Bone formation in TiO2 bone scaffolds in extraction sockets of minipigs

The osteoconductive capacity of TiO2 scaffolds was investigated by analysing the bone ingrowth into the scaffold structure following their placement into surgically modified extraction sockets in Gottingen minipigs. Non-critical size defects were used in order to ensure sufficient bone regeneration for the evaluation of bone ingrowth to the porous scaffold structure, and sham sites were used as positive control. Microcomputed tomographic analysis revealed 73.6 ± 11.1% of the available scaffold pore space to be occupied by newly formed bone tissue, and the volumetric bone mineral density of the regenerated bone was comparable to that of the native cortical bone. Furthermore, histological evidence of vascularization and the presence of bone lamellae surrounding some of the blood vessels were also observed within the inner regions of the scaffold, indicating that the highly interconnected pore structure of the TiO2 scaffolds supports unobstructed formation of viable bone tissue within the entire scaffold structure. In addition, bone tissue was found to be in direct contact with 50.0 ± 21.5% of the TiO2 struts, demonstrating the good biocompatibility and osteoconductivity of the scaffold material.