و ارتوتكنولوژي G

Comparative evaluation of force decay in four orthodontic closed elastomeric chains (Dentaurum, American, G&H and Orthotechnology)

Background and Aim: The most desirable characteristic for an ideal elastomeric chain is the possession of a light and permanent force which unfortunately is not observed with commercially available chains. The purpose of this study was to evaluate force decay in 4 commercially available orthodontic elastometic chains (Dentaurum, American memory, G&H and orthotechnology) and the effects of different elongation ranges on force decay pattern, and also force decay difference in pre-elongated and non pre - elongated chains. Materials and Methods: Sixty samples of each product were obtained and divided into three groups. The first groups were extended 3 millimeters, second groups were extended 6 millimeters and third groups were firstly stretched by 100% of their initial length and relaxed and then extended 6 millimeters. The samples were stored in artificial saliva for 3 weeks and thermocycled daily. The force amounts were measured at 7 times (0, 2, 4, 24 hours and 1, 2 and 3 weeks) by DARTEC machine. ANOVA and DUNCAN tests were used to determine statistically significant differences among groups. Result: Force decay patterns in these 12 groups were evaluated and compared. Force decay patterns in 3 groups of each product were significantly different (P.V = 0.000). The differences in force decay between 4 products were statistically significant (P.V = 0.000). G & H and orthotechnology chains were not significantly different in the third week (P.V = 0.26). Conclusion: The higher initial force cannot increase force decay. Both the force amount and force decay, in the third group, were lower. The highest force decay was observed in orthotechnology chain and the lowest in American memory chain. Pre - elongation and extension by 40% of the initial length would provide the most satisfactory orthodontic force.