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Hyung-min Shim - One of the best experts on this subject based on the ideXlab platform.
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Properties of titanium–silver alloys for Dental Application
Journal of Biomedical Materials Research Part B, 2005Co-Authors: Keun-taek Oh, Hyung-min ShimAbstract:The purpose of this study was to develop titanium–silver alloys with biocompatibility, high corrosion resistance, and low ion-release rate, and to evaluate the electrochemical properties of titanium–silver alloys in artificial saliva. Titanium–silver alloys with silver contents ranging from 0 to 4.5 at % in steps of 0.5 at % were designed. The alloys were arc melted, homogenized at 950°C for 72 h, hot rolled to 2 mm in thickness, and finally solution heat treated at 950°C for 1 h and quenched in water. Chemical compositions, phases, hardnesses, electrochemical properties, and the cytotoxicity of the alloys were investigated. The purity of titanium–silver alloys was maintained above 99.9%, because few impurities were introduced through their manufacture. In the case of alloys containing silver in the range 2.0–4.0 at %, the formation of an acicular α phase was observed inside the β phase. The acicular phase got thinner with increasing amounts of silver. This means that silver is a β-phase stabilizing element in titanium–silver alloys. The hardness value tended to rise with increasing silver content and increased largely over 3.5 at %, and the increase of the hardness value versus pure titanium was about 33%. It is believed that the substantial increases in hardness was due to the effects of solid solution strengthening and of α–β phase transition. Moreover, titanium–silver alloys had higher corrosion resistances than pure titanium. These results mean that silver additions to titanium can improve alloy corrosion resistance. Passive current densities in the potentiodynamic polarization curves were dependent on the chemical compositions of the titanium–silver alloys. However, they did not show a linear relationship with respect to silver contents. Titanium–silver alloys did not show pitting corrosion in artificial saliva. It is believed that silver addition to titanium strengthened the passive film due to titanium dissolution induced by the different electromotive forces of titanium and silver. In the agar overlay test, the cytotoxicity of the titanium–silver alloys and of titanium were none or mild. In summary, titanium–silver alloys had higher mechanical properties and corrosion resistance than titanium, and toxicities that were similar to titanium. Therefore, it is recommended that titanium–silver alloys be adopted cautiously by the biomedical and Dental fields. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater
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properties of titanium silver alloys for Dental Application
Journal of Biomedical Materials Research Part B, 2005Co-Authors: Keun-taek Oh, Hyung-min ShimAbstract:The purpose of this study was to develop titanium–silver alloys with biocompatibility, high corrosion resistance, and low ion-release rate, and to evaluate the electrochemical properties of titanium–silver alloys in artificial saliva. Titanium–silver alloys with silver contents ranging from 0 to 4.5 at % in steps of 0.5 at % were designed. The alloys were arc melted, homogenized at 950°C for 72 h, hot rolled to 2 mm in thickness, and finally solution heat treated at 950°C for 1 h and quenched in water. Chemical compositions, phases, hardnesses, electrochemical properties, and the cytotoxicity of the alloys were investigated. The purity of titanium–silver alloys was maintained above 99.9%, because few impurities were introduced through their manufacture. In the case of alloys containing silver in the range 2.0–4.0 at %, the formation of an acicular α phase was observed inside the β phase. The acicular phase got thinner with increasing amounts of silver. This means that silver is a β-phase stabilizing element in titanium–silver alloys. The hardness value tended to rise with increasing silver content and increased largely over 3.5 at %, and the increase of the hardness value versus pure titanium was about 33%. It is believed that the substantial increases in hardness was due to the effects of solid solution strengthening and of α–β phase transition. Moreover, titanium–silver alloys had higher corrosion resistances than pure titanium. These results mean that silver additions to titanium can improve alloy corrosion resistance. Passive current densities in the potentiodynamic polarization curves were dependent on the chemical compositions of the titanium–silver alloys. However, they did not show a linear relationship with respect to silver contents. Titanium–silver alloys did not show pitting corrosion in artificial saliva. It is believed that silver addition to titanium strengthened the passive film due to titanium dissolution induced by the different electromotive forces of titanium and silver. In the agar overlay test, the cytotoxicity of the titanium–silver alloys and of titanium were none or mild. In summary, titanium–silver alloys had higher mechanical properties and corrosion resistance than titanium, and toxicities that were similar to titanium. Therefore, it is recommended that titanium–silver alloys be adopted cautiously by the biomedical and Dental fields. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater
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properties of titanium silver alloys for Dental Application
Journal of Biomedical Materials Research, 2005Co-Authors: Keun-taek Oh, Hyung-min ShimAbstract:The purpose of this study was to develop titanium-silver alloys with biocompatibility, high corrosion resistance, and low ion-release rate, and to evaluate the electrochemical properties of titanium-silver alloys in artificial saliva. Titanium-silver alloys with silver contents ranging from 0 to 4.5 at % in steps of 0.5 at % were designed. The alloys were arc melted, homogenized at 950°C for 72 h, hot rolled to 2 mm in thickness, and finally solution heat treated at 950°C for 1 h and quenched in water. Chemical compositions, phases, hardnesses, electrochemical properties, and the cytotoxicity of the alloys were investigated. The purity of titanium-silver alloys was maintained above 99.9%, because few impurities were introduced through their manufacture. In the case of alloys containing silver in the range 2.0-4.0 at %, the formation of an acicular a phase was observed inside the β phase. The acicular phase got thinner with increasing amounts of silver. This means that silver is a β-phase stabilizing element in titanium-silver alloys. The hardness value tended to rise with increasing silver content and increased largely over 3.5 at %, and the increase of the hardness value versus pure titanium was about 33%. It is believed that the substantial increases in hardness was due to the effects of solid solution strengthening and of α-β phase transition. Moreover, titanium-silver alloys had higher corrosion resistances than pure titanium. These results mean that silver additions to titanium can improve alloy corrosion resistance. Passive current densities in the potentiodynamic polarization curves were dependent on the chemical compositions of the titanium-silver alloys. However, they did not show a linear relationship with respect to silver contents. Titanium-silver alloys did not show pitting corrosion in artificial saliva. It is believed that silver addition to titanium strengthened the passive film due to titanium dissolution induced by the different electromotive forces of titanium and silver. In the agar overlay test, the cytotoxicity of the titanium-silver alloys and of titanium were none or mild. In summary, titanium-silver alloys had higher mechanical properties and corrosion resistance than titanium, and toxicities that were similar to titanium. Therefore, it is recommended that titanium-silver alloys be adopted cautiously by the biomedical and Dental fields.
Keun-taek Oh - One of the best experts on this subject based on the ideXlab platform.
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effect of silver addition on the properties of nickel titanium alloys for Dental Application
Journal of Biomedical Materials Research Part B, 2006Co-Authors: Keun-taek Oh, Geeho Park, Chungju HwangAbstract:Equiatomic and near-equiatomic nickel–titanium alloys exhibit a shape-memory effect and superelasticity. However, the properties of such alloys are extremely sensitive to the precise nickel–titanium ratio and the addition of alloying elements. High corrosion resistance is necessary for biomedical Applications, especially orthodontic. The purpose of this study was to investigate the effect of silver addition to nickel–titanium alloys for Dental and medical Application. Arc melting, homogenization, hot rolling, and solution heat treatment were performed to prepare the nickel–titanium–silver (NiTi-Ag) specimens. The properties of the ternary NiTi–Ag alloys such as phase-transformation temperature, microstructure, microhardness, corrosion resistance, and cytotoxicity were investigated. The NiTi-Ag alloys showed low silver recovery rate for the cast alloy, due to silver's low evaporation temperature, and low silver solubility in nickel–titanium. Silver addition to nickel–titanium increased the transition temperature range to 100°C and stabilized the martensitic phase (monoclinic structure) at room temperature, because the martensitic transformation starting temperature (Ms) was above room temperature. Martensitic and austenitic phases existed in X-ray diffraction patterns of solution-annealed NiTi-Ag alloys. The silver addition was considered to improve the corrosion resistance and form a stable passive film. Significantly, the mechanical properties of the silver-added alloys were dependent upon the amount of alloying addition. There was no toxicity in the NiTi-Ag alloys, as the response index showed none or mild levels. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
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Properties of titanium–silver alloys for Dental Application
Journal of Biomedical Materials Research Part B, 2005Co-Authors: Keun-taek Oh, Hyung-min ShimAbstract:The purpose of this study was to develop titanium–silver alloys with biocompatibility, high corrosion resistance, and low ion-release rate, and to evaluate the electrochemical properties of titanium–silver alloys in artificial saliva. Titanium–silver alloys with silver contents ranging from 0 to 4.5 at % in steps of 0.5 at % were designed. The alloys were arc melted, homogenized at 950°C for 72 h, hot rolled to 2 mm in thickness, and finally solution heat treated at 950°C for 1 h and quenched in water. Chemical compositions, phases, hardnesses, electrochemical properties, and the cytotoxicity of the alloys were investigated. The purity of titanium–silver alloys was maintained above 99.9%, because few impurities were introduced through their manufacture. In the case of alloys containing silver in the range 2.0–4.0 at %, the formation of an acicular α phase was observed inside the β phase. The acicular phase got thinner with increasing amounts of silver. This means that silver is a β-phase stabilizing element in titanium–silver alloys. The hardness value tended to rise with increasing silver content and increased largely over 3.5 at %, and the increase of the hardness value versus pure titanium was about 33%. It is believed that the substantial increases in hardness was due to the effects of solid solution strengthening and of α–β phase transition. Moreover, titanium–silver alloys had higher corrosion resistances than pure titanium. These results mean that silver additions to titanium can improve alloy corrosion resistance. Passive current densities in the potentiodynamic polarization curves were dependent on the chemical compositions of the titanium–silver alloys. However, they did not show a linear relationship with respect to silver contents. Titanium–silver alloys did not show pitting corrosion in artificial saliva. It is believed that silver addition to titanium strengthened the passive film due to titanium dissolution induced by the different electromotive forces of titanium and silver. In the agar overlay test, the cytotoxicity of the titanium–silver alloys and of titanium were none or mild. In summary, titanium–silver alloys had higher mechanical properties and corrosion resistance than titanium, and toxicities that were similar to titanium. Therefore, it is recommended that titanium–silver alloys be adopted cautiously by the biomedical and Dental fields. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater
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properties of titanium silver alloys for Dental Application
Journal of Biomedical Materials Research Part B, 2005Co-Authors: Keun-taek Oh, Hyung-min ShimAbstract:The purpose of this study was to develop titanium–silver alloys with biocompatibility, high corrosion resistance, and low ion-release rate, and to evaluate the electrochemical properties of titanium–silver alloys in artificial saliva. Titanium–silver alloys with silver contents ranging from 0 to 4.5 at % in steps of 0.5 at % were designed. The alloys were arc melted, homogenized at 950°C for 72 h, hot rolled to 2 mm in thickness, and finally solution heat treated at 950°C for 1 h and quenched in water. Chemical compositions, phases, hardnesses, electrochemical properties, and the cytotoxicity of the alloys were investigated. The purity of titanium–silver alloys was maintained above 99.9%, because few impurities were introduced through their manufacture. In the case of alloys containing silver in the range 2.0–4.0 at %, the formation of an acicular α phase was observed inside the β phase. The acicular phase got thinner with increasing amounts of silver. This means that silver is a β-phase stabilizing element in titanium–silver alloys. The hardness value tended to rise with increasing silver content and increased largely over 3.5 at %, and the increase of the hardness value versus pure titanium was about 33%. It is believed that the substantial increases in hardness was due to the effects of solid solution strengthening and of α–β phase transition. Moreover, titanium–silver alloys had higher corrosion resistances than pure titanium. These results mean that silver additions to titanium can improve alloy corrosion resistance. Passive current densities in the potentiodynamic polarization curves were dependent on the chemical compositions of the titanium–silver alloys. However, they did not show a linear relationship with respect to silver contents. Titanium–silver alloys did not show pitting corrosion in artificial saliva. It is believed that silver addition to titanium strengthened the passive film due to titanium dissolution induced by the different electromotive forces of titanium and silver. In the agar overlay test, the cytotoxicity of the titanium–silver alloys and of titanium were none or mild. In summary, titanium–silver alloys had higher mechanical properties and corrosion resistance than titanium, and toxicities that were similar to titanium. Therefore, it is recommended that titanium–silver alloys be adopted cautiously by the biomedical and Dental fields. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater
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properties of titanium silver alloys for Dental Application
Journal of Biomedical Materials Research, 2005Co-Authors: Keun-taek Oh, Hyung-min ShimAbstract:The purpose of this study was to develop titanium-silver alloys with biocompatibility, high corrosion resistance, and low ion-release rate, and to evaluate the electrochemical properties of titanium-silver alloys in artificial saliva. Titanium-silver alloys with silver contents ranging from 0 to 4.5 at % in steps of 0.5 at % were designed. The alloys were arc melted, homogenized at 950°C for 72 h, hot rolled to 2 mm in thickness, and finally solution heat treated at 950°C for 1 h and quenched in water. Chemical compositions, phases, hardnesses, electrochemical properties, and the cytotoxicity of the alloys were investigated. The purity of titanium-silver alloys was maintained above 99.9%, because few impurities were introduced through their manufacture. In the case of alloys containing silver in the range 2.0-4.0 at %, the formation of an acicular a phase was observed inside the β phase. The acicular phase got thinner with increasing amounts of silver. This means that silver is a β-phase stabilizing element in titanium-silver alloys. The hardness value tended to rise with increasing silver content and increased largely over 3.5 at %, and the increase of the hardness value versus pure titanium was about 33%. It is believed that the substantial increases in hardness was due to the effects of solid solution strengthening and of α-β phase transition. Moreover, titanium-silver alloys had higher corrosion resistances than pure titanium. These results mean that silver additions to titanium can improve alloy corrosion resistance. Passive current densities in the potentiodynamic polarization curves were dependent on the chemical compositions of the titanium-silver alloys. However, they did not show a linear relationship with respect to silver contents. Titanium-silver alloys did not show pitting corrosion in artificial saliva. It is believed that silver addition to titanium strengthened the passive film due to titanium dissolution induced by the different electromotive forces of titanium and silver. In the agar overlay test, the cytotoxicity of the titanium-silver alloys and of titanium were none or mild. In summary, titanium-silver alloys had higher mechanical properties and corrosion resistance than titanium, and toxicities that were similar to titanium. Therefore, it is recommended that titanium-silver alloys be adopted cautiously by the biomedical and Dental fields.
Ke Yang - One of the best experts on this subject based on the ideXlab platform.
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preliminary study of microstructure mechanical properties and corrosion resistance of antibacterial ti 15zr xcu alloy for Dental Application
Journal of Materials Science & Technology, 2020Co-Authors: Sharafadeen Kunle Kolawole, Shuyuan Zhang, Muhammad Ali Siddiqui, Ihsan Ullah, Wei Song, Frank Witte, Ke YangAbstract:Abstract Ti-15Zr-xCu (3 ≤ x ≤ 7, wt.%) novel antibacterial and antibiofilm alloys with competitive mechanical properties, biological responses and corrosion resistance were designed and fabricated. Annealing heat treatment on Ti-15Zr-7Cu (TZC-7A), after holding for 2 h at slightly above their beta transus temperature (BTT) ensured their tensile strength (UTS), yield strength (YS) and hardness (HRV) were improved by 31.2%, 20% and 12.3% respectively compared to the control without Cu, Ti-15Zr (T-15ZA). Although the 3 wt.% Cu alloy displayed the highest elongation (26%), the TZC-7A alloy also possessed a good ductility. Presence of evenly dispersed Ti2Cu and Zr2Cu Cu-rich intermetallic phases formed as interwoven and alternating lamellae within the α + β matrix as a result of Cu addition, as revealed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). These greatly contributed to their strengthening and bactericidal properties. Over 98% antibacterial effect against E. coli and S. aureus have been imparted, coupled with excellent biofilm inhibition. Potentiodynamic polarization curves showed that the TZC-7A alloy possessed higher corrosion resistance than commercially pure titanium, cp-Ti; contact angle test revealed enhanced hydrophilicity; while confocal laser scanning microscopy (CLSM) and cell counting kit (CCK-8) assays also displayed drastically lowered bacterial adhesion rate with comparatively no cytotoxicity. Cell attachment on all alloys was similar but the best spread was obtained on TZC-7A after 24 h. The developed alloy has good potential as an antibacterial implant material with combination of optimized properties.
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in vitro and in vivo studies of anti bacterial copper bearing titanium alloy for Dental Application
Dental Materials, 2018Co-Authors: Yulong Tang, Lilan Zeng, Ying Zhao, Liangbi Xiang, Ke YangAbstract:Abstract Objective A novel copper-bearing titanium alloy (Ti–Cu) was fabricated for Dental Application that is expected to efficiently restrain the growth of bacteria and discourage biofilm formation. The aim of this study was to investigate both the antibacterial activity and biofilm inhibition of Ti–Cu alloy in vitro, and the antibacterial effect of Ti–Cu implant in early stage of peri-implantitis in vivo. Methods Staphylococcus aureus and Escherichia coli were selected to evaluate the antibacterial activity of Ti–Cu alloy and Ti served as control. The antibacterial rate, attached bacteria and developed biofilms were studied from quantitative antibacterial test, biofilm observation and bacterial morphological examination. Electrochemical tests were used to investigate the corrosion property of Ti–Cu alloy. Furthermore, both Ti and Ti–Cu Dental implants were manufactured and then implanted in the mandibular premolar sites of beagle dogs for 3 months with ligature-infected treatment. Implant-tissue samples were prepared for radiographic analysis, Micro-CT evaluation and histological examination. Results Ti–Cu alloy was found to efficiently kill the attached bacteria by ways of damaging cell membranes and cell walls and strongly inhibit the biofilm formation. However, Ti–Cu alloy had excellent corrosion resistance similar with Ti. Further, Ti–Cu Dental implants showed superior capacities of inhibiting the bone resorption caused by bacterial infection and enhancing bone formation. Significance Ti–Cu alloy strongly inhibited biofilm formation in vitro and prevented bacterial infection associated with Dental implant in vivo, making it great potential for Application in Dental implants with excellent antibacterial viability and positive effect against bone resorption induced by peri-implantitis.
Valter Sergo - One of the best experts on this subject based on the ideXlab platform.
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low temperature degradation aging of zirconia a critical review of the relevant aspects in dentistry
Dental Materials, 2010Co-Authors: Vanni Lughi, Valter SergoAbstract:Abstract This review presents a critical survey of all experimental data about the low temperature degradation of zirconia (often referred to as “aging”) due to the tetragonal-to-monoclinic transformation, which have been collected at temperatures of interest for Dental Application (room temperature to about 100 °C). It is shown that the main factors affecting the aging phenomenon are (i) the stabilizer type and content, (ii) the residual stress and (iii) the grain size. It is also shown that extrapolating the low temperature degradation rate from accelerated aging tests can lead to unacceptable conclusions about the lifetime of the zirconia-based components. Finally, based on the experimental evidence, a set of engineering guidelines for the use of zirconia in restorative and prosthetic dentistry is proposed.
Kenzo Asaoka - One of the best experts on this subject based on the ideXlab platform.
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in vivo setting behaviour of fast setting calcium phosphate cement
Biomaterials, 1995Co-Authors: Youji Miyamoto, Hirokazu Fukao, Masahiro Sawada, Masaru Nagayama, Kunio Ishikawa, Kenzo AsaokaAbstract:Abstract The in vivo setting behaviour of fast-setting calcium phosphate cement (FSCPC) between femoral muscles of the rat was investigated to evaluate the possible value of FSCPC for medical and Dental Application. Conventional CPC (c-CPC) and FSCPC were implanted between femoral muscles, and various aspects of the setting behaviour such as setting time, mechanical strength and conversion ratio of cement into hydroxyapatite (HAP: Ca 10 (PO 4 ) 6 (OH) 2 ) were measured by the Vicat needle method, diametral tensile strength (DTS) measurement, and quantitative powder X-ray diffraction (XRD) analysis, respectively. The setting time of FSCPC in vivo was 5–7 min, in contrast to 48 min for c-CPC. As a result of its fast setting, set specimens of FSCPC showed higher mechanical strength from the initial stage than c-CPC. Higher DTS values were observed in FSCPC than c-CPC implanted after 24 h. Powder XRD analysis revealed faster conversion of FSCPC than c-CPC into HAP, which was responsible both for the faster setting and higher mechanical strength from the initial stage. We concluded, therefore, that FSCPC may be used for a wide range of clinical Applications, i.e. fields where fast setting is required such as orthopaedic, plastic and reconstructive, and oral and maxillo-facial surgery.