An archwire for use with a passive ligation orthodontic bracket system with a first self-ligating orthodontic bracket having a first bracket body that defines a first archwire slot including a first anterior surface and a first gate that is movable relative to the first bracket body between an opened position and a closed position, in which the first anterior surface and the first gate define a first slot width, the archwire, comprising: an elongated body having a first end, a second end extending therefrom, and a cross-sectional configuration having only two opposing curved surfaces and only two opposing planar surfaces, the two opposing curved surfaces defining a diameter dimension of the body and the two opposing planar surfaces defining a thickness dimension of the body, wherein each of the diameter dimension and the thickness dimension is uniform from the first end to the second end with the diameter dimension being substantially equal to the first slot width； the archwire when received in the archwire slot being able to affect first, second and third order movements of tooth of a patient undergoing orthodontic treatment.
