Effects of Power Arm Application in Maxillary Canine Distalization

The aim of this study is to investigate the effects of a canine distalization force applied between power arms placed on the maxillary canine and first molar, in comparison with the classical method without power arms. Following maxillary first premolar extraction, canine distalization is commonly accompanied by undesirable effects such as distal tipping and distopalatal rotation of the canine and mesial movement (anchorage loss) of the first molar. By bringing the applied force closer to the teeth's centers of resistance through power arms, the study seeks to move the canine into the extraction space as close to parallel (bodily) movement as possible. The hypothesis is that applying force with Ni-Ti closed-coil springs between power arms placed on the molar and canine teeth reduces undesirable dental effects such as rotation, tipping and anchorage loss during distalization compared with the classical method. In a split-mouth design, 16 patients with maxillary first premolar extractions and moderate anchorage requirement receive power-arm mechanics on one randomly selected side (study side) and conventional mechanics on the other side (control side), with a 150 g force on both sides, over three months of canine distalization.