Shape Remembering Metal nitinol wire

Nitinol wire classification
1) In 1940, gold bow wire, cobalt chromium alloy wire and stainless steel round wire
2) In 1960, the martensitic stabilizing alloy: mostly made of nickel-titanium alloy deformed in the martensite state. This kind of arch wire has low rigidity, which can produce lighter correction power. There is no martensitic transformation caused by stress or temperature, so there is no memory effect and superelasticity.
3) In 1980, Chinese nickel-titanium alloy and Japanese nickel-titanium alloy archwires were austenite activated alloys: that is, they exhibited an austenite state in any state, and they did not have temperature-induced martensitic inside and outside the mouth. Body state, martensite state can only be caused by stress, has super elasticity, but does not have shape memory function. This kind of arch wire has excellent resilience and low stiffness, and can produce weaker correction force. The big feature is that from the initial start to the final stage, the force it generates continues to be constant, and the effect is better when the teeth are not neatly treated early. The point of removal is that it cannot be bent at room temperature and is not easy to weld. If the company is used as the main arch wire, it can often cause undesirable expansion or contraction, and it is difficult to establish a good premolar and molar arrangement.
4) In 1990, martensite activated nickel-titanium alloy: TTR was lower than the oral temperature or very close to the oral temperature, existed in a multiple state at room temperature, easy to deform, and caused by stress when placed in the oral cavity At room temperature, martensite transforms into austenite at the same time, that is, there is shape memory function and super elasticity. It is easy to deform at normal temperature (about 25oC) and below, and when it reaches a certain temperature (about 32oC), it will return to the original pre-formed shape, showing shape memory plus super-elastic properties. Beijing Smart Technology Co., Ltd. Smart brand and 3M company Nitinol HA brand are typical representative products. Because of this characteristic, the thermally activated nickel-titanium arch wire can be easily formed by maintaining it at room temperature and below, and placed in the bracket. When activated by the temperature and heat of the receptor in the mouth, it can produce The shape restoring force provides the required strength for orthopedics. Because the heat activated nickel-titanium orthopedic wire has the characteristics of “softening in the cold, and becoming more elastic when heated”, the patient can use the cold and hot water in the mouth to change the correction power under the guidance of the doctor. It facilitates the correction of the corrector and reduces the discomfort of the initial correction.
5) Graded thermodynamic: Increased thermodynamic nickel-titanium alloy: The TTR temperature is higher than the oral cavity temperature, about 40oC, so that when the nickel-titanium arch wire is placed in the oral cavity, it is still in a multiple state, the arch wire is relatively soft, The austenite phase changes only when it contains hot water. Therefore, the correction power is weaker and can be used as the initial arch wire for adult patients and periodontal disease patients. Omcro’s copper-containing nickel-titanium wire and Japan’s low-lag L-H nickel-titanium arch wire have this kind of performance