Evaluation of the power arm in bringing about bodily movement using finite element analysis.

Aim: To evaluate the effectiveness of the power arm in bringing about bodily movement and to determine the ideal length and location of the power arm.

Methods: A geometric model of the maxillary right canine was constructed and subsequently converted to a finite element model. Material property data were represented, boundary conditions were defined, and force was applied. Different situations were simulated in which a power arm of varying vertical lengths were attached at different locations on the tooth--namely, the incisal, middle, and cervical thirds.

Results: The amount of bodily movement is maximum when the force is delivered directly at the cervical third. It decreases at the middle third and is least when attached at incisal third. The varying lengths of the power arm for a particular site of attachment does not bring about any change in the movement.

Conclusion: The attachment of the power arm at the cervical third brought about maximum bodily movement, followed by the middle and incisal thirds. Variations in length of the power arm at different sites of attachment did not bring any change in the outcome. Thus, the point of attachment is critical in bringing about bodily movement.