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Avaliação clínica, histológica e histomorfométrica do reparo de defeitos ósseos criados em mandíbula de cães preenchidos com Biovidro 45S5 ou Biosilicato® após a colocação de implantes osseointegráveis; Bone formation on Ti implants in intra-bony defect sites filled with different bone substitutes: histomorphometric analysis in dogs

Jabur, Roberto de Oliveira
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 31/10/2008 Português
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56.58%
O presente trabalho avaliou a formacao de tecido osseo ao redor de implantes osseointegraveis de titanio, apos realizacao de defeitos osseos, utilizando diferentes tipos de substitutos osseos. Foram utilizados 5 caes de raca indeterminada, os pre molares e molares mandibulares foram extraidos, passados 12 semanas, os caes foram submetidos a um novo procedimento cirurgico aonde foram realizadas as perfurações preconizados pelo fabricante dos implantes, o osso vestibular da mandibula foi desgastado ate que parte da perfuracao fosse exposta, os implantes entao foram colocados nas respectivas perfuracoes, ficando com 4 espiras expostas. Esses defeitos foram preenchidos aleatoriamente com Bioglass® 45S5, Biosilicato® , Osso autogeno, e sem nenhum material de preenchimento. 18 semanas depois da colocacao dos implantes os caes foram mortos e suas hemi-mandibulas contendo os implantes removidas e submetidas aos analises histologiaos e histomorfometricas, os dados obtidos foram submetidos ao teste de Kruskal-Wallis. A histologia dos 4 grupos estudados revelaram a presenca de tecido osseo maduro em contato com os implantes, porem sem ralacao direta com os vidros bioativos e osso autogeno. A porcentagem de contato osso implante, matriz ossea mineralizada ao redor da espira...

Desenvolvimento e caracterização de um cimento ósseo esponjoso para preenchimento de falhas ósseas. Análise morfométrica e ensaio mecânico; Development and characterization of a cancellous cement repair of bone defects. Morphometric analisys and mechanical testing

Cimatti, Bruno
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 28/06/2012 Português
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46.46%
Introdução: O tratamento dos tumores ósseos benignos é frequentemente realizado por abordagem intralesional com curetagem do tumor e preenchimento da falha óssea com substâncias biológicas ou sintéticas. Entre as biológicas estão os vários tipos de enxertos e o maior representante das sintéticas é o cimento ósseo ou polimetilmetacrilato (PMMA). O uso do cimento ósseo compacto pode apresentar problemas devido à necrose térmica, ao afrouxamento asséptico, à incapacidade de remodelação e à elasticidade inadequada em relação ao osso normal. O desenvolvimento de um cimento ósseo esponjoso que atenda a estas demandas mecânicas e biológicas e que seja de fácil manipulação no ambiente cirúrgico tem estimulado alguns pesquisadores. Basicamente, é possível formar poros no interior do cimento por mistura de substâncias hidrossolúveis ou por reação química produtora de gás. Objetivo: Desenvolver e caracterizar fisicamente e mecanicamente um cimento ósseo com poros intercomunicantes de aspecto estrutural esponjoso. Material e métodos: A produção de cimento esponjoso foi realizada misturando-se o PMMA com bicarbonato de sódio e ácido cítrico. Foram confeccionados 90 corpos de prova com 40 mm de altura por 20 mm de diâmetro distribuídos em 6 grupos (n=15): G1 formado por cimento esponjoso em que antes da polimerização do cimento foram adicionados bicarbonato de sódio e ácido cítrico na proporção de 10% em relação ao componente sólido do cimento (polímero); G2 - cimento esponjoso na proporção de 20%; G3 - cimento esponjoso na proporção de 30%; G4 - cimento ósseo de PMMA compacto; G5 - formado por cimento de poliuretana de mamona (Bioósteo®) na proporção de 20%; G6 formado de corpos de prova cilíndricos de osso esponjoso extraído com trefina de côndilos tibiais proximais de bovinos. A qualidade do cimento esponjoso foi avaliada por macroscopia...

Análise da utilização do osteoscafTM como substituto ósseo em cirurgia de levantamento de seio maxilar; Use of OsteoScaf™ in maxillary sinus augmentation

Cardoso, Camila Lopes
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 04/03/2013 Português
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46.64%
Procedimentos de levantamento do seio maxilar têm sido realizados para aumentar o volume ósseo e promover a estabilidade do implante, na região posterior de maxilas severamente atrofiadas. Ao longo dos anos, resultados de vários estudos demonstraram que alguns substitutos ósseos podem suportar implantes em função, após o levantamento de seio maxilar, igual ou melhor quando utilizado o osso autógeno. Neste estudo, foi avaliado o comportamento de um substituto ósseo completamente biodegradável (OsteoScaf™) no modelo experimental de levantamento de seio maxilar em coelhos. Além disso, ele foi comparado com o osso autógeno e outros dois substitutos ósseos, não totalmente biodegradáveis, disponíveis comercialmente (Bio-Oss® e BoneCeramic®). Avaliação clínica, tomografia computadorizada por feixe cônico, microtomografia computadorizada, análises microscópicas e análise molecular, através da técnica de PCR, foram realizadas após 2, 4 e 8 semanas de cirurgia. O levantamento de seio maxilar utilizando o osso autógeno demonstrou maior reabsorção, ao longo do tempo, comparado aos substitutos ósseos, os quais revelaram maior neoformação óssea após 8, 4 e 2 semanas, respectivamente. O grupo Bio-Oss® apresentou maior neoformação óssea...

A utilização da proteína morgogenética óssea recombinante humana 2 com carreadores adicionais: análise histomorfométrica e por microtomografia computadorizada 3D; The use of the human recombinant bone morphogenetic protein 2 with additional carriers: Histomorphometric and 3D Micro-computed tomography analysis

Polo, Cristiane Ibanhes
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 12/12/2013 Português
Relevância na Pesquisa
46.26%
A utilização de osteoindutores como a proteína morfogenética óssea recombinante humana tipo 2 (rhBMP-2) em cirurgia oral e maxilofacial para reparação e regeneração óssea tem aumentado progressivamente. Porém, suas indicações ainda estão limitadas a preenchimento de cavidades e pequenas reconstruções. Este estudo teve como objetivo analisar e comparar, por meio da microtomografia computadorizada tridimensional (Micro-TC 3D) e histomorfometria, a arquitetura óssea, a taxa de osso neoformado e a taxa de biodegradação do -Tricálcio Fostato (-TCP), Fosfato de Cálcio Bifásico (BCP) e Osso Mineral Bovino (BBM), utilizados como carreadores adicionais à rhBMP-2/esponja de colágeno (ACS) em um modelo de regeneração óssea guiada (ROG) vertical em calvária de coelhos. Quatro cilindros de titânio foram fixados à calvária de 20 coelhos da raça Nova Zelândia. No Grupo 1 (n = 10), 3 cilindros foram aleatoriamente preenchidos com um dos materiais teste utilizados como carreadores e um cilindro foi preenchido com coágulo sanguíneo (CO). No Grupo 2 (n = 10), os cilindros foram aleatoriamente designados para os mesmos materiais e coágulo sanguíneo, com a adição da rhBMP-2/ACS. Após 14 semanas de reparação, as amostras foram coletadas e enviadas para a aquisição de imagens da Micro-TC e processamento histológico. De acordo com a análise histomorfométrica...

Histologic Evaluation of the Osteoinductive Property of Autogenous Demineralized Dentin Matrix on Surgical Bone Defects in Rabbit Skulls Using Human Amniotic Membrane for Guided Bone Regeneration

Gomes, Mônica Fernandes; Da Silva Dos Anjos, Mário James; De Oliveira Nogueira, Terezinha; Catanzaro Guimarães, Sérgio Augusto
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 563-571
Português
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46.27%
The aim of this investigation was to evaluate the osteoinductive property of autogenous demineralized dentin matrix (ADDM) on experimental surgical bone defects in the parietal bone of rabbits using the guided bone regeneration (GBR) technique incorporating human amniotic membrane (HAM). Thirty-six rabbits were divided into 2 groups, HAM and ADDM+HAM. It was possible to conclude that HAM did not interfere with bone repair and was resorbed. Slices of ADDM induced direct bone formation and were incorporated by the newly formed bone tissue and remodeled. The bone defects healed faster in the ADDM+HAM group than in the group with HAM only.

Bone healing in surgically created defects treated with either bioactive glass particles, a calcium sulfate barrier, or a combination of both materials: A histological and histometric study in rat tibias

Melo, Luiz G. N.; Nagata, Maria J. H.; Bosco, Alvaro F.; Ribeiro, Luciana L. G.; Leite, Cristiane M.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 683-691
Português
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46.46%
Objective: The purpose of this study was to histologically analyze the influence of bioactive glass and/or a calcium sulfate barrier on bone healing in surgically created defects in rat tibias. Material and methods: Sixty-four rats were divided into 4 groups: C (control), CS (calcium sulfate), BG (bioactive glass), and BG/CS (bioactive glass/calcium sulfate). A surgical defect was created in the tibia of each animal. In Group CS, a calcium sulfate barrier was placed to cover the defect. In Group BG the defect was filled with bioactive glass. In Group BG/CS, it was filled with bioactive glass and protected by a barrier of calcium sulfate. Animals were sacrificed at 10 or 30 days post-operative. The formation of new bone in the cortical area of the defect was evaluated histomorphometrically. Results: At 10 days post-operative, Group C presented significantly more bone formation than Groups CS, BG, or BG/CS. No statistically significant differences were found between the experimental groups. At 30 days post-operative, Group C demonstrated significantly more bone formation than the experimental groups. Groups CS and BG/CS showed significantly more bone formation than Group BG. No statistically significant differences were found between Group CS and BG/CS. Conclusions: (a) the control groups had significantly more bone formation than the experimental groups; (b) at 10 days post-operative...

Porous hydroxyapatite scaffolds by polymer sponge method

Fooki, A. C B M; Aparecida, A. H.; Fideles, T. B.; Costa, R. C.; Fook, M. V L
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 703-706
Português
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46.4%
This study aimed to develop porous hydroxyapatite scaffold for bone regeneration using the replica of the polymeric sponge technique. Polyurethane sponges were used with varying densities to obtain the scaffolds. The results indicate the porous HA scaffolds developed in this study as potential materials for application as bone substitutes to have high porosity (> 70%), chemical composition, interconnectivity and pore sizes appropriate to the bone regeneration.

Alpha-tricalcium phosphate cement in the reconstruction of bone defects in rats

Pinto,João Gabriel Souza; Primo,Bruno Tochetto; Gassen,Humberto Thomazi; Miguens Júnior,Sérgio Augusto Quevedo; Hernández,Pedro Antonio González; Santos,Luis Alberto dos; Silva Júnior,Aurelício Novaes
Fonte: Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia Publicador: Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2011 Português
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56.45%
PURPOSE: To evaluate the ability of a mixture of α-TCP and autogenous bone (AB) vs. α-TCP alone and AB alone to promote new bone formation and tissue repair in bone defects. METHODS: Bone defects surgically created in 15 male Wistar rats were divided into four groups: Group I (AB), Group II (α-TCP), Group III (α-TCP+AB assessed by light microscopy), and Group IV (α-TCP+AB assessed by scanning electron microscopy). Bone repair findings were assessed at 30, 60, and 120 days postoperatively. RESULTS: The histological findings obtained in Groups I (p=0.459), II (p=0.368), and III (p=0.459) and at 30 days (p=0.717), 60 days (p=0.717), and 120 days (p=0.779) did not show statistically significant differences. Scanning electron microscopy revealed direct contact between the α-TCP+AB implant and the bone tissue at 120 days. CONCLUSION: The α-TCP implant is effective alternative bone substitutes for the treatment of critical size bone defects.

Recent advances in the use of glass ionomers: bone substitutes

SALATA,Luiz Antonio; SVERZUT,Cássio Edvard; XAVIER,Samuel Porfírio
Fonte: Universidade de São Paulo Publicador: Universidade de São Paulo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/1999 Português
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66.42%
The purpose of this study is to update the reader upon the latest scientific trends concerning the use of glass ionomer cements (GICs). These materials which have been found of large clinical application in dentistry worldwide, have recently been successfully tested as bone substitutes in minor surgical procedures. The new perspectives of the use of glass ionomer as an osteoconductive material is analysed in the light of its biological properties as a restorative material.

Morphological and chemical analysis of bone substitutes by scanning electron microscopy and microanalysis by spectroscopy of dispersion energy

Cruz,Gabriela Alessandra da; Toledo,Sérgio de; Sallum,Enilson Antonio; Lima,Antonio Fernando Martorelli de
Fonte: Fundação Odontológica de Ribeirão Preto Publicador: Fundação Odontológica de Ribeirão Preto
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2007 Português
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56.45%
This study evaluated the morphological and chemical composition of the following bone substitutes: cancellous and cortical organic bovine bone with macro and microparticle size ranging from 1.0 to 2.0 mm and 0.25 to 1.0 mm, respectively; inorganic bovine bone with particle size ranging from 0.25 to 1.0 mm; hydroxyapatite with particle size ranging from 0.75 to 1.0 mm; and demineralized freeze-dried bone allograft with particle size ranging from 0.25 to 0.5 mm. The samples were sputter-coated with gold in an ion coater, the morphology was observed and particle size was measured under vacuum by scanning electron microscopy (SEM). The chemical composition was evaluated by spectroscopy of dispersion energy (EDS) microanalysis using samples without coating. SEM analysis provided visual evidence that all examined materials have irregular shape and particle sizes larger than those informed by the manufacturer. EDS microanalysis detected the presence of sodium, calcium and phosphorus that are usual elements of the bone tissue. However, mineral elements were detected in all analyzed particles of organic bovine bone except for macro cancellous organic bovine bone. These results suggest that the examined organic bovine bone cannot be considered as a pure organic material.

An update on bone substitutes for spinal fusion

Miyazaki, Masashi; Tsumura, Hiroshi; Wang, Jeffrey C.; Alanay, Ahmet
Fonte: Springer-Verlag Publicador: Springer-Verlag
Tipo: Artigo de Revista Científica
Português
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46.38%
With the current advances in spinal surgery, an understanding of the precise biological mechanism of each bone substitute is necessary for inducing successful spinal fusion. In this review, the categories of bone substitutes include allografts, ceramics, demineralized bone matrix, osteoinductive factors, autogenous platelet concentrate, mesenchymal stem cells, and gene therapy. Further, clinical studies have been evaluated by their levels of evidence in order to elucidate the precise effect of the bone substitute employed and to establish clinical guidance. This article will review both clinical studies based on evidence and basic research in current advances in order to avoid as far as possible any chances of failure in the future and to understand cellular biology in novel technologies.

Review of Bone Substitutes

Pryor, Landon S.; Gage, Earl; Langevin, Claude-Jean; Herrera, Fernando; Breithaupt, Andrew D.; Gordon, Chad R.; Afifi, Ahmed M.; Zins, James E.; Meltzer, Hal; Gosman, Amanda; Cohen, Steve R.; Holmes, Ralph
Fonte: Thieme Medical Publishers Publicador: Thieme Medical Publishers
Tipo: Artigo de Revista Científica
Publicado em /10/2009 Português
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46.53%
Bone substitutes are being increasingly used in craniofacial surgery and craniomaxillofacial trauma. We will review the history of the biomaterials and describe the ideal characteristics of bone substitutes, with a specific emphasis on craniofacial reconstruction. Some of the most commonly used bone substitutes are discussed in more depth, such as calcium phosphate and hydroxyapatite ceramics and cements, bioactive glass, and polymer products. Areas of active research and future directions include tissue engineering, with an increasing emphasis on bioactivity of the implant.

Clinical, radiological and histological study of the failure of cervical interbody fusions with bone substitutes

Xie, Youzhuan; Chopin, Daniel; Hardouin, Pierre; Lu, Jianxi
Fonte: Springer-Verlag Publicador: Springer-Verlag
Tipo: Artigo de Revista Científica
Português
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46.64%
Few histological studies on bone substitutes in human cervical spine are available and the biological processes of bone substitutes are not well documented. The authors studied four failure cases of cervical interbody fusion: two cases with hydroxyapatite (HA), one case with β-tricalcium phosphate ceramic (β-TCP) and one case with xenograft (bovine bone). Clinical data showed that all the patients experienced neck pain with or without numbness of upper extremity due to fusion failure. Successful fusions were achieved after the salvage surgeries in which autograft were used. Radiographs showed that radiolucent lines were present in all cases. Two HA substitutes fractured without complications. One of them sank into the vertebral body. Some small β-TCP fragments were found under the microscope. Histological study demonstrated only a few newly formed bones at the interface of the substitutes. The fragments of HA were encapsulated by fibrous tissue. The degradation process and bone regeneration were more active in β-TCP than in HA. The intertrabecular spaces of bovine bone were filled with fibrous tissue. The results suggest that a porous calcium phosphate ceramic with special design might assure bone ingrowth and meet the mechanical requirements in cervical interbody fusion. The complications of these materials in the cervical spine should be highlighted.

Divergent Resorbability and Effects on Osteoclast Formation of Commonly Used Bone Substitutes in a Human In Vitro-Assay

Keller, Johannes; Brink, Silja; Busse, Björn; Schilling, Arndt F.; Schinke, Thorsten; Amling, Michael; Lange, Tobias
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 10/10/2012 Português
Relevância na Pesquisa
46.54%
Bioactive bone substitute materials are a valuable alternative to autologous bone transplantations in the repair of skeletal defects. However, clinical studies have reported varying success rates for many commonly used biomaterials. While osteoblasts have traditionally been regarded as key players mediating osseointegration, increasing evidence suggests that bone-resorbing osteoclasts are of crucial importance for the longevity of applied biomaterials. As no standardized data on the resorbability of biomaterials exists, we applied an in vitro-assay to compare ten commonly used bone substitutes. Human peripheral blood mononuclear cells (PBMCs) were differentiated into osteoclasts in the co-presence of dentin chips and biomaterials or dentin alone (control) for a period of 28 days. Osteoclast maturation was monitored on day 0 and 14 by light microscopy, and material-dependent changes in extracellular pH were assessed twice weekly. Mature osteoclasts were quantified using TRAP stainings on day 28 and their resorptive activity was determined on dentin (toluidin blue staining) and biomaterials (scanning electron microscopy, SEM). The analyzed biomaterials caused specific changes in the pH, which were correlated with osteoclast multinuclearity (r = 0.942; p = 0.034) and activity on biomaterials (r = 0.594; p = 0.041). Perossal led to a significant reduction of pH...

Bone grafts, bone substitutes and orthobiologics: The bridge between basic science and clinical advancements in fracture healing

Roberts, Timothy T.; Rosenbaum, Andrew J.
Fonte: Landes Bioscience Publicador: Landes Bioscience
Tipo: Artigo de Revista Científica
Publicado em 01/10/2012 Português
Relevância na Pesquisa
46.51%
The biology of fracture healing is better understood than ever before, with advancements such as the locking screw leading to more predictable and less eventful osseous healing. However, at times one’s intrinsic biological response, and even concurrent surgical stabilization, is inadequate. In hopes of facilitating osseous union, bone grafts, bone substitutes and orthobiologics are being relied on more than ever before. The osteoinductive, osteoconductive and osteogenic properties of these substrates have been elucidated in the basic science literature and validated in clinical orthopaedic practice. Furthermore, an industry built around these items is more successful and in demand than ever before. This review provides a comprehensive overview of the basic science, clinical utility and economics of bone grafts, bone substitutes and orthobiologics.

Physicochemical Characteristics of Bone Substitutes Used in Oral Surgery in Comparison to Autogenous Bone

Berberi, Antoine; Samarani, Antoine; Nader, Nabih; Noujeim, Ziad; Dagher, Maroun; Kanj, Wasfi; Mearawi, Rita; Salemeh, Ziad; Badran, Bassam
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
46.56%
Bone substitutes used in oral surgery include allografts, xenografts, and synthetic materials that are frequently used to compensate bone loss or to reinforce repaired bone, but little is currently known about their physicochemical characteristics. The aim of this study was to evaluate a number of physical and chemical properties in a variety of granulated mineral-based biomaterials used in dentistry and to compare them with those of autogenous bone. Autogenous bone and eight commercial biomaterials of human, bovine, and synthetic origins were studied by high-resolution X-ray diffraction, atomic absorption spectrometry, and laser diffraction to determine their chemical composition, calcium release concentration, crystallinity, and granulation size. The highest calcium release concentration was 24. 94 mg/g for Puros and the lowest one was 2.83 mg/g for Ingenios β-TCP compared to 20.15 mg/g for natural bone. The range of particles sizes, in terms of median size D50, varied between 1.32 μm for BioOss and 902.41 μm for OsteoSponge, compared to 282.1 μm for natural bone. All samples displayed a similar hexagonal shape as bone, except Ingenios β-TCP, Macrobone, and OsteoSponge, which showed rhomboid and triclinic shapes...

Bone substitutes in orthopaedic surgery: from basic science to clinical practice

Campana, V.; Milano, G.; Pagano, E.; Barba, M.; Cicione, C.; Salonna, G.; Lattanzi, W.; Logroscino, G.
Fonte: Springer US Publicador: Springer US
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
46.69%
Bone substitutes are being increasingly used in surgery as over two millions bone grafting procedures are performed worldwide per year. Autografts still represent the gold standard for bone substitution, though the morbidity and the inherent limited availability are the main limitations. Allografts, i.e. banked bone, are osteoconductive and weakly osteoinductive, though there are still concerns about the residual infective risks, costs and donor availability issues. As an alternative, xenograft substitutes are cheap, but their use provided contrasting results, so far. Ceramic-based synthetic bone substitutes are alternatively based on hydroxyapatite (HA) and tricalcium phosphates, and are widely used in the clinical practice. Indeed, despite being completely resorbable and weaker than cortical bone, they have exhaustively proved to be effective. Biomimetic HAs are the evolution of traditional HA and contains ions (carbonates, Si, Sr, Fl, Mg) that mimic natural HA (biomimetic HA). Injectable cements represent another evolution, enabling mininvasive techniques. Bone morphogenetic proteins (namely BMP2 and 7) are the only bone inducing growth factors approved for human use in spine surgery and for the treatment of tibial nonunion. Demineralized bone matrix and platelet rich plasma did not prove to be effective and their use as bone substitutes remains controversial. Experimental cell-based approaches are considered the best suitable emerging strategies in several regenerative medicine application...

Development and mechanical characterization of porous titanium bone substitutes

BARBAS, Alexandre; BONNET, Anne-Sophie; LIPINSKI, Paul; PESCI, Raphaël; DUBOIS, Guillaume
Fonte: Elsevier Publicador: Elsevier
Português
Relevância na Pesquisa
46.38%
The authors wish to thank Dr J.-M. Hiver from Institut Jean Lamour, Ecole des Mines de Nancy for his participation in the computed tomography analysis of the porous samples; Commercially Pure Porous Titanium (CPPTi) can be used for surgical implants to avoid the stress shielding effect due to the mismatch between the mechanical properties of titanium and bone. Most researchers in this area deal with randomly distributed pores or simple architectures in titanium alloys. The control of porosity, pore size and distribution is necessary to obtain implants with mechanical properties close to those of bone and to ensure their osseointegration. The aim of the present work was therefore to develop and characterize such a specific porous structure. First of all, the properties of titanium made by Selective Laser Melting (SLM) were characterized through experimental testing on bulk specimens. An elementary pattern of the porous structure was then designed to mimic the orthotropic properties of the human bone following several mechanical and geometrical criteria. Finite Element Analysis (FEA) was used to optimize the pattern. A porosity of 53% and pore sizes in the range of 860 to 1500 μm were finally adopted. Tensile tests on porous samples were then carried out to validate the properties obtained numerically and identif the failure modes of the samples. Finally...

Hydroxyapatite formation on metallurgical grade porous silicon nanosponge particles

Chadwick, E.G; Clarkin, O.M; Tanner, D.A
Fonte: Nova Science Publishers Publicador: Nova Science Publishers
Tipo: info:eu-repo/semantics/bookPart; all_ul_research; ul_published_reviewed
Português
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46.56%
peer-reviewed; Investigations into the development of potential bone substitutes have increased rapidly in the last decade. Titanium and cobalt chrome are currently the alloys of choice when it comes to the orthopedic medical device fields due to their excellent mechanical strength and corrosion-resistant properties. Yet these materials are unable to elicit a biologically functional bone-material interface without a bioactive surface coating or surface modification. Osteoconductivity is only achieved when suitable coatings are applied or their surface properties are suitably altered. The need for significant bony reconstruction implants as a result of prosthetic revision surgery also increases the need to produce longer lasting or permanent bone substitute materials. Hydroxyapatite is the principle constituent of bone and has been used as a mechanism to induce bone formation at particular biological sites in need of bone repair and growth. When applied as a surface coating, hydroxyapatite s chemical and physical properties allow osteointegration of medical devices and prostheses. The discovery of hydroxyapatite has resulted, not only in rapid advances and developments in the orthopedic and dental fields, but has also lead to a surge in investigations into further tailoring of the material to create new devices that meet clinical needs. Currently...

Validity of synthetic bone as a substitute for osteoporotic cadaveric femoral heads in mechanical testing: a biomechanical study

O'Neill, F; Condon, F; McGloughlin, Timothy M.; Lenehan, B; Coffey, Calvin J; Walsh, Michael T.
Fonte: British Editorial Society of Bone and Joint Surgery Publicador: British Editorial Society of Bone and Joint Surgery
Tipo: info:eu-repo/semantics/article; all_ul_research; ul_published_reviewed
Português
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56.24%
peer-reviewed; IntroductionThe objective of this study was to determine if a synthetic bone substitute would provide results similar to bone from osteoporotic femoral heads during in vitro testing with orthopaedic implants. If the synthetic material could produce results similar to those of the osteoporotic bone, it could reduce or eliminate the need for testing of implants on bone.MethodsPushout studies were performed with the dynamic hip screw (DHS) and the DHS Blade in both cadaveric femoral heads and artificial bone substitutes in the form of polyurethane foam blocks of different density. The pushout studies were performed as a means of comparing the force displacement curves produced by each implant within each material.ResultsThe results demonstrated that test material with a density of 0.16 g/cm(3) (block A) produced qualitatively similar force displacement curves for the DHS and qualitatively and quantitatively similar force displacement curves for the DHS Blade, whereas the test material with a density of 0.08 g/cm(3) (block B) did not produce results that were predictive of those recorded within the osteoporotic cadaveric femoral heads.ConclusionThis study demonstrates that synthetic material with a density of 0.16 g/cm(3) can provide a good substitute for cadaveric osteoporotic femoral heads in the testing of implants. However we do recognise that no synthetic material can be considered as a definitive substitute for bone...