Long-term follow-up cases of magnetic attachment denture withdifferent prosthetic designs
H. Kumano, Y. Nakamura, H. Nakamura, R. Kanbara, T. Masuda, W. Fujinami, S. Ozawa andJ. Takebe.
Department of Removable Prosthodontics, School of Dentistry, Aichi Gakuin UniversityIntroduction
The magnetic attachments can be small and powerful attractive force by using a neodymium magnet
which is one of rare earth magnets. This system can be used as abutment teeth by decreasing the lateralforce even if crow-root ratio is poor. Therefore, the clinical efficacies of a magnetic attachment havebeen widely demonstrated1,2). The most important advantage of the magnetic attachment is that it canbe used in the root cap type or MT (Magno telescopic) crown type according to the clinical conditionsof the abutment tooth. As a result, it is possible to preserve abutment teeth with maximized support
ability by using either type of them, which is considered to have great clinical advantage. This report
is a case study of partial denture prosthesis designed with magnetic attachments of the MT (Magnotelescopic) crown type for the maxilla and the root cap type for the mandible, which are followed ingood condition for a long time.

Summary of the case
Patient is a 71-year-old woman. The chiefcomplaint was to look better, worry about the bite,and not be able to bite things.
Medical history was hypothyroidism. Historyof present illness was stained teeth, misalignmentof the bite, difficulty in biting, and pain in TMJ.
After splint treatment at the previous doctor, theTMJ problem was improved. However, in May
2007, the patient requested mastication andFig.1 Intraoral views and mandibular removableaesthetic treatment and thus consulted thepartial denture at the time of initial examination
department.
In the present illness, many restorations set on
the remaining teeth in the maxilla and gingival recession at themargin was observed. In the mandible, as well as in the maxilla,
all remaining teeth except for the residual root were set withrestorations. 35 of the intermediate defect was set with the fixed
partial denture incorporating a bar-type retainer.45 was a residualroot and 46,47 was distal extension missing. The facing ofrestorations that had been set was discolored. Mandibular tours
was found on the lingual of the mandible. In addition, when theFig.2 Panoramic radiographs
removable partial denture was set, it was observed the bite raisingat the time of initial(Fig.1).
examination
From panoramic radiographs at the time of initial examination,
radiolucency at the apex was observed in 25, 27 and 36, and poor root canal filling was observed in
16 and 26. Poor crown-root ratio was observed in the mandibular anterior teeth region. In addition,
incompatibility of the restorations in the maxillary and mandibular molars was observed (Fig.2).
Based on the above findings, it was diagnosed as masticatory disorder due to mandibular molar
defect and esthetic disorder due to discoloration of the facing of the maxillary and mandibular fixedpartial dentures.

Treatment and progress
Using the occlusal vertical dimension of the old denture as areference, the study cast was mounted on a semi adjustable
articulator and examined. The presence of the vomiting reflex wasfound in the maxilla during the taking of preliminary impression.
Imaging examination using panoramic radiographs showed apoor crown-root ratio in the remaining mandibular teeth. Then, it
Fig.3 The design of thewas decided to remove all prosthesis for remaining teeth of thedefinitive prosthesis
mandible and to make treatment denture of overdenture type.
Before making the treatment denture, we had to remove themandibular torus that was thought to cause pain when wearing thedenture. Next, the poor prosthesis for the remaining mandibular
teeth were removed and treatment denture was set. The maxilla,
as well as the mandible, were also set with a provisional bridge
after the poor prosthesis were removed. While adjusting theinterim prosthesis set on the maxilla and mandible, re-root canaltreatment was performed for 15,16,26,27,36,45. 36 of the distalroot was treated with hemi section because of poor prognosis.
Fig.4 Panoramic radiographs
After re-root canal treatment, the definitive prosthesis wasof the inner crown of the MT
designed (Fig.3). The design of the definitive prosthesis for thecrown and root cap withmaxilla was a removable dental prosthesis with MT (Magnokeeper (2011.8)
telescopic) crown type using magnetic attachments for theretainer, because the clinical condition of the abutment teeth was good. The reason for making it aremovable dental prosthesis was to consider how
to deal with 13 defects and the vomiting reflex.
In the mandible, considering the clinicalcondition of the abutment teeth and the crownroot ratio, the overdenture was made with a root
cap with keeper as the retainer.
After taking precise impression of the maxillary
and mandibular abutment teeth, the inner crownof the MT crown and the root cap with keeper
were made. After making the inner crown of theMT crown in the maxilla, pickup impression wastaken and the outer crown of the MT crown wasmade. Then, according to the conventional
Fig.5 Intraoral view of the definitive prosthesis
method, the maxillary and maxillary definitiveand placement (2011.8)
prosthesis was made (Fig.4,5). In the maxilla, themagnet assembly was set at the time of placement of the definitive prosthesis. In the mandible, onemonth after the definitive prosthesis was set in place, a magnetic assembly was set on the abutment
tooth after checking that there was no pain in the mandibular residual mucous membrane. The fit ofthe definitive prosthesis was good, and the patient was satisfied both functionally and aesthetically.
After that, it was recalled once every three months.
However, one year and three months after the definitive prosthesis was set in place, mobility of teeth
45 and 36, which were of uncertain prognosis, increased. Therefore, it was diagnosed that it wasdifficult to preserve them, and the teeth were extracted. After healing of the extraction socket, metal
plate denture with the two-piece artificial resin tooth was made to improve the rigidity of the dentureand to maintain the stable occlusal relationship(Fig.6). To obtain an occlusal surface in harmony
with jaw movement, the two-piece artificial resin
tooth was used for about two months. Then, theocclusal surface was replaced with lithium
disilicate glass ceramics.
After the metal plate denture was set in themandible, it was recalled regularly every sixmonths. The purpose of the recall is to manage
Fig.6 Intraoral view and the prosthesis forthe periodontal disease of the remaining teeth
maxilla and mandible (2013.7)
and to check and adjust the occlusal changes ofthe denture and remaining teeth. At present, thedentures and remaining teeth are in good condition (Fig.7,8,9,10).

2015.2

2019.22017.32021.6

Fig.8 Panoramic radiographs ofthe current condition (2021.12)

Fig.7 Periodontal conditions

Fig.9 Intraoral view of the prosthesis formaxilla and mandible and placement (2017.6)

Fig.10 Intraoral view of the prosthesis formaxilla and mandible and placement (2021.6)

Conclusions
This time, MT (Magno telescopic) crown type was selected for the retainer in the maxilla, where
the clinical conditions of the abutment teeth were relatively good. Since the clinical conditions of theabutment teeth were poor, a root cap type was selected for the retainer in the mandible. Finally, thepartial denture prosthesis was designed using different methods of magnetic attachments in the maxilla
and mandible.
The most important advantage of the magnetic attachment is that it can be used in the root cap typeor MT crown type according to the clinical conditions of the abutment tooth. As a result, it is possible
to preserve abutment teeth with maximized support ability by using either type of them, which isconsidered to have great clinical advantage. Therefore, it is considered that this case had a good long-term, functional and aesthetic follow-up. The maintenance of the dentures and remaining teeth will be
continued with the main purpose of checking and adjusting the occlusal changes.

References
1. Tanaka Y. New Magnetic Attachment –New Prosthetic Treatment using magnets-.1st Ed. Tokyo:Ishiyaku Publishers Inc; 2016.
2.Tanaka Y, Nakamura Y, Hoshiai K. General remarks concerning magnetic attachments in dentistry.
Proc Japan Acad; 78(5): 97-105,2002.