Navegando por Palavras-chave "calcium phosphate cements"

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    Scaffolds of calcium phosphate cement containing chitosan and gelatin
    (ABM, ABC, ABPol, 2013-12-01) Renó, C. O. [UNIFESP]; Lima, B.f.a.s. [UNIFESP]; Trichês, Eliandra de Sousa [UNIFESP]; Bertran, C.a.; Motisuke, Mariana [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Universidade Estadual de Campinas (UNICAMP)
    Calcium phosphate cements (CPCs) have potential to be used on repairing damaged bones due to their moldability, bioactivity and bioresorbability. These materials combine calcium orthophosphate powders with a liquid leading to a paste that hardens spontaneously at low temperatures. Hence, CPCs could be applied as scaffolds to support cell/tissue growth. This paper studies CPC scaffolds processing by foaming cement's liquid phase in which was added gelatin and chitosan. The former acted to increase the foam stability while the ladder acted as a foaming agent. Moreover, these polymers would enhance scaffold's biological properties by controlling material's total porosity and in vivo resorption. The method proposed led to scaffolds with 58.71% porosity with sizes ranging from 160 to 760 µm and compressive strength of 0.70MPa. After foaming, pores' size, distribution and interconnectivity changed significantly leading to a material that could be applied on bone regeneration since it would allow nutrient's transport, cell attachment and an increase in material degradation rate.
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    Si-TCP synthesized from Mg-free reagents employed as calcium phosphate cement
    (ABM, ABC, ABPol, 2012-08-01) Motisuke, Mariana [UNIFESP]; Carrodeguas, Raul García; Zavaglia, Cecília Amélia de Carvalho; Universidade Federal de São Paulo (UNIFESP); Universidade Estadual de Campinas (UNICAMP)
    The influence of silicon doping on calcium phosphate cement were explored in this work. α-TCP and Si-α-TCP were prepared by solid state reaction employing Mg-free CaHPO4, CaCO3 and CaSiO3 as precursors. It was possible to obtain TCP powders with low contents of β phase as contaminant. Cement liquid phase was an aqueous solution containing 2.5 wt. (%) of Na2HPO4 and 1.5 wt. (%) of citric acid. The liquid-to-powder ratio was 0.6 mL.g-1. Chemical, physical and mechanical properties of the cement samples were determined by means of XRD, FTIR, XRF, compressive strength and SEM. The calcium phosphate cements obtained achieved satisfactory properties; however, Si-α-TCP presented a decrease on the rate of setting reaction.
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    Si-tricalcium phosphate cement: preparation, characterization and bioactivity in SBF
    (ABM, ABC, ABPol, 2011-12-01) Motisuke, Mariana [UNIFESP]; Carrodeguas, Raúl García; Zavaglia, Cecília Amélia De Carvalho; Universidade Federal de São Paulo (UNIFESP); Universidade Estadual de Campinas (UNICAMP); Consejo Superior de Investigaciones Científicas Instituto de Cerámica y Vidrio
    There are evidences considering the effectiveness of Si on enhancing biological properties of calcium phosphates; however, there are not many works relating to the Si-alpha-TCP bone cement. The influence of silicon doping on the properties of Α-TCP cement was analyzed. Si-TCP was obtained by a solid state reaction employing CaCO3, CaHPO4 and CaSiO3 and powder was analyzed by XRD, FTIR, XRF and BET specific area. Cement samples were analyzed for their surface of fracture morphology, mechanical resistance and SBF bioactivity. Cement mechanical resistance was not satisfactory for biomedical application; nonetheless, sample's surface was coated by an apatite layer after immersion in SBF. Notwithstanding, to ensure that silicon is the element responsible for increasing the material's bioactivity it is necessary to evaluate the in vivo performance of the bone cement obtained in this work.