The Anti-adhesion Study Of Laser Welding Composite Arch Wire With Copper Interlayer Between NiTi And Stainless Steel To Streptococcus Mutans

Orthodontic arch wire materials commonly used in the clinicaltreatment of orthodontic are mainly including nickel titanium arch wire,stainless steel wire and β-titanium wires. Arch wire properties and toothmovement effect are closely related, so as to meet a variety of orthodonticclinical requirements, performance of scholars of orthodontic arch wirehave been improved research. Composite archwire (CAW) is formed bysolder connection of nickel-titanium and stainless steel arch wire. CAWcombines the advantages of the individual material to correct malposedteeth whilst maintain the stability of anchored teeth.CAW provideanchorge for canine teeth in the stage of alignment and leveling anteriorteeth, so CAW can shorten the treatment course about six months in teethextracted for orthodontic cases. Hongmei Li etcl improved weldingconnection strength of nickel titanium clad stainless steel arch wires bylaser beam welding with copper intermediate layer.The materialmechanical performance is better than traditional composite arch wire.Before clinical using this new material has been tested the physical andchemical properties, mechanical properties, corrosion resistance and cell toxicity, studies show that in vitro biological safety performance of thecomposite arch wire is better, in addition in simulated oral environment indifferent pH, chlorine, fluorine, protein under the condition of compositearch wire still has corrosion resistance better. However, according to theresearch of the composite archwire bacteria in vitro have not beenreported.Purpose: This study proposed by co-culture of composite archwire andStreptococcus mutans, and nickel titanium arch wire, stainless steel wireand wire by contrast, acridine orange fluorescent staining and scanningelectron microscope, study its antibacterial and anti adhesion properties.Methods:Selecting Nickel titanium arch wires0.483mm×0.635mm(Smart, Beijing); stainless steel archwire (3M, America); laser weldingwith copper intermediate layer of nickel titanium alloy and stainless steelcomposite archwire (Composite Arch wire, CAW, provide materialsCollege of Jilin University); copper (Ningbo Wei Kang New Material Co.Ltd) backup after disinfection. The experiment consists of a fluorescentmicroscope and scanning electron microscope observation. Experimentalgroups are placed in the concentration of Streptococcus mutans bacterialiquid of1×109CFU/L, at80%N2，10%CO2，10%H2，37degrees C after48h culture，and the backup samples after disinfection are control groups.Through fluorescent microscope and scanning electron microscope observation，counting quantity of living bacterium adhesion to the surfaceof these arch wires.Result:Copper wire, CAW solder joint showed the red fluorescence, andnickel titanium arch wire, stainless steel wire and CAW nickel titaniumparts, stainless steel parts are black through fluorescent microscopeobservation in control groups. Copper wire, CAW solder joint showed thered fluorescence, and nickel titanium arch wire, stainless steel wire andCAW nickel titanium parts, stainless steel parts are green fluorescence ofbacterial adhesion area through fluorescent microscope observation inexperimental groups. Scanning electron microscopic observation of CAWwelded zone continuous by nickel titanium arch wires, stainless steel wire,copper interlayer showed connecting well. Nickel titanium side, stainlesssteel side and nickel titanium arch wires, stainless steel wire and copperwire, CAW with copper interlayer surfaces are all in mess and roughnessand can be seen scattered in the polished texture pore in experimentalgroups. Scanning electron microscopic nickel titanium arch wires,stainless steel wire and CAW nickel titanium parts, stainless steel partssurface has a large number of bacteria adhesion, patchy distribution;copper wire almost no bacterial adhesion. CAW welded zone surfaceadhesion of bacteria is few, the number was significantly less than that ofnickel titanium arch wires, stainless steel wire and CAW nickel titaniumparts, stainless steel parts, were scattered, and some bacteria dissolved, broken. With the welding point extends to nickel titanium side andstainless steel side, the amount of bacteria increased adhesion andagglomeration, like in the scratch, ravines are.Scanning electronmicroscopy counting results show that the bacterial adhesion of CAWsolder joint and copper wire is less than the amount of nickel titaniumarch wire,stainless steel wire and CAW nickel titanium parts, stainlesssteel parts statistically significant difference (P <0.01); The bacterialadhesion of nickel titanium arch wire and CAW nickel titanium parts isless than the amount of stainless steel and CAW stainless steel parts,statistically significant difference (P <0.01).Conclusion: The copper inter layer of CAW compared with CAWnickel titanium parts and CAW stainless steel wire parts has a degree ofanti adhesion effect on Streptococcus mutans. The bacterial adhesion ofCAW nickel titanium parts is less than CAW stainless steel wireparts. The bacterial adhesion of nickel titanium wire is less thanstainless steel wire.