Aim: Although much imaging research has focused on the localization and management of the impacted canines, optimal biomechanics for successful recovery are not clear. The purpose of this research was to delineate the three-dimensional (3D) effects of a single force applied using a Kilroy spring on a palatally impacted maxillary canine positioned at different angulations (5 to 40 degrees) with respect to the line of force application. Methods: A dentoform cast was modified to simulate a palatally impacted canine. Load cells placed in the dentoform simultaneously measured the three forces (Fx, Fy, and Fz) and three moments (Mx, My, and Mz) on the canine. The activation range and force system attenuation were measured for eight different positions of a palatally impacted canine (5 to 40 degrees) as the canine moves toward the occlusal plane. The results were analyzed statistically. Results: The minimum activation range for the Kilroy spring was 11 mm, and the maximum was 14 mm. At all the different impacted canine positions, the Kilroy spring had a low load deflection rate and did not require reactivation for the successful management of a palatally impacted maxillary canine. Conclusion: A 3D force system at different bracket angulations (ie, different positions of the impacted maxillary canine) can be successfully quantified using the orthodontic force transducer. Quantification of the force system provides critical information for appropriate selection of an optimal appliance. ORTHODONTICS (CHIC) 2012;13:22–33.
Key words: force system, maxillary canine appliance