Fabiana Paim Rosa

Histomorphometric Analysis of Tissue Responses to Bioactive Glass Implants in Critical Defects in Rat Calvaria

The aim of this study was to evaluate the osteogenic behavior of two chemically similar bioactive glass products (Biogran®and Perioglas®) implanted in critical bone defects in rat calvaria. Thirty-six transfixed bone defects of 8 mm diameter were made surgically in adult male Wistar rats. The animals were distributed equally into three groups: Biogran (GI), Perioglas (GII) and without implant material (control; GIII). The morphology and composition of both bioactive glasses were analyzed by scanning electron microscopy and energy-dispersive spectrometry. Tissue specimens were analyzed at the biological time points of 15, 30 and 60 days by optical microscopy and morphometry, demonstrating biocompatibility for the tested materials with moderate chronic inflammation involving their particles. Bone neoformation resulted only as a reparative reaction to an intentionally produced defect and was limited to the defect’s edges. No statistically significant differences among the groups were observed. At the scar interstice, abundant deposits of collagenous fibers enveloping the particles were noted. The present results indicated that the bioactive glasses, under the experimental conditions analyzed, did not show osteogenic behavior.

Ultrastructure of regenerated bone mineral surrounding hydroxyapatite–alginate composite and sintered hydroxyapatite

We report the ultrastructure of regenerated bone surrounding two types of biomaterials: hydroxyapatite-alginate composite and sintered hydroxyapatite. Critical defects in the calvaria of Wistar rats were filled with micrometer-sized spherical biomaterials and analyzed after 90 and 120 days of implantation by high-resolution transmission electron microscopy and Fourier transform infrared attenuated total reflectance microscopy, respectively. Infrared spectroscopy showed that hydroxyapatite of both biomaterials became more disordered after implantation in the rat calvaria, indicating that the biological environment induced modifications in biomaterials structure. We observed that the regenerated bone surrounding both biomaterials had a lamellar structure with type I collagen fibers alternating in adjacent lamella with angles of approximately 90°. In each lamella, plate-like apatite crystals were aligned in the c-axis direction, although a rotation around the c-axis could be present. Bone plate-like crystal dimensions were similar in regenerated bone around biomaterials and pre-existing bone in the rat calvaria. No epitaxial growth was observed around any of the biomaterials. A distinct mineralized layer was observed between new bone and hydroxyapatite-alginate biomaterial. This region presented a particular ultrastructure with crystallites smaller than those of the bulk of the biomaterial, and was possibly formed during the synthesis of alginate-containing composite or in the biological environment after implantation. Round nanoparticles were observed in regions of newly formed bone. The findings of this work contribute to a better understanding of the role of hydroxyapatite based biomaterials in bone regeneration processes at the nanoscale.

Analysis of Bone Repair Tissue after Implantation of Biomaterials and Application of Vibratory Waves

Bone tissue in ideal conditions morphofunctional remodeling properly. The bone can be affected by fractures, tumors, hormonal dysfunction, senescence, genetic modifications, among others. In such circumstances, the proper diet, drug use, exercise and other factors are important to the prevention of bone mineral loss. The effect of kinesiotherapy obtained through the application of vibratory waves administered through the vibrating platform, Juvent1000 ® already been established in the prevention of bone mineral density, muscular trophism, among other systems in humans. The response by analyzing bone tissue of bone repair in critical defect is not known in experimental animals and in human clinical. This research evaluated the osteogenic potential critical defect in the calvaria of rats subjected to the application of vibratory waves obtained by vibrating platform and implant in the critical defect of rat calvaria. The bone tissue response was evaluated showed satisfactory results obtained in biological points 15, 45 and 120 days.

Arcabouços de Quitosana - Propriedades Físico-Químicas e Biológicas para o Reparo Ósseo

A quitosana e um polimero versatil, cuja aplicabilidade no reparo osseo tem sido amplamente investigada. As principais propriedades biologicas desse polimero estao relacionadas a sua biocompatibilidade, a degradacao lenta e a biorreabsorcao controlada. Apresenta tambem bioatividade na inducao ou estimulacao de osteoblastos, acao antimicrobiana, antifungica, hemostatica e angiogenica. Em razao de suas caracteristicas, podem integrar a sua estrutura os polieletrolitos anionicos, os polimeros e proteinas, o que possibilita a obtencao de diferentes biomateriais com propriedades, aplicacoes e formas de apresentacao distintas. Quando utilizada sob a forma de matriz tridimensional (3D), atua como arcabouco fisico para a regeneracao tecidual, pela migracao, adesao e proliferacao das celulas osseas. Sua estrutura polimerica e seus atributos fisico-quimicos permitem o aprimoramento de suas propriedades bioativas por meio da adicao de compositos, celulas ou fatores de crescimento. E assim, na medida em que ha aprimoramento na microestrutura molecular da quitosana, ha modificacoes nas suas propriedades como biomaterial de referencia na bioengenharia tecidual ossea. Dentre as caracteristicas modificaveis desses biomateriais a base de quitosana, destacam-se a resistencia mecânica, topografia superficial, hidrofilia, elasticidade, porosidade, interconectividade, biodegradacao, massa molar e seu pH. Este trabalho, portanto, tem como objetivo abordar os principais aspectos, micro e macroestruturais, relativos a estrutura da quitosana no reparo tecidual osseo, assim como seu impacto sobre o comportamento biologico de matrizes tridimensionais, quando utilizadas de forma isolada ou associadas a outros biomateriais na medicina regenerativa. Palavras-chave : quitosana, biomaterial, Bioengenharia Tecidual, reparo osseo, matriz tridimensional, arcabouco. A quitosana e um polimero versatil, cuja aplicabilidade no reparo osseo tem sido amplamente investigada. As principais propriedades biologicas desse polimero estao relacionadas a sua biocompatibilidade, a degradacao lenta e a biorreabsorcao controlada. Apresenta tambem bioatividade na inducao ou estimulacao de osteoblastos, acao antimicrobiana, antifungica, hemostatica e angiogenica. Em razao de suas caracteristicas, podem integrar a sua estrutura os polieletrolitos anionicos, os polimeros e proteinas, o que possibilita a obtencao de diferentes biomateriais com propriedades, aplicacoes e formas de apresentacao distintas. Quando utilizada sob a forma de matriz tridimensional (3D), atua como arcabouco fisico para a regeneracao tecidual, pela migracao, adesao e proliferacao das celulas osseas. Sua estrutura polimerica e seus atributos fisico-quimicos permitem o aprimoramento de suas propriedades bioativas por meio da adicao de compositos, celulas ou fatores de crescimento. E assim, na medida em que ha aprimoramento na microestrutura molecular da quitosana, ha modificacoes nas suas propriedades como biomaterial de referencia na bioengenharia tecidual ossea. Dentre as caracteristicas modificaveis desses biomateriais a base de quitosana, destacam-se a resistencia mecânica, topografia superficial, hidrofilia, elasticidade, porosidade, interconectividade, biodegradacao, massa molar e seu pH. Este trabalho, portanto, tem como objetivo abordar os principais aspectos, micro e macroestruturais, relativos a estrutura da quitosana no reparo tecidual osseo, assim como seu impacto sobre o comportamento biologico de matrizes tridimensionais, quando utilizadas de forma isolada ou associadas a outros biomateriais na medicina regenerativa. Palavras-chave : quitosana, biomaterial, Bioengenharia Tecidual, reparo osseo, matriz tridimensional, arcabouco.

Characterization of Biomaterial and Tissue Response Analysis after Implantation

Some biomaterials can be used to promote tissue repair process. The biological substitutes (biomaterials such as hydroxyapatite beads) can be used with some advantages and purpose of mimicking responses to on-site repair of the injured bone. The objective of this study was to evaluate the osteogenic potential of the biomaterial composed of hydroxyapatite and alginate in place of the critical defect. bioceramic samples stoichiometric hydroxyapatite was produced by the precipitation method, wet method with ion molar ratio of Ca 10 (PO 4) 6 (OH) 2, in which the Ca / P ratio was equal to 1.67. The reaction conditions were favorable to the composition of a biomaterial with crystalline phase. The synthesis of the biomaterial composed of hydroxyapatite and alginate microspheres (HAAlg5%; 200 ø 425mm) was obtained from two primary solutions with the aim of, in optimal reactive conditions, to form the precipitate. After synthesis the microspheres were implanted into the defect site. The potential effects of using HAAlg5% and the application of vibratory waves in the critical defect repair were unknown and the results described in this study are promising, considering the systemic therapy and at the site of injury. The biomaterial used promoted repair the injured tissue.