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1
Kanter, Britta. "Osseointegration kalthaertender Knochenzemente im Schafmodell." Diss., Ludwig-Maximilians-Universität München, 2014. http://nbn-resolving.de/urn:nbn:de:bvb:19-174590.
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Da es bisher noch kein Knochenersatzmaterial gibt, das den komplexen Eigenschaften des Knochengewebes entspricht, wird intensiv an der Entwicklung neuer Materialien geforscht. In der vorgestellten Studie wurden ein Calciumphosphat- und ein Magnesiumphosphat-Zement (Bruschit bzw. Struvit) in einem unbelasteten und einem teilbelasteten Knochendefekt kritischer Größe im Schafmodell untersucht. Von jeder Zementformulierung kamen zwei unterschiedliche Pulver-Flüssigkeits-Verhältnisse (2,0 und 3,0), welche zu unterschiedlichen Porositäten der abgebundenen Zemente führten, zum Einsatz. Die Implantationszeiträume betrugen 4, 7 und 10 Monate. Als Kontrolle diente bei der 10-Monats-Gruppe ein CDHA-Zement (Ca9(PO4)5HPO4OH) bzw. ein Leerdefekt.
Alle Zementformulierungen erwiesen sich als biokompatibel und osteokonduktiv. Bei den Struvit-Zementen (MgNH4PO4•6H2O) konnte nach 10 Monaten Implantation eine fast komplette Degradation beobachtet werden. Diese fand sowohl passiv durch chemisch-physikalische Lösungsvorgänge als auch aktiv, d.h. zellvermittelt, statt. Gleichzeitig bildete sich neues trabekuläres Knochengewebe, so dass gesagt werden kann, dass die Resorptions-geschwindigkeit der Geschwindigkeit der Knochenformation entsprach. Die mechanische Stabilität nahm zwar gegenüber den in vitro ermittelten Werten nach Implantation stark ab, wurde aber im Zeitverlauf durch das Einwachsen von neuem Knochengewebe wieder auf ein physiologisches Niveau angehoben. Signifikante Unterschiede zwischen den Porositäten gab es nur zum Teil hinsichtlich des verbliebenen Zementvolumens. Aufgrund der besseren Verarbeitbarkeit als injizierbare Paste, wäre ein Pulver-Flüssigkeits-Verhältnis von 2,0 eventuell besser für den klinischen Einsatz geeignet als ein Pulver-Flüssigkeits-Verhältnis von 3,0. In Kontakt mit Weichgewebe lösten sich die Struvit-Zemente schneller auf als neues Knochengewebe einwachsen konnte. Durch weitere Modifikationen bei der Zementzusammensetzung könnte dies verhindert werden. Durch die Kombination mit einem im Verhältnis zu Struvit stabileren Calciumphosphat (z.B. β-Tricalciumphosphat) könnte ein biphasischer Zement entwickelt werden, bei dem sich die einzelnen Komponenten unterschiedlich schnell auflösen.
Die Bruschit-Zemente (CaHPO4•2H2O) und der CDHA-Zement zeigten selbst nach zehn Monaten Implantation kaum Degradation. Bei dem CDHA-Zement war dies zu erwarten, bei den Bruschit-Zementen jedoch nicht. Die Ursache hierfür kann bei der höheren Porosität (PLR 2,0) in der Phasenumwandlung von Bruschit zu Octacalciumphosphat bzw. generell in der Zementkomposition gesehen werden. Da die Bruschit-Zemente im teilbelasteten Defekt Risse aufwiesen, war ihre mechanische Stabilität in vivo für lasttragende Bereiche nicht ausreichend. Deshalb wäre es nötig, die Bruschit-Zemente weiter zu modifizieren, bevor sie erneut im Tiermodell untersucht werden können. Um die Stabilität zu verbessern, könnten Keramik- oder Polymerfasern in den Zement eingebracht werden. Für die Verbesserung der Degradation sollte eine andere Flüssigkeitskomponente, z. B. Natriumhyaluronat oder Pyrophosphat, wie sie in anderen Studien verwendet wurden, in Betracht gezogen werden.
Zusätzlich zu den orthotopen Implantaten wurden jeweils auch subkutan Formkörper eingebracht. Diese zeigten, dass die untersuchten Zemente auch eine gewisse Osseoinduktivität besaßen. Im Fall der Bruschit-Zemente verhielten sich die subkutanen Implantate allerdings anders als die im Knochen implantierten Zemente. Im Gegensatz zu den orthotopen Implantaten zeigten die Formkörper im subkutanen Gewebe eingesetzt eine deutliche Größenreduktion. Die Ursache dafür kann im unterschiedlichen Gewebemilieu oder in der unterschiedlichen Implantatform (orthotop: Paste / heterotop: Block) gesehen werden. Um eine möglichst genaue Aussage über das biologische Verhalten eines Materials treffen zu können, ist es daher notwendig, die Materialien immer in der Form und im entsprechenden Zielgewebe zu untersuchen, wie sie später verwendet werden sollen, d.h. ein Zement als resorbierbares Knochenersatzmaterial sollte immer als Paste im Knochenlager untersucht werden. Auch eine Untersuchung in einem belasteten Implantationsmodell ist sinnvoll, da eine mechanische Belastung einen Einfluss auf das Verhalten der Zemente und das Knochenremodelling hat.Osseointegration of cold-setting bone-cements in an ovine model The perfect bone substitute material which matches the properties of bone has still not been found. Therefore, intensive research is on-going. In the present study a calciumphosphate- and a magnesiumphosphate-cement (brushite and struvite respectively) were investigated. The cements were implanted in sheep using a partially loaded and an unloaded critical size bone defect. Each formulation was tested in two different powder-to-liquid-ratios (PLR 2.0 and 3.0), resulting in different porosities of the hardened cements. The implantation periods were 4, 7 and 10 months. For the 10 months’ group there were two controls: a CDHA cement (Ca9(PO4)5HPO4OH) and an unfilled defect. Every investigated cement formulation proved to be biocompatible and osteoconductive. After ten months of implantation in live sheep, the struvite cements (MgNH4PO4•6H2O) showed a nearly complete degradation which was closely followed by new trabecular bone formation. The degradation observed was both passive to chemical dissolution and active to cellular activity. The mechanical properties of the struvite-cements decreased extensively, up to 90 %, after implantation. However, over the ten months of this study, the stiffness level caused by the infilling bone reached normal physiological ranges. There were no significant differences between the porosities except in the area of residual cement in some cases. Nevertheless, for clinical use, a PLR of 2.0 would be preferable to a PLR of 3.0 because an injectable cement provides better handling. When the struvite cement is in contact with soft tissue, it dissolves too quickly for proper bone ingrowth. Therefore, further modifications to the cement formulation are required. For example, a biphasic cement could be developed in which the individual components dissolve at different rates. This could be achieved through the combination of struvite and a more stable calcium phosphate (eg, β-tricalcium phosphate). The brushite cements (CaHPO4•2H2O), as well as the CDHA cement, showed barely any resorption even after ten months of implantation. For the CDHA cement this was expected, but not for the brushite cements. These findings could be due to changes in the phase composition which occured in the brushite cements with a PLR of 2.0, rather than due to the cement formulation itself. The partially-loaded defect model revealed that the brushite cements were not suitable for load-bearing applications because cracks formed in the cement. Hence, it is recommended that the cement formulations be modified before they are investigated again. To enhance the stability, ceramic or polymer fibers might prove successful when incorporated into the cement. To improve degradation behavior, another liquid component such as sodiumhyaluronat or pyrophosphate, as used in other studies, should be considered. In addition to the bone implants, moulds of each cement formulation were implanted subcutaneousely. Bone formation at these implants exhibited certain osteoinductive properties of the cements. By the time of implantation, the subcutaneous brushite implants had reduced in volume in contrast to the bone implants. The cause may be found in the different tissue milieu or in the different implant type (orthotopic: paste / heterotopic: block). When researching the specific biological behaviours of a biomaterial, it is necessary to examine the materials using them with the same type and corresponding target tissue as it will be used in clinical use. In such cases, cements used as resorbable bone substitute materials should always be investigated as a paste and in a suitable bone defect. Also, a study in a loaded implant model is useful, since a mechanical load has an influence on the behavior of the cements and the bone remodelling.
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Herbert, Amy Angharad. "Bone grafting : tissue treatment and osseointegration." Thesis, Cardiff University, 2004. http://orca.cf.ac.uk/55547/.
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Bone grafts fill skeletal defects and provide a structure upon which new bone can be deposited. There is no standard method of storing bone prior to grafting, the three main storage regimes being stored fresh frozen at -80°C, gamma irradiated or freeze dried. The initial aim of this project was to determine how osteoblastic cells behaved when exposed to bone treated in the above ways. It was found that sterilisation of bone with gamma irradiation caused cell death in a number of the cells that came into contact with it. Therefore the use of gamma irradiation for grafting is contraindicated, a similar observation was observed for freeze-dried bone whereas cells grew and differentiated on fresh frozen tissue. The second aim of this study was to develop a system whereby bone marrow cells could be expanded in culture and retain their osteogenic potential so that they would be suitable for either coating a bone graft (thus increasing the rate of osseointegration of the graft) or used alone to treat small bone defects. Rodent bone marrow was used in a variety of cultures and bone formation was induced by either BGJ-b medium or ECCM (Endothelial cell conditioned medium). Control cultures were grown in alpha modification minimum essential medium. ECCM was overall found to produce a greater number of cells at the end of the incubation periods studied than BGJ-b medium. BGJ-b medium preferentially selected mineralization over cell proliferation under all of the culture conditions studied (monolayers, collagen gels and organ cultures). This medium would be best suited to forming small pieces of bone rapidly from bone marrow, to fill small bone defects such as those seen in the dental field. ECCM produced large numbers of osteogenic cells, which could potentially be used to coat large bone grafts.
3
Thomson, Seamus David. "Clinical and Laboratory Studies in Osseointegration." Thesis, The University of Sydney, 2019. http://hdl.handle.net/2123/20130.
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Osseointegration for lower limb amputees entails the anchorage of a percutaneous implant into the residual bone, where a prosthesis may be attached externally. The development of this technology was to overcome the shortcomings of conventional prostheses options for amputees including poor mobility outcomes, limited prosthesis use, and induction or amplification of major diseases. Little is known about the long-term success of Osseointegration, and there are gaps in the available literature of its physiological periprosthetic status for recipients. This body of work evaluates periprosthetic bone remodelling around two different types of osseointegrated prostheses, and bone remodelling in regions proximal to these types of implants. A new plasma-printing device designed for space technologies was appropriated to deposit biomaterials for implant surface coating purposes with material characterisation. Lastly, technology cross-over between space instrumentation and Osseointegration was evaluated in the context of the current problems faced by osseointegrated implant recipients and future implant designs. This dissertation outlines milestone clinical and laboratory findings in Osseointegration that will hopefully translate into new implant designs in context of the bone physiology results observed, and applications of new technologies. Overall, the future of Osseointegration appears promising and is likely to remain an impactful area of research for solving the issues associated with amputees.
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Pitchai, Manju Sofia. "Harnessing the immune response to enhance osseointegration." Thesis, Griffith University, 2022. http://hdl.handle.net/10072/418638.
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New understanding of immune system biology has led a paradigm shift in the development of biomaterials away from classically ‘inert’, to ‘immuno-modulatory’ biomaterials that have the potential to stimulate an immune response able to promote constructive and functional tissue remodeling responses as opposed to persistent inflammation and scar tissue formation. This project aims to examine macrophage behavior and in particular integrin expression at the cell–biomaterial interface in vitro, in order to delineate the underlying molecular events occurring during biomaterial-mediated osseous healing. After reviewing the current literature to identify research gaps that this thesis should focus on, the activation of macrophages with controlled timing, and modulation of their interactions with other cell types involved in wound healing, emerged as key strategies to improve biomaterial efficacy. Careful design of biomaterial structure and controlled release of immunomodulators can be employed to manipulate macrophage phenotype for the maximization of the wound healing response with enhanced tissue integration and repair, however, to elicit predictable immune responses there is a need for a thorough understanding of how the biomaterial properties can be tuned to harness a designed immunological outcome.
Our systematic review of in vitro studies suggested that the initial immune response of macrophages to titanium may be modulated by its surface characteristics both topographically and physiochemically. We therefore assessed the potential effects of three novel titanium surfaces; Machined, Blasted and Fluoride-treated, on macrophage phenotype. We chose a monocytic cell-line as our macrophage source rather than using primary macrophages, as the inflammatory status of primary cells could not be readily defined nor reproduced between experiments. This was crucial to the overall study if we were to clearly assess any changes in macrophage phenotype as a result of their II interaction with the titanium surfaces. We subsequently analysed in some detail the experimental processes involved in the optimization of macrophage cell culture, macrophage differentiation and phenotype characterization.
We used microscopy, profilometry and elemental analysis to understand how the roughness of the titanium surfaces affected macrophage viability and proliferation in both non-activated ‘M0’ and activated inflammatory ‘M1’ macrophages. Subsequent analysis of one of the key mediators of cell attachment to biomaterials showed for the first time that αM, β1, β2 and α2 integrins play an important role in the adhesion of non-polarised M0 macrophages onto both smooth and rough titanium surfaces. Moreover, the distinct temporal expression profile of αM integrin expression correlated broadly with the subsequent secretion profiles of inflammatory cytokines IL-1β and TNF-α in these cells. Specific integrin expression also played an important role in the adhesion of polarised inflammatory M1 macrophages onto surface-modified titanium surfaces. In these cells, early integrin αM and β1 in particular, along with integrin α2 was associated with modulation of the subsequent cytokine response in these cells. Furthermore, the surface induced differential expression of integrins on the different titanium surfaces showed the Fluoride-modified surface in general induced greater cytokine and integrin modulation than either the Machined or Blasted surfaces. While now biologically plausible, further studies to fully determine how integrin-derived modulation of the macrophage-associated inflammatory response following macrophage attachment as suggested by these studies, can enhance wound healing and osteogenesis are required. Despite this, ‘harnessing the immune response’ is clearly a potential goal of engineered titanium implant surfaces in order ‘to enhance osseointegration’.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Medicine & Dentistry
Griffith Health
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Silva, Manuel A. B. da. "Osseointegration bei dentalen Implantaten eine Literaturübersicht und -auswertung /." [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=969451679.
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Bernhardt, Ricardo. "Dreidimensionale Charakterisierung der Osseointegration von Titanimplantaten mittels Mikrocomputertomographie." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2007. http://nbn-resolving.de/urn:nbn:de:swb:14-1169046173395-60123.
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Die Entwicklung und Erprobung von metallischen Implantatwerkstoffen mit biologischen Beschichtungen für den Einsatz im menschlichen Knochen verlangt, neben der Untersuchung grundlegender zellbiologischer Wechselwirkungen, eine ganzheitliche Betrachtung ihrer Wirkungsweise im lebenden Organismus. Die vorwiegend angewandte Methode zur Quantifizierung des Potentials von Biofunktionalisierungen metallischer Implantate ist dabei die histologische Auswertung. Diese stützt sich aber auf Informationen aus nur wenigen und eher zufälligen Schnittlagen im Probenvolumen, was mit einer hohen Anzahl an Tierexperimenten ausgeglichen wird. Mit der Mikrocomputertomographie steht neben der klassischen Histologie eine zerstörungsfreie Methode zur Verfügung, welche eine detaillierte dreidimensionale Darstellung des neugebildeten Knochengewebes ermöglicht. Die Abbildungsqualität des mineralischen Knochengewebes um Titanimplantate, als Grundlage für eine Vergleichbarkeit von Tomographie und Histologie, wurde anhand von drei Mikrofokus-Computertomographen und einem Synchrotron-Computertomographen am HASYLAB untersucht. Die tomographische Untersuchung von Hartgewebe einschließlich metallischer Implantate zeigte mit Hilfe von Synchrotronstrahlung die beste qualitative Übereinstimmung zur histologischen Bildgebung. Für die Quantifizierung der Knochenneubildung wurden interaktive Analysemodelle erarbeitet, welche eine vereinheitlichte Auswertung von histologischen und tomographischen Informationen erlaubt. Auf Grundlage der entwickelten Analyseprozeduren war es erstmals möglich, die statistische Belastbarkeit der Ergebnisse aus der histologischen und tomographischen Analyse zu untersuchen. Dabei konnte gezeigt werden, dass hinsichtlich der Herausstellung von Unterschieden bei der Osseointegration modifizierter Titanimplantate mit beiden Methoden ähnliche Ergebnistrends gefunden werden. Eine Signifikanz (p < 0,01) der Unterschiede bei der Knochenneubildung konnte jedoch ausschließlich mit der mikrotomographischen Analyse herausgestellt werden. Die Ergebnisse bei der Darstellung und Analyse des mineralischen Gewebes durch die Nutzung der Synchrotrontomographie gehen weit über die Grenzen der histologischen Untersuchungen hinaus. Durch den dreidimensionalen Charakter der Informationen ergeben sich dabei neue Bewertungsmodelle zur Beurteilung der Osseointegration von biofunktionalisierten Implantaten. Die mikrotomographische Analyse führt gegenüber der histologischen Auswertung durch die geringe Irrtumswahrscheinlichkeit der Ergebnisse bei deutlich verminderter Probenanzahl zu einer erheblichen Verringerung von Tierversuchen.
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Sjostrom, Terje. "Nanopatterning of titanium surfaces for improved implant osseointegration." Thesis, University of Bristol, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.503860.
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With increasingly higher performance requirements and health care costs associated with dental and orthopaedic bone-anchored implants there is a need to improve the osseointegration of Ti implants. Small alterations in nanotopography feature dimensions and arrangement has recently been shown able to differentiate human mesenchymal stem cells into an osteoblastic lineage, thus showing potential for using nanotopography to improve osseointegration of Ti implants.
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Shao, Fei. "Natural frequency analysis for osseointegration trans-femoral implant." Thesis, University of Surrey, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.443397.
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Bernhardt, Ricardo. "Dreidimensionale Charakterisierung der Osseointegration von Titanimplantaten mittels Mikrocomputertomographie." Doctoral thesis, Technische Universität Dresden, 2006. https://tud.qucosa.de/id/qucosa%3A23934.
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Die Entwicklung und Erprobung von metallischen Implantatwerkstoffen mit biologischen Beschichtungen für den Einsatz im menschlichen Knochen verlangt, neben der Untersuchung grundlegender zellbiologischer Wechselwirkungen, eine ganzheitliche Betrachtung ihrer Wirkungsweise im lebenden Organismus. Die vorwiegend angewandte Methode zur Quantifizierung des Potentials von Biofunktionalisierungen metallischer Implantate ist dabei die histologische Auswertung. Diese stützt sich aber auf Informationen aus nur wenigen und eher zufälligen Schnittlagen im Probenvolumen, was mit einer hohen Anzahl an Tierexperimenten ausgeglichen wird. Mit der Mikrocomputertomographie steht neben der klassischen Histologie eine zerstörungsfreie Methode zur Verfügung, welche eine detaillierte dreidimensionale Darstellung des neugebildeten Knochengewebes ermöglicht. Die Abbildungsqualität des mineralischen Knochengewebes um Titanimplantate, als Grundlage für eine Vergleichbarkeit von Tomographie und Histologie, wurde anhand von drei Mikrofokus-Computertomographen und einem Synchrotron-Computertomographen am HASYLAB untersucht. Die tomographische Untersuchung von Hartgewebe einschließlich metallischer Implantate zeigte mit Hilfe von Synchrotronstrahlung die beste qualitative Übereinstimmung zur histologischen Bildgebung. Für die Quantifizierung der Knochenneubildung wurden interaktive Analysemodelle erarbeitet, welche eine vereinheitlichte Auswertung von histologischen und tomographischen Informationen erlaubt. Auf Grundlage der entwickelten Analyseprozeduren war es erstmals möglich, die statistische Belastbarkeit der Ergebnisse aus der histologischen und tomographischen Analyse zu untersuchen. Dabei konnte gezeigt werden, dass hinsichtlich der Herausstellung von Unterschieden bei der Osseointegration modifizierter Titanimplantate mit beiden Methoden ähnliche Ergebnistrends gefunden werden. Eine Signifikanz (p < 0,01) der Unterschiede bei der Knochenneubildung konnte jedoch ausschließlich mit der mikrotomographischen Analyse herausgestellt werden. Die Ergebnisse bei der Darstellung und Analyse des mineralischen Gewebes durch die Nutzung der Synchrotrontomographie gehen weit über die Grenzen der histologischen Untersuchungen hinaus. Durch den dreidimensionalen Charakter der Informationen ergeben sich dabei neue Bewertungsmodelle zur Beurteilung der Osseointegration von biofunktionalisierten Implantaten. Die mikrotomographische Analyse führt gegenüber der histologischen Auswertung durch die geringe Irrtumswahrscheinlichkeit der Ergebnisse bei deutlich verminderter Probenanzahl zu einer erheblichen Verringerung von Tierversuchen.
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Bonsignore, Lindsay Ann. "SURFACE CONTAMINANTS INHIBIT THE OSSEOINTEGRATION OF ORTHOPAEDIC IMPLANTS." Case Western Reserve University School of Graduate Studies / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=case1341323221.
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Hyzy, Sharon Leigh. "Adverse effects of bone morphogenic protein-2 during osseointegration." Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/44728.
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Modifications of biomaterial surface properties are employed to increase osteoblast differentiation and bone formation. Microtextured metallic surfaces promote osteoblast differentiation and high surface energy- achieved by controlling surface hydrocarbon contamination- increases osteoblast differentiation and peri-implant bone formation. Recombinant human bone morphogenic protein 2 (BMP2) is approved to induce bone formation in a number of applications. It is used clinically in combination with biomaterials to improve peri-implant bone formation and osseointegration. The amount of BMP2 that is required is large and inflammatory (swelling/seroma) and bone-related (ectopic bone/bone resorption) complications have been reported after BMP2 treatment. The aim of this study was to examine potential deleterious effects of BMP2 on the inflammatory environment and apoptosis of osteoblasts.
Surface roughness and energy decreased pro-inflammatory interleukins and increased anti-inflammatory interleukins. In contrast, BMP2 abolished the surface effect, increasing pro-inflammatory interleukin (IL) 6, IL8, and IL17 in a surface roughness-dependent fashion and decreasing anti-inflammatory IL10 on rough surfaces. 5Z-7-Oxozeaenol and Dorsomorphin, but not H-8, blocked the effect of BMP2 on IL1A expression. There was an increase in expression of IL6 when treated with BMP2 for the control and H-8 groups, but both 5Z-7-Oxozeaenol and Dorsomorphin blocked the effect. Both 5Z-7-Oxozeaenol and H-8 blocked the effect of BMP2 on IL10 expression.
BMP2 treatment had little effect on apoptosis in human mesenchymal stem cells (MSCs). Exogenous BMP2 had no effect on TUNEL. Caspase-3 activity was increased only at 200ng/ml BMP2. BAX/BCL2 decreased in MSCs treated with 50 and 100ng/ml BMP2. In contrast, BMP2 increased caspase-3 activity and TUNEL at all doses in normal human osteoblasts (NHOst). BAX/BCL2 increased in NHOst treated with BMP2 in a dose-dependent manner. Cells treated with 200 ng/ml BMP2 had an 8-fold increase in BAX/BCL2 expression in comparison with untreated cells. Similarly, BMP2 increased DNA fragmentation in NHOst cells. The BMP2-induced increase in DNA fragmentation was eliminated by 5-Z7-Oxozeaenol and Dorsomorphin.
The results suggest that while surface features modulate an initial controlled inflammatory response, the addition of BMP2 induces a pro-inflammatory response. The effect of BMP2 on apoptosis depends on cell maturation state, inducing apoptosis in committed osteoblasts. BMP2 together with microtextured orthopaedic and dental implants may increase inflammation and possibly delay bone formation. Dose, location, and delivery strategies are important considerations in BMP2 as a therapeutic and must be optimized to minimize complications.
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Jalota, Sahil. "Development and in vitro examination of materials for osseointegration." Connect to this title online, 2007. http://etd.lib.clemson.edu/documents/1181668741/.
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Konan, S. "Augmenting osseointegration of implants using bone marrow stromal cells." Thesis, University College London (University of London), 2013. http://discovery.ucl.ac.uk/1382600/.
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Introduction: The greatest challenge facing the success of orthopaedic implants is improving their fixation to bone to enhance their longevity. Bone marrow stromal cells (BMSC), are a population of plastic-adherent cells derived from the bone marrow. The main hypothesis of this thesis is that viable BMSC can be applied to implants using a fibrin glue-spray system; and increase bone formation adjacent to the implants and improve bone-implant contact. Methods: The experiments were undertaken in a large animal model. Four scenarios were tested 1) The ability of BMSC to improve implant fixation using models of total hip replacement, massive endoprosthetic replacement and bone defect around pins. 2) The effect of varying cell dosages of BMSC in their ability to produce new bone and improve bone implant contact. 3) The effect of differentiating the BMSC along the osteogenic pathway in their ability to produce new bone and improve bone implant contact. 4) The effect of using semi-permeable barriers around BMSC sprayed on implants to prevent cell migration Results: 1) BMSC sprayed on the surface of implants resulted in increased bone formation in the total hip replacement, massive endoprosthetic replacement and bone defect around pin models. 2) Bone formation was higher with osteogenic 10x106 BMSC (112.67 ± 30.75 mm2) compared to osteogenic 2x106 BMSC (76.84 ± 2.25 mm2). No significant difference was noted in bone formation between undifferentiated 1x105 BMSC (30.76 ± 9.43%) and undifferentiated 10x106 BMSC (28.27 ± 14.64%). 3) Osteogenic differentiated 10x106 BMSC (112.67 ± 30.75 mm2) produced more bone than undifferentiated 10x106 BMSC (58.22 ± 17.22 mm2). 4) Using semipermeable barriers resulted in significantly increased bone formation when undifferentiated 1x105 BMSC (61.32 ± 6.94% vs 30.76 ± 9.43%) or undifferentiated 10x106 BMSC (57.46 ± 4.39% vs 28.27 ± 14.64%) was used. This difference was not noted when osteogenic differentiated 10x106 BMSC was used. The experiments confirm that viable BMSC can be successfully isolated from bone marrow aspiration, differentiated along the osteogenic pathway and sprayed on the surface of various orthopaedic implants to improve bone-implant contact. Conclusion: This technique of using BMSC may be an ideal alternative to improve osseointegration of implants in challenging clinical scenarios with deficient bone stock.
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Reinhardt, Carina. "Investigations of the bone titanium interface, in vitro." Thesis, University of Surrey, 2003. http://epubs.surrey.ac.uk/844654/.
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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.
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Allmendinger, Jörg. "Mikroradiografische Untersuchung zur Osseointegration von laserstrukturierten Titanimplantaten im intramedullären Kaninchenmodell." kostenfrei, 2009. http://d-nb.info/999529951/34.
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Reyes, Catherine Diane. "Collagen- and Fibronectin-Mimetic Integrin-Specific Surfaces That Promote Osseointegration." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/11599.
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Cell adhesion to the extracellular matrix through cell-surface integrin receptors is essential to development, wound healing, and tissue remodeling and therefore represents a central theme in the design of bioactive surfaces that successfully interface with the body. This is especially significant in the areas of integrative implant coatings since adhesion triggers signals that regulate cell cycle progression and differentiation in multiple cellular systems. The interactions of osteoblasts with their surrounding extracellular matrix are essential for skeletal development and homeostasis and the maintenance of the mature osteoblastic phenotype. Our objective was to engineer integrin-specific bioactive surfaces that support osteoblastic differentiation and promote osseointegration by mimicking these interactions. We target two specific integrins essential to osteoblast differentiation the type I collagen receptor alpha2beta1 and the fibronectin receptor alpha5beta1. The central hypothesis of this project was that the controlled presentation of type I collagen and fibronectin binding domains onto well-defined substrates would result in integrin-specific bioadhesive surfaces that support osteoblastic differentiation, matrix mineralization, and osseointegration. We have demonstrated that these biomimetic peptides enhance bone formation and mechanical osseointegration on titanium implants in a rat tibia cortical bone model. We have also shown that the presentation of multiple integrin-binding ligands synergize to enhance intracellular signaling and proliferation. Finally, we demonstrate the advantage of the short biomimetic peptides over the native ECM proteins. This research is significant because it addresses current orthopaedic implant limitations by specifically targeting cellular responses that are critical to osteoblastic differentiation and bone formation. This biomolecular approach provides a versatile and robust strategy for developing bioactive surfaces that enhance bone repair and osseointegration of orthopaedic implants.
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Kanter, Britta [Verfasser], and Eckard [Akademischer Betreuer] Wolf. "Osseointegration kalthärtender Knochenzemente im Schafmodell / Britta Kanter. Betreuer: Eckard Wolf." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2014. http://d-nb.info/1060006502/34.
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Du, Zhibin. "The effects of osteoporosis on osseointegration in the rat maxilla." Thesis, Queensland University of Technology, 2015. https://eprints.qut.edu.au/87977/1/Zhibin_Du_Thesis.pdf.
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The study investigated the effects of oestrogen deficiency on dental implant in a rat model. An osteoporosis rat model was successfully established for dental implant research and it was noted that bone cells functioned differently in osteoporotic condition during the healing of dental implant. The study further demonstrated that implant surface roughness could stimulate bone formation, therefore, improve the bone healing in osteoporotic condition.
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Li, Junyuan, and 黎俊媛. "Effects of surface-modified titanium implants on osseointegration in irradiated bone." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/206341.
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da, Silva Barros Sara Maria. "Development of hybrid coatings for osseointegration improvement of metal dental implants." Doctoral thesis, Universitat Jaume I, 2016. http://hdl.handle.net/10803/398841.
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Los implantes de titanio presentan comprobada biocompatibilidad no obstante carecen de propiedades osteoinductoras. Las estrategias actuales de modificación superficial de los implantes no resultan plenamente efectivas en casos particulares de baja calidad del hueso receptor. La presente tesis doctoral plantea una nueva estrategia basada en recubrimientos superficiales bioabsorbibles de base silicio para mejorar el éxito de dichos implantes. Para alcanzar dicho objetivo se han sintetizado vía sol-gel diversos recubrimientos a partir de los precursores de silicio trimetoximetilsilano (MTMOS), 3-glicidoxipropiltrimetoxisilano (GPTMS) y tetraetoxisilano (TEOS). Se ha realizado una detallada caracterización de los recubrimientos, especialmente en lo que a sus propiedades físicas, químicas y biológicas se refiere. Los resultados obtenidos muestran que todos los recubrimientos se encuentran bien adheridos a la superfície metálica, además, el prototipo final ha demostrado ser claramente biocompatible con los tejidos vivos sin mermar las propiedades osteoconductivas de los implantes de titanio comerciales.Titanium dental implants have proved biocompatibility, nevertheless, they lack of osteoinductive properties. The usual strategy of modifying titanium dental implants' surfaces is not fully effective in the special situations of poor bone quality. THis work focuses on a new strategy that consists on developing synthetic and biologically absorbable silica-based external coatings to improve these implants' success. In order to achieve this purpose, sol-gel technology was used to synthesize several coatings based on the precursors trimethoxymethylsilane (MTMOS), 3-glycidyloxypropylsilane (GPTMS) and tetraethoxysilane (TEOS). The coatings were thoroughly characterized, specifically focusing on their physical and chemical properties as well as on their biological performance. Resukts show taht all the synthesized coatings were well adhered to the metal surface and the final prototype shows clear biocompatibility with living tissues without affecting the osteoconductive properties of the commercial titanium dental implants.
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Keller, Tanja. "Osseointegration einer mit Plasma-Immersions-Ionen-Implantation behandelten Autokompressionsklammer aus Nitinol." Diss., lmu, 2004. http://nbn-resolving.de/urn:nbn:de:bvb:19-20903.
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Grandfield, Kathryn. "Nanoscale Osseointegration : Characterization of Biomaterials and their Interfaces with Electron Tomography." Doctoral thesis, Uppsala universitet, Tillämpad materialvetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-179445.
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Bone response is one of the key determining factors in the overall success of biomaterials intended for bone regeneration and osseointegration. Understanding the formation of bone at an implant surface may lead to the improved design of biomaterials for the future. However, due to the inhomogeneity of bone tissue at an interface, two-dimensional images often lack detail on the interfacial complexity. Furthermore, the increasing use of nanotechnology in the design and production of biomaterials demands characterization techniques on a similar nano length scale. While current analysis methods, such as X-ray tomography, transmission electron microscopy, focused ion beam microscopy and scanning electron microscopy, provide a basis for analysing biomaterials and biointerfaces, they are incapable of doing so with both nanometre resolution and three-dimensional clarity. In contrast, electron tomography may be used to characterize the three-dimensional structure of biomaterials and their interfaces to bone with nanometre resolution. In this work, hydroxyapatite scaffolds, and laser-modified titanium and Ti6Al4V implants were studied in contact with human or rabbit bone. Z-contrast electron tomography revealed that the orientation of collagen in bone apposing hydroxyapatite, titanium and Ti6Al4V implants is consistently parallel to the implant surface, where the bioactive layer that precipitates on HA is oriented perpendicular to the implant surface. With this method, complete three-dimensional nanoscale osseointegration of titanium-based implants was also established. The extension of this technique from interfacial analyses to the design of biomaterials provided an understanding of the pore structure of mesoporous titania. In further investigations, the open three-dimensional pore network, as revealed by electron tomography, showed promise as a coating that improves implant osseointegration and enables site-specific drug-delivery from an implant surface. In summary, it was demonstrated that two-dimensional characterization techniques were insufficient for the investigation of nanostructured biomaterials, as well as their interfaces to bone. Visualizing biointerfaces and biomaterials with nanometre precision in three-dimensions can expose new fundamental information on materials properties and bone response, enabling better design of biomaterials for the future.
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Clokie, Cameron M. L. (Cameron Malcolm Lang). "The titanium-bone interface : a clinical and morphological analysis of osseointegration." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39399.
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Clinical and morphological investigations were carried out concerning the osseointegration of dental implants. A clinical evaluation of 1087 implants placed over a seven year time span revealed an osseointegration success rate of 96%. Studies indicated that, on average 8.7 months lapsed between implant insertion and prosthesis delivery. A technique was developed to evaluate the process of osseointegration with the light microscope (LM) and transmission electron microscope (TEM). A rat model was used and threaded implants were fabricated from solid commercially pure titanium. LM demonstrated osseointegration and a preservation of implant surface topography utilizing this technique. TEM analysis revealed an electron dense lamina-limitans like layer covered by an amorphous substance adjacent to the surface of the implant. $ sp3$H-proline was used to label seams of bone formation in order to evaluate the distribution and rate of formation of the new bone next to the metal implant. Bone appeared to grow from the old presurgical bone towards the implant with no apparent direct influence of the metal. A quail embryo model was developed to evaluate the effects of vascular occlusion on the formation of bone and to label epithelial blood vessels with iodinated transforming growth factor-beta 1 applied to the chorioallantoic membrane. These preliminary experiments demonstrated that surgical manipulation of the quail embryo was possible for the purposes of studying the process of osseointegration.
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Omoniala, Kennedy. "Surface modification strategies for antimicrobial titanium implant materials with enhanced osseointegration." Thesis, De Montfort University, 2016. http://hdl.handle.net/2086/14462.
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The use of exogenous materials to replace or repair dysfunctional tissues and organs has seen dramatic improvements since the time of the ‘physician-hero’. The past three decades have heralded the advancement of various materials and technologies for medical implant devices to repair, replace or regenerate irreversibly damaged tissues. Improvement in health outcomes, evident in life expectancy increase, has brought in its wake the increased need to replace or repair tissues, particularly weight-bearing bone tissues. Titanium (Ti), a non-magnetic, corrosion resistant, osseo-integrating metal, with a higher strength-to-weight ratio than the traditional stainless steel, has emerged as the material of choice for replacing bone and other support tissues. However, the quest for improved performance (osseointegration) and reduction in implant related infection resulting in the need for resection surgeries, has necessitated the need to improve the titanium-tissue interface mediated osseointegration process, and confer antimicrobial properties to the implant material surface. In this work, a simple cost effective physical and chemical modification strategies have been developed, to alter the surface chemistry, increase the surface water wettability and confer a nano topographic characteristic to the Ti surface. These surface parameters have been demonstrated to enhance the osseointegration process. The chemical treatments resulted in oxides containing the following ions: Calcium (Ca), for improvement of osteogenic cell adhesion to Ti surface, Silver (Ag), and Zinc (Zn) for conferring antimicrobial properties to the novel surface, and their composites (CaAg, CaZn and CaZnAg), Scanning electron microscope (SEM) profiles of the modified surface suggest that, ions are chemically bound and not physically deposited onto the Ti surface. Further evidence of this is provided by the release profile of these elements from the modified surface over a 28-day period. We have also demonstrated that, the physically modified Ti surface is better at incorporating our elements of interest than the commercially pure titanium (cpTi) surface. xi The results from a Staphylococcus aureus biofilm formation assay, and U2OS bone cell adhesion and proliferation studies, suggest that, the physical modifications enhanced both the antimicrobial performance and the osteoblast-like cell adhesion and proliferation. The suggestion also is that, the incorporated Ca further enhances the adhesion and proliferation of bone-like cells, whereas Zn and markedly Ag improve the modified Ti surface’s antimicrobial properties. However, Ag alone has been shown to have a toxic effect on the bone cells; a promising combination treatment involving Ca, Zn and Ag appears to have beneficial response in all tests.
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Röhling, Stefan. "Osseointegration von Zirkoniumdioxidimplantaten mit mikrorauer Oberflächentopografie im Vergleich zu Titan-SLA Implantaten." Diss., Ludwig-Maximilians-Universität München, 2013. http://nbn-resolving.de/urn:nbn:de:bvb:19-157420.
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Ziel der Studie war die Untersuchung des osseointegrativen Verhaltens von zylindrischen Zirkoniumdioxidimplantaten mit einer speziellen mikrorauen Oberfläche im Vergleich zu geometrisch identischen Ti-SLA Implantaten. Dazu wurden klinische, biomechanische und histologische bzw. histomorphometrische Untersuchungen am Miniaturschwein durchgeführt.
Nach Extraktion der Zähne 2 und 3 im Oberkiefer mit anschließender 6 monatiger Heilungsphase wurden 16 Miniaturschweinen insgesamt 96 Implantate implantiert. Jedes Tier erhielt 6 Implantate (3x ZrO2, 3x Ti-SLA). Nach 4, 8 und 12 Wochen Ein- heilphase erfolgte die Euthanasie der Tiere. Insgesamt konnten 59 Implantate den biomechanischen Ausdrehversuchen zugeführt und 28 Implantate histologisch bzw. histomorphometrisch untersucht werden.
Bei beiden Materialien zeigten sich peri-implantäre Infektionen und nach 4 bzw. 8 Wochen konnten bei den Ti-SLA Implantaten signifikant mehr krestale Knochenre- sorptionen nachgewiesen werden.
Die mittleren Ausdrehwerte für ZrO2 betrugen 42,4 Ncm nach 4 Wochen, 69,6 Ncm nach 8 Wochen und 69,3 Ncm nach 12 Wochen. Für Ti-SLA konnten zu den gleichen Untersuchungszeitpunkten jeweils Werte von 42,1 Ncm, 75,0 Ncm und 73,1 Ncm gemessen werden. Die biomechanischen Messungen ergaben zu keinem Zeitpunkt statistisch signifikante Unterschiede zwischen beiden Materialien.
Histologisch konnte an beide Materialien eine direkte Knochenanlagerung an die Im- plantatoberflächen beobachtet werden. Die Zirkoniumdioxidimplantate zeigten Bone Implant Contact-Werte von 27,1% nach 4 Wochen, 51,9% nach 8 Wochen und 51,1% nach 12 Wochen. Im Vergleich dazu betrugen die Werte der Titanimplantate 23,5%, 53,3% und 58,8%. Bezüglich der Bone Density variierten die Werte für ZrO2 zwischen 42,3%, 52,6% und 54,6% und für Ti-SLA zwischen 29,0%, 44,1% und 51,6%. Die histomorphometrischen Messungen ließen zu keinem der Untersu- chungszeitpunkte statistisch signifikante Unterschiede zwischen beiden Materialien erkennen.
Die Ergebnisse dieser Untersuchung führten zu der Erkenntnis, dass ZrO2-Implantate mit mikrorauer Oberfläche zumindest eine vergleichbare osseointegrative Kapazität besitzen wie Ti-SLA-Implantate.
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Colombo, John Samuel Lawrence. "The effects of surface modification on the osseointegration of titanium dental implants." Thesis, Cardiff University, 2010. http://orca.cf.ac.uk/55489/.
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In vitro , BMSCs cultured on M appeared more rounded, while they were more elongated on GB or TCP. BMSCs attached preferentially to M. The matrix formed appeared as a thin layer covering M, while matrix was thicker on the GB and TCP surfaces, infilling topographical features. Surface modification appeared to have little effect on the osteogenic activity of BMSCs. However, titanium was found to suppress differentiation down the adipogenic pathway and expression of inflammatory cytokines compared to plastic. Surface modification appeared to have little effect on osteoblasts activity or osseointegration, although roughened surfaces may provide better mechanical interlocking with bone. In vivo, no differences in the progression of osseointegration around any of the modified surfaces were observed. In DM, osteoblasts activity was altered and bone healing was delayed. There is therefore clearly scope to investigate surface modifications such as biomimetic coatings for use in compromised clinical situations.
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Alissa, Rami. "Clinical aspects and related factors influencing osseointegration and function of dental implants." Thesis, University of Manchester, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.516823.
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Alnsour, Hamza Mohammad Khaleel. "Role of the blood clot stabilization in early bone regeneration and osseointegration." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B46960399.
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Background: Blood clot formation is one of the first events in bone regeneration and osseointegration. The blood clot adheres to dental implants with hydrophilic surfaces more favorably than to those with hydrophobic surfaces. This appears to result in better bone healing and bone fill of defects around dental implants.
Objective: To assess the impact of blood clot stabilization at modSLA titanium implants on bone formation in chronic-type defects in a dog model.
Material & methods: Ten modSLA implants were installed in 5 dogs after creation of saddle-type buccal-lingual bony defects. In 5 implants (test sites), the blood clot was removed by sterile saline irrigation, while the clot was left undisturbed on the other 5 implants (control sites). After 8 weeks of healing, the animals were sacrificed and sections were prepared for histomorphometric analysis. The following measurements were performed: The residual defect length (DL), the buccal and lingual most coronal level of bone in contact with the implant (CBI-b and CPI-l), the new bone height (NBH), the percentage of bone to implant contact (BIC), the area of new bone fill (BF), the difference in buccal and lingual dimensions of CBI (D-CBI), and percentage of linear bone fill (PLF).
Results: the mean values of DL were similar in both groups (3.4 mm). All parameters assessed were consistently more favorable in control sites: CBI-b: 1.3 vs. 1.5, CBI-l: 1.3 vs. 0.8, D-CBI: -0.2 vs -0.5, NBH: 1.9 mm vs. 2.1 mm, PLF: 57.1% vs. 64.5% and BF: 4.4 mm? vs. 6.0 mm?. However, these differences were not statistically significant.
Conclusion: In the light of consistently more favorable parameters assessed for the healing of saddle-shaped bony defects around implants, it is assumed that a stabilized blood clot contributed to early bone regeneration and osseointegration. Undisturbed blood clot formation may, indeed, be a prerequisite for optimal treatment outcomes. However, owing to the small sample size in the present study, these tendencies ought to be explored in further studies.published_or_final_version
Dental Surgery
Master
Master of Dental Surgery
29
Goriainov, Vitali. "Bone and metal interface : an orthopaedic perspective on osseointegration of metal implants." Thesis, University of Southampton, 2016. https://eprints.soton.ac.uk/403880/.
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Introduction: The health care socio-economic environment is changing due to the population ageing, rising resultant functional impairment and patient quality of life expectations. These factors introduce increasing complexity of ensuing clinical scenarios, compelling a critical search for novel musculoskeletal regenerative and replacement strategies. Although joint arthroplasty is a highly effective treatment for arthritis, further innovation and refinement of uncemented implants are essential in order to improve implant integration and reduce the revision rate. This is critical within the current NHS environment of financial restraints and the drive to improve cost-effectiveness in arthroplasty. Methods: Biological skeletal stem cell (SSC)-mediated responses to surface nanotopographies were investigated. Passage one STRO 1 SSCs were cultured on nanotopographies in vitro, while in vivo examination of nanotopographies was conducted in subcutaneous mouse and calvarial rat models. Results: The following results were observed in relation to a range of surface modifying techniques: 1. Lithography -nanotopographies containing 20 nm tall pillars with near-square surface pattern arrangement generated significant enhancement of osteogenic gene induction (ALP, Collagen type I, OPN and OCN), osteogenic morphology and extracellular OPN synthesis in vitro and in vivo. In addition, histological evidence of collagen fibre organisation and early de novo mineralisation was observed in vivo. 2. Large Area Electron Beam melting -in vitro SSC osteogenic morphological alterations, bone matrix gene activation and OPN synthesis were directly correlated to the surface roughness within Ra range of 20-60 nm, with increasing Ra resulting in enhancement of osteogenic differentiation. 3. Thermal oxidation -nanowires 300 generated significant enhancement of osteogenic gene expression, osteogenic morphology, and OPN and Collagen type I protein synthesis in vitro. Significant enhancement of bone volume deposition at implant/bone interface was observed in vivo. 4. Electrochemical Jet Machining -nanotopographical elements of hierarchical scale texture triggered enhanced osteogenic gene expression. Conclusions: This work has demonstrated the ability of various nanotopographical surface-finishes to trigger an enhanced SSC-mediated osteogenic response, providing a clear rational for their potential application in orthopaedic implant.
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Cruz, Erin E. "OSSEOINTEGRATION OF TEMPORARY ANCHORAGE DEVICES USING RECOMBINANT HUMAN BONE MORPHOGENETIC PROTEIN-2." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/343.
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Over the past 5 years, the use of titanium implants as temporary anchorage devices (TADs) has become an important tool in clinical orthodontic practices. The use of TADs have provided orthodontists a way of moving teeth against fixed objects rather than against the surrounding teeth, which tend to counteract desired motion. At present, viable attachment of TADs involves direct insertion through gingival tissue and piercing of the bone. Surface modifications such as sandblasted and acid-etched treatment or bone morphogenetic protein surface treatment, however, can be applied to the TADs to promote enhanced osseointegration, thereby allowing the TADs to serve as stable anchors while avoiding bone puncture. In this study, a comparison was made between sandblasted/acid-etched TADs and sandblasted/acid-etched/recombinant human bone morphogenetic protein-2 (rhBMP-2) treated TADs to determine whether rhBMP-2 promotes enhanced osseointegration. A total of 10 rats (4 controls and 6 treated with rhBMP-2) were used in the study, with 1 TAD placed on the skull of each rat. At the end of 6 weeks, the animals were euthanized by carbon dioxide asphyxiation, and bone blocks, each containing a TAD, were prepared for histological examination and biomechanical characterization. The results of this study showed that TADs treated with rhBMP-2 had greater bone formation at the bone-implant interface and an increase in total implant stability.
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Guo, Yan, and 郭嬿. "Aspects of charge generation on Ti surface using a triboelectric approach." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/198841.
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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
32
De, Santis Enzo. "Reparação do tecido ósseo peri-implantar após enxerto ósseo autógeno e heterógeno : estudo experimental histológico em cães /." Araçatuba, 2011. http://hdl.handle.net/11449/103317.
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Orientador: Daniele BotticelliBanca: 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
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Alfarsi, Mohammed Adulrahman Mohammed. "The Effect of Titanium Dental Implants Surface Modification on the Macrophage Mediated Cell Response." Thesis, Griffith University, 2013. http://hdl.handle.net/10072/366744.
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Titanium dental implants are currently one of the best treatment alternatives for replacing missing teeth. The direct bond that forms between the jawbone and titanium in a process defined as osseointegration has made titanium the material of choice for such devices. Whilst the underlying biological mechanisms responsible for the osseointegration process have not been fully elucidated, high demand by both patients and clinicians has driven the clinical application of titanium implants.
Modification of the surface properties of titanium has been proven to be effective in promoting osseointegration, and thus understanding the fundamental cellular and molecular mechanisms responsible for the clinically observed outcomes as a result of titanium surface modification is the focus of considerable research. Previous research in this field has, as expected, focused on osteoblasts as they are the bone forming cells. This however, ignores the possible fundamental role of early mediators of the healing process, such as platelets and macrophages, which may interact with the implant surface well ahead of osteoblasts. As platelets and macrophages have well documented roles in modulating the function of other cells including osteoblasts, it is reasonable to postulate that the events that occur during the very early stages of the healing process may modulate repair in later stages, and ultimately influence the final osseointegration outcome.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Dentistry and Oral Health
Griffith Health
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Hacking, Steven Adam. "The effects of surface topography and chemistry on new bone formation and osseointegration /." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103160.
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The specific stimuli for osteogenesis are not clearly defined. It has been generally assumed that the chemical similarity of some biomaterials, such as hydroxyapatite and tri-calcium phosphate, to the mineral phase of bone generates a favorable osseous response. However, this does not account for the osseous response observed with a diverse range of metallic biomaterials that when placed in an osseous environment under appropriate conditions become osseointegrated. In this context, microtexture is essential for osseointegration; implants with irregularly microtextured surfaces (Ra 1-7 μm) are generally apposed by bone whereas those with polished surfaces (R a ≪ 0.5 μm) are generally apposed by fibrous tissue.Understanding the specific local stimuli for osteogenesis provides important information to optimize cementless implant design and new bone formation. This thesis suggests that surface topography is a specific local stimulus for osteogenesis as demonstrated in the context of in vivo and in vitro models.
To test the stimulatory effect of surface texture, a technique was developed to apply an irregular microtexture to sintered beaded porous coatings which doubled the amount of bone ingrowth. Another technique was developed to mask the chemistry of plasma sprayed hydroxyapatite without altering its topography. Plasma sprayed hydroxyapatite coatings possess a distinct microtexture comparable to that found on commercially available microtextured implants. In this in vivo model nearly 80% of the osseous response to hydroxyapatite coated implants was attributed to surface topography not chemistry.
Further studies were undertaken to determine if a biological analog existed for the rough irregular surfaces found on commercially available microtextured implants. A fracture model was developed that generated a range clinically observed of fracture types. Overall the different fracture surfaces possessed an irregular microtexture (Ra = 2.85 +/- 1.32 μm) that was not statistically different from those found on commercially available microtextured implants (Ra = 2-5 μm).
A novel method was developed to examine the response of pre-osteoblast cells to bone fracture surfaces. Disks of bone were fabricated from bovine tibia for in vitro study. A fractured surface was produced on these disks by splitting them with an osteotome. From each fractured disk pair, one half was polished to a smooth surface and the other left as fractured. A further subset of disks was produced by masking the surface chemistry with a nanometer thin layer of titanium using the technique previously described. Regardless of surface chemistry, bone or bone masked by titanium, formation of a mineralized matrix was observed only on the fractured surfaces. This suggested that the microtexture of the fracture surface may be a stimulus for new bone formation. Furthermore, the osseous response to microtextured implants may in fact be a response to what is perceived as a fracture surface.
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Salaie, Ranj. "Nano enhanced surface modification of titanium dental implants for improving osseointegration and biocompatibility." Thesis, University of Plymouth, 2018. http://hdl.handle.net/10026.1/13079.
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Dental implants are prone to bacterial colonisation and infection which subsequently cause dental implant failure. Coating the dental implant with an antibacterial agent and a biocompatible agent can inhibit the bacterial colonisation and infection without disturbing the biocompatibility of the implant. This study aimed to coat medical grade titanium alloy implants with silver and hydroxyapatite (HA) nanoparticles. The reason for using silver was to introduce antibacterial activity to the coated dental implants; and then using HA to preserve biocompatibility and manage the silver exposure of the primary human osteoblast cells. Medical grade titanium alloy discs measuring 15 mm in diameter were polished and silver plated to produce a uniform layer of silver nanoparticles on the surface. The electroplating method was followed by nano or micro HA deposition and curing at 500 °C to produce an HA coating and thereby achieving nano silver plus nano HA (Ag+nHA ), or nano silver plus micro HA (Ag+mHA), coatings on titanium alloy. The coating quality was assessed by electron microscopy. The bonding strength of the coating was investigated by the pull-off test and chemical stability in the cell culture media was studied by conducting dialysis and dissolution experiments. A series of experiments were conducted to investigate the biocompatibility of the coatings with primary human osteoblast cells over 7 days, cell health was assessed using biochemistry and microscopy. A differentiation experiment was conducted for 21 days to investigate the osteoblast cell mineralisation on the coatings and gene expression profile of the cells. Results showed that the specimens were successfully coated with nano silver and HA particles. The pull-off test showed that the coatings had reasonable bonding strength to the substrate. Dialysis and dissolution experiments showed that the coatings were stable in the cell culture media despite some silver release from the coatings. The biocompatibility experiments showed that there was a consistent amount of silver release (1-2 mg L-1) from the silver containing specimens. The human primary osteoblast cells were healthier on Ag+nHA compared to Ag and Ag+mHA over 7 days. The differentiation experiment showed that there was a constant silver supply over 21 days from all silver containing coatings. Cell viability over 21 days was significantly higher in Ag+nHA compared to Ag and Ag+mHA (p < 0.05). Moreover, the cells were mineralised and produced Ca2+ and P in all the treatments. In conclusion, Ag+nHA was more biocompatible compared to Ag and Ag+mHA and can have a potential for clinical use.
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Shi, Yu Chen. "Surface coating of macrophage-regulatory zymosan polysaccharides for enhanced osseointegration on dental implants." Thesis, University of Macau, 2018. http://umaclib3.umac.mo/record=b3952177.
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BARBERI, JACOPO. "Exploring proteins in Roughland: on the adsorption of proteins on biomaterials for osseointegration." Doctoral thesis, Politecnico di Torino, 2022. http://hdl.handle.net/11583/2970986.
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Esteves, Jônatas Caldeira [UNESP]. "Efeito de três sistemas de osteotomia - ultrassom cirúrgico, laser Er, Cr: YSGG e sistema rotatório - sobre o processo de osseointegração e reparo de defeitos ósseos em tíbia de ratos: estudo histomorfométrico, imuno-histoquímico e biomecânico." Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/114048.
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000805961.pdf: 4843456 bytes, checksum: f128a369968d68e92229dadbd28be7df (MD5)O objetivo deste trabalho foi avaliar o processo de reparo ósseo e a osseointegração de implantes inseridos em leitos cirúrgicos preparados por meio de Brocas Convencionais, Ultrassom Piezoelétrico e LASER Er,Cr:YSGG. Como objetivo secundário, foi testada a habilidade do ultrassom cirúrgico de estumilar a liberação de citocinas e fatores de crescimento ósseo durante o processo de reparo. Para tanto, dois estudos distintos foram conduzidos. No Estudo 1, 144 ratos foram divididos em 3 grupos (Grupos Broca, LASER e Piezo) com 48 animais cada. Mini implantes usinados foram instalados em ambas as tíbias de cada animal em alvéolos cirúrgicos preparados pelos 3 sistemas testados de acordo com o grupo ao qual o animal pertencia Após a intervenção cirúrgica, 8 animais por grupo foram sacrificados aos 0, 3, 7, 14, 30 e 60 dias pós-operatórios.. O implante da tíbia direita foi utilizado para o ensaio de torque de remoção e o da tíbia esquerda, para análise de Contato-Osso-Implante (COI) e Fração de Área Ocupada por Osso (FAOO). No Estudo 2, 174 animais foram divididos nos mesmos grupos experimentais – Broca, Piezo e Laser – com 63, 63 e 48 animais cada, respectivamente. Defeitos ósseos de 2mm de diâmetro foram produzidos na tíbia direita dos animais usando um dos três dispositivos testados de acordo com o grupo ao qual o animal foi designado. Oito animais de cada grupo foram sacrificados aos 0, 3, 7, 14 30 e 60 dias e a cicatrização óssea foi analisada por histomorfometria e detecção imuno-histoquímica de Osteocalcina, Osteoprotegerina, Rankl, Vegf e Caspase-3. Cinco animais dos Grupos Broca e Piezo foram sacrificados aos 3, 7 e 14 dias e o espécimes coletados foram utilizados para análise de PCR quantitativo (Q-PCR). Os resultados do Estudo 1 demonstraram a osseointegração dos implantes no três grupos estudados. No Grupo Broca a formação óssea ocorreu mais precocemente, porém um aumento significativo no...
The aim of this study was to evaluate the bone healing process and osseointegration of implants placed in sockets prepared by conventional Drills, Piezosurgery and Er,Cr:YSGG laser. As a secondary objective we tested the hability of Piezosurgery of enhancing the bone repair by releasing of citokynes and growth factor. Therefore, two different studies were conducted. In study 1, 144 rats were assigned to 3 groups: Groups Drill, Laser and Piezo, with 48 animals in each group. Machined mini-implants were placed in both tibiae of each animal in sockets prepared by the three tested systems, according to the group in which it was assigned. After the surgical procedures, 8 animals were sacrificed postoperatively at 0, 3, 7, 14, 30 and 60 days in each group. The implant of the right tibia was used for removal torque test and the left tibia implant was used for Bone-to-Implant Contact (BIC) and Bone Area Fraction Occupancy (BAFO) analysis. In Study 2, 174 animals were ssigned to the same experimental Goups - Drill, Piezo and Laser – with 63, 63 and 48 animals in each group. Bone defects with 2mm in diameter were created in the righ tibia of each animal using one of the three tested devices according to the group in which it was assigned. Eight animals of each group was sacrificed at 0, 3, 7, 14 , 30 and 60 days and bone healing were analyzed by means of histomorphometry and immunohistochemical detection of Osteocalcin, Osteoprotegerin, Rankl, Vegf and Caspase-3. Also, 5 animals form Gorups Drill and Piezo were sacrificed at 3, 7 and 14 days and the bone samples were used for quantitative PCR (Q-PCR) analysis. Results of Study 1 demonstrated implant osseointegration in all experimental groups. The Group Drill presented early bone formation, however, significant increasing in torque removal values occurred only at 30 days. In Groups Laser and Piezo, removal torque increased early and bone healing around the implant was progressively increased until...
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Wong, Chi-tak, and 黃志德. "Osteoconduction and osseointegration of a strontium-containing hydroxyapatite bioactive bone cement: invitro and in vivo investigations." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B29940631.
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Al-Khayyat, Farah Nabeel Mohammed Tahir. "Surface modification of titanium implants by grit-blasting with novel bioactive glasses." Thesis, Queen Mary, University of London, 2018. http://qmro.qmul.ac.uk/xmlui/handle/123456789/33943.
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Introduction: The survival of dental implants depends on osseointegration. Modifications to the implant surface are attractive for promoting the success of the implant. Abrading the surface of the implant with bioactive glass is an attractive option for improving the speed of osseointegration. Aims: To develop a bioactive glass that has the ability to enhance the surface roughness of the implant by embedding particles into the surface and to investigate the effect of grit blast parameters on the removal of the titanium from the surface. Methods: Three glasses based on SiO2-CaO-Na2O-P2O5-CaF2 were synthesized by a melt quench technique. The glasses were characterised and investigated for their bioactivity. Titanium discs were abraded with coarse glass particles by using a grit blast technique with different parameters, such as, distance, air pressure and speed. The depth, width of the abraded line and surface roughness (Ra) were measured by light profilometer. The distribution of the glasses on the titanium surface was measured by SEM-EDX. The biocompatibility of the abraded discs was tested in vitro using MC3T3-E1 cell line. Results: All glasses exhibited an amorphous structure with varied bioactivity. Changing the abrasion parameters influenced the amount of titanium removed and the surface coverage. The harder the glass the lower the amount of titanium removed and the wider the width of the abraded area. The Ra was significantly increased from 0.1μm to 1.6μm. The SEM-EDX analysis confirmed that the glasses were widely distributed and a higher coverage was seen with the harder glass. The abraded discs showed good biocompatibility in vitro. Conclusions: The designed compositions were successfully modifying the surface of the titanium. They are abrasive enough to significantly embed into the titanium surface by using the grit blast technique and increase their surface roughness. TheIntroduction: The survival of dental implants depends on osseointegration. Modifications to the implant surface are attractive for promoting the success of the implant. Abrading the surface of the implant with bioactive glass is an attractive option for improving the speed of osseointegration. Aims: To develop a bioactive glass that has the ability to enhance the surface roughness of the implant by embedding particles into the surface and to investigate the effect of grit blast parameters on the removal of the titanium from the surface. Methods: Three glasses based on SiO2-CaO-Na2O-P2O5-CaF2 were synthesized by a melt quench technique. The glasses were characterised and investigated for their bioactivity. Titanium discs were abraded with coarse glass particles by using a grit blast technique with different parameters, such as, distance, air pressure and speed. The depth, width of the abraded line and surface roughness (Ra) were measured by light profilometer. The distribution of the glasses on the titanium surface was measured by SEM-EDX. The biocompatibility of the abraded discs was tested in vitro using MC3T3-E1 cell line. Results: All glasses exhibited an amorphous structure with varied bioactivity. Changing the abrasion parameters influenced the amount of titanium removed and the surface coverage. The harder the glass the lower the amount of titanium removed and the wider the width of the abraded area. The Ra was significantly increased from 0.1μm to 1.6μm. The SEM-EDX analysis confirmed that the glasses were widely distributed and a higher coverage was seen with the harder glass. The abraded discs showed good biocompatibility in vitro. Conclusions: The designed compositions were successfully modifying the surface of the titanium. They are abrasive enough to significantly embed into the titanium surface by using the grit blast technique and increase their surface roughness. The glass abraded discs show both good bioactivity and biocompatibility in vitro.
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Esteves, Jônatas Caldeira. "Efeito de três sistemas de osteotomia - ultrassom cirúrgico, laser Er, Cr: YSGG e sistema rotatório - sobre o processo de osseointegração e reparo de defeitos ósseos em tíbia de ratos : estudo histomorfométrico, imuno-histoquímico e biomecânico /." Araraquara, 2014. http://hdl.handle.net/11449/114048.
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Orientador: Elcio Marcantonio JuniorBanca: Roberto Henrique Barbeiro
Banca: Wilson Roberto Poi
Banca: Thalita Pereira Queiroz
Banca: Paulo Tambasco de Oliveira
Resumo: O objetivo deste trabalho foi avaliar o processo de reparo ósseo e a osseointegração de implantes inseridos em leitos cirúrgicos preparados por meio de Brocas Convencionais, Ultrassom Piezoelétrico e LASER Er,Cr:YSGG. Como objetivo secundário, foi testada a habilidade do ultrassom cirúrgico de estumilar a liberação de citocinas e fatores de crescimento ósseo durante o processo de reparo. Para tanto, dois estudos distintos foram conduzidos. No Estudo 1, 144 ratos foram divididos em 3 grupos (Grupos Broca, LASER e Piezo) com 48 animais cada. Mini implantes usinados foram instalados em ambas as tíbias de cada animal em alvéolos cirúrgicos preparados pelos 3 sistemas testados de acordo com o grupo ao qual o animal pertencia Após a intervenção cirúrgica, 8 animais por grupo foram sacrificados aos 0, 3, 7, 14, 30 e 60 dias pós-operatórios.. O implante da tíbia direita foi utilizado para o ensaio de torque de remoção e o da tíbia esquerda, para análise de Contato-Osso-Implante (COI) e Fração de Área Ocupada por Osso (FAOO). No Estudo 2, 174 animais foram divididos nos mesmos grupos experimentais - Broca, Piezo e Laser - com 63, 63 e 48 animais cada, respectivamente. Defeitos ósseos de 2mm de diâmetro foram produzidos na tíbia direita dos animais usando um dos três dispositivos testados de acordo com o grupo ao qual o animal foi designado. Oito animais de cada grupo foram sacrificados aos 0, 3, 7, 14 30 e 60 dias e a cicatrização óssea foi analisada por histomorfometria e detecção imuno-histoquímica de Osteocalcina, Osteoprotegerina, Rankl, Vegf e Caspase-3. Cinco animais dos Grupos Broca e Piezo foram sacrificados aos 3, 7 e 14 dias e o espécimes coletados foram utilizados para análise de PCR quantitativo (Q-PCR). Os resultados do Estudo 1 demonstraram a osseointegração dos implantes no três grupos estudados. No Grupo Broca a formação óssea ocorreu mais precocemente, porém um aumento significativo no...
Abstract: The aim of this study was to evaluate the bone healing process and osseointegration of implants placed in sockets prepared by conventional Drills, Piezosurgery and Er,Cr:YSGG laser. As a secondary objective we tested the hability of Piezosurgery of enhancing the bone repair by releasing of citokynes and growth factor. Therefore, two different studies were conducted. In study 1, 144 rats were assigned to 3 groups: Groups Drill, Laser and Piezo, with 48 animals in each group. Machined mini-implants were placed in both tibiae of each animal in sockets prepared by the three tested systems, according to the group in which it was assigned. After the surgical procedures, 8 animals were sacrificed postoperatively at 0, 3, 7, 14, 30 and 60 days in each group. The implant of the right tibia was used for removal torque test and the left tibia implant was used for Bone-to-Implant Contact (BIC) and Bone Area Fraction Occupancy (BAFO) analysis. In Study 2, 174 animals were ssigned to the same experimental Goups - Drill, Piezo and Laser - with 63, 63 and 48 animals in each group. Bone defects with 2mm in diameter were created in the righ tibia of each animal using one of the three tested devices according to the group in which it was assigned. Eight animals of each group was sacrificed at 0, 3, 7, 14 , 30 and 60 days and bone healing were analyzed by means of histomorphometry and immunohistochemical detection of Osteocalcin, Osteoprotegerin, Rankl, Vegf and Caspase-3. Also, 5 animals form Gorups Drill and Piezo were sacrificed at 3, 7 and 14 days and the bone samples were used for quantitative PCR (Q-PCR) analysis. Results of Study 1 demonstrated implant osseointegration in all experimental groups. The Group Drill presented early bone formation, however, significant increasing in torque removal values occurred only at 30 days. In Groups Laser and Piezo, removal torque increased early and bone healing around the implant was progressively increased until...
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Villaça-Carvalho, Maria Fernanda Lima. "Efeito na osseointegração de um novo método de nanotexturização de superfície de implantes através de anodização /." São José dos Campos, 2016. http://hdl.handle.net/11449/136439.
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Orientador: Mari Eli Leonelli de MoraesCo-orientador: Luana Marotta Reis de Vasconcellos
Banca: João Paulo Barros Machado
Banca: Natal Nerímio Regone
Banca: Maria Aparecida Neves Jardini
Banca: Sergio Lucio Pereira de Castro Lopes
Resumo: A Implantodontia é uma das áreas da Odontologia que mais tem evoluído nas últimas décadas. Diversos estudos são desenvolvidos na intenção de otimizar o processo de osseointegração utilizando a nanotopografia na superfície dos implantes. Atualmente o processo de anodização da superfície vem se destacando entre estas técnicas. Desta forma, o objetivo nesta pesquisa foi obter nano rugosidades e fase de anatase em implantes odontológicos de Titânio, buscando a otimização da osseointegração. Sessenta implantes foram caracterizados quanto à morfologia, por meio de microscopia de força atômica (AFM) e Microscopia Eletrônica de Varredura (MEV); quanto à composição química, por análise por detector de espectrometria por espalhamento de energia (EDS) e Espectroscopia Raman; e por fim, quanto ao potencial de corrosão, pela análise de impedância eletroquímica (EIE). A osteogênese, in vivo, foi comparada por Radiografia periapical (RP), Microtomografia Computadorizada (µTC) e teste de remoção por torque reverso; e, a análise in vitro, foi realizada por teste de citotoxicidade por MTT [(brometo de 3-4,5-dimetiltiazol-2-il)-2,5-difeniltetrazoliol]. Os implantes foram divididos em: G1 (controle); Grupo 2 (jateado); Grupo 3 (anodizadoexperimental). Cada coelho recebeu um implante de cada grupo nas tíbias direita e esquerda, e cinco coelhos, foram eutanasiados 2 e 6 semanas após a cirurgia. Os implantes da tíbia direita foram submetidos à RP e à µTC; e os da tíbia esquerda, ao teste de torque reverso e análise de citotoxicidade por MTT. AFM e MEV comprovaram a presença de nano rugosidades na superfície em G3; análises de EDS e Espectroscopia Raman, demonstraram aumento da camada do filme de TiO2 e a obtenção de anatase em G3. Na RP, nenhum implante apresentou halo radiolúcido. Na µTC, G3 foi sempre superior aos demais grupos nos parâmetros observados: BV, BV/TV, Tb.Th. No teste de torque reverso, houve...
Abstract: The Implantology is one of the areas of dentistry that has most evolved in recent decades. Many studies have been developed with the intention of optimizing the osseointegration process using nanotopography on the surface of the implants. Currently the surface of the anodizing process has stood out among these techniques. Thus, the aim of this research was to obtain nano roughness and anatase phase in dental Titanium implants, seeking for the optimization of the osseointegration. Sixty implants were characterized for morphology by atomic force microscopy (AFM) and Scanning Electron Microscopy (SEM); in chemical composition, by mass spectrometry detector energy scattering (EDS) and Raman spectroscopy; and finally, as the potential for corrosion, the electrochemical impedance analysis (EIS). Osteogenesis in vivo was compared by Periapical Radiography (PR), Computed Microtomography (μTC), removal reverse torque test; and in vitro analysis, it was performed by MTT cytotoxicity assay [(bromide 3-4,5-dimethylthiazol-2-yl) -2,5-difeniltetrazoliol]. The implants were divided into G1 (control); Group 2 (sandblasted); Group 3 (anodized-experimental). Each rabbit received an implant of each group in the right and left tibias and five rabbits were euthanized 2 and 6 weeks after surgery. The implants of the right tibia underwent PR and μTC; and the left tibia, the reverse torque test and MTT cytotoxicity assay. AFM and SEM confirmed the presence of nano roughness on the surface in G3; EDS analysis and Raman spectroscopy showed increased TiO2 film layer and obtainment of anatase G3. In PR, no implant presented radiolucent halo. In μTC, G3 has always been higher than the other groups in the observed parameters: BV, BV / TV, Tb.Th. In the reverse torque test, It was required greater removal force of anodized implants. In the MTT test, the experimental implants were nontoxic to cells. It was conclude that the anodizing process used in this study...
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Ni, Ming. "The mechanism of osteoinduction by nacre : effects of soluble proteins and insoluble matrix /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/9831.
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Mousllie, Sadiqu al. "Die Osseointegration von Implantaten in Extraktionsalveolen in Abhängigkeit von der Wundversorgung eine tierexperimentelle Untersuchung /." [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=968409792.
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Kim, James H., and n/a. "A comparison of osseointegration in conventionally versus immediately restored implants in a sheep model." University of Otago. School of Dentistry, 2007. http://adt.otago.ac.nz./public/adt-NZDU20071206.162016.
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Objectives: To compare the osseointegration of conventionally and immediately restored tapered implants in a split-mouth animal model, and to compare different methods of analysis for measuring osseointegration.
Materials & Methods: Twenty tapered implants were placed in the posterior mandibles of ten sheep, three months after premolar extractions. Ten control implants were placed and were restored after three months submerged healing. Ten test implants were placed on the contralateral side at this time and immediately restored. Animals were sacrificed after a further three months healing. Resonance frequency analysis (Implant Stability Quotient, ISQ), and standardized radiographs were taken at all stages. Alveolar bone height relative to the implant shoulder was measured on digitized radiographs. Histomorphometric and micro-Computed Tomograph ([mu]CT) morphometric analysis for Bone-to-Implant Contact (BIC) and Bone Density (BD) were performed. Radiographic, stability and morphometric measurements were compared statistically.
Results: Only three (30%) of conventionally restored and two (20%) immediately restored implants survived (p = 0.74). Mean crestal bone level after three months loading differed significantly (control 5.3 � 0.9 mm versus test 0.9 � 1.3 mm; p = 0.02). Control implants lost more crestal bone over three months than test implants but this was not statistically significant (3.5 � 1.0 mm versus 0.7 � 1.0 mm; p = 0.06). The test group showed a higher mean ISQ value (85.4 � 6.9) compared to the control group (72 � 14.4; p = 0.349). Both groups showed a slightly reduced stability during the loaded period. This was more marked for the test group but not statistically significant (-0.5 � 3.8 ISQ versus -4.35 � 6.6 ISQ; p = 0.8). A statistically significant negative correlation was found between the loss of crestal bone and ISQ with loading (Pearson�s coefficient of correlation r = -0.473 p = 0.026). Both groups showed a statistically significant difference in BIC for both histomorphometric analaysis (HMA); p = 0.039 and [mu]CT morphometric analysis; p = 0.013. When the two forms of morphometric analysis were compared, HMA and [mu]CT morphometric analysis differed significantly for both BIC (p = 0.05) and BD (p = 0.048). However, a statistically significant correlation was found between the two measuring techniques, for both BIC (r = 0.335 p = 0.013) and BD (r = 0.439 p = 0.01).
Conclusions: The placement of wide-bodied 3i Osseotite NT[TM] tapered implants into sheep mandible resulted in high failure rate regardless of the loading protocol. The sheep mandibular model may be inappropriate as a model for evaluation of immediate loading, and to test implants which are designed for soft bone. Further investigations are needed to look into the variations in bone microstructure along with their impact on the mechanics of implant-bone union. Although a statistically significant difference was found between the two measurement techniques, a positive correlation was found between HMA and [mu]CT morphometric analysis suggesting non-invasive methods may have a potential in assessing osseointegration. Further research is required to optimize the variables in [mu]CT analysis, such as, voltage, filters, and thresholding to minimize artifacts and to maximize bone contrast when titanium implants are present.
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Guben, Tamara Heidi. "Bone quality in osseointegration : a biomechanical study, using the rat tibia, and clinical evaluation." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0004/MQ44175.pdf.
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Lutz, André [Verfasser]. "Ein integrales Modellierungskonzept zur numerischen Simulation der Osseointegration und Langzeitstabilität von Endoprothesen / André Lutz." Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover (TIB), 2012. http://d-nb.info/1021186473/34.
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Shinawi, Lana Ahmed. "Ion implantation as a route to enhanced osseointegration : fundamental studies of modified titanum surfaces." Thesis, University College London (University of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.406385.
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Karnatz, Nadia [Verfasser]. "Vergleichende Untersuchungen zur Osseointegration nach Photofunktionalisation und Oberflächenplasmaaktivierung dentaler Titanimplantate im Landschwein / Nadia Karnatz." Hamburg : Staats- und Universitätsbibliothek Hamburg Carl von Ossietzky, 2020. http://d-nb.info/1222163284/34.
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Bayreuther, Katja [Verfasser]. "Eine fluoreszenz- und lichtmikroskopische Untersuchung der Osseointegration von WI.TAL-Implantaten am Schweinekiefer / Katja Bayreuther." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2009. http://d-nb.info/1023579898/34.
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