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Abstract
This study evaluated two different bracket systems using two types of arch-wires (0.016 x 0.022 inch stainless steel and nickel-titanium) in a human sample. Fourteen patients were selected and removed the first premolars in both arches. Each subject received two different brackets (synergy and conventional) placed on both arches. The sample divided to two groups according to arch wire used. The amount and time of retraction and anchorage loss was measured using a computer program. The results revealed that stainless steel wires and synergy brackets produced less friction compared with nickel titanium wires and conventional brackets.