The postoperative investigation of the abutment teeth using a magnetic
attachment.
H. Kumano, R. Kanbara, T. Masuda, H. Nakamura, S. Tanaka and J. Takebe
Department of Removable Prosthodontics, School of Dentistry, Aichi Gakuin University
Abstract
The magnetic attachments can be small and powerful attractive force by using a neodymium magnet
which is one of rare earth magnets. This system can be used as abutment teeth by decreasing the lateralforce even if crow-root ratio is poor. Therefore the clinical efficacies of a magnetic attachment have been
widely demonstrated. It is thought that it is necessary to observe the long-term progress of the abutment
teeth after setting of the magnetic attachment to get a good clinical result. The purpose of this study was toobserve the long-term progress of abutment teeth with magnetic attachment. The investigation period wasfive years from 2008 to 2013, and it was the case of regular visits. As a result of postoperative investigationof abutment teeth, the following knowledge was obtained. The number of teeth with magnetic attachment
was 257, and the maxilla was more than 1.5 times larger than the mandible. The number of lost teeth of theabutment teeth with magnetic attachment in the investigation period was 48, the maxillary first premolar
was the most, and the order of mandibular first premolar and maxillary canine was followed.

Introduction
These newer encased magnets provided improved corrosion resistance and improved magnetic attachment
retention and clinical durability. As newer magnetic materials have been developed, the advantages of size
reduction, stronger attractive retentive force, and improved clinical utility and use have substantially
improved the range of useful applications compared to earlier versions previously available. While certain
types of esthetically hidden precision attachments are considered rigid and inflexible, magnetic attachments
are considered more capable of stress release due to an inherent ability to minimize and reduce unfavorable
horizontal mechanical force transfer. Reduced horizontal force transfer for prosthetic retentive elements has
been considered advantageous in preventing abutment overload and unwanted breakdown. A smaller
attachment size is also of greater benefit for esthetic adaptability and constrained space applications1, 2). To
observe the long-term progress of abutment teeth after setting of the dental magnetic attachment isindispensable in order to obtain good clinical results, diagnosis, designing denture and maintenance of theindex3).

Objective
The purpose of this study was to observe the long-term progress of abutment teeth with the dental
magnetic attachment and to understand the real condition of abutment teeth.

Materials and Methods
The investigation period was five years from 2008 to 2013, and a dental magnetic attachment was set atmagnet denture clinic, Aichi Gakuin University Dental Hospital, and it was a case that is undergoingregular maintenance. In addition, the abutment teeth were used only for the root cap with the keeper coping,
and the Magno-telescopic Crown and the implant using the magnetic attachment was excluded.

Results
In the investigation control group, 28 males and 59
females totaled 87 people and the average age was 73.4
years old. The denture using the dental magnetic
attachment as the retainer was a total of 103 plates, 55
plates in the maxilla and 49 plates in the mandible (Fig.
1). Comparing the difference in material, the denture of
the maxilla was 43 plates (78%) of metal base denture,
12 plates (22%) of resin base denture, the denture of
the mandible was 28 plates (57%) of metal basedenture, 21 plates (43%) of resin base denture (Fig. 2).
The number of abutment teeth with dental magnetic
attachment was 257. The number of abutment teeth in
the maxilla was 152, and the number of abutment teeth
in the mandible was 105 (Fig. 3). Comparing themaxilla with mandible, the number of dental magnetic
attachment that was set to the maxilla was about 1.5
times that of the mandible. This time, the number of lost
teeth of the abutment teeth with dental magnetic
attachment was 48. The extraction was 34, detachmentof the magnet assembly and the root cap with thekeeper coping was 14. Breakdown of the number oflost teeth in the maxilla, the extraction was 17, thedetachment of the magnet assembly and the root cap
with the keeper coping was 11. Breakdown of thenumber of lost teeth in the mandible, the extraction was17, the detachment of the magnet assembly and the root
cap with the keeper coping was 3 (Fig. 4). The numberof lost teeth set to the dental magnetic attachment in the investigation period in the tooth type of the maxilla
and mandible is shown in table 1. The number of lost teeth set to the dental magnetic attachment was themost in the maxillary first premolar, followed by the mandibular first premolar and the maxillary canine.

Discussion and Conclusion
As a result of the postoperative investigation of the abutment teeth set to the dental magnetic attachmentfrom 2008 to five years in 2013 at magnet denture clinic, Aichi Gakuin University Dental Hospital, thefollowing knowledge was obtained.
1．Both the maxilla and mandible was more metal base denture than the resin base denture.
2．The number of abutment teeth with dental magnetic attachment was 257. The number of dental magnetic
attachment that was set to the maxilla was about 1.5 times that of the mandible.
3．The number of lost teeth of the abutment teeth with dental magnetic attachment in the investigation
period was 48. The maxillary first premolar was the most in, followed by the mandibular first premolar andthe maxillary canine.

References
1. Tanaka Y. New Magnetic Attachment –New Prosthetic Treatment using magnets-.1st Ed. Tokyo:
Ishiyaku Publishers Inc; 2016.

2.Tanaka Y, Nakamura Y, Hoshiai K. General remarks concerning magnetic attachments in dentistry. Proc
Japan Acad; 78(5): 97-105,2002.

3. Ito R, Hoshiai K, Tanaka Y and et al: Longitudinal Study on Metal Plate Denture with MagneticAttachments, JJ mag Dent;18(2):8-14,2009.