Cytotoxicity of silver tungstate (±-Ag2WO4) in solution and after coating an acrylic resin denture base: analysis of cellular metabolism

Abstract

In dental prosthetics and medical devices, differen tbiomaterials may be coated with nanoparticles to improve their biological properties, particularly adhesion and proliferation of micro-organisms. However, the biocompatibility of different biomaterials coated with nanoparticles has not been evaluated and, therefore, studies are needed in order to improve their performance in vivo. Thus, the aim of this study is to evaluate the cytotoxicity of silver tungstate (±-Ag2WO4) and an acrylic resin for denture base coated with silver in order to make them viable for clinical use in preventing biofilm. For this, specimens (14 mm in diameter and 1.2 mm thick) of an acrylic base resin (VipiWave; VIPI Ind. e Com. Exp. e Imp. de Prod. Odont. Ltda., Pirassununga, SP, Brasil) will be prepared and divided in two groups (n = 6): uncoated (control) and coated ±-Ag2WO4. To analyze the cytotoxic effect of substances released by specimens, extracts of water-soluble substances of the samples will be obtained. For this purpose, three samples of each experimental group will be placed into test tubes with 3 ml of DMEM culture media and incubated for 24 hours. To perform the cytotoxicity test, 100 µl of the suspension consisted of 1,0 x 105cells/ml are placed in eachcompartment of a plate with 96 orifices, incubated in incubator with 5% CO2 at 37° C for 24 hours. After this incubation period, the culture media will be discarded, leaving the cells attached on the bottom plate and 50 µl of fresh culture media are placed in each orifice of the plate along with 50 µl of extract containing the substances released by the specimens, which will be incubated for 24 hours. After this period, cell proliferation will be analyzed using the MTT test and analysis of membrane integrity. The results of cellular metabolism of viable cells after contact with extracts of the studied materials will be subjected to appropriat estatistical method and the level of significance of 5% will be selected (± = 0,05). Futhermore, the results for each test will be compared with the negative control and treatments in the different experimental groups will be classified according to the cytotoxic effect scores from 0 to 3.