Hirata M
First Department of Prosthodontics, Faculty of Dentistry, Tokyo Medical and Dental University.
Kokubyo Gakkai Zasshi. 1997 Dec;64(4):544-56. doi: 10.5357/koubyou.64.544.
In the 1950 s, a new method of using magnets for the retainers of removable partial dentures (RPDs) was developed. It utilized magnetic attractive force instead of mechanical friction. However, the magnets used in those days were Alnico, Ferrite and/or Pt-Cobalt magnets and their retentive force was not strong enough to stabilize the dentures. Therefore, they gradually went out of use. In the middle of the 1970 s, Samarium Cobalt magnets, which have strong magnetic characteristics, were developed and introduced into dental field. In 1976, Sasaki first applied the samarium cobalt magnets to the retainers of PPDs. While in 1981, Mizutani, et al. first used well-fitted ferromagnetic alloy and the magnet for the purpose of stabilizing the RPD. Since then, many researchers have developed devices such as the magnetic retainer and the closed field magnetic attachment placed on the market in 1992. Now, as for the popular retainer of RPD, one can easily use a smaller yet stronger magnetic attachment which uses Neodium rather than Samarium Cobalt magnet.
20世纪50年代，一种将磁铁用于可摘局部义齿（RPD）固位体的新方法被开发出来。它利用磁吸引力而非机械摩擦力。然而，那时使用的磁铁是铝镍钴、铁氧体和/或铂钴磁铁，它们的固位力不足以稳定义齿。因此，它们逐渐被淘汰。20世纪70年代中期，具有强磁特性的钐钴磁铁被开发出来并引入牙科领域。1976年，佐佐木首次将钐钴磁铁应用于PPD的固位体。而在1981年，水谷等人首次使用配合良好的铁磁合金和磁铁来稳定RPD。从那时起，许多研究人员开发了诸如磁性固位体和1992年投放市场的闭合磁场磁性附着体等装置。现在，对于RPD常见的固位体，人们可以轻松使用一种更小但更强的磁性附着体，它使用钕而不是钐钴磁铁。
