The 23rd International Conference on Magnetic Applications in Dentistry (Feb. 26 to Mar 15, 2024)
http://jsmad.jp/international/23/

Study on the usage status of dental magnetic attachments after theintroduction of the Japan National Insurance
Kazuhiro Nagata1,4, Masayuki Hidesima2, Chikahiro Ohkubo3, Yasunori Suzuki3, Daisuke
Kurihara3，Kenta Sorimachi4.
1
Nagaoka Dental Communications2
Dental Clinic for Sleep Disorders（Apnea and Snoring), Tokyo Medical and Dental University
Hospital,3
Department of Oral Rehabilitation and Prosthodontics, Tsurumi University School of Dental
Medicine,
4 Department of Comprehensive Dental Care, Niigata Hospital, The Nippon Dental University

I. Introduction
Dental magnetic attachments have been used as aesthetic and protective abutments forremovable partial dentures (RPDs)1. These attachments were approved for use by the Japan
National Insurance in September 2022, and their clinical usage may change. Therefore, weinvestigated the use of the magnetic attachments between September 2022 and August 2023.

II. Objective
Clarify the use of magnetic attachments after the introduction of insurance.

III. Materials and Methods
Survey items:1) Number of cases2) Insurance/self-payment
3) Coping materials and installation methods
4) Denture morphology; overdenture or RPD, metal base or resin base5) Occlusal support (Eichner classifications)
6) Reasons for choosing magnetic attachments
7) Patient’s evaluation of denture8) Dentist’s evaluation of denture fabrication[Web Presentation] PS4-3-1

The 23rd International Conference on Magnetic Applications in Dentistry (Feb. 26 to Mar 15, 2024)
http://jsmad.jp/international/23/V. Results1) Number of cases
Seventy-one magnetic dentures were used in 67 patients.
The patients’ average age was 73.5 years, range, 17–98 years) (Fig.1).

352930case251920171510531002030

11010405060708090age

Fig1. Applicable age for magnetic attachments2) Insurance/self- payment
Forty for magnetic attachments were covered by public insurance, and 83 were fabricated byself-payment (including five implants).
The average number of magnetic attachments used per denture was 1.79 (Fig.2)

3530252015

1050123

Number4of magnetic attachment
5678Fig2. Number of magnetic attachments for a denture3) Materials and installation methods
Coing materials; gold alloy 37, Au-Ag-Pd alloy 90.
Housing for the installation of magnetic assembles; resin housing 68, metal housing 19, and not[Web Presentation] PS4-3-2

The 23rd International Conference on Magnetic Applications in Dentistry (Feb. 26 to Mar 15, 2024)
http://jsmad.jp/international/23/

used 44
Keeper installation; direct bonding 86, welding 41

4) Denture morphology
Overdentures similar to complete dentures; 31, RPDs with clasps; 405) Eichner classifications
A2; 1, A3; 1, B2; 6, B3; 12, B4; 25, C1; 12, C2; 14 (Fig 3).

Fig 3. Eichner classification of the patients6) Reasons for choosing magnetic attachments (multiple answers were available)

411%

67
5 1%5%
8%
141%

314%
220%

1.Poor crown–root ratio; 58
2.Esthetics; 28
3.Rebuild; 20
4.Insufficient occlusal support; 15
5.Cost; 11
6.Transition from conus crown 1
7.Others; 7[Web Presentation] PS4-3-3

The 23rd International Conference on Magnetic Applications in Dentistry (Feb. 26 to Mar 15, 2024)
http://jsmad.jp/international/23/7) Patient evaluation of dentures
Good; 57, fair; 13, poor; 18) Evaluation of denture fabrication by dentists
Easy; 14, fair; 47, difficult; 9IV. Discussion
1) Number of cases
In this study, 71 magnetic dentures were used. The age at application was mostly≥60 years, confirming that magnetic attachments are often used in elderly patients.

2) Insurance/self-payment
Even after the introduction of insurance, the number of cases covered by insurance
remained at approximately 50% of self-payment cases. However, since coping for selfpayment cases occurred before the introduction of insurance, the ratio of insured cases
may increase eventually.
The number of magnetic attachments used per denture was 1–3 (average; 1.92), witha relatively small number being used.

3) Materials and installation methods
The Au-Ag-Pd alloy was used more frequently than the gold alloy for coping in publichealth and self-payment cases. In

the installation of magnetic structures, resin

housings were used in many cases, but approximately 50% of the cases used nohousing.

4) Denture morphology
There were slightly more partial dentures than overdentures.

5) Eichner classifications
With a few exceptions, magnetic dentures were applied to Eicher B2–C2 cases, especially after
B4 cases with loss of occlusal support in the molars.

6) Reason for choosing magnetic attachments.
The reasons for the selection of magnetic attachments tended to be poor crown-root ratio andlack of occlusal support, and they tended to be used in cases with poor abutment toothconditions. The esthetics and cost were less than initially expected compared with the abutment
tooth conditions.

7) Patient evaluation of dentures
Good and fair scores were the most common, with only one case of failure.

8) Dentist evaluation of denture fabrication
Most respondents answered that it was easy or fair, while others answered that it wasdifficult. Because it was assumed that most practitioners in this survey were accustomed to[Web Presentation] PS4-3-4

The 23rd International Conference on Magnetic Applications in Dentistry (Feb. 26 to Mar 15, 2024)
http://jsmad.jp/international/23/

using magnetic attachments, general practitioners likely find it more difficult to use magnetic
attachments.

V. Conclusion
Presently, the insurance coverage for magnetic attachments is only approximately 50% thatfor self-payment attachments.
Magnetic attachments are often used for a small number of remaining teeth (1–3 teeth) withpoor abutments in elderly patients with insufficient occlusal support because they can reduce
harmful lateral forces on abutment teeth, which may be useful for long-term tooth preservation.

References
1. Minoru Ai, Yuh-Yuan Shiau: New Magnetic Applications in Clinical Dentistry,Quintessence Publishing Co., Ltd, Tokyo, 2004.

Acknowledgments
We would like to express a great appreciation to the institutions and their affiliated doctors
for cooperating in collecting patient data.
This study was supported in part by a grant from Japanese Dental Science Federation,
JDSF-DSP1-2023-217-1.

[Web Presentation] PS4-3-5