Aim: Accelerating the speed of orthodontic tooth movement should contribute to the shortening of the treatment period. This study was designed to determine whether a pulsed electromagnetic field (PEMF) affects orthodontic tooth movement. Methods: The canines of one side of 10 patients (mean age 23.0 ± 3.3 years) who needed canine retraction were exposed to a PEMF; the canines on the contralateral sides of the same patients were not similarly exposed. After extraction of the maxillary first premolars, both canines were retracted with coil springs. A circuit and a watch battery were used to generate a PEMF (1 Hz). The generator was embedded in a removable appliance. Foil was used to obstruct the contol group from PEMF exposure. Patients were instructed to use the device from the commencement of canine retraction, and it was removed when Class I canine relationship was achieved in either of the canines after 5.0 ± 0.6 months. The changes in the space between the maxillary canine and first molar were measured to indicate the amount of tooth movement. The canine retraction distances were compared by paired t test. Afterward, the treatment plan was continued. Results: With exposure to a PEMF, canine retraction was 1.57 ± 0.83 mm more than the control group (P < .001). Conclusion: These findings suggest that application of a PEMF can accelerate orthodontic tooth movement. World J Orthod 2010;11:e52–e56.
Key words: PEMF, tooth movement acceleration, orthodontic tooth movement, canine retraction