Nattrass C, Ireland A J, Sherriff M
Bristol Dental Hospital, Bath, UK.
Eur J Orthod. 1998 Apr;20(2):169-76. doi: 10.1093/ejo/20.2.169.
It is well known that elastomers exhibit viscoelasticity and as such have their mechanical properties modified by temperature. Nickel titanium archwires are also affected by temperature and have been modified with specific temperature related properties for clinical use. What is less well known is the effect that other environmental factors, such as food, might have on the force delivery properties of both elastomeric materials and nickel titanium coil springs used for space closure. For instance gross colour change in elastomeric chain is a common clinical finding in patients who consume spiced foods. The aim of this work was to determine the effect three common environmental factors namely, water, Coke, and turmeric solution have on elastomeric chain and nickel titanium coil springs. In addition, it was decided to re-examine the effect of temperature at 10, 22, and 37 degrees C on both these space closing materials. Unlike many previous investigations, the test specimens were held at a constant stretch throughout the test period, including during their transfer to the Instron Universal Testing machine for force measurement. Six force measurements were made over the first hour, then at 24 hours and 7 days. A control group of dry specimens, maintained at 22 degrees C, had additional measurements made weekly for a 4-week period. The results indicated that elastomeric chain was affected by all the test environments while nickel titanium springs were only affected by temperature.
众所周知，弹性体具有粘弹性，其机械性能会因温度而改变。镍钛弓丝也会受到温度影响，并已针对临床应用进行了具有特定温度相关特性的改良。鲜为人知的是，其他环境因素，如食物，可能会对用于间隙关闭的弹性材料和镍钛螺旋弹簧的力传递特性产生何种影响。例如，食用辛辣食物的患者中，弹性链出现明显颜色变化是常见的临床现象。这项工作的目的是确定水、可乐和姜黄溶液这三种常见环境因素对弹性链和镍钛螺旋弹簧的影响。此外，还决定重新研究10℃、22℃和37℃的温度对这两种间隙关闭材料的影响。与之前的许多研究不同，在整个测试期间，包括将测试样本转移到英斯特朗万能试验机进行力测量时，测试样本都保持恒定拉伸。在最初的一小时内进行了六次力测量，然后在24小时和7天时进行测量。一组保持在22℃的干燥样本对照组，在为期4周的时间里每周额外进行测量。结果表明，弹性链受到所有测试环境的影响，而镍钛弹簧仅受温度影响。
