Kokuzawa Chizuko, Ebihara Arata, Watanabe Satoshi, Anjo Tomoo, Bolortuya Gombo, Saegusa Hidetoshi, Suda Hideaki
Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
Photomed Laser Surg. 2012 Jul;30(7):367-73. doi: 10.1089/pho.2012.3226. Epub 2012 Jun 12.
The purpose of the present study was to investigate the degree of Er:YAG laser irradiation at the apical area in vitro.
Since the laser was developed, advancement of laser treatment has been seen in various fields. However, few reports exist on shaping of the root canal using Er:YAG laser irradiation.
Six single-rooted human teeth were used. The working length of root canals was set at 6.5 mm, and they were enlarged to apical file size #25. An Er:YAG laser and cone-shaped irradiation tips (R135T and R200T) were used. Laser irradiation conditions were 30 m J, 20 pps, and water flow of 5 mL/min. Samples were irradiated three times for 10 sec each using each tip. To evaluate the cutting degree of horizontal area of the root canal, the laser-irradiated surfaces were observed using microfocus X-ray computed tomographic photography before and after every irradiation. The samples were observed under a scanning electron microscope. Measurement of pixels in an area was performed by image-editing software (Adobe Photoshop 7.0). Statistical analysis was performed using StatView (version 5.0). One-way ANOVA and the Tukey-Kramer tests were used; p<0.05 indicated statistical significance.
When root canals were irradiated with R200T for 10 sec (p<0.05), a large amount of evaporation (0.12 ± 1.07 mm(2)) was acquired in their cut area compared with the other irradiation conditions. In scanning electron microscopic observation, there was no smear layer and the dentinal tubules were open.
When the distance between the tip and root dentin was adjacent, the shaping of root dentin by Er:YAG laser irradiation was definitely observed.
本研究旨在体外研究铒钇铝石榴石（Er:YAG）激光对根尖区域的照射程度。
自激光问世以来，激光治疗在各个领域都有了进展。然而，关于使用Er:YAG激光照射进行根管塑形的报道很少。
使用六颗单根人牙。将根管工作长度设定为6.5毫米，并将其扩大至根尖锉号#25。使用一台Er:YAG激光及锥形照射头（R135T和R200T）。激光照射条件为30毫焦、20脉冲/秒，水流速度为5毫升/分钟。每个照射头对样本每次照射10秒，共照射三次。为评估根管水平区域的切割程度，在每次照射前后使用微焦点X射线计算机断层摄影观察激光照射表面。在扫描电子显微镜下观察样本。通过图像编辑软件（Adobe Photoshop 7.0）对一个区域内的像素进行测量。使用StatView（5.0版）进行统计分析。采用单因素方差分析和Tukey-Kramer检验；p<0.05表示具有统计学意义。
当用R200T照射根管10秒时（p<0.05），与其他照射条件相比，其切割区域有大量蒸发（0.12±1.07平方毫米）。在扫描电子显微镜观察中，没有玷污层，牙本质小管开放。
当照射头与牙根牙本质之间的距离相邻时，可明确观察到Er:YAG激光照射对牙根牙本质的塑形效果。
