RESUMO
Objective:To compare the regional load deflection rate(LDR) of multiloop edgewise arch wire(MEAW) in the individual interbracket span,to understand the mechanical properties of MEAW.Methods:The stainless steel wire of 0.41 mm?0.64 mm was bent with single L-loop of 5 different sizes as described by Kim.The LDR of each L-loop at the individual interbracket span when loading and unloading was measured by using the Instron at a crosshead speed of 1 mm/min and maximum deflection of 1.0 mm at room temperature.Five specimens were tested under each experimental condition to eliminate the possibility of changes in the physical properties of the wires as a result of the stress from repeated measurements.The date were analysed by SPSS 11.0.Results:L-loops of MEAW had different LDRs regionally,except the regional LDRs between the canine and the first premolar and that between the first and second premolar were identical and moderate,a high value for the anterior segments and a low value for the posterior segments,the difference was statistically significant(P