Avaliação do efeito de diferentes tipos de fios ortodônticos sobre a viabilidade celular e produção de óxido nítrico em células J774

Abstract

The oral environment is particularly favorable to metal biodegradation due to is ionic, thermal, microbiological, and enzymatic properties. Studies have shown that metal ions may be released from metallic materials as the result of corrosion. Other studies demonstrate that Nickel is a common component in many orthodontic materials and that an allergy to Nickel is commonly observed in the population. In addition to the traditional cytotoxicity tests, the study of nitric oxide cellular production stimulated by a specific material has shown to be a reliable tool for evaluating its cytotoxic potential. The present study was aimed at assessing cellular viability by MTT [3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl tetrazolium bromide] assay in a murine macrophage cell line J774 in the presence of 9 different orthodontics wires and quantify nitric oxide production by these cells. Evaluation of cell culture was undertaken in three time intervals: 24, 48 and 72 hours. The cellular viability in all groups was higher at the final time interval than at the initial time interval. This increase was statistically significant in the control group. In the material groups, the final mean of cellular viability at 72 hours showed no statistically significant difference when compared with the control group. NO production in all groups was higher at the final time interval than at the initial time interval. This increase was statistically significant in the control group. In the material groups, the final mean of NO production at 72 hours was only significant in group 8 (beta-Titanium) when compared with the control group. In a second step of the study, macrophages were activated with gamma interferon (IFN-) in order to stimulate a common condition of the human body in which these cytokines are produced and released with the presence of antigens. The means of the analysis of cell viability of murine macrophages activated with gamma interferon in the groups of orthodontic wires did not show statistically significant difference when compared to the mean of cells in the control group. The means of the analysis of NO production by the murine macrophages activated with gamma interferon in the groups of orthodontic wires did not show statistically significant difference when compared to the mean of cells in the control group.