As new materials and technology have become available, magnetic attachment devices have become increasingly sophisticated, making them a viable option for controlling unfavorable lateral forces in the retention of removable prostheses. Various types of magnetic attachments are now available for a wide range of clinical applications. This text presents the fundamental mechanical and biologic concepts of magnetic attachments and their range of applications; introduces other magnet-related technology; and demonstrates their use in 27 clinical cases, many with long-term results.

184 pp; 566 illus; (484 color);

ISBN: 978-4-87417-828-7 , 978487417828;

Contents
1 Introduction
Minoru Ai

Part 1 Fundamentals of Magnet and Magnetic Attachment

2 Magnetic Applications in Clinical Dentistry
Harold W. Preiskel
3 The Technology of the Dental Magnetic Attachment
Yoshinobu Honkura
4 Biological Effects of Magnetic Attachment on the Human Body and Tissues
Tetsuo Ichikawa and Naeko Kawamoto
5 Influences of Magnetic Attachment on Medical Appliances
Toshio Hosoi and Fujio Tsuchida
6 The New Generation of Dental Attachment
Yoshinobu Honkura

Part 2 Clinical Application of Magnetic Attachment

7 A Concept of Designing Dentures and Role of the Magnetic Attachment
Minoru Ai
8 Preparations of Abutments for Magnetically Retained Overdentures
Hiroshi Mizutani and Vygandas Rutkunas
9 Cast base (Coping) System
Hiroshi Mizutani and Vygandas Rutkunas
10 The Root Keeper System and its Clinical Application
Yuh-Yuan Shiau
11 Clinical Analysis on the Reliability of the Magnetic Attachment Over an 8-Year Period
Hiroshi Inoue
12 Maintenance of Magnetically Retained Overdentures and Troubleshooting
Hiroshi Mizutani and Vygandas Rutkunas

Part 3 Clinical Cases

Preface
The magnetic attachment is a retentive appliance of removable partial dentures. This book presented the philosophy and concepts of the magnetic attachment and its application, and is intended to serve as a reference book for daily dental practice.

For removable partial dentures, retentive appliances are essential. Various types of appliances, such as clasps, telescope crowns, and attachments, have been used. They are requested to work effectively to control the movement of dentures, though the mechanism and function of the retention are different among each other. However, while these appliances work effectively, the abutment teeth are suffering from great stress and sometimes break down due to overstress. In other words, retentive appliances have a positive effect to retain the denture effectively and a negative effect to bring stress on the abutment teeth. How to reduce the negative effect is the most important consideration for designing partial dentures.

The retentive function of the magnetic attachment is based on the attractive force of the magnet built in. This magnetic function enables the magnetic attachment to have some unique properties, one of which is the control of unfavorable lateral force to the abutment teeth. This leads to the reduction of the negative effect and provides a great advantage that cannot be achieved in other retentive appliances. Although the magnetic attachment has to be used only on the devitalized root, this can be seen from a different viewpoint as a superior nature, because residual roots can be positively used as abutments of retentive appliance and the periodontal tissue can be preserved as well.

The prototype of the magnetic attachment was completed in 1991, and it has been continuously improved and modified thereafter, based on the development of new magnetic materials and the advancement of new technology. Different types of magnetic retentive appliances for removable dentures have been introduced and applied. We believe many more and better magnetic products will be proposed continuously in the future.

In this situation, it is thought significant to compile the basis and clinical applications of the current magnetic attachment intensively into a book.

This book consists of three parts. In the first part, significance of clinical application of magnet and fundamentals of magnet and magnetic attachment application are discussed. In the second part, technology of magnetic attachment application is introduced. In the third part, 27 clinical cases are presented and discussed. Some of them are long-term outcome reports that should encourage the use of the magnetic attachment for clinicians.

The magnetic attachment has been used clinically for more than 10 years, and its advantages and disadvantages are mostly clarified. It is now recognized in general that the magnetic attachment is a useful retentive appliance for removable partial prosthesis. Taking clasps and telescope crowns or mechanical attachments as the first and second generation of denture retentive appliances respectively, the magnetic attachment can be regarded as the third generation.

Grateful acknowledgment is expressed to those who devoted great efforts to the development and application of the magnetic attachment. We would like to thank Mr. Y. Honkura, PhD, director of Aichi Steel Co., and his staff in the Electromagnetics Division for their ingenious research and development of magnetic attachment. Also, we thank the members of the International Research Project of Magnetic Dentistry (IRPMD) for their support and encouragement. Finally, we would like to thank the late Mr. T. Yoshida, editorial director of Quintessence Publishing Co. for his enthusiasm and efforts in publishing this book.

Edited by:

Minoru Ai, DDS, PhD
Professor Emeritus
Tokyo Medical and Dental University
Tokyo, Japan

Yuh-Yuan Shiau, DDS, MS, PhD
Professor
Department of Fixed Prosthodontics and Occlusion
School of Dentistry, National Taiwan University
Taipei, Taiwan