Dittmer Marc Philipp, Demling Anton Phillip, Borchers Lothar, Stiesch Meike, Kohorst Philipp, Schwestka-Polly Rainer
Department of Orthodontics, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Deutschland,
J Orofac Orthop. 2012 Aug;73(4):289-97. doi: 10.1007/s00056-012-0086-z. Epub 2012 Jul 11.
Orthodontic elastomeric chains are a main component in orthodontic therapy with fixed vestibular or lingual appliances. The objective of this study was to investigate the influence of artificial aging on the mechanical properties of orthodontic elastomeric chains (power chains, PCs) without an intermodular link using a test setup according to DIN EN ISO 21606:2007.
In this study, 11 types of PCs supplied by seven manufacturers were investigated. Four groups with 10 specimens each were randomly generated for each type. Samples were separately mounted in a universal testing machine and extended by 300% (four times their initial length) at a crosshead rate of 100 mm/min and were held at this position for five seconds. The chain length was then reduced to three times the initial length (extension by 200%) and kept for 30 s. Then, within the control group (t = 0) and the force Fmin was recorded before extension until failure was performed and force (Fmax) and length (Lmax) at failure were determined. After prestretching, specimens of the three other groups were stored in water at 37°C with its three times initial length for one day (t = 1), 14 days (t = 2), and 28 days (t = 3), respectively. The specimens were then placed in the universal testing machine and the residual force (Fmin) measured, so as to subsequently extend them until failure at Fmax and Lmax. Data were statistically analyzed by one-way analysis of variance; the level of significance was set at p = 0.05.
Statistical analysis revealed significant differences in Fmax, Fmin, and Lmax in each group (t = 0 to t = 3) between the various manufacturers (p < 0.001). Moreover, artificial aging significantly influenced Fmax, Fmin, and Lmax (p < 0.001).
The orthodontist should consider both the mechanical properties of PCs and the duration of these appliances' application when treating patients. Artificial aging had a significant influence on the parameters we determined (p <0.001).
正畸弹力链是固定前庭或舌侧矫治器正畸治疗的主要组成部分。本研究的目的是根据DIN EN ISO 21606:2007的测试设置，研究人工老化对无模块间连接的正畸弹力链（动力链，PCs）力学性能的影响。
本研究调查了七个制造商提供的11种PCs。每种类型随机生成四组，每组10个样本。将样本分别安装在万能试验机中，以100 mm/min的十字头速度拉伸300%（初始长度的四倍），并在该位置保持5秒。然后将链长缩短至初始长度的三倍（拉伸200%）并保持30秒。然后，在对照组（t = 0）中，在拉伸直至破坏之前记录力Fmin，并确定破坏时的力（Fmax）和长度（Lmax）。预拉伸后，其他三组的样本分别在37°C的水中以初始长度的三倍保存1天（t = 1）、14天（t = 2）和28天（t = 3）。然后将样本放入万能试验机中测量残余力（Fmin），随后将其拉伸直至在Fmax和Lmax处破坏。数据采用单因素方差分析进行统计分析；显著性水平设定为p = 0.05。
统计分析显示，不同制造商的每组（t = 0至t = 3）在Fmax、Fmin和Lmax方面存在显著差异（p < 0.001）。此外，人工老化对Fmax、Fmin和Lmax有显著影响（p < 0.001）。
正畸医生在治疗患者时应考虑PCs的力学性能以及这些矫治器的使用时间。人工老化对我们测定的参数有显著影响（p <0.001）。
