996 resultados para Substituto ósseo de fosfato de cálcio
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O processo de remodelação óssea é regulado por fatores sistêmicos e locais. Estrógeno é o hormônio mais importante na manutenção do turnover ósseo normal, cuja deficiência leva a alterações na remodelação óssea com reabsorção excedendo a formação, como observado em mulheres pós-menopausadas. O tratamento da osteoporose está relacionado com a descoberta de fármacos alternativo à terapia hormonal estrogênica compensando as desvantagens dessa terapêutica. O Raloxifeno (RLX) mimetiza os efeitos benéficos do estrógeno sem estimular tecidos como mama e endométrio. O Fluoreto de sódio (NaF) apresenta-se como agente eficaz no combate às fraturas, conseqüentes da osteoporose.
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Bone reconstructions are traditionally conducted with autogenous grafts harvested from intra- or extra-oral donor sites to reestablish the lost bone volume for further implant-prosthetic rehabilitation. The calvarial bone has been studied as an excellent donor site in large atrophic situations, presenting low resorption rates, as well as complications and minimal morbidity. The hospitalization time is short, with low pain levels, short functional limitations, and invisible scars. The skull microarchitecture is predominantly cortical in the presence of growth factors that demonstrate their osteogenic, osteoinductive, and osteoconductive abilities resulting in low resorption rate and high predictability when compared to the iliac crest. Dural lacerations, extra and subdural bleeding, cerebrospinal fluid leakage, and brain damage have been minimized due to the development of surgical technique. The delimitation of diploe, preserving the internal skull cortex before osteotomy at the donor made it possible to reduce accidents and complications. The aim of this paper is to show a technical and to discuss aspects of the use of calvarial bone in the reconstruction of severely atrophic maxilla for oral rehabilitation with osseointegrated implants.
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Bone is a specialized connective tissue, vascular and dynamic changes over the life of the organism. When injured, has a unique ability to regenerate and repair without the presence of scars, but in some situations due to the size of the defect, the bone tissue does not regenerate so completely, it is necessary to carry out bone grafting procedures. Considering there are various types of grafts and various donor sites. Thus, the aim of this study was to review the literature to some type of graft most commonly used in dentistry. Given the importance of bone reconstruction in oral and maxillofacial surgery, it is necessary to know the viability and influence of biomaterials, or not associated with autogenous grafts in bone repair. Even this, with many qualities, but further studies should be done to achieve each day, a synthetic material compatible with bone tissue lost in adequate amounts without requiring extra-oral surgeries that are considered to be devoted to higher morbidity.
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The techniques of bone reconstruction for atrophic maxillae have been improved in order to promote bone tissue growth in both height and thickness. The grafts performed with use of autogenous bone is considered the gold standard by most researchers, for demonstrating osteogenic capacity and not to promote antigenic response. However, this type of grafting is not possible to get bone tissue in large quantity for extensive renovations. In recent years, alternatives have been researched to overcome the limitations of autogenous bone. Several alternatives have been investigated to supply the disadvantages of autogenous bone grafts. In such studies, allogeneic bone grafts which are obtained from individuals with different genetic load, but from the same species have been extensively used. They can be indicated in cases of arthrosplasty, surgical knee reconstruction, and large bone defects as well as in oral and maxillofacial reconstruction. Besides showing great applicability and biocompatibility, this type of bone is available in unlimited quantities. To rehabilitate atrophic maxillae an option that has been performed with high success rate is the reconstruction with bone graft followed by osseointegrated dental implants to rehabilitate the patient aesthetics and functionally. This paper aims to show the feasibility of allogenic bone as material for reconstruction of atrophic maxilla, and subsequent rehabilitation with metal ceramic fixed prosthesis implant and dental restoration with accompanying three years through literature review and clinical case report.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Odontologia - FOA
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Introduction: In dentistry, alveolar bone resorption is a limiting factor in the well being of individuals directly interfering in the stomatognathic system, causing problems in the context of overall health. Aiming to promote biological methods that can stimulate bone regeneration, several biomimetic strategies have been developed by the use of diverse materials possible to the bone matrix, culminating in the development of techniques that promote such repair. Objective: This work is a comparative study of the performance of films made with latex as occlusive membrane for Guided Bone Regeneration (GBR) procedure in three preparations: Latex preserved in ammonia, produced by Latex rubber clones IAN873 and PR255 polymerized immediately after collection and without use ammonia as a preservative. Methods: Sixty Wistar rats were randomly divided into 4 groups of 15 animals in which bone defects of critical size (8mm diameter) were made surgically in the skull. Group A was treated by GBR through the membrane latex preserved with ammonia, Group B received the membrane made of latex from IAN873, Group C, the membrane clone PR255 and group D was not treated by GBR. After a period of 7, 15 and 50 days, 5 animals from each group were euthanized, and specimens containing bone defect collected for microscopic examination (descriptive histology and histomorphometry). Results: The results showed that after 50 days there was bone formation in higher proportions in group D (p <0.05, ANOVA followed by Tukey), suggesting that further experiments should be conducted to conclude about the presence of ammonia and the influence of kind of rubber. Conclusion: GOR is a procedure proven effective in the treatment of bone defects. Therefore, further experiments should be conducted to reach a conclusion regarding the presence of ammonia in the latex composition for the manufacture of membranes, as well as the difference induced by the species of rubber.
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This work evaluated the rainwater chemical composition and the annual atmospheric deposition in Sorocaba, (Sao Paulo State), Brazil. One sampling ˜ point was chosen and forty samples were collected between January and December 2006. The analyses were performed for pH, electrical conductivity, sodium, calcium, potassium, magnesium, sulphate, nitrate, phosphate, alkalinity and chloride. The rainwater pH varied from 5.20 to 6.40, being Ca2+ the main ion responsible for controlling the rainwater pH. The ionic concentration decreases in the following order: Ca2+>Na+> K+>Mg2+ for cations and SO2− 4 >HCO− 3 >NO− 3 >Cl−>PO3− 4 for anions. The annual atmospheric deposition appears to be controlled by the following sources: mining activities and cement factories (Ca2+ and HCO− 3 ), agricultural activities (K+, NO− 3 and PO3− 4 ), soil dust (Na+, Mg2+ and HCO− 3 ) and fossil fuel burning (SO2− 4 )
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Pós-graduação em Zootecnia - FMVZ
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One of the main challenges in the mining sector at present, related to the optimization of mineral assets, consists in to find the best proportion of each geological material to be mined and homogenized to ensure high productivity and stability in ore processing plants. The stability of a mineral processing plant is factor for achieving operational excellence, as a stable performance of the plants ensures economy and adherence to financial planning businesses. Is already well Know that the feed rate of the processing plants is dependent on the hardness and quality of the ore. Therefore, the ore behavior predictability is the solution to ensure the stability of mineral processing plants. This work was developed in Anglo American Phosphate Brazil Ltda., at the Fazenda Chapadão Phosphate Mine, located in the southeastern portion of the state of Goiás, in the municipalities of Catalão and Ouvidor. The phosphate ore is the result of supergene apatite concentration in the weathering profile of the alkaline ultramafic phlogopitized rocks, intruded by foscoritic and carbonatitic rocks series. The weathering profile has about 100 meters thick and is divided into three basic types, from top to bottom, coinciding with decreasing intensity of weathering: oxidized ore, micaceous ore and weathered rock. In each portion of this weathering profile, mainly near the contacts between these three divisions, are hard materials, cemented by minerals such as apatite, quartz, goethite, monazite and barite. The different features presented by these materials makes to be vital the correct identification, quantification and location of different hard materials in the mine area, to maximize its use. The main objective of this study was to define the type of cementation of hard materials which predominates in each portion of the weathering profile in the mine, as well as their relationship with the protolith. The work involved geological mapping, channel sampling...
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Abstract Background: Several mechanisms have been proposed to contribute to cardiac dysfunction in obesity models, such as alterations in calcium (Ca2+) handling proteins and β-adrenergic receptors. Nevertheless, the role of these factors in the development of myocardial dysfunction induced by obesity is still not clear. Objective: The purpose of this study was to investigate whether obesity induced by hypercaloric diets results in cardiac dysfunction. Furthermore, it was evaluated whether this functional abnormality in obese rats is related to abnormal Ca2+ handling and the β-adrenoceptor system. Methods: Male 30-day-old Wistar rats were fed with standard food (C) and a cycle of five hypercaloric diets (Ob) for 15 weeks. Obesity was defined as increases in body fat percentage in rats. Cardiac function was evaluated by isolated analysis of the left ventricle papillary muscle under basal conditions and after inotropic and lusitropic maneuvers. Results: Compared with the control group, the obese rats had increased body fat and glucose intolerance. The muscles of obese rats developed similar baseline data, but the myocardial responsiveness to post-rest contraction stimulus and increased extracellular Ca2+ were compromised. There were no changes in cardiac function between groups after β-adrenergic stimulation. Conclusion: Obesity promotes cardiac dysfunction related to changes in intracellular Ca2+ handling. This functional damage is probably caused by reduced cardiac sarcoplasmic reticulum Ca2+ ATPase (SERCA2) activation via Ca2+ calmodulin kinase. (Arq Bras Cardiol 2011; 97(3) : 232-240).
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)