Efficacy of ultrasonic and Er:YAG laser activated EDTA irrigation in removing bacteria from ex vivo root canal system

Purpose Due to the limited effectiveness of irrigation to reduce the bacterial load inside root canals, the efficacy of activated irrigation techniques was evaluated. Methods Sixty endodontically prepared single-rooted human teeth were sterilized, infected with Enterococcus faecalis , and divided into six groups: (A) endodontic treatment positive control, (B) irrigation with EDTA 17%, (C) Er:YAG laser activated irrigation with tip 1 mm from working length, (D) Er:YAG laser to the coronal third, (E) ultrasonic irrigation applied 1 mm from working length, (F) US irrigation to the coronal third. Results The positive control group had significantly more bacteria than all other groups. EDTA irrigation had low efficiency. US irrigation 1 mm from the working length was significantly more effective than controls. Laser treatment to the coronal third was the most efficient. Conclusions Laser activated irrigation caused the greatest bacterial reductions.