| Objective:Preparations of Aluminum and silicon dioxide films on stainless steel and nickel titanium orthodontic wires.To evaluate and compare the effects of Aluminum and silicon dioxide coating on the biocompatibility,corrosion resistance,frictional properties and binding force of orthodontic stainless steel archwires and nickel titanium orthodontic wires.Methods:The physical vapor deposition-magnetron sputtering was used to prepare Al-SiO2 composite coatings on the surface of 0.016*0.022 stainless steel arch wires,0.016*0.022 nickel-titanium arch wires,orthodontic stainless steel and nickel-titanium planar sample surfaces,in which 0.016*0.022 uncoated stainless steel arch wire,0.016*0.022 uncoated nickel-titanium arch wire,orthodontic stainless steel planar sample,and nickel-titanium planar sample were used as the control group;correspondingly,0.016*0.022 Al-SiO2 coated stainless steel arch wire,0.016*0.022 Al-SiO2 coated NiTi arch wire,Al-SiO2 coated orthodontic stainless steel planar sample,Al-SiO2 coated NiTi planar sample were used as experimental groups.Scanning electron microscope（SEM）and energy dispersive spectrometer（EDS）were used to observe the surface and cross-section morphology of the coating and to detect the elemental composition of the coating.Investigating the biocompatibility,corrosion resistance,friction and coating adhesion of Al-SiO2 composite coatings through cytotoxicity experiments,electrochemical experiments,friction and wear experiments,and scratch tests.Results:1.The surface of the Al-SiO2 coating was uniform and smooth;the interface between the coating and the substrate was in close contact,and the bonding was having a continuous interface without any interfacial defects.2.Cytotoxicity experiments showed that there was no statisticaly significant difference between the experimental group,the control group,and the blank group by statistical analysis of OD values at different time points（days 1,3,5,and 7）;according to the cytotoxicity evaluation criteria,Al-SiO2 coated stainless steel arch wire and Al-SiO2 coated nickel-titanium arch wire were not cytotoxic.3.Electrochemical experiments found that the corrosion current density of the Al-SiO2coating experimental group was reduced compared with the control group,and The corrosion current of the nickel-titanium control group,the nickel-titanium experimental group,the stainless steel control group,and the stainless steel experimental group were23.72uA/cm2,1.21uA/cm2,0.22uA/cm2,0.06uA/cm2,respectively.The Al-SiO2coating improved the corrosion resistance of the arch wire.4.Friction and wear experiments showed that the friction coefficient of the experimental group was reduced compared with the control group,The friction coefficients of the nickel-titanium control group,the nickel-titanium experimental group,the stainless steel control group,and the stainless steel experimental group were 0.68,0.46,0.58,and 0.45,respectively.And the Al-SiO2 coating had better corrosion resistance than the control group.5.The scratch test showed that the bonding strength of the nickel-titanium coating of Al-SiO2 was 15.07N;the bonding strength of Al-Si O2 coating stainless steel was 8.3N.The Al-SiO2 coating was stable and had a stronger binding force.Conclusion:Al-SiO2 coating was successfully prepared on the surface of nickel-titanium and stainless steel archwires by magnetron sputtering and it had been proved to have good biological safety and physical properties. |
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