Navegando por Palavras-chave "hydroxyapatite"

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    Effects of cigarette smoke inhalation and coffee consumption on bone formation and osseous integration of hydroxyapatite implant
    (Instituto Internacional de Ecologia, 2013-02-01) Andrade, Ana R.; Sant'ana, Dcm.; Mendes Junior, Ja.; Moreira, Maria Eliza Castro; Pires, Gc.; Santos, Mp.; Fernandes, Geraldo Jose Medeiros [UNIFESP]; Nakagaki, Wilson Romero; Garcia, Jad.; Lima, Cc.; Soares, Ea.; Universidade José do Rosário Vellano; Universidade Federal de São Paulo (UNIFESP); Universidade Federal de Alfenas; Universidade Estadual de Campinas (UNICAMP); Universidade José do Rosário Vellano Faculdade de Medicina
    The present study aims to assess the effects of cigarette smoke inhalation and/or coffee consumption on bone formation and osseous integration of a dense hydroxyapatite (DHA) implant in rats. For this study, 20 male rats were divided into four groups (n = 5): CT (control) group, CE (coffee) group, CI (cigarette) group and CC (coffee + cigarette) group. During 16 weeks, animals in the CI group were exposed to cigarette smoke inhalation equivalent to 6 cigarettes per day; specimens in the CE group drank coffee as liquid diet; and rats in the CC group were submitted to both substances. In the 6th week a 5 mm slit in the parietal bone and a 4 mm slit in the tibia were performed on the left side: the former was left open while the latter received a DHA implant. As soon as surgeries were finished, the animals returned to their original protocols and after 10 weeks of exposure they were euthanised (ethically sacrificed) and the mentioned bones collected for histological processing. Data showed that exposure to cigarette smoke inhalation and coffee consumption did not interfere in weight gain and that solid and liquid diet consumption was satisfactory. Rats in the CC group showed a decrease in bone neoformation around the tibial DHA implant (31.8 ± 2.8) as well as in bone formation in the parietal slit (28.6 ± 2.2). On their own, cigarette smoke inhalation or coffee consumption also led to diminished bone neoformation around the implant and delayed the bone repair process in relation to the CT group. However, reduction in the bone repair process was accentuated with exposure to both cigarette smoke inhalation and coffee consumption in this study.
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    Preparation and characterization of stainless steel 316L/HA biocomposite
    (ABM, ABC, ABPol, 2013-04-01) Silva, Gilbert; Baldissera, Márcia Regina; Trichês, Eliandra de Sousa [UNIFESP]; Cardoso, Kátia Regina [UNIFESP]; Universidade Federal de Itajubá IEM; Universidade Federal de Itajubá Instituto de Ciências Exatas; Universidade Federal de São Paulo (UNIFESP)
    The austenitic stainless steel 316L is the most used metallic biomaterials in orthopedics applications, especially in the manufacture of articulated prostheses and as structural elements in fracture fixation, since it has high mechanical strength. However, because it is biologically inactive, it does not form chemical bond with bone tissue, it is fixed only by morphology. The development of biocomposites of stainless steel with a bioactive material, such as hydroxyapatite - HA, is presented as an alternative to improve the response in the tissue-implant interface. However significant reductions in mechanical properties of the biocomposite can occur. Different compositions of the biocomposite stainless steel 316L/HA (5, 20 and 50 wt. (%) HA) were prepared by mechanical alloying. After milling the powders for 10 hours, the different compositions of the biocomposite were compacted isostatically and sintered at 1200 ºC for 2 hours. The mechanical properties of the biocomposites were analyzed by compression tests. The powders and the sintered composites were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD).