Repelling magnets versus superelastic nickel-titanium coils in simultaneous distal movement of maxillary first and second molars

Abstract

Eighteen subjects, aged 12.5 to 18.3 years, with Class II malocclusion, deep overbite and moderate space deficiency in the maxilla were treated orthodontically using repelling rare earth magnets on one side and superelastic nickel-titanium coils on the contralateral side for simultaneous distalization of maxillary first and second molars. The force values of the magnets and the coils were calibrated to 225g at the start of treatment and when reactivation was performed every fourth week. Tooth movement was analyzed by measuring dental casts, lateral photographs of dental casts, and lateral skull radiographs before and after 6 months of treatment. Mean distal molar movement was 3.2 mm for the supercoils and 2.2 mm for the magnets. Mean reduction of the overbite was 3.6 mm. Complaints of discomfort were more frequent for the magnet sides. The results indicate that superelastic coils are more effective than repelling rare earth magnets in molar distalization.