The Effects Of Different Nickel-titanium Arch Wires In Orthodontic Treatment: A Systematic Review

Objective: To evaluate the effects of different nickel-titanium arch wires in orthodontic treatment,including the initial alignment efficiency,time to alignment,pain perception and root resorption.Materials and Methods: We included randomized controlled trials(RCTs)of different nickel-titanium arch wires in orthodontic treatment.Electronic and manual unrestricted searches were conducted in Pub Med,Web of science,Cochrane Central Register of Controlled Trials Library(CENTRAL),Scopus,CNKI,CBM and Wanfang database.Two review authors were responsible for study selection.We resolved disagreements by discussion or by another reviewer.We contacted corresponding authors of included studies to obtain missing information.Meta-analysis was performed using Rev Man 5.3 software.Results: 15 RCTs with 814 participants provided data for this review.We judged 2 studies to be high risk of bias,and 8 to be low risk of bias,5 to be unclear.The review assessed four comparisons.1.Superelastic nickel-titanium versus heat-activated nickel-titanium arch wires.There were 8 studies in this group.The results showed that there was no significant difference in the initial alignment efficiency,time to alignment and pain perception.1study showed that the root resorption of superelastic nickel-titanium arch wire was more obvious than that of heat-activated nickel-titanium arch wire at 8 weeks of treatment.2.Superelastic nickel-titanium versus conventional nickel-titanium arch wires.There were 4 studies in this group.The results showed that there was no significant difference in the initial alignment efficiency,time to alignment and pain perception between the two groups.3.Heat-activated nickel-titanium versus conventional nickel-titanium arch wires.There were 6 studies in this group.The results showed that there was no significant difference in the initial alignment efficiency,time to alignment,pain perception and root resorption between the two groups.4.Single-strand superelastic nickel-titanium versus coaxial superelastic nickel-titanium arch wires.There were only 2 studies in this group,but it was not appropriate to undertake a meta-analysis of the data.There is insufficient evidence from these studies to determine whether there is a difference between single-strand superelastic nickel-titanium and coaxial superelastic nickel-titanium arch wires.Pain was not measured.Conclusions: 1.The results showed that there was no significant difference in alignment efficiency and pain perception between conventional nickel-titanium,superelastic nickel-titanium and heat-activated nickel-titanium arch wires.2.The root resorption of superelastic nickel-titanium arch wires was more obvious than that of heat-activated nickel-titanium arch wires at the early stage of orthodontic treatment.3.At present,there are still few studies on the treatment efficiency of different nickel-titanium arch wires.It is still necessary to further explore the effect of different nickel-titanium arch wires in orthodontic treatment.