Classification of Medical Nickel-Titanium Guidewires

Classification of Medical Nickel-Titanium Guidewires

Martensitic-stabilized alloys are predominantly nickel-titanium alloys that have undergone martensitic transformation. These archwires exhibit low stiffness and gentle correction forces. Since there is no stress- or temperature-induced martensitic phase transformation, they lack both the shape-memory effect and superelasticity.

 1980 China's Nitinol and Japan's Nitinol arch wires are austenite-activated alloys. : It maintains an austenitic state under all conditions, ensuring that neither intraoral nor extraoral environments trigger temperature-induced martensitic transformation—such transformation can only be induced by stress. These wires exhibit superelasticity but lack shape-memory functionality. While possessing excellent resilience and relatively low stiffness, they generate only mild corrective forces. Notably, they deliver a consistent force throughout both the initial and final stages of treatment, making them particularly effective for addressing early-stage dental irregularities. However, a key limitation is their inability to be easily bent or shaped at room temperature, and they are also challenging to weld. When used as the primary archwire in clinical practice, this can often lead to unintended arch expansion or contraction, making it difficult to achieve optimal alignment of premolars and molars.

Sensitivity of Medical Nitinol Guidewires to Intraoral Temperature Changes : Stainless steel wire and CoCr Orthodontic forces generated by alloy wires remain unaffected by oral temperatures. In contrast, the orthodontic force of highly elastic nickel-titanium wires fluctuates in response to changes in oral temperature—specifically, when deformation remains constant. As the temperature rises, the corrective power increases, which can accelerate tooth movement. This is because temperature variations within the mouth stimulate blood flow in areas where treatment appliances have temporarily halted circulation, helping to restore proper nutrient supply to repair cells during tooth movement and ensuring their vitality and optimal function. On the other hand, orthodontists are unable to precisely control or measure the corrective forces acting within the oral environment.

Medical Nickel-Titanium Guidewire Corrosion Resistance Performance : Studies have shown that the corrosion resistance of nickel-titanium wires is similar to that of stainless steel wires.

Medical Nickel-Titanium Guidewire with Antitoxicity : Nickel-titanium shape-memory alloys have a unique chemical composition—they are nickel-titanium alloys with nearly equal atomic ratios, containing approximately nickel. 50% , and nickel is already known to have carcinogenic and cancer-promoting effects. Overall, the surface titanium oxide layer acts as a barrier, enabling Ni-Ti The alloy exhibits excellent biocompatibility. The surface layer contains TiXOy And TixNiOy Can inhibit You The release.

Soft Orthotic Force : Currently available commercial dental orthodontic wires include austenitic stainless steel wire, cobalt-chromium-nickel alloy wire, nickel-chromium alloy wire, Australian alloy wire, gold alloy wire, and ? Titanium alloy wire. Load under tensile and three-point bending test conditions for orthodontic corrective wires - Displacement curve. Nitinol exhibits the lowest and most stable unloading curve platform, indicating that nitinol can deliver consistent, gentle corrective forces over time.

Excellent shock-absorbing properties : The greater the vibration generated by arch wires due to chewing and nighttime teeth grinding, the more significant the damage to tooth roots and periodontal tissues. Through various damping experiments, researchers found that stainless steel arch wires exhibit larger vibration amplitudes compared to superelastic nickel-titanium wires. Notably, the initial vibration amplitude of superelastic nickel-titanium wires is only half that of stainless steel wires. These wires' excellent vibration-damping properties are crucial for maintaining dental health, whereas conventional arch wires like stainless steel tend to accelerate root resorption.