Objectives: The most desirable characteristic of an ideal elastomeric chain is having light and permanent force.The purpose of this study was to evaluate force decay in 4 commercial orthodontic closed elastomeric chains (Dentaurum,American memory,G&H and Orthotechnology)and also force decay difference in prestretched and non prestretched chains.
Methods: 40 samples of each product divided in 2 groups.The first groups were extended 6 milimeters and the second group in first were stretched by %100 of their initial length and relaxed, and then extended 6 milimeters. The samples were stored in artificial saliva for 3 weeks and thermocycled daily. The force amounts measured in 6 times(2,4,24 hours and 1,2 and 3 weeks) by Dartec testing machine.Anova and Duncan tests were used to determine statistical significant differences among groups.
Results: Force decay pattern in 2 groups of each product was significantly different(p.v=0).The differences among force decay in 4 materials were statistically significant(p.v=0).G&H and Orthotechnology chains in third week were not significantly different (p.v=0.26).
Conclusions: Average force decay in prestretched groups were lower than non prestretched groups.The highest force decay was observed in Orthotechnology chains and the lowest in American memory chains. Prestretching and extension of chains by %40 of initial length would provide the most satisfactory orthodontic force.