Evaluation of the surface properties of modified Ni-Ti arch wires

Abstract

Aim: Materials used in orthodontic treatment can cause corrosion and metal ion release to the mouth. This study was aimed to examine the changes in the friction coefficients and corrosion resistance of the modified Ni-Ti arch wires.
 Methodology: Our sample consisted of 16 Ni-Ti arch wires (0.016 × 0.022 inches). Coating bathes involving Ni-Ti, Ni-Ti-Mo, and Ni-Ti-Cr were prepared for arch wires coating. New surfaces were analyzed by SEM, and the crystallographic structure was determined by X-rays. The friction coefficient of the coated wires was determined by nanoindentation. Artificial saliva was prepared as a corrosive condition. Impedance measurements were performed with an electrochemical analyzer. The AC impedance spectroscopy measurements were performed after four hours, seven, 15, 30, 45, and 60 days.
 Results: All groups were more resistant than the control group (-447 mV) [group 1 (-388 mV), group 2 (-328 mV), group 3 (-327 mV), group 4 (-427 mV), group 5 (-395 mV), group 6 (-366 mV), and group 7 (-380 mV)]. Friction coefficients of group 5 (0.252) and group 6 (0.265) were observed to be lower than those of the control group (0.288).
 Conclusion: In the results of our study, it was shown that the surface properties of Ni-Ti wires could be electrochemically improved. The coated wires (group 5 and group 6) had a remarkable corrosion resistance and reduced friction. The protocols that we used should help provide better-quality surfaces.
 
 How to cite this article: Özyılmaz AT, Bilgiç Zortuk F, Yılmaz H. Evaluation of the surface properties of modified ni-ti arch wires. Int Dent Res 2021;11(Suppl.1):167-176. https://doi.org/10.5577/intdentres.2021.vol11.suppl1.25
 
 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Functional Surface Coatings on Orthodontic Appliances: Reviews of Friction Reduction, Antibacterial Properties, and Corrosion Resistance

“…The current trend tends to combine TiN with other application materials. TiN-derived coating materials such as titanium carbonitride (TiCN) [ 31 , 32 ], multilayer titanium nitride/titanium (TiN/Ti) [ 33 ], and nickel-titanium-molybdenum (Ni-Ti-Mo) composite coatings [ 57 ] not only have a more exact friction reduction effect than TiN, but are also more beneficial to clinical application due to other advantages.…”

“…The standard NiTi coating does not reduce friction, and the addition of different concentrations of chromium (Cr) to the standard coating material to form a nickel-titanium-chromium (Ni-Ti-Cr) coating also does not reduce friction. [ 57 ]…”

“…In summary, the trends of Ti compound coatings are nitriding [ 30 ], incorporation of other metal ions [ 57 ], multi-layered materials [ 33 ], and low-thickness materials [ 64 ]. Most of these are still some distance away from being applied in clinical practice, but attempts can be made to find the most suitable preparation conditions and methods to obtain coating materials with satisfactory properties in all respects.…”