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| Author | : 蔡淳淳 |
| Publisher | : |
| Total Pages | : 48 |
| Release | : 2011 |
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| Author | : Ceren Gokmenoglu |
| Publisher | : |
| Total Pages | : |
| Release | : 2017 |
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Modification of titanium dental implants are of great interest to enhance osseointegration and may provide successful long-term results. Boron nitride (BN), with its physical properties and beneficial effects on bone formation and composition, can be a promising material as a coating substance. The aim of this study was to evaluate osseointegration of BN coated implants both histomorphometrically and biomechanically on a rabbit model. BN has been coated two different coating thicknesses by using RF magnetron sputtering system. Totally fifty four implants were inserted into the tibiasu2019 of 12 New Zealand rabbits. Implants were placed bilaterally into the tibias under general anesthesia. All animals were sacrificed using intravenous sodium pentobarbital after 4 weeks. For the implants used for histomorphometric evaluation, bone-implant contact (BIC) percentages and new bone area / total area (BATA) were calculated. The removal torque (RT) test was performed and the highest removal torque required for creating a fracture between the implant and bone was measured. Through the histomorphometric evaluations, the highest BIC percentages were observed in the control group, whereas the micro scale (micro-coated) BN group had a lower but comparable BIC level with the control group. In the nano-scale (nano-coated) BN group, the BIC percentages were low. The bone tissue in the medullary cavity was the highest in the nano-scale BN group, whereas the lowest values were observed in the control group. The RT values measured in all groups were found low, but the highest RT values torque was observed in the control group. As a result, no inflammatory problem developed around any implant. Osseointegration occurred around all control and BN-coated implants. This research was supported by The Scientific and Technical Research Council of Turkey (TUBITAK) with the project no 114S391.
| Author | : Lin Guo-Fen |
| Publisher | : |
| Total Pages | : |
| Release | : 2017 |
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Background (500 characters max.)Implant failure may occur in patients with osteoporosis, especially in elderly over 50 years including postmenopausal females1. This osteoporosis leads to insufficient bone-implant contact and can severely deteriorate the primary stability and osseointegration establishment of dental implant. Recently, the positive effects of Strontium (Sr) iron on inhibiting bone resorption and promoting bone formation have been elucidated in numerous studies. Our previous in vitro and vivo studies incorporated Sr iron onto the surface of SLA implant by hydrothermal treatment, and the results demonstrated that Sr-incorporated surfaces has a positive influence on mesenchymal stem cell (MSC) differentiation and enhancing implant osseointegration in healthy animals2.Aim/Hypothesis (300 characters max.)The aim of this study was designed to compare the osseointegration behavior of conventional SLA implants and Sr-SLA implants in ovariectomized rabbits.Materials and Methods (1000 characters max.)Thirty-two New Zealand rabbits, half of which were carried out with bilateral ovariectomy and glucocorticoid administration for six weeks (OVX group), and another 16 rabbits were conducted with SHAM operation as for control group. Bone mineral density of lumbar spines (L3u2013L5), global knee bone and subchondral bone was measured before and after ovariectomy or SHAM operations using dual energy X-ray absorptiometry (Fig.1). After successful osteoporotic-induced model, the SLA and Sr-SLA implants were randomly inserted into the tibia and femur metaphysis of each animal. The rabbits were respectively sacrificed 3 and 6 weeks after dental implant placement. The samples from femur metaphysis in each group at each time point were subjected to removal torque testing, and the remaining samples from tibia metaphysis were conducted for histomorphometric analysis3.Results (1000 characters max.)At the end of the healing period, all implants were osseointegrated and histologically in direct contact with the surrounding bone. The Sr-SLA implants displayed closer contact and much more newly formed bone than the SLA implants (Fig.2). At 3 weeks (Fig.3), the removal torque values (RTV) of the Sr-SLA implants were significantly higher than those of the SLA implants in both OVX (P
| Author | : Junyuan Li |
| Publisher | : Open Dissertation Press |
| Total Pages | : |
| Release | : 2017-01-27 |
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| ISBN | : 9781361385210 |
This dissertation, "Effects of Surface-modified Titanium Implants on Osseointegration in Irradiated Bone" by Junyuan, Li, 黎俊媛, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Radiotherapy is a common treatment for head and neck cancers. However, it compromises bone healing. Titanium implanthas been shown to be a predictable method for replacing missing teeth. Clinical studies revealed that implant failure rate in irradiated regionwas high. Many studies showed that modifications of implant surface could enhance implant osseointegration by improving cell attachment, cell growth and bone formation. Nevertheless, there were few studies investigating the effect of implant surface modification on osseointegration in irradiated bone. In the first experiment, the effect of fluoride-modified (FM) titanium surface on irradiated osteoblast attachment was assessed. The morphology and chemical composition of FM surface was assessed by SEM, AFM and XPS. Osteoblasts received 0Gy, 2Gy, 4Gy, 6Gy, 8Gy, 10Gy radiation. Cell number, fluorescence intensity and cell area of irradiated osteoblasts were assessed. The number of osteoblasts onFM surface was fewer than those on NF surface after 0Gy, 2Gy, 8Gy and 10Gy radiation. Cell area of osteoblasts on FM surface was less at 2Gy radiation but larger at 6Gy radiation than on NF surface. The fluorescence intensity of osteoblasts was also higher on NF surface than on FM surface after receiving 0Gy, 2Gy, 4Gy, 10Gy radiation. In the second experiment, an animal model was established to study the effect of radiation on osseointegration. Rabbits were divided into 15Gy and 30Gy radiation groups. Only the left leg was exposed to radiation, and the right leg was protected from radiation. Totally, 24 implants were inserted. Implant stability quotient (ISQ), bone volume to total volume (BV/TV), bone-to-implant contact (BIC), and bone growth rate were measured. After 15Gy and 30Gy of radiation, ISQ and BV/TV were significantly reduced. At week 3, 15Gy radiation group displayed slower bone growth rate comparing with the control side. Fluorochrome results showed that the 30Gy radiation side had a significantly slower apposition of new bone.In addition, BIC on30Gy radiation side was notablypoorer than that on 15Gy radiation side and on 30Gy control side. Based on the animal model, the third experiment investigated effects of calcium phosphate nanocrystals on implant osseointegration in irradiated bone. Titanium implants treated with nano-scale calcium phosphate (CaP) crystals served as the test group while ones with dual acid-etching only served as the control group. The left leg of rabbits received 15Gy radiation and implants were placed in the irradiated leg. Significant higher ISQ was detected in the nano-CaP group at week 12. The bone growth rate in nano-CaP group was more than doubled than the control group at both week 6 and week 9. The fourth experiment evaluated artifacts on micro-CT images caused by titanium dental implant. Implants were assigned into four groups: (1) implant only; (2) implant with covering screw; (3) implant with resin embedding; and (4) implant with covering screw and resin embedding. Each implant was scanned by micro-CT at 3 angulations. Implant angulation was the most determining factor followed by resin embedding. Minimal metallic artifacts were obtainedin non-embedded implants with its axis paralleling to X-ray. DOI: 10.5353/th_b5312315 Subjects: Osseointegration Dental implants
| Author | : Sutton E. Wheelis |
| Publisher | : |
| Total Pages | : 0 |
| Release | : 2022 |
| Genre | : Biocompatibility |
| ISBN | : |
Although titanium (Ti) dental implants are known to achieve high success rates and osseointegration in vivo, a higher incidence of implant failures have been recently reported. Implant failures are caused by several factors; however, the nature and intensity of the inflammatory response at the titanium-tissue interface determines the healing outcome of an implant. Surface modifications performed on titanium implants have attempted to directly address both patient and external factors that interfere with constructive inflammation, but often do not address multiple complications that impact osseointegration while maintaining regenerative healing. Dicationic imidazolium-based ionic liquids (IonL) have demonstrated low toxicity, antimicrobial, lubricant, and anticorrosive activities in vitro making them a potential candidate as a multifunctional dental implant coatings. However, the biological response to these coatings in vivo is unknown. The goal of this dissertation was to evaluate the effect IonLs have on inflammation, healing, and osseointegration of titanium dental implants. This research is divided into three aims (i) to investigate the biocompatibility of IonL in a subcutaneous model, (ii) to define and validate success criteria for an oral implantation model and (iii) to investigate the impact of IonL on early healing and osseointegration in an oral implantation model. In each aim a combination of clinical evaluation, histopathology, immunohistochemistry, molecular analysis, and MicroCT was used to track inflammation and healing from 2-30 days (d) in the Lewis rat. In aim 1, an initial evaluation of both IonL-Phe and IonL-Met indicated that IonL appeared in peri-implant tissues and increased acute inflammation at 2d compared to uncoated Ti. At 14d, inflammation receded with more developed peri-implant tissue in coated and uncoated samples with no foreign body giant cells. IonL was no longer observed at 14d, suggesting elution or resorption by macrophages. This aim demonstrated that medium dose IonL-Phe does not significantly interfere with Ti foreign body response in an aseptic environment. In aim 2, a new pre-clinical oral implantation model defined an appropriate baseline for successful Ti osseointegration. Healing was similar to other rodent models: hematoma and acute inflammation at 2d, initial bone formation at 7d, advanced bone formation and remodeling at 14d, and bone maturation at 30d. Overall, this model resulted in a 78.5% osseointegration success rate (>60% bone-to-implant contact (BIC)), similar to human osseointegration. Therefore, This model combines the advantages of a rodent model while maximizing BIC, making it an excellent candidate for evaluation of IonLs. Following aim 2, a pilot in vivo assessment determined medium dose IonL-Phe demonstrated the best histogical response and BIC for the remaining evaluation. In aim 3, IonL-Phe-coated and uncoated cpTi screws were implanted into several demographic groups of rats to represent biological variations that could affect healing. Molecular and histological analysis indicated IonL heightened acute inflammation compared to uncoated Ti. However, the coating was released/resorbed by 7 days and did not negatively affect subsequent bone remodeling in all demographics. Overall, IonL-Phe coating did not disturb oral Ti osseointegration and may provide additional control over the healing environment in scenarios known to be challenged by bacteria, such as peri-implantitis
| Author | : James Eric Ho |
| Publisher | : |
| Total Pages | : 384 |
| Release | : 2006 |
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| Author | : Dr. Sandeep Gurav |
| Publisher | : |
| Total Pages | : |
| Release | : 2017 |
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Background: Despite the advances in additive and subtractive implant surface modifications, there is a need and scope for novel biomaterials enabling early osseointegration. A dual-optimization approach synergizing osteoinductive and osteoconductive chemicals has been applied to develop a novel bio-material.Aim: To compare osseointegration in rabbit between osteogenic nanofibrous-coated (ONFC) dental implants and uncoated titanium fixtures.Materials and Method: Individual bio-active ingredients were dissolved in trifluoroethanol to obtain Polycaprolactone-gelatin scaffold. This was electro-spun around the surface of a titanium screw to obtain an osteogenic nanofibrous coating which was characterized by thermal, physical, x-ray diffraction and biologic analyses. A pilot study involving placement of ONFC-implants and uncoated titanium fixtures in the tibia of a single, skeletally mature male New Zealand white rabbit was conducted. Observations were recorded at the end of six weeks. A further detailed study was conducted on seven rabbits to validate these results at the end of twelve weeks.Results and Conclusion: Radiological (x-ray and micro CT scan), histo-morphological and ultrastructural analyses of the interfacial tissues suggested that ONFC-implants showed enhanced osseointegration.
| Author | : Hao Zhang |
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| Total Pages | : |
| Release | : 2017 |
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Abstract:Titanium surfaces have been constantly modified to improve bioactivity and osseointegration. In this study, we modified titanium surfaces through hydrothermal treatment with a mixed solution of phytic acid and calcium hydroxide, then evaluated their bioactive and osteogenic activities. In vitro tests, calcium-decorated titanium surface enhanced the cell adhesion, proliferation and osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs). In vivo tests, Micro- CT and histological evaluations indicated that the modified implants promoted new bone formation and osseointegration between the implants and the host bone. These findings provided evidence that this simple modification would be promising solution to improve bioactivity and osseointegration, which would be beneficial not only for titanium implants but also other implanted biomaterials.Background: Titanium (Ti) or titanium alloys coated with various bioactive calcium phosphates (CaPs), including hydroxyapatite (HA) and u03b2-tricalcium phosphate (u03b2-TCP), are considered as satisfactory implant materials. CaP coatings provide nanostructural or microstructuctural characteristics on titanium or titanium alloys, thereby increasing the adhesion of osteoblasts, which enhance the osseointegration and shorten the healing time.Aim: To prepare and evaluate the effect of calcium-containing chemical conversion coating on promoting new bone formation and early osseointegration in vivo.Material and methods: We designed and prepared a phytic acid/calcium hydroxide composite coating on the pure titanium implant (Ti-SLA-2/10) through hydrothermal treatment with a mixed solution of phytic acid (PA) and saturated calcium hydroxide solution [Ca (OH)2]. The pure titanium implant with a sandblasted/acid-etched (SLA) surface was used as the control group (Ti-SLA). The surface morphology, elemental composition, surface roughness, wettability, and calcium ion release were investigated separately. Twenty-four SLA and calcium-containing SLA implants were immediately inserted into the mandibles of twelve New Zealand white rabbits. The biological effects were evaluated by Micro-computed tomography (Micro-CT) analysis and histological evaluation after 1, 2, and 4 weeks of healing. Results: Phytic acid/calcium hydroxide composite coating with superior hydrophilicity were successfully prepared on titanium implants. The surface characteristics showed Ti-SLA-2/10 implants with multiple pits and craters can release calcium ions continuously. In vivo, the volume of new bone around the Ti-SLA-2/10 implants was significantly higher than that of the Ti-SLA implants, but more fibrous tissue was observed surround the Ti-SLA implants after 1 week of healing. The Ti-SLA-2/10 implants showed higher bone volume fraction (bone volume/total volume, BV/TV, %) than that of the Ti-SLA implants at each time points (p
| Author | : 徐政忠 |
| Publisher | : |
| Total Pages | : 51 |
| Release | : 2013 |
| Genre | : |
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| Author | : Ellen Elizabeth Sauter |
| Publisher | : |
| Total Pages | : 140 |
| Release | : 2013 |
| Genre | : Artificial joints |
| ISBN | : |
Currently, the lifetime of a typical orthopaedic implant is only 15-20 years, a lifetime that many patients are outliving. Therefore, implants with superior longevity need to be engineered. To improve implant longevity, much research has been focused on creating micro-scale porosity/roughness to enhance osseointegration by mechanical interlocking of bone and implant. These structures have improved osseointegration to the current 15-20 year lifespan. It has also been shown that nano-scale structures enhance osteoblast (bone cell) function. The combination of micro-scale and nano-scale structures into one hierarchical structure may further improve the osseointegrative properties of implants. A hierarchical surface modification consisting of titanium dioxide [(TiO2)] nanotubes produced by anodic oxidation of titanium in an electrolyte containing fluoride ions, [F], on a commercially pure (cp) titanium, micro-scale grid structure produced by laser powder deposition was successfully developed. [TiO2] nanotubes were characterized using field emission scanning electron microscopy (FE-SEM), while laser deposited grid structures were characterized with both FE-SEM and optical microscopy. Mouse preosteoblasts were used to evaluate the in vitro biological effects, including cell morphology and cell viability, on the four experimental groups: unanodized flat, anodized flat, unanodized laser deposition, and anodized laser deposition. All treatment groups showed good cell attachment and spreading; however, it was observed that on the samples with [TiO2] nanotubes there was a much greater density of adhesion proteins. The presence of these proteins provides a surface that cells can more readily attach to which can lead to greater cell proliferation and differentiation. Also, viability of cells on samples with nanotubes was higher than samples without nanotubes. However, viability was highest on the anodized flat surface, suggesting that the micro-scale grid on the surface of laser deposition samples did not positively affect the osteoblasts. Optimization of the micro-scale surface features, along with anodization of the micro-scale structures, could possibly further improve the bone/implant interaction and further study is needed on this topic.
