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.
Highlights
Tooth movement is an essential part of orthodontic treatment
In our previous study we showed that zinc oxide nanoparticles (ZnO) nanoparticles coating of stainless steel archwires decreased friction during sliding within stainless steel brackets.20In another research, we tried to decrease friction between stainless steel wires and ceramic brackets by depositing ZnO nanoparticles on the wires but we found no significant differences between coated and uncoated wires.21To the best of our knowledge, this is the first timethe porcelain brackets are coated with ZnO nanoparticles for decreasing frictional forces during sliding mechanics
In the present study the mean of frictional forces was maximal in the the ZZ and minimum in the OZ groups, with no significant difference between the ZO and OO groups
Summary
Tooth movement is an essential part of orthodontic treatment. Sliding the tooth on an orthodontic wire is one of the techniques in this context, withJODDD, Vol 10, No 2 Spring 2016 advantages including a decrease in chair time, patient comfort and 3-dimensional control of tooth movements.[1]. Subsequent to application of forces on the tooth, tipping movements begin, creating an angle between the bracket and the wire. 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). In this in vitro study, we evaluated a combination of 120 samples of 0.019×0.025 stainless steel (SS) orthodontic wires and 22 mil system edgewise porcelain brackets with and without spherical zinc oxide nanoparticles. 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.
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