(PO44) Effectiveness of Micro/Nano Diamond Endodontic Irrigant Activated by Sonic and Ultrasonic Oscillation on Biofilm Removal

Abstract: Biofilm removal in infected root canals remains a persistent challenge. While studies have shown that sodium hypochlorite with sonic or ultrasonic agitation can reduce biofilms, a comprehensive method for complete removal is currently lacking. Our previous research demonstrated the antimicrobial effectiveness of 500 nm nano-diamonds at 10 mg/mL against Enterococcus faecalis, showcasing their ability to remove smear layers with sonic and ultrasonic agitation in a sodium hypochlorite solution. This study aims to investigate the effectiveness of a nano-diamond endodontic irrigant activated by sonic and ultrasonic oscillation on biofilm removal. Eighty single-rooted extracted premolars were shaped to ProTaper F2 with nickel-titanium rotary instruments and immersed in an Enterococcus faecalis bacterial culture for 21 days to form biofilms. The irrigant, consisting of 500 nm nano-diamonds mixed with sodium hypochlorite at 10 mg/mL, was agitated using either sonic or ultrasonic methods. Qualitative and quantitative analyses included colony-forming unit (CFU) counts, biofilm formation ability, bacterial biofilm metabolic activity testing, and scanning electron microscope observation. The preliminary results indicated that incorporating nano-diamonds into the irrigant (mixed with normal saline or sodium hypochlorite), combined with sonic and ultrasonic oscillation, significantly decreased CFU and biofilm formation compared to other control and no nano-diamond groups (p < .05). In conclusion, the use of sonic and ultrasonic agitation with a 500 nm nano-diamond 10 mg/mL irrigation solution appears to present a promising antibacterial alternative for biofilm removal in root canal treatment.