In Vitro Evaluation of a Bioactive Glass Coating for Titanium

Objectives: The aim of this study was to evaluate a new nanostructured titanium surface coated with bioactive glass.
Methods: The surface roughness of three groups was evaluated by atomic force microscopy: sandblasting and acid etching commercially pure titanium (cpTi) and coated with bioactive glass heated at temperatures of 37^°C (BGTi37) or 600^°C (BGTi600). Osteogenic cells were cultured in contact or not (control) with discs of these three groups. Cell viability (MTT assay) and cell activity (alkaline phosphatase) were measured after 7 days of culture. The mineralization was assessed by alizarin red test after 14 days of culture. The osteoblasts morphology in contact with the three surfaces was assessed by Scanning Electron Microscopy after 7 and 14 days. The data were statistically analyzed (ANOVA, Tukey’s, p<0.05).
Results: The cpTi group (129.6nm) showed the highest average roughness, followed by BGTi600 group (91.85nm) but they were statistically similar. The BGTi37 group (74.51nm) showed the lowest surface roughness compared to the other two groups. Cell viability, cell activity and mineralization of BGTi600 group were significantly lower than the control group and cpTi. Cell viability, cell activity and mineralization in the other groups (BGTi37, cpTi and control) showed no significant differences. Osteoblasts in contact to cpTi surface showed a flat polygonal morphology with several cytoplasm processes. Cells in contact with the experimental surfaces (BGTi37 and BGTi600) presented more tapered morphology, notably in contact with the BGTI600 surface.

Conclusions: The bioactive glass coating reduced the surface roughness compared to cpTi. The BGTi600 surface showed cytotoxicity and lower cell activity and mineralization. Cell viability, cell activity and mineralization in contact with BGTi37 surface were similar to control and cpTi groups. Differences in cell morphology suggest that those in contact with the BGTi600 surface show lower cell activity as compared to those in contact with the cpTi and BGTi37 surfaces.