A Clinical Study on the Effects of Pulsed Nd:YAG Laser Irradiation at Root Canals Immediately after Pulpectomy and Shaping

Objective: The effects of pulsed Nd:YAG laser irradiation for the treatment of root canals immediately after pulpectomy and shaping with regard to improvement of symptoms were evaluated clinically. Summary Background Data: The effects of pulsed Nd:YAG laser irradiation for the treatment of root canals were experimentally investigated using an animal model, but not under clinical conditions. Materials and Methods: Thirty-eight teeth from 29 patients were diagnosed as normal or irreversible pulpitis were used. After extirpation of pulp and shaping using a step-back technique and cleansing with 5% sodium hypochlorite (NaOCl) and 3% hydrogen peroxide (H₂O₂), laser irradiation was applied at 1 W and 15 pps for 1 second in 23 teeth (laser-treated group). Root canals were then obturated with gutta-percha points and sealer by the lateral condensation method. The condition of the obturations was confirmed radiographically. The control teeth were treated in the same way, but without laser irradiation. Occurrence of spontaneous pain was recorded 1 day after treatment and occurrence of percussion pain was recorded 1, 2, and 3 weeks after treatment. Results: Effective ratio, which was the ratio of the number of "none" teeth to total teeth number in the laser-treated group, was higher than that in the control group, but there was no significant difference between 2 groups with regard to spontaneous and percussion pain (p > 0.05). Conclusion: These results suggest that the clinical application of pulsed Nd:YAG laser might be advantageous for the one-visit treatment of root canals immediately after pulpectomy shaping and to reduce postoperative pain.