title: Osteoconductive modifications of Ti-implants in a goat defect model: characterization of bone growth with SR muCT and histology.
abstract: In this work the osteoconductive potential of coatings for titanium implants using different extracellular matrix components was evaluated. Cylindrical implants with two defined cavities A and B were coated with collagen type I, type III, or RGD peptide, and placed in the femur of goats together with an uncoated reference state. Bone contact and volume were determined after 5 and 12 weeks implantation, using both histomorphometry and synchrotron radiation micro computed tomography (SR muCT) as the methods complement each other: SR muCT allows for a high precision of bone detection due to the large number of analysed slices per sample, while histology offers a better lateral resolution and the possibility of additionally determining bone contact. Both methods revealed similar tendencies in bone formation for the differently bio-functionalized implants, with the SR muCT data resulting in significant differences. After 5 and 12 weeks, all three coatings showed a significant increase in bone volume over the uncoated reference, with the highest results for the collagen coatings. The coating consisting of just the RGD-sequence to improve cell adhesion showed only a slight improvement compared with the reference material. For uncoated titanium, RGD, and especially collagen type I, the response in cavity A, situated in denser bone, was stronger than in cavity B. Collagen type III, on the other hand, appeared to be the more effective coating in areas of lesser bone density as represented by cavity B. These results indicate that matrix molecules (or combinations thereof) are capable of generating the appropriate signals for the specific microenvironment around implants and can thus accelerate the bone formation process and increase the stability of implants.
authors.affiliation: Max-Bergmann-Center of Biomaterials, Dresden, University of Technology, Budapester Str. 27, D-01062 Dresden, Germany. ric_bern@web.de
authors.forename: Ricardo
authors.initials: R
authors.lastname: Bernhardt
authors.forename: Juliette
authors.initials: J
authors.lastname: van den Dolder
authors.forename: Sussane
authors.initials: S
authors.lastname: Bierbaum
authors.forename: Rene
authors.initials: R
authors.lastname: Beutner
authors.forename: Dieter
authors.initials: D
authors.lastname: Scharnweber
authors.forename: John
authors.initials: J
authors.lastname: Jansen
authors.forename: Felix
authors.initials: F
authors.lastname: Beckmann
authors.forename: Hartmut
authors.initials: H
authors.lastname: Worch
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000494:pharmacology*; D001846:Bone Development; D001861:Bone Regeneration; D018786:Bone Substitutes; D001842:Bone and Bones / Q000378:metabolism; D002417:Cattle; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D024042:Collagen Type I / Q000737:chemistry; D024061:Collagen Type III / Q000737:chemistry; D005260:Female; D005269:Femur; D006041:Goats; D008855:Microscopy, Electron, Scanning; D009842:Oligopeptides / Q000737:chemistry; D016348:Osseointegration; D019736:Prostheses and Implants; D013499:Surface Properties; D017356:Synchrotrons; D013997:Time Factors; D014025:Titanium / Q000737:chemistry / Q000494:pharmacology*; D014057:Tomography, X-Ray Computed
chemical_list: D001672:Biocompatible Materials; D018786:Bone Substitutes; D020099:Coated Materials, Biocompatible; D024042:Collagen Type I; D024061:Collagen Type III; D009842:Oligopeptides; C047981:arginyl-glycyl-aspartic acid; D014025:Titanium