In vitro and in vivo evaluation of a macro porous β-TCP granule-shaped bone substitute fabricated by the fibrous monolithic process.

In this study, a new porous beta-tricalcium phosphate (β-TCP) granule was fabricated using the fibrous monolithic (FM) process and its in vitro biocompatibility and in vivo bone formation were evaluated. SEM micrograph images showed that MG-63 cells attached to the surfaces of the implant and were well proliferated. Cellular viability was as high as 75% in a50% extract dilution solution. cDNA micro array analysis was also carried out. In this analysis, we found a total of 12 up-regulated and 25 down-regulated genes. Four rabbits were used in the in vivo experiments. 3D micro-CT images showed that the formation of new bone was almost three times greater than that of normal trabecular bone (BV/TV). The histomorphometric results correlated with the micro-CT findings; a greater amount of new bone formation and osteoblast lineage along with osteocytes were observed in the implanted animals. Also x-ray radiographic and 2D micro-CT images were taken to demonstrate the superior biodegradability of the porous granule. As biodegradation occurred along with bone formation, 6 months after implantation, the porous granule structure was not distinguishable separately from that of the trabecular bone.