Influence of initial strain on the force decay of currently available elastic chains over time

Angle Orthod. 2012 May;82(3):529-35. doi: 10.2319/062011-399.1. Epub 2011 Nov 11.


Objective: To investigate the dependence of force decay on the initial strain applied to currently available elastic chains.

Materials and methods: Eight different elastic chains from eight major companies were tested for force decay over a period of 3 weeks at 50% and 100% strain. They were stored in water and thermocycled between 5°C and 55°C. An Instron 3344 was used for the force measurements.

Results: Absolute force values at 50% strain varied between 2.3 N and 4.1 N initially, and between 0.9 N and 1.6 N after 21 days. Thus, the force decay of the elastic chains varied from 37% to 75%. At 100% strain, the force values varied between 2.9 N and 4.7 N initially, and between 1.3 N and 2.1 N after 21 days of continuous strain. The force decay varied between 39% and 67%. Most force decays between 24 hours and 21 days were not significant. This information should be taken into consideration when the appropriate elastic chain is selected for clinical use.

Conclusion: A wide array of elastic chains with various force levels is available. However, differences between products of greater than 100% were measured for force decay over time.

Publication types

  • Comparative Study

MeSH terms

  • Dental Stress Analysis*
  • Elasticity
  • Elastomers
  • Materials Testing
  • Orthodontic Appliances*
  • Orthodontic Space Closure / instrumentation
  • Time Factors


  • Elastomers