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Takashi Nakamura - One of the best experts on this subject based on the ideXlab platform.
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development of a novel calcium phosphate cement composed mainly of calcium sodium phosphate with high Osteoconductivity
Journal of Materials Science: Materials in Medicine, 2014Co-Authors: Masashi Tanaka, Takashi Nakamura, Toshiyuki Kawai, Shunsuke Fujibayashi, Mitsuru Takemoto, Masako Tsukanaka, Kimiaki Takami, Satoshi Motojima, Hikaru Inoue, Shuichi MatsudaAbstract:Two novel calcium phosphate cements (CPC) have been developed using calcium sodium phosphate (CSP) as the main ingredient. The first of these cements, labeled CAC, contained CSP, α-tricalcium phosphate (TCP), and anhydrous citric acid, whereas the second, labeled CABC, contained CSP, α-TCP, β-TCP, and anhydrous citric acid. Biopex®-R (PENTAX, Tokyo, Japan), which is a commercially available CPC (Com-CPC), and OSferion® (Olympus Terumo Biomaterials Corp., Tokyo, Japan), which is a commercially available porous β-TCP, were used as reference controls for analysis. In vitro analysis showed that CABC set in 5.7 ± 0.3 min at 22 °C and had a compressive strength of 86.0 ± 9.7 MPa after 5 days. Furthermore, this material had a compressive strength of 26.7 ± 3.7 MPa after 2 h in physiologic saline. CAC showed a statistically significantly lower compressive strength in the presence of physiologic saline and statistically significantly longer setting times than those of CABC. CABC and CAC exhibited apatite-forming abilities in simulated body fluid that were faster than that of Com-CPC. Samples of the materials were implanted into the femoral condyles of rabbits for in vivo analysis, and subsequent histological examinations revealed that CABC exhibited superior Osteoconductivity and equivalent bioresorbability compared with Com-CPC, as well as superior Osteoconductivity and bioresorbability compared with CAC. CABC could therefore be used as an alternative bone substitute material.
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enhanced Osteoconductivity of positively charged titanium metal
Key Engineering Materials, 2011Co-Authors: Toshiyuki Kawai, Tadashi Kokubo, Masashi Neo, Shunsuke Fujibayashi, Mitsuru Takemoto, Deepak K Pattanayak, Kenji Doi, Tomiharu Matsushita, Takashi NakamuraAbstract:We previously found that a positively charged Ti metal has a higher apatite forming ability in vitro than a non-charged Ti metal. For in vivo analysis using a rabbit model, two types of Ti metal were examined: porous Ti metals heat-treated subsequent to a mixed acid treatment (MHs) and porous Ti metals not heat-treated subsequent to the same mixed acid treatment (MOs). Although MHs and MOs had the same macro- and micro-structure, they had different surface charges. MHs, considered positively charged, had significantly higher bone ingrowth than MOs, considered charged zero. Similarly, MHs had significantly higher percentages of bone–implant contact than MOs at 3- and 6-week. A simple heat treatment made acid-treated porous titanium implants more osteoconductive. These results suggest that a positive charge obtained by a heat treatment enhances bioactivity of acid-treated titanium implants.
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bioactive bone cement with a low content of titania particles without postsilanization effect of filler content on Osteoconductivity mechanical properties and handling characteristics
Journal of Biomedical Materials Research Part B, 2010Co-Authors: Chisako Fukuda, Koji Goto, Masashi Imamura, Takashi NakamuraAbstract:In this study, we developed three types of polymethylmethacrylate (PMMA)-based composite cement with low contents of nonsilanized titania particles (5, 10, and 20 wt % TiO2, respectively: designated T5, T10, and T20). The Osteoconductivity, mechanical properties, and handling characteristics of these cements were compared with those of commercially available PMMA cement (PMMAc). The cement was inserted into rat tibiae and solidified in situ. After 6 and 12 weeks, tibiae were removed for evaluation of Osteoconductivity using Stevenel's Blue and Van Gieson's picrofuchsin staining. The affinity indices reflecting the Osteoconductivity of T10 and T20 were 33.4 ± 12.8 and 56.5 ± 14.1 at 6 weeks, and 67.0 ± 18.0 and 65.0 ± 51.7 at 12 weeks, respectively, and were significantly higher than for PMMAc (p < 0.01). The compressive and flexural strengths of T5, T10, and T20 exceeded those of PMMAc, whereas the elasticity did not differ significantly. Scanning electron microscopy and energy-dispersive X-ray microanalysis showed that the micron-sized and spherical titania particles were well dispersed in T20 and were exposed on the surface of the cement that made direct contact with bone. These results show that T20 is a promising bioactive bone cement for use in prosthesis fixation. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010.
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Long-Term Study of Osteoconductivity of Bioactive Porous Titanium Metals: Effect of Sodium Removal by Dilute HCl Treatment
Key Engineering Materials, 2008Co-Authors: Kojiro Tanaka, Tadashi Kokubo, Keiichi Kawanabe, Shunsuke Fujibayashi, Mitsuru Takemoto, Tomiharu Matsushita, Takashi NakamuraAbstract:In a previous study, we have reported that sodium removal by dilute hydrochloric acid (HCl) converted the sodium titanate layer on the surface of an alkali-treated porous titanium into titania with a specific structure that has better bioactivity than sodium titanate. We have shown that a porous titanium with this treatment have good osteoinductivity in soft tissue of canines. In the present study, we investigated the effect of this treatment on the osteoconductive abilities of porous bioactive titanium implant in the long term. Three types of surface treatments were applied: (a) no treatment , (b) alkali, hot water, and heat treatment ( conventional treatment: W-AH treatment), and (c) alkali, dilute HCl, hot water, and heat treatment (Na-free treatment: HCl-AH treatment). We then examined the Osteoconductivity of the materials implanted in the femoral condyles of Japanese white rabbits at 6, 12, 26, and 52 weeks. The results showed that the bone ingrowth in HCl-AH porous bioactive titanium was significantly higher than in W-AH porous bioactive titanium at 52 weeks. Therefore, sodium removal has a positive effect on the Osteoconductivity of the porous bioactive titanium implant in the long term.
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the biocompatibility and Osteoconductivity of a cement containing β tcp for use in vertebroplasty
Journal of Biomedical Materials Research Part A, 2006Co-Authors: Koji Goto, Shuichi Shinzato, Keiichi Kawanabe, Jiro Tamura, Shunsuke Fujibayashi, Shin Hasegawa, R. Kowalski, Takashi NakamuraAbstract:A new composite bone cement designated “G2B1” was developed for percutaneous transpedicular vertebroplasty. G2B1 contains beta tricalcium phosphate particles and methylmethacrylate–methylacrylate copolymer as the powder components, and methylmethacrylate, urethane dimethacrylate, and tetrahydrofurfuryl methacrylate as the liquid components. Biocompatibility and Osteoconductivity were evaluated using scanning electron microscopy, contact microradiography, and Giemsa surface staining 4, 8, 12, 26, and 52 weeks after implantation into rat tibiae. To evaluate Osteoconductivity, affinity indices (%) were calculated. Scanning electron microscopy and contact microradiography revealed that bone contact with G2B1 was attained within 4 weeks (affinity index: 50.2 ± 11.8 at 4 weeks) and at most of the margin within 26 weeks (affinity index: 87.4 ± 7.2 at 26 weeks). Specifically, G2B1 contacted bone via a wide calcium–phosphate-rich layer, and its degradation started within 8 weeks, mainly in the marginal area. Giemsa surface staining showed that there was almost no inflammatory reaction around the G2B1. These results indicate that G2B1 is a biocompatible and osteoconductive bone cement. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Masazumi Okido - One of the best experts on this subject based on the ideXlab platform.
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Surface Modification of PEEK and Its Osteoconductivity and Anti-Inflammatory Properties
Journal of Biomaterials and Nanobiotechnology, 2018Co-Authors: Kensuke Kuroda, Hiroyasu Kanetaka, Kenta Igarashi, Masazumi OkidoAbstract:Polyetheretherketone (PEEK) is known as one of the “super-engineering plastics” and is used as an intervertebral disk spacer in the body. PEEK has a hydrophobic surface (water contact angle (WCA) > 80°) and high chemical resistance, and it is thus difficult to perform any surface treatment, such as hydrophilization. In this study, we aimed to form a hydrophilic surface on PEEK without coating layers by using hydroprocessing (aqueous solution processing), and we examined the Osteoconductivity and anti-inflammatory properties of surface-treated PEEK in vivo compared with Ti implants. The WCA value of PEEK reached ~20° using a combination of immersion in a solution of >16.2 M H2SO4 and ultraviolet irradiation (172 nm). In in vivo testing, the hydrophilization of PEEK by surface modification without a coating layer improved the Osteoconductivity and anti-inflammatory properties. The relationship between the bone-implant contact ratio and the WCA values of the surface-modified PEEK agreed well with that of the surface-treated Ti.
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Osteoconductivity Control Based on the Chemical Properties of the Implant Surface
Journal of Biomaterials and Nanobiotechnology, 2017Co-Authors: Kensuke Kuroda, Masazumi OkidoAbstract:Metallic materials, such as Ti, Zr, Nb, Ta, and their alloys, and also stainless steels are widely attractive as osteoconductive materials in the dental and orthopedic fields. Ceramics and polymers are also commonly used as biomaterials. However, they do not have high Osteoconductivity in their pure form, and surface coatings with bioactive substances, such as hydroxyapatite or TiO2, are needed before implantation into the bone. Many reports claim that the surface chemical properties of implants, in particular, hydrophilicity and hydrophobicity, strongly affect the biological reactions. However, the effect of surface properties on Osteoconductivity is not clear. In this review, we focus on the relationship between the surface hydrophilicity of metallic implants and Osteoconductivity using in vivo evaluation, and the control of the Osteoconductivity is discussed from the viewpoint of protein adsorption in implants.
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High Osteoconductive Surface of Pure Titanium by Hydrothermal Treatment
2016Co-Authors: Mansjur Zuldesmi, Kensuke Kuroda, Atsushi Waki, Masazumi OkidoAbstract:Copyright © 2013 Mansjur Zuldesmi et al. This is an open access article distributed under the Creative Commons Attribution Li-cense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Surface properties of Ti implants (especially surface hydrophilicity) influence biological responses at the interface be-tween the bone tissue and the implant. However, only a little research reported the effect of surface hydrophilicity on Osteoconductivity by in vivo test. We have investigated the surface characteristics and Osteoconductivity of titanium implant produced by hydrothermal treatment using distilled water at temperature of 180˚C for 3 h, and compared with as-polished and those of implants produced by anodizing in 0.1 M H2SO4 with applied voltage from 0 V to 100 V at 0.1 Vs−1 and anodizing followed by hydrothermal treatment. The relationship between hydrophilic surface and osteocon-ductivity in various surface modifications was examined by in vivo test. In order to maintain the hydrophilicity of the hydrothermal sample surface, it was kept in to the phosphate buffered saline solution (PBS) with 5 times concentration: 5PBS(−) in room temperature. The surface characteristics were evaluated by scanning electron microscopy, XRD, X-ray photoelectron spectroscopy, surface roughness and contact angle measurement using a 2 µL droplet of distilled water. In in vivo testing, the rod samples (ɸ2 × 5 mm) were implanted in male rat’s tibiae for 14 days and the bone-im-plant contact ratio, RB-I, was used to evaluate the Osteoconductivity in the cortical and cancellous bone parts, respec
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Osteoconductivity of Superhydrophilic Ti- and Zr-Alloy for Biomedical Application
Materials Science Forum, 2016Co-Authors: Masazumi Okido, Kensuke KurodaAbstract:Surface hydrophilicity is considered to have a strong influence on the biological reactions of bone-substituting materials. However, the influence of a hydrophilic or hydrophobic surface on the Osteoconductivity is not completely clear. In this study, we produced super-hydrophilic and hydrophobic surface on Ti-and Zr-alloys. Hydrothermal treatment at 180 oC for 180 min. in the distilled water and immersion in x5 PBS(-) brought the super-hydrophilic surface (water contact angle < 10 (deg.)) and heat treatment of as-hydrothermaled the hydrophobic surface. The Osteoconductivity of the surface treated samples with several water contact angle was evaluated by in vivo testing. The surface properties, especially water contact angle, strongly affected the Osteoconductivity and protein adsorbability, and not the surface substance.
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Osteoconductivity of Protein Adsorbed Titanium Implants Using Hydrothermal Treatment
Materials Science Forum, 2016Co-Authors: Kensuke Kuroda, Masazumi OkidoAbstract:Protein adsorption is considered to have a strong influence on the biological reactions of bone-substituting materials. However, the Osteoconductivity of protein adsorbed Ti surface is not completely clear. In this study, we produced the protein adsorbed Ti implants using hydro-processing. The hydrothermal treatment in the distilled water gave the super-hydrophilic Ti surface and they had much protein adsorbability. Fibronectin or albumin was picked up as a protein, which was cell adhesive protein and not cell adhesive, respectively. And also, the content of the adsorbed protein was evaluated by FT-IR (ATR) analysis. The water contact angle influenced the amount of the adsorption of the protein and the Osteoconductivity of the samples were evaluated by in vivo testing.
Kensuke Kuroda - One of the best experts on this subject based on the ideXlab platform.
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Effects of Titanium Surface Wettability on Osteoblast Behavior In Vitro
Materials Science Forum, 2020Co-Authors: Kenta Nisogi, Satoshi Okano, Sengo Kobayashi, Kensuke Kuroda, Takeaki OkamotoAbstract:Surface wettability is thought to influence the Osteoconductivity of bone-substituting materials; however, the effects of surface wettability on osteoblast behavior are not well understood. In this study, we prepared both an as-polished pure titanium with a water contact angle (WCA) of 57° and heat-treated pure titanium with more hydrophobic surface and WCAs of 68°-98°. The effects of the surface wettability of pure titanium on osteoblast behaviors were evaluated by in vitro assays. Compared with the as-polished titanium, the proliferation rate of osteoblast increased on heat-treated titanium. This suggested that surface wettability affects osteoblast behaviors, meaning Osteoconductivity is influenced by surface wettability.
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Surface Modification of PEEK and Its Osteoconductivity and Anti-Inflammatory Properties
Journal of Biomaterials and Nanobiotechnology, 2018Co-Authors: Kensuke Kuroda, Hiroyasu Kanetaka, Kenta Igarashi, Masazumi OkidoAbstract:Polyetheretherketone (PEEK) is known as one of the “super-engineering plastics” and is used as an intervertebral disk spacer in the body. PEEK has a hydrophobic surface (water contact angle (WCA) > 80°) and high chemical resistance, and it is thus difficult to perform any surface treatment, such as hydrophilization. In this study, we aimed to form a hydrophilic surface on PEEK without coating layers by using hydroprocessing (aqueous solution processing), and we examined the Osteoconductivity and anti-inflammatory properties of surface-treated PEEK in vivo compared with Ti implants. The WCA value of PEEK reached ~20° using a combination of immersion in a solution of >16.2 M H2SO4 and ultraviolet irradiation (172 nm). In in vivo testing, the hydrophilization of PEEK by surface modification without a coating layer improved the Osteoconductivity and anti-inflammatory properties. The relationship between the bone-implant contact ratio and the WCA values of the surface-modified PEEK agreed well with that of the surface-treated Ti.
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Osteoconductivity Control Based on the Chemical Properties of the Implant Surface
Journal of Biomaterials and Nanobiotechnology, 2017Co-Authors: Kensuke Kuroda, Masazumi OkidoAbstract:Metallic materials, such as Ti, Zr, Nb, Ta, and their alloys, and also stainless steels are widely attractive as osteoconductive materials in the dental and orthopedic fields. Ceramics and polymers are also commonly used as biomaterials. However, they do not have high Osteoconductivity in their pure form, and surface coatings with bioactive substances, such as hydroxyapatite or TiO2, are needed before implantation into the bone. Many reports claim that the surface chemical properties of implants, in particular, hydrophilicity and hydrophobicity, strongly affect the biological reactions. However, the effect of surface properties on Osteoconductivity is not clear. In this review, we focus on the relationship between the surface hydrophilicity of metallic implants and Osteoconductivity using in vivo evaluation, and the control of the Osteoconductivity is discussed from the viewpoint of protein adsorption in implants.
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High Osteoconductive Surface of Pure Titanium by Hydrothermal Treatment
2016Co-Authors: Mansjur Zuldesmi, Kensuke Kuroda, Atsushi Waki, Masazumi OkidoAbstract:Copyright © 2013 Mansjur Zuldesmi et al. This is an open access article distributed under the Creative Commons Attribution Li-cense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Surface properties of Ti implants (especially surface hydrophilicity) influence biological responses at the interface be-tween the bone tissue and the implant. However, only a little research reported the effect of surface hydrophilicity on Osteoconductivity by in vivo test. We have investigated the surface characteristics and Osteoconductivity of titanium implant produced by hydrothermal treatment using distilled water at temperature of 180˚C for 3 h, and compared with as-polished and those of implants produced by anodizing in 0.1 M H2SO4 with applied voltage from 0 V to 100 V at 0.1 Vs−1 and anodizing followed by hydrothermal treatment. The relationship between hydrophilic surface and osteocon-ductivity in various surface modifications was examined by in vivo test. In order to maintain the hydrophilicity of the hydrothermal sample surface, it was kept in to the phosphate buffered saline solution (PBS) with 5 times concentration: 5PBS(−) in room temperature. The surface characteristics were evaluated by scanning electron microscopy, XRD, X-ray photoelectron spectroscopy, surface roughness and contact angle measurement using a 2 µL droplet of distilled water. In in vivo testing, the rod samples (ɸ2 × 5 mm) were implanted in male rat’s tibiae for 14 days and the bone-im-plant contact ratio, RB-I, was used to evaluate the Osteoconductivity in the cortical and cancellous bone parts, respec
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Osteoconductivity of Superhydrophilic Ti- and Zr-Alloy for Biomedical Application
Materials Science Forum, 2016Co-Authors: Masazumi Okido, Kensuke KurodaAbstract:Surface hydrophilicity is considered to have a strong influence on the biological reactions of bone-substituting materials. However, the influence of a hydrophilic or hydrophobic surface on the Osteoconductivity is not completely clear. In this study, we produced super-hydrophilic and hydrophobic surface on Ti-and Zr-alloys. Hydrothermal treatment at 180 oC for 180 min. in the distilled water and immersion in x5 PBS(-) brought the super-hydrophilic surface (water contact angle < 10 (deg.)) and heat treatment of as-hydrothermaled the hydrophobic surface. The Osteoconductivity of the surface treated samples with several water contact angle was evaluated by in vivo testing. The surface properties, especially water contact angle, strongly affected the Osteoconductivity and protein adsorbability, and not the surface substance.
Hala Zreiqat - One of the best experts on this subject based on the ideXlab platform.
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beta tricalcium phosphate exerts Osteoconductivity through α2β1 integrin and down stream mapk erk signaling pathway
Biochemical and Biophysical Research Communications, 2010Co-Authors: Hala ZreiqatAbstract:Beta-tricalcium phosphate (β-TCP) has been clinically used as a bone graft substitute for decades because of its excellent Osteoconductivity. However, the exact mechanism(s) by which β-TCP exerts Osteoconductivity are not fully documented. This study was aimed to investigate the molecular mechanism(s) by which β-TCP modulates the biological response of primary human osteoblasts (HOBs). It was showed that HOBs seeded into the β-TCP scaffolds expressed significantly higher levels of osteogenic genes, compared to those cultured on tissue culture plastic; meanwhile these cells showed 7-fold increase in α2 integrin subunit gene expression and the activation of the mitogen-activated protein kinase (MAPK)/extracellular related kinase (ERK) signaling pathway. In addition, the osteogenic conduction by β-TCP scaffolds was attenuated directly by inhibiting MAPK/ERK or indirectly by blocking the α2β1 integrin signaling pathway. We concluded that β-TCP scaffold exerts Osteoconductivity through α2β1 integrin and down-stream MAPK/ERK signaling pathway, suggesting a feasible approach to consider when designing or fabricating the scaffolds for bone tissue engineering.
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Beta-tricalcium phosphate exerts Osteoconductivity through α2β1 integrin and down-stream MAPK/ERK signaling pathway
Biochemical and biophysical research communications, 2010Co-Authors: Hala ZreiqatAbstract:Beta-tricalcium phosphate (β-TCP) has been clinically used as a bone graft substitute for decades because of its excellent Osteoconductivity. However, the exact mechanism(s) by which β-TCP exerts Osteoconductivity are not fully documented. This study was aimed to investigate the molecular mechanism(s) by which β-TCP modulates the biological response of primary human osteoblasts (HOBs). It was showed that HOBs seeded into the β-TCP scaffolds expressed significantly higher levels of osteogenic genes, compared to those cultured on tissue culture plastic; meanwhile these cells showed 7-fold increase in α2 integrin subunit gene expression and the activation of the mitogen-activated protein kinase (MAPK)/extracellular related kinase (ERK) signaling pathway. In addition, the osteogenic conduction by β-TCP scaffolds was attenuated directly by inhibiting MAPK/ERK or indirectly by blocking the α2β1 integrin signaling pathway. We concluded that β-TCP scaffold exerts Osteoconductivity through α2β1 integrin and down-stream MAPK/ERK signaling pathway, suggesting a feasible approach to consider when designing or fabricating the scaffolds for bone tissue engineering.
Shuichi Shinzato - One of the best experts on this subject based on the ideXlab platform.
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The biocompatibility and Osteoconductivity of a cement containing β–TCP for use in vertebroplasty
Journal of biomedical materials research. Part A, 2006Co-Authors: Koji Goto, Shuichi Shinzato, Keiichi Kawanabe, Jiro Tamura, Shunsuke Fujibayashi, Shin Hasegawa, R. Kowalski, Takashi NakamuraAbstract:A new composite bone cement designated “G2B1” was developed for percutaneous transpedicular vertebroplasty. G2B1 contains beta tricalcium phosphate particles and methylmethacrylate–methylacrylate copolymer as the powder components, and methylmethacrylate, urethane dimethacrylate, and tetrahydrofurfuryl methacrylate as the liquid components. Biocompatibility and Osteoconductivity were evaluated using scanning electron microscopy, contact microradiography, and Giemsa surface staining 4, 8, 12, 26, and 52 weeks after implantation into rat tibiae. To evaluate Osteoconductivity, affinity indices (%) were calculated. Scanning electron microscopy and contact microradiography revealed that bone contact with G2B1 was attained within 4 weeks (affinity index: 50.2 ± 11.8 at 4 weeks) and at most of the margin within 26 weeks (affinity index: 87.4 ± 7.2 at 26 weeks). Specifically, G2B1 contacted bone via a wide calcium–phosphate-rich layer, and its degradation started within 8 weeks, mainly in the marginal area. Giemsa surface staining showed that there was almost no inflammatory reaction around the G2B1. These results indicate that G2B1 is a biocompatible and osteoconductive bone cement. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
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the biocompatibility and Osteoconductivity of a cement containing β tcp for use in vertebroplasty
Journal of Biomedical Materials Research Part A, 2006Co-Authors: Koji Goto, Shuichi Shinzato, Keiichi Kawanabe, Jiro Tamura, Shunsuke Fujibayashi, Shin Hasegawa, R. Kowalski, Takashi NakamuraAbstract:A new composite bone cement designated “G2B1” was developed for percutaneous transpedicular vertebroplasty. G2B1 contains beta tricalcium phosphate particles and methylmethacrylate–methylacrylate copolymer as the powder components, and methylmethacrylate, urethane dimethacrylate, and tetrahydrofurfuryl methacrylate as the liquid components. Biocompatibility and Osteoconductivity were evaluated using scanning electron microscopy, contact microradiography, and Giemsa surface staining 4, 8, 12, 26, and 52 weeks after implantation into rat tibiae. To evaluate Osteoconductivity, affinity indices (%) were calculated. Scanning electron microscopy and contact microradiography revealed that bone contact with G2B1 was attained within 4 weeks (affinity index: 50.2 ± 11.8 at 4 weeks) and at most of the margin within 26 weeks (affinity index: 87.4 ± 7.2 at 26 weeks). Specifically, G2B1 contacted bone via a wide calcium–phosphate-rich layer, and its degradation started within 8 weeks, mainly in the marginal area. Giemsa surface staining showed that there was almost no inflammatory reaction around the G2B1. These results indicate that G2B1 is a biocompatible and osteoconductive bone cement. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
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Alumina Powder Containing δ, γ Crystal Phases: Evaluation of Osteoconductivity
Key Engineering Materials, 2006Co-Authors: Shuichi Shinzato, Takashi Nakamura, Koji Goto, Tadashi KokuboAbstract:Alumina powder containing δ , δ crystal phases (designated δAP) showed Osteoconductivity. δAP was manufactured by fusing pulverized alumina powder and quenching it. The purpose of the present study was to evaluate Osteoconductivity of δAP using rat tibiae. Alumina powder containing αcrystal phase (designated αAP) was used as a reference material. These two types of alumina powder were packed into the intramedullary canals of rat tibiae to evaluate Osteoconductivity, as determined by an affinity index. Rats were sacrificed at 4 and 8 weeks after surgery. The affinity index, equal to the length of bone in direct contact with the powder surface expressed as a percentage of the total length of the powder surface, was calculated for each alumina powder at each interval. At 4 and 8 weeks, the affinity indices for δAP were significantly higher than those for αAP. For both δAP and αAP, there were no significant differences between the values for 4 and 8 weeks. This study revealed that the Osteoconductivity of δAP was due to the alumina’s δcrystal phases. δAP shows promise as a basis for developing a osteoconductive biomaterial.
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bioactive bone cements containing nano sized titania particles for use as bone substitutes
Biomaterials, 2005Co-Authors: Koji Goto, Shuichi Shinzato, Tadashi Kokubo, Masami Hashimoto, Masakazu Kawashita, Jiro Tamura, Shunsuke Fujibayashi, Takashi NakamuraAbstract:Three types of bioactive polymethylmethacrylate (PMMA)-based bone cement containing nano-sized titania (TiO2) particles were prepared, and their mechanical properties and Osteoconductivity are evaluated. The three types of bioactive bone cement were T50c, ST50c, and ST60c, which contained 50 wt% TiO2, and 50 and 60 wt% silanized TiO2, respectively. Commercially available PMMA cement (PMMAc) was used as a control. The cements were inserted into rat tibiae and allowed to solidify in situ. After 6 and 12 weeks, tibiae were removed for evaluation of Osteoconductivity using scanning electron microscopy (SEM), contact microradiography (CMR), and Giemsa surface staining. SEM revealed that ST60c and ST50c were directly apposed to bone while T50c and PMMAc were not. The osteoconduction of ST60c was significantly better than that of the other cements at each time interval, and the osteoconduction of T50c was no better than that of PMMAc. The compressive strength of ST60c was equivalent to that of PMMAc. These results show that ST60c is a promising material for use as a bone substitute.
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pmma based bioactive cement effect of glass bead filler content and histological change with time
Journal of Biomedical Materials Research, 2002Co-Authors: Shuichi Shinzato, Tadashi Kokubo, Takashi Nakamura, Yoshiro KitamuraAbstract:A new bioactive bone cement (designated GBC), which is a polymethyl methacrylate (PMMA)-based composite consisting of bioactive glass beads as an inorganic filler and high molecular-weight PMMA as an organic matrix, has been developed. The purpose of the present study was to evaluate the effect of the filler content on the mechanical properties and Osteoconductivity of GBC, to decide the most suitable filler proportion, and to evaluate the degree of cement degradation with time. The bioactive beads, consisting of MgO-CaO-SiO2-P2O5-CaF2 glass, were added to the cement in various proportions (40–70 wt %). The bending strength of GBC did not differ among the proportions (approximately 136 MPa), but the elastic modulus of bending of GBC increased as the glass bead filler content increased (approximately 4.1–7.2 GPa). The all types of GBC were packed into the intramedullary canals of rat tibiae to evaluate Osteoconductivity, as determined by an affinity index calculated as the length of bone in direct contact with the cement surface expressed as a percentage of the total length of the cement surface. Rats were sacrificed at 4, 8, 25, and 39 weeks after implantation, and the affinity index was calculated for each type of GBC at each time point. Histologically, new bone had formed along the surface of all types of GBC within 4 weeks, even in GBC containing only 40 wt % of glass beads. The affinity indices of GBC tended to increase as the proportion of glass bead filler increased and as the implantation period increased. In GBC containing 60 or 70 wt % of glass beads, significant rapid increases in the affinity indices were found from 4 to 8 weeks, and the high values (approximately 70%) were maintained up to 39 weeks. A sign of glass bead degradation was observed at the bone–cement interface in the rat tibiae at 39 weeks. We conclude that, when mechanical properties and Osteoconductivity are both taken into consideration, GBC containing 60 or 70 wt % of glass beads is the most suitable formulation, but that further studies are needed to investigate and overcome the degradation. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 225–232, 2002
