According to an article from DentistryIQ, two inventors have invented an orthodontic retention system that uses magnets. US Patent No. 7,854,610 was issued to co-inventors Eugene L. Dellinger and Aron E. Dellinger.

An abstract of the invention, published by the U.S. Patent and Trademark Office, states: "A method and apparatus for delivering an orthodontic retainer system wherein pairs of magnets are applied to adjacent teeth in a patient’s mouth. The retainer system may include a pair of dental modules, in the form of mutually attracted members, that are temporary retained on a delivery member and positioned on a patient’s teeth. In one exemplary embodiment, the dental modules have rounded and/or chamfered edges and a sloped lingual surface. In one exemplary embodiment, the delivery member is substantially L-shaped. Advantageously, the substantially L-shape of the delivery member allows an orthodontist to enter only a small portion of the patient’s oral cavity to position the dental modules on a patient’s teeth. Further, the substantially L-shape of the delivery member eases the orthodontist’s delivery of the dental modules into a patient’s mouth by substantially eliminating the need for the orthodontist to manipulate or otherwise move the patient’s lips, tongue, and/or cheeks."

The full document is available here.