Nitinol alloy superior performance
The special properties of nitinol generally have the following points:
Shape memory: shape memory is the shape of the mother phase from Af below the temperature below the Mf temperature below the formation of martensite, the martensite below the Mf temperature deformation, heated to Af below the temperature, with the reverse phase change, The material automatically recovers its shape in the mother phase. In fact, the shape memory effect is a heat-induced phase transition of nitinol.
Super-elastic: The so-called super-elastic refers to the specimen under the action of external force is much greater than the elastic strain limit strain, unloaded strain can be automatically restored phenomenon. That is, in the state of the mother phase, stress-induced martensitic transformation occurs due to the effect of external stress, so that the alloy exhibits different mechanical behavior from common materials, its elastic limit is far greater than ordinary materials, and no longer observes tiger Law.
Corrosion resistance: Some studies have shown that the corrosion resistance of nickel titanium wire with stainless steel wire similar.
Oral sensitivity to temperature changes: stainless steel wire and CoCr alloy Orthodontic silk orthodontic force almost no oral temperature effects. Orthodontic Ni-Ti alloy orthodontic wire orthodontic power with oral temperature changes. When the deformation is a certain amount of time. Temperature increases, orthopedic increased. On the one hand, it can accelerate the movement of the teeth because the temperature changes in the mouth can stimulate blood flow in the stagnant blood flow site causing the capillary sluggishness due to the treatment device, so that the repaired cells are fully nourished during tooth movement, Maintain its vitality and normal function. On the other hand, orthodontists are not in a position to precisely control or measure orthodontics in the oral environment.
Toxicity: Nickel-Titanium shape memory alloy special chemical composition, that is, this is a nickel titanium and other atomic alloys containing about 50% nickel, and nickel is deemed to have carcinogenic and cancer-promoting effects. Under normal circumstances, the surface layer of titanium oxide serves as a barrier to the Ni-Ti alloy has good biocompatibility. The surface layer of TiXOy and TixNiOy can inhibit the release of Ni.
Soft orthodontic power: Orthodontic wires currently used commercially include austenitic stainless steel wire, cobalt-chromium-nickel alloy wire, nickel-chromium alloy wire, Australia alloy wire, gold alloy wire and nitinol wire. Load-displacement curves of these orthodontic strand under tensile and three-point bending test conditions. NiTi unloading curve platform minimum and maximum level, indicating that it can provide the most lasting soft orthodontic.
Good shock absorption characteristics: Due to chew and bruxism on the wire caused by the greater vibration, the greater damage to the root and periodontal tissue. Results of different bow wire attenuation experiments show that the amplitude of vibration of stainless steel wire is larger than that of surrealistic NiTi wire. The initial vibration amplitude of surrealistic NiTi wire is only half that of stainless steel wire. Excellent vibration and damping characteristics Tooth health is very important, while the traditional arch wire such as stainless steel wire, tend to increase the root absorption.
