New magnetic applications in clinical dentistry

  • M. Ai &
  • Y-Y. Shiau
UK: Quintessence price £50, pp 184 ISBN 4874178286 | ISBN: 4-874-17828-6

This is a unique, very interesting book on a subject that has received little attention in recent years. The authors are 15 Japanese academics, a director of the Aichi Steel Corporation of Japan and Harold Preiskel from the UK. The book is an updated version of a text originally published in Japanese in 1994. As a consequence, perhaps, of the translation, some of the spelling and English is somewhat inconsistent. The book is nevertheless very well presented and beautifully illustrated. It is divided into three parts: Fundamentals of magnet and magnetic attachment; Clinical application of magnetic attachment; and Clinical cases.

The use of magnets in prosthetic dentistry is not new but after early reports in the 1980s rather fell from favour as a consequence of problems experienced with earlier types of magnet. These problems related to their size, low retentive force and corrosion. It is claimed by one of the editors of the book that these problems were completely solved in Japan in 1990 and this book provides a comprehensive exposition of new developments since then. The break-through appears to have come with the replacement of samarium-cobalt magnets with neodymium-iron magnets which are more powerful and can be made much smaller. The problem of corrosion has been overcome by micro-laser welding corrosion-resistant stainless steel casings for the magnets. Root keepers can now be fixed directly to the root surface of abutments either by the use of adhesive restorative materials or with systems where the keeper forms part of a cast or prefabricated restoration.

Every aspect of health and safety, biological effects of magnets on the body and possible influences of magnetic attachments on medical devices is explored. The advantages and disadvantages are fully covered as is the concept of designing dentures with magnetic attachments. It is disappointing that the only follow-up data on the use of such devices is based on a relatively small number of patients (77) treated by different operators at Osaka University Dental Hospital. Over an eight year period the most commonly encountered problems were denture fractures, dislodgement of the magnetic assembly from the denture base and dislodgement of keepers from copings.

In the final section of the book, 25 cases of conventional removable partial dentures and two cases of implant retained dentures using magnetic attachments are presented. There is also a comprehensive listing of all dental magnet attachments that are sold in Europe and the USA.

This book is an extremely useful source of reference for anyone contemplating the use of magnetic retention either for conventional or implant retained prostheses.