This type of wire is very useful for space closure in the anterior segment. We just have to place a reverse curve
on the upper maxilla and in the lower maxilla we place a curved wire. This will provoke an extrusion and a palatal
movement of the upper and lower incisors.(ls.21.3o.37)
We generally use round 0.020"or 0.01Tx 0.025" rectangular wire NiTi or TMA.