Osteogenic capacity of mixed-acid and heat-treated titanium mesh prepared by a selective laser melting technique.

The practical use of additive manufacturing to create artificial bone as a material for repairing complex bone defects is currently attracting attention. In this study, we compared the osteogenic capacity of materials composited by the method developed by Kokubo of treating 3D-printed titanium (Ti) mesh with a mixture of HSO and HCl and heating (mixed-acid and heat treatment) with that of materials subjected to conventional chemical treatment. Ti plates treated with this method have been found to promote highly active bone formation on their surface when inserted into rabbit tibial bone defects. No previous study has compared this method with other surface treatment methods. In this study, we used histological and other observations to compare the bone formation process in bone defects when Ti meshes prepared by the selective laser melting technique (SLM) and treated either with mixed acids and heat or with conventional chemical Ti surface treatments were implanted in a rat calvarial bone defect model. We found that both micro-computed tomography and observations of undecalcified ground sections showed that the best bone formation was observed in rats implanted with mesh treated with mixed acids and heat. Our results suggest that mixed-acid and heat-treated Ti mesh prepared by SLM may have a high osteogenic capacity in bone defects.