The primary events occurring in vivo after implant placement are very important in achieving osseointegration. The objective of this research study was to investigate these primary processes and its variations with different surface treatments of titanium. This may further aid in finding surface characteristics which have a positive effect on osseointegration. Firstly, ion adsorption from a physiological solution and ion and protein adsorption from a simulated in vivo environment to polished, glass bead blasted and alkali etched + heat-treated titanium surfaces were tested with the aid of x-ray photoelectron spectroscopy. Secondly, the adhesion strength of bone cells to the 3 different titanium surfaces in two force directions (normal and tangential to the surface) was assessed with the aid of centrifugal accelerations. The theory here was that ions are adsorbed first to the surfaces, proteins then bind to the ions, and then cells can bind to the RGD sequence in certain proteins. Calcium (Ca) and phosphorus (P) were found to be adsorbed to all titanium surfaces from the physiological solution to varying degrees, however, only trace levels of Ca and P could be detected on all surfaces after exposure to a simulated in vivo environment, instead large amounts of protein were found. Bone cell adhesion strength was found to vary (between < 2 x 10-8 N and 8 x 10-8 N) statistically significant (p < 0.001 - p < 0.05) with surface treatment and force direction. Conclusion: although the surfaces exhibited different responses for individual factors of ion adsorption, protein adsorption or cell adhesion, on balance for all three factors the performance of glass bead blasted titanium surfaces showed the most positive results.

Thesis (M.S.)--University of Michigan, 2002. / Includes bibliographical references.

Titanium and its alloys have been widely used as materials in biomedicine and in particular, for dental implants, and one main reason is their unique ability to osseointegrate with the host bone. This phenomenon forms a strong bone-to-implant bonding. The rate and quality of osseointegration of a titanium dental implant depends heavily upon its surface properties. Over time, various surface treatment methods have been developed to further improve osseointegration of titanium-based biomaterials. This PhD thesis focuses on promising surface treatment methodology: surface charge modification. A negative charge has been known to promote the osseointegration of titanium biomaterials. Before the current work there was no practical approach to induce negative charge on titanium surfaces. The goal was to find such a practical technique. The current investigations revealed that sandblasting, a commonly used surface treatment method, can generate a negative charge on the surface of titanium, and also titanium alloy and stainless steel micro-implants, due to the triboelectric effect. Stainless steel doesn’t osseointegrate. The basic methodology of these studies was to sandblast titanium and measure the amount and polarity of the static charge on titanium surfaces. The effects of several important parameters were evaluated, including the sandblasting material, the size of the blasting grits, and the shape of the titanium material. Statistical analysis was performed on the results of the static charge measurements. In addition, the contamination of the titanium sandblasting was also evaluated. The results of the current studies suggested that sandblasting could generate static charges on titanium and stainless steel surfaces. However, such charges gradually dissipate into the atmosphere. The amount, polarity, and the decay rate of the charge depend on many factors tested in the experiments. These results might explain the beneficial of sandblasting on the osseointegration of titanium implants. Osseointegration has been traditionally attributed to its roughening effects. Moreover, the current studies may potentially lead to improved sandblasting techniques, becoming in mind that more research should be carried out. / published_or_final_version / Dentistry / Doctoral / Doctor of Philosophy

abstract / Dentistry / Doctoral / Doctor of Philosophy

Thesis (MTech. degree in Pharmaceutical Sciences.)--Tshwane University of Technology, 2010. / Aims to determine the biochemical and histological parameter of bone formed heterotopically in the rodent bioassay osteoinduction model, of enzymatically and chemically treated xenogeneic insoluble collagenous bone matrix (ICBM) loaded with porcine BMP complex, purified according to a proprietary high yield purification procedure.

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (leaves 170-181).

Orientador: Daniele Botticelli / Banca: Wilson Roberto Poi / Banca: Idelmo Rangel Garcia Júnior / Banca: Luiz Antônio Salata / Banca: Thaís da Silveira Rodrigues / Resumo: Objetivo: avaliar a regeneração da crista óssea alveolar e o processo de osseointegração de implantes instalados em sítios enxertados com blocos de osso autógeno e osso bovino mineral (DBBM),associado a membrana de colágeno. Material e método: em 6 cães labradores foram extraidos os molares inferiores bilateralmente, nos quais foi removida a tábua óssea vestibular, criando-se um defeito em formato de caixa. Após 3 meses de regeneração, os retalhos foram elevados e posicionado um guia com uma lima endodôntica, com a finalidade de alinhar paralelamente à parede vestibular do defeito. O guia foi removido e, no lado direito inferior (grupo controle), foi obtido um enxerto ósseo do ramo ascendente da mandibula, que foi fixado a parede lateral do defeito por meio de parafusos. No lado esquerdo inferior (grupo teste), foi fixado um bloco de DBBM no defeito mandibular. Em ambos os lados, os blocos enxertados foram protegidos por uma membrana de colágeno reabsorvível. Em seguida os retalhos foram suturados. Após elevação do retalho, utilizou-se o guia para instalação de um implante de cada lado da mandíbula, entre o enxerto e o osso remanescente. Após 3 meses, os animais foram eutanasiados para obtenção das peças a serem processadas laboratorialmente para análise histológica. Resultados: Todos os implantes apresentaram-se clinicamente estáveis. A espessura da crista alveolar no grupo teste foi de 5.4, 9.4 e 9.3 mm, antes, imediatamente após a enxertia, e no momento da instalação dos implantes respectivamente. No grupo controle (enxerto ósseo autógeno), a espessura da crista alveolar foi de 5.2, 9.0 mm antes e imediatamente após o procedimento de enxertia (reconstrução). Após 3 meses... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Aim: - to evaluate the healing of the alveolar bony crest and the integration of implants installed in augmented sites with autologous bone or DBBM blocks, concomitantly with a collagen membrane. Material & methods: Mandibular molars were extracted bilaterally in 6 Labrador dogs, the buccal bony wall was removed and a box-shaped defect was created. After 3 months, flaps were elevated and a device was applied to a stent and used for the placement of an endodontic file that was lined up parallel to the buccal wall of the defect. The stent was removed and, in the right mandibular side, a bony graft was harvested from the ascending ramus and secured to the lateral wall of the defect by means of screws. In the left mandibular side, a DBBM block was fixed to the defect. A resorbable membrane was applied both sides. The flaps were sutured. After three months, one bone graft was exposed, and the dog was excluded from further analysis. After flap elevation, the stent and the device were used as guide to install one implant in each mandibular side, between the graft and the parent bone. After 3 months, biopsies were harvested and ground sections prepared for histological evaluation. Results: All implants were clinically stable. The width of the alveolar crest at the test sites was 5.4mm before, 9.4mm immediately after grafting, and 9.3mm at implant installation. At the control sites (autologous bone graft), the width of the alveolar crest was 5.2mm before and 9.0mm immediately after the grafting procedure. After 3 months of healing, the width was 8.7mm. One autologous bone block graft was lost before implant installation. All implants installed were available for histological evaluation (n=5). The autologous bone... (Complete abstract click electronic access below) / Doutor

Thesis in cotutelle with the University of Gothenburg, Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy Gothenburg, Sweden / Seeing is believing. Our understanding of phenomena often involves their direct observation. However, bone architecture is challenging to visualize given its multi-level hierarchical organization. In this thesis, bone and bone interfaces are characterized via multimodal and multiscale platforms, combining different techniques across several length scales. Imaging techniques across the micro-nano continuum are complemented by spectroscopy methods to explore, respectively, the structure and composition of bone and bone interfaces, using both light and electron probes. By applying a characterization methodology more typical of materials science, this thesis aims to unveil structural and compositional abnormalities of bone induced by disease [Papers I-II], and bone response to functionalized biomaterials in compromised conditions [Papers III-IV]. Additionally, it expands three-dimensional (3D) characterization opportunities at the nanoscale in both native and peri-implant bone [Papers V-VI]. This characterization approach uncovered changes in bone quality (structure and/or composition) in the compromised conditions under investigation in this thesis, i.e., leptin receptor (LepR) deficiency and medication-related osteonecrosis of the jaw (MRONJ) [Papers I-II]. In a preclinical model of LepR deficiency for type 2 diabetes/obesity, multimodal characterization of bone at the microscale showed structural abnormalities indicative of delayed skeletal development, despite unaffected bone matrix composition [Paper I]. A combination of multiscale imaging and spectroscopy techniques spanning the micro-to-nanoscale enabled a detailed study of the interface between necrotic bone and bacteria in a case of MRONJ, shedding light on possible mechanisms of bone degradation. When applied to bone-biomaterial interfaces, the application of a multimodal and multiscale characterization workflow informed perspectives on bone response to novel biomaterial solutions aimed to promote osseointegration in osteoporotic conditions via local drug delivery of phytoestrogens [Paper III] or anabolic agents [Paper IV]. This highlighted the importance of studying peri-implant bone at the mesoscale [Paper III] and of confirming biomaterial behaviour in vivo in the presence of surface functionalization [Paper IV]. Lastly, this thesis emphasized the importance of 3D imaging at the nanoscale with electron tomography to resolve bone ultrastructure at biomaterial interfaces [Paper V] and in native conditions [Paper VI]. Specifically, in Paper VI, artifact-free on-axis electron tomography resolved some long-debated aspects regarding the organization of mineralized collagen fibrils, the fundamental building block units of bone. / Thesis / Doctor of Philosophy (PhD) / Bone is a hierarchical material, meaning that smaller components are progressively organized into larger structures. This multi-level architecture is hard to visualize because different techniques are required to obtain information at different length scales. However, as the proverb says, “seeing is believing”, and our understanding of things is often better accomplished by looking at images. This thesis applies a characterization approach more typical of materials science to study the structure, composition, and repair of bone across multiple length scales. This characterization approach is multimodal because it uses different techniques, and multiscale because it targets different length scales in bone. In particular, this thesis focuses on bone in compromised conditions, namely osteoporosis, diabetes, and medication-related osteonecrosis, to understand the impact of disease-induced changes in bone properties. It also examines how bone organizes itself at a fundamental level, which is a critical aspect to understand since bone is built from the bottom-up.

Thesis (M.S.)--University of Michigan, 2004. / Includes bibliographical references.

Thesis (M.S.)--University of Michigan, 2001. / Includes bibliographical references.