Abstract: Abstract: Objective To evaluate and compare the outcomes of Light-SpeedLSX systems in single-visit and two-visit root canal treatment of patients with chronic apical periodontitis after a 2-year follow-up. Methods 300 maxillary and mandibular teeth with chronic apical periodontitis were randomly assigned into two groups. While the teeth of patients in group A were obturated, those in group B were temporarily sealed and obturated one week later. All canals were enlarged with Light-speedLSX root canal instruments. The healing results were clinically and radiographically evaluated 2 years after the operation. Results Of the 300 treated teeth, 138 of 147 teeth (93.88%) in the A group were healed compared with 122 of 137teeth (89.05%) in the B group, curative effects of 5 cases (3.40%) in the A group were classified as uncertain compared with 9 cases (6.57%) in the B group, 4 cases (2.72%) in the A group and 6 cases (4.38%) in the B group were classified as not healed. Chi-square test was used to compare the success rate of the two groups. Statistical analysis of the healing results did not show any significant difference between the groups (P>0.05). Conclusion There was no statistically significant difference between the single-visit and two-visit root canal treatment in patients with chronic apical periodontits prepared by Light-speedLSX root canal instruments.

Key words: Light-SpeedLSX, root canal treatment, chronic apical periodontitis