Force decay of elastomeric chains – a mechanical design and product comparison study

Abstract

Objectives: To evaluate the percentage force decay of elastomeric chain products utilizing three different design mechanisms simulating canine retraction; and to evaluate the percentage force decay of elastomeric chain products from four different companies.

Design: In vitro, laboratory study.

Setting: LSUHSC Dental School, New Orleans, LA, USA.

Methods: Closed (non‐spaced), grey elastomeric chains from four companies were selected for the study. Three acrylic resin jigs were constructed to provide a framework for three simulated space closure mechanisms. The 6‐5‐3, the chain loop, and the 6‐3 were the configuration mechanisms used in the study.

Outcome measures: An electronic force gauge was used to measure the percentage force decay associated with each elastomeric chain over 28 days at preselected times.

Results: There was a significant difference in the mean percentage force decay for the three different mechanisms (P<0·001). For all four companies, the 6‐3 mechanical design had the smallest mean percentage force decay. There was a significant difference in the mean percentage force decay for the different companies (P<0·001). For all three mechanisms, Ormco had the smallest percentage force decay while Unitek had the highest percentage force decay.

Conclusions: The significant difference in the mean percentage force decay for the different mechanisms suggests that the 6‐3 design is a more efficient means of closing extraction spaces utilizing elastomeric chains.

Keywords:

• Force decay
• elastic chain
• canine retraction

Acknowledgments

The authors would like to thank and acknowledge Leah Balhoff who was responsible for apparatus design and drafting of the article and Anna Kate Milburn who assisted in the execution of the experiment and the collection of the data.