Hossain M, Nakamura Y, Yamada Y, Kimura Y, Nakamura G, Matsumoto K
Department of Endodontics, Showa University School of Dentistry, 2-1-1 Kitasenzoku, Ohta-ku, Tokyo, Japan.
J Clin Laser Med Surg. 1999 Jun;17(3):105-9. doi: 10.1089/clm.1999.17.105.
This investigation was performed quantitatively to determine the ranges of ablation and to evaluate the morphological changes in human enamel and dentin irradiated by Er:YAG laser with or without water mist.
Recently, several infrared lasers have been introduced in the dental clinic to remove carious dental hard tissues in anticipation of replacing the high-speed dental drill. Among them, the Er:YAG laser has shown the most promise for hard tissue ablation.
An Er:YAG laser was used to ablate human dental hard tissues using a pulse energy that ranged from 100 to 400 mJ at a frequency of 2 Hz for 5 seconds. Ablation rates with or without water mist at different pulse energies were measured, and the morphological changes on enamel and dentin were also investigated by stereomicroscopy and scanning electron microscopy (SEM).
The relationship between ablation depths and energies was almost linear at both enamel and dentin samples. The irradiation with water mist reduced the ablation depths, but only minimally, when compared to those irradiated without water mist. Morphological findings by SEM indicated that Er:YAG laser irradiation with water mist could produce the cavities without signs of thermal damage to the surrounding enamel and dentin.
The results of this study suggest that addition of a fine water mist directed at the ablation sites does not greatly decrease the ablation, and does not cause any carbonization and melting in the surrounding dental hard tissues.
本研究进行定量分析，以确定消融范围，并评估在有或没有水雾情况下，铒钇铝石榴石（Er:YAG）激光照射人牙釉质和牙本质后的形态变化。
最近，牙科诊所引入了几种红外激光，以期取代高速牙钻来去除龋坏的牙齿硬组织。其中，Er:YAG激光在硬组织消融方面最具潜力。
使用Er:YAG激光以2赫兹的频率、100至400毫焦的脉冲能量对人牙硬组织进行5秒钟的消融。测量不同脉冲能量下有无水雾时的消融率，并通过体视显微镜和扫描电子显微镜（SEM）研究牙釉质和牙本质的形态变化。
牙釉质和牙本质样本的消融深度与能量之间的关系几乎呈线性。与无水雾照射相比，有水雾照射时消融深度有所降低，但降幅很小。SEM的形态学结果表明，有水雾时Er:YAG激光照射可形成龋洞，且周围牙釉质和牙本质无热损伤迹象。
本研究结果表明，在消融部位添加细水雾不会大幅降低消融效果，也不会导致周围牙齿硬组织出现碳化和熔化现象。
