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Magnesium(Mg)-alloys are promising candidates as temporary implants for orthopedic and cranio-facial applications.
They can sustain tissues during healing, thanks to favorable mechanical properties, and then they slowly degrade into
biocompatible products, avoiding the need of a second surgery for implant removal. They have the potential to benefit a
vast number of patients, especially children and elderly patients. However, to be able to tailor their degradation to match
the speed of tissue regeneration it is crucial to understand how they actually degrade in the living organism. We utilized
high-resolution synchrotron-based tomography at the beamline P05 operated by HZG at the storage ring PETRA III at
DESY to study the degradation of 3 novel Mg-alloys in rat bone and the consequent bone response. On threedimensional
reconstructions of the bone-implant explants we were able to follow the dynamic transformation that the
materials underwent at different healing times and on the basis of absorption coefficients we could distinguish and
quantify the amount of remaining implants, the corrosion layers and the new bone. This was a great advantage compared
to laboratory CT, for which the limitation in contrast and in resolution made impossible to discriminate between original
alloy, degradation products and bone, leading to inaccurate determination of the materials degradation rates. The same
samples imaged by tomography were used for non-decalcified histology. The combination of histological and
tomographical images provided new insight on the nature of the bone-to-implant interface and of the degradation
products, which appeared to have great similarities to the host bone.
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