The Effect of the Er: YAG Laser on the Tongue of Rat

Abstract

Clinical application of the Er: YAG Laser for dental caries and periodontal treatment has been developed. In clinical use, the effect of mis-irradiation of the Er: YAG Laser on the surrounding tissues should be considered. The purpose of this study was to examine the effect of the Er: YAG Laser on soft tissues supposing the side effect of mis-irradiation. The Er: YAG Laser was irradiated against the tongue of rat under following various conditions; the energy level: 50, 150, 300mJ/pulse, pulsing time: 1 and 10 pulses, irradiation distance: 0, 5, 10 and 20mm, and irradiated field: wet or dry. Wounds on tongue were observed macroscopically at 0, 1, 3, 7 and 14 days after laser irradiation. Some specimens were also examined by SEM. The following results were obtained: contact irradiations caused limited damages to tongue regardless of water irrigation; however, the depth of wounds depended upon the pulsing time and power level of the laser, while, non-contact irradiation showed a little or no effect against tongue. Moreover, the use of water irrigation decreased their damages effectively. With respect to wound healing, all cases were shown as normal process. Clinically, most of mis-irradiations are supposed to happen with non-contact irradiation under water spray. These results indicate that the Er: YAG Laser application for intraoral usage would be safe for the surrounding soft tissues within the usual power setting in dental treatment.(J. Jpn. Soc. Laser Dent. 7: 46-57, 1996 Reprint requests to Dr OHNO)