1.A clinical Study of implant denture
with magnetic attachment
Introduction
Magnetic attachments were applied general clinic from
10 years
later. The
clinical results of among 10 years were evaluated
and the application of the new type of magnetic attachments were started.The
design of magnetic attachment for Implant application was different
from general design for natural tooth
application. Because
Implants make osseointegration with alveolar bone,
although teeth have periodontal regiments
and mobility.
This time,we applied magnetic attachments (MAGFIT-IP made by Aichi
Steel),that was developed for Implants.These appliance were applied to
Horse-shoe plate type denture for bilateral canine
of edentutulos maxilla . And so, We report the
new clinical knowledge from this case .
|
2.Stress analysis by the three-dimensional finite element method of the Magnetic
Extracoronal Attachment Although a magnetic attachment is generally introduced on a decoronated
tooth as a stud attachment, we have been considering for many years to apply
it on a vital abutment as an extracoronal attachment. Judging from our
continuous clinical and basic researches, its clinical usefulness is
confirmed. However, as the attachment space which is available in the clinical
site is quite limited, the complete design of extracoronal magnetic
attachment should be very critical. Therefore, a ready-made plastic
pattern which can be casted to dental alloy to fabricate the extracoronal
attachment with a comparatively complex figure, was developed. It can contribute
to both the standardization of the attachment shape and the reduction of time-consuming labo-works. The purpose of this experiment is focused on deciding the most
reasonable design of this plastic pattern based on the three-dimensional
finite element analysis. As a result, the final shape of the pattern was suggested through these
experimentations. It is minimal in size and can provide satisfactory
mechanical strength to stand the functional occlusal stress. Poster Questionate
|
|
|
3.A Guideline For
Prosthetic Design Using Magnetic Attachments
－with
a Focus on Application to Implant-supported Restorations－
Magnetic
attachments have become increasingly viewed as an effective aid to resolving
prosthetic problems and widely accepted as an alternative to conventional
mechanical attachments. The retention mechanisms (“magnetic” verses
“mechanical”)of these 2 types of attachments are completely different in
nature. Accordingly, prosthetic design guidelines must be established to ensure
that magnetic attachments are able to fully achieve their unique performance
potential. In our previous report, we classified magnetic attachment
applications into 3 categories according to the functional roles to be
attained, which are Type R (the functional priority is placed on “retention”,
not on “support” or “bracing”), Type SR (the main purpose is “support and
retention”, not “bracing”) and Type BSR (“bracing, support and retention” are
equally expected), and suggested the importance of establishing prosthetic
design guidelines for each of these 3 categories.
As a practical approach for clinical
application, we have developed a “design chart” that is based on the
abovementioned functional classification. The chart simplifies the design
process of complete and partial dentures using magnetic attachments, and has
proven to be effective for our patients. This presentation reports the advantages
and effectiveness of the design chart as well as those of MACS System.
|
4.
Fundamental Investigation About an Optimum Design of Crown and Bridge Made of the Pt-Fe Magnetic Alloy Using the
Integral Element Method The Second Report
Applying a commercial dental magnetic attachment to a
removable-type crown bridge presents various problems. As a solution, a
removable crown bridge system was assembled with a Pt-Fe magnet crown and a
soft magnetic stainless steel core. Dental castings of a Pt-Fe magnet alloy
outer cap and a magnetic stainless steel inner cap have already been investigated.
In our last report, using an integral element method, a 3-dimensional
magnetic field that follows the disk model was analyzed in an attempt to
determine the optimal method for design and magnetization. The results
indicated that four-pole magnetizing offers a reasonable magnetization
pattern for Pt-Fe magnet disks. In this paper, the attractive force of the
Pt-Fe magnet disk (φ9×2㎜) to the magnetic stainless steel disk by
dental casting was investigated, and the results were compared to the
analytical results by the integral element method. Furthermore, reliable
calculation conditions of the magnetic characteristic of the Pt-Fe magnet and
the magnetic stainless steel were discussed. |
5. Influences of Thermal Cycle on
Attractive Force of Magnetic Attachment.
A magnetic attachment, which utilizes not friction but its attractive force for denture retention has many advantages. The retentive force is numerical and its lateral force is very small. Whereas the corrosion, which was only one disadvantage, is prevented by laser welding. However, it is not clear whether the attractive force is durable under the condition of oral cavity. The purpose of this study was to measure the attractive force of the magnetic attachment experimentally and clinically. 40 magnetic attachments (Hi-Corex, Hitachi Metals Co.,Ltd.) were used in this experimental study and dipped into 5℃ and 90℃ water tank for 1 minute alternatively(1 cycle). After 10,000 and 20,000 cycle dips the attractive force were measured. On the other hand,28 patients(52～82years), inserted magnetic partial dentures, were participated in this clinical study and measured the attractive force before and after 6months, 1y., 2ys., 3ys.. The results were as follows: The mean rate of force reduction after 20,000cycles was 0.84±0.05%, whereas that after 3y. was 4.88±1.69%.These were not significant(p≧0.01, byScheffe's post-hoc test ).
Hence it is concluded that the attractive force of the magnetic attachment is
not changeable in the oral cavity. Poster Questionate
|
|
6. Design of an
Uniform Magnetic Field Exposure System for Experiments of Biological Effects
of Magnetic Fields on Culture Cells |
|
7.Approximation of
Gap-force Characteristics for Dental Magnetic Attachments Authors have proposed various typed
magnetic attachments for the requirements in clinical use. Some have large
retentive force at a comparatively large gap between a keeper and a magnet
assembly. And,some have little retentive force at a small gap. When we
synthetically evaluate the dynamic retentive characteristics of the magnetic
attachment,it is useful to show them of the various types of magnetic
attachments by simple function of gap. We demonstrate the expression for the
closed field type of magnetic attachments,and show their characteristics by a
simple linear equation. As a result,it will be able to evaluate the entire
retention characterisics when a same kind of the magnetic attachment are used
in plural and when different kind of them are applied in clinically. In
addition,it will be possible to evaluate the general retentive
characteristics by means both of the mechnical and |
.mwee