The effect of ZnO nanoparticle coating on the frictionalresistance between orthodontic wires and ceramic brackets

Abstract

Background. Any decrease in friction between orthodontic wire and bracket can accelerate tooth movement in the sliding technique and result in better control of anchorage. This study was carried out to evaluate frictional forces by coating orthodontic wires and porcelain brackets with zinc oxide nanoparticles (ZnO).Methods. In this in vitro study, we evaluated a combination of 120 samples of 0.019×0.025 stainless steel (SS) orthodonticwires and 22 mil system edgewise porcelain brackets with and without spherical zinc oxide nanoparticles. Spherical ZnOnanoparticles were deposited on wires and brackets by immersing them in ethanol solution and SEM (scanning electronmicroscope) evaluation confirmed the presence of the ZnO coating. The frictional forces were calculated between the wiresand brackets in four groups: group ZZ (coated wire and bracket), group OO (uncoated wire and bracket), group ZO (coatedwire and uncoated bracket) and group OZ (uncoated wire and coated bracket). Kolmogorov-Smirnov, Mann-Whitney andKruskal-Wallis tests were used for data analysis.Results. The frictional force in ZZ (3.07±0.4 N) was the highest (P <0.05), and OZ (2.18±0.5 N) had the lowest amount of friction (P <0.05) among the groups. There was no significant difference in frictional forces between the ZO and OO groups (2.65±0.2 and 2.70±0.2 N, respectively).Conclusion. Coating of porcelain bracket surfaces with ZnO nanoparticles can decrease friction in the sliding technique,and wire coating combined with bracket coating is not recommended due to its effect on friction.

Evaluation of zinc-oxide nanocoating on the characteristics and antibacterial behavior of nickel-titanium alloy

“…These results agree with Kachoei et al 14 Scanning electron microscope images showed spherical ZnO nanoparticles with particle size ranging from 25 to 30 nm. Behroozian et al 19 used SEM technique to evaluate surface pattern of ZnO nanoparticles deposition and showed the presence of spherically shaped ZnO nanoparticles on the wire. Kachoei et al 20 confirmed a uniform coating of spherical shaped ZnO nanoparticles on stainless steel wires with narrow size distribution ranging from 40 to 45 nm.…”

“…The frictional force was recorded as 1.227 N in the coated wires and 1.642 N for the non-coated wires. Also, Behroozian et al 19 studied the ZnO nanoparticles coating effect on the frictional resistance between ceramic brackets and orthodontic wires, and reported that the ZnO nanoparticles deposition had significantly decreased the frictional forces between brackets and stainless steel wires.…”

Nanomaterials Application in Orthodontics

“…It is important to underline, that ZnO and CuO coated brackets have been observed with better antimi-crobial characteristics on Streptococcus mutans than when the brackets were coated with CuO nanoparticles alone [ 77 ]. Kachoei et al [ 78 ], Behroozian et al [ 79 ] and Goto et al [ 80 ] proved, that following ZnO nanoparticle coating, the frictional forces be-tween archwires and brackets significantly decreased. Because of that effect, these na-noparticles offer new opportunities in overcoming the unwanted friction forces, better anchorage control, and reduced risk of resorption.…”

Evaluating the Mechanical Properties of Zinc-Coated Stainless Steel Orthodontic Wires Using Physical Vapor Deposition

“…Furthermore, reduced frictional forces between wires and brackets have been previously reported which might contribute to a significant reduction in friction during tooth movement [ 15 , 16 ].…”