Disinfection of root canals using Er:YAG laser at different frequencies.

摘要

OBJECTIVE: This study evaluated, in vitro, the degree of disinfection of the Er:YAG laser in root canals contaminated with Bacillus subtilis, Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, and Candida albicans, for 28 days. METHODS: Forty-six single-rooted human teeth were divided into five groups of eight teeth each; three teeth were used as negative controls and three as positive controls. After contamination, the root canals were prepared mechanically. Three groups were irradiated with Er:YAG laser at 100 mJ, varying the frequency (7, 10, and 16 Hz). Two groups were irrigated with 1.0 and 2.5 NaOCl solution. After treatment, two sterilized paper cones were placed in the root canals for 5 min. One cone was transferred to 2.0 mL of Letheen broth culture medium, incubated at 37 degrees C for 48 h, and then 0.1 mL of that solution was placed in 2.0 mL of brain heart infusion for 48 h to determine microbial growth. The other cone was transferred to a test pipette with peptone andwater for serial dilution and spread in Mueller Hinton medium. After 24 h of incubation, the colony-forming units (CFUs) were counted. RESULTS: There was a microbial reduction of 85.33 for the group irradiated with Er:YAG laser at 100 mJ/7 Hz, 74.58 at 100 mJ/10 Hz, and 89.50 at 100 mJ/16 Hz. For the groups irrigated with 1.0 and 2.5 NaOCl solution, 83.15 and 84.46 values of microbial reduction were obtained respectively. CONCLUSION: All the groups showed statistically similar results (p > 0.05). No method totally eliminated microorganisms.