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Obata A.,Nagoya Institute of Technology | Wakita T.,Nagoya Institute of Technology | Wakita T.,Yamahachi Dental Manufacturing Co. | Ota Y.,Yabashi Industries Co. | Kasuga T.,Nagoya Institute of Technology
Materials Science Forum | Year: 2010

Microfiber meshes releasing a trace amount of silicon species were prepared by electrospinning silicon-doped vaterite (SiV) and poly(lactic acid) (PLA) hybrids for application to membranes for guided bone regeneration (GBR). A trace amount of silicon-species has been reported to enhance the mineralization and bone-forming abilities of osteogenic cells. The microfiber meshes prepared by electrospinning are regarded to be a useful candidate for the GBR membrane, because they have adequate flexibility and porosity for it. In this study, hydroxyapatite (HA)-forming abilities in simulated body fluid, silicon-releasabilities, compatibility with osteoblast-like cells of the prepared microfiber meshes were examined. The meshes were completely coated with HA after soaking in simulated body fluid for 1 day. The meshes coated with HA released 0.2 -0.7 mg/L of silicon species in a cell culture medium for 7 days. The cells elongated on the microfibers of the meshes and some of them entered the mesh after 1 day-culturing. The meshes are expected to provide an excellent substrate for bone regeneration and enhance bone-forming ability of the cells. © (2010) Trans Tech Publications.


Obata A.,Nagoya Institute of Technology | Hotta T.,Nagoya Institute of Technology | Wakita T.,Nagoya Institute of Technology | Wakita T.,Yamahachi Dental Manufacturing Co. | And 2 more authors.
Acta Biomaterialia | Year: 2010

Silicon-releasable microfiber meshes consisting of silicon-doped vaterite (SiV) particles and poly(lactic acid) (PLA) hybrids were prepared by electrospinning. Due to their flexibility and porosity they formed ideal membranes or scaffolds for guided bone regeneration. In addition, a trace amount of silicon species has been reported to stimulate osteogenic cells to mineralize and enhance bone formation. We propose a new method of preparation of silicon-releasing microfiber meshes by electrospinning. Their structure and hydroxyapatite (HA)-forming abilities in simulated body fluid were examined. In addition, we studied their stimulatory effects on osteoblast-like cells in vitro and bone-forming ability in vivo, with a special emphasis on their ability to release silicon. The meshes consisted of a hybrid of carboxy groups in PLA and amino groups in siloxane, derived from aminopropyltriethoxysilane or calcium ions on the SiV surface. This hybrid exhibited an enhanced ability to form HA. The meshes coated with HA released 0.2-0.7 mg l-1 silicon species into the culture medium over 7 days. Enhanced proliferation of osteoblast-like cells was observed using the meshes and new bone formed on the meshes when implanted into the calvaria of rabbits. These meshes, therefore, provide an excellent substrate for bone regeneration and exhibit enhanced bone-forming ability under both in vitro and in vivo conditions. © 2009 Acta Materialia Inc.


Tsutsumi H.,Tohoku University | Niinomi M.,Tohoku University | Akahori T.,Tohoku University | Nakai M.,Tohoku University | And 2 more authors.
Keikinzoku/Journal of Japan Institute of Light Metals | Year: 2010

The applicability of a calcia mold to casting a β-type titanium alloy, Ti-29Nb-13Ta-4.6Zr (TNTZ), was evaluated with focusing on the dimensional accuracy of the casting in this study. Pure zirconium particles were added to a calcia mold to take advantage of the expansion of oxidized zirconium during the baking process in order to compensate for the solidification shrinkage of TNTZ. The morphological characteristics of the casting surface, such as the roughness and dimensional accuracy, of the cast TNTZ were investigated. The dilation ratio of the calcia mold is found to increase with increasing the number of pure zirconium particles. The addition of 12 mass % or 14 mass % pure zirconium particles compensates for not only the solidification of TNTZ but also the occurrence of shrinkage of the calcia mold. In addition, the formation of a surface reaction layer in TNTZ is restrained to a larger extent by casting into a calcia mold than into a magnesia mold, which is the conventional investment mold for titanium casting. Furthermore, the volume fraction and number of casting defects are also restrained to a larger extent by casting into a calcia mold than into a magnesia mold. The results of this study should lead to enhancements in the creation of cast TNTZ for dental products.


Tsutsumi H.,Tohoku University | Niinomi M.,Tohoku University | Akahori T.,Tohoku University | Nakai M.,Tohoku University | And 2 more authors.
Keikinzoku/Journal of Japan Institute of Light Metals | Year: 2010

A calcia mold, which is stable at high temperatures for dental precision casting of β-type titanium alloys such as Ti-29mass%Nb-13mass%Ta-4.6mass%Zr alloy (TNTZ) with high melting point, has been developed. The applicability of the calcia mold to casting TNTZ was evaluated with focusing on the mechanical properties of the casting in this study. The molten TNTZ was cast into the calcia mold of which dimensional accuracy was controlled by adding pure zirconium particles. The tensile and fatigue properties of TNTZ cast into the calcia mold were examined with comparing those of TNTZ cast into the magnesia mold, which is the conventional one for casting titanium alloys. The tensile properties of TNTZ cast into the calcia and the magnesia molds are not markedly different The fatigue strength of TNTZ cast into the calcia mold in the low- and high-cycle fatigue life regions is slightly higher than that of TNTZ cast into the magnesia mold. Therefore, the calcia mold is expected to be applicable to the dental precision casting of TNTZ.


Patent
Nagoya Institute of Technology, YAMAHACHI DENTAL Manufacturing CO. and Yabashi Industries Co. | Date: 2012-08-22

A guided bone regeneration material is disclosed. The guided bone regeneration material includes biodegradable fibers produced by an electro spinning method. The biodegradable fibers produced by the method include a silicon-releasing calcium carbonate and a biodegradable polymer. The silicon-releasing calcium carbonate is a composite of siloxane and calcium carbonate of vaterite phase. The biodegradable fibers may be coated with apatite. When the guided bone regeneration material is immersed in a neutral aqueous solution, silicon species ions are eluted from the calcium carbonate. The guided bone regeneration material excels in bone reconstruction ability.

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