ABSTRACT
Different behavior of stainless-steel wires manufactured by different companies is observed in clinical situations. The purpose of this study was to compare the load-deflection rate of a specific size of stainless-steel wire from different companies which are available in Iran,s commercial market. This comparison allows classification of these wires and also the wire with best characteristics will be clarified. This experimental study was carried on cross-sectional base. Round 0.016 inch stainless-steel wires from 9 different companies were used in this investigation. 14 wires from each company were chosen on random base. 14 Wires from each company were divided in two groups of 7, group A and B with 3 and 1.5mm deflection respectively. The tests were done using Zwick testing machine model Z250. Loading and Unloading forces of wires in predetermined distances were measured. The total of 126 tests were measured. Upon these measurements, the load-deflection curve was drown. Using SPSS software the one-way analysis of variance [ANOVA] was done and each wire from a company was compared to other companies using Tukey analysis. The load deflection curves obtained were similar to typical curve of stainless-steel wires. The one-way analysis of variance [ANOVA] showed that there was no significant difference between the wires belonged to group A in three different deflection, i.e. 2.5, 2, and 1.5mm at a level of 5%, but he difference between the wires belonged to group B in 1.5 mm deflection was significant [P<0.001]. In this study it was found out that among the 9 different wires, tested, the RMO wites produced the minimum force levels and Dentaurum wires produced the maximum force levels in both groups. This means that RMO wires had better tissue compatibility. Moreover, it was found out that even the wires made by the same factory did not have a similar behavior. Among the tested wires, the Ortho technology wires had minimum and the GAC ones had maximum similarity to each other