Evaluation of Antimicrobial Efficacy of UVC Radiation, Gaseous Ozone, and Liquid Chemicals Used for Disinfection of Silicone Dental Impression Materials.

Effective disinfection of dental impressions is an indispensable requirement for the safety of dental personnel and patients. The ideal method should be not only effective but also convenient, cheap, and environmentally friendly. This study aimed to reliably evaluate the efficacy of ultraviolet C (UVC) radiation, gaseous ozone, and commercial liquid chemicals used for silicone dental impressions disinfection. These methods were applied to two types of elastomeric impression materials: condensation silicones and addition silicones of various consistency (putty, medium, and light). The antimicrobial effectiveness against Pseudomonas aeruginosa, Staphylococcus aureus, and Candida albicans was evaluated in vitro by counting colony-forming units (CFU) on the surface of samples. The one-way ANOVA with a Tukey HSD test or the Kruskal-Wallis with a Dunn's test was performed. The results obtained revealed the efficacy of the proposed methods for disinfection of both C-silicones and A-silicones in most of the studied groups. Only one material (Panasil initial contact Light) was not effectively disinfected after UVC irradiation or ozone application. In conclusion, the potential of each disinfection method should be evaluated separately for each material. Moreover, in further research, the possible influence of the proposed methods on the physical properties of the impression materials should be thoroughly investigated.

Biological activity of quaternary ammonium salts and resistance of microorganisms to these compounds.

Quaternary ammonium salts (QASs) are ubiquitous in nature, being found in organisms ranging from microorganisms to vertebrates (e.g., glycine betaine, carnitine) where they have important cellular functions. QASs are also obtained by chemical synthesis. These compounds, due to their diverse chemical structure (e.g. monomeric QAS or gemini) and their biological properties, are widely used in medicine (as disinfectants, drugs, and DNA carriers), industry, environmental protection and agriculture (as preservatives, biocides, herbicides and fungicides). Discussed chemical compounds reduce the adhesion of microorganisms to various biotic and abiotic surfaces and cause the eradication of biofilms produced by pathogenic microorganisms. The properties of these chemicals depend on their chemical structure (length of the alkyl chain, linker and counterion), which has a direct impact on the physicochemical and biological activity of these compounds. QASs by incorporation into the membranes, inhibit the activity of proteins (H+-ATPase) and disrupt the transport of substances to the cell. Moreover, in the presence of QASs, changes in lipid composition (qualitative and quantitative) of plasma membrane are observed. The widespread use of disinfectants in commercial products can induce resistance in microorganisms to these surfactants and even to antibiotics. In this article we discuss the biological activity of QASs as cationic surfactants against microorganisms and their resistance to these compounds.

Polish Propolis-Chemical Composition and Biological Effects in Tongue Cancer Cells and Macrophages.

The purpose of this study was to compare the chemical composition and biological properties of Polish propolis. Ethanol, ethanol-hexane, hexane and hexane-ethanol extracts of propolis from three different regions of Poland were prepared. On the basis of the evaluation of their chemical composition as well as the extraction yield and free radical scavenging activity, the ethanol and hexane-ethanol extractions were proposed as the most effective methods. Subsequently, the biological properties of the extracts were evaluated to investigate the selectivity of an anticancer effect on tongue cancer cells in comparison to normal gingival fibroblasts. The obtained products demonstrated anticancer activity against tongue cancer cells. Additionally, when the lowest extract concentration (100 µg/mL) was applied, they were not cytotoxic to gingival fibroblasts. Finally, a possible anti-inflammatory potential of the prepared products was revealed, as reduced mitochondrial activity and proliferation of macrophages exposed to the extracts were observed. The results obtained indicate a potential of Polish propolis as a natural product with cancer-selective toxicity and anti-inflammatory effect. However, further studies are still needed to thoroughly explain the molecular mechanisms of its action and to obtain the promising health benefits of this versatile natural product.