#9
Longitudial Study of Magnetic Attachments
ーCharacteristic of Long-term Success Casesー |
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| T.Shigemori，K.Hoshiai，K.Watanabe，R.Ito，T.Kawaguchi T.Yokoyama，M.Miwata，N.Kimura，Y.Tanaka
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Department of Removable Prosthodontics,
School of Dentistry, Aichi-Gakuin Universty
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| Introduction |
| Magnetic attachments have increasingly been used in the treatment
of various cases. However, the usefulness of magnetic attachments has not
yet been confirmed. Thus, we carried out a postoperative investigation
of magnetic attachments from 1993, and report our findings in this study.
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| Methods |
| 1,400 teeth were used as abutments fitted with magnetic attachments.
252 teeth set in 105 metal plates dentures were selected for postoperative investigation.
Untracable teeth were 117, the number of extracted teeth were 29, and remaining teeth were 106.
The survival probability of all abutment teeth was calculated using a Kaplan Meier analysis.
The survival rate of abutment teeth with metal plate was approximately 88% after 10 years and approximately 77% after 15 years.
The red line shows resin plates which were used during the same period.
A random sampling of resin plates were selected of 111 abutment teeth.
The survival rate of abutment teeth with resin plate was 70% after about seven years and 53% after about 10 years (Fig1).
The survival rate of metal plates tended to remain fixed after about 10 years, as compared to resin plates which tend to have a fixed survival rate after about seven years. Postoperative investigation was conducted to confirm the condition of abutment teeth in the metal plate at this period where the survival rate tended to remain fixed. Out of 17 cases (51 teeth), 11cases (25 teeth) were investigated.
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| Results |
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| Table1 shows the outline of cases investigated. The average age was
74.2 years. The subjects were 2 males and 9 femals. These patients were
diagnosed with a systemic illness. There was a single case where the magnetic
attachment was applied to both the maxilla and mandible magnetic attachment
was applied in 5 cases each of maxilla and mandible. The breakdown of attachment
is 2 incisor teeth, 6 cuspid teeth, 6 premolar teeth, 11 molar teeth. The
average survival time was 155 months or about 13 years. |
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| Table2 shows the general condition of dentures. Only 2 subjects were
regularly doing the recall, and 2 cases were burshing their 3 times a day.
Half of the cases were using the denture’s brush when cleaning their dentures.
2 cases wore the dentures when they sleep. |
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| Table3 shows the state of the abutment teeth.
Adjustments were from tooth 1~ 5.
Seven cases, more than half of the total number of cases, involved adjustment of more than one teeth.
The majority of he periodontal pocket depth measured by 6 point method were less than 4mm and the maximum value was 7mm.
Many abutment teeth showed mobility in the range of M0～M2.
Case No.8 abutment tooth that showed the depth of the periodontal pocket 7mm and on other point 1mm and M0.
Case3 the depth of the periodontal pocket was 5mm, and tooth mobility of M3 thus was suitable for tooth extracyion.
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| Table4 shows the state of masticatory function of each case. It seemed
that sufficient mastication was achieved by almost all the cases. As evidenced
from the masticatory score. Similar results were obtained by using dental
prescale. The contact side product average was 6.0mm2 , the maximum occlusion
power was 84.1N, and the contact point was 10.9 points. Therefore, the
artificial dentures were functionallyg acceptable. |
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| Discussion |
| Magnetic attachments were applied to maxilla so that the arrangement
of abutment teeth were aligned on both sides. The Kennedy’s classification
is from class Ⅰto class Ⅴ． The Eichner’s classification is class B to class
C. The number of magnetic attachment to the mandible were fewere as, compared
to the maxilla and the periodontal pocket depth remained same except for
a single case. |
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| Conclusion |
We carried out the postoperative investigation on magnetic attachment
that had been in use for 13 years. 1. Cases which had magnetic attachment
in to the maxilla, had a large number of abutment teeth per plate. 2. For
mandible magnetic attachment, the number per plate were few. 3. Judging
from the condition of the dentures and abutment teeth, it seems that dentures
continue to function well and last for extend period.
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