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。     

羟基磷灰石涂层处理的多孔镍钛合金溶血性及细胞黏附性评价

目的通过研究经羟基磷灰石(HA)涂层处理后多孔镍钛(NiTi)合金的溶血率及成骨细胞在其表面的附着、增殖及分化情况,评价其体外生物相容性。方法测定经HA涂层处理的圆盘状多孔NiTi合金(NiTi-HA组;直径10mm,厚2mm)的生物相容性,未经涂层处理的多孔NiTi合金(NiTi组)及致密纯钛(Ti组)试样设为对照组。采用分光光度法分析其溶血性能;将成骨细胞接种于试样表面,用扫描电镜(SEM)观察成骨细胞黏附形态,MTS法及碱性磷酸酶(ALP)试剂检测细胞附着、增殖情况及ALP活性,对数据进行重复测量方差分析。结果 NiTi-HA组、NiTi组及Ti组试样的溶血率分别为(0.30±0.11)%、(0.51±0.07)%及(0.27±0.06)%,均低于国家标准(YY/T0127.1)规定的5%。SEM观察显示,NiTi-HA组及NiTi组试样细胞黏附形态良好。NiTi-HA组试样表面细胞附着及增殖数量均高于NiTi组试样(P值分别为0.000与0.001)。NiTi-HA组及NiTi组试样表面细胞ALP活性无差异(P=1),但均高于Ti组试样(P值分别为0.001与0.0004)。结论 NiTi-HA组、NiTi组及Ti组试样均无溶血作用;NiTi-HA组较NiTi组更有利于成骨细胞附着和增殖,且ALP活性均高于纯钛。     

钛种植体表面生物活性涂层的应用进展

钛及钛合金因其良好的生物相容性、耐腐蚀性和优异的机械性能被广泛应用于种植体材料.但其在自然条件下,表现为惰性金属,需要通过表面改性等方法来获得生物活性涂层.本文拟对钛种植体表面生物活性涂层的分类进行综述.     

水热合成法制备羟基磷灰石生物涂层的体内及体外实验研究

目的对水热合成法制备羟基磷灰石生物涂层材料的细胞相容性及动物体内植入体与骨界面的状况进行研究.方法水热合成法制备羟基磷灰石涂层,采用细胞培养和动物实验评估涂层材料的生物相容性.结果成骨细胞在涂层材料表面具有良好的细胞增殖率,碱性磷酸酶活性逐渐增加.植入动物体内1月后即有骨组织与涂层材料结合,3月后骨结合量增加.涂层材料在体内稳定,未见溶解脱落.结论水热合成法制备的羟基磷灰石生物涂层材料具有良好的生物效应.     

镍钛根管锉的表面处理对其抗磨与切削效率的影响

根管锉能否有效地去除牙本质决定于其表面是否由不锈钢或镍钛(NiTi)构成。镍钛根管锉作为一种有效的根管预备器械,其表面特征影响其机械性能。由于NiTi器械与含氧和碳的空气接触,所以器械表面至中心的镍钛成分依次升高。高压灭菌可增加NiTi表面氧化量,降低其切削能力。最近,学者们引进各种表面工程技术,通过生成表面硬质涂层而改变器械硬度和耐磨性能。本研究目的是评价热氮和氮离子植入技术能否提高NiTi根管锉的耐磨性能和切削效率。     

水热合成法制备羟基磷灰石生物涂层的体内及体外实 …

目的：对水热合成法制备羟基磷灰石生物涂层材料的细胞相容性及动物体内植入体与骨界面的状况进行研究。方法：水热合成法制备羟基磷灰石涂层,采用细胞培养和动物实验评估涂层材料的生物相容性。结果：成骨细胞在涂层材料表面具有良好的细胞增殖率,碱性磷酸酶活性逐渐增加。植入动物体内１月后即有骨组织与涂层材料结合,３月后骨结合量增加。涂层材料在体风稳定,未见溶解脱落。结论：水热合成法制备的羟基磷灰石生物涂层材料具有     

口腔医用镍钛合金高级氧化法改性的离子析出量研究

目的:比较口腔医用镍钛合金经过高级氧化法改性前后,材料表面Ni+的析出量.方法:对镍钛合金采用高级氧化法改性,将改性前后的镍钛合金浸泡在pH6-7的人工唾液中,分别在第1、2、3、4、5周末时,取出试件,应用AA-240型原子吸收光谱仪检测浸泡液中的Ni+析出量.结果:镍钛合金高级氧化法改性前后,Ni+析出量随着时间均...     

新型负载生物离子种植体涂层的抗菌学研究

目的:将具有抗菌学效应的生物离子合成至种植体表面化学组分当中并研究其体外抗菌学性能。方法:采用电化学方法将Cu离子导入种植表面从而达到修饰表面化学组分的目的,同时检测样品表面离子的释放情况;并针对所制备的材料进行如下生物学检测:(1)激光共聚焦检查测材料表面细菌状态;(2)计算抗菌学效率。结果:材料学检测证实随着时间的推移,表面涂层能够以持续、缓慢的速率释放Cu等离子。抗菌学实验检测显示出负载离子活性涂层表面细菌存活率大大降低,对其抗菌效率进行分析得到了一致的结果。结论:通过电化学法能够在种植体表面成功制备出负载生物离子缓释涂层,且该涂层具有良好的抗菌能力,为将来种植体周围炎的解决提供新的思路。     

多孔镍钛合金牙种植材料的体外生物安全性检测

目的检验多孔NiTi合金牙种植材料的生物相容性。方法分别通过溶血试验、细胞毒性试验（MTT法）评价多孔NiTi合金材料的生物安全性。结果多孔NiTi合金材料无溶血现象，不影响凝血功能；MTT试验显示L929细胞在多孔NiTi合金牙种植材料浸提液中生长良好，细胞毒性为1级。结论多孔NiTi合金材料具有较好的生物安全性。     

3种烤瓷铸造合金的离子析出研究

目的 研究3种常用烤瓷非贵金属合金模拟烤瓷前、后在体外细胞培养液中离子析出的量及种类。方法 用失蜡法铸造3种常用烤瓷非贵金属合金试件,镍铬合金、钴铬合金、镍钛合金,置于DMEM体外细胞培养液中30 d后重新打磨,模拟烤瓷加热过程,之后放回DMEM体外细胞培养液中浸泡30 d,用电感耦合等离子发射光谱法(ICP-AES)观察烤瓷处理前、后3种合金离子的析出的改变,扫描电镜(SEM)对表面形态观察。结果 (1)3种合金离子析出总量依次为镍铬合金>钴铬合金>镍钛合金,(2)模拟烤瓷程序后3种合金离子析出总量减少,差异具有统计学意义(P<0.05)。结论 3种常用烤瓷非贵金属合金中,镍铬合金的离子析出量最大,生物相容性最差;烤瓷过程会促进这3种合金表面氧化膜的生成,使合金的耐腐蚀性有所增强。     

九种镍钛矫正弓丝相变温度的对比研究

目的 确定临床常用的9种镍钛矫正弓丝的马氏体相、奥氏体相、R相温度以及相变温度范围,为镍钛矫正弓丝的力学性能研究提供依据.方法 采用差热扫描(differential scanning calorimetry,DSC)技术,确定9种临床常用镍钛矫正弓丝(A组:Smart SE圆丝;B组:Kleen PakRTM圆丝;C组:中国镍钛牙弓丝圆丝;D组:Nitinol heat-activated圆丝;E组:Smart SE方丝;F组:Damon CuNiTi方丝;G组:L&H Titan方丝;H组:中国镍钛牙弓丝Ⅰ方丝;Ⅰ组:中国镍钛牙弓丝Ⅱ方丝;每组3根弓丝)的相变过程和相变温度.结果 A、B、D组镍钛矫正弓丝的奥氏体相结束温度(austenite finish,Af)分别为22.4℃、21.9℃、22.5℃,低于25℃,在口腔温度下不能再发生相变,没有形状记忆性能;C、H组镍钛矫正弓丝在DSC仪扫描范围内未发现相变状态.E、G、I组镍钛矫正弓丝在室温下为马氏体相和奥氏体相的混合体,Af分别为34.3℃、36.6℃、38.5℃,与口腔温度接近,具有形状记忆性能.F组镍钛矫正弓丝Af为61.5℃,远高于口腔温度,在口腔环境中也为马氏体相和奥氏体相的混合体,在口腔温度较高的情况下才能完全转变为奥氏体相,具有形状记忆功能.结论 临床常用的9种镍钛矫正弓丝的相变温度和相变过程各不相同,并非所有弓丝均具有形状记忆性能,所以应根据临床治疗目的选用不同的弓丝.     

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与手用不锈钢器械相比，镍钛机用器械具有良好的超弹性、形态记忆功能，因而被广泛运用于临床。然而镍钛机用器械的分离也给临床带来了很大的困扰。为了改善其安全性，根管预备器械不断发展创新，新型镍钛根管器械也在不断涌现。本文从镍钛器械几何形状、运动方式、机械物理性能以及根管预备混合系统4个方面介绍目前常见的以及新型镍钛器械特性。     

NiTi根管器械表面耐磨镀层的制备和性能研究

目的：研究镍钛合金表面耐磨镀层的制备工艺和性能,提高镍钛根管器械的表面硬度和耐磨性。方法：采用直流电镀法在NiTi合金表面制备了Ni—W合金镀层,通过能谱分析和X射线衍射技术（XRD）研究电镀工艺对Ni—W耐磨镀层成分和结构的影响。采用销一盘式摩擦试验机对耐磨Ni—W合金镀层的耐磨性进行测试,通过磨损失重和磨痕形貌观察评价和分析了Ni—W合金镀层的耐磨性和耐磨机理。结果：在NiTi合金表面所制备的Ni—W合金耐磨镀层的W含量在15．2．20．2wt％范围内,且镀层致密,无微观裂纹。Ni—W合金镀层的结构是W在Ni中的固溶体。与Ni—Ti合金基体相比,镀有Ni—W合金镀层的Ni—B合金试样的磨损失重大幅度降低,耐磨性显著提高;Ni—W合金镀层的硬度和耐磨性随镀层中W含量的增加而增大。结论：直流电镀技术对镍钛合金根管器械进行表面改性可显著提高其耐磨忡．     

Experimental impression tray fabricated with a NiTi shape memory alloy plate

A small experimental impression tray was fabricated with a NiTi shape memory alloy plate. After recovery of the shape memory effect, the upper rims of the tray holding the impression were opened to some extent, the resistance during removal of the model from the impression was significantly decreased compared to a commercially available tray and the tray before recovery of the shape memory effect. The pull-out force of the model from the impression was 23.5(0.2)N for the commercially available tray, 23.5(3.9)N for the experimental tray before recovery of the shape memory effect and 14.7(4.0)N after recovery of the shape memory effect (heated for 15 min at 70 degrees C). Therefore the tray should be useful in teeth fracture free modeling.     

Transition temperature range of thermally activated nickel-titanium archwires

Objectives

The shape memory resulting from the superelasticity and thermoelastic effect is the main characteristic of thermally activated NiTi archwires and is closely related to the transition temperature range (TTR). The aim of this study was to evaluate the TTR of thermally activated NiTi archwires commercially available.

Material and Methods

Seven different brands of 0.019"x0.025" thermally activated nickel-titanium archwires were tested as received by differential scanning calorimetry (DSC) over the temperature range from -100°C to 150°C at 10°C/min.

Results

All thermally activated NiTi archwires analyzed presented stage transformation during thermal scanning with final austenitic temperature (Af) ranging from 20.39°C to 45.42°C. Three brands of NiTi archwires presented Af close to the room temperature and, this way, do not present properties of shape memory and pseudoelasticity that are desirable in clinical applications.

Conclusions

The thermally activated NiTi archwires present great variability in the TTR and the elastic parameters of each NiTi archwire should be provided by the manufacturers, to allow achievement of the best clinical performance possible.     

镍钛形状记忆合金在颌面部牵张成骨技术中的研究进展

<正>牵张成骨(distractionosteogenesis,DO)是将持续的外力作用于切骨的新生骨痂或颅面骨缝,保留骨膜及软组织,给予血供,可以使骨组织再生,增加骨组织量,改变骨骼相对位置关系,同时可以相应延长软组织,达到关闭裂隙或矫治缺损的目的[1]。牵张成骨技术的牵张器种类很多,例如王兴等自行研制的内置式颌骨牵张器,崔明军等[2]自行研制的三维骨牵张器等。但用镍钛形状记忆合金牵张器临床应用报道很少,现将其硏究现状做一综述。     

New thermomechanically treated NiTi alloys – a review

In the past 10 years, several proprietary processing procedures for nickel titanium (NiTi) alloy were developed to improve the mechanical properties of NiTi endodontic instruments. Beside specific thermal and mechanical treatments, manufacturers introduced several machining procedures (e.g. twisting, electrical discharge machining), as well as techniques for final surface finishing. NiTi alloys used for endodontic instruments can be subdivided into instruments that mainly contain the austenite phase (austenitic: conventional NiTi, M‐Wire, R‐Phase) and those mainly containing the martensite phase (martensitic: CM Wire, Gold and Blue heat‐treated NiTi). Thermomechanically treated NiTi alloys have been reported to be more flexible with improved cyclic fatigue resistance and greater angle of deflection at failure when compared to conventional NiTi. These enhanced properties may be attributed to a modified phase composition containing varying amounts of R‐phase and martensite. Endodontic instruments made of austenitic alloys possess superelastic properties because of stress‐induced martensite transformation and consequently tend to spring‐back to their original form after deformation. In contrast, the martensitic instruments can easily be deformed due to the reorientation of the martensite variants and show a shape memory effect when heated. The use of martensitic alloy results in more flexible instruments, with an increased cyclic fatigue resistance compared with austenitic alloy.     

Corrosion behavior of shape memory, superelastic, and nonsuperelastic nickel-titanium-based orthodontic wires at various temperatures.

OBJECTIVE: Nickel-titanium orthodontic wires have various temperature-dependent phases. The purpose of this study was to investigate temperature-dependent corrosion characteristics of shape memory, superelastic, and nonsuperelastic orthodontic wires. METHODS: Four orthodontic wires were investigated: 27 and 40 degrees C copper Ni-Ti (superelastic and shape memory, respectively), superelastic Ni-Ti, and nonsuperelastic Nitinol Classic. Differential scanning calorimetry (DSC) was used to confirm phase/temperature behavior of the wires. Sectioned halves of as-received archwires were assessed electrochemically in artificial saliva at 5, 24, 37, and 45 degrees C. Open circuit potential (OCP) was monitored for 2h followed by polarization resistance and cyclic polarization tests. RESULTS: DSC results showed Nitinol was primarily martensitic-stable whereas NiTi, 27 degrees C CuNiTi, and 40 degrees C CuNiTi possessed austenite-finish temperatures of approximately 19, 21, and 38 degrees C. The OCP of the CuNiTi wires was significantly greater than NiTi and Nitinol but no apparent trend in values was apparent with regard to temperature or phases present. Corrosion current density (i(corr)) increased with temperature for all wires, but not all were equally influenced. The two lowest austenite-finish temperature wires (27 degrees C CuNiTi and NiTi) approximately tripled in i(corr) from 37 to 45 degrees C. Greater incidence of pitting was observed in the CuNiTi wires. SIGNIFICANCE: This study showed the corrosion rate of various nickel-titanium wires increase with temperature and different phases present may influence corrosion rate trends.     

Stress corrosion cracking of NiTi in artificial saliva.

OBJECTIVES: This paper aimed to study the mechanism of the cracking of orthodontic NiTi wire. METHODS: Two orthodontic NiTi wires were subjected: (1) optical and scanning electron microscopy (SEM) to observe the fracture surface; (2) energy dispersive X-ray spectroscopy to determine the composition of the surface product; (3) anodic polarization to remove the surface product. Samples of NiTi alloy were subjected to the constant loading test to study the stress corrosion cracking (SCC) behavior of NiTi shape memory alloy in artificial saliva. RESULTS: The results showed that there were three typical areas at the fracture surface of NiTi orthodontic wire. Area '1' was a tool-made notch. Crack initiated from the root of this notch and propagated to form Area '2', which was perpendicular to the wire axis and covered by surface film. This film consisted of Na, K, Cl, P, S and O except Ni and Ti. The cracking process of NiTi alloy under the constant loading test depended on the pH of saliva and applied stress. The crack length was about 262microm, the longest at 300MPa and pH 3.0. SIGNIFICANCE: A tool-made notch in orthodontic NiTi wires can cause SCC. At high stress and low pH, this NiTi alloy was most sensitive to cracking.     

模拟口腔环境下温控型镍钛弓丝力学性能的实验研究

目的研究温控型镍钛弓丝在不同温度人工唾液环境下的力学性能变化,为临床合理、有效地使用温控型镍钛弓丝提供参考。方法利用Instron万能材料力学实验机在25、33、37、60 ℃人工唾液中对4种温控型镍钛弓丝进行改良部分牙弓托槽弯曲实验。将4种温控型镍钛弓丝加载挠曲至3 mm后卸载,绘制弓丝卸载的载荷-挠曲曲线,计算卸载至2.5 mm与0.5 mm之间的卸载刚度,结果采用单因素方差分析法进行统计分析。结果随着温度的升高,4种弓丝的卸载力值均有不同程度的升高;同种弓丝的卸载刚度在25、33、37 ℃时十分接近,而在60 ℃时卸载刚度均有明显增大。结论在本实验条件下,4种温控型镍钛弓丝表现出不同的力学性能,但均表现出临床所需的超弹性与形状记忆效应,也均表现出明显的温度敏感性。