学術論文
Er:YAGレーザーを用いた根管洗浄時に生じる根尖孔外への洗浄液の溢出量
―チップ挿入位置の影響―
2017 年 28 巻 2+3 号 p. 31-35
詳細
2017 年 28 巻 2+3 号 p. 31-35
Objective; The aim of the present study was to investigate the effect of tip insertion depth on the extrusion of irrigating solution during Er:YAG laser-activated irrigation （LAI） in comparison with passive ultrasonic irrigation （PUI） and conventional syringe irrigation （SI）.
Methodology; A root of an extracted human anterior tooth shaped to a working length of 15mm with apical size #40 and 0.06 taper was used. The root canal was then irrigated with water for 5 seconds with LAI, PUI or SI. In the LAI group, an Er:YAG laser unit （Erwin AdvErL, Morita） with a contact tip （R200T） was used at a power setting of 70mJ, 10pps. In the PUI group, an ultrasonic device （Piezon Master400, EMS） with a #20 file was used at the highest power setting. In the SI group, the canal was irrigated manually with a syringe and a 27G flat needle and 0.3ml of the irrigant. The tip insertion depth was set at 2, 5, or 10mm short of the working length in each group. Each irrigation was performed repeatedly seven times. To measure the actual volume of extruded irrigant, the root-end was covered with a piece of aluminum foil to collect the extruded irrigant, and the weight change of the aluminum foil was calculated using an electric balance （AE240, Mettler Toledo, Switzerland）. Data were analyzed by using one-way ANOVA and Games-Howell test at a significance level of p＝0.05.
Results; Shorter insertion depth of the laser tip during LAI generated significantly less apical irrigant extrusion （p＜0.05）. When the tip was positioned at 2 and 5mm short of the working length, the mean volume of extruded irrigant solution was PUI＜LAI＜SI （p＜0.05）. When the tip was positioned at 10mm short of the working length, the mean volume of extruded irrigant solution was LAI＝PUI＜SI （p＜0.05）.
Conclusions; Under the conditions of this study, the volume of extruded irrigant during LAI was significantly less than that during SI, and showed significant decreases with the decrease of tip insertion depth. When the insertion depth was set at 10mm short of the working length, the volume of extruded irrigant during LAI was similar to that during PUI.
