OBJECTIVE: This study was performed to compare the apical leakage degree after laser treatment and obturation with that without laser treatment, and to evaluate the efficiency of argon laser irradiation in removing debris and smear layer from the prepared root canal walls in vitro. SUMMARY BACKGROUND DATA: There has been no report of laser effect on apical leakage after laser treatment and obturation. METHODS: Fifty-six human extracted single root teeth were used in this study. Teeth were divided into four groups of 14 teeth each and prepared up to a #60 K-file size at 1 mm short of the apical foramen using a step-back technique. Argon laser at the wavelength of 470 nm and at the output of 0.3 W was irradiated at apical stop for 1, 2, or 3 seconds at the continuous mode. In each group, ten teeth for the microleakage study were obturated and immersed in rhodamine B solution for 48 hours at 37 degrees C, and the others were used for the observation by scanning electron microscopy (SEM). All teeth were bisected longitudinally and observed by stereoscopy or SEM. RESULTS: The apical leakage degree after laser treatment and obturation was reduced compared to that in the control, but not significantly (p > 0.05). However, debris and smear layer in the laser-treated groups were removed from apical stop even at low energy density. CONCLUSIONS: These results suggest that apical leakage after argon laser treatment is not reduced significantly, but that argon laser is useful for removing debris and smear layer from root canals.
OBJECTIVE: This study was performed to compare the apical leakage degree after laser treatment and obturation with that without laser treatment, and to evaluate the efficiency of argon laser irradiation in removing debris and smear layer from the prepared root canal walls in vitro. SUMMARY BACKGROUND DATA: There has been no report of laser effect on apical leakage after laser treatment and obturation. METHODS: Fifty-six human extracted single root teeth were used in this study. Teeth were divided into four groups of 14 teeth each and prepared up to a #60 K-file size at 1 mm short of the apical foramen using a step-back technique. Argon laser at the wavelength of 470 nm and at the output of 0.3 W was irradiated at apical stop for 1, 2, or 3 seconds at the continuous mode. In each group, ten teeth for the microleakage study were obturated and immersed in rhodamine B solution for 48 hours at 37 degrees C, and the others were used for the observation by scanning electron microscopy (SEM). All teeth were bisected longitudinally and observed by stereoscopy or SEM. RESULTS: The apical leakage degree after laser treatment and obturation was reduced compared to that in the control, but not significantly (p > 0.05). However, debris and smear layer in the laser-treated groups were removed from apical stop even at low energy density. CONCLUSIONS: These results suggest that apical leakage after argon laser treatment is not reduced significantly, but that argon laser is useful for removing debris and smear layer from root canals.