Magnets were first used for overdenture retention in 1977. A novelty then, they are now an accepted alternative to conventional attachments, and available commercially from a number of manufacturers. Nearly all of them use a "closed field" magnet configuration, which provides optimum retention and eliminates any possibility of magnetic field effects on tissues. Initial corrosion problems are now being eliminated by improved designs. Clinical experience has shown that overdentures preserve alveolar bone and that magnetic retention can be used effectively on tooth roots which would have a poor prognosis with conventional attachments. Magnets can also be used to retain overdentures against implants as an inexpensive alternative to conventional implant dentures.