Our education of magnetic attachment to the dentist clinical residents.
S.Nakabayashi
Department of Partial Denture Prosthodontics, Nihon University School of dentistry

Introduction
Although we have educated a magnetic attachment during a student's lecture and hospital practice,
the fact is that they who became dentist clinical residents do not understand and remember thefeatures or use.
The magnetic attachment is device useful to clinical, but they may not notice the usefulness if they
don't understand the correct form and method of magnetic attachment.
Moreover , it is thought that the magnetic attachment may not be appled as one of the treatment
methods in the future.
Thus, we included practice of the magnetic attachment in the education of the partial denture offive days, since dentist clinical training system was introduced into dental school graduates 7yearsago.
Then, we introduce the education contents and practice.

Objective
Our educational objective make it understand so that residents can apply a magnetic attachment toclinical correctly with simple practice which used the gnathic tooth model while having explained
the feature, the indication, method and research result.
Therefore, we introduce the educational contents.

The content of an education and practice1.

A magnetic attachment is what?
First of all, since we want dentist clinical residents to have an imagery of a magnetic
attachment, we teach how a magnetic attachment is generally applied using a scheme as shownin Fig.1, and explain the magnet assembly and keeper which constitute the magneticattachment(Fig.2).

Next, a clinical example explains how the magnetic attachment is used by clinical(Fig.3). A
magnetic attachment is the cause and turn of a trouble, if they cannot understand the feature andcorrect method including a prosthodontics planning, although it is an apparatus usefulclinical(Fig.4).
Therefore, if it applies to clinical without their understanding a magnetic attachment well, wewill advise that they cannot demonstrate the useful of a magnetic attachment.
For that reason, it is necessary to motivate of what of a magnetic attachment dentist residents
should understand in future to dentist residents.

2.

Feature of magnetic attachment
First, the feature of a magnetic attachment is that it is semipermanent retentive power, thepower of absorption is perpendicularly demonstrated by the maximum, and the repositioning
power of absorption acts (Fig.5).
However, it may be hard to remain in dentist clinical residents' reminiscence even if it teaches
these three features schoolbook, and there are many questions from students or intern doctors
why a magnetic assembly is not installed in the stud attachment side. it is a consider that wewill not remain in dentist clinical residents' reminiscence even if it teaches these three featuresschoolbook.

Thus, although a time is taken, we mind to educate containing the reason so that features may
remain in their reminiscence.
The returning power of absorption which can be called important feature of a magnetic
attachment requires explanation with an AirGap curve(Fig.6), and the Curie-temperature curvein a paramagnetic body shows the curve to which a magnetic flux density falls along with a risein temperature(Fig.7). That is, since a ferromagnetic property is lost at the thermo of casting,
we explain including a reason that a magnet assembly loses power of absorption.
As mentions above, when it expounds that the feature of a magnetic attachment is associatedwith a research result, a scheme or a clinical case, students and dentist clinical residents haveturned to the convinced countenance.
And, we grab their hart and advance to the next description.
3.

Form and classification of magnetic attachment
An appropriate design of coping is often explained that the height of a metal cap is as much as
possible low and it is important that a keeper installs in a position near lingual-side(Fig.8).
Then, we verified the influence on tooth root by the difference in height and form of coping as
shown in Fig. 9. the result of experiment suggested that it is most little influence to tooth rootthat the form of a metal cap is made low as much as possible and a keeper's positionis arrangednear lingual-side.
Moreover, the coping needs to be a form in line with a marginal gingiva. otherwise, a marginal
gingiva will cause a chronic inflammation and abutment teeth turn to poor prognosis(Fig.10).
They notice for the first time that the significance of a form is important.
4.

Relation between magnetic attachment and MRI(magnetic resonance image)In MRI photography, a keeper's artifact has a provide probability in an interpretation ofradiogram in an influence greatly, and the size is about 4-8 cm by the SE method(Fig.11).
But, the MRI image diagnosis of a carcinoma of oral cavity is considered to be an important ina dentistry territory.

Then, we devised the magnetic attachment which made the keeper of the cause of an artifact
the withdrawal possible(Fig.12,13).
5.

Practice of magnetic attachment
As a resource of practice, the gnathic tooth model (Fig. 14) used for practice is a mandibularmodel to which the right-and-left dentes canini remains. And the magnetic attachment is using
D600 which is a "GIGAUSS" D type made from GC.
Although the feature of the magnetic attachment, etc. were explained before training, they will
ask a question after training and will deepen a understanding(Fig.15.16).

Conclusions
We made the dentist resident understand the magnetic attachment obtained from the content ofa study, the result, and they experienced the difficulty of the operation of a magnetic

attachment by training. and we consider that they apply a magnetic attachment to clinical and tocontribute to improvement in a patient's QOL.
Therefore, we share with staffs the knowledge acquired by research of the magnetic
attachment, and are educating it by all staffs.
Although it is an introduction of a part of educational content this time, we relate with amagnetic attachment, a scheme, a clinical example, a research result, etc., and think it important
for an education to explain.