The Antibacterial Mechanism of Silver Nanoparticles and Its Application in Dentistry

Abstract

Nanotechnology has recently emerged as a rapidly growing field with numerous biomedical science applications. At the same time, silver has been adopted as an antimicrobial material and disinfectant that is relatively free of adverse effects. Silver nanoparticles possess a broad spectrum of antibacterial, antifungal and antiviral properties. Silver nanoparticles have the ability to penetrate bacterial cell walls, changing the structure of cell membranes and even resulting in cell death. Their efficacy is due not only to their nanoscale size but also to their large ratio of surface area to volume. They can increase the permeability of cell membranes, produce reactive oxygen species, and interrupt replication of deoxyribonucleic acid by releasing silver ions. Researchers have studied silver nanoparticles as antimicrobial agents in dentistry. For instance, silver nanoparticles can be incorporated into acrylic resins for fabrication of removable dentures in prosthetic treatment, composite resin in restorative treatment, irrigating solution and obturation material in endodontic treatment, adhesive materials in orthodontic treatment, membrane for guided tissue regeneration in periodontal treatment, and titanium coating in dental implant treatment. Although not all authorities have acknowledged the safety of silver nanoparticles, no systemic toxicity of ingested silver nanoparticles has been reported. A broad concern is their potential hazard if they are released into the environment. However, the interaction of nanoparticles with toxic materials and organic compounds can either increase or reduce their toxicity. This paper provides an overview of the antibacterial use of silver nanoparticles in dentistry, highlighting their antibacterial mechanism, potential applications and safety in clinical treatment.

Keywords: antibacterial; dentistry; nanoparticles; nanotechnology; silver.

Figure 1

The antibacterial actions of silver nanoparticles (AgNPs). 1) Disruption of cell wall and cytoplasmic membrane: silver ions (Ag+) released by silver nanoparticles adhere to or pass through cell wall and cytoplasmic membrane. 2) Denaturation of ribosomes: silver ions denature ribosomes and inhibit protein synthesis. 3) Interruption of adenosine triphosphate (ATP) production: ATP production is terminated because silver ions deactivate respiratory enzyme on cytoplasmic membrane. 4) Membrane disruption by reactive oxygen species: reactive oxygen species produced by the broken electron transport chain can cause membrane disruption. 5) Interference of deoxyribonucleic acid (DNA) replication: silver and reactive oxygen species bind to deoxyribonucleic acid and prevent its replication and cell multiplication. 6) Denaturation of membrane: silver nanoparticles accumulate in the pits of cell wall and cause membrane denaturation. 7) Perforation of membrane: silver nanoparticles directly move across cytoplasmic membrane, which can release organelles from cell.

Figure 2

The antibacterial application of silver nanoparticles in dentistry.