Antibacterial effect of composite resin foundation material incorporating quaternary ammonium polyethyleneimine nanoparticles

Abstract

Statement of problem: As caries is the most frequent cause of the failure of composite resin-based restorations, composite resins with antibacterial properties are desirable. However, whether quaternary ammonium polyethyleneimine nanoparticles can be effectively incorporated is unknown.

Purpose: The purpose of this in vitro study was to evaluate the antibacterial activity against Streptococcus mutans and Actinomyces viscosus of a foundation material incorporating quaternary ammonium polyethyleneimine (QPEI) nanoparticles.

Material and methods: QPEI antimicrobial nanoparticles were incorporated in a commercially available foundation material (Q Core; BJM Laboratories Ltd) at 1% wt/wt. Antibacterial efficacy against S mutans (10⁶ colony-forming units [CFU]/mL) and A viscosus (10⁶ CFU/mL) was examined by the direct contact test (DCT), and the agar diffusion test (ADT) with and without surface polishing. Bacterial outgrowth was recorded with a spectrophotometer.

Results: Growth of S mutans and A viscosus was inhibited, showing a decrease by 6 orders of magnitude in bacterial viability in specimens incorporating the nanoparticles, even after polishing the foundation material (P<.05). Growth inhibition was not observed in specimens without nanoparticles.

Conclusions: Antibacterial properties can be achieved in a commercially available foundation material by incorporating polycationic antibacterial nanoparticles. This antibacterial effect did not diminish after surface polishing.