title: Peri- and intra-implant bone response to microporous Ti coatings with surface modification.
abstract: Bone growth on and into implants exhibiting substantial surface porosity is a promising strategy in order to improve the long-term stable fixation of bone implants. However, the reliability in clinical applications remains a point of discussion. Most attention has been dedicated to the role of macroporosity, leading to the general consensus of a minimal pore size of 50-100 μm in order to allow bone ingrowth. In this in vivo study, we assessed the feasibility of early bone ingrowth into a predominantly microporous Ti coating with an average thickness of 150 μm and the hypothesis of improving the bone response through surface modification of the porous coating. Implants were placed in the cortical bone of rabbit tibiae for periods of 2 and 4 weeks and evaluated histologically and histomorphometrically using light microscopy and scanning electron microscopy. Bone with osteocytes encased in the mineralized matrix was found throughout the porous Ti coating up to the coating/substrate interface, highlighting that osseointegration of microporosities (<10 μm) was achievable. The bone trabeculae interweaved with the pore struts, establishing a large contact area which might enable an improved load transfer and stronger implant/bone interface. Furthermore, there was a clear interconnection with the surrounding cortical bone, suggesting that mechanical interlocking of the coating in the host bone in the long term is possible. When surface modifications inside the porous structure further reduced the interconnective pore size to the submicrometer level, bone ingrowth was impaired. On the other hand, application of a sol-gel-derived bioactive glass-ceramic coating without altering the pore characteristics was found to significantly improve bone regeneration around the coating, while still supporting bone ingrowth.
authors.affiliation: Department of Metallurgy and Materials Engineering (MTM), KU Leuven, Kasteelpark Arenberg 44 - bus 2450, B-3001 Heverlee, Belgium. Electronic address: Annabel.Braem@mtm.kuleuven.be.
authors.forename: Annabel
authors.initials: A
authors.lastname: Braem
authors.affiliation: Department of Oral Health Sciences, BIOMAT Research Group, KU Leuven, Kapucijnenvoer 7 blok a - bus 7001, B-3000 Leuven, Belgium.
authors.forename: Amol
authors.initials: A
authors.lastname: Chaudhari
authors.affiliation: Department of Oral Health Sciences, BIOMAT Research Group, KU Leuven, Kapucijnenvoer 7 blok a - bus 7001, B-3000 Leuven, Belgium.
authors.forename: Marcio
authors.initials: M
authors.lastname: Vivan Cardoso
authors.affiliation: Department of Metallurgy and Materials Engineering (MTM), KU Leuven, Kasteelpark Arenberg 44 - bus 2450, B-3001 Heverlee, Belgium.
authors.forename: Jan
authors.initials: J
authors.lastname: Schrooten
authors.affiliation: Department of Oral Health Sciences, BIOMAT Research Group, KU Leuven, Kapucijnenvoer 7 blok a - bus 7001, B-3000 Leuven, Belgium.
authors.forename: Joke
authors.initials: J
authors.lastname: Duyck
authors.affiliation: Department of Metallurgy and Materials Engineering (MTM), KU Leuven, Kasteelpark Arenberg 44 - bus 2450, B-3001 Heverlee, Belgium.
authors.forename: Jozef
authors.initials: J
authors.lastname: Vleugels
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000187:drug effects*; D020099:Coated Materials, Biocompatible / Q000494:pharmacology*; D008855:Microscopy, Electron, Scanning; D019736:Prostheses and Implants; D011817:Rabbits; D013499:Surface Properties; D014025:Titanium / Q000494:pharmacology*
chemical_list: D020099:Coated Materials, Biocompatible; D014025:Titanium
keywords: Bioactive glass; Bone ingrowth; Microporosity; Porous Ti coatings; Surface functionalization