Shamohammadi Milad, Hormozi Elham, Moradinezhad Mehrnaz, Moradi Mina, Skini Masoumeh, Rakhshan Vahid
Department of Orthodontics, School of Dentistry, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Department of Orthodontics, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
Int Orthod. 2019 Mar;17(1):60-72. doi: 10.1016/j.ortho.2019.01.016. Epub 2019 Feb 15.
Surface topography is a crucial factor in bracket sliding mechanics. Literature on surface roughness of aesthetic archwires is scarce, and there is no study on surface topography of such archwires affected by any sterilization methods. The aim of this study was to compare the surface topography of plain nickel-titanium (NiTi) versus as-received aesthetic coated NiTi wires versus aesthetic wires sterilized by autoclaving or glutaraldehyde immersion.
This in vitro study was performed on 80 atomic force microscopy (AFM) observations, 160 profilometry observations, and 40 scanning electron microscopy (SEM) images from rectangular wires of the brands 'American Orthodontics, Ortho Organizers, SIA, and Gestenco'. AFM consisted of 8 subgroups of NiTi orthodontic wires, consisting of 4 subgroups of 4 brands of coated orthodontic wires and 4 subgroups of 4 brands of uncoated wires from the same brands. Profilometry consisted of 16 subgroups of NiTi orthodontic wires, consisting of 4 subgroups of 4 brands of coated orthodontic wires and 12 subgroups of 4 brands of uncoated wires from the same brands (4 as-received wire subgroups, 4 autoclaved, and 4 cold-sterilized subgroups). Scanning electron microscopy (SEM) and AFM images were subjectively evaluated. AFM and profilometry data were analysed statistically (α=0.05).
Overall, the difference between surface roughness parameters of coated versus uncoated archwires was not significant (P>0.05). However, surface roughness of brands differed significantly. Mann-Whitney did not show any significant differences between sterilized wires (both sterilization methods together as one group) and unsterilized wires (both unsterilized coated and uncoated as one group) (P>0.460). After excluding plain uncoated NiTi group, the coated wires in 3 sterilization groups (no sterilization, autoclaving, glutaraldehyde) were not significantly different in terms of average overall surface roughness (Ra) and maximum roughness depths (Rq) of different sterilization groups (P>0.1) but the average maximum peak to valley heights (Rz) values of 3 sterilization groups were significantly different (P=0.0415). Dunn test showed that among three post-hoc pairwise comparisons of Rz values, only the comparison of "no sterilization versus autoclaving" was significant (P<0.05) and the other two were non-significant.
Coating might not affect the surface roughness considerably. Brands have different surface roughnesses. Autoclaving but not cold sterilization might affect the surface roughness of coated archwires.
表面形貌是托槽滑动力学中的一个关键因素。关于美观弓丝表面粗糙度的文献较少，且尚无研究探讨任何灭菌方法对这类弓丝表面形貌的影响。本研究的目的是比较普通镍钛（NiTi）弓丝、收到时的美观涂层NiTi弓丝、经高压灭菌或戊二醛浸泡灭菌的美观弓丝的表面形貌。
本体外研究对“American Orthodontics”“Ortho Organizers”“SIA”和“Gestenco”品牌的矩形弓丝进行了80次原子力显微镜（AFM）观察、160次轮廓仪测量观察以及40张扫描电子显微镜（SEM）图像分析。AFM包括8个NiTi正畸弓丝亚组，由4个品牌的涂层正畸弓丝的4个亚组和来自相同品牌的4个未涂层弓丝的4个亚组组成。轮廓仪测量包括16个NiTi正畸弓丝亚组，由4个品牌的涂层正畸弓丝的4个亚组和来自相同品牌的4个未涂层弓丝的12个亚组组成（4个收到时的弓丝亚组、4个经高压灭菌的亚组和4个冷灭菌的亚组）。对扫描电子显微镜（SEM）和AFM图像进行主观评估。对AFM和轮廓仪测量数据进行统计学分析（α = 0.05）。
总体而言，涂层弓丝与未涂层弓丝的表面粗糙度参数差异不显著（P>0.05）。然而，不同品牌的表面粗糙度差异显著。曼-惠特尼检验显示，灭菌弓丝组（两种灭菌方法合并为一组）与未灭菌弓丝组（未灭菌的涂层和未涂层弓丝合并为一组）之间无显著差异（P>0.460）。排除普通未涂层NiTi组后，3个灭菌组（未灭菌、高压灭菌、戊二醛）的涂层弓丝在不同灭菌组的平均总体表面粗糙度（Ra）和最大粗糙度深度（Rq）方面无显著差异（P>0.1），但3个灭菌组的平均最大峰谷高度（Rz）值有显著差异（P = 0.0415）。邓恩检验显示，在Rz值的三次事后两两比较中，只有“未灭菌与高压灭菌”的比较有显著差异（P<0.05），另外两次比较无显著差异。
涂层可能不会对表面粗糙度产生显著影响。不同品牌的表面粗糙度不同。高压灭菌而非冷灭菌可能会影响涂层弓丝的表面粗糙度。
