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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    European journal of orthopaedic surgery & traumatology 7 (1997), S. 79-84 
    ISSN: 1432-1068
    Schlagwort(e): Biomaterial ; Calciumphosphate ceramics ; Osteoconduction ; Resorption ; Mechanical strength ; Biomatériau ; Céramiques de phosphate de calcium ; Résorption
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé Les céramiques macroporeuses biphasées de phosphate de calcium sont biocompatibles. Leurs structures physico-chimiques sont proches de la phase minérale des tissus osseux et dentaires et assurent leur bioactivité. Très rapidement, aprè implantation en site osseux, une dissolution apparaît avec précipitation d'ions calcium et phosphore et formation de cristaux d'apatites biologiques. A court terme une résorption ostéoclastique débute l'ostéoconduction à l'intérieur des macropores. Les études mécaniques révèlent une amélioration significative des propriétés mécaniques du fait du développement de l'os trabéculaire. En site vertébral, les expérimentations animales ont démontré la cinétique de la réhabitation osseuse au sein du matériau, ce qui permet une arthrodèse postéro-latérale. La rigidité de la fusion intervertébrale est équivalente à celle obtenue avec de l'os autologue. Ainsi, pour des conditions précises d'utilisation, les céramiques poreuses de phosphate de calcium peuvent être utilisées pour combler le défect osseux et pour la réalisation d'arthrodéses postéro-latérales.
    Notizen: Summary Macroporous biphasic calcium phosphate ceramics are biocompatible. Their physico-chemical structure is close to the mineral phase of the bone and provides bioactivity. Shortly after implantation in osseous area, dissolution appears with precipitation and formation of apatite crystals. Soon after osteoclastic resorption begins osteoconduction inside the macropores. Mechanical studies reveal a significant improvement in the mechanical properties due to the growth of the trabecular bone. Animal experiments in the spine have demonstrated bone penetration which allows a postero-lateral fusion. The rigidity of the fusion is equivalent to that obtained with bone graft. Macroporous biphasic calcium phosphate can be applied to fill bone defects and for postero-lateral spine fusion.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Journal of materials science 8 (1997), S. 67-73 
    ISSN: 1573-4838
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin , Technik allgemein
    Notizen: Abstract The evaluation of composite anterior cruciate ligament prostheses, theunion of an inductor of collagen and a synthetic fibre, are described. They wereimplanted in 10 sheep models for six months. None of the ligaments were broken,and the dynamic radiography was stable during this time. After harvesting them,a histologic study was performed on the intra-osseou and intra-articularportion, and on the synovial tissue. Biocompatibility was excellent. An osseousanchorage was found in 50% of cases and a fibrous ingrowth with well orientedfibres in each case. The results of this study show that the matrix has onlypartially played its role, because there was no improvement of fibrous ingrowthcompared with other studies. However this fact corresponds to results at only 6months and it is necessary to identify the type of collagen.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    ISSN: 1573-4838
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin , Technik allgemein
    Notizen: The aim of this study was to determine if the compressive strength of a macroporous biphasic calcium phosphate ceramic (MBCP) changed with post-implantation physicochemical transformations, in the absence of true bone deposition. MBCP cylinders were implanted in rabbit femurs and muscles. Compressive strength measurements and Fourier transform infrared (FTIR) spectroscopy measurements were performed after 1,2,3,6 and 12 weeks. MBCP blocks implanted in a human and removed after 1 week due to a clinical problem were also submitted to the same analyses. Results showed that compressive strength increased in both osseous and muscular sites. Mechanical improvement was also measured on MBCP implanted in a human. Physico-chemical changes, particularly biological apatite precipitations, were evident in MBCP implanted in muscle and in a human. This study has shown that the compressive strength of MBCP increased after implantation, even in the absence of true bone deposition. This suggests that in vivo physico-chemical processes could improve the mechanical properties of MBCP.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    ISSN: 1573-4838
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin , Technik allgemein
    Notizen: The results of microscopic and spectroscopic analysis of a mixture of biphasic calcium phosphate (BCP) powder and cellulose ether aqueous sol are reported in this study. This new composite is injectable and is aimed to be used as bone substitute for spine surgery. The influence of the polymer on the physico-chemical properties of BCP was investigated by complementary techniques such as scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), infrared and Raman spectroscopies and X-ray photoelectron spectroscopy (XPS). When brought into contact with the polymer solution, the ceramic is modified in its granulometry, crystallinity, and surface chemistry. A dissolution/precipitation reaction occurs, leading to a phosphorus-rich and amorphous outer layer of the ceramic surface. Moreover, the bonding state of the composite involves new features that could be assigned to calcium complexes (calcium carbonate or calcium hydroxide).
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 42 (1998), S. 368-375 
    ISSN: 0021-9304
    Schlagwort(e): particulate biphasic calcium phosphate ; long-term bone implantation ; inflammatory reaction ; histomorphometry ; material degradation ; Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Biphasic calcium phosphate particles (BCP), alone or combined with a cellulosic ether vehicle in an injectable composite material (COMP), were implanted in femurs of rabbits. The long-term follow-up (up to 78 weeks) indicated: (1) BCP and COMP induced a foreign-body inflammatory reaction but without fibrous encapsulation. Phagocytosis was mediated by mononucleated macrophages (MC) and giant multinucleated cells (GMNC). Phagocytosis was stronger with COMP and required the recruitment of GMNC while it primarily involved MC in the case of BCP. (2) There appeared to be no significant difference between the bone ingrowth in the defects packed with BCP (dBCP) and in those filled with COMP (dCOMP). Bone reconstruction mostly was achieved after 4 weeks in dBCP but took more time to reach the center of dCOMP. High bone remodeling was observed at the last evaluation times, especially in the case of COMP. (3) Degradation of the materials occurred mainly during the first 4 weeks and was more severe for COMP, which probably was related to the smaller granulometry of its mineral phase. Cell-mediated degradation went on for the 78 weeks and followed two processes: phagocytosis and/or extracellular dissolution of the calcium phosphate particles. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 42, 368-375, 1998.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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