种植体腐蚀及其影响因素的研究进展

近年来纯钛及钛合金由于其良好的化学稳定性和生物相容性已经成为口腔种植体的主要材料。但是在复杂的口腔环境中,种植体仍可能发生各种腐蚀行为,影响种植体的成败。本文就钛和钛合金在口腔中的腐蚀行为及其影响因素进行综述。     

牙科合金微生物腐蚀的研究进展

随着牙科材料的发展,牙科合金如钴铬合金、镍铬合金、钛（钛合金）和贵金属（合金）在口腔修复领域的应用越来越广泛。这些金属在口腔内行使功能时,由于其所处的是一个非常复杂的电解质环境,会发生各种形式的腐蚀。口腔中的金属腐蚀主要包括化学腐蚀和电化学腐蚀两种类型,其中电化学腐蚀又有三种形式：微生物腐蚀、电偶腐蚀、应力腐蚀破裂。     

镍钛正畸弓丝在口腔环境中的腐蚀性变化

口腔环境是一个pH值变化的复杂环境。口腔环境内多种成分能使正畸镍钛弓丝受腐蚀,使其机械性能和生物相容性发生变化。弓丝成分和表面氧化膜的改良可以提高其抗腐蚀抵抗性。本文就口腔环境内镍钛弓丝的腐蚀、抗腐蚀性及其机制作一综述。     

氟化物对纯钛及钛合金的腐蚀作用

氟离子能和牙体组织中的钙结合,促进牙齿的再矿化,因此被广泛应用于口腔保健品。在复杂的口腔环境中,钛材料修复体可能由于氟化物存在而发生各种腐蚀行为,长期存留的腐蚀产物和持续的腐蚀会引起钛材料修复的失败。本文就氟化物对钛和钛合金的腐蚀行为及其其影响因素进行综述。     

钛和钛合金在口腔环境中应用腐蚀的研究进展

本文综述了钛和钛合金在口腔环境中应用腐蚀的相关研究,介绍了卤素元素对钛合金的影响。不同材质与钛合金在口腔环境中的电偶腐蚀,口腔环境中钛合金的微生物腐蚀及在应力集中区域的腐蚀疲劳,钛种植体各部件间的缝隙腐蚀,钛合金中不同的合金元素对其耐腐蚀性能影响等方面的研究进展。     

镍钛基形状记忆合金体外生物相容性研究进展

近等原子比的镍钛形状记忆合金(NiTi-SMA)因具有特殊的形状记忆效应以及超弹性,多年来一直作为口腔正畸矫治弓丝材料应用于临床。由于镍钛基合金材料含有大量镍元素,在口腔环境中可能会由于金属腐蚀作用析出镍离子,对局部组织有致敏甚至致癌的危害。本文回顾NiTi-SMA生物相容性相关历史文献,总结该合金的表面腐蚀、细胞毒性、基因毒性等方面的研究进展,并指出NiTi-SMA表面处理的必要性。     

不同pH值与氟离子浓度对口腔常用金属修复材料电化学腐蚀的影响

目的 研究不同pH值与不同浓度氟离子(F-)对HBIC种植体和常用的四种冠修复金属材料在人工唾液中电化学腐蚀的影响.方法 将5种口腔常用金属,金合金(Au)、镍铬合金(NiCr)、钴铬合金(CoCr)、铸造纯钛(Ti)、HBIC种植钛材(H-Ti)分别置于不同pH值与含和不含F-的人工唾液中,采用动电位极化曲线法测得其自腐蚀电位和自腐蚀电流密度,分析材料的耐腐蚀性.结果 金合金、钴铬合金、镍铬合金的腐蚀电流密度随着H+的浓度增加而变大,差异有统计学意义(P<0.05),铸造纯钛及种植钛材在酸性含氟人工唾液中的腐蚀电流密度和自腐蚀电位变化明显,差异有统计学意义(P<0.05),F-对金合金的耐腐蚀性影响不明显.结论 pH的改变以及含氟环境会加剧种植体及其常用上部冠修复材料的电化学腐蚀性,金合金与纯钛的耐腐蚀性能较强.     

牙科合金腐蚀行为的研究进展

牙科合金正成为口腔科学研究和临床应用中的热点.随着对牙科合金与口腔组织相互作用的深入了解,对合金材料的物理性能和生物相容性等提出了更高的要求,目前正力求研发选择更加适应口腔多变环境的材料.牙科合金在严苛的口腔环境中会发生腐蚀,并引起美学性能、力学性能和生物相容性的下降.因此,了解牙科合金的腐蚀行为并据此进行材料的研究和...     

钛种植体腐蚀与种植体周围炎关系的研究进展

纯钛因具有良好的生物相容性、力学性能及耐腐蚀性,已作为口腔种植体材料广泛应用于临床.然而,钛种植体的耐腐蚀性受环境因素的影响,其在酸、氟化物及微生物等存在的口腔环境中可发生腐蚀,导致钛表面结构的改变,以及钛离子[1]、钛颗粒的产生[2].     

牙科合金腐蚀行为的电化学研究及影响因素

牙科合金在口腔环境中发生的腐蚀主要是电化学腐蚀。电化学方法是研究合金腐蚀的主要手段。合金的电化学腐蚀与材料的成分和量以及组织结构密切相关。口腔电解质溶液环境和微生物对合金的腐蚀也有显著的影响。     

Structure, castability and mechanical properties of commercially pure and alloyed titanium cast in graphite mould

This report is a study of structure, castability, mechanical properties as well as corrosion behaviour of titanium doped with up to 5 weight percentage (wt%) of a series of alloy elements, including Ta, Mo, Nb, Hf, Zr, Sn, Bi and Ag. The results indicate that, with addition of 1 wt% alloy element, Bi and Mo were most effective in enhancing the castability of titanium. With more alloy elements added, the castability values of most alloys more or less decreased. Except Ti-Mo system, all Ti alloys with a fine acicular morphology had the same crystal structure (hcp) as that of c.p. Ti with a typical lath type morphology. When 3 wt% or more Mo was added, a finer orthorhombic alpha' phase was formed. The microhardness and bending strength values of Ti alloys were all higher than those of c.p. Ti. Among all alloys, Ti-Mo system exhibited the highest hardness and strength level. For a certain alloy, the bending strength did not necessarily increase with its alloy content. Except Ti-5Zr and Ti-Mo alloys, the bending moduli of most alloy systems were not much different from that of c.p. Ti. All alloys showed an excellent resistance to corrosion in Hanks' solution at 37 degrees C.     

The electrochemical behavior of titanium and dental casting in modelling oral conditions

The electrochemical behavior of titanium and dental casting alloys in modelling oral conditions With applying dental implants in the oral cavity the direct contact of various metals (titanium and other casting alloys) is unavoidable. Considering the electrolyte characteristic of the saliva, the chances are given that electrochemical processes might occur under such circumstances. The aim of this study was to investigate the electrochemical behavior of titanium and other dental alloys being in direct contact with the oral environment. Nickel-chromium, cobalt-chromium, high palladium content and gold alloys as well as CP grade I titanium cast samples respectively were involved in the study. Test models were made from these metals. As an electrolyte solution (set to pH 4) artificial saliva and 0.9 % NaCl solution were used. The type and the rate of corrosion were assessed with laboratory immersion test and electrochemical polarization method. In case of polarization method a three-electrode measuring-cell was applied. Laboratory exposure tests revealed that titanium resisted corrosion; there was no sign of corrosion at all. The high palladium content alloy and gold alloy behaved similarly. The nickel-chromium and cobalt-chromium alloys showed some signs of corrosion, especially in sites with damaged surface or inhomogeneities on the surface. Results of the laboratory electrochemical experiments correlated with immersion studies graphically illustrated in the paper.     

Corrosion current and pH rise around titanium coupled to dental alloys

Abstract – Corrosion reactions around titanium, usually considered biologically inert, might be provoked by coupling it galvanically with more corrodible dental alloys. Experiments in vitro simulating the conditions of a titanium dental implant or root canal post coupled to an amalgam filling, demonstrated corrosion current densities up to 31 μA/cm² anodic pH values around the amalgam down to 2, and cathodic pH values around the titanium up to 10. The amounts of tin released by the enhanced corrosion, of amalgam might contribute measurably to the daily intake of this element; the corrosion current generated reached values known to cause taste sensations. If the buffer systems of adjacent tissues in vivo are not able to cope with the high pH generated around the titanium, local tissue damage may ensue; this relationship is liable to be overlooked, as it leaves no evidence in the form of corrosion products.     

Assessment of nickel titanium and beta titanium corrosion resistance behavior in fluoride and chloride environments

Objective:To assess the influence of fluoride concentration on the corrosion behavior of nickel titanium (NiTi) superelastic wire and to compare the corrosion resistance of NiTi with that of beta titanium alloy in physiological solution with and without addition of fluoride.Materials and Methods:NiTi corrosion resistance was investigated through electrochemical impedance spectroscopy and anodic polarization in sodium chloride (NaCl 0.15 M) with and without addition of 0.02 M sodium fluoride (NaF), and the results were compared with those associated with beta titanium. The influence of fluoride concentration on NiTi corrosion behavior was assessed in NaCl (0.15 M) with and without 0.02, 0.04, 0.05, 0.07, and 0.12 M NaF solution. Galvanic corrosion between NiTi and beta titanium were investigated. All samples were characterized by scanning electron microscopy.Results:Polarization resistance decreased when NaF concentration was increased, and, depending on NaF concentration, NiTi can suffer localized or generalized corrosion. In NaCl solution with 0.02 M NaF, NiTi suffer localized corrosion, while beta titanium alloys remained passive. Current values near zero were observed by galvanic coupling of NiTi and beta titanium.Conclusions:There is a decrease in NiTi corrosion resistance in the presence of fluoride. The corrosion behavior of NiTi alloy depends on fluoride concentration. When 0.02 and 0.04 M of NaF were added to the NaCl solution, NiTi presented localized corrosion. When NaF concentration increased to 0.05, 0.07, and 0.12 M, the alloy presented general corrosion. NiTi corrosion resistance behavior is lower than that of beta titanium. Galvanic coupling of these alloys does not increase corrosion rates.     

Corrosion of gold alloys and titanium in artificial saliva

Abstract – Two types of gold alloys and one type of pure titanium have been submitted to corrosion in artificial saliva for periods of up to about 2 months. The release of copper, gold or silver from the golod alloys as well as titanium from the titanium matrix was measured with nuclear tracer technique. The physical/chemical state of the corrosion products of gold alloys referring to the ionic state or presence in particulate form has been examined retaining the particulate matter on a glass filter. Copper wad observed to be mainly present in the ionic state. Considerable amounts of gold were observed to be retained on the glass filter explained by the presence of gold in particulate form or as a component of a dispresed colloidal phase. The estimation of the relase of titanium was registered by the tracer nuclide ⁴⁶Sc assumining particulate matter to be deteriorated from the titanium surface.     

钛离子诱导骨吸收的现象及机制

钛及钛合金材料因其良好的抗腐蚀性、生物相容性在种植体等方面得到广泛应用,但是钛及其他离子会从植入物中缓慢释放出来,可能导致周围骨吸收造成种植体植入失败.植入材料及其磨损颗粒所释放出来的金属离子影响成骨细胞、破骨细胞的功能,改变成骨与破骨之间的调控机制,导致成骨减弱、破骨增强,引起骨质的吸收.     

一种生物医用近β钛合金在人工唾液中表面色泽变化的研究

目的 研究一种新型钛合金在模拟口腔环境中的表面色泽的改变,为口腔内存在钛合金种植体或戴用钛合金义齿的患者给予临床指导。方法 将制备好的钛合金试件随机分为8组。每组试件于处理前以及处理后,分别测量色彩值CIE L*a*b*,应用SPSS统计软件分析所得结果。结果 刷洗组试件相对不刷洗组试件表面色泽改变增大,具有统计学意义（P＜0.01）;使用含氟牙膏组的表面色泽改变略大于不含氟牙膏组,但两组改变值无统计学意义（P＞0.05）;通过对pH值和氟离子浓度两个因素的交互效应的统计学分析,提示两因素之间存在交互作用（P＜0.05）,具有统计学意义。结论 近β钛合金的腐蚀程度主要与是否刷洗,以及模拟口腔环境中氟离子浓度和pH值的交互作用有关。     

Corrosion susceptibility of titanium covered by dental cements

Titanium has become a material of great interest in prosthodontics in recent years because of its excellent biocompatibility, corrosion resistance and desirable physical and mechanical properties. In this study, we determined the influence of dental cements on the passivation of titanium. We developed experimental electrodes that associate titanium and dental cements. Polarization resistance of titanium electrodes has been determined for uncovered metal and electrodes covered with five different dental cements. Coverage with zinc eugenate led to more resistance to corrosion, but fluorinated composite such as glass-ionomer and zinc phosphate coverage increased the corrosion susceptibility.     

表面处理技术提高钛-瓷结合强度的研究进展

纯钛因其具有优良的生物相容性、耐腐蚀性以及相对低廉的价格而被广泛地应用于口腔各种修复体的制作,尤其是口腔种植体的制作.但是纯钛在高温下易氧化,在钛表面生成一层过厚的而低附着力的氧化膜,而且钛与瓷粉间热膨胀系数不匹配等因素导致钛-瓷结合强度较低,从而限制了纯钛应用于烤瓷修复体.因此,关于提高纯钛与瓷粉之间结合强度的研究成为一个热点.本文重点对提高纯钛与瓷粉之间结合强度的表面处理技术(喷砂、预氧化、涂层、粘接瓷、化学处理)研究进展进行综述.     

Galvanic corrosion and cytotoxic effects of amalgam and gallium alloys coupled to titanium

The aim of this study was to examine and compare the galvanic corrosion of a conventional, a dispersed high-copper, and a palladium-enriched spherical high-copper amalgam and a gallium alloy coupled to titanium in saline and cell culture solutions, and to evaluate the effects of the couples on cultured cells. The potentials and charge transfers between amalgams and titanium were measured by electrochemical corrosion methods. Cytotoxicity of the couples, as indicated by the uptake of neutral red vital stain, was determined in 24-h direct contact human gingival libroblast cell cultures. Results of this study indicated that before connecting the high-copper amalgams to titanium, the amalgams exhibited more positive potentials which resulted in initial negative charge transfers, i.e. corrosion of titanium. However, this initial corrosion appeared to cause titanium to passivate, and a shift in galvanic currents to positive charge transfers, i.e. corrosion of the amalgam samples. Lower galvanic currents were measured for the amalgam-titanium couples as compared to the gallium alloy-titanium couple. Coupling the conventional or the palladium-enriched high-copper amalgams to titanium did not significantly affect the uptake of neutral red as compared to cells not exposed to any test alloy. However, significant cytotoxic effects were observed when the dispersed-type high-copper amalgam and the gallium alloy were coupled to titanium. Even though the corrosion currents measured for these couples were less than gold alloys coupled to amalgam, these results suggest there is the potential for released galvanic corrosion products to become cytotoxic. These data warrant further investigations into the effects of coupling amalgam and gallium alloys to titanium in the oral environment.