Effect of Porosity of Titanium Web on Cortical Bone Response

Titanium fiber web (TW), which is produced by sintering intertwined thin titanium fibers, is non-degradable three-dimensional scaffold material graft substitutes. TW has sufficient stiffness and elasticity for role and is bone compatible and easy to handle during surgery. We aimed to evaluate the influence of the differences of porosities of TWs on bone formation inside the TWs. Three types of TWs with different volumetric porosity, 60%, 73% and 87%, with a fiber diameter of 50 mu m were used. The TW was height of 4 mm, width of 4mm and thickness of 2 mm. SEM views of TWs indicated that the mean pore size of the TW was approximately 100-150 mu m for 60% porosity TW, 200-250 mu m for 73% porosity TW and 300-350 mu m for 87% porosity TW. Each TW was inserted into the cortical bone of rabbit tibiae. After 12 weeks of implantation, histological evaluation was performed. There are no distinct differences on the overall cortical bone response to TWs with three different porosities. Some TWs are embedded in the cortical part of tibiae of rabbits. Almost complete bone ingrowth was observed in the space of all TWs. For TW with 60% porosity, bone formation in the part of TW which is located in medullary cavity was recognized. It is concluded that TW is expected to be useful as a non-resorbable three-dimensional scaffold in regenerative medicine. More researches for clinical application of TW are the next series of our studies.