Basic Study of the Relationship between Root Canal Irradiation Tip Distance and Irradiation Energy

The Er:YAG laser is useful in endodontic treatment compared with conventional methods, resulting in disinfection of the root canal and elimination of smear layers including bacteria and debris. An irradiation tip for root canal treatment has been developed; it can be used to perform lateral ablation using 20% power in the forward direction and 80% power in the lateral direction. However, the relationship between energy loss and distance of the endodontic irradiation tip was unclear. The aim of this study was to evaluate irradiation energy loss with change in distance, using an Er:YAG laser apparatus (Erwin AdvErL, J. Morita, Kyoto) and irradiation tip (R200T, J. Morita, Kyoto). The laser sensor (LMP10LP, COHERENT Inc., Portland) was placed vertically or horizontally at the irradiation tip. The irradiation energy was measured three times using a laser power meter (Field Master-GS, COHERENT Inc., Portland). The distance between the irradiation tip and sensor was varied from 1.0 to 10.0 mm. Irradiation energy was found to be inversely proportional to distance. An energy change was not clearly observed with low energy irradiation (30 mJ), however, a high energy (50 mJ and 70 mJ) setting has decrease of energy for influence distance. The lateral position was more greatly affected by the change in distance than the vertical position. These results suggested that the energy of the new irradiation tip varied in both the vertical and horizontal directions. (J. Jpn. Soc. Laser Dent. 23:86 ~ 89, 2012 Reprint requests to Dr. TAKAMORI) Key words= Er:YAG laser, Root canal irradiation tip, Energy alteration, Distance キーワード= Er:YAGレーザー,根管照射用チップ,出力変化,距離