(PR061) Antibacterial Effect of Cannabinoids on Bacteria Associated with Persistent Endodontic Infections

Objective - Cannabinoids have been shown to have antibacterial applications in medicine. With limitations of endodontic medicaments, and increase of bacterial resistance, additional strategies should be investigated. The aim of this study is to test the antibacterial efficacy of cannabinoids on bacteria found in persistent endodontic infections: Enterococcus faecalis, Streptococcus mutans, and Fusobacterium nucleatum. Methods – Planktonic bacteria were exposed to: negative control, positive control (3% sodium hypochlorite), and experimental groups (Cannabidiol (CBD), Cannabinol (CBN), and tetrahydrocannabinol (THC)). Minimum inhibitory concentration (MIC) was measured using TECAN. Minimum bactericidal concentration (MBC) was investigated. Biofilms were cultured and treated with cannabinoids. Crystal violet and live/dead analysis were performed to assess biofilm degradation and inhibition respectively. ANOVA was used for statistical analysis. Results – For E. faecalis, the MIC of all three cannabinoids was 4 µg/mL. The MBC for CBD and CBN was 16 µg/mL and for THC was 64 µg/mL. Live/dead analysis showed increased cannabinoid concentration reduced biofilm viability. Approximately 50% of biofilm was degraded with 32 µg/mL of all cannabinoids. For S. mutans, the MIC of CBD and CBN was 2 µg/mL and 1 µg/mL for THC. There was no MBC found in all concentrations tested. An increase in cannabinoid concentration reduced biofilm viability. The S. mutans biofilm was not degraded by any tested concentration. Conclusion – CBD, CBN, and THC have inhibitory effects on E. faecalis and S. mutans in both the planktonic and biofilm states. Experiments to assess the effects of cannabinoids on F. nucleatum are ongoing.