Patent ID: 6036489
Filing Date: 2000-03-14
Classification: A61C

Abstract:
An improved archwire of the type having a substantially rectangular cross-section which, in conjunction with a set of orthodontic brackets having slots to edgewise receive the archwire, applies torque forces to selected teeth, the archwire comprising: a continuous, elongated member of titanium-based alloy formed to have a plurality of segments, including, a curved anterior segment having a centerpoint, which segment, upon insertion into corresponding bracket slots, extends substantially parallel to the four central and lateral teeth with the centerpoint positioned between the brackets on the two central teeth; first and second transition segments, each extending distally from a respective end of the anterior segment; and first and second posterior segments each extending distally from a respective distal end of one of the first and second transition segments; wherein the anterior segment has a built-in torque which varies over the length of the segment, the torque attaining a maximum value at the centerpoint and through a portion of the anterior segment which extends substantially through the slots of at least the two central teeth brackets and then decreasing to a value of about 5.degree. at each end of the anterior segment, each of the posterior segments has approximately 0.degree. built-in torque, and each transition segment has a length whereby, upon insertion of the archwire into the bracket slots, the entire transition segment is positioned between the brackets on corresponding adjacent lateral and cuspid teeth, the transition segments each having a built-in torque which varies from about 0.degree. at the distal end to about 5.degree. at the mesial end, wherein the improvement comprises: said maximum value of said torque having a range of about 21-50.degree..