Antibacterial potential of nano-particulate intracanal medications on a mature E. faecalis biofilm in an ex-vivo model

Aim: To investigate and compare the antibacterial and antibiofilm activity of Chlorhexidine Digluconate functionalized Hydroxyapatite Nanoparticles and silver Nanoparticles as intracanal medicaments on a mature E. faecalis biofilm model in root canals of extracted teeth. Methodology: Sixty-eight human maxillary central incisors were mechanically prepared, sterilized, infected with E. faecalis, and then incubated for 28 days under anaerobic conditions to develop a mature E. faecalis biofilm. Eight teeth were used to monitor biofilm formation and maturation over the incubation period with field emission scanning electron microscopy (Fe SEM), while the other 60 teeth were divided into two experimental groups (n=20) in which 2% chlorhexidine digluconate functionalized hydroxyapatite nanoparticles (Group A) and 0.02% silver nanoparticles (group B) were used as intra canal medications, and two control groups (n=10). The positive control group (Group C) was used to check for bacterial viability throughout the experiment, while the negative control group (Group D) was used to check for sterility of the procedures. Finally, bacterial samples were collected and analyzed quantitively by culture counts and qualitatively by real time PCR (RTQ-PCR). Results: RTQ-PCR detected E. faecalis DNA in all groups except for the negative control group. The mean values of E. faecalis DNA detected in groups A, B and C were 99.6 ng/mL,  67.1 ng/mL , 2797.4 ng/mL respectively. Statistical analysis of these results showed that both treatment groups presented statistically significantly lower mean values of E. faecalis DNA quantities compared to the positive control group. However, there was no statistically significant difference between them (P<.05). Conclusions: Chlorhexidine Digluconate functionalized Hydroxyapatite Nanoparticles and silver nanoparticles demonstrated an effective antimicrobial activity against mature E. faecalis biofilms.