Antibacterial amorphous calcium phosphate nanocomposites with a quaternary ammonium dimethacrylate and silver nanoparticles

Abstract

Objectives Calcium and phosphate ion-releasing resin composites are promising for remineralization. However, there has been no report on incorporating antibacterial agents to these composites. The objective of this study was to develop antibacterial and mechanically-strong nanocomposites incorporating a quaternary ammonium dimethacrylate (QADM), nanoparticles of silver (NAg), and nanoparticles of amorphous calcium phosphate (NACP). Methods The QADM, bis(2-methacryloyloxyethyl) dimethylammonium bromide (ionic dimethacrylate-1), was synthesized from 2-(N,N-dimethylamino)ethyl methacrylate and 2-bromoethyl methacrylate. Ng was synthesized by dissolving Ag 2-ethylhexanoate salt in 2-(tertbutylamino)ethyl methacrylate. Mechanical properties were measured in three-point flexure with bars of 2×2×25 mm (n = 6). Composite disks (diameter = 9 mm, thickness = 2 mm) were inoculated with Streptococcus mutans. The metabolic activity and lactic acid production of biofilms were measured (n = 6). Two commercial composites were used as controls. Results Flexural strength and elastic modulus of NACP+QADM, NACP+NAg, and NACP+QADM+NAg matched those of commercial composites with no antibacterial property (p > 0.1). The NACP+QADM+NAg composite decreased the titer counts of adherent S. mutans biofilms by an order of magnitude, compared to the commercial composites (p < 0.05). The metabolic activity and lactic acid production of biofilms on NACP+QADM+NAg composite were much less than those on commercial composites (p < 0.05). Combining QADM and NAg rendered the nanocomposite more strongly antibacterial than either agent alone (p < 0.05). Significance QADM and NAg were incorporated into calcium phosphate composite for the first time. NACP+QADM+NAg was strongly-antibacterial and greatly reduced the titer counts, metabolic activity, and acid production of S. mutans biofilms, while possessing mechanical properties similar to commercial composites. These nanocomposites are promising to have the double benefits of remineralization and antibacterial capabilities to inhibit dental caries.

Micromorphological cellular responses of MC3T3-E1 and RAW264.7 after exposure to water-dispersible silver nanoparticles stabilized by metal-carbon σ-bonds

“…Recent studies have shown quaternary ammonium dimethacrylate and Ag-NPs to be effective as primers for dental adhesives because of their antibacterial properties and bond strength 8,20) . The main purpose of surface modification of Ag-NPs (e.g.…”

Antibacterial/Antiviral Property and Mechanism of Dual-Functional Quaternized Pyridinium-type Copolymer

“…It has been proven that quaternary ammonium salt (QAS) moieties can affect the viability of Gram-positive and Gram-negative bacteria due to positive charges that exert a strong electrostatic interaction with negatively charged bacteria [25][26][27]. Therefore, the positive charge density of QAS antimicrobial agents plays a key role in their antimicrobial performance.…”

Quaternary ammonium compounds in dental restorative materials

“…In 2006, a research developed by Beyth et al 24) reported that 1 wt% quaternary ammonium polyethyleneimine (QPEI) nanoparticles immobilized into composite or fluid resin had strong antimicrobial activity upon contact without leach-out of the nanoparticles and compromising in mechanical properties. Cheng et al [25][26][27] performed studies incorporating of nanoparticles of amorphous calcium phosphate (NACP), quaternary ammonium dimethacrylate (QADM), and nanoparticles of silver (NAg) into composite resins. The results had shown that modified resins greatly decreased biofilm metabolic activity, colony-forming unit (CFU), and lactic acid with strong and durable antimicrobial properties and remineralization, while matching the load-bearing capability of commercial composites without antimicrobial properties.…”

“…It has been shown that there is microleakage on restoration margins, and these gaps can be colonized by oral bacteria, thus resulting in secondary caries, which makes the restoration replacement necessary 22,23) . In order to prevent or diminish biofilm accumulation over composite and in the restorations margins, and also to improve the durability of prostheses, antimicrobial restorative materials have been developed, especially through the incorporation of quaternary ammonium to composite resins [24][25][26][27][28][29][30][31][32] . In 2006, a research developed by Beyth et al 24) reported that 1 wt% quaternary ammonium polyethyleneimine (QPEI) nanoparticles immobilized into composite or fluid resin had strong antimicrobial activity upon contact without leach-out of the nanoparticles and compromising in mechanical properties.…”