A case report of a removable partial denture using a magnetic attachment
considering the load-bearing capacity of abutment teeth
M. SONE, D. MATSUMOTO, N. KOYAMA, F. NARUMI, T. MATSUKAWA, S. UCHIDA, S.
SOMEKAWA, K. TAKAHASHI, M. SUZUKI, Y. MIYOSHI, T. YOSHIDA, D. SAKAMOTO, K.
OKAMOTO, and S. OHKAWA
Division of Removable Prosthodontics, Department of Restorative and Biomaterials Sciences, Meikai
University School of Dentistry

Abstract
In this presentation, we report on a case in which two different types of magnetic attachments,
depending on the load-bearing capacity of the abutment teeth, were applied to one removable partialdenture.
The patient, a 59-year-old male, complained of masticatory dysfunction. He had a partially edentulous
maxilla (Kennedy Class II). After the initial preparation, the distal root of the mandibular right second
molar was fitted with a coping magnetic attachment in consideration of its load-bearing capacity as anabutment tooth, and we decided to fabricate an extracoronal magnetic attachment using an EC Keeper
Tray (GC, Japan) for the mandibular right first and second premolars.
The definitive denture had the first molar as a homemade metal tooth and the second molar as a hardresin tooth (SR-Orthosit-PE, Ivoclar-Vivadent AG, Liechtenstein). In addition, GIGAUSS (GC) wasused for a magnetic attachment (the coping type was the D400, and the D600 was applied to theextracoronal type).

Introduction
Prosthetic treatment options for a partially edentulous maxilla have been increasing in recent years.
In particular, many patients choose implant treatment rather than a removable partial denture due to thesuperiority of chewing efficiency and foreign body sensation (Fig. 1).

Fig. 1 A case of implant treatment
However, in Japan, patients with systemic diseases are increasing, and as an alternative to implant
treatment, conventional treatment using partial dentures that have “Syoku-Riki” (the ability of predation,mastication and swallowing) is necessary for maintaining patients’ QOL, which leads to the extension ofhealthy life expectancy.1)

A magnetic attachment (Fig. 2) can exert stable maintenance power by using the suction force of themagnet for the desorption of the denture at the time of chewing. In addition, it is possible to apply
various support devices to the abutment teeth in various conditions, which has various advantages for theelderly, such as easy attachment and removal by the patient. In other words, depending on theapplication method, denture support device can maintain and improve “Syoku-Riki”. In this presentation,
we report on a case in which two different types of magnetic attachments, depending on the load-bearing
capacity of the abutment teeth, were applied to one removable partial denture.

Fig. 2 A case of a denture using a magnetic attachment

Clinical History
Clinical History: The patient, a 59-year-old male, complained of masticatory dysfunction. He had apartially edentulous maxilla (Kennedy Class Ⅱ) and a history of arrhythmia. He complained that hewanted to seat the denture firmly on his right jaw, but he did not want the implant treatment due to hiscurrent systemic history.

Fig. 3 Intraoral view at the first visit
Treatment Procedure: Based on dental X-ray photographs (Fig. 4) and periodontal disease examination(Fig. 5), the distal root of the mandibular right second molar was fitted with a coping type of magneticattachment (Fig. 6) in consideration of its load-bearing capacity as an abutment tooth, and we decided tofabricate an extracoronal magnetic attachment using an EC Keeper Tray (GC, Japan) for the mandibular
right first and second premolars (Figs. 7 and 8).

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Fig. 4 X-ray photographs at the first visit                      

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Fig. 5 Periodontal disease examination at the firstvisit

Fig. 6 Coping typeof magnetic attachment

Fig. 7 Extracoronalmagnetic attachment

Fig. 8 EC Keeper Tray

After fixing the coping type of magnetic attachment to the oral cavity, the pick-up impression wastaken in the oral cavity for making a working model, and a framework of the denture was fabricated on it(Fig. 9). The definitive denture had the first molar as a homemade metal tooth, taking into account thespace of the housing portion of the extracoronal magnetic attachment, and the second molar as a hardresin tooth (SR-Orthosit-PE, Ivoclar-Vivadent AG, Liechtenstein) (Fig. 10). In addition, GIGAUSS (GC)was used for a magnetic attachment (the coping type was the D400, and the D600 was applied to theextracoronal attachment).

Fig. 9 Pick-up impression and denture framework

Fig. 10 Definitive denture

Conclusion
Magnetic attachments can be used as support teeth by reducing the lateral pressure as coping types,
even if the remaining teeth have problems with the crown-to-root ratio due to the absorption of alveolarbone. In addition, if the crown-to-root ratio is good, it is possible to produce highly stable dentures byhaving the abutment teeth carry the retention force and bracing force as an external type of crown (Fig.
11).2) In this case, we applied these advantages and produced a denture. As a result, OHIP-14, which isrelated to QOL, was 0 points of the minimum value. By analyzing the amount of glucose dischargeduring gumi-jelly chewing, mandibular movements were quantitatively evaluated to be 188 mg/dl.
Therefore, we were able to produce a prosthesis device that could maintain and improve “Syoku-Riki”(Fig. 12). We plan to confirm the postoperative course while performing regular maintenance in thefuture.

Fig. 11 Intraoral view of treatment procedures

References
1.
2.

S. Ohkawa: For contribution to extension of healthy life expectancy, Ann. Jpn. Prosthodont. Soc, 11,
117–178, 2019.
Y. Tanaka: SHIN JISEI ATATCHIMENTO (New Dental Magnetic Attachment). ISHIYAKUPUBLISHERS INC, Tokyo, 2016.