ABSTRACT
The magnetic systems as retention units in overdentures are especially used in dental prosthetics designed on the appropriate endodontically treated dental root. With the rapid development of materials and technology their application with overdentures on implants is enabled. In dentistry for a long time magnets made from alloys of aluminium - nickel - cobalt have been used with open field. Their success was limited because these magnets are susceptible to corrosion in contact with saliva and because their retention force is weaker than that retention offered by the mechanical attachments. The preparation of the magnets from alloys of rare earth elements samarium and neodymium enabled greater magnetic force per unit size. Also a new generation of containers allows laser welding with which the protection of the magnetic units from salivary corrosion has been improved. The interest in such attachments is growing which is justified, because the magnets, unlike mechanical attachments have the potential of unlimited duration and may be superior to either mechanical ball or bar attachments in achieving retention for overdentures. Moreover, the magnetic unit provides little resistance to lateral displacement, with which the impact of potentially damaging lateral forces on the retention tooth or implant is reduced.