Hydroxyapatite decreases cytotoxicity of a glass ionomer cement by calcium fluoride uptake in vitro.

BACKGROUND: Glass ionomer cements (GICs) are widely used in dentistry because of their remineralizing and cariostatic potential induced by fluoride. In vitro studies have reported cell toxicity triggered by GICs; however, the influence of hydroxyapatite (HAp) must be considered. The aim of this study was to evaluate the effect of HAp in decreasing the cytotoxicity of the GIC 3M Vitrebond in vitro. METHODS: Samples of 3M Vitrebond (powder, liquid and light-cured) were incubated in Dulbecco's modified Eagle's medium-Ham's F12 (DMEM-F12) for 24 hours at 37°C. Subsequently, the light-cured medium was treated with 100 mg/mL of HAp overnight. Toxicity of conditioned media diluted 1:2, 1:4, 1:8 and 1:20 was analyzed on human gingival fibroblasts (HGFs) using light microscopy and the fluorometric microculture cytotoxicity assay. The amounts of calcium fluoride (CaF2) were determined by the alizarin red S method. RESULTS: The exposure of HGFs to light-cured induced cell death and morphological changes such as chromatin condensation, pyknotic nuclei and cytoplasmic modifications. Exposure to light-cured treated with HAp, significantly increased cell viability leading to mostly spindle-shaped cells (p<0.001). The concentration of CaF2 released by the light-cured was 200 ppm, although, in the light-cured/HAp conditioned medium, this quantity decreased to 88 ppm (p<0.01). CONCLUSIONS: These data suggest that HAp plays a protective role, decreasing the cytotoxic effect of 3M Vitrebond induced by CaF2.

Antimicrobial and antibiofilm activities of MTA supplemented with bismuth lipophilic nanoparticles.

The objective of this work was to determine the antimicrobial and antibiofilm properties of mineral trioxide aggregate (MTA) supplemented with bismuth lipophilic nanoparticles (BisBAL NPs). The antimicrobial activity of the composite MTA-BisBAL NPs was determined by the disk diffusion assay, while antibiofilm activity was analyzed by fluorescence microscopy. The cytotoxicity of MTA-BisBAL NPs was determined on human gingival fibroblasts by optical microscopy and crystal violet staining. MTA-BisBAL NPs inhibited the growth of Enterococcus faecalis, Escherichia coli, and Candida albicans and also detached the biofilm of fluorescent E. faecalis after 24 h of treatment. The addition of BisBAL nanoparticles did not significantly modify the physical properties of MTA, and cytotoxicity was not observed when MTA-BisBAL NPs was added on human gingival fibroblasts. Altogether these results suggest that BisBAL nanoparticles provide antimicrobial and antibiofilm activities to MTA while it retained their biophysical properties without cause side effects on human gingival fibroblasts.