Cytocompatible antifungal acrylic resin containing silver nanoparticles for dentures

Abstract

Background: Inhibition of Candida albicans on denture resins could play a significant role in preventing the development of denture stomatitis. The safety of a new dental material with antifungal properties was analyzed in this work.

Methods: Poly(methyl methacrylate) [PMMA] discs and PMMA-silver nanoparticle discs were formulated, with the commercial acrylic resin, Nature-Cryl™, used as a control. Silver nanoparticles were synthesized and characterized by ultraviolet-visible spectroscopy, dispersive Raman spectroscopy, and transmission electron microscopy. The antifungal effect was assessed using a luminescent microbial cell viability assay. Biocompatibility tests were carried out using NIH-3T3 mouse embryonic fibroblasts and a Jurkat human lymphocyte cell line. Cells were cultured for 24 or 72 hours in the presence or absence of the polymer formulations and analyzed using three different tests, ie, cellular viability by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and cell proliferation by enzyme-linked immunosorbent assay BrdU, and genomic DNA damage (Comet assay). Finally, the samples were evaluated mechanically, and the polymer-bearing silver nanoparticles were analyzed microscopically to evaluate dispersion of the nanoparticles.

Results: The results show that PMMA-silver nanoparticle discs significantly reduce adherence of C. albicans and do not affect metabolism or proliferation. They also appear not to cause genotoxic damage to cells.

Conclusion: The present work has developed a new biocompatible antifungal PMMA denture base material.

Keywords: Candida albicans; antifungal effect; cytotoxicity; dental polymers; denture bases; genotoxicity.

Figure 1

Silver nanoparticle analysis. (A) Ultraviolet spectrum showing the presence of plasmon at 410 nm. (B) Raman dispersive spectra indicating characteristic peaks of silver nanoparticles at 1410 cm⁻¹ and 1620 cm⁻¹. (C) Transmission electron micrograph showing spherically shaped nanoparticles and particles measuring 10–20 nm.

Figure 2

Biocompatibility in NIH-3T3 mouse cells. (A) MTT assay performed in PMMA and Nature Cryl™ groups showed no significant statistical differences at 24 hours and 72 hours. (B) Cells were exposed to PMMA formulations for 24 hours and proliferation was analyzed using BrdU antibodies. Note: No significant differences were found between the groups according to one-way analysis of variance (P ≤ 0.05). Abbreviation: PMMA, poly(methyl methacrylate).

Figure 3

Genotoxic assay in Jurkat human cells. Comet assay images showing formation of tails when genotoxic cell damage was caused by contact with the acrylic materials. Images showing round cells indicate that the genetic DNA material is intact and that the cell nucleus has not been damaged. Jurkat cells exposed to direct ultraviolet irradiation for 5 minutes were used as a positive control. (A) Representative photographs of single-cell gel electrophoresis ethidium bromide-stained nuclei. (B) Corresponding quantitative analysis of positive cells with DNA damage (P < 0.05).

Figure 4

Scanning electron micrograph of PMMA-silver nanoparticles showing a homogeneous silver nanoparticle distribution in the PMMA matrix. Abbreviation: PMMA, poly(methyl methacrylate).