Comparison of three-dimensional orthodontic load systems of different commercial archwires for space closure

To experimentally quantify the effects of the loop design on three-dimensional orthodontic load systems of two types of commercial closing loop archwires: Teardrop and Keyhole.

An orthodontic force tester and custom-made dentoform were used to measure the load systems produced on two teeth during simulated space closure. The system included three force components along and three moment components about three clinically defined axes on two target teeth: the left maxillary canine and the lateral incisor. The archwires were attached to the dentoform and were activated following a standard clinical procedure.

The resulting six load components produced by the two archwires were reported and compared. The results were also compared with those of the T-loop archwire published previously.

The three designs deliver similar loading patterns; however, the component magnitudes are dependent on the design. All of the designs result in lingual tipping of the teeth, canine lingual-mesial displacement, canine crown-mesial-in rotation, and incisor crown-distal-in rotation.