The Photothermal Effect of 940nm Diode Laser on Enterococcus Faecalis Biofilm in Infected Root Canal

Background: The complete eradication of root canal pathogens (especially E. faecalis) is still dilemma for endodontists, however with the advanced laser technology newer disinfection protocols proposed to be effective for routine endodontic treatment. Aim: The aim behind this study is to test the efficiency of 940nm diode laser in destroying E. faecalis biofilm with/without the combination of NaoCl within root canals. Materials and methods: Forty extracted permanent single-rooted teeth were prepared, autoclaved and inoculated with E. faecalis culture then incubated for two weeks. After the incubation period, the specimens divided randomly in 4 groups; group A (n=10) control group, group B (n=10) irradiated with laser, group C (n=10) treated with NaoCl, and group D (n=10) treated with combination of NaoCl and laser radiation. Bacterial sampling done by inserting paper points inside the canals then plated on blood agar media to count CFU. Results: Dunnett's T3 test revealed highly significant difference among the groups (p=0.000, for groups C&D p=0.02) with exception for that between groups A and B which was significant difference (p=0.013). However, the combination protocol yielded the highest bacterial killing (95.5% CFU/ml reduction). Conclusion: The photothermal effect of the 940 nm wavelength has weak bactericidal effect on E. faecalis biofilm. However, when combined with 5.25% NaoCl a good disinfection results achieved with short irrigation time.