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

A Case of Single Implant Overdenture with Magnetic Attachment
Mitsuki Masumoto, Yasunori Suzuki, Keisuke Kohri, Ryouji Muto, Chikahiro Ohkubo
Department of Oral Rehabilitation and Prosthodontics, Tsurumi University School of Dental Medicine

I. Introduction
Single-implant overdentures (S-IODs) for edentulous mandibular patients can reduce treatment
costs and surgical invasiveness, and relatively high success rates have been reported. In this report, wepresent a case of single imprant retained overdenture with magnetic attachment.

II. Objective
Althopugh the height and width of residual ridge was surficient for two implant overdenture (2IOD), we chose a S-IOD with one implant placed in the midline of mandible because of economic
reasons and less surgical invasion.

III. Case report
1 Patient Information
The patient was a 66-year-old female, presented to our hospital with a chief complaint of broken
dentures and difficulty in chewing. Her remaining teeth were suffering from severe periodontal disease,and anterior crown was removed from maxillary right canine. Her existing denture had been usedapproximately 5 years ago with lots of repairs to denture failure. There were no special notes on her
general history.

Figure 1. Panoramic radiograph at the first examination and computerized tomography

Figure 2. Intraoral views at the first examination

Figure 3. Existing maxillary and mandibularremovable partial dentures[Web Presentation] PS3-1-1

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

2 Treatment Procedures
Since alveolar bone resorption and movement of the maxillary right canine tooth were observed, amaxillary overdenture was selected to improve the crown-root ratio. For mandible, S-IOD was selected
to retain and stabilize the denture after the extraction of the remaining teeth with severe periodontal
disease.
1)

After extraction of the mandibular left lateral incisor and canine, one implant (Standard Plus, 3.3mm×12 mm, Straumann, Basel, Switzerland) was simultaneously placed using surgical guide(Fig.4 and 5).

Figure 4. Placement of one implant

Figure 5. Panoramic radiograph after implant placement
2)

Three weeks after implant placement, the healing abutment was fitted to denture base withautopolynorized resin for early loading (Fig.6). One month after implant placement, a magneticattachment (MagFit, Aichi Steel, Aichi, Japan ; a flat-top type with 750 gf magnetic attractive force)
was replaced from the healing abutment for denture retation (Fig.7).

Figure 6. Early loading was added 3 weeks after implant placement

Figure 7. Placemnet of magnetic attachment3) After magnetic attachment was placed , the definitive impression was made and occlusal[Web Presentation] PS3-1-2

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

relationship was recorded for the mandibular S-IOD using a duplicate denture (Fig.8), a working
cast was fabricated. To record the denture space, Piezography technique was performed to record
the muscle pressure surface using silicone impression material (Exafine , GC, Tokyo, Japan) by thepatient pronounces ¨SIS, SE, SO, TE, DE, MOO, SEES¨ etc, (Fig.9).

Figure 8. Definitive impressions using duplicate denturesFigure 9. Piezography
4)

Denture teeth were arranged and the wax denture was made within the muscle pressure surface
morphology obtained by piezography technique.

5)

RPD with a wire clasp on the left second premolar and resin copings on the right canine wasdeliver for maxillary jaw. For mandiblar jaw, S-IOD with magnetic attachment was also delivered(Fig.10 and 11). The S-IOD was reinforced by a metal structural framework to improve the strengthand rigidity of the denture (Fig.12).

Figure 10. Intraoral view without denture

Figure 11. Placement of final removable denture[Web Presentation] PS3-1-3

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

Figure 12. Completed mandibular S-IOD6)

The definitive denture was fitted without pain. Bilateral balanced occlusion was added to preventthe denture mobility and lateral force to the implant (Fig.13).

Figure 13. Occlusal contacts relationship during lateral movements

IV. Results
The coefficient of variance of masticatory movements was measured using a Biopack(Biopack,Yoshida, Tokyo, Japan). The definitive denture with magnefit attachment showed the stable
masticatory movements in all masticatory phases and cycles compared to the existing denture
without magnetic attachments (Fig.14).

60.0

old denture
Without attachments
With attachment

50.0

40.0

30.0

20.0

10.0

0.0

Aperturephase
開⼝相ClosedMouth Occlusal
phase Mastication
閉⼝相
咬合相
咀嚼周期cycle

Figure 14. Coefficient of variance of masticatory movements
Pre- and postoperative occlusal examination were performed using Dental Prescale I (DentalPrescaleⅠ, GC, Tokyo, Japan). The postoperative occlusal contact area was approximately twicevalues compared to the preoperative area, and the occlusal force was approximately four times larger
than the preoperative one (Fig.15).

[Web Presentation] PS3-1-4

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

Figure 15. Occlusal examination (Left: Preoperative, Right: Postoperative)

V. Discussions
The S-IOD has a single fulcrum point compared to the 2-IOD, which allows more freedom of thedenture movements. The careful maintenance must be necessary compared to the conventional 2-IODs
to prevent the implant lost.

VI. Conclusions
It has been 9 years since the S-IOD was placed, and there has been no significant bone resorption
around the implant, no change of retentive force, and no denture failures, resulting in improved
masticatory efficiency and highly patient satisfaction. The application of magnetic attachments to theS-IODs reduced the lateral pressure to the implants and resulted in a good outcome.

References
1) Walton JN, Glick N, Macentee MI. A randomized clinical trial comparing patient satisfaction
and prosthetic outcomes with mandibular overdentures retained by one or two implants. Int JProsthodont. 2009;22(4):331-9.

[Web Presentation] PS3-1-5