Application Of Nitinol Wire in Medical Treatment
Special properties of Nitinol:
1. Shape memory characteristics: When the parent phase of a certain shape is cooled from Af temperature above to Mf temperature below the martensite, the martensite is deformed at the temperature below Mf, and heated to Af temperature below, with the reverse phase transition, the material will automatically restore its shape in the parent phase. In fact, shape memory effect is a heat-induced phase transition process of Nitinol alloy.
2. Superelasticity: refers to the specimen under the action of external forces to produce much greater than the elastic limit of the strain, the strain can be automatically recovered during unloading phenomenon.
3. Sensitivity to changes in oral temperature: the correcting force of stainless steel wire and Co,Cr alloy dental orthopedic wire is basically not affected by oral temperature. The correcting force of the superelastic Nitinol tooth orthotic wire changes with the change of oral temperature. When the amount of deformation is certain. As the temperature increases, the healing power increases.
4. Corrosion resistance: the corrosion resistance of nickel titanium wire is similar to that of stainless steel wire
5. Anti-toxicity: The special chemical composition of nickel-titanium shape memory alloy, that is, this is a nickel-titanium and other atomic alloy, containing about 50% nickel, and nickel is known to have carcinogenic and cancer-promoting effects. In general, surface layer titanium oxidation acts as a barrier, making Ni-Ti alloys have good biocompatibility. TiXOy and TixNiOy in the surface layer can inhibit the release of Ni.
6. Good shock absorption characteristics: the greater the vibration caused by chewing and night grinding to the arch wire, the greater the damage to the root and periodontal tissue. Through the results of different bow wire attenuation experiments, it is found that the vibration amplitude of stainless steel wire is larger than that of super elastic nickel titanium wire, and the initial vibration amplitude of super elastic nickel titanium wire is only half of that of stainless steel wire. Good vibration and shock absorption characteristics of bow wire are very important for the health of teeth, and traditional bow wire such as stainless steel wire has a tendency to increase tooth root absorption.
Clinical application of Nitinol wire:
1. Early alignment for patients' dentition.Due to the superelasticity and shape memory properties of nickel-titanium alloy bow wire as well as low stress-strain curve, nickel-titanium alloy bow wire is currently routinely used as the first bow wire to be incorporated into the correction system in clinical practice, thus greatly reducing the discomfort of patients.
2. nickel-titanium spring: nickel-titanium push spring and pull spring is a spring for dental orthodontics, with nickel-titanium superelasticity, suitable for orthodontic treatment to open up the gap between the teeth and pull teeth in different directions.
