Influence of silver nano-particles on monomer elution from light-cured composites

Objectives. Silver containing materials have been used for years as antimicrobial materials. Silver particles were also added to experimental dental composites to reduce caries. The aim of our study was to show whether silver nanoparticles can lead to higher amounts of elutable substances. Methods. 0.0125, 0.025, 0.05, 0.1 and 0.3% by weight silver nanoparticles were added to the commercial composite Tetric Flow (R). After light curing of the specimen, they were stored up to 7 days in methanol. The eluate was analyzed by gas chromatography/mass spectrometry. Results. Compared to controls more camphorquinone (CQ), ethoxylated bisphenol-A-dimethacrylate (BisEMA) and triethylene glycol dimethacrylate (TEGDMA) will be eluted when silver nanoparticles were added to the composite. Twenty-four hours after the beginning of the experiment 132 mu mol/l of CQ, 33.9 mu mol/l BisEMA and 4.5 mmol/l TEGDMA were found in the eluate of the specimens containing 0.3% Ag. Significance. Silver nanoparticles may influence the polymerization process in dental materials and lead to an increase in elutable substances. Four possible mechanisms of interaction are discussed: (1) reflection and scattering of the photons, (2) absorption of photons, (3) electron transfer from or to the silver nanoparticles and (4) formation of complexes with Ag+-ions. (C) 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.