Tran Angela M, English Jeryl D, Paige Sebastian Z, Powers John M, Bussa Hank I, Lee Robert P
Department of Orthodontics, University of Texas Health Science Center at Houston Dental Branch (UTHSC-HDB), Houston, TX, USA.
Tex Dent J. 2009 Oct;126(10):981-5.
The aim of this study was to compare the force relaxation between traditional latex elastics to different brands of non-latex elastics in a simulated saliva solution. The force relaxation of 6.35 mm (0.25 inch), 99 g (3.5 oz), non-colored latex elastics from Ormco Corp. and non-latex elastics from Phoenix Orthodontics, ClassOne Orthodontics, and Glenroe was tested. The elastics were stretched to 40 mm (1.57 inch) and the force produced by the elastics was then measured using a Mini 44 Instron machine.
The latex elastics had an initial relaxation of 15 percent after 1 hour of incubation and maintained their reduced force after 24 hours of incubation. Non-latex elastics lost approximately 20 percent of their force after the first hour and continued to lose force after up to 24 hours of incubation resulting in as much as 48 percent force relaxation.
Latex elastics should be used whenever possible; however, when non-latex elastics are warranted, the clinician should take into account their greater initial forces, significant force relaxation, and variability among brands.
本研究的目的是在模拟唾液溶液中比较传统乳胶弹力线与不同品牌非乳胶弹力线之间的力松弛情况。测试了Ormco公司的6.35毫米（0.25英寸）、99克（3.5盎司）、无色乳胶弹力线以及Phoenix Orthodontics、ClassOne Orthodontics和Glenroe的非乳胶弹力线的力松弛情况。将弹力线拉伸至40毫米（1.57英寸），然后使用Mini 44英斯特朗试验机测量弹力线产生的力。
乳胶弹力线在孵育1小时后初始松弛率为15%，在孵育24小时后仍保持其降低后的力。非乳胶弹力线在第一小时后大约失去了20%的力，在长达24小时的孵育后继续失去力，导致力松弛高达48%。
应尽可能使用乳胶弹力线；然而，当需要使用非乳胶弹力线时，临床医生应考虑到它们更大的初始力、显著的力松弛以及不同品牌之间的差异。
