Effects of argon laser irradiation with 38% Ag(NH₃)₂ F on the permeability of root canal wall dentin

抄録

Abstract : The effects of argon laser irradiation on the permeability and structural changes of the root canal walls were investigated in vitro. Thirty extracted human single-rooted teeth were randomly assigned to three groups. Group 1 teeth were prepared conventionally but not lased. Group 2 teeth after conventional preparation, received four 15s duration laser exposures for total exposure of 60s/canal. Group 3 specimens, after conventional preparation, the root canal walls were treated by 38% Ag(NH₃)₂F for 10s, and then lased as the group 2 teeth. Laser parameters were set at 1 w, 5 Hz ; using simultaneous water coolant spray. The external surfaces of the teeth were sealed with nail vanish, and placed in 0.6% Rhodamin B solution for 48 hr. The teeth were then sectioned for study by stereomicroscope and SEM. Statistical analysis showed there was no significant difference of dye penetration between the groups (P<0.05). SEM examination showed that the argon laser-treated root surfaces (group 2) were partially recrystallized with open dentinal tubules and minor debris. The root canal surfaces of argon laser irradiation with 38% Ag(NH₃)₂F (group 3) revealed fusion and melting, numerous small particles, and generally free of smear layer ; open dentinal tubules in some melted parts were also visible.