| 초록 |
Approximately more than 70% of the orthopedic implant products are metallic biomaterials which consist of titanium and titanium alloys, cobalt-chromium-molybdenum (CCM) alloys and austenitic stainless steels. The former two alloys, i.e., titanium alloys and CCM alloys are mostly used as artificial hip and knee joint. Orthopedic reconstructive market in Japan is being driven by an aging population and also increased adoption by younger patients. In addition, as for the recent topics for metallic biomaterials, the stent technology needs metallic materials with higher strength and high elastic modulus as well as higher bio-and-MRI compatibility. It is pointed out that CCM alloys is a promising candidate for the stent application because of its high Young’s modulus and strength as well as lower magnetization, compared to austenitic stainless steel. According to the recent statistics in Japan, Japan’s market of the medical devices utilizing the metallic biomaterials is anticipated to sum up to 2,711 hundreds million yen (24.6 hundreds million US dollars) in 2011 fiscal year and increases by 3% in every year. However, almost 90% of the total sum of the market is imports from overseas. Therefore, Japanese major company in the orthopedic implant market is eager to increase the market share of biomedical devices. Historically, in 1987, Nakashima Propeller Corporation developed artificial knee joints made of titanium alloy. In 2008, Nakashima Medical Co., Ltd. was founded to make artificial joints suitable for Japanese skeletal structure. Now, they are developing artificial knee joint and wear resisting UHMWPE containing vitamin E. Nakashima Medical has been developing optimal products for Japanese and Asian bone structures and lifestyles to realize a better and healthier life for each individual patient. In 2004, JMM (Japan Medical Materials Corporation) was born by integrating the medical material businesses of Kyocera Corporation and Kobe Steel, Ltd. Material and processing technologies of ceramics and metal, which are core technologies of both companies, contribute to the progress of modern medicine. JMM has developed the new titanium alloy suitable for various orthopedic implants. In 2002, before the integration of the two companies, Kobe’s vanadium-free type-titanium alloy, Ti-15Mo-5Zr-3Al, was standardized by JIS as titanium alloy for medical use. In 2007, it was successively standardized by ISO as titanium alloy for medical use. For direct bonding of implant made of titanium alloy with live bone, JMM developed and adopted alkaline- and heat-treating method to their products, which is effective compared with other processing such as HA coating. The alkaline- and heat-treating method was licensed from Japan’s FDA in 2007. As of April 1, 2012, Japan Medical Materials Corporation has changed its company name to KYOCERA Medical Corporation. In academia, one of the major trends of R&D is the technologies to remove nickel from titanium alloys, CCM alloys and shape memory alloy such as Ni-Ti alloy, and vanadium from titanium alloys. A large number of researchers are interested in reducing the Young’s modulus of titanium alloys. In addition, reducing the magnetization of the metallic implant materials becomes taken into consideration for developing the medical devices, because imaging artifacts of MRI and displacement of implanted materials, caused by the magnetization of the materials, hinder diagnosis using MRI. Thus besides biocompatibility, since the MRI-compatibility is considerably needed for the metallic implant materials, investigation into the reduction of the magnetization of conventional CCM alloys is carried out in research group in Japan. In this presentation, the recent topics of R&D for metallic biomaterials in Japan will be described in more detail. |
