JPH10323357A - Soft cushioned dental magnetic attachment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a soft cushioned dental magnetic attachment with a shock absorbing elastic material member which can be adhered well without requiring such processes as sand blast or primer application, etc., and is separated from the magnetic structure adhered with it even after long time mastication. SOLUTION: This dental magnetic attachment 1 consists of a keeper 3 to be attached inside the mouth cavity and a magnetic structure 2 with a permanent magnet to adsorb the keeper. A covering layer 4 made of thermoplastic synthetic resin is formed at least on the surface of the magnetic structure 2 to receive the pressure of occlusion excluding the contact surface with the keeper. The thermoplastic synthetic resin is at least made of metal adhesive polyolefin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dental magnetic attachment used in the oral cavity. More specifically, the present invention relates to a dental magnetic attachment having gentle pressure used for removable dentures such as full dentures and partial dentures.

[0002]

2. Description of the Related Art When teeth are lost, mastication and the like are impaired, pronunciation is poor, esthetics such as facial appearance are impaired, and gastrointestinal disorders such as indigestion are started.
Or adversely affect physical health. For missing teeth etc., by wearing dentures, chewing,
The pronunciation function can be restored, the aesthetics such as the facial appearance can be improved, and further, health can be maintained. In order to perform good mastication, it is important that the denture can be worn and used in a stable state.

[0003] The denture is mounted on a maintenance device for use. Of the dentures, devices for maintaining partial dentures can be broadly classified into clasps, attachments, and telescope crowns. The clasp is a maintenance device made of metal or the like attached to the remaining teeth. The clasp is relatively easy to manufacture and can adopt various shapes, so it can be manufactured according to the case,
It is versatile and widely used. However, since the clasp is used in contact with the tooth surface of a healthy remaining tooth, it is easy to damage the enamel on the tooth surface, and the tooth surface is brushed on a daily basis to remove plaque and the like. It is necessary to do so, and if this is not done, tooth decay will occur. In the case of the clasp, since the point of attachment to the remaining teeth is relatively high, an excessive lateral force or rotational force is applied to the remaining teeth at the time of mastication, etc., which exceeds the burden capacity of the remaining teeth to the periodontal tissue. This will damage the periodontal tissue. Furthermore, since the tooth surface is covered with metal, the aesthetic appearance is extremely poor, and this is the biggest cause of dislike of dentures by patients.

Attachments and telescope crowns have been used as maintenance devices without the disadvantages of a clasp. As the attachment, for example, a sliding attachment that fits in a female part (female) and a male part (mail), a hinged attachment having a ball socket hinge, a joint type joint attachment that is famous as a Darbo type, There are various types, such as a fixed bar type attachment called a doder bar and an Ackerman. As the telescope crown, the Cornus Krone telescope exists as an established technology.

However, the manufacture of these attachments is complicated. It is said that the occlusal force of a person during mastication is 78 kg on average, and the occlusal pressure during mastication tends to cause damage to the attachment body and damage to the remaining root to which the attachment is attached. In addition, the telescope crown has excellent performance as a maintenance device when the matching accuracy between the inner crown and the outer crown is good, but it requires skill to ensure good matching accuracy, and Since special equipment for manufacturing the telescope crown is required, it is expensive and hardly general. If the inner crown and the outer crown are worn in the oral cavity with poor matching accuracy, a force perpendicular to the remaining root (i.e., a lateral force) acts on the remaining root and adversely affects the remaining root.

In recent years, as an attachment, a magnetic attachment (23) comprising a magnet structure (21) and a keeper (22) as shown in FIG. 3 has been developed and rapidly spread. The magnet structure (21) has a built-in permanent magnet, is embedded in the denture (24) so as to expose the joint surface (21a), and has an abutment tooth (25).
The joining surface (21a) is provided on the surface of a keeper (22) made of a soft magnetic material provided on a root plate (26) embedded in the base plate.
Are magnetically attracted and fixed. The magnet structure (21) attracts by a very strong magnetic force in a direction perpendicular to the keeper (22), but a force parallel to the surface of the keeper (22) and the joint surface (21a), that is, to the denture. When the lateral force acts, the detachment is performed with a relatively weak force, so that the lateral force has little adverse effect on the abutment tooth (25) and the periodontal ligament (27). Therefore, the keeper (2
The joint structure between 2) and the magnet structure (21) does not require as high a precision as a telescope crown, and is easy to manufacture. And the magnetic attachment (23)
The attachment and detachment of the denture is simple and easy to handle, and is extremely aesthetically pleasing.

[0007]

However, the magnetic attachment has the following difficulties in supporting the mastication force. For example, in a partial denture using a magnetic attachment, the load pressure caused by the mastication force applied to the denture during mastication is transmitted to the periodontal ligament tissue through the root plate of the abutment in a part of the maintenance device using the magnetic attachment. It is well controlled reflexively by afferent impulses of baroreceptors in periodontal ligament tissue. At this time, the periodontal ligament tissue is up to about 100 by the vertical pressure due to the mastication force.
２００200 μm. On the other hand, in the part supported by the mucous membrane, the applied pressure due to the mastication force is applied to the alveolar bone via the mucosal tissue under the denture base, and the applied mucosal tissue is compressed by about 1000 μm when the load is large. It is considered that the control of the load pressure in this part is performed by the impulse of the pain receptor in the mucous membrane, and the limit of the pressure load to the load pressure is not necessarily in the harmless range. As described above, the vertical subsidence amount of the periodontal ligament tissue with the maintenance device is about 1/5 to about 1/10 of the denture base mucosal tissue, and the so-called free end in which both the abutment and the mucous membrane share the load. In the case of dentures, appropriate load distribution in the periodontal ligament and mucous membrane of the abutment is extremely important and difficult.

As described above, since the periodontal ligament and the mucous membrane have different responses to the mastication force, that is, the order of the amount of subsidence is different, for example, in the mesial portion of a free denture having a mesial maintenance device. When the mastication force is applied, the majority of the mastication force is transmitted to the periodontal ligament via the maintenance device, and the degree of mucosal support increases as the mastication part moves away from the maintenance device and moves toward the distal end, and a certain amount of subsidence of the denture base causes Tissue support occurs. Therefore, the mucosal tissue under the denture base does not exert an even pressure on the whole in this case, and the load bears on the periodontal ligament of the abutment via the maintenance device. As a result, the periodontal tissue is destroyed due to the overload, and the harmful lever action on the periodontal ligament of the abutment is increased, which is likely to cause the loss of the valuable abutment.

For this reason, in magnetic attachments, attempts have been made to cushion the occlusal pressure on the denture by covering the magnet structure with an elastic cap (see Japanese Patent Application Laid-Open No. 7-246208). this is,
Put the elastic cap on the magnet structure and make it adhere,
This is intended to be embedded in a denture via a cap and to adhere the magnet structure and the keeper on the root side by magnetic force. By this, it becomes possible to buffer the occlusal pressure applied to the denture at the time of mastication, etc.
Large elastic deformation is repeated between the magnet structure and the denture, and due to long-term use, the adhesion between the magnet structure and the resilient cap causes fatigue failure and is likely to be separated. When the adhesion between the magnet structure and the elastic cap is separated, the chewing feeling is deteriorated, or the magnet structure falls off from the denture and remains on the keeper surface. In that case,
If a force parallel to the keeper surface acts on the dropped magnet structure, the magnet structure will easily come off the keeper,
In some cases, it can be accidentally swallowed. Further, even if the magnet structure is successfully removed from the keeper, the magnet structure alone is easily lost.

In order to improve the adhesive strength between the magnet structure and the elastic cap, it is conceivable to sandblast the adhesive-coated surface of the magnet structure or apply a primer to the adhesive-coated surface. After the sand blasting of the magnet structure, the joint surface with the keeper must be mirror-polished, which is troublesome, requires skill, and increases costs. In addition, applying a primer only to the surface of the magnet structure to which the adhesive is applied is troublesome and requires skill because the magnet structure is small. Further, as the adhesive, for example, in a hot-melt adhesive used at a temperature of 200 ° C. or higher, such as a hot melt adhesive or an ethylene copolymer resin adhesive, the magnetic force of the magnet structure is reduced or disappears. It is not preferable.

The present invention has been made as a result of earnest research in view of the above-mentioned circumstances, and an elastic material for absorbing a shock to an abutment tooth caused by a mastication force in a magnet structure of a magnetic attachment. By providing a function, it has the function of rationally distributing the occlusal pressure to the abutment tooth and the chin mucous membrane part,
Provided is a dental magnetic attachment exhibiting good adhesiveness without performing sandblasting treatment or primer application, and having a gentle pressure property such that adhesion to a denture is not impaired by long-term chewing or the like. It is intended to be.

[0012]

In order to solve the above-mentioned problems, the present invention provides a dental magnetic attachment comprising a keeper provided in an oral cavity and a magnet structure having a permanent magnet magnetically attracted to the keeper. The magnet structure is provided with a coating layer made of a thermoplastic synthetic resin on at least a surface that receives an occlusal pressure except for a joining surface with a keeper, and the thermoplastic synthetic resin is at least a metal-adhesive polyolefin. Characterized by the following.

The permanent magnet is preferably a samarium-cobalt-based, neodymium-cobalt-based, or neodymium-iron-boron-based rare earth magnet, but is not limited thereto. These magnets are preferably coated with magnetic stainless steel or the like, but are not limited thereto. By covering these magnets with magnetic stainless steel or the like, contact with saliva or the like is prevented, and elution of rare earth elements or the like into the oral cavity is prevented.

Further, as the thermoplastic synthetic resin, when a magnet structure is embedded in a denture and used, the coating layer made of the thermoplastic synthetic resin provided on the magnet structure has an effect on the periodontal ligament against the mastication force. It is elastically deformed to compensate for the amount of subsidence, making it possible to achieve the same amount of subsidence as the mucous tissue under the denture base as a whole. It is necessary to reduce the leverage of the abutment tooth to the periodontal ligament, maintain the occlusal balance, and do not cause separation at the interface with the magnet structure even by long-term mastication, etc. It is.

A coating layer made of a thermoplastic synthetic resin is bonded and fixed to the magnet structure by the metal adhesive polyolefin in the thermoplastic synthetic resin. The metal-adhesive polyolefin is preferably one obtained by introducing a carboxylic acid into a very low-density polyethylene by a graft reaction.
The mechanism of adhesion between the metal-adhesive polyolefin and the metal is not clear, but causes a chemical bond or a hydrogen bond with the carboxylic acid introduced by the graft reaction and the oxide film on the metal surface or the -OH group in the sorbed moisture. It is thought to be due to this.

By providing the coating layer made of the thermoplastic synthetic resin also on the side surface of the magnet structure, it is possible to respond to the lateral pressure in the horizontal direction. In order to provide a coating layer made of a thermoplastic synthetic resin on at least the surface that receives the occlusal pressure except for the joining surface with the keeper, injection molding and compression molding may be employed.

The thermoplastic synthetic resin may be a metal-adhesive polyolefin alone or a polymer blend containing a metal-adhesive polyolefin.
When the metal synthetic polyolefin alone is used as the thermoplastic synthetic resin, it is preferable to apply a mold release agent to the mold in order to improve the mold releasability after molding. Further, in order to prevent sink marks during molding, the molding speed may be reduced. When using a polymer blend,
As thermoplastic synthetic resins other than the metal-adhesive polyolefin, soft polyethylene such as high-pressure low-density polyethylene (HPLDPE), very low-density polyethylene (VLDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), High density polyethylene (HDP
E), ethylene vinyl alcohol copolymer (PVO)
H), ethylene-vinyl acetate copolymer (EVA), polypropylene (PP), ethylene ionomer, and the like. One or more of these thermoplastic synthetic resins other than the metal-adhesive polyolefin can be polymer-blended with the metal-adhesive polyolefin. The combination of thermoplastic synthetic resins in polymer blends is
It does not alienate the adhesiveness of the metal-adhesive polyolefin to the magnet structure, and takes into account the compatibility and miscibility of the resins, mechanical properties such as elasticity, biocompatibility, releasability and anti-sinking properties. It is determined in consideration of moldability, manufacturing cost, etc. It is necessary to select the mixing ratio in a range where the adhesion to the magnet structure can be sufficiently ensured. In the case where the metal-adhesive polyolefin and another thermoplastic synthetic resin are used in a polymer blend, it is sufficient that the metal-adhesive polyolefin is 5.6 parts by weight or more in 100 parts by weight of the thermoplastic synthetic resin. It is preferable in obtaining a good adhesive strength. Metallic adhesive polyolefin is thermoplastic synthetic resin 10
If the amount is less than 5.6 parts by weight in 0 parts by weight, the adhesive strength with the magnet structure is inferior, which is not preferable.

As the polymer blend, a combination of a metal-adhesive polyolefin, EVA, and a soft polyolefin can provide sufficient adhesion to the magnet structure and can be molded without using a release agent. It is preferable because the moldability is good, the occlusal pressure is relieved, and the elasticity showing the subsidence amount equivalent to that of the denture base mucosal tissue is obtained.
In this case, as the polymer blend, 5 to 55 parts by weight of the metal adhesive polyolefin, 55 to 25 parts by weight of EVA,
The mixing ratio of 10 to 35 parts by weight of soft polyethylene is appropriate. If the metal adhesive polyolefin is less than 5 parts by weight,
The adhesive strength with the magnet structure is insufficient, which is not preferable.
If it exceeds 55 parts by weight, the adhesive strength to the magnet structure is sufficient, but it is necessary to use a release agent at the time of molding. In this case, the metal-adhesive polyolefin is 5
When the content is not less than 10 parts by weight and has a bonding force with the magnet structure, the releasability is particularly good.
Up to less than 0 parts by weight, there is an adhesive force with the magnet structure, and the releasability and moldability are particularly good. At least 30 parts by weight, the adhesiveness with the magnet structure, mold release, moldability, Elasticity can be balanced. Among them, the most preferable compounding ratio is 30 parts by weight of metal adhesive polyolefin, EV
A 45 parts by weight and 25 parts by weight of soft polyethylene.

For the polymer blend, various methods such as a physical blending method by melting and a reactive processing method can be adopted, but a physical blending method by melting is preferable from the viewpoint of uniform dispersion. In the physical blending by melting, it is preferable to use a single screw extruder or the like when the softening temperature and melt viscosity of the thermoplastic synthetic resin to be blended are close to each other, and the difference in softening temperature is large, and the melt viscosity is also high. If they differ greatly, it is preferable to use a twin screw extruder. The material blended with the polymer and extruded from the extruder is pelletized and subjected to extrusion. According to such a polymer blend, the amount of expensive metal-adhesive polyolefin used can be reduced, and a less expensive dental magnetic attachment having gentle pressure can be provided.

The periodontal ligament is a viscoelastic material, generally
⁷ to 10 ⁸ dyne / cm ² (3.9 × 10 ⁸ dyne / cm ² according to Muhremann's study, 0.23 to 0.43 × 10 ⁸ dyne / cm ^{2 according} to Ast, D., etc.)
It is considered that the thermoplastic synthetic resin has a modulus of elasticity of about ² cm ² ), and if the above-mentioned thermoplastic synthetic resin cannot obtain a subsidence equivalent to that of the mucous membrane, a plasticizer can be added.

As the plasticizer, a phthalate ester, an aliphatic dibasic ester ester, a phosphate ester, an epoxy ester, a fatty ester ester or the like can be used. Examples of phthalate esters include dimethyl phthalate, diethyl phthalate, di-n-butyl phthalate, di-n-octyl phthalate, di-2-ethylhexyl phthalate, diisooctyl phthalate, n-octyl phthalate, and phthalate. For example, n-decyl acid, di-n-decyl phthalate, diisodecyl phthalate, di-n-dodecyl phthalate, diisotridecyl phthalate, dicyclohexyl phthalate, butylbenzyl phthalate, and diethylhexyl isophthalate can be used. Examples of the aliphatic dibasic acid ester include di-2-ethylhexyl adipate, di-n-decyl adipate, diisodecyl adipate, di (methylcyclohexyl) adipate, dibutyl sebacate, and di-2-ethylhexyl sebacate. Can be adopted. Examples of the phosphate ester system include tributyl phosphate, tri-2-ethylhexyl phosphate, 2-ethylhexyl phosphate, 2-diphenyl phosphate, tricresyl phosphate, and the like. As the epoxy type, epoxidized soybean oil, epoxidized tall oil fatty acid 2-ethylhexyl and the like can be used. As fatty acid esters, butyl stearate, butyl oleate, acetylated methyl ricinoleate, and the like can be used. The amount of the plasticizer added to the thermoplastic synthetic resin is desirably 60% or less. If the amount of the plasticizer exceeds 60%, the thermoplastic synthetic resin undergoes plastic deformation, and the shock absorbing ability is deteriorated. In addition, an auxiliary agent, a stabilizer, and the like may be added to the thermoplastic synthetic resin.

In order to produce the dental magnetic attachment having gentle pressure according to the present invention, it is preferable to degrease the magnet structure and clean the surface as a pretreatment step. As the degreasing agent, methyl alcohol, ethyl alcohol, and a nonionic surfactant can be used. In particular, when the surface of the permanent magnet is covered with magnetic stainless steel, ethyl alcohol is desirable. It is not necessary to use a harmful organic solvent such as trichloroethylene which is usually used for cleaning the surface of stainless steel. Therefore,
In manufacturing, the surface of the magnet structure is degreased and cleaned,
Since it is only necessary to provide for molding, the operation is safe and easy, and the production cost does not increase. Also,
The molding temperature, molding time, and molding pressure depend on the molding method and the metal-adhesive polyolefin and / or thermoplastic synthetic resin to be polymer-blended.

[0023]

Embodiments of the present invention will be described below, and the present invention will be described in more detail. Of course, the present invention is not limited by the following embodiments. FIG. 1 shows an example of a dental magnetic attachment (1) having a gentle pressure according to the present invention, which is in a state immediately before a magnet structure (2) is magnetically attracted to a keeper (3). In this example, the dental magnetic attachment (1) is shown as being used for a lower premolar. As shown in FIG. 1, in the dental magnetic attachment (1) having a low pressure according to the present invention, the magnet structure (2) is formed on a surface excluding a joining surface (2a) joined to the keeper (3). And a denture base (6a) provided with a coating layer (4) of a thermoplastic synthetic resin made of at least the metal-adhesive polyolefin described above and covering the gingiva (5) so as to expose the joint surface (2a). It is buried in the denture (6). The keeper (3) is made of a soft magnetic material, and is provided on a root plate (8) embedded in the abutment tooth (7). The denture (6) is installed in the oral cavity by using the magnet structure (2) embedded in the denture (6).
Is bonded to the surface (3a) of the keeper (3), and the magnet structure (2) and the keeper (3) are magnetically attracted.

At the time of mastication, the occlusal pressure due to the mastication force is transmitted to the coating layer (4) of the magnet structure (2) by the engagement with the upper premolar, and the coating layer (4) is applied to the periodontal ligament (9). It can be elastically deformed to compensate for the subsidence amount, and can have the same subsidence amount as the mucosal tissue under the denture base as a whole. Then, the occlusal pressure is buffered by the coating layer (4) provided on the magnet structure (2), and the abutment tooth (7) and the destruction of the mucosal tissue due to the uneven distribution of the load pressure due to the mastication force are prevented. 7) The lever action on the periodontal ligament (9) is reduced and the occlusal balance is maintained, and separation at the interface with the magnet structure (2) does not occur even by long-term mastication, etc. Become.

The magnet structure (2) shown in FIG. 1 has a substantially rectangular joint surface (2a) with the keeper (3), and the surface facing the joint surface (2a) has its periphery rounded off. The coating layer (4) is provided except for the joint surface (2a) with (3), but is not limited to this, and as shown in FIG. 2 (a), except for the joint surface and side surfaces. A coating layer may be provided on a surface facing the bonding surface, and a shape in which the periphery of the surface facing the bonding surface is not angled as shown in FIG. An appropriate shape, such as one provided with a coating layer or one provided with a coating layer on a protruding yoke on the side surface as shown in FIG. 2C, can be adopted.

The thickness of the coating layer made of the thermoplastic synthetic resin is appropriately determined according to the physical properties of the thermoplastic synthetic resin used, the position of the denture in the oral cavity, individual differences in the occlusal pressure of the patient wearing the denture, the occlusal state, and the like. Although it is determined, generally, it is preferably 0.1 to 2.0 mm. When the thickness of the coating layer is less than 0.1 mm, the shock absorbing property of the thermoplastic synthetic resin is insufficient, and the buffering effect of the occlusal pressure due to mastication or the like is small, which may cause damage to the periodontal ligament or a feeling of mastication. Is not preferable because it is not good. Also,
Peeling from the adhesive interface with the magnet structure occurs due to long-term chewing or the like, and the magnet structure may fall off when the denture is attached or detached. Also, when the thickness of the coating layer exceeds 2.0 mm, the shock absorbing property of the thermoplastic synthetic resin is good, but the cushioning effect of the occlusal pressure due to mastication is too large, for example, when masticating a hard material, It is not preferable because chewing feeling such as chewyness is not good.

[0027]

EXAMPLES Next, examples are shown together with comparative examples, and will be described in more detail. (Example 1) As a coating layer, a metal-adhesive polyolefin (trade name; Admer grade XE-
070: Mitsui Petrochemical Industry Co., Ltd.) 30 parts by weight, EV
A (product name; EVAFLEX-1407: manufactured by Mitsui Dupont Chemical Co., Ltd.) 45 parts by weight, soft polyethylene (product name: ULTZEX 20200J: manufactured by Mitsui Petrochemical Industry Co., Ltd.) 25 parts by weight, 230 ° C., 2 hours 30 The mixture was melted and kneaded for 1 minute to obtain a polymer blend. As a magnet structure, a neodymium-iron-boron based rare earth magnet is made of magnetic stainless steel (AUM20; SUS444).
Equivalent: A magnet structure (trade name; Magfit EX600: manufactured by Aichi Steel Co., Ltd.) coated with Aichi Steel Co., Ltd.) was used. After degreased the surface of the magnet structure with ethyl alcohol, it was placed in a mold, and the polymer blend was extruded at a molding temperature of 180 ° C. and a molding time of 10 seconds. Coated with blend. The thickness of the coating layer is 0.5 mm. This molding temperature 1
80 ° C. is a temperature at which the magnetic force of the rare earth magnet is not impaired. Using the obtained magnet structure, partial dentures for three patients having the remaining roots of the lower premolar as abutments were prepared in accordance with a normal denture preparation method. It was worn on three patients each and used clinically for three months. The occlusal conditions were all good, and no damage to the periodontal ligament of the abutment tooth due to leverage was observed. Also, no dropout due to peeling of the magnet structure and the denture was observed.

The adhesiveness of the polymer blend coating layer in the obtained magnet structure was evaluated by peeling the coating layer with pliers and visually observing the state of destruction of the bonding interface. That is, a magnetic stainless steel plate (SUS) made of the same material as that covering the magnet structure described above.
444, size: 25 mm x 175 mm x 2 mm) After degreased the surface with ethyl alcohol, it was placed in a mold, and the above polymer blend was extruded on one side at 180 ° C for a molding time of 10 seconds. Was used as a sample.
The thickness of the polymer blend was 1.2 mm. Five samples were prepared, the coating layer was peeled off with pliers, and it was evaluated which of the three states of the destruction at the interface was cohesive failure, partial cohesive failure, or interfacial delamination of the coating layer. The results are as shown in Table 1.

The mechanism by which the metal-adhesive polyolefin adheres to stainless steel is not clear, but hydrogen bonding between the carboxylic acid introduced by the graft reaction in the metal-adhesive polyolefin and the passive layer on the surface of the stainless steel is not clear. It is considered to have played a major role.

(Example 2) The metal-adhesive polyolefin of Example 1 was used alone as a coating layer. Example 1 A neodymium-iron-boron based rare earth magnet was used as the magnet structure.
A magnet structure (trade name; MAGFIT EX400: manufactured by Aichi Steel Co., Ltd.) coated with the same magnetic stainless steel was used. After the surface of the magnet structure is degreased with ethyl alcohol, it is placed in a mold, and the metal-adhesive polyolefin is extruded at a molding temperature of 180 ° C. and a molding time of 20 seconds, excluding the joining surface of the magnet structure. Coated with a metal adhesive polyolefin. The thickness of the coating layer is 0.5 mm.
Prior to molding, a fluorine-based non-silicon type release agent was applied in the mold. Using the obtained magnet structure,
Partial dentures for three patients using the remaining root of the lower premolar as an abutment were prepared according to a normal denture preparation method. It was worn on three patients each and used clinically for three months. The occlusal conditions were all good, and no damage to the periodontal ligament of the abutment tooth due to leverage was observed. Also, no dropout due to peeling of the magnet structure and the denture was observed. Further, the adhesiveness of the metal-adhesive polyolefin coating layer in the obtained magnet structure was evaluated in the same manner as in Example 1. After the sample was degreased with ethyl alcohol on the surface of the same magnetic stainless steel plate as used in Example 1,
It was placed in a mold, and the one obtained by extruding the metal adhesive polyolefin on one side at 180 ° C. for a molding time of 20 seconds was used. The size of the magnetic stainless steel was the same as in Example 1. The thickness of the metal adhesive polyolefin was 1.2 mm. The results are as shown in Table 1.

(Comparative Example) As a coating layer, 4 parts by weight of the metal-adhesive polyolefin used in Example 1 and EVA
35 parts by weight of soft polyethylene and 35 parts by weight of 230
The mixture was melted and kneaded at a temperature of 2 ° C. for 2 hours and 30 minutes to obtain a polymer blend. The same magnet structure as that used in Example 1 was used, the surface of which was degreased with ethyl alcohol, placed in a mold, and formed at a molding temperature of 185.
The polymer blend was extruded at 10 ° C. for a molding time of 10 seconds, and the magnet structure was covered with the polymer blend except for the joint surface. The thickness of the coating layer is 0.5 mm. Using the obtained magnet structure, partial dentures for three patients having the remaining roots of the lower premolar as abutments were prepared in accordance with a normal denture preparation method. Wear this on three patients each,
Used clinically for 3 months. There was no inconvenience in setting up the occlusal state, and no damage to the periodontal ligament of the abutment teeth due to leverage was observed, but one of the three cases was detached due to peeling of the magnet structure and the denture. Further, the adhesiveness of the polymer blend coating layer in the obtained magnet structure was evaluated in the same manner as in Example 1. A sample was prepared by degreased the surface of the same magnetic stainless steel plate as used in Example 1 with ethyl alcohol, and then placed in a mold and extruded the polymer blend on one surface at 180 ° C. for a molding time of 10 seconds. Was used. The size of the magnetic stainless steel was the same as in Example 1. The thickness of the polymer blend was 1.2 mm. The results are as shown in Table 1.

[0032]

[Table 1]

[0033]

Since the present invention is configured as described above in detail, it has the following effects. The soft magnetic dental attachment of the present invention comprises a keeper provided in the oral cavity and a magnet structure having a permanent magnet magnetically attracted to the keeper, except for a joint surface of the magnet structure with the keeper. A coating layer made of a thermoplastic synthetic resin is provided on at least a surface that receives the occlusal pressure, and since the thermoplastic synthetic resin is made of at least a metal-adhesive polyolefin, sandblasting or primer application to the magnet structure Even if such a treatment is not performed, the metal-adhesive polyolefin exhibits good adhesion to the magnet structure, and the adhesion to the magnet structure is not separated by long-term chewing or the like. And, since the occlusal pressure due to mastication and the like is buffered by the shock absorbing property of the thermoplastic synthetic resin, the use of this magnetic attachment makes the thermoplastic synthetic resin provided in the magnet structure to act as a material for the periodontal ligament with respect to the mastication force. It can be elastically deformed to compensate for the amount of subsidence, and can have the same amount of subsidence as the mucosal tissue under the denture base as a whole. The effect of leverage on the membrane is reduced, the occlusal balance is maintained, the chewing feeling is good, and long-term use is possible. In addition, since a process such as sandblasting or primer application is not required for manufacturing the magnet structure, a dental magnetic attachment having gentle pressure can be supplied at low cost.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a denture using a dental magnetic attachment having gentle pressure according to the present invention.

FIG. 2 is a cross-sectional view showing another example of the magnet structure of the dental magnetic attachment having gentle pressure according to the present invention.

FIG. 3 is an explanatory view of a denture using a conventional magnetic attachment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic attachment 2 Magnet structure 3 Keeper 4 Coating layer 6 Denture 7 Abutment tooth 8 Base plate

Claims (4)

[Claims] 1. A dental magnetic attachment comprising a keeper provided in an oral cavity and a magnet structure having a permanent magnet magnetically attracted to the keeper, wherein the magnet structure excludes a joint surface with the keeper. A coating layer made of a thermoplastic synthetic resin is provided on at least a surface that receives an occlusal pressure, and the thermoplastic synthetic resin is made of at least a metal-adhesive polyolefin. Magnetic attachment. 2. The soft magnetic dental attachment according to claim 1, wherein the metal-adhesive polyolefin is obtained by introducing a carboxylic acid into a very low-density polyethylene by a graft reaction. 3. The dental magnetic attachment having gentle pressure according to claim 1, wherein the metal-adhesive polyolefin is 5.6 parts by weight or more based on 100 parts by weight of the thermoplastic synthetic resin. 4. The thermoplastic synthetic resin comprises a polymer blend of 5 to 55 parts by weight of a metal-adhesive polyolefin, 55 to 25 parts by weight of EVA, and 10 to 35 parts by weight of soft polyethylene. 3. A dental magnetic attachment having gentle pressure according to 1 or 2.