Antibiofilm Efficacy of Positively Charged Imidazolium-Based Silver Nanoparticles in Enterococcus faecalis Using Quantitative Real-Time PCR

Abstract

Background: Nanoparticles are made by different methodologies, which can affect the particle's features. Recently, imidazoliumcoated silver nanoparticles with a positive surface charge (PC Im-based AgNPs) have revealed favorable results as a root canal disinfectant. However, the antibacterial potency of these particles against biofilm form of Enterococcus faecalis, as the most resistant organism to eliminate in endodontic treatment, has not been investigated. It can be noted that removing this microorganism is associated with extremely effective disinfection. Objectives: This study investigated the antibacterial efficacy of PC Im-based AgNPs at 5.7 × 10-8 mol L-1 in comparison with 2.5% sodium hypochlorite (NaOCl) and 2% chlorhexidine as the two broadly used endodontic irrigation solutions against biofilm E. faecalis using quantitative real-time polymerase chain reaction. Methods: In total, 48 premolar teeth with a single root were infected with E. faecalis and then prepared with ProTaper rotary instruments. The samples were randomly allocated into 4 groups of 12 samples. Sterile saline, PC Im-based AgNPs, NaOCl, and chlorhexidine were used as irrigants. Sampling the root canals was implemented with paper points and Gates-Glidden drills. The reduction in E. faecalis counts was calculated and statistically analyzed by means of the Kruskal-Wallis and Mann-Whitney U tests. Results: Irrigation with PC Im-based AgNPs or NaOCl was significantly more effective in bacterial count reduction compared to irrigation with chlorhexidine or sterile saline (P < 0.05). There was no significant difference between PC Im-based AgNPs and NaOCl irrigants when either Gates-Glidden drills (P = 0.751) or paper points (P = 0.488) were employed. Chlorhexidine was significantly less efficient than PC Im-based AgNPs and NaOCl solutions (P < 0.001); however, it was significantly better than sterile saline in both sampling approaches (P > 0.001). Conclusions: The PC Im-based AgNP solution revealed promising results as a root canal irrigant. This solution at 5.7 × 10-8 mol L-1 was effectively able to eliminate biofilm E. faecalis and this was not significantly different from that of 2.5% NaOCl.

Antimicrobial peptide GH12 as root canal irrigant inhibits biofilm and virulence of Enterococcus faecalis

“…To better investigate the chemical disinfecting ability of the tested irrigants, the contaminated root canals were only treated by passive irrigation without mechanical debridement to avoid additional variable, which could be different from the clinical situation. The present study revealed that 1% NaOCl had a powerful antibacterial effect against intracanal E. faecalis biofilm, which is in accordance with the results of previous studies (Del Carpio‐Perochena et al 2011, Guerreiro‐Tanomaru et al 2014, Nabavizadeh et al 2017, Bolhari et al 2018, Rodrigues et al 2018). Extracellular polysaccharide matrix secreted by bacteria in biofilms could prevent AMPs penetration and requires a longer time of interaction to eliminate biofilm (Mai et al 2017).…”

Molecular Mechanisms of Bacterial Resistance to Metal and Metal Oxide Nanoparticles

“…The nanoparticles may have a positive, negative or neutral charge on their surface. The interaction of these three types of charge with the electric charge present on the surfaces of the bacteria in some cases seems to be the most important factor that determines the antimicrobial activity of the nanoparticles [24]. For example, Abbaszadegan et al tested the antimicrobial activity of silver nanoparticles with a positive, negative, and neutral charge on Gram-positive ( Streptococcus pyogenes, Streptococcus mutants, and Staphylococcus aureus ) and Gram-negative ( Proteus vulgaris and Escherichia coli ) species.…”

Application of Antimicrobial Nanoparticles in Dentistry

“…Long-term or secondary dental caries may lead to pulpitis and apical periodontitis which are mainly caused by bacteria and their products. Enterococcus faecalis ( E. faecalis ) is mainly responsible for reinfections after root canal therapy [43,44,45]. Complex root canal anatomy makes the complete microbial cleanup particularly difficult, even with a thorough root canal preparation and filling [46,47].…”

“…The application of NPs has attracted researchers’ attention [43,48,49,50,51]. Biosynthesized AgNPs had an antimicrobial ability against E. faecalis [52,53,54].…”