Effects of aligner activation and power arm length and material on canine displacement and periodontal ligament stress: a finite element analysis.

Using a power arm in canine distalization reduced mesiodistal tipping but increased palatal tipping and extrusion of the canine cusp. Aligner activation and additional force increased tooth movement and principal stress in the canine PDL. FRC power arms exhibited less von Mises stress than SS power arms.