FRANCISCO JOSE CORREA BRAGA
44 resultados
Resultados de Busca
Agora exibindo 1 - 10 de 44
Artigo IPEN-doc 24741 Amorphous calcium phosphate (ACP) in tissue repair process2018 - ALLEGRINI JUNIOR, SERGIO; SILVA, ANTONIO C. da; TSUJITA, MARISTELA; SALLES, MARCOS B.; GEHRKE, SERGIO A.; BRAGA, FRANCISCO J.C.Synthetic biomaterials submitted to new structural technologies have become ideal for the recovery of traumatized bone tissues and some bone substitutes such as bioactive glass, β‐Tricalcium phosphate (β‐TCP) and amorphous calcium phosphate (ACP) are being used in areas of tissue defects. For this study, ACP was produced in the form of fibers and then submitted to cytotoxicity testing. A sample of ACP was inserted into the mandibular region of a patient with a lost implant so after removal and curettage, the remaining bone site was filled with the ACP biomaterial. Preliminary cytotoxicity test was negative. After 15 weeks of healing, a titanium implant was inserted at the site. Clinical and radiographic follow‐up was conducted for 12 months and sequential radiographic analyses revealed tissue formation resembling spongy bone. Images under immunohistochemistry demonstrated efficient deposition and osteoconduction of the newly deposited tissue. Residual portion of the CaO:P2O5 outer layers served as a substrate for osteoid matrix deposition, aiding growth, and the results of fiber absorption favored maturation of the new bone tissue.Artigo IPEN-doc 23073 Osteoconductive properties of two different bioactive glass forms (powder and fiber) combined with collagen2017 - MAGRI, ANGELA M.P.; FERNANDES, KELLY R.; UENO, FABIO R.; KIDO, HUELITON W.; SILVA, ANTONIO C. da; BRAGA, FRANCISCO J.C.; GRANITO, RENATA N.; GABBAI-ARMELIN, PAULO R.; RENNO, ANA C.M.Bioactive Glasses (BG) is a group of synthetic silica-based materials with the unique ability to bond to living bone and can be used in bone repair. Although the osteogenic potential of BG, this material may have not present sufficient osteoconductive and osteoinductive properties to allow bone regeneration, especially in compromised situations. In order to overcome this limitation, it was proposed the combination the BG in two forms (powder and fiber) combined with collagen type I (COL-1). The aim of this study was to evaluate the BG/COL-based materials in terms of morphological characteristics, physicochemical features and mineralization. Additionally, the second objective was to investigate and compare the osteoconductive properties of two different bioactive glass forms (powder and fiber) enriched or not with collagen using a tibial bone defect model in rats. For this, four different formulations (BG powder – BGp, BG powder enriched with collagen – BGp/Col, BG fibers – BGf and BGp fibers enriched with collagen – BGf/Col) were developed. The physicochemical and morphological modifications were analyzed by SEM, FTIR, calcium assay and pH measurement. For in vivo evaluations, histopathology, morphometrical and immunohistochemistry were performed in a tibial defect in rats. The FTIR analysis indicated that BGp and BGf maintained the characteristic peaks for this class of material. Furthermore, the calcium assay showed an increased Ca uptake in the BG fibers. The pH measurements revealed that BGp (with or without collagen) presented higher pH values compared to BGf. In addition, the histological analysis demonstrated no inflammation for all groups at the site of the injury, besides a faster material degradation and higher bone ingrowth for groups with collagen. The immunohistochemistry analysis demonstrated Runx-2 and Rank-L expression for all the groups. Those findings support that BGp with collagen can be a promising alternative for treating fracture of difficult consolidation.Artigo IPEN-doc 23919 Direct manufacture of hydroxyapatite scaffolds using blue laser2015 - MEIRA, CAMILA R. de; GOMES, DANNYLO T.; BRAGA, FRANCISCO J.C.; PURQUERIO, BENEDITO de M.; FORTULAN, CARLOS A.The study deals with the direct manufacturing of hydroxyapatite scaffolds using selective polymerization of the slurry liquid phase. The bovine hydroxyapatite has great similarity with the human bone structure, making it able for a direct connection with the bone tissues. This study aims to obtain scaffolds using a new technique of rapid prototyping, obtained by polymerization of acrylic resin (liquid phase of slurry) by ultraviolet light present in a range of the band spectrum emitted by the blue laser light. Sub-micrometer hydroxyapatite was obtained by the calcination and grinding of bovine bone in a vibratory mill. Mixtures of hydroxyapatite and resin were prototyped in three-dimensional pieces and sintered afterword and subjected to blue laser emission path directed in a CNC equipment. Grounded particles obtained in the grinding vibratory mill, with equivalent diameter of 0.35 microns, were reactive enough to compensate the low green densification bellow 50 vol%. Polymerization tests realized indicated that the incidence of the laser with fluency of 170 mW.s/mm2 promoted the curing of the 0.5 mm diameter pieces in depth about 0.5 mm, which allowed the prototyping of the scaffolds with sufficient mechanical strength for handling.Artigo IPEN-doc 23530 Calcium phosphate fibers coated with collagen: In vivo evaluation of the effects on bone repair2016 - UENO, FABIO R.; KIDO, HUELITON W.; GRANITO, RENATA N.; GABBAI-ARMELIN, PAULO R.; MAGRI, ANGELA M.P.; FERNANDES, KELLY R.; SILVA, ANTONIO C. da; BRAGA, FRANCISCO J.C.; RENNO, ANA C.M.The aim of this study was to assess the characteristics of the CaP/Col composites, in powder and fiber form, via scanning electron microscopy (SEM), pH and calcium release evaluation after immersion in SBF and to evaluate the performance of these materials on the bone repair process in a tibial bone defect model. For this, four different formulations (CaP powder – CaPp, CaP powder with collagen – CaPp/Col, CaP fibers – CaPf and CaP fibers with collagen – CaPf/Col) were developed. SEM images indicated that both material forms were successfully coated with collagen and that CaPp and CaPf presented HCA precursor crystals on their surface. Although presenting different forms, FTIR analysis indicated that CaPp and CaPf maintained the characteristic peaks for this class of material. Additionally, the calcium assay study demonstrated a higher Ca uptake for CaPp compared to CaPf for up to 5 days. Furthermore, pH measurements revealed that the collagen coating prevented the acidification of the medium, leading to higher pH values for CaPp/Col and CaPf/Col. The histological analysis showed that CaPf/Col demonstrated a higher amount of newly formed bone in the region of the defect and a reduced presence of material. In summary, the results indicated that the fibrous CaP enriched with the organic part (collagen) glassy scaffold presented good degradability and bone-forming properties and also supported Runx2 and RANKL expression. These results show that the present CaP/Col fibrous composite may be used as a bone graft for inducing bone repair.Capítulo IPEN-doc 22707 Evaluation of biomimetic coatings on femtosecond laser treated alumina and alumina-zirconia composite surfaces2016 - AGUIAR, A.A.; LIMA, N.B. de; BRAGA, F.J.C.; ROSSI, W.; COUTO, A.A.; BALDAN, R.The effect of texturing Al2O3 and Al2O3/ZrO2 surfaces using fem- 7 tosecond laser has been evaluated in terms of the roughness, wettability and 8 microstructure of the substrate to increase growth efficiency and adhesion of 9 hydroxyapatite. Femtosecond laser treatment of these materials causes phase 10 transformation from alpha-alumina to gamma-alumina. Heat effects during fem- 11 tosecond laser treatment causes the grains to be in the nanometer scale. Without 12 heat effects, the grains are in the micrometer scale. The use of femtosecond laser 13 permits control of the surface roughness of the alumina specimens. The higher the 14 femtosecond laser energy, the higher is the wettability of the specimen and the total 15 surface energy. Specimens with laser textured surfaces upon immersion in 1.5 SBF 16 for 6 and 15 days revealed apatite layers well bonded to the substrate and without 17 detachment. The adhesion of apatite to surfaces of specimens that were not textured 18 with femtosecond laser was inadequateArtigo IPEN-doc 22522 Livro IPEN-doc 17979 Materiais aplicados à medicina e odontologia2015 - BRAGA, FRANCISCO J.C.Artigo IPEN-doc 20512 Dispersed hydroxyapatite and modified bioglass 45S5 composites: sintering behavior of glass matrix ranging from 20 to 30 wt% in calcium oxide investigation2014 - SILVA, A.C.; PARRA-SILVA, J.; SANTOS, S.C.; SETZ, L.F.G.; MELLO CASTANHO, S.R.H.; BRAGA, F.J.C.Artigo IPEN-doc 20331 Fibras de fosfato de cálcio amorfo: fases amorfas coaxiais orientando a bioatividade2014 - SILVA, A.C.; MELLO CASTANHO, S.R.H.; LIMA, N.B.; BRAGA, F.J.C.Artigo IPEN-doc 20326 Vidros com efeito percolativo: possível modelo composicional2014 - SILVA, A.C.; SETZ, L.F.G.; SANTOS, S.C.; BRAGA, F.J.C.; MELLO CASTANHO, S.R.H.