New bone formation induced by surface strontium-modified ceramic bone graft substitute

Objectives: This study assessed the effect of surface strontium ion (Sr) modification on the osteogenic activity of an osteoconductive ceramic bone graft substitute with the hope of using the bone healing effect of Sr for potential application in periodontal and maxillofacial regenerative surgery. Materials and Methods: A simple wet chemical treatment was employed to deliver Sr to the surface of particulate porcine bone graft. The osteogenic activity of surface Sr-modified bone substitute was compared in vitro and in vivo with that of unmodified ceramic bone, other clinically available synthetic bone or osteoinductive allograft bone. Results: The resultant bone substitute showed the formation of Sr-containing microstructured surface layer along with the formation of additional nanostructures and displayed sustained Sr release. Sr modification promoted the osteogenic differentiation of bipotential ST2 stem cells. Sr-modified bone substitute increased the amount of newly formed bone at early healing period in calvarial defect of rabbits. Conclusions: These results suggest that the surface Sr modification by wet chemical treatment is a promising approach to enhance the early bone healing capacity of osteoconductive ceramic bone substitutes.