Comparison of the force decay over time of four different brands of elastomeric chains (elongated to 25mm grey/transparent and closed/open): An in-vitro study.

ABSTRACT

Elastomeric chains are widely used by orthodontists for incisor retraction and space closure. However, force degradation and permanent deformation are expected to occur. OBJECTIVES: The present study was designed to compare the force degradation of closed, open, grey and transparent power chains from four orthodontic companies (American orthodontics® (AO®), Dentsply®, Ormco® and Rocky Mountain Orthodontics® (RMO®)) over time. MATERIALS AND METHODS: Universal testing machine was used to measure the force of the power chains elongated to 25mm at 0hours, and after storage in artificial saliva at 24hours, 1 week, 2 weeks, 3 weeks, and 4 weeks. A Tukey's honestly significant difference test was performed. RESULTS: Most of the power chains showed less than 30% of force decay at 24hours of elongation. The AO® transparent open elastomeric chains presented the lowest percentage of force remaining at almost all times 24hours (58.9%), 1 week (67.7%), 2 weeks (43.2%), 3 weeks (72.4%), and 4 weeks (63%). Most of the power chains had an increase of force measured after 2 weeks of storage in artificial saliva. Three of the sixteen groups (Ormco® grey open, RMO® grey and transparent closed) displayed an increase in the force at 4 weeks of elongation compared to the force registered at 0hours. CONCLUSION: The results indicated that the force generated by elastomeric chains at 4 weeks remains optimal for a physiologic tooth movement.