1 Effects of Nd:YAG Laser Irradiation with TiO2 Solution on Dentin Surface Observation of Morphological Change \ Tomoo ANJO, Hidetoshi SAEGUSA, Hidetoshi NOGUCHI*, Arata EBIHARA and Hideaki SUDA Pulp Biology and Endodontics, Graduate School, Tokyo Medical and Dental University (Chief:Prof.Hideaki *MANI Inc SUDA) (Received:June 30, Accepted for Publication:July26,2005) Abstract:Recently, a fine flexible glass fiber made of quartz has been developed to transmit laser beams more effectively, which permits energy to be concentrated in a specific area This has increased the potential usefulness of the Nd:YAG laser in root canal treatment, and so it is expected that the Nd:YAG laser will be increasingly employed in the dental clinic, especially in the field of endodontics. This investigation evaluated the effects of Nd:YAG laser irradiation with TiO2 solution on dentin surface and fiber tip by light microscopy and electron microscopy. Dentin disks were prepared from the crown of bovine teeth. The optical fiber was processed by irradiating Nd:YAG laser (MDLNd8, MANI) through itself for 30 sec in TiO2 solu tion. The specimens were irradiated using the following parameters:pulse energy of 200mJ, 300mJ and 350mJ at 20 pulses per sec, and irradiation time of 5 sec. Samples and the processed fiber were observed under a light microscope and a scanning electron microscope (SEM), and the depth and width of cavities were evaluated using a CCD laser sensor (LB02, KEY ENCE). No carbonization was observed for the processed fiber, the tip of which had become conical. The irradiated beam pattern was changed from straight to spherical after processing the fiber. The mean depths of cavities were 125 }68/um (200mJ 20pps), 155 }89um (300mJ 20pps) and 243 } 66um (350mJ 20pps), respectively. The mean widths of cavities were 185 }75um (200mJ 20pps), 297 }128um (300mJ 20pps) and 422 }156um (350mJ 20pps), respectively. The SEM obser vation showed that vaporized dentin was hardly found in the 200mJ group. Vaporized dentin and no carbonization were found in the 300mJ group, and vaporized dentin and little carbonized dentin were found in the 350mJ group. These results suggest that Nd:YAG laser irradiation with a processed fiber and TiO2 solution could vaporize dentin safely and effectively. (J.Jpn. Soc. Laser Dent. 16:80 `85, 2005 Reprint request to Dr.ANJO) Key words=nd:yag laser, TiO2, Dentin
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