根管拡大形成へのEr:YAGレーザーの応用について

抄録

Abstract : The purpose of this study was to evaluate the use of Er:YAG laser in root canal preparation in vitro. Six human extracted lower incisors were used. The root canals were enlarged mechanically up to a size of #35 and then were irradiated by Er:YAG laser (Erwin Adverl, Morita) using two kinds of cone-shaped fiber tips (R200T and R300T). The tip was moved 20 times from the apex to the orifice, at a speed of 1 mm/s, with water spray (8.5 mL/min). The output energy was 30 mJ with a pulse frequency of 25 pps. Before and after laser irradiation, the teeth were scanned by micro computed tomography (μ-CT). Thereafter, three-dimensional images of the teeth were reconstructed and the volume of root canals was calculated. Subsequently, the teeth were split longitudinally and observed under a scanning electron microscope (SEM). It was confirmed that the root canals were enlarged after laser irradiation. The mean rates of increase of root canal spaces were 112.97±3.75% after R200T application, and 148.99±11.15% after R300T application. SEM observation showed that irradiated areas had an undulating wave-like appearance and showed no smear layer. These results show that the Er:YAG laser is an effective tool for root canal preparation.