牙科铸造合金的生物相容性及影响因素

随着牙科铸造合金的广泛应用和新牙科铸造合金的不断推出，无论临床应用还是新合金的研制，生物相容性都是一个重要的影响因素。本从生物学反应及其影响因素方面对牙科铸造合金的生物相容性问题加以综述。     

牙科合金生物相容性评价:细胞培养法的可行与可信?

背景:随着口腔金属材料在修复学领域的大量应用,逐渐暴露出一定的生物毒性。细胞培养法以其操作简便、敏感性高、研究周期短、效费比高等特有的优点成为检测材料毒性的有效途径。目的:概括体外细胞培养法评价牙科用合金的生物相容性研究状况。方法:以casting alloy,Biocompatibility,Cytotoxicity,Cytokine为检索词,检索Pubmed数据库;以铸造合金,生物相容性,细胞毒性,炎症因子为检索词,检索CNKI数据库。纳入牙科用合金对细胞生物活性影响方面的内容。排除牙科用合金的理化特性以及力学方面的研究。结果与结论:当牙龈组织金属离子释出量超过生理耐受量时,可能导致机体毒性,并改变该区域细胞代谢,出现细胞不同程度的损伤(包括细胞活性,DNA/RNA/蛋白质的合成,胞膜的完整性等)及局部免疫学的变化,严重时可使该区域细胞代谢停止。     

牙科合金中钯的作用和牙科钯合金

牙科钯合金作为牙科贵金属合金的替代材料之一，越来越广泛地受到重视，因为它具有与贵金属合金如金合金相似的性能，又克服了贱金属合金的不良的生物相容性。本文概述了金属元素钯（Ｐｄ）的理化性质和生物学作用，详细叙述了牙科合金中加入钯后对合金合金理化性能、机械性能、生物学性能的影响及相关机理，并简单描述了已用于临床的牙科高钯和低钯合金。     

牙科合金中钯的作用和牙科钯合金

牙科钯合金作为牙科贵金属合金的替代材料之一，越来越广泛地受到重视，因为它具有与贵金属合金如金合金相似的性能，又克服了贱金属合金的不良的生物相容性。本文概述了金属元素钯（ Ｐｄ）的理化性质和生物学作用，详细叙述了牙科合金中加入钯后对合金理化性能、机械性能、生物学性能的影响及相关机理，并简单描述了已用于临床的牙科高钯和低钯合金。     

牙科金属材料人类细胞培养研究

在口腔材料的应用中,牙科金属合金材料受机械、化学、热和电流加工的影响,推测可能是材料腐蚀作用损害了物理和机械的铸造特性,并可引起局部和整体过敏样的有害作用。这主要与低贵和非贵合金有关,但有时也可涉及到贵合金,由此阐明了非合金铸造金属材料作为牙科材料是需要的。由于铸造技术的进一步改进,能加工非合金钦作为牙科铸造修补物,但非合金和合金钛主要用作植入材料,据报道     

用物理蒸发沉积法制作牙科修复体涂层

目前大多数牙科修复体是用Co-Cr-Mo合金制成的。Co-Cr-Mo合金具有良好的综合性能,如硬度、抗张强度和生物相容性。但由于该合金的耐腐蚀性能不够理想,所以用物理蒸发沉积法在Co-Cr-Mo合金表面进行离子镀,形成TiN涂层后可使材料符合制作牙科修复体的要求,它具有机械强度高、耐磨蚀性能好、美观(呈金黄色)     

芝加哥Northwestern大学生物材料中的学位研究

Northwestern大学强调研究的是牙科材料和用于矫形外科材料。所设计的生物材料学位计划是教育和训练科学家进行研究以及对于牙科学和医学进行材料科学和工程方面的应用教育。现代研究计划包括新牙科汞合金研究,用于牙科铸造的合金研究,聚合物和修复材料,用于牙科的水门汀,用于颌面外科的材料,瓷-金属结合物,用于矫形外科的骨水泥,牙科修复和矫形植入物的失败分析研究,以及     

牙科铸钛系统

钛以其优良的理化特性和相容性，正日益受到口腔修复学者的重视。现已开发出多种类型的牙科铸钛系统。随着铸造成功率的不断提高，质量更加可靠，牙科铸钛技术已开始进入临床实用阶段。本文从牙科铸钛系统的组成，特点及性能比较等方面综述了牙科铸钛技术的现状及发展。     

三种心血管支架用金属材料的表面特性与生物相容性

考察了316L不锈钢、NiTi合金和TLM钛合金的表面特性、血液相容性和内皮化能力,以筛选心血管支架材料。结果表明,316L不锈钢具有较好的血液相容性,内皮细胞生长良好,但耐蚀性差;NiTi合金的耐蚀性和血液相容性优良,内皮细胞生长状况良好。TLM合金由生物相容性元素组成,其耐蚀性好,但表面粗糙度较高,亲水性差,影响了材料的血液相容性和内皮化能力。作为心血管支架材料,三种材料中NiTi合金具有最好的生物相容性。     

牙科陶瓷合金应用研究现状

本文从应用材料学角度介绍了牙科陶瓷合金的一般要求、各类合金的组成及不同成份的作用、合金与瓷结合的机制以及影响结合强度的因素，重点介绍了镍铬陶瓷合金、富钯陶瓷合金、钴铬陶瓷合金、钛及钛合金等，旨在推动我国牙科陶瓷合金的研制。     

Measurement of absorbed doses near metal and dental material interfaces irradiated by x- and gamma-ray therapy beams

Soft-tissue damage adjacent to dental restorations is a deleterious side effect of radiation therapy which is associated with low-energy electron scatter from dental materials of high electron density. This study was designed to investigate the enhancement of dose to soft tissue (or water) close to high electron-density materials and to measure the detailed lateral and depth-dose profiles in soft-tissue-simulating polymer adjacent to planar interfaces of several higher atomic-number materials: 18-carat gold dental casting alloy; Ag-Hg dental amalgam alloy; Ni-Cr dental casting alloy; and natural human tooth structure. Interleaved stacks of calibrated thin radiochromic dosimeter films and tissue-simulating polymer were used for these measurements. Assemblies of these polymer-dosimeter stacks on both sides of the dental materials were irradiated in one fixed direction by collimated 60Co gamma-ray or 10 MV x-ray beams directed perpendicularly to the material interfaces. In another test, designed to simulate more closely therapeutic treatment conditions, a phantom constructed on both sides of a row of restored and unrestored whole teeth (restoration materials: gold alloy crown; Ni-Cr alloy crown; Ag-Hg mesial-occlusal-distal (MOD) amalgam filling; unrestored tooth) was irradiated in one fixed direction by the collimated photon beams. Results indicate that the dose-enhancement in 'tissue' is as great as a factor of 2 on the backscatter side adjacent to gold and a factor of 1.2 adjacent to tooth tissue, but is insignificant on the forward-scatter side because of the predominant effect of attenuation by the high-density, high atomic-number absorbing material.     

Preliminary studies of the histopathological responses to Ti-13% Cu casting alloys

A preliminary study of some of the biological properties of a new dental casting alloy (Ti-13% Cu) was undertaken by employing the skeletal muscle implantation test in rabbits. Routine histopathological and chemical analysis techniques were utilized to study in vivo tissue reactions of skeletal muscle to this alloy. A moderately thick, somewhat cellular fibrous connective tissue capsule surrounded the implants after 2 wk. Remodelling of the fibrous tissue into a thin acellular tissue capsule occurred at 52 wk after implantation. Chemical analyses failed to detect deposition of either Ti or Cu corrosion products at the implant sites or within major organs.     

Evaluation of the biocompatibility of a Ni-Cr-Mo dental alloy with human gingival explant culture in vitro: morphological study, immunodetection of fibronectin, and collagen production

This study was undertaken to evaluate the biocompatibility of a Ni-Cr-Mo dental casting alloy by an in vitro explant culture method. Through ultrastructural features, the immunolabelling of fibronectin, and the immunodetection of type I and III collagen production, we investigated the behaviour of gingival cells (both fibroblasts and epithelial cells) in contact with the alloy in comparison with control cultures. Our results indicate that cultured gingival cells present a well preserved ultrastructure and synthesized fibronectin (the main glycoprotein involved in adhesion to substrates). The alteration of collagen production concerned only type III collagen which decreased significantly in the cultures on the dental alloy.     

The biocompatibility of a dental Ag-Pd-Cu-Au-based casting alloy and its structural components

The biocompatibility of type III casting gold alloy, an Ag-Pd-Cu-Au-based dental casting alloy and its two main structural components, a CuPd-rich and an Ag-rich phase, was studied after subcutaneous implantation for 7 weeks in 20 guinea pigs. The Ag-Pd-Cu-Au alloy was surrounded by a capsule of immature collagen with fibroblasts and an increased vascular supply. The CuPd-rich component induced and maintained an acute inflammation with highly vascularized granulation tissue. The tissue reaction to the Ag-rich component and the Au-based alloy was slight. Ten of the guinea pigs were sensitized to PdCl2 prior to the implantation period, but this caused no enhanced tissue reaction, except for an increase in the number of mast cells around three of the alloys.     

Silica coatings formed on noble dental casting alloy by the sol-gel dipping process.

The sol-gel dipping process, in which liquid silicon alkoxide is transformed into the solid silicon-oxygen network, can produce a thin film coating of silica (SiO2). The features of this method are high homogeneity and purity of the thin SiO2 film and a low sinter temperature, which are important in preparation of coating films that can protect from metallic ion release from the metal substrate and prevent attachment of dental plaque. We evaluated the surface characteristics of the dental casting silver-palladium-copper-gold (Ag-Pd-Cu-Au) alloy coated with a thin SiO2 film by the sol-gel dipping process. The SiO2 film bonded strongly (over 40 MPa) to Ti-implanted Ag-Pd-Cu-Au alloy substrate as demonstrated by a pull test. Hydrophobilization of Ti-implanted/SiO2-coated surfaces resulted in a significant increase of the contact angle of water (80.5 degrees) compared with that of the noncoated alloy specimens (59.3 degrees). Ti-implanted/SiO2-coated specimens showed the release of many fewer metallic ions (192 ppb/cm2) from the substrate than did noncoated specimens (2,089 ppb/cm2). The formation of a thin SiO2 film by the sol-gel dipping process on the surface of Ti-implanted Ag-Pd-Cu-Au alloy after casting clinically may be useful for minimizing the possibilities of the accumulation of dental plaque and metal allergies caused by intraoral metal restorations.     

Beryllium localization in base metal dental casting alloys

Investigation of dissolution of base metal dental casting alloy constituents in aqueous solutions revealed an unexpectedly high level of beryllium as compared with the other constituents. Analysis of atomic emission spectroscopy is presented here showing the outer surface (0-100 A) is decidedly enriched in beryllium as compared with the bulk composition of the alloy. This localization is consistent in all samples and forms of the alloy tested.     

An analytical method for quantitative estimation of the cytotoxicity of dental alloys

INTRODUCTION　　The two mostimportantcriteria fordental materialsare their bio-functionalandbio-compatible endurance within the anticipated life-span of the dental restoration inthe mouth.The bio-compatibility of amaterial relates mainly to theallergenici…     

Biocompatibility and in vivo gentamicin release from bioactive sol-gel glass implants

The objective of this investigation was to study the compositional influence on the corrosion behavior of Ni-Cr-Mo dental casting alloys in acidic artificial saliva. Cyclic potentiodynamic and potentiostatic tests were used to evaluate the corrosion behavior of different Ni-Cr-Mo dental casting alloys in deaerated artificial saliva with pH 5 at 37 degrees C. Optical microscope observations were made following the cyclic potentiodynamic tests. Surface chemical analyses were characterized by X-ray photoelectron spectroscopy and auger electron spectroscopy following the potentiostatic tests. The results show that the corrosion resistance of the Ni-Cr-Mo casting alloys investigated is associated with the formation of passive film containing Ni(OH)(2), NiO, Cr(2)O(3), and MoO(3), on the surface. The pitting potential and passive range, respectively, were statistically different among the different Ni-Cr-Mo alloys. The Ni-Cr-Mo alloys with higher Cr ( approximately 21%) and Mo ( approximately 8%) contents had a much larger passive range in the polarization curve and were immune to pitting corrosion due to the presence of high Cr (maximum approximately 31-35%) and Mo (maximum approximately 12%) contents in the surface passive film. The presence of Ti lower than 4% in the Ni-Cr-Mo casting alloy had no effect on corrosion resistance. A pitting resistance equivalent (PRE) of about 49 could provide the Ni-Cr-Mo alloy with a good pitting corrosion resistance.     

牙科钛铸件的表面处理

纯钛在高温下化学性质活泼，故其铸件表面易形成较厚的污染层影响其固有的优良型化性质，即使在常温下暴露在空气中的纯钛表面也易形成一层氧化膜，使其表面光泽变暗，因此钛铸件的表面处理与其他牙科常用合金铸件比较就显著更为重要。本文就牙科钛铸件的表面处理工艺归纳为物理研磨、化学研磨、电解和表面改性等四个方面详细综述。     

Mold filling of titanium alloys in two different wedge-shaped molds

Pure titanium and titanium alloys are potential materials for the fabrication of cast dental appliances. One important factor in producing sound castings is the capacity of the metal to fill the mold. This study used a wedge-shaped mold to compare the mold filling of titanium with that of conventional dental casting alloys. The metals used were CP Ti, Ti-6Al-7Nb, Ti-6Al-4V, Ti with 1 and 4wt% Cu and ADA Type III gold alloy and an Ni-Cr alloy. The castings were cut into four pieces parallel to the triangular surface. Mold filling was evaluated as the distance between the tip of the cast wedge and theoretical tip of the triangle. The mold filling of the gold alloy was superior compared to all the metals tested, while the mold filling of the Ni-Cr alloy was the worst. There were no statistical differences at the 30 degrees marginal angle for all the cast titanium metals. At the sharper 15 degrees angle, CP Ti and Ti-6Al-7Nb was superior to both the Ti-Cu alloys. Although the mold filling of titanium was inferior compared to the gold alloy, the data justify the use of titanium for the production of dental appliances.