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Finite element analysis and cellular studies on advanced, controlled porous structures with subsurface continuity in bio‐implantable titanium alloys
Author(s) -
Lambert P.,
Ankem S.,
Wyatt Z.,
Ferlin K. M.,
Fisher J.
Publication year - 2014
Publication title -
journal of biomedical materials research part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.849
H-Index - 150
eISSN - 1552-4965
pISSN - 1549-3296
DOI - 10.1002/jbm.a.34684
Subject(s) - materials science , titanium , implant , titanium alloy , interconnectivity , porosity , stress shielding , electrical discharge machining , bone tissue , composite material , finite element method , biomedical engineering , machining , metallurgy , alloy , structural engineering , medicine , surgery , engineering , artificial intelligence , computer science
Highly‐porous metallic implant onlay materials (specifically those containing surface pores that intersect beneath the onlay surface) have been investigated recently for their potential to reduce bone resorption and to improve the overall stability of the implant. In the current study, sub‐surface interconnectivity of high‐aspect‐ratio pores was created directly in the substrate of an implant material using wire electrical discharge machining (EDM). This technique was used to produce intersecting pores with diameters of 180–250 μm on a clinically relevant implant material—commercially pure (CP) Grade 4 Ti—with a very high degree of control over pore morphology. These pores resulted in no significant microstructural modification to the surrounding Ti, and the inner pore surfaces could be thermally oxidized to produce a microrough, bioactive TiO 2 layer. Finite element analysis of Ti models containing these EDM‐attainable intersecting pore geometries suggested they produce higher bone/implant interface strengths and lower susceptibility to stress shielding of the surrounding bone as compared with models containing simpler surface geometries. In vitro experiments using mesenchymal stem cells (MSCs) demonstrated mineralized tissue ingrowth of ∼ 300 μm into EDM‐produced pores. This amount of ingrowth is expected to allow for full interlocking of mineralized tissue and implant given the proper pore structure design. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 225–233, 2014.