results: Tracers revealed high-speed motion of the fluid. A full cycle of expansion and implosion of vapor and secondary cavitation bubbles were clearly observed. In free water, the vapor bubble expanded for 220 microseconds, and its shape resembled that of an apple. In the root canal model, the vapor bubble expanded in a vertical direction along the canal wall, and bubble expansion continued for >= 700 microseconds. Furthermore, cavitation bubbles were created much more frequently in the canal model than in free water. Conclusions: These results suggest that the cleaning mechanism of an Er:YAG laser within the root canal might depend on rapid fluid motion caused by expansion and implosion of laser-induced bubbles. (J Endod 2011;37:839-843)