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Objective @#To explore the influence and mechanism of different types of proteins on the corrosion resistance of alloy to provide a reference for the safe application and surface modification of nickel-titanium (Ni-Ti) and stainless steel bow wires in the clinic.@*Methods@#The effects of fibrinogen, IgG and mucin on the electrochemical corrosion resistance of Ni-Ti and stainless steel arch wires were tested by the potentiodynamic polarization method, and the repair ability of passive films on surfaces treated with the three proteins were tested by the cyclic polarization method. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used to determine the types of corrosion products, and the surface morphology after corrosion was analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM).@*Results @#The addition of fibrinogen, IgG or mucin to an alloy has different effects on its corrosion resistance. Adding protein can reduce the corrosion resistance of stainless steel alloys and slow the corrosion process of Ni-Ti alloys. The addition of mucin can improve the corrosion resistance of Ni-Ti alloy and the repair ability of passive film. Compared with mucin and IgG, fibrinogen can reduce the pitting resistance of Ni-Ti and stainless steel alloys.@*Conclusion @#Different types of proteins interact differently with the arch wire, form different deposition morphologies on the surface, and participate differently in the corrosion process of the alloy.
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Nonextraction camouflage treatment in mild Class III malocclusion is achieved by backward movement of the lower dentition and forward movement of the upper dentition. Many camouflage treatment modalities have been used for distal tipping and distal movement of mandibular posterior teeth. The amount of distal movement of mandibular dentition can be improved in cases of severe crowding, even without the patient's cooperation, by using miniscrews for anchorage. However, miniscrew insertion may be unsuccessful, and it may contact the adjacent root because of the distal movement of dentition. Distal tipping of mandibular dentition can be achieved using multiloop edgewise archwires and intermaxillary elastics. However, the complexity of this wire design causes discomfort to patients. Recently, a new treatment using improved superelastic NiTi wires (ISWs) and intermaxillary elastics has been introduced. ISWs can deliver orthodontic force more effectively, and their use with molar tip-back treatment has several advantages-this approach is effective, simple, and easy to use and reduces patient discomfort. The aim of this study was to report a case of camouflage treatment using ISW with tip-back and intermaxillary elastics for distal tipping of mandibular posterior dentition and to evaluate the effectiveness of this treatment in a clinical setting.
Subject(s)
Humans , Crowding , Dentition , Malocclusion , Molar , ToothABSTRACT
ObjectiveTo analyze the clinical effect of internal fixation with grip-type of Ni-Ti alloy plate in treatment of multiple ribs fractures.MethodsClinical data of 50 patients with multiple ribs fractures treated by internal fixation t with grip-type of Ni-Ti alloy plate were retrospectively analyzed.ResultsThe chest pain alleviated,the shape of bony thorax recovered, paradoxical respiration vanished, and dyspnea relieved significantly in all cases after operation.Two months after operation, chest X-ray indicated healed fractures, internal fixation without loosening and breaking off, no chest deformity in all patients.Followed up 2 to 14 months,an average of 9 months,and no complication was found.ConclusionThe internal fixation with grip-type of Ni-Ti alloy plate in treatment of multiple ribs fractures was simple ,convenient,less invasive ,good tissue compatibility, stable fixation, less complications, and clinical results were satisfactory.
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@#ObjectiveTo investigate the effect of nickel-titanium(Ni-Ti) shape memory alloy embracing internal fixer on oblique or spiral fracture.Methods23 cases with spiral or oblique fracture accepted internal fixation with Ni-Ti shape memory alloy embracing.The time of bone healing,articular function,the appearance and function of the wound extremity were evaluated after 9～34 months follow-up.ResultsAll fractures healed in 4～16 weeks after operation.None infection,nonunion,embracing emersion or break had been found. The fine rate was 91.3%.ConclusionThe effect of Ni-Ti shape memory alloy embracing internal fixer on long spiral or long oblique fracture is satisfactory.
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To estimate the characteristics of Korean Ni-Ti alloy orthodontic wire, this study investigated compositions, tensile properties, bending properties, heat treatment effects, and ion releasing degrees, and compared these characteristics to those of the imported Ni-Ti alloy wire. The results obtained are as follows; 1. Ti and Ni elements in ORTHOLLOY were in a range showing superelasticity, and there was a little difference in the Ni and Ti contents of ORTHOLLOY as compared with those of SENTALLOY. 2. The results of the tensile test concerning ORTHOLLOY exhibited a superelastic effect, indicating an area of a definite amount of stress in spite of the changes in the range from 2% to 8% in the strain rate. 3. ORTHOLLOY presented higher load values than SENTALLOY in the same deflection values when the wire was tested in three-point bending. A load range displaying a superelastic effect was 80-100g, 140-180g, and l50-200g respectively, in wire diameters of 0.014", 0.016", and 0.018". 4. By heat treatments at 400degreesC and at 500degreesC, a load range showing the effect of superelasticity was lessened by the duration of the heat treatment time. The superelastic effect was destroyed as a result of the 10 minutes heat treatment at 600degreesC. 5. The quantity of the Ni ion released from ORTHOLLOY, tended to be greater than the amount of released Ni ion in SENTALLOY. The Co ion released was very little(<0.01ppm) in SENTALLOY and ORTHOLLOY irrespective of the lapse of time. Released Ni ions on the 1st day were at the maximum, and the releasing rate showed plateaus after three days. 6. The surface morphology of SENTALLOY was relatively regular irrespective of the lapse of time, and the corrosion tendency was not observed. However, the surface morphology of ORTHOLLOY was rather irregular and showed pitting corrosion after immersion.