Rapid Kill—Novel Endodontic Sealer and Enterococcus faecalis

Abstract

With growing concern over bacterial resistance, the identification of new antimicrobial means is paramount. In the oral cavity microorganisms are essential to the development of periradicular diseases and are the major causative factors associated with endodontic treatment failure. As quaternary ammonium compounds have the ability to kill a wide array of bacteria through electrostatic interactions with multiple anionic targets on the bacterial surface, it is likely that they can overcome bacterial resistance. Melding these ideas, we investigated the potency of a novel endodontic sealer in limiting Enterococcus faecalis growth. We used a polyethyleneimine scaffold to synthesize nano-sized particles, optimized for incorporation into an epoxy-based endodontic sealer. The novel endodontic sealer was tested for its antimicrobial efficacy and evaluated for biocompatibility and physical eligibility. Our results show that the novel sealer foundation affixes the nanoparticles, achieving surface bactericidal properties, but at the same time impeding nanoparticle penetration into eukaryotic cells and thereby mitigating a possible toxic effect. Moreover, adequate physical properties are maintained. The nanosized quaternary amine particles interact within minutes with bacteria, triggering cell death across wide pH values. Throughout this study we demonstrate a new antibacterial perspective for endodontic sealers; a novel antibacterial, effective and safe antimicrobial means.

Lethal bacterial trap: Cationic surface for endodontic sealing

“…21,22 To extend our knowledge of the effect these quaternary ammonium compounds have on bacteria, and based on the published theories, we decided to evaluate the membrane effect these surfaces would have on bacteria. To this end, we developed a new testing method ( Fig.…”

“…FTIR analysis showed no detectable release of the QPEI nanoparticles from the modified sealer into the surroundings (data not shown). The spectra were recorded and studied in the wavenumber range 500-4000 cm 21 , with no QPEI detected at characteristic values (wavenumbers for quaternary ammonium cations: 910-970 cm 21 , for amines-3200-3700 cm 21 , and for alkyls and alkanes-1400-1500 cm 21 and 2700-3200 cm 21 , respectively).…”

“…19 Insoluble antibacterial quaternary ammonium polyethyleneimine (QPEI) nanoparticles have proved to have potent and long-lasting antibacterial surface properties both in vitro and in vivo. [20][21][22][23] The antibacterial mechanism of the quaternary ammonium compounds is not fully understood and is mostly hypothetical. It was suggested that ammonium compounds are adsorbed and penetrate through the bacterial cell wall, merge with the protein layer and analogous lipid layer, and subsequently block the normal exchange of ions and substances, leading to leakage of intracellular contents, and cell death.…”

Novel Bioactive and Therapeutic Root Canal Sealers with Antibacterial and Remineralization Properties

“…These antibacterial quaternary ammonium-based nanoparticles were previously incorporated into various dental resins that were able to inhibit biofilm formation both in vitro and in vivo [64,65]. Beyth et al used a polyethyleneimine scaffold to synthesize quaternary ammonium-based nano-sized particles (QPEI) that were incorporated into an epoxy-based endodontic sealer "RCS" [66]. The authors were able to affix the nanoparticles within the sealer to prevent their release and depletion over time [66].…”

“…Beyth et al used a polyethyleneimine scaffold to synthesize quaternary ammonium-based nano-sized particles (QPEI) that were incorporated into an epoxy-based endodontic sealer "RCS" [66]. The authors were able to affix the nanoparticles within the sealer to prevent their release and depletion over time [66]. When tested against E. faecalis, incorporating 1.5% QPEI nanoparticles significantly reduced the number of residual viable bacteria by 6 logs when compared to the unmodified RCS sealer [66].…”