Mousavi Seyed Mohammad, Hormozi Elham, Moradi Mina, Shamohammadi Milad, Rakhshan Vahid
Department of Orthodontics, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Department of Orthodontics, Dental Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
Int Orthod. 2018 Jun;16(2):281-293. doi: 10.1016/j.ortho.2018.03.009. Epub 2018 Apr 7.
The effect of any sterilization methods (cold [chemical] or hot) on load-deflection characteristics of aesthetic coated archwires has not yet been investigated. Thus, we assessed it.
In this experimental in vitro study, 90-coated archwires from 3 brands were purchased. Ten wires from each brand (n=30) underwent cold and 10 underwent hot sterilization, while 10 left unsterilized as negative controls. Load-deflection curves were established for each wire (as five 0.2mm intervals between 1.0 and 1.8mm displacements), using a three-bracket test. After determining the plateau phase that was present in all wires, the averages of plateau phase pertaining to loading and unloading curves and their discrepancies (hysteresis) were calculated for each subgroup (n=10). Average plateau values were compared using two-way ANOVA, Tukey, and independent-samples t-test (α=0.05).
Average loading and unloading values were 906.6±129.7 and 295.9±84.5g respectively (t-test P<0.0001). Comparing loading plateaus, ANOVA indicated significant difference among wire brands (P<0.0001) but not among sterilization types (P=0.4793). Comparing unloading plateaus, ANOVA showed significant differences among wire brands (P<0.0001) and sterilization types (P=0.0008). Tukey showed that only cold sterilization and negative control differed significantly (P<0.001); cold and hot sterilization methods, or control and autoclaving were not significantly different (P>0.05). Comparing hysteresis plateaus, ANOVA indicated difference among wire brands (P<0.0053) but not among sterilization types (P=0.9166).
Cold sterilization might reduce unloading plateau of orthodontic wires, but sterilization in general might not affect loading or hysteresis plateaus. Different brands had different plateaus of loading, unloading and hysteresis.
尚未研究任何灭菌方法（冷[化学]或热）对美学涂层弓丝负载-挠度特性的影响。因此，我们对此进行了评估。
在这项体外实验研究中，购买了来自3个品牌的90根涂层弓丝。每个品牌的10根弓丝（n = 30）进行冷灭菌，10根进行热灭菌，另外10根未灭菌作为阴性对照。使用三托槽测试为每根弓丝建立负载-挠度曲线（在1.0至1.8mm位移之间以五个0.2mm间隔）。在确定所有弓丝中存在的平稳期后，计算每个亚组（n = 10）与加载和卸载曲线相关的平稳期平均值及其差异（滞后）。使用双向方差分析、Tukey检验和独立样本t检验（α = 0.05）比较平均平稳期值。
加载和卸载的平均值分别为906.6±129.7克和295.9±84.5克（t检验P<0.0001）。比较加载平稳期，方差分析表明弓丝品牌之间存在显著差异（P<0.0001），但灭菌类型之间无显著差异（P = 0.4793）。比较卸载平稳期，方差分析显示弓丝品牌之间存在显著差异（P<0.0001），灭菌类型之间也存在显著差异（P = 0.0008）。Tukey检验表明只有冷灭菌和阴性对照有显著差异（P<0.001）；冷灭菌和热灭菌方法，或对照和高压灭菌之间无显著差异（P>0.05）。比较滞后平稳期，方差分析表明弓丝品牌之间存在差异（P<0.0053），但灭菌类型之间无差异（P = 0.9166）。
冷灭菌可能会降低正畸弓丝的卸载平稳期，但一般来说灭菌可能不会影响加载或滞后平稳期。不同品牌的加载、卸载和滞后平稳期不同。
