[Dynamic study of orthodontic wires for Edgewise appliance].

In this research, I conducted a dynamic assessment of both the orthodontic direct force of a round wire and the torque of a rectangular wire, which are used quite commonly for clinical orthodontic treatment. The results are summarized as follows. 1. Leveling .0175" multistranded wire and .016" Ni-Ti wire are orthodontic wires with great flexibility and are superior to others for clinical use at the early stage of leveling. However, if the wire is too firmly legated to the teeth with a flexure of more than 2.0 mm for the former, and more than 0.5 mm for the latter, there is the danger of excessively strengthening the orthodontic force. In the case of .016" stainless steel wire, it is highly possible to give an excessive orthodontic force if it is tied to all the teeth affected by crowding without a bending loop. 2. Torquing Because of their low torque, .017" x .025" multistranded wire and .017" x .025" Ni-Ti wire are suitable for controlling torque from the early stage of treatment. The careless use of .017" x .025" and .018" x .025" stainless steel wires must be avoided because of the possibility of producing an excessive torque on a local part.