Product Name:nitinol wire surgery
Product Description:
NiTi alloy is a kind of shape memory alloy. Shape memory alloy is a special alloy which can automatically restore its plastic deformation to its original shape at a certain temperature. Its expansion rate is more than 20%, its fatigue life is 1 * 10 to the 7th power, its damping characteristic is 10 times higher than that of ordinary spring, and its corrosion resistance is better than that of the best medical stainless steel at present. Therefore, it can meet the application needs of all kinds of Engineering and medicine, and is a very excellent functional material.
In addition to the unique shape memory function, the shape memory alloy has the excellent characteristics of wear resistance, corrosion resistance, high damping and super elasticity.
?1? Phase transformation and properties of NiTi alloy
As the name suggests, NiTi alloy is a binary alloy composed of nickel and titanium. Due to the change of temperature and mechanical pressure, there are two different crystal phases, namely austenite phase and martensite phase. The transformation order of NiTi alloy during cooling is parent phase (austenite phase) - R phase - martensite phase. R phase is rhombohedral, and austenite is in the state of high temperature (higher than the same temperature at the beginning of austenite) or removal of load (external force removal deactivation), cubic and hard. The shape is stable. The martensite phase is in the state of relatively low temperature (less than MF: that is, the temperature at the end of martensite) or loading (activated by external force). It is hexagonal, ductile, repetitive, unstable and easy to deform.
?2? Special properties of NiTi alloy
1. Shape memory is that when the parent phase of a certain shape is cooled from above Af temperature to below MF temperature to form martensite, the martensite is deformed below MF temperature and heated to below Af temperature. With the reverse phase transformation, the material will automatically restore its shape in the parent phase. In fact, shape memory effect is a heat induced phase transformation process of NiTi alloy.
2. Superelasticity refers to the phenomenon that the strain produced by the specimen under the action of external force is far greater than its elastic limit strain, and the strain can recover automatically when unloading. That is to say, in the parent phase state, due to the effect of external stress, stress-induced martensitic transformation occurs, so the alloy shows different mechanical behavior from ordinary materials, its elastic limit is far greater than ordinary materials, and it no longer abides by Hooke's law. Compared with shape memory properties, hyperelasticity has no thermal participation. In a word, hyperelasticity means that the internal stress does not increase with the increase of strain in a certain deformation range. Hyperelasticity can be divided into linear hyperelasticity and nonlinear hyperelasticity. The relationship between stress and strain in the stress-strain curve of the former is nearly linear. Nonlinear hyperelasticity is the result of stress-induced martensitic transformation and its inverse transformation during loading and unloading in a certain temperature range above AF, so nonlinear hyperelasticity is also called transformation pseudo elasticity. The pseudo elasticity of NiTi alloy is about 8%. The superelasticity of NiTi alloy can be changed with the change of heat treatment conditions; When the temperature is higher than C, the superelasticity begins to decrease.
3. Sensitivity of temperature change in oral cavity: the orthodontic force of stainless steel wire and CoCr alloy orthodontic wire was not affected by the temperature in oral cavity. The orthodontic force of the super elastic Ni Ti alloy orthodontic wire changed with the change of oral temperature. When the deformation is constant. With the increase of temperature, the orthodontic force increased. On the one hand, it can accelerate the movement of the teeth, because the temperature change in the mouth will stimulate the blood flow of the stagnant part of the blood flow caused by the orthodontic device, so that the repair cells can get sufficient nutrition and maintain their vitality and normal function in the process of tooth movement. On the other hand, orthodontists can not accurately control or measure the orthodontic force in the oral environment.
4. Corrosion resistance: studies have shown that the corrosion resistance of NiTi wire is similar to that of stainless steel wire
5. Anti toxicity: NiTi shape memory alloy has special chemical composition, that is, it is a kind of NiTi and other atomic alloy, containing about 50% nickel, which is known to have carcinogenic and cancer promoting effects. In general, titanium oxidation on the surface layer acts as a barrier, which makes Ni Ti alloy have good biocompatibility. The surface layer of TixOy and tixnioy can inhibit the release of Ni.
6. Soft orthodontic force: Currently, the commercially used orthodontic wires include austenitic stainless steel wire, cobalt chromium nickel alloy wire, nickel chromium alloy wire, Australian alloy wire, gold alloy wire and nickel chromium alloy wire ? Titanium alloy wire. The load displacement curves of these orthodontic wires under tensile test and three-point bending test conditions were obtained. The unloading curve platform of NiTi alloy is the lowest and the flattest, which indicates that it can provide the most lasting and soft orthodontic force.
7. Good shock absorption characteristics: the greater the vibration of the arch wire caused by chewing and molars, the greater the damage to the root and periodontal tissue. The results of different arch wire attenuation experiments show that the vibration amplitude of stainless steel wire is larger than that of super elastic nitinol wire, and the initial vibration amplitude of super elastic nitinol wire is only half of that of stainless steel wire. The good vibration and shock absorption characteristics of arch wire are very important for the health of teeth, while the traditional arch wire, such as stainless steel wire, tends to aggravate the root absorption.
?3? Classification of nickel titanium alloy wires Evans and durning classification
1) In 1940, gold bow wire, cobalt chromium alloy wire and stainless steel round wire
2) In 1960, martensite stabilized alloys: most of them were made of NiTi alloy after deformation in martensite state. This kind of arch wire has low rigidity and can produce light orthodontic force. There is no martensitic transformation caused by stress or temperature, so there is no memory effect and hyperelasticity.
3) In 1980, Chinese NiTi alloy and Japanese NiTi alloy archwires were austenitic activated alloys: they are austenitic in any state, and have no martensitic state caused by temperature inside or outside the mouth. The martensitic state can only be caused by stress, which has super elasticity, but has no shape memory function. This kind of arch wire has excellent resilience and low stiffness, and can produce weak orthodontic force,. It is characterized by a constant force from the initial start to the final stage. It has a good effect in the treatment of early tooth irregularity. The disadvantage is that it can't be bent under normal temperature, and it's not easy to weld. If the company is used as the main arch wire, it can often cause unwanted expansion or contraction, and it is difficult to establish a good arrangement of premolars and molars.
4) In 1990, martensite activated NiTi alloy: that is, TTR is lower than or very close to the oral temperature. It exists in a multivariate state at room temperature and is easy to deform. When it is placed in the oral cavity, martensite caused by stress and room temperature transforms to austenite at the same time, that is, it has shape memory function and superelasticity. It is easy to deform at room temperature (about 25 ?) and below, but when it reaches a certain temperature (about 32 ?), it will return to the original preformed shape, showing the characteristics of shape memory and hyperelasticity. Smart brand of Beijing Saint mart technology Co., Ltd. and nitinolha brand of 3M company are typical representative products. Because of this characteristic, the thermally activated NiTi arch wire can be easily shaped and placed in the bracket when it is maintained at room temperature or below. When it is activated by the heat of body temperature in the mouth, it can produce shape restoring force and provide the required strength for orthopedics. Because of the characteristics of "soften when cold, activate when hot" of the heat activated nitinol orthodontic wire, patients can change the orthodontic force with cold and hot water in the mouth under the guidance of doctors, which is more convenient for the correction of the orthodontist and reduces the discomfort in the initial treatment.
5) Graded thermodynamic: the added thermodynamic NiTi alloy: the TTR temperature is higher than the oral temperature, about 40 ?. In this way, when the NiTi arch wire is placed in the oral cavity, it is still multi-element state, the arch wire is relatively soft, and austenite transformation occurs only when the mouth contains hot water. Therefore, the orthodontic force is weaker and can be used as the initial arch wire for adult patients and patients with periodontal disease. The copper nickel titanium wire produced by omcro company and the low hysteresis L-H nickel titanium arch wire produced by Japan have this kind of performance.
?4? Clinical application of nickel titanium alloy wire
1. Because of the super elasticity, shape memory and low stress-strain curve of nitinol archwire, nitinol archwire is usually used as the initial archwire in orthodontic treatment system. In this way, the discomfort of patients will be greatly reduced. Because there are several kinds of straight wire orthodontic techniques, mbt technique recommends the use of 0.016 inch heat activated nickel titanium alloy arch wire (hant wire), demon self-locking bracket technique recommends the use of copper containing heat activated nickel titanium alloy arch wire (phase transition temperature is about 40 ?), 0.016 inch super elastic Ni Ti alloy arch wire is recommended for early alignment in o-pak.
2. Nitinol spring: nitinol push and pull spring is a kind of spring used for orthodontic treatment. It has the characteristics of nitinol super elasticity, and is suitable for orthodontic treatment, opening up the space between teeth and pulling teeth in different directions. A force of about 50 g can be produced by extending the NiTi coil spring by 1 mm. NiTi coil spring has high elastic properties, which can produce soft and stable continuous force under tensile state. The force attenuation is very small, which can produce ideal orthodontic force for clinical tooth movement. Meet the physiological requirements. Compared with the stainless steel wire of the same diameter, the force released by the Ni Ti wire spring is 3.5-4 times lower. Therefore, in the application of orthodontic treatment, patients not only have mild pain, soft and lasting feeling power, but also reduce the return visit time, shorten the course of treatment and improve the curative effect. It is a new excellent mechanical device in orthodontic treatment.
3. L-H arch wire is developed by Dr. soma of Japan and produced by Tommy company" "LH" is named from "low hysteresis", that is to say, when the arch wire is ligated to the bracket, the difference between the stress generated when the arch wire is activated and the stress generated when the arch wire slowly returns to its original state when the tooth is moved is very small. That is, the lag is very small. Soma et al. Compared the stress-strain curves of LH archwire with other nitinol alloy wires, the lag range of L-H archwire is the smallest, which makes the archwire have the advantages of low load and sustained light force. At the same time, the initial inclination of the curve is low, which indicates that the archwire has low stiffness. The lag curves of other types of nitinol alloy archwires show that its stiffness is larger, which obviously shows that L-H archwire has obvious mechanical advantages. Because the content of titanium in Ni Ti composition of LH wire is higher than that of general Ni Ti arch wire, it is called Ti Ni wire, and some experiments have proved that it has strong shock absorption effect. Another feature of the LH nitinol wire is that it can be bent and heated to shape by heat treatment instrument. Therefore, the treatment can be completed from alignment and leveling, opening occlusion to closing gap, and the final stage. As long as the arch wire is taken out at each stage and bent to the required shape, then heat treatment instrument is used to shape it, Strengthen the hardness. At present, L-H arch wire is used in clinic to treat open jaw, partial jaw and reverse jaw. Because of its continuous stability and softness, the effect is better. At the same time, J hook is often used to improve the weakness of soft arch wire. Although MEAW technology has ideal effect for the treatment of maxillary malocclusion, the complicated arch wire bending often makes many doctors shy away. Therefore, some doctors changed to use the rocking chair nitinol arch wire with vertical traction of anterior teeth, which is similar to the mechanical system. Although this has similar effect, they always feel that compared with MEAW, the movement of each individual tooth is not as good as MEAW, because the rocking chair nitinol arch wire is a continuous arch wire, and there is no way to bend it. Therefore, the angle of each tooth is determined by the angle of bracket bonding and the bending degree of arch wire. Unlike MEAW technology, the angle of each tooth has individual adjustment space. Using LH nitinol to bend the rocking chair, and then bending in the mouth with arch wire former, the effect is quite ideal.
Price:85.00
Product Website: http://www.bjtianbometal.com
Company Description
Baoji Tianbo metal materials Co., Ltd.
Address:ShanXiShanXiBaoJiWeibingQingAnBao Village, Bayu Town, High-Tech Zone, Baoji, Shaanxi, China
Descption:Baoji tianbo metal materials co., LTD was founded in 2011, is located in Shaanxi Baoji Chinese titanium valley. The company is specialized in titanium and titanium alloy, refractory and rare non-ferrous metal material by processing, manufacturing, developing and marketing are integrated enterprise. The enterprise fixed assets about 6000000 yuan, annual output of 90 tons, the annual output value of 15 million yuan. We have 1 sets of 3 tons of vacuum furnace, hot and cold rolling machine 1 sets, several CNC lathes, 1 sets of grinding, machining center, and several Testing Instruments. We have 2 professional doctoral students in high quality, 12 professional technicists. The company produces high-quality tantalum, niobium, tungsten, molybdenum, titanium and titanium alloy products, which mainly used in medical equipment, medical implants, aerospace, military, marine, petroleum, machinery manufacturing, electronic chemicals, instruments, vacuum coating etc.. The company is committed to research and development of zirconium -702 , special material sprocessing material and so on, using advanced processing technology to provide various products of high-quality non-ferrous metal processing materials for various industries. Our products standards are GJB, AMS, GB/T, ASTM, ISO and so on.
Registered Capital:500
EmployeeNum:100
Baoji Tianbo metal materials Co., Ltd.
Contact:Winn
Telphone:86-0917-3383198
Fax:86-0917-3380769
Email:baojitianbometal@aliyun.com
Company Website: https://www.bjtianbometal.com

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