No description available.

No description available.

No description available.

Hydroxyapatite (HA) is a highly biocompatible calcium phosphate which closely resembles the mineral component of bone. Porous structures composed of biocompatible materials are believed to enhance fixation (and integration) as they encourage the ingrowth of bone into the implant. Consequently there is great interest in the potential of porous HA as an alternative to bone homo grafts and auto grafts. However, despite the interest in the field, there has been no thorough investigation into the physical and structural properties of porous HA and their effects on bone ingrowth. The material used in this study was a carbonated apatite (containing < 0.9 % levels of trace element impurities) with a trabecular macrostructure, that had been converted from bovine cancellous bone. The apparent density of the material ranged from 0.35 -1.45 g.cm-3 and the macrostructural morphology varied from an open equiaxed foam to a columnar honeycomb-like structure. The ultimate compressive stress was strongly related (r = 0.9) to the square of the apparent density, while compressive modulus was influenced by both apparent density and macrostructural morphology. Transmission electron microscopy of human osteoblast-like cells cultured on the material demonstrated that cells were closely associated with the surface. Specimens with densities of 0.6.0.9 and 1.2 g.cm-3 were then implanted in a lapine cancellous site for periods of 10 days, 3, 5, 13 and 26 weeks. After implantation all specimens elicited a highly biocompatible response, with active areas of bone deposition, remodelling and revascularization and no fibrous encapsulation. The amount of bone ingrowth within the implant (25-10%) after.5 weeks was found to vary with apparent density (0.6-1.2 g.cm-3) indicating that osseointegration was a function of macrostructural morphology. Pushout testing of retrieved spedmens indicated that all implants were securely fixed by 5 weeks (2-3 MPa). Compression testing demonstrated that after 5 weeks low density implants were sufficiently reinforced by bone ingrowth to equal the compressive strength of the host tissue (6 MPa) which increased to approximately 20 MPa at 3 and 6 months.

A compreensão dos fenômenos de reparo ósseo representa parte fundamental da odontologia e da cirurgia bucomaxilofacial. Objetivo: O presente trabalho tem como objetivo avaliar a influência da estimulação de campo magnético sepultado sobre o reparo ósseo em calvária de ratos após reconstrução com enxerto ósseo autógeno, implante de hidroxiapatita granulada sintética ou enxerto alógeno de cartilagem, comparados entre si e aos controles sem estimulação magnética. Materiais e métodos: foram utilizados 95 ratos Wistar machos, divididos em grupos constituidos por 5 animais. Foram realizados defeitos ósseos críticos na calvária dos animais, sendo os mesmos imediatamente reconstruídos, isoladamente com, enxerto ósseo autógeno, hidroxiapatita granulada sintética e enxerto alógeno de cartilagem, sob influência ou não de campos magnéticos sepultados. Foram realizadas avaliações aos 15, 30 e 60 dias pós-operatórios. Apenas um grupo não sofreu intervenção cirúrgica (Naive), para fornecer os dados para obtenção da atividade fisiológica das enzimas fosfatase alcalina e fosfatase ácida. Em todos os tempos experimentais foi realizada a quantificação da neoformação óssea por meio da histomorfometria. A avaliação da intensidade de expressão da proteína osteopontina, foi obtida somente aos 60 dias Resultados: a avaliação histomorfométrica evidenciou interação significativa entre grupos e tempos com p=0,008. Aos 60 dias, nos animais que receberam reconstrução com osso autógeno o grupo sob influência do campo magnético apresentou percentual de preenchimento ósseo superior ao grupo sem influência do estímulo magnético. A mensuração da atividade das enzimas fosfatase alcalina e fosfatase ácida evidenciou interação significativa entre grupos e tempos com p=0,02 e p=0,005 respectivamente. Aos 60 dias, todos os grupos apresentaram atividade de ambas enzimas significativamente inferior ao grupo Naive. A análise imunoistoquímica realizada não evidenciou diferença significativa na expressão da enzima osteopontina com a metodologia empregada. Conclusão: o presente trabalho contribuiu para o entendimento da influência do campo magnético sepultado sobre o reparo ósseo em crânio de rato. A partir dos resultados encontrados, novas metodologias podem ser propostas para complementar os resultados obtidos e fortalecer a presente linha de pesquisa. / Objective: the comprehension of the phenomenon of bone repair represents a fundamental part of dentistry and of oral and maxillofacial surgery. The present work has as its objective, to evaluate the influence of a stimulated magnetic field implanted on the calvarial bone of rats after its reconstruction with autogeneous bone graft, synthetic hydroxyapatite crystals or with the insertion of allogeneic cartilage, in comparison to no magnetic stimulation. Materials e methods: 95 Wistar male rats were used, divided into groups with 5 animals in each. The autogeneous bone graft, the synthetic hydroxyapatite crystals and the insertion of allogeneic cartilage were each used separately in the performed interventions of reconstruction with or without the influence of implanted magnetic fields. Evaluations were performed in 15, 30 and 60 days after surgery. Only one group did not suffer surgical intervention (Naïve); this group provided data for the physiological activity of the alkaline and acid phosphatase enzymes. Also, quantification of bone neoformation was obtained through histomorphometry in all experimental time periods, and evaluation of the osteopontin protein expression of intensity in 60 days. Results: the histomorphometry 60-day evaluation, showed evidence of a significant interaction between the groups and the time of p=0,008 on the animals that received reconstruction with autogeneous bone. The group that was influenced by the magnetic field presented a percent of bone reconstruction superior to that of the group which did not receive magnetic stimulation. In 60 days, activity mensuration of the alkaline and acid phosphatase enzymes, showed evidence of significant interaction between the groups and the times of p=0,02 and p=0,005, respectively. In all groups, activity of both enzymes was present and significantly inferior to the Naive group. The immunohistochemistry analysis performed did not show evidence of any significant difference in the oseopontin enzyme expression with the applied methodology. Conclusion: this work contributed to the understanding of the influence that an implanted magnetic field has on bone reconstruction. From the results found, new methodologies can be proposed as a complementary to obtained results and can strengthen the present line of research.

A compreensão dos fenômenos de reparo ósseo representa parte fundamental da odontologia e da cirurgia bucomaxilofacial. Objetivo: O presente trabalho tem como objetivo avaliar a influência da estimulação de campo magnético sepultado sobre o reparo ósseo em calvária de ratos após reconstrução com enxerto ósseo autógeno, implante de hidroxiapatita granulada sintética ou enxerto alógeno de cartilagem, comparados entre si e aos controles sem estimulação magnética. Materiais e métodos: foram utilizados 95 ratos Wistar machos, divididos em grupos constituidos por 5 animais. Foram realizados defeitos ósseos críticos na calvária dos animais, sendo os mesmos imediatamente reconstruídos, isoladamente com, enxerto ósseo autógeno, hidroxiapatita granulada sintética e enxerto alógeno de cartilagem, sob influência ou não de campos magnéticos sepultados. Foram realizadas avaliações aos 15, 30 e 60 dias pós-operatórios. Apenas um grupo não sofreu intervenção cirúrgica (Naive), para fornecer os dados para obtenção da atividade fisiológica das enzimas fosfatase alcalina e fosfatase ácida. Em todos os tempos experimentais foi realizada a quantificação da neoformação óssea por meio da histomorfometria. A avaliação da intensidade de expressão da proteína osteopontina, foi obtida somente aos 60 dias Resultados: a avaliação histomorfométrica evidenciou interação significativa entre grupos e tempos com p=0,008. Aos 60 dias, nos animais que receberam reconstrução com osso autógeno o grupo sob influência do campo magnético apresentou percentual de preenchimento ósseo superior ao grupo sem influência do estímulo magnético. A mensuração da atividade das enzimas fosfatase alcalina e fosfatase ácida evidenciou interação significativa entre grupos e tempos com p=0,02 e p=0,005 respectivamente. Aos 60 dias, todos os grupos apresentaram atividade de ambas enzimas significativamente inferior ao grupo Naive. A análise imunoistoquímica realizada não evidenciou diferença significativa na expressão da enzima osteopontina com a metodologia empregada. Conclusão: o presente trabalho contribuiu para o entendimento da influência do campo magnético sepultado sobre o reparo ósseo em crânio de rato. A partir dos resultados encontrados, novas metodologias podem ser propostas para complementar os resultados obtidos e fortalecer a presente linha de pesquisa. / Objective: the comprehension of the phenomenon of bone repair represents a fundamental part of dentistry and of oral and maxillofacial surgery. The present work has as its objective, to evaluate the influence of a stimulated magnetic field implanted on the calvarial bone of rats after its reconstruction with autogeneous bone graft, synthetic hydroxyapatite crystals or with the insertion of allogeneic cartilage, in comparison to no magnetic stimulation. Materials e methods: 95 Wistar male rats were used, divided into groups with 5 animals in each. The autogeneous bone graft, the synthetic hydroxyapatite crystals and the insertion of allogeneic cartilage were each used separately in the performed interventions of reconstruction with or without the influence of implanted magnetic fields. Evaluations were performed in 15, 30 and 60 days after surgery. Only one group did not suffer surgical intervention (Naïve); this group provided data for the physiological activity of the alkaline and acid phosphatase enzymes. Also, quantification of bone neoformation was obtained through histomorphometry in all experimental time periods, and evaluation of the osteopontin protein expression of intensity in 60 days. Results: the histomorphometry 60-day evaluation, showed evidence of a significant interaction between the groups and the time of p=0,008 on the animals that received reconstruction with autogeneous bone. The group that was influenced by the magnetic field presented a percent of bone reconstruction superior to that of the group which did not receive magnetic stimulation. In 60 days, activity mensuration of the alkaline and acid phosphatase enzymes, showed evidence of significant interaction between the groups and the times of p=0,02 and p=0,005, respectively. In all groups, activity of both enzymes was present and significantly inferior to the Naive group. The immunohistochemistry analysis performed did not show evidence of any significant difference in the oseopontin enzyme expression with the applied methodology. Conclusion: this work contributed to the understanding of the influence that an implanted magnetic field has on bone reconstruction. From the results found, new methodologies can be proposed as a complementary to obtained results and can strengthen the present line of research.

A compreensão dos fenômenos de reparo ósseo representa parte fundamental da odontologia e da cirurgia bucomaxilofacial. Objetivo: O presente trabalho tem como objetivo avaliar a influência da estimulação de campo magnético sepultado sobre o reparo ósseo em calvária de ratos após reconstrução com enxerto ósseo autógeno, implante de hidroxiapatita granulada sintética ou enxerto alógeno de cartilagem, comparados entre si e aos controles sem estimulação magnética. Materiais e métodos: foram utilizados 95 ratos Wistar machos, divididos em grupos constituidos por 5 animais. Foram realizados defeitos ósseos críticos na calvária dos animais, sendo os mesmos imediatamente reconstruídos, isoladamente com, enxerto ósseo autógeno, hidroxiapatita granulada sintética e enxerto alógeno de cartilagem, sob influência ou não de campos magnéticos sepultados. Foram realizadas avaliações aos 15, 30 e 60 dias pós-operatórios. Apenas um grupo não sofreu intervenção cirúrgica (Naive), para fornecer os dados para obtenção da atividade fisiológica das enzimas fosfatase alcalina e fosfatase ácida. Em todos os tempos experimentais foi realizada a quantificação da neoformação óssea por meio da histomorfometria. A avaliação da intensidade de expressão da proteína osteopontina, foi obtida somente aos 60 dias Resultados: a avaliação histomorfométrica evidenciou interação significativa entre grupos e tempos com p=0,008. Aos 60 dias, nos animais que receberam reconstrução com osso autógeno o grupo sob influência do campo magnético apresentou percentual de preenchimento ósseo superior ao grupo sem influência do estímulo magnético. A mensuração da atividade das enzimas fosfatase alcalina e fosfatase ácida evidenciou interação significativa entre grupos e tempos com p=0,02 e p=0,005 respectivamente. Aos 60 dias, todos os grupos apresentaram atividade de ambas enzimas significativamente inferior ao grupo Naive. A análise imunoistoquímica realizada não evidenciou diferença significativa na expressão da enzima osteopontina com a metodologia empregada. Conclusão: o presente trabalho contribuiu para o entendimento da influência do campo magnético sepultado sobre o reparo ósseo em crânio de rato. A partir dos resultados encontrados, novas metodologias podem ser propostas para complementar os resultados obtidos e fortalecer a presente linha de pesquisa. / Objective: the comprehension of the phenomenon of bone repair represents a fundamental part of dentistry and of oral and maxillofacial surgery. The present work has as its objective, to evaluate the influence of a stimulated magnetic field implanted on the calvarial bone of rats after its reconstruction with autogeneous bone graft, synthetic hydroxyapatite crystals or with the insertion of allogeneic cartilage, in comparison to no magnetic stimulation. Materials e methods: 95 Wistar male rats were used, divided into groups with 5 animals in each. The autogeneous bone graft, the synthetic hydroxyapatite crystals and the insertion of allogeneic cartilage were each used separately in the performed interventions of reconstruction with or without the influence of implanted magnetic fields. Evaluations were performed in 15, 30 and 60 days after surgery. Only one group did not suffer surgical intervention (Naïve); this group provided data for the physiological activity of the alkaline and acid phosphatase enzymes. Also, quantification of bone neoformation was obtained through histomorphometry in all experimental time periods, and evaluation of the osteopontin protein expression of intensity in 60 days. Results: the histomorphometry 60-day evaluation, showed evidence of a significant interaction between the groups and the time of p=0,008 on the animals that received reconstruction with autogeneous bone. The group that was influenced by the magnetic field presented a percent of bone reconstruction superior to that of the group which did not receive magnetic stimulation. In 60 days, activity mensuration of the alkaline and acid phosphatase enzymes, showed evidence of significant interaction between the groups and the times of p=0,02 and p=0,005, respectively. In all groups, activity of both enzymes was present and significantly inferior to the Naive group. The immunohistochemistry analysis performed did not show evidence of any significant difference in the oseopontin enzyme expression with the applied methodology. Conclusion: this work contributed to the understanding of the influence that an implanted magnetic field has on bone reconstruction. From the results found, new methodologies can be proposed as a complementary to obtained results and can strengthen the present line of research.

Metal implants are a type of hard tissue replacement currently used. Metals used for implants include: stainless steel, titanium, chrome, and cobalt alloys. Such implants often fail at the interface with bone. Metal implants fail when the surface of the implant is coated with an osteoconductive material. An osteoconductive material provides scaffolding for cellular migration, cellular attachment, and cellular distribution. A reason for metal implant failure could be the vastly different material properties than bone. Motivation for the research was to find a suitable bone substitute other than metal. Materials considered were: zirconia toughened alumina, carbon fiber reinforced epoxy, and glass fiber reinforced epoxy. Those materials have been used in previous biological applications and can be cast into complex configurations. Objectives of the study were to compare material properties of the composites to bone. A method to create porosity was then tested in the material that was similar to bone in critical material property. Some of the materials were statistically similar to bone in yield strength. Method to create interconnected porosity in those materials resulted in 49% void space.

Die Regeneration und Rekonstruktion von Knochendefekten stellt eine klinische Herausforderung dar. Überschreitet ein knöcherner Defekt eine kritische Größe, ist das Regenerationsvermögen des Körpers nicht ausreichend, um den Defekt vollständig mit Knochengewebe zu schließen. Um das Einwachsen von Bindegewebe und den Verlust der Stützfunktion des Knochens zu verhindern, ist es notwendig, einen solchen Defekt mit einem Knochenersatzmaterial zu versorgen. Bei Patienten mit einer systemischen Skeletterkrankung, wie Osteoporose, liegen erschwerte Bedingungen für den Heilungsprozess vor. Osteoporose bedingt ist die Remodellierung des Knochens beeinträchtigt. Dies äußert sich in einer verzögerten Knochenheilung sowie in einer veränderten Knochenarchitektur und entstehenden Mikrofrakturen. Die Kombination aus der Fragilität des osteoporotischen Knochens und einer altersbedingten erhöhten Sturzgefahr resultiert in einem mit zunehmendem Alter steigenden Frakturrisiko. Knochendefekte und pathologische Frakturen, die Patienten im Verlauf einer postmenopausalen oder altersbedingten Osteoporose entwickeln, betreffen häufig die Wirbelsäule oder den Schenkel-hals. Die nur langsam oder nahezu nicht heilenden Frakturen gehen nicht nur mit Schmerzen einher, sondern schränken die Patienten auch funktionell in ihrem Alltag ein und können zur Pflegebedürftigkeit und Bettlägerigkeit führen. Die medizinische Versorgung solcher Defekte und Frakturen mit geeigneten Knochenersatzmaterialien ist nicht nur eine klinische, sondern eine interdisziplinäre Problemstellung.

The present work deals with the comparison of the properties of metallic biomaterials in terms of their suitability for use as a temporary metal implant. In the work is judged biocompatibility of materials, they are comparing the corrosion rates and the influence of additives in the iron alloy to change biocompatibility and corrosion rate. In a part of this work is suggesting a method of preparing biodegradable metallic samples with different alloying elements and determine the methods, processes and measuring the corrosion rates. Part of this work is the chapter dealing with the function and effect of iron in the human body and any complications that may occur when a surplus caused by the release of part of the implant during its degradation or corrosion products. The outcome of this work is sort of created an iron-based samples in terms of their electrochemical corrosion potential, corrosion rate of samples exposed in various corrosive solutions, spectroscopic elemental analysis and outputs from the microscopic observation of the structures.