医用金属材料

<正> 一提及人体,人们马上可以想到支持人体的骨干——骨骼。那么什么是人体材料呢?所谓人体材料是指为了恢复由于疾病和事故而丧失的身体机能而用在人体内的金属材料。主要的人体材料有牙科用和整形外科用材料。 金、银牙科材料 众所周知,牙科材料是在与口腔内粘膜、硬组织牙齿以及大气接触的状态下使用。牙科材料的种类很多,从金基合金等贵金属合金和以钴为基的钴合金等低成本金属合     

从矿石或废料中浸出或溶解金

根据美国地质调查局的数据，全世界约有2593吨（约8340万盎司）金是从各种矿产中生产的。此外，还有约943吨再生金来自贵金属废料和废旧电子产品，以及从首饰和牙科医疗部门的废含金合金中回收。所有的湿法提取冶金流程都要利用浸出步骤，产生含金溶液作为中间产物；而从电子和贵金属废料中回收再生金则是基于贵金属的选择性和快速溶解。因此，无论浸出还是溶解操作都需要高腐蚀性的介质，因为在化学性质上，贵金属对大多数酸和碱来说都是惰性的。     

医用贵金属材料的研究与发展

由于贵金属材料具有独特的抗腐蚀性、生理上的无毒性、良好的延展性以及生物相容性，它在医学领域的应用日益拓展。作者在本文着重介绍贵金属材料在牙科(包括牙科汞齐合金和铸造合金)、针灸、体内植入的电子器件及医用生物传感器等方面的研究与发展，分析了牙科用贵金属材料的演变过程等。     

牙科用贵金属合金的现状和未来

牙科用贵金属合金的基本组成为Au -Ag -Cu系合金 ,最主要的有以金为主成分的金合金以及以银和钯为主成分的银 -钯 -铜合金。牙科修复用金合金　牙科用金合金有 5种以上的金属组成 ,最多的有 10种金属组成 ,一般的金合金考虑其化学性质保持金、铂、钯的总含量在 75 %以上 ,并添加Ir、Cu、Sn、Zn等形成均一的合金固溶体。金合金大致可分为加工用金合金ADA标准(美国牙科医师协会标准 )Ⅰ、Ⅱ型 ,铸造用金合金ADA标准Ⅰ、Ⅱ、Ⅲ、Ⅳ型 ,陶瓷材料熔敷用金合金及金钎料。加工用金合金主要考虑的问题是合金的加工性能、延性及增加金含量 ,可…     

从矿石或废料中浸出或溶解金

根据美国地质调查局的数据,全世界约有2 593吨(约8 340万盎司)金是从各种矿产中生产的,此外,还有约943吨再生金来自贵金属废料和废旧电子产品,以及从首饰和牙科医疗部门的废含金合金中回收.所有的湿法提取冶金流程都要利用浸出步骤,产生含金溶液作为中间产物;而从电子和贵金属废料中回收再生金则是基于贵金属的选择性和快速溶解.因此,无论浸出还是溶解操作都需要高腐蚀性的介质,因为在化学性质上,贵金属对大多数酸和碱来说都是惰性的.     

钛及钛合金在牙科领域应用的新动向

日本东京医科齿科大学塙隆夫教授对钛及钛合金在牙科领域的应用、钛的组织适应性以及牙科植入物与骨的结合性作了简要概述。齿列矫正用丝的材质有不锈钢、Co-Cr合金、Ti-Mo合金、Ti-Ni合金、橡胶合金等。其中,Ti-Ni合金丝具有超弹性,可持续发挥与牙移动相适应的矫正力,在临床上得到了广泛的应用。此外,在牙本质上用于固定矫正丝的托架以及为支撑矫正丝而埋入颚骨或在骨表面放置的丝也采用的是与组织具     

贵金属牙科材料的应用及发展

贵金属具有优良的耐腐蚀性,生物相容性,良好的加工性和处理性,广泛用作牙科材料,在牙科修复中起着重要作用,综述了牙科用贵金属的种类,性能及有关标准,应用及发展,分加工合金,铸造合金及烤瓷合金介绍了主要牙科材料Au-Ag-Cu合金,Ag-Pd-Cu合金,Au-Ti 合金,相关焊料合金及微量添加元素的作用。     

牙用合金

用作牙业上的金属材料范围很广:从纯金属到简单的固溶体合金以至复杂的多相合金;从金、银、铂、钯等贵金属到铜基、钴—铬基、不锈钢等贱金属合金,多种多样。对牙科材料的基本要求是具有高的抗腐     

《贵金属》季刊启事

本刊是国家科委批准的部一级专业技术刊物。1980年创刊,向全国公开发行。集纳全部贵金属(包括金、银、铂、钯、铑、铱、锇、钌八个元素)的矿物资源、选矿、冶炼、分离提纯、废料再生、化台物、催化剂、电镀、厚膜电子浆料、贵金属合金、急冷金属、形状记忆材料、饰品牙科、材料应用、物理化学测试,合金相图实验资料     

《贵金属》季刊启事

本刊是国家科委批准的部级专业技术刊物。1980年创刊,向全国公开发行。集纳全部贵金属(包括金、银、铂、钯、铑、铱、锇、钌八个元素)的矿物资源、选矿、冶炼、分离提纯、废料再生、化合物、催化剂、电镀、厚膜电子浆料、贵金属合金、急冷金属、形状记忆材料、饰品牙科、材料应用、物理化学测试,合金相图实验资料等方面     

牙科用钛合金研究现状

本文综述了国内外牙科用钛合金发展过程及应用现状；介绍了现有牙科用钛合金弹性模量、抗拉强度、压缩强度、延伸率等力学性能，卤素元素对钛合金腐蚀的影响，不同材质与钛合金在口腔环境中电偶腐蚀，口腔环境中钛合金的微生物腐蚀，牙科钛合金表面特性特别是表面粗糙度对水基液体润湿性影响，设计新型牙科用钛合金时推荐使用的合金元素种类及计算设计采用的d-电子合金设计法等方面研究成果，并指出了目前存在的问题及努力的方向。     

Untersuchungen zur Resistenz von Edelmetall-Dentallegierungen

A study of the dealloying resistance of noble metal dental alloys. In connection with the development of low gold dental alloys the corrosion resistance of homogeneous gold-palladium-silver-experimental alloys was investigated in a chloride solution. Analogous measurements were made with several noble metal containing intermetallic phases which may be present in dental alloys of more complex composition. The results indicate a high corrosion resistance of the homogeneous gold-palladium-silver-alloys, since their free corrosion potentials are always situated within a region of their anodic polarization curves, where the current density of metal dissolution is extremely low. Within the composition limits of these alloys the substitution of gold by palladium did not reduce the extension of this “region of immunity” in a significant way. Intermetallic phases, however, as present in the systems silver-tin, silver-palladium-tin and silver-palladium-indium show a clearly restricted “region of immunity” and, at the free corrosion potential, are dissolved at a relatively high rate.     

金属系牙科材料的应用现状及部分元素的毒副作用

本文对金属纱牙科材料的组成、性能，适用场合，存在问题及发展趋势进行了综合评述。认为汞、镍，铜，铝，铍，铬，钴，钒，钯元素均具有细胞毒性作用，在牙科材料及其它生物医学材料中应尽量避免使用；而元素钛、铌，锆，锡，钼，钽和铁是无毒性元素，可以作为改善生物医学材料力学性能，耐蚀性能及生物相容性的候选元素，为新型牙科合金材料及其它生物医学材料的开发研究提供选材依据。钛合金作为牙科材料是未来牙科材料的发展趋势     

新型牙科用Ti合金人工体液中电化学腐蚀研究

利用电化学方法研究了新型牙科用Ti合金在Hank's人 工模拟体液的腐蚀情况.XPS分析表明该合金表面形成的氧化膜为Nb2O5、Mn2O3、TiO2，实验表明：由于在空气中形成了这种致密的具有保护性的氧化膜，在Hank's人工模拟体液中合金的自腐蚀电位正移到045～059 V，并出现钝化现象.虽然Cl-虽然可以加速氧化膜的溶解，但阳极化曲线表明在Hank's人工模拟体液中新型牙科用Ti合金的氧化膜依然可以保持完整；腐蚀速度表明在Hank's人工模拟体液中新型牙科用Ti合金耐腐蚀级别为优.     

Electrochemical investigations regarding the bioavailability of silver after potentiodynamic corrosion load of precious metal alloys Part 2: Dental alloys

The spectrum of commercial dental alloys has been essentially expanded during the last years. The toxicological effects of dental alloys depend mainly on their element specific corrosion behaviour in the oral cavity. The present study demonstrates the electrochemical boundary conditions regarding the possible formation of AgCl-corrosion products, for which cytotoxic effects has been established, by means of specially adapted electrochemical in-vitro test programs. The prevalence of the developed corrosion mode was proved for two electrolytes and four daily used dental alloys containing different amounts of silver. The results show, that a biological relevant assessment of the released silver ions in both electrolytes, induced by anodic metal dissolution, is only reliable if the measurement takes into account the silver ions within the electrolyte as well as the superficial immobilized amount of silver chloride corrosion products. Thus especially from a biological point of view, interface processes like the formation of immobilized corrosion products seem to be a relevant parameter for the complete testing of biocompatibility of metallic biomaterials. To sum up it can be concluded, that the dental alloys investigated in the course of this study have not shown any adverse susceptibility to corrosion with respect to the clinical practice and can therefore be classified as well biocompatible.     

口腔科用人工替代金属材料的耐蚀性能

通过模拟试验液中溶出的离子量，比较了口腔科用金属及合金的耐蚀性能，讨论了口腔科用金属及合金在成型及使用过程中其耐蚀性能下降的因素，如铸造、研磨、异种金属间的接触等。介绍了近年开发的口腔科用新型合金及其耐蚀性能。     

Surface and Subsurface Defects Studies of Dental Alloys Exposed to Sandblasting

The defects created in commercial dental alloys during blasting with alumina particles propelled in compressed air under pressure 0.1 and 0.4 MPa have been studied using positron annihilation spectroscopy, scanning electron microscopy and X-ray diffraction. It was observed that higher pressure causes the increase in roughness and damaged zone range. The type of defects was determined as vacancies on dislocations. The defect concentration decreases with the depth and depends on alloys' type and applied pressure. The Rutherford backscattering spectroscopy and variable energy positron beam studies indicate shallow alumina deposition in material and show that small pressure of 0.1 MPa is not enough to remove metal surface oxides completely in 60 s in all studied dental alloys.     

2种牙科贵金属铸造合金的细胞毒性研究

采用四甲基偶氮唑盐微量酶反应比色法(MTT法)对自行研制的2种Au-Ag-Pd-Cu牙科铸造合金的细胞毒性进行了研究。并用相差显微镜对细胞形态进行了观察分析。试验使用的细胞株为小鼠结缔组织成纤维细胞(L-929)，培养液为含5％小牛血清(FBS)的RPMI1640。结果表明：细胞在2种Au-Ag-Pd-Cu牙科铸造合金的浸渍液中培养3d和5d后，细胞形态良好，生长旺盛；2种合金的细胞毒性级别为0—1级，具有良好的细胞相容性。     

Effects of tetrahedral amorphous carbon film deposited on dental cobalt–chromium alloys on bacterial adhesion

The dental cobalt–chromium alloys are an important biomaterial used in making artificial dentures. Bacterial adhesion to cobalt–chromium alloys usually results in severe complications such as periodontal infection, secondary caries, and denture stomatitis, which have severe adverse impacts on human health. Therefore, an effective method is needed to reduce the bacterial adhesion to dental cobalt–chromium alloys. The aim of this study was to investigate the effects of ta-C films deposited on a dental cobalt–chromium alloy on the adhesion of Streptococcus mutans (ATCC175), Actinomyces viscosus (ATCC19246) and Candida albicans (ATCC76615). A filtered cathodic vacuum arc (FCVA) technique was used to coat the cobalt–chromium alloy with a ta-C film. Atomic force microscopy (AFM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) were used to analyze the surface characteristics of the coating. Surface roughness was detected. Surface free energy and its components were calculated by measuring the contact angle. The results showed that the maximum sp³ fraction was achieved at 200 V substrate bias voltage. Compared with uncoated specimens, the ta-C film coated specimens had a lower surface roughness, a higher surface energy and a higher hydrophilicity. Most importantly, the adhesion of the three tested bacterial strains to the ta-C film coated cobalt–chromium alloy was significantly decreased. These results showed that ta-C film surface treatment could significantly reduce the bacterial adhesion to dental cobalt–chromium alloys, suggesting the potential of ta-C film surface treatment in artificial denture applications.     

Vergleichende Korrosionsprüfung von dentalen Legierungen im Laborbioreaktor

Comparative corrosion test of dental alloys in a bioreactor The demands in the modern prosthetics require the insertion of ceramics, polymers, metals and composites in the oral cavity. To realise dental applications of ceramics and polymers intensive efforts was made in research and development in the last years. Nevertheless metallic materials possess one of the most important positions in biomedical engineering. The excellent biofunctionality of the metallic dental materials is responsible for this situation. One of the greatest disadvantages by integrating metallic materials in the human organism is the great susceptibility to corrosion in the biological environment. Experiments to describe the corrosion behaviour under simulated in-vivo conditions should be used to estimate the biocompatibility of the inserted biomaterials. The quality of the simulated biological environment defines the clinical relevance of these experiments. In this work a research team of the ?Thüringer Arbeitsgemeinschaft Biomaterial e.V.”? reports about corrosion experiments on precious and non-precious dental alloys in an in-vitro test system, which represents a new simulation equipment for the development of a artificial oral cavity.