Laser Sintered Porous Ti–6Al–4V Implants Stimulate Vertical Bone Growth

• Published in: Annals of biomedical engineering 2017-08, Vol.45 (8), p.2025-2035
• Main Authors: Cheng, Alice, Cohen, David J., Kahn, Adrian, Clohessy, Ryan M., Sahingur, Kaan, Newton, Joseph B., Hyzy, Sharon L., Boyan, Barbara D., Schwartz, Zvi
• Format: Article
• Language: English
• Subjects: Biochemistry; Biocompatibility; Biological and Medical Physics; Biomedical and Life Sciences; Biomedical Engineering and Bioengineering; Biomedical materials; Biomedicine; Biophysics; Bone Development - physiology; Bone growth; Bone implants; Bone matrix; Bone morphogenetic protein 2; Calvaria; Cancellous bone; Cell morphology; Cells, Cultured; Classical Mechanics; Cytology; Demineralizing; Electron imaging; Equipment Failure Analysis; Female; Heating - methods; Humans; Laser sintering; Lasers; Male; Materials Testing; Osseointegration; Osteoblasts; Osteoblasts - cytology; Osteoblasts - physiology; Osteocalcin; Osteogenesis; Osteogenesis - physiology; Osteoprotegerin; Porosity; Powders; Prosthesis Design; Stability analysis; Surface Properties; Surface roughness; Surgical implants; Titanium - chemistry; Titanium - radiation effects; Titanium base alloys; Transplants & implants; Vascular endothelial growth factor; Young Adult
• ISSN: 0090-6964; 1573-9686
• DOI: 10.1007/s10439-017-1831-7

The objective of this study was to examine the ability of 3D implants with trabecular-bone-inspired porosity and micro-/nano-rough surfaces to enhance vertical bone ingrowth. Porous Ti–6Al–4V constructs were fabricated via laser-sintering and processed to obtain micro-/nano-rough surfaces. Male and female human osteoblasts were seeded on constructs to analyze cell morphology and response. Implants were then placed on rat calvaria for 10 weeks to assess vertical bone ingrowth, mechanical stability and osseointegration. All osteoblasts showed higher levels of osteocalcin, osteoprotegerin, vascular endothelial growth factor and bone morphogenetic protein 2 on porous constructs compared to solid laser-sintered controls. Porous implants placed in vivo resulted in an average of 3.1 ± 0.6 mm 3 vertical bone growth and osseointegration within implant pores and had significantly higher pull-out strength values than solid implants. New bone formation and pull-out strength was not improved with the addition of demineralized bone matrix putty. Scanning electron images and histological results corroborated vertical bone growth. This study indicates that Ti–6Al–4V implants fabricated by additive manufacturing to have porosity based on trabecular bone and post-build processing to have micro-/nano-surface roughness can support vertical bone growth in vivo, and suggests that these implants may be used clinically to increase osseointegration in challenging patient cases.