In this study, effect of the cross section shape on the ion release of different orthodontic alloys as well as subsequent weight changes was investigated. In vitro experiments were carried out on three different alloys: stainless steel, nickel-titanium, copper-titanium alloys. Both round and rectangular wires were utilized. The results revealed that the cross section did not have considerable impact. In case of stainless steel and nickel-titanium alloys, the round cross section revealed high ion release. However, in case of nickelcopper- titanium alloy, the rectangular cross sectional wires showed more ion release. Concerning weight changes, stainless steel wire showed more weight increase. Conversely, rectangular copper titanium wire showed weight loss.