Abstract

This study aimed to characterize and compare the latest generation multi-force Bio-active™ orthodontic archwires to determine if there is a change in their physicochemical and mechanical properties during orthodontic treatment. The physicochemical characterization of the archwires was done by X-ray diffraction (XRD), scanning electron microscopy, energy-dispersive X-ray spectroscopy and laser-induced breakdown spectroscopy. A modified dynamic nanoindentation method with depth control was used to determine the mechanical properties. Statistical analysis was done by one-way analysis of variance (ANOVA). The XRD analysis showed that all investigated archwires are made of Ni-Ti alloy with an austenite crystal structure. The surface roughness of the Bio-active™ wires decreases after clinical use. The elemental composition analysis showed that the weight percentage of nickel and titanium is approximately 55 wt.% and 45 wt.%, respectively, and traces of Fe and Cr were registered in some regions. The results from nanoindentation experiments showed that the indentation hardness in the bicuspid part of archwires used for six weeks decreases by about 154%, and the indentation modulus decreases by about 44% compared to as received archwires, probably due to the changes in the morphology. Statistically significant differences in the chemical content are found for the anterior and bicuspid regions, while in the mechanical properties, for the bicuspid and posterior regions of the investigated archwires. The obtained results give orthodontists important information about the physicochemical and mechanical properties of the Bio-active™ multi-force archwires during their clinical use.

摘要

本研究旨在表征和比较最新一代多力 Bio-active™ 正畸弓丝，以确定在正畸治疗期间其理化和机械性能是否发生变化。通过 X 射线衍射 (XRD)、扫描电子显微镜、能量色散 X 射线光谱和激光诱导击穿光谱对弓丝进行物理化学表征。使用具有深度控制的改进的动态纳米压痕方法来确定机械性能。通过单向方差分析（ANOVA）进行统计分析。XRD 分析表明，所有研究的弓丝均由具有奥氏体晶体结构的 Ni-Ti 合金制成。Bio-active™ 线材的表面粗糙度在临床使用后会降低。元素组成分析表明，镍和钛的重量百分比分别约为 55 重量％和 45 重量％，并且在一些地区记录了痕量的 Fe 和 Cr。纳米压痕实验结果表明，使用六周后，弓丝二尖瓣部分的压痕硬度下降约 154%，压痕模量较原样下降约 44%，这可能是由于形态的变化所致。前部和二尖瓣区域的化学成分在统计学上存在显着差异，而所研究的弓丝的二尖瓣和后部区域在机械性能方面存在显着差异。