JPH0984807A - Dental magnetic attraction instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep and fix prosthesis in the oral cavity by attraction force by constituting a dental magnetic attraction instrument of a permanent magnet obtained by directly forming an alloy consisting of a specific ratio of Pt and the remainder of Fe into the shape of dental prosthesis by dental precise castining and a corrosion-resistant magnetic material. SOLUTION: Dental prosthesis 1 is obtained by melting a parmanent magnetic alloy consisting of 33-47% of Pt and the remainder of Fe, desirably, 35-39.9% of Pt and the remainder of Fe or a permanent magnetic alloy consisting of Fe and a small amt. of impurities by a high frequency furnace or an arc melting furnace and casting the molten alloy into a dental embedding material (casting mold) by dental precise casting technique. The surface of the obtained cast lump is finished by grinding and the ground lump is subjected to various heat treatments in order to enhance magnet characteristics to be magnetized. This dental prosthesis 1 is closely bonded to an inner crown 3 bonded to a dental root 4 and made of a highly corrosion-resistant magnetic material and kept and fixed by utilizing the attraction force between both of them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for the prosthesis of a dentition having a missing tooth, and is made of a Fe-type which is directly precision-cast into the shape of a dental prosthesis.
The present invention relates to a magnetic attraction device for dental use which is composed of a Pt-based highly corrosion-resistant permanent magnet and a highly corrosion-resistant magnetic material, and which maintains and fixes the prosthesis in the oral cavity by a suction force acting between the two.

[0002]

2. Description of the Related Art Conventionally, among dental prosthesis retainers, a cylinder type retainer belonging to a double crown system has a structure in which a denture is fixed by a frictional force, so that it is necessary to accurately maintain its dimensions. However, the maintenance force is extremely reduced due to the wear of the material accompanying the extension of the wearing period. The Cornus Krone type retainer, which has improved the disadvantages of the cylinder type, has a conical outer crown and inner crown, and is powerful when the coronus angle (conical inclination angle) of multiple retainers is accurately formed by advanced dental technology. However, if the contact area between the two is small or the material is worn, the maintaining power in the oral cavity becomes unstable. Therefore, it has been attempted to apply a magnetic attachment using an Sm-Co-based or Nd-Fe-B-based magnet in order to increase the maintenance and fixing force of the denture.

[0003]

However, the above Sm-Co or Nd-Fe-B rare earth magnets are inferior in corrosion resistance, and it is necessary to have a closed structure such as a stainless thin plate for use in the oral cavity. Therefore, there is a limit to miniaturization of attachments. As a result, problems such as excessive grinding of healthy teeth that maintain or support the attachment and insufficient storage in the prosthesis space occur. In addition, since the magnet is denatured or demagnetized by heat during brazing or casting, it is in principle necessary to use a non-heated adhesive, and the ability to maintain the dental adhesive also poses a problem.

Since the conventional magnetic attachment has a limited outer shape and magnetizing direction, it is difficult to adapt it to the shape of a crown or bridge, and as a result, it is impossible to select the direction in which the optimum attractive force can be obtained. There was a problem. Further, even if there is a dimensional margin, there is a drawback that the mechanical strength of the crown bridge main body is lowered by embedding the magnetic attachment.

Further, even in the double crown system itself which is currently used, it is difficult for the cylinder type to obtain a proper frictional force at a constant level, and for the Cornus type, there are variations in the maintenance force and wear when a plurality of systems are combined. There is a problem basically caused by dimensional accuracy, such as a decrease in maintenance power due to. Therefore, it is a very time-consuming and economically disadvantageous method to machine a double-crown system that requires a high processing technique from a bulk Fe—Pt-based permanent magnet alloy by machining. For the same reason,
It is also impractical to fabricate dentures, such as partial dentures or removable bridge dentures, by machining.

[0006]

In order to solve the above problems, the present inventors have focused their attention on Fe—Pt type permanent magnet alloys having excellent corrosion resistance, and have focused on dental prostheses such as double crown outer crowns and crowns. , The bridge, the denture itself, etc. invented a dental magnetic attraction device composed of a permanent magnet. That is, in the present invention, Pt 33 to 47
% And the balance Fe, preferably Pt35-3
A permanent magnet alloy consisting of 9.9% and the balance Fe, or Pt 33 to 47%, preferably Pt 35 to 39.9% as a main component, and Ti, V, Cr, Nb, M as a minor component.
10% or less of each of o, Ta, W, Al, Ga, G
e, Rh, Pd, Ir, Au, 7% or less of each, one or two or more of 0.001 to 20% in total, and a permanent magnet alloy consisting of the balance Fe and a small amount of impurities in a high frequency furnace or an arc melting furnace. Dental investment material (mold) formed into molten metal and formed into the shape of the dental prosthesis described above.
It is cast by dental precision casting technology that applies pressure casting, centrifugal casting or suction casting. Steam, air or various gases are used as a pressure source in the compression casting, but the use of an inert gas such as Ar has an advantage that the oxidation of the sample can be suppressed. For the same reason, when centrifugal casting or suction casting is applied, it is desirable to operate in an inert gas atmosphere or vacuum. The investment materials used in the dental precision casting method include phosphate-based and gypsum-based investment materials, whose main component of the refractory material is silica, and high melting points, depending on the volume, shape and type of the dental prosthesis to be cast. A cement-based investment material for alloys, an ethylsilicate-based investment material, or a non-silica-based investment material such as a magnesia-based, zirconia-based, or alumina-based investment material is used. These are molded into a shape of a dental prosthesis by the lost wax method or the like, dried at a temperature of room temperature to 1200 ° C., baked, and then used as a casting mold. The surface of the ingot thus obtained is finished by polishing or the like, and various heat treatments are performed to improve the magnet characteristics, and then magnetized. The dental prosthesis finished in this way is bonded to the tooth root side with a highly corrosion-resistant magnetic material, such as magnetic stainless steel, a soft magnetic material, or a dental Pd-Co-Ni magnetic alloy, or a highly corrosion-resistant permanent magnet ( Fe-Pt magnet alloy, Fe-Pd magnet alloy, Alnico magnet alloy, Co-
Pt-based magnet alloy, etc.)
The prosthesis is maintained and fixed by utilizing the suction force between the two. The features of the present invention are as follows.

The first invention is Pt 33-47% in atomic ratio.
The present invention also relates to a magnetic attraction device for dental use, which comprises a permanent magnet and a corrosion-resistant magnetic material obtained by directly precision-casting an alloy containing the balance Fe and a small amount of impurities into the shape of a dental prosthesis.

The second invention is that the atomic ratio of Pt is 33 to 47%.
As a main component and Ti, V, Cr, Nb, M as sub-components
10% or less of each of o, Ta, W, Al, Ga, G
e, Rh, Pd, Ir, Au, 7% or less of each, 1 or 2 or more, 0.001 to 20% in total, and an alloy consisting of the balance Fe and a small amount of impurities, directly into the shape of a dental prosthesis by dental precision casting. The present invention relates to a dental magnetic attraction device comprising a permanent magnet and a corrosion-resistant magnetic material.

A third aspect of the present invention relates to the dental magnetic attraction device of the first aspect or the second aspect, wherein the dental prosthesis is a denture.

A fourth aspect of the present invention relates to the dental magnetic attraction device of the first aspect or the second aspect, wherein the dental prosthesis is a double crown outer crown.

According to a fifth aspect of the present invention, the occlusal surface and the side wall portion of the denture or double crown outer crown are surface-divided into two or more pieces independently or continuously between the two, and each portion is an N pole or an S pole. The present invention relates to the dental magnetic attraction device according to the third invention or the fourth invention, characterized in that it is composed of a magnetized permanent magnet.

According to a sixth aspect of the present invention, a permanent magnet magnet is divided into two or more parts by a groove formed in the inner surface of the outer crown of a denture or a double crown, and each part is magnetized into an N pole or an S pole. The present invention relates to the dental magnetic attraction device according to the third invention or the fourth invention.

[0013]

The structure of the present invention will be described below. The components of the permanent magnet alloy are 33 to 47% Pt and the balance F in atomic ratio.
e, preferably an alloy of Pt 35 to 39.9% and the balance Fe, or Pt 33 to 47%, preferably Pt 35 to 39.9% as a main component, and Ti, V, Cr, Nb, Mo as a minor component. , Ta, W 10 each
% Or less, and Al, Ga, Ge, Rh, Pd, Ir, and Au each of 7% or less, one kind or two or more kinds in total.
001 to 20% and the balance Fe and a small amount of impurities. These alloys are cast into an investment material by a dental precision casting method in which a gas compression casting machine, a centrifugal casting machine, or the like is installed in a high-frequency furnace, an arc furnace, or the like. This makes it possible to manufacture a dental prosthesis such as a crown or a bridge, which requires a complicated shape and accurate dimensional accuracy, without using mechanical processing. This is a great advantage of the casting method of the present invention. In order to obtain good magnet characteristics in this alloy with a high melting point and composition sensitivity in magnetic characteristics, a high-frequency furnace in which the molten metal is uniformly heated and agitated efficiently is used. About twice as fast as the casting method 0.1
~ 0.2 seconds casting time and 4 times higher 2kg / cm ²
The gas pressure casting method, which allows casting at a high pressure, is suitable. As for the investment material, a phosphate-based, cement-based or magnesia-based investment material for high temperature is suitable in view of the surface roughness of the casting. Next, in order to improve the magnet characteristics, the obtained ingot is subjected to various heat treatments and then magnetized. The performance of this magnet is, for example, the residual magnetic flux density (Br) 1
0 to 11 kG, coercive force (H _CJ ) 4.5 to 5.0 kOe,
The maximum energy product (BH) _max is comparable to that of 20 to 21 MGOe and Sm-Co magnets, and shows the highest performance of alloy magnets.

The reason why the composition range of the magnet alloy is limited as described above is that when the atomic ratio of Pt is less than 33% and 47% or more, the maximum energy product (BH) _max decreases to 3 MGOe or less and the attractive force is extremely small. This is because a practical maintenance and fixing force cannot be obtained.

Next, Ti, V, Cr, N as sub-components
b, Mo, Ta, W each 10% or less, Al, G
The reason for adding one or two or more of a, Ge, Rh, Pd, Ir, and Au out of 7% or less is that the solution treatment temperature should be included when these are contained in a total amount of 0.001 to 20%. Since the temperature can be lowered by about 200 ° C. from the case of no addition, solution treatment and disordered phase formation of the alloy can be easily performed. Further, the aging heat treatment time for obtaining the magnet characteristics can be shortened to, for example, 10 hours or less even in the longest case, and the variation in the magnet characteristics is reduced. If the amount of the additive element is 0.001% or less, the above effect cannot be obtained,
On the other hand, if it is 20% or more, the original characteristics are adversely affected, the magnet characteristics are deteriorated, and a practical attractive force cannot be obtained.

In the double crown system of both cylinder and cone type, for example, when the outer crown itself is a permanent magnet and the inner crown is a keeper made of a highly corrosion-resistant magnetic material, the tooth size depends on the type and shape. The thickness of the outer crown is within the range of 0.5 to 3 mm and the thickness of the inner crown is within the range of 0.3 to 2 mm. You can get a good suction force. If the thickness of both is further reduced, the suction force generated between them is extremely reduced, and if the thickness of either is increased, the space is limited and the other party becomes relatively thin. Therefore, it is a great feature of the cast magnet according to the present invention that the dimensions of the outer crown and the inner crown can be adjusted according to the situation.

FIG. 1 is a schematic view showing a cross section of a double crown system according to a first embodiment, which is applied to a vital tooth. As for the deactivated tooth, as in the example shown in FIG. 2, a system in which a corrosion-resistant magnetic stainless steel keeper 8 is fixed to the tooth root 4 with a dental adhesive or the like and combined with the outer crown 1 Can be used. Also, the tooth root 4 is T
The artificial tooth root using i or the like may be embedded in the jawbone, in which case the keeper is fixed by an adhesive or a screw or the like provided between the artificial tooth root and the keeper. FIG. 3 is a schematic diagram in the case of manufacturing a removable bridge denture, and FIG. 1 shows a state in which an abutment tooth 10, an inner crown 3 and an outer crown 1 are combined in a vertical section P in the drawing. It is also possible to realize a bridge with an excellent structure that has lateral stability because the base surface can be formed in a saddle shape in addition to cleaning the mouth by making the bridge a removable structure like the artificial tooth 9. This is a feature of the invention.

Magnetization of the outer crown 1 is performed by independently or continuously connecting both the occlusal surface and the side wall portion of the prosthesis, and performing surface division radially from two or more, for example, the center of the occlusal surface. B)
When 4 poles are used and each part is magnetized to the N pole or the S pole, compared to the 2 pole magnetization shown in FIG. It has the advantage that

Further, when applied to a molar having a large dimensional allowance, the inner surface of the magnet constituting the outer crown 1 with respect to the occlusal surface, for example, a width of 0.1 to 0.3 mm radially from the center,
A groove with a depth of 0.2 to 0.5 mm is provided, and the surface is divided into a plurality of parts. By alternately magnetizing the N pole and the S pole respectively, the attraction force is strengthened and the maintenance fixing force is unified. Can be planned. This is because one of the excellent features of the method of the present invention is that the closed magnetic circuit structure is emphasized by the close keeper (inner crown) and a large amount of magnetic flux is confined, resulting in an increase in attractive force.

In the case of the Cornus Krone system shown in FIG. 1, conventionally, the contact surfaces of both the inner and outer crowns are in strong contact with each other, and the upper end surface of the inner crown 3 and the relative surface of the outer crown 1 (the back side of the occlusal surface). Providing a space between them is an important condition. However, with the combination of the present invention, even when the contact force between the two is small and the maintenance force is insufficient, or when the gap is lost due to wear due to long-term mounting, the outer cap is generated by the attraction force of the magnet. Is maintained. In addition, the addition of the suction force eases the conditions of the dental precision casting and the manufacturing conditions such as the Cornus angle range, so that the Cornus Krone system can be easily obtained. Further, it is effective from the viewpoint of occlusal preservation without causing subsidence of the outer crown in the oral cavity.

[0021]

EXAMPLES The present invention will be described below based on examples. Example 1 Pt 39.0%, V1.
5%, the balance Fe alloy ingot (outer diameter 6 mm ×
90 mm long) was cast. Length 4 from this ingot
5 mm was cut out and used as a base material for dental precision casting. The base material is melted in a vacuum using a high-frequency melting furnace, and immediately afterwards, in an Ar gas compression casting machine, in a phosphate-based investment material fired at a temperature of 750 to 850 ° C or in a gypsum-based investment material fired at 650 ° C. Then, an outer coronal test piece having an outer diameter of 7 mm, a minimum inner diameter of 5.0 mm, a height of 6 mm and a thickness of 2 mm on the upper end surface was produced. After subjecting this test piece to solution treatment at 1325 ° C. in vacuum for 30 minutes, the test piece was immersed in cold water to cool, and subsequently 640 ° C. in vacuum.
And heat treated for 15 hours. When the test piece was magnetized with 4 poles shown in FIG. 4 (B) in a pulse magnetic field of 4T (Tesla),
The surface magnetic flux of one pole at the upper end was 3.0 kG. Inner crown is corrosion resistant magnetic stainless steel 26% Cr-1% M
o-The balance Fe alloy SUSXM27 was used to perform precision casting into various shapes with a minimum outer diameter of 5.0 mm, a height of 4 mm, and an upper end surface thickness of 0.5 to 1 mm by using a dental precision casting apparatus, and then the axial surface of 6 to The Cornus angle was adjusted to 8 degrees. Example 1 is composed of the above two points, and the magnet characteristics and the attraction force between the two in this case are shown in Tables 1 and 2. The suction force was measured using a precision tensile tester while the inner crown side was semi-fixed, the outer crown was held by a collet chuck, and the center lines were aligned. For magnet characteristics, a specimen of 2 mm in diameter and 6 mm in length was cut out from the sprue part of the test piece and heat-treated at the same time as the test piece.
M) is a value measured with an external magnetic field of 1T.

[0022]

[Table 1] * For comparison, the attraction force when the outer crown is not magnetized is shown (hereinafter the same).

[0023]

[Table 2]

Example 2 Pt 38.5%, Nb 1.0%, Cr 1.0
%, The balance Fe alloy was used, the melting and casting methods were the same as in Example 1, but the investment material was 750 ° C. and 850 ° C.
A phosphate-based investment material fired at ℃ and a cement-based investment material fired at 1200 ° C were used. This test piece in vacuum 1
After solution treatment at 200 ° C. for 30 minutes, put in a salt bath at 700 ° C. and hold for 5 minutes, then put in cold water to cool,
Then, it heat-processed at 620 degreeC in a vacuum for 5 hours. The magnetization was performed in the same manner as in Example 1 with 4 T pulsed magnetic field. As a result, the surface magnetic flux was 2.9 kG. The inner crown was made of the same material and method as in Example 1. Example 2 is composed of the above two points, and the magnet characteristics and the attraction force between the two in this case are shown in Tables 3 and 4. The dimensions of the sample used for the measurement of the magnet characteristics and the measurement conditions are the same as in Example 1.

[0025]

[Table 3]

[0026]

[Table 4]

Example 3 Pt 39.0%, Au 0.75%, balance Fe alloy was used as the magnet, and the melting, casting method and investment material were the same as in Example 1 and fired at 750 ° C. and 850 ° C. A phosphate-based investment material and a gypsum-based investment material fired at 650 ° C. were used. The test piece was subjected to solution treatment in vacuum at 1325 ° C. for 30 minutes, then put into cold water to cool, and subsequently heat-treated in vacuum at 650 ° C. for 15 hours. The test piece was magnetized in the 4T pulse magnetic field as shown in FIG. As a result, the surface magnetic flux was 2.9 kG. As the inner crown, one produced by using the same material and method as in Example 1 was used. Example 3 is composed of the above two points, and the magnet characteristics and the attraction force between the two in this case are shown in Tables 5 and 6. The dimensions of the sample used for the measurement of the magnet characteristics and the measurement conditions are the same as in Example 1.

[0028]

[Table 5]

[0029]

[Table 6]

[0030]

EFFECTS OF THE INVENTION Conventionally, a dental maintaining fixture such as a double crown system has a retaining force when the gap between the inner crown and the outer crown is lost due to asymmetry of coercive force, instability of retaining force and abrasion. It has the drawback of not working. INDUSTRIAL APPLICABILITY The present invention has a great effect of solving the above-mentioned problems by utilizing the attractive force of the magnet by directly performing precision precision casting of a Fe—Pt-based permanent magnet alloy having excellent corrosion resistance into a dental prosthesis shape for magnetization. . Further, in the present invention, since the permanent magnet and the keeper have a structure such as a double crown system in which they are present in close proximity to each other, a closed magnetic circuit is formed and almost no leakage magnetic flux occurs. Therefore, the detonation amount in the oral cavity is a reference value of 2 kG. It has the effect of significantly reducing it. Therefore, according to the present invention, oral hygiene, maintenance of healthy teeth, maintenance stability of dentures, and other excellent features that cannot be obtained from the application of conventional magnetic attachments, and practical dental maintenance and fixation of dentures are possible. A magnetic attraction device can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a dental magnetic attraction device of the present invention,
3 shows an outer crown combined with an inner crown adhered to the root of a vital tooth.

FIG. 2 is a cross-sectional view when the dental magnetic attraction device of the present invention is applied to a deactivated tooth.

FIG. 3 is a drawing for explaining the situation of the dental magnetic attraction device of the present invention, and the P surface corresponds to the cross-sectional portion shown in FIG.

FIG. 4 is a drawing showing an example of a magnetized state of the dental magnetic attraction device of the present invention. (A) Example of 2-pole magnetization of the outer crown (B) Example of 4-pole magnetization of the outer crown (C) Example of 8-pole magnetization of the outer crown (D) Radiation from the center of the inner surface of the outer crown An example in which the surface is divided by grooves, and each part is magnetized into four poles alternately as N pole and S pole.

[Explanation of symbols]

 1 Permanent magnet outer crown 2 Micro gap 3 Inner crown 4 Tooth root 5 Adhesive surface between inner crown and tooth root (fixed with dental adhesive) 6 Gingiva 7 Jaw bone 8 Keeper made of ferromagnetic material 9 Artificial tooth (pontic) 10 Abutment

Claims (6)

[Claims] 1. An alloy comprising Pt 33 to 47% in atomic ratio and the balance Fe and a small amount of impurities is directly precision precision cast into a shape of a dental prosthesis and is composed of a permanent magnet and a corrosion resistant magnetic material. Dental magnetic attraction device. 2. Atomic ratio of Pt 33-47% as a main component and Ti, V, Cr, Nb, Mo, Ta
10% or less of W, Al, Ga, Ge, Rh, P
1 or 2 out of 7% or less of d, Ir and Au
Dental alloy characterized by comprising a permanent magnet and a corrosion-resistant magnetic material, which are precision-cast directly into the shape of a dental prosthesis, from an alloy consisting of 0.001 to 20% of total species and a balance of Fe and a small amount of impurities. Magnetic attraction device. 3. The dental magnetic attraction device according to claim 1, wherein the dental prosthesis is a denture. 4. The dental magnetic attraction device according to claim 1, wherein the dental prosthesis is a double crown outer crown. 5. The denture or the double crown outer crown has an occlusal surface and a side wall portion which are independently or continuously surface-divided into two or more pieces, and each portion is an N pole or an S pole. The dental magnetic attraction device according to claim 3 or 4, wherein the permanent magnet is magnetized in the permanent magnet. 6. The permanent magnet, wherein the denture or the double crown outer crown is surface-divided into a plurality of two or more pieces by a groove provided on an inner surface thereof, and each portion is magnetized into an N pole or an S pole. It comprises, The dental magnetic attraction apparatus of Claim 3 or Claim 4 characterized by the above-mentioned.