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@INPROCEEDINGS{Galli:205636,
      author       = {Galli, Silvia and Szakacs, Gabor and Lukac, Frantisek and
                      Vlcek, Marian and Jimbo, Ryo and Naito, Yoshihito and
                      Wennerberg, Ann and Herzen, Julia and Hammel, Joerg and
                      Willumeit, Regine},
      title        = {{O}sseointegration of resorbable magnesium screws – {A}
                      {SR}μ{CT} {S}tudy},
      journal      = {European cells $\&$ materials},
      volume       = {28},
      number       = {3},
      issn         = {1473-2262},
      address      = {Davos, Switzerland},
      publisher    = {AO fundation},
      reportid     = {PUBDB-2015-00196},
      pages        = {64},
      year         = {2014},
      note         = {OA},
      abstract     = {The development of resorbable osteofixation materials that
                      degrade upon substitution by regenerated tissue is highly
                      desirable in orthopaedics. Magnesium is promising as
                      implantable material, because of its biocompatibility,
                      osteoconductivity and biodegradation under physiological
                      conditions [1]. Through the selection of alloying elements,
                      the mechanical properties and corrosion behaviour of
                      magnesium can be modulated for application in load-bearing
                      situations. The aim of our research was to investigate the
                      bone integration and the corrosion process of Al-free
                      Mg-alloys in vivo. Our hypothesis was that Mg-based implants
                      stimulate bone growth.METHODS: Mini-screws of two different
                      Mg- alloys, Mg10Gd and Mg-Y-RE (WE43) were manufactured at
                      HZG. The cytocompatibility of the selected alloys was
                      formerly tested and validated in vitro [2, 3]. The
                      mini-screws were implanted in rats after ethical approval.
                      After 1 and 3 months of healing, cylindrical bone-implant
                      blocks were retrieved. Samples were imaged at the P05
                      Imaging Beamline (IBL) operated by HZG at PETRA III – DESY
                      (Hamburg). We used monochromatic X-rays at 25 keV to take
                      900 projections and a field of view of 7mm x 1.8 mm, which
                      resulted in 5X magnification with a resolution of ~2.5 μm.
                      3D data sets were computed using filtered back projection
                      algorithms.RESULTS: The inserted implants healed without any
                      observable adverse effect. On the basis of tomographic data,
                      we were able to compute three- dimensional renderings of
                      dvrscrews and bone with high contrast-to-noise ratios. A
                      qualitative evaluation of the data revealed inhomogeneous
                      surface corrosion of the screws, which maintained their
                      original shape within the study period. New bone formation
                      was observed in all of our samples. We found a considerable
                      increase of implant-bone contact sites with progressing
                      healing time. A quantitative analysis of the tomographic
                      data indicated spatial differences in bone density. In
                      proximity of the implant, newly formed bone matured and
                      became dense after 3 months.Top: Horizontal (left) and
                      vertical (right) sections of a screw after 3 months of
                      healing. Fragments of implants, completely integrated in the
                      bone, are visible. Bar 0.25 mm. Bottom: Orthogonal cut
                      planes (left) and volume rendering (right), showing an
                      implant (gray) into the bone (purple).DISCUSSION $\&$
                      CONCLUSIONS: The SRμCT showed osseointegration of Mg10Gd
                      and WE43. Although the spatial resolution was not sufficient
                      to fully elucidate the alloys microstructure, we observed
                      the distribution of the high absorbing regions in the
                      materials, possibly intermetallic phases and Y or RE oxides.
                      The corrosion of the alloys was slow. Biocompatibility of
                      the tested materials was confirmed by bone growth in
                      intimate contact with the implants.REFERENCES: 1 Witte F,2
                      et al (2005) Biomaterials 26:3557-3563. Feyerabend F,
                      Fischer J, et al (2010) Acta Biomater. 6:1834-1842. 3Johnson
                      I, et al. H (2011) JBMR-A.ACKNOWLEDGEMENTS: Founding from
                      the People Programme (Marie Curie Actions) Seventh Framework
                      Programme FP7/2007-2013/ under REA grant agreements n°
                      289163 and n° 312284.},
      month         = {Aug},
      date          = {2014-08-24},
      organization  = {6th Symposium on Biodegradable Metals,
                       Maratea (Italy), 24 Aug 2014 - 29 Aug
                       2014},
      cin          = {HZG},
      ddc          = {610},
      cid          = {I:(DE-H253)HZG-20120731},
      pnm          = {PETRA Beamline P05 (POF2-54G14) / FS-Proposal: I-20130475
                      EC (I-20130475-EC) / MAGNIM - Tailored biodegradable
                      magnesium implant materials (289163)},
      pid          = {G:(DE-H253)POF2-P05-20130405 / G:(DE-H253)I-20130475-EC /
                      G:(EU-Grant)289163},
      experiment   = {EXP:(DE-H253)P-P05-20150101},
      typ          = {PUB:(DE-HGF)16 / PUB:(DE-HGF)8},
      doi          = {10.3204/PUBDB-2015-00196},
      url          = {https://bib-pubdb1.desy.de/record/205636},
}