Osteoinduction of porous Ti implants with a channel structure fabricated by selective laser melting

• Published in: Acta biomaterialia Vol. 7; no. 5; pp. 2327 - 2336
• Main Authors: Fukuda, A., Takemoto, M., Saito, T., Fujibayashi, S., Neo, M., Pattanayak, Deepak K., Matsushita, T., Sasaki, K., Nishida, N., Kokubo, T., Nakamura, T.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.05.2011
• Subjects: Animals; Apatites - pharmacology; Bioactive titanium; biochemical compounds; biocompatible materials; blood circulation; Bone and Bones - drug effects; Bone and Bones - pathology; bone formation; Channel structure; Computer-Aided Design; Dogs; heat treatment; Implants, Experimental; Interconnective pore size; Lasers; Materials Testing - methods; melting; Microscopy, Electron, Scanning; Organ Size - drug effects; Osseointegration - drug effects; Osteogenesis - drug effects; Osteoinduction; Porosity - drug effects; Prosthesis Implantation; Selective laser melting; Surface Properties - drug effects; Titanium - pharmacology; Selective laser melting; Osteoinduction; Channel structure; Interconnective pore size; Bioactive titanium
• ISSN: 1742-7061; 1878-7568
• DOI: 10.1016/j.actbio.2011.01.037

Many studies have shown that certain biomaterials with specific porous structures can induce bone formation in non-osseous sites without the need for osteoinductive biomolecules, however, the mechanisms responsible for this phenomenon (intrinsic osteoinduction of biomaterials) remain unclear. In particular, to our knowledge the type of pore structure suitable for osteoinduction has not been reported in detail. In the present study we investigated the effects of interconnective pore size on osteoinductivity and the bone formation processes during osteoinduction. Selective laser melting was employed to fabricate porous Ti implants (diameter 3.3 mm, length 15 mm) with a channel structure comprising four longitudinal square channels, representing pores, of different diagonal widths, 500, 600, 900, and 1200 μm (termed p500, p600, p900, and p1200, respectively). These were then subjected to chemical and heat treatments to induce bioactivity. Significant osteoinduction was observed in p500 and p600, with the highest observed osteoinduction occurring at 5 mm from the end of the implants. A distance of 5 mm probably provides a favorable balance between blood circulation and fluid movement. Thus, the simple architecture of the implants allowed effective investigation of the influence of the interconnective pore size on osteoinduction, as well as the relationship between bone quantity and its location for different pore sizes.