An innovative quaternary ammonium methacrylate polymer can provide improved antimicrobial properties for a dental adhesive system

Abstract

A quaternary ammonium methacrylate polymer (QAMP) with antimicrobial potential was synthesized. The resulting product (QAMP) was characterized by FTIR spectroscopy, NMR spectroscopy, visible spectrophotometry, XRPD and TGA. The in vitro susceptibility tests against Streptococcus mutans of QAMP were investigated prior and after incorporation into a commercial adhesive system (Clearfil™ SE Bond). The release of quaternary ammonium compounds from the experimental adhesive system (Clearfil™ SE Bond + 5% QAMP) was performed during 1, 7, 14, 21 and 30 days. Spectroscopic data confirmed that QAMP was successfully obtained. Thermogravimetric analysis indicated that QAMP was heat stable. Prior incorporation into the adhesive system, QAMP revealed an inhibition halo of 18.33 ± 0.6 mm. By agar disk diffusion test, Clearfil™ SE Bond containing 5% QAMP presented an inhibition halo (16.67 ± 1.5 mm) similar to Clearfil™ Protect Bond (positive control, 17.00 ± 1.7, p = 0.815) and significantly higher than Clearfil™ SE Bond (negative control, 11.00 ± 1.0, p = 0.006). The minimum inhibitory/bactericidal concentrations for Clearfil™ SE Bond containing 5% QAMP were 20 μL mL(-1). The release of quaternary ammonium compounds from the experimental adhesive containing QAMP was very low (5.1%) when compared to Clearfil™ Protect Bond that released 47.2% of its quaternary ammonium monomer (MDPB) after 30 days. The QAMP can offer enhanced antimicrobial properties for self-etching adhesive systems.

Quaternary ammonium compounds in dental restorative materials

“…Generally speaking, however, with the increase of the amount of antibacterial agent, the mechanical properties and biocompatibility of the material will decrease. QACs belong to a kind of nonrelease antibacterial agent, and the antibacterial effect can be achieved when the dosage is relatively large 32,[44][45][46][47] . While the release antimicrobial agents can achieve better antibacterial effect at a low concentration, however, their extending antibacterial efficiency is low and they may be more toxic toward surrounding environments, the so-called "sudden release effect" [104][105][106][107] .…”

“…Meanwhile, 5 wt% DMADDM was incorporated into Clearfil SE Bond by Zhang et al It had been observed that adhesives containing DMADDM inhibited the growth, lactic acid production, and Exopolysaccharides (EPS) metabolism of S. mutans biofilm at different stages, with no adverse effect on its dentin adhesive bond strength 44,45) . Besides that, Pupo et al 46,47) performed a study incorporating of quaternary ammonium methacrylate polymer (QAMP) at 5% by mass to Clearfil SE Bond as experimental group, Clearfil SE Bond as negative control group, and Clearfil Protect Bond as positive control group. The results showed that experimental group demonstrated the minimum inhibitory /bactericidal concentration (MIC/MBC) values and an inhibition zone against Lactobacillus casei (L. casei) and Actinomyces naeslundii (A. naeslundii) similar to the positive control, and higher MIC/MBC values and smaller inhibition zone than the negative control for S. mutans, L. casei, and A. naeslundii, and that no statistically significant difference in the resin-dentin bond strength (μTBS) was observed between experimental and negative control groups immediately, after 6 months, or 12 months of water storage.…”

“…The antibacterial effect against two E. faecalis strains (ATCC and an endodontic isolate) were assessed, and results had shown that addition of QPEI nanoparticles improved the killing ability of PCS against biofilms of both E. faecalis strains and the effects of AH Plus on the biomass of biofilms from the ATCC strain. Moreover, there were no relevant changes in physicochemical and 95) quaternary ammonium polyethyleneimine QPEI unpolymerizable composite resin 24) , endodontic materials [89][90][91] quaternary ammonium dimethacrylate QADM/IMQ polymerizable composite resin [25][26][27]32) , adhesive system 42) 2-methacryloxylethyl dodecyl methyl ammonium bromide MAE-DB polymerizable composite resin 28,29) 2-methacryloxylethyl hexadecyl methyl ammonium bromide MAE-HB polymerizable composite resin 28,29) 2-Dimethyl-2-dodecyl-1-methacryloxyethyl ammonium iodine DDMAI polymerizable composite resin 30) quaternary ammonium methacrylate QAM polymerizable composite resin 31) , adhesive system 5,53,54) 2-methacryloyloxyethyl phosphorylcholine MPC polymerizable composite resin 33) dimethylaminododecyl methacrylate DMADDM polymerizable adhesive system [43][44][45] quaternary ammonium methacrylate polymer QAMP unpolymerizable adhesive system [46][47][48] methacryloxylethyl cetyl ammonium chloride DMAE-CB polymerizable adhesive system [49][50][51][52] benzalkonium chloride BAC unpolymerizable adhesive system [55][56][57] , glass ionomer cement 73,74) , endodontic materials 87) poly-2-methacry...…”

Effect on vascular permeability of a self-etching adhesive system containing an antimicrobial quaternary ammonium polymer QAMP into subcutaneous tissue of rats

“…This innovative product was then incorporated into self-etching adhesive systems and provided an enhanced antibacterial effect against Streptococcus mutans. 6 In addition, QAMP avoided the rapid release of quaternary ammonium molecules from the dental adhesive system in contrast to that observed for the commercial product containing MDPB due to its polymeric structure. 6 Despite great progress concerning new dental polymers, their use as dental products is still controversial due to some toxic effect on the cells of pulpo-dentine complex.…”

“…6 In addition, QAMP avoided the rapid release of quaternary ammonium molecules from the dental adhesive system in contrast to that observed for the commercial product containing MDPB due to its polymeric structure. 6 Despite great progress concerning new dental polymers, their use as dental products is still controversial due to some toxic effect on the cells of pulpo-dentine complex. In that sense, quaternary ammonium compounds can show cytotoxicity to human pulpal cells, which requires their use in low concentration to ensure clinical safety.…”