JPH06169936A - Magnetic type denture-maintaining apparatus - Google Patents

Abstract

PURPOSE:To obtain a magnet assembly with a size so as to be embedded into a vertical void and a parallel void with a sufficient room by setting the diameter and a thickness of the magnetic assembly at specified values in a magnetic type denture-maintaining apparatus which maintains the denture by a magnetic attraction. CONSTITUTION:In this magnetic type denture-maintaining apparatus which maintains a denture by a magnetic attraction obtained with a magnet assembly buried into a denture tight on a keeper comprising a magnetic alloy fastened on a root plate facing the assembly, the diameter of the magnet assembly is set at 3.6mm-4.3mm while the thickness thereof at 1.0mm-2.0mm. The magnet assembly has a permanent magnet 1, a case comprising an anticorrosive magnetic material having a recess part for housing the magnet 1 and a seal plate 4 comprising an anticorrosive material to cover so that the permanent magnet 1 is not exposed from an opening of the recess part of the case. The outer diameter of the permanent magnet 1 is 2.8mm-3.3mm and the thickness 0.5mm-1.5mm. A force necessary to vertically separate the magnet from the keeper is 350g-650g when the keeper gets light on the magnet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a permanent magnet assembly for use in a prosthetic method for maintaining a denture by utilizing a magnetic attraction force of a permanent magnet.

[0002]

2. Description of the Related Art Various attempts have already been made to use an attractive force acting between a permanent magnet and a soft magnetic alloy to fix a denture, and examples thereof include, for example, "Hiroshi Mizutani, Minoru Ai: Magnetic Attachment-Clinical Application Method Utilizing Its Characteristics-Quatense of Dental Technology, Vol. 16 (1991) December issue, 91-102
Page ". In order to put this kind of denture into practical use, it is necessary that the permanent magnet be completely sealed in a material that is harmless to the human body and that magnetic flux leakage to the outside is small. Permanent magnet assemblies of the construction shown in Figure 2 have been used. FIG. 2 is a view showing a cross section of the permanent magnet assembly. A cylindrical rare earth cobalt magnet 1 magnetized in the axial direction as shown by an arrow is put in a bottomed cylindrical case 2 having a concave cross section made of a stainless alloy having excellent corrosion resistance and magnetism. A seal ring 3 and a seal plate 4 made of corrosion-resistant magnetic stainless steel are covered with a shield plate 5 composed of two kinds of parts, and the abutting portions of these parts are spot-welded with a laser to form a closed structure. It is a permanent magnet assembly. Such a permanent magnet assembly is used for fixing a denture as shown in FIG. 3, for example. That is,
The magnet assembly including the magnet 1, the case 2 and the seal plate 4 is embedded in the denture base 8. On the other hand, the root surface member 7 made of a soft magnetic alloy is embedded in the tooth root 9. Next, as shown in the figure, when the denture is placed so that the seal plate 4 side of the magnet assembly faces the root member 7, a magnetic attraction force acts between the magnet assembly and the root member. To do. Due to this suction force, the denture base 8 is pressed against the root surface member 7 and serves to fix the denture. At this time, the magnetic flux emitted from the magnet 1 passes through the magnetic path consisting of the path of the magnet 1, the root member 7, the case 2, and the magnet 1, so that the leakage magnetic field to the outside is extremely small. Further, since the case 2, the seal plate 4 and the like are made of a stainless material, the corrosion resistance and the wear resistance against the meshing force when fixing the denture are sufficient for practical use and are considered to be practical. .

[0003]

However, the present inventors have found that the permanent magnet assembly having the above-mentioned structure has the following problems. That is, in the magnet assembly, as shown in FIG. 4, the denture base 7 and the artificial tooth 10 are arranged as dentures in a space corresponding to a crown portion which was a natural tooth. Moreover, the magnet assembly 11 is embedded in the denture base 8.
In the case of the molar portion shown in FIG. 3, the vertical gap h between the root surface member 7 and the opposing tooth is about 4.0 mm, and the parallel gap is about the minimum distance d of the tooth diameter portion. It is 5.5 mm. Currently, a magnet assembly having a diameter of about 4.0 mm and a thickness of 2.1 mm is used as a magnet assembly having a size as small as possible while keeping the attraction force at 250 g or more in such a limited space. However, in many cases, the size of this magnet assembly sticks out from the denture base, and even if it is barely able to be embedded in the denture base, the denture base will be thin, so that the magnet assembly will be removed from the place where it is embedded. There was a problem that the denture base was damaged. SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems in the prior art and to provide a magnet assembly of a size that can be embedded in the vertical gap h and the parallel gap d with a sufficient margin.

[0004]

In order to achieve the above object, the present invention has a magnet assembly having a diameter of 3.6 mm to 4.3 m.
m and the thickness was 1.0 mm to 2.0 mm. Further, a samarium or cobalt rare earth magnet or a Fe—Nd—B rare earth magnet is selected as a permanent magnet to be housed in the magnet assembly, and the dimension thereof is a diameter of 2.8 mm to 3.3 m.
m, and the thickness was limited to 0.5 mm to 1.5 mm. As for the maintenance force of the denture, it usually uses two sets of the magnet assembly and the keeper of the keeper, and it is at least 700 for molars.
g or more, and therefore 350 g or more for one set. In addition, although a defective bone grafting tooth, which is a feature of the magnetic denture maintenance device, can be used as an abutment tooth, if the suction force is too large, a force is applied in the direction of pulling the root when the denture is attached and detached, and it has been used for many years. In addition, since there is a concern that defective bone graft teeth may come off, the suction force for one set was set to 650 g or less. In consideration of corrosion resistance, Case 2 and the seal plate are made of Cr:
18-30 wt%, Mo: 1-2 wt%, bal: Fe
Corrosion resistant magnetic stainless steel consisting of In addition,
The seal ring is SUS3 which is a corrosion resistant magnetic stainless steel
16b was used.

[0005]

EXAMPLES The present invention will be described in detail below with reference to examples. (Embodiment 1) FIG. 1 is an explanatory view showing an example of the present invention. Residual magnetic flux density Br = 9 KOe, coercive force iHc = 16
The Sm-Co magnet 1 of KOe has a diameter D2 = 3.20 mm,
The thickness H2 was processed to 0.8 mm, magnetized in the direction of the arrow, and Fe: 68 wt% -Cr-: 30 wt% -Mo: 2.
Outer diameter D1 = 4.0 mm, thickness H1 whose main component is wt%
= 1.5mm, insert into case 2, then thickness 0.2
A SUS316b mm seal ring 3 is fitted with a seal plate 4 made of the same material as the case, and the shield plate 5 is covered. Note that G = 0.2 mm. The butt joint between the case 2 and the shield plate 5 and the mating joint between the seal ring 3 and the seal plate 4 which occur in this assembled state are spot welded by laser. The spot welds are indicated by 6.
After bead removal polishing, diameter of the same material as Case 2.
When a keeper having a thickness of 0 mm and a thickness of 1.0 mm was attracted to the magnet assembly, and the force for vertically separating the keeper was defined as the attraction force, the force was measured and the attraction force was 360 g. In this embodiment, when D1 = 4.4 mm and D2 = 2.7 mm, the suction force is 350 g or less, which is outside the scope of the present invention.
If D1 = 3.6 mm and D2 = 3.4 mm,
This is outside the scope of the invention because the magnetic flux leakage increases and the attraction force becomes 350 g or less. Further, in this embodiment, H1 = 2.0 m
When m and H2 = 1.6 mm, the suction force is 350 g or less, which is outside the scope of the present invention. If H2 = 0.40 mm, the strength of the magnet is weak when the magnet assembly is assembled,
Since chipping and damage became large and the defect rate rapidly increased, it was excluded from the present invention. H1 = 0.9m at H2 = 0.5mm
In the case of m, the leakage magnetic flux is large and the attractive force is 350 g or less, which is outside the scope of the present invention.

(Embodiment 2) In FIG. 1, Sm-C with residual magnetic flux density Br = 9 KOe and coercive force iHc = 16 KOe.
o The magnet 1 has a diameter D2 = 3.20 mm and a thickness H2 = 0.8.
processed into mm and magnetized in the direction of the arrow, Fe: 80 wt
% -Cr: 18 wt% -Mo: 2 wt% as a main component. It is inserted into the case 2 having an outer diameter D1 = 4.0 mm and a thickness H1 = 1.5 mm, and then, a SUS31 having a thickness of 0.2 mm.
A seal plate 3 made of the same material as the case is fitted to the seal ring 3 of 6b, and the lid is covered with a shield plate 5.
Note that G = 0.2 mm. The butt joint between the case 2 and the shield plate 5 and the mating joint between the seal ring 3 and the seal plate 4 which occur in this assembled state are spot welded by laser. The spot welds are indicated by 6. After beating and polishing, a keeper made of the same material as the case 2 and having a diameter of 4.0 mm and a thickness of 1.0 mm was attracted to the magnet assembly, and the force for vertically separating the keeper was defined as the attraction force and measured. However, the suction force was 460 g. In this embodiment, D
If 1 = 4.4 mm and D2 = 2.7 mm, the suction force is 3
It is less than 50 g, which is outside the scope of the present invention. Also, D1 =
When D2 = 3.4 mm at 3.6 mm, the leakage magnetic flux increases and the attractive force becomes 350 g or less, which is outside the scope of the invention. Further, in this embodiment, H1 = 2.0 mm, H2 = 1.
When it is 6 mm, the suction force is 350 g or less, which is outside the scope of the present invention. Further, when H2 = 0.40 mm, the strength of the magnet is weak at the time of assembling the magnet assembly, chipping or damage becomes large, and the defective rate rapidly increases.
When H2 = 0.5 mm and H1 = 0.9 mm, the leakage magnetic flux is large and the attraction force is 350 g or less, which is outside the scope of the present invention.

(Embodiment 3) In FIG. 1, Nd- with residual magnetic flux density Br = 12 KOe and coercive force iHc = 15 KOe.
The Fe-B magnet 1 has a diameter D2 = 3.20 mm and a thickness H2 =
Processed to 0.8 mm, magnetized in the direction of the arrow, and Fe: 6
The main component is 8 wt% -Cr: 30 wt% -Mo: 2 wt%. Outer diameter D1 = 4.0 mm, thickness H1 = 1.5 mm
Insert it into Case 2 and then insert 0.2 mm thick SUS
The seal ring 3 of 316b is fitted with a seal plate 4 made of the same material as the case, and the lid is covered with a shield plate 5. Note that G = 0.2 mm. The butt joint between the case 2 and the shield plate 5 and the mating joint between the seal ring 3 and the seal plate 4 which occur in this assembled state are spot welded by laser. The spot welds are indicated by 6. After beating and polishing, a keeper made of the same material as the case 2 and having a diameter of 4.0 mm and a thickness of 1.0 mm was attracted to the magnet assembly, and the force for vertically separating the keeper was defined as the attraction force and measured. However, the suction force was 450 g. In this example,
When D1 = 4.4 mm and D2 = 2.7 mm, the suction force is 350 g or less, which is outside the scope of the present invention. Also, D1
= 3.6 mm and D2 = 3.4 mm, the leakage magnetic flux increases and the attraction force becomes 350 g or less, which is outside the scope of the invention. Further, in this embodiment, H1 = 2.0 mm, H2 =
If it is 1.6 mm, the suction force is 350 g or less, which is outside the scope of the present invention. Further, when H2 = 0.40 mm, the strength of the magnet is weak at the time of assembling the magnet assembly, chipping or damage becomes large, and the defective rate rapidly increases. When H2 = 0.5 mm and H1 = 0.9 mm, the leakage magnetic flux is large and the attraction force is 350 g or less, which is outside the scope of the present invention.

(Embodiment 4) In FIG. 1, Nd- with residual magnetic flux density Br = 12 KOe and coercive force iHc = 15 KOe.
The Fe-B magnet 1 has a diameter D2 = 3.20 mm and a thickness H2 =
Processed to 0.8 mm, magnetized in the direction of the arrow, and Fe: 8
The main component is 0 wt% -Cr: 18 wt% -Mo: 2 wt%. Outer diameter D1 = 4.0 mm, thickness H1 = 1.5 mm
Insert it into Case 2 and then insert 0.2 mm thick SUS
The seal ring 3 of 316b is fitted with a seal plate 4 made of the same material as the case, and the lid is covered with a shield plate 5. Note that G = 0.2 mm. The butt joint between the case 2 and the shield plate 5 and the mating joint between the seal ring 3 and the seal plate 4 which occur in this assembled state are spot welded by laser. The spot welds are indicated by 6. After beating and polishing, a keeper made of the same material as the case 2 and having a diameter of 4.0 mm and a thickness of 1.0 mm was attracted to the magnet assembly, and the force for vertically separating the keeper was defined as the attraction force and measured. However, the suction force was 640 g. In this example,
When D1 = 4.4 mm and D2 = 2.7 mm, the suction force is 350 g or less, which is outside the scope of the present invention. Also, D1
= 3.6 mm and D2 = 3.4 mm, the leakage magnetic flux increases and the attraction force becomes 350 g or less, which is outside the scope of the invention. Further, in this embodiment, H1 = 2.0 mm, H2 =
If it is 1.6 mm, the suction force is 350 g or less, which is outside the scope of the present invention. Further, when H2 = 0.40 mm, the strength of the magnet is weak at the time of assembling the magnet assembly, chipping or damage becomes large, and the defective rate rapidly increases. When H2 = 0.5 mm and H1 = 0.9 mm, the leakage magnetic flux is large and the attraction force is 350 g or less, which is outside the scope of the present invention. As described above, in any of the examples, when H1 = 2.1 mm or more in FIG. 1, the magnet assembly contains most of the vertical voids shown in FIG. 4, so that the denture base becomes thin. The denture was often broken, so it was excluded from the present invention. Further, if H1 = 0.9 mm or less, H2 needs to have a thickness of at least 0.5 mm from the viewpoint of strength. Considering H3 = 0.2 mm, the bottom thickness of the case becomes thin and the leakage magnetic flux is large. Because the suction power is 350g
Since it is not possible to obtain the above, H1 = 2.0 mm or more.

[0009]

As described above, according to the present invention, the size of the magnet assembly to be embedded through the denture base in the limited space where the crown of the anterior tooth is missing is reduced, and the magnet is Since the suction force of the assembly and the keeper was also sufficiently satisfied as a force for maintaining the denture, the denture is unlikely to break,
A magnetic denture maintenance device could be provided.

[Brief description of drawings]

FIG. 1 is a schematic sectional configuration diagram showing an embodiment of the present invention.

FIG. 2 is a sectional view of a conventional magnet assembly.

FIG. 3 is an explanatory diagram showing an example of a method of using the magnetic denture maintenance device of the present invention to fix a denture.

FIG. 4 is a cross-sectional view for explaining a space required when a magnet assembly is embedded in a molar portion.

Claims (3)

[Claims] 1. A magnetic type for maintaining a denture by a magnetic attraction force obtained by closely contacting a magnet assembly embedded in the denture and a keeper made of a magnetic alloy fixed to a root plate facing the magnet assembly. In the denture maintenance device, the magnet assembly has a diameter of 3.6 mm to 4.3 mm and a thickness of 1.0 mm.
A magnetic denture maintenance device characterized in that it is ˜2.0 mm. 2. The magnet assembly comprises a case made of a corrosion-resistant magnetic material having a permanent magnet and a recess for accommodating the magnet,
A seal plate made of a corrosion-resistant material is provided to cover the permanent magnet from the opening of the case recess so as not to be exposed. The permanent magnet has an outer diameter of 2.8 mm to 3.3 mm and a thickness of 0.
It is 5 m-1.5 mm, The magnetic denture maintenance device of Claim 1 characterized by the above-mentioned. 3. A magnetic denture retainer characterized in that the absorption force is 350 g to 650 g, when the force required to vertically separate the magnet assembly and the keeper in close contact is the absorption force. apparatus.