Double-layered acrylic resin denture base with nanoparticle additions: An in vitro study

Abstract

Statement of problem: Whether the addition of different antifungal nanoparticles to denture base materials may affect physical or esthetic properties of the resulting nanocomposite is unclear. Purpose: The purpose of this in vitro study was to determine how a new method of adding antifungal nanofiller affects the properties of the processed nanocomposite denture base material. Material and methods: Heat-polymerized acrylic resin specimens were prepared according to each test specification. Zirconium dioxide nanoparticles (ZrO2NPs) and silver nanoparticles (AgNPs) were added in 0.5, 1.0, and 1.5% of acrylic resin powder. The specimens were divided into 2 groups according to the acrylic resin packing method: 1 layer packed conventionally in one step and 2 layers packed in 2 steps, first with unmodified acrylic resin and then by a thin layer of modified acrylic resin before the final closure. The control group was made of unaltered acrylic resin in 1 step. Flexural strength (FS), translucency, and surface roughness (Ra) were measured. A microbial assay was performed by using the direct culture and slide count methods. Three-way ANOVA and Tukey post hoc tests were used to identify statistical differences among groups (α=.05). Results: The addition of ZrO2NPs and AgNPs in the 1- or 2-layer specimens reduced Candida albicans adhesion (P .05), while other AgNP groups exhibited increased surface roughness (P