Development of Dental Magnetic Attachment with Rare Earth Magnet

A dental magnetic attachment is a denture retainer with a permanent magnet. It has been suggested that such attachment possesses many advantages compared with conventional mechanical attachments, which often pose problems of retentive force durability as well as of esthetics. However, magnetic attachments have not been put into practical use because of the insufficient magnetic attractive force and because of corrosion of the magnet in the oral cavity. An advanced type of dental magnetic attachment has been developed with a sandwich-structuer magnetic circuit, in which a rare earth magnet is surrounded by a pair of yokes. The attachment generates a high attractive force of more than 4.9 N despite its small size. The magnet is sealed with a stainless steel cap, laser-welded to the yoke for perfect protection from corrosion.