JP3555915B2

JP3555915B2 - Denture attachment

Info

Publication number: JP3555915B2
Application number: JP29077596A
Authority: JP
Inventors: 義信本蔵; 一生荒井; 亜起度会; 蕾田; 一誠木村
Original assignee: Aichi Steel Corp
Current assignee: Aichi Steel Corp
Priority date: 1996-10-31
Filing date: 1996-10-31
Publication date: 2004-08-18
Anticipated expiration: 2016-10-31
Also published as: JPH10127662A

Description

【０００１】
【発明の属する技術分野】
本発明は、磁気吸引力によって義歯を歯根部に着脱自在に固定する義歯アタッチメントに関する。
【０００２】
【従来の技術】
従来より、抜歯患者の歯根部に植込み処置された軟磁性材料製の吸着板に磁気吸引力によって人工歯を着脱自在に固定する義歯アタッチメントが提供されている（特開平１−３０３１４５，米国特許５，０１３，２４３号公報等）。
上記磁気吸引式の義歯アタッチメントは、図７に示すように、歯根部の表層部形状に合致させた義歯床１に人工歯２が一体化された義歯エレメントに添設される磁石構造体３にて構成され、該磁石構造体３は被着板５と対向する下面が義歯床１より露出するように、図７では義歯床１と面一となるように人工歯２と義歯床１との間に設けられる。磁石構造体３は図８に示すように、偏平柱状の永久磁石３ａを耐食性のあるヨーク部３ｂで囲包したもので、永久磁石３ａは例えばＳｍ（サマリウム）−Ｃｏ（コバルト）系の希土類磁石が、ヨーク部３ｂは耐食性軟磁性合金が用いられる。そしてヨーク部３ｂには、磁気抵抗として非磁性リング７が被着板５に対面する下面に設けられる。
【０００３】
上記図８に示す磁石構造体３を用いた義歯アタッチメントは、図８に示すように、磁石構造体３と被着板５とで形成される磁気回路φがドーナツ状に形成され、ヨーク部３ａの下面側と被着板５との間に吸着力が発生して義歯を歯根部に固定するものである。
【０００４】
【発明が解決しようとする課題】
ところで、義歯の固定強度は、磁石構造体３に使用する永久磁石量によって決定される。従って、磁石構造体３の面積条件を一定とすると、磁石構造体３の厚み（磁石構造体３の歯丈方向の寸法）を大きくすればするほど永久磁石の厚みをもたせて固定強度を増すことができる。
【０００５】
しかしながら、特に図７に示す人口歯２のような奥歯では、対向歯が嵌合する中央が凹んだ噛合溝部４を有しており、磁石構造体を人工歯に組込むための歯丈方向のスペースが制限される。従って、図８のような磁石構造体３の場合、噛合溝部４の高さＨを低くできる薄くて固定強度が十分に大きな磁石構造体が要求される。
【０００６】
本発明は、上記従来技術の問題を考慮してなされたものであり、磁石体をヨークで囲包して構成する磁石構造体において、扁平柱状の永久磁石を用いる場合より薄くて十分な固定強度を得る技術的手段を提供することを解決すべき課題とする。
【０００７】
【課題を解決するための手段】
上記課題を解決すべく本発明の請求項１で採用した技術的手段は、義歯に埋込む磁石構造体の磁石体を、歯丈方向と交差したほぼリング状に形成し、該磁石体の外周部側面及び上面を覆い、その中央孔を埋めて連続して一体的に形成されているヨーク部を設けたことにより、該磁石体によりヨーク部と被着板とで形成される磁気回路は、歯丈方向に磁化された該磁石体から出た磁束が該ヨーク部の上面のヨークを通り、側面のヨーク、該被着板を経由して該磁石体に戻る該磁石体の外側に形成される磁気回路と、該磁石体から出た磁束が該ヨーク部の上面のヨークを通り、中央孔のヨーク、該被着板を経由して該磁石体に戻る該磁石体の内側に形成される磁気回路との２つのルートとなる。
従って、該磁石体の外側と内側にドーナツ状の磁気回路が二重に形成されることとなる。このため、一重しかできない偏平柱状の磁石体に較べ、リング状の磁石体ではヨーク部と被着板とで実質的に吸着に関与する面積が増える。これにより、外径を同じにした偏平柱状磁石体とリング状磁石体とでそれぞれ磁石構造体を構成した場合、リング状磁石体による磁石構造体は薄くても固定強度が強くなり、奥歯のような歯丈方向にスペースの少ない義歯に容易に埋め込むことができる。
なお、該磁石体の磁化の方向が上記のものと逆のときは、該磁石体の外側には、該磁石体から出た磁束が該被着板、該ヨーク部の側面のヨーク、上面のヨークの経路を順にたどり該磁石体に戻る磁気回路が形成され、また、該磁石体の内側には、該磁石体から出た磁束が該被着板、該ヨーク部の中央孔のヨーク、上面のヨークの経路をたどり該磁石体に戻る磁気回路が形成されることとなるが該磁石構造体と該被着板との吸着力は上記のときと同じである。
また、請求項２の発明は、請求項１に記載された義歯アタッチメントにおいて、磁石構造体には、該磁石体の下面側に当接するリング状の蓋ヨークと、該磁石体の下面側の外周部および内周部に接する該ヨーク部の間隙に形成された非磁性リングとが配設されているため、磁束の通過をより効率的にし、磁石体の外側及び内側に形成される磁気回路の短絡防止に効果がある。
【０００８】
また、人口歯の高さへの影響も少なくなるので、個人差の大きい噛合い高さの調整も容易になる。
【０００９】
【発明の実施の形態】
本発明の義歯アタッチメントの好適な実施形態は、人工歯の底面側に添設される磁石構造体が、歯丈方向と交差するリング状の磁石体と、磁石体の外周部側面及び上面を覆い、その中央孔を埋めて連続して一体的に形成されていて磁石体及び被着板との間で磁気回路を形成する耐食軟磁性体製のヨーク部とを有する。
【００１０】
磁石体は、Ｎｄ（ネオジム）−Ｆｅ−Ｂ（ホウ素）系の希土類磁石、Ｓｍ−Ｃｏ系希土類磁石を用いる。Ｎｄ−Ｆｅ−Ｂ系では４０ＭＧＯｅ以上、Ｓｍ−Ｃｏ系では３０ＭＧＯｅ以上のエネルギ積とする。
ヨーク部は、被冠ヨークと、蓋ヨークとから構成する。被冠ヨークは、リング状の収容溝を有した断面Ｍ字状に形成し磁石体の一方の磁極面（義歯床側に向く面）を露出して該収容溝に該磁石体を嵌合できる。蓋ヨークは、上記磁極面をシールして磁石体を隠蔽する。被冠ヨーク及び蓋ヨークはＣｒ単体材でもよいが、好ましくはＣｒ−Ｍｏ−Ｔｉ系合金を用いる。なお、被冠ヨークと蓋ヨークとの外側と内側の接合部分には非磁性リングを介装したり、被冠ヨークと蓋ヨーク、いずれかのヨーク材をレーザ等により改質して形成することができる。
【００１１】
【実施例】
以下、本発明を図面を参照して具体的に説明する。
本発明に係る義歯アタッチメントを用いた義歯１１は、基本的に図１に示すように、末広がり状の義歯床１２と、該義歯床１２に１個〜複数個配設された人工歯１３と、義歯床１２のアタッチメント取付け溝に位置決め固着されるとともに、人工歯１３の底面側に接着、圧入等の固着手段により添設された磁石構造体１４とから構成され、歯根部内に予め処置された軟磁性合金からなる被着板１５が磁石構造体１４に磁気吸引力によって吸着することにより歯根部に着脱自在に固定される。
【００１２】
上記義歯１１に用いた第１実施例の上記磁石構造体１４は、図２に拡大して示すように、歯丈方向Ａと交差するリング状で同歯丈方向Ａに磁化方向をもつ永久磁石による磁石体１６と、該磁石体１６の外周部側面及び上面を覆い、その中央孔を埋めて連続して一体的に形成されているヨーク部１７とから構成される。ヨーク部１７は、図３に示すように、磁石体１６に対応したリング状の収容溝１８ａを有した断面がほぼＭ字状の被冠ヨーク１８と、上記収容溝１８ａの開口側を覆い磁石体１６を収容溝１８ａ内にシールするリング状の蓋ヨーク１９とから構成される。被冠ヨーク１８と蓋ヨーク１９との外側及び内側の間隙には磁気抵抗としての非磁性リング２０，２１が配設される。
【００１３】
ここで、磁石体１６の永久磁石としては、エネルギ積が３０〜４０ＭＧＯｅ以上の希土類磁石、例えばＳｍ−Ｃｏ系合金、Ｎｄ−Ｆｅ−Ｂ系合金が実用的である。また、ヨーク部１７の軟磁性材としては、耐食性のあるステンレス鋼が好ましい。これにより、磁石体１６の腐食を防止する。
このような構成の義歯アタッチメントでは、人工歯１３の底面側に添設された磁石構造体１４は、被着板１５に吸着してヨーク部１７と被着板１５との間に磁気回路を形成する。この磁気回路は、ヨーク部１７によって囲包される磁石体１６がリング状であり、符号２２，２３にて示すように二重ドーナツ状に形成される。このように磁気回路が二重に形成されると、被着板１５に流れる磁束の断面積が広くなり、ヨーク部１７と被着板１５とが実質的に吸着する面積が、図８に示すヨーク部３ｂと被着板５との吸着面より広くなる。従って、リング状の磁石体１６を囲包したヨーク部１７は、扁平柱状の磁石体３ａを囲包したヨーク部３ｂより固定強度が強くできる。これによれば、磁石体１６の厚みをリング状でない単に偏平柱状のものより薄くしても、十分な固定強度が確保できる。このため、義歯アタッチメント１４全体の厚み（高さ）を薄くでき、奥歯のような歯丈方向にスペースの少ない人工歯にも容易に組込むことができる。
【００１４】
また、副次的効果として、磁石構造体１４を薄くできる分、義歯の高さを低く抑えることができ、個人差に応じた噛合溝部１３ａの高さＨを加減する範囲が広がり、噛合い高さ調整がより自由に行うことが可能となる。
上記第１実施例に基づいて構成した具体的な義歯アタッチメントの各部品の諸元の一例を表１に示す。表２に比較例として図８のような扁平柱状の磁石体を用いて製作した義歯アタッチメントの諸元を示す。
【００１５】

表１と表２を比較してわかるように、ほぼ同じエネルギ積の固定強度を得るのに、本発明の義歯アタッチメントは、磁石体１６の高さｈ１を従来の磁石体３ａの高さｈａの半分にできた。
【００１６】
上記高さの磁石１６で実際に磁石構造体を製作すると、表３に示すような大きさの磁石構造体１４を製作することができる。

表３のように磁石構造体１４の高さは、１．０ｍｍにでき、扁平柱状の磁石体３ａを用いる場合の被冠ヨーク３ｂの高さが１．５ｍｍであることから、ほぼ同じ固定強度の義歯アタッチメントを３分の２の薄さに製作することが可能となる。
【００１７】
なお、上記義歯アタッチメント１４は、被冠ヨーク１８，磁石体１６，蓋ヨーク１９及び非磁性リング２０，２１の各部品を用意し、被冠ヨーク１８の下面側に形成した凹欠１８ａに磁石体１６を嵌合した後、蓋ヨーク１９及び非磁性リング２０，２１の順に接着等の固着手段によって図３のように組付ける。
別の方法として、非磁性リング２０，２１は磁性材料をレーザ等による改質手段によって改質できるので、蓋ヨーク１９で磁石体１６を覆った後に外側及び内側の間隙位置にレーザ等を照射することにより形成してもよい。
【００１８】
次に本発明の第２実施例を図４及び図５によって説明する。図４に示す磁気アタッチメント３２（磁石構造体）は、歯丈方向Ａと交差するリング状の磁石体３３と、該磁石体３３の中央孔を埋めるように該磁石体３３を囲包した耐食軟磁性体製のヨーク部３４とからなるとともに、ヨーク部３４は人工歯１３の底面側に向く磁石体１６の磁極面側を被冠した被冠ヨーク３５と、義歯床面となる磁極面側を覆う蓋ヨーク３６とからなり、かつ被冠ヨーク３５と蓋ヨーク３６との外側及び内側の間隙に非磁性リング３８，３７が配設される構成は第１実施例と同じであるが、被冠ヨーク３５には、人工歯の底面側に対向する上面に凹部３９が形成される構成が第１実施例と異なる。
【００１９】
上記義歯アタッチメント３２も第１実施例と同様の組付け手順や、レーザ光による改質手段によって製作することができる。
上記のような構成の義歯アタッチメント３２によっても磁石体３３がリング状であり、磁石体３３と被着板１５とで形成される磁気回路は、符号３９，４０にて示すように二重ドーナツ状に形成され、被着板１５に流れる磁束の面積を広くできて固定強度を強くすることができる。
【００２０】
また、第１実施例に較べ、ヨーク部３４に凹部３９を形成することにより、図１における噛合凹部１３ａの高さＨをより低くできる。このことは噛合い高さ調整自由度を一層広げることが可能となる。
上記第２実施例に基づいて構成した具体的な義歯アタッチメントの各部品の諸元の一例を表４に示す。
【００２１】

上表４で被冠ヨークの外内径とは、凹部３９の外径をいう。
【００２２】
このような義歯アタッチメントは、次表５に示すように、噛合凹部１３ａの高さＨ（最小高さ）を０．５ｍにできる。従来の磁石構造体では最大高さも最小高さも１ｍｍであり、磁石体３３がリング状であることにより、凹部３９を設けることができ、これによりいかに最小高さを小さくできるかがわかる。

また、第２実施例の変形態様として、図６に示すように、リング状磁石体３３の中央孔を貫通する貫通孔４１を設けても、二重ドーナツ状の磁気回路３９，４０が形成され、各実施例と固定強度がほぼ同じで、従来より薄い義歯アタッチメントを製作することができる。この変形例では、貫通孔４１により凹部を１３９を設ける第２実施例より更に噛合凹部１３ａの高さを小さくできることである。
【００２３】
この変形例の具体的構成例を表６に示す。この具体例では、磁石体３３としてＳｍ−Ｃｏ系合金を用いているので、ＮｄＦｅＢより固定強度は若干落ちるが、実用的には問題はない。

【００２４】
【発明の効果】
以上述べたように本発明の義歯アタッチメントは、磁石体をリング状とし、磁石体の外周部側面及び上面を覆い、その中央孔を埋めて連続して一体的に形成されているヨーク部を設けたので、磁石体及び被着板との間でドーナツ状の磁気回路が二重に形成されることとなり、扁平柱状の磁石体の場合より薄くても十分な固定強度が得られ、特に奥歯のように歯丈方向のスペースのない義歯でも容易に磁石構造体を組込むことができる。
また、磁石構造体を薄くできるので、人工歯の部分での噛合い高さ調整範囲を広げることができる利点もある。
【図面の簡単な説明】
【図１】本発明の第１実施例に係る義歯アタッチメントを採用した義歯を示す断面図である。
【図２】本発明の第１実施例に係る義歯アタッチメントを示す断面図である。
【図３】上記第１実施例の構成要素を分解して示す組付け構成図である。
【図４】本発明の第２実施例に係る義歯アタッチメントを示す断面図である。
【図５】上記第２実施例の構成要素を分解して示す組付け構成図である。
【図６】上記第２実施例の変形態様を示す断面図である。
【図７】従来の義歯アタッチメントを用いた義歯を示す断面図である。
【図８】従来の義歯アタッチメントを示す断面図である。
【符号の説明】
１１は義歯、１２は義歯床、１３は人工歯、１３ａは噛合溝部、１４は磁石構造体（義歯アタッチメント）、１５は被着板、２１，３９，４１は凹部、１６，３３は磁石体、１７，３４はヨーク部、１９は蓋ヨーク、２２，３９，４０は磁気回路、２０，３７，３８は非磁性リングであり、図１〜図３で共通の要素には同一の符号を付し、図４〜図６で共通の要素には同一の符号を付す。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a denture attachment for detachably fixing a denture to a root portion by magnetic attraction.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been provided a denture attachment in which an artificial tooth is detachably fixed to a suction plate made of a soft magnetic material implanted in a tooth root portion of an extraction patient by magnetic attraction (Japanese Patent Application Laid-Open No. 1-3303145, US Pat. , 013,243, etc.).
As shown in FIG. 7, the magnetic attraction type denture attachment includes a magnet structure 3 attached to a denture element in which an artificial tooth 2 is integrated with a denture base 1 conforming to the surface layer shape of a tooth root. The artificial tooth 2 and the denture base 1 are configured so that the lower surface of the magnet structure 3 facing the adherend plate 5 is exposed from the denture base 1 and is flush with the denture base 1 in FIG. It is provided between them. As shown in FIG. 8, the magnet structure 3 includes a flat columnar permanent magnet 3a surrounded by a corrosion-resistant yoke portion 3b. The permanent magnet 3a is, for example, an Sm (samarium) -Co (cobalt) -based rare earth magnet. However, the yoke portion 3b is made of a corrosion-resistant soft magnetic alloy. In the yoke 3b, a non-magnetic ring 7 is provided as a magnetic resistance on the lower surface facing the adherend plate 5.
[0003]
As shown in FIG. 8, in the denture attachment using the magnet structure 3 shown in FIG. 8, the magnetic circuit φ formed by the magnet structure 3 and the adherend plate 5 is formed in a donut shape, and the yoke 3a Attachment force is generated between the lower surface of the base plate and the adherend plate 5 to fix the denture to the root portion.
[0004]
[Problems to be solved by the invention]
By the way, the fixing strength of the denture is determined by the amount of the permanent magnet used for the magnet structure 3. Therefore, assuming that the area condition of the magnet structure 3 is constant, the larger the thickness of the magnet structure 3 (the dimension in the tooth height direction of the magnet structure 3), the greater the permanent magnet thickness and the higher the fixing strength. Can be.
[0005]
However, in particular, the back tooth such as the artificial tooth 2 shown in FIG. 7 has the meshing groove portion 4 in which the center is fitted with the opposed tooth, and the space in the length direction for incorporating the magnet structure into the artificial tooth. Is limited. Therefore, in the case of the magnet structure 3 as shown in FIG. 8, a thin and sufficiently large fixing strength that can reduce the height H of the engagement groove portion 4 is required.
[0006]
The present invention has been made in consideration of the above-described problems of the related art, and has a magnet structure formed by surrounding a magnet body with a yoke, which is thinner and has a sufficient fixing strength as compared with a case where a flat columnar permanent magnet is used. The problem to be solved is to provide technical means for obtaining
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, a technical means adopted in claim 1 of the present invention is to form a magnet body of a magnet structure to be embedded in a denture into a substantially ring shape crossing a tooth length direction, and to form an outer periphery of the magnet body. The magnetic circuit formed by the magnet body and the attached plate by covering the side surface and the upper surface, and by providing the yoke portion continuously and integrally formed by filling the center hole thereof , Magnetic flux emitted from the magnet body magnetized in the tooth length direction is formed outside the magnet body returning to the magnet body through the yoke on the upper surface of the yoke portion, the yoke on the side surface, and the attaching plate. And a magnetic flux generated from the magnet body is formed inside the magnet body passing through the yoke on the upper surface of the yoke portion, returning to the magnet body via the yoke in the center hole, and the attaching plate. There are two routes to the magnetic circuit .
Accordingly, a donut-shaped magnetic circuit is formed doubly on the outside and inside of the magnet body . For this reason, in the ring-shaped magnet body, the area which substantially participates in the attraction between the yoke portion and the adherend plate is increased as compared with the flat columnar magnet body which can be formed only once. Thereby, when the magnet structure is composed of the flat columnar magnet body and the ring-shaped magnet body having the same outer diameter, respectively, the fixing strength becomes strong even if the magnet structure by the ring-shaped magnet body is thin, such as the back teeth. It can be easily embedded in a denture with a small space in the vertical direction.
When the direction of magnetization of the magnet body is opposite to that described above, the magnetic flux coming out of the magnet body is applied to the outside of the magnet body, the attached plate, the yoke on the side surface of the yoke portion, and the upper surface. A magnetic circuit is formed which follows the path of the yoke in order and returns to the magnet body. Inside the magnet body, a magnetic flux emitted from the magnet body is formed by the attachment plate, the yoke of the center hole of the yoke part, and the upper surface. A magnetic circuit that follows the path of the yoke and returns to the magnet body is formed, but the attraction force between the magnet structure and the adherend plate is the same as above.
According to a second aspect of the present invention, in the denture attachment according to the first aspect, the magnet structure includes a ring-shaped lid yoke that abuts on a lower surface side of the magnet body and an outer periphery on a lower surface side of the magnet body. And the non-magnetic ring formed in the gap between the yoke portion contacting the inner portion and the inner peripheral portion, so that the passage of magnetic flux is made more efficient, and the magnetic circuit formed outside and inside the magnet body is Effective for short circuit prevention.
[0008]
In addition, since the influence on the height of the artificial tooth is reduced, it is easy to adjust the meshing height, which has a large individual difference.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
In a preferred embodiment of the artificial tooth attachment according to the present invention, the magnet structure attached to the bottom surface side of the artificial tooth covers a ring-shaped magnet body intersecting the tooth length direction, and an outer peripheral side surface and an upper surface of the magnet body. And a yoke made of a corrosion-resistant soft magnetic material that is formed continuously and integrally with the center hole so as to form a magnetic circuit between the magnet body and the adherend plate.
[0010]
As the magnet body, an Nd (neodymium) -Fe-B (boron) -based rare earth magnet or an Sm-Co-based rare earth magnet is used. The energy product is 40 MGOe or more for the Nd-Fe-B system and 30 MGOe or more for the Sm-Co system.
The yoke portion includes a crown yoke and a lid yoke. The crowned yoke is formed in an M-shaped cross section having a ring-shaped accommodation groove, and one of the magnetic pole faces (the surface facing the denture base side) of the magnet body is exposed, so that the magnet body can be fitted into the accommodation groove. . The lid yoke seals the magnetic pole surface to hide the magnet body. Although the crown yoke and the cover yoke may be made of Cr alone, a Cr-Mo-Ti alloy is preferably used. A non-magnetic ring may be interposed between the outer and inner joints between the crown yoke and the cover yoke, or the cover yoke and the cover yoke may be formed by modifying one of the yoke materials using a laser or the like. Can be.
[0011]
【Example】
Hereinafter, the present invention will be specifically described with reference to the drawings.
The denture 11 using the denture attachment according to the present invention basically includes, as shown in FIG. 1, a denture base 12 having a divergent shape, and an artificial tooth 13 provided in one to a plurality of denture bases 12. A magnet structure 14 which is positioned and fixed in the attachment mounting groove of the denture base 12 and is attached to the bottom surface side of the artificial tooth 13 by a fixing means such as bonding or press-fitting. The attachment plate 15 made of a magnetic alloy is detachably fixed to the root by adsorbing to the magnet structure 14 by magnetic attraction.
[0012]
The magnet structure 14 of the first embodiment used for the denture 11 is a permanent magnet having a ring shape crossing the tooth height direction A and having a magnetization direction in the tooth height direction A as shown in an enlarged view in FIG. And a yoke portion 17 which covers the outer peripheral side surface and the upper surface of the magnetic body 16 and fills up a central hole thereof and is formed continuously and integrally . As shown in FIG. 3, the yoke portion 17 has a substantially Y-shaped crowned yoke 18 having a ring-shaped accommodation groove 18a corresponding to the magnet body 16, and a magnet covering the opening side of the accommodation groove 18a. A ring-shaped lid yoke 19 for sealing the body 16 in the accommodation groove 18a.

Non-magnetic rings

20 and 21 serving as magnetic resistance are disposed in the outer and inner gaps between the crowned yoke 18 and the lid yoke 19.
[0013]
Here, as the permanent magnet of the magnet body 16, a rare earth magnet having an energy product of 30 to 40 MGOe or more, for example, an Sm-Co alloy or an Nd-Fe-B alloy is practical. The soft magnetic material of the yoke 17 is preferably stainless steel having corrosion resistance. Thereby, corrosion of the magnet body 16 is prevented.
In the artificial tooth attachment having such a configuration, the magnet structure 14 attached to the bottom surface side of the artificial tooth 13 is attracted to the attachment plate 15 to form a magnetic circuit between the yoke portion 17 and the attachment plate 15. I do. In this magnetic circuit, the magnet body 16 surrounded by the yoke portion 17 has a ring shape, and is formed in a double donut shape as indicated by

reference numerals

22 and 23. When the magnetic circuit is formed double in this manner, the cross-sectional area of the magnetic flux flowing through the adherend plate 15 increases, and the area where the yoke portion 17 and the adherend plate 15 are substantially attracted is shown in FIG. It is wider than the suction surface between the yoke portion 3b and the adherend plate 5. Therefore, the yoke portion 17 surrounding the ring-shaped magnet body 16 can have higher fixing strength than the yoke portion 3b surrounding the flat columnar magnet body 3a. According to this, sufficient fixing strength can be ensured even if the thickness of the magnet body 16 is made thinner than that of a simple flat pillar that is not ring-shaped. For this reason, the thickness (height) of the entire denture attachment 14 can be reduced, and it can be easily incorporated into an artificial tooth having a small space in the length direction such as a back tooth.
[0014]
In addition, as a secondary effect, the height of the denture can be suppressed to a low level because the magnet structure 14 can be made thinner, and the range of adjusting the height H of the meshing groove portion 13a according to individual differences is widened. The adjustment can be performed more freely.
Table 1 shows an example of the specifications of each component of a specific denture attachment configured based on the first embodiment. Table 2 shows specifications of a denture attachment manufactured using a flat columnar magnet body as shown in FIG. 8 as a comparative example.
[0015]

As can be seen by comparing Tables 1 and 2, in order to obtain almost the same fixed strength of the energy product, the denture attachment of the present invention requires the height h1 of the magnet body 16 to be equal to the height ha of the conventional magnet body 3a. Made in half.
[0016]
When a magnet structure is actually manufactured with the magnet 16 having the above height, a magnet structure 14 having a size as shown in Table 3 can be manufactured.

As shown in Table 3, the height of the magnet structure 14 can be set to 1.0 mm, and the height of the crowned yoke 3b is 1.5 mm when the flat columnar magnet body 3a is used. Can be manufactured to be two-thirds thinner.
[0017]
The above-described denture attachment 14 is prepared by preparing components such as a crowned yoke 18, a magnet body 16, a lid yoke 19, and

non-magnetic rings

20 and 21, and a magnet body is formed in a recess 18a formed on the lower surface side of the crowned yoke 18. After fitting, the cover yoke 19 and the

non-magnetic rings

20 and 21 are assembled in this order by fixing means such as adhesion as shown in FIG.
As another method, since the

non-magnetic rings

20 and 21 can modify the magnetic material by a reforming means using a laser or the like, the outer yoke 19 covers the magnet body 16 and then irradiates the outer and inner gap positions with the laser or the like. Alternatively, it may be formed.
[0018]
Next, a second embodiment of the present invention will be described with reference to FIGS. A magnetic attachment 32 (magnet structure) shown in FIG. 4 includes a ring-shaped magnet 33 intersecting with the tooth height direction A, and a corrosion-resistant soft material surrounding the magnet 33 so as to fill a central hole of the magnet 33. The yoke portion 34 is made of a magnetic material. The yoke portion 34 is formed of a crowned yoke 35 covering the magnetic pole surface side of the magnet body 16 facing the bottom surface side of the artificial tooth 13 and a magnetic pole surface side serving as a denture base surface. The structure of the cover yoke 36 and the

non-magnetic rings

38 and 37 disposed in the outer and inner gaps between the crown yoke 35 and the cover yoke 36 is the same as that of the first embodiment. The configuration of the yoke 35 is different from that of the first embodiment in that a concave portion 39 is formed on the upper surface facing the bottom side of the artificial tooth.
[0019]
The denture attachment 32 can also be manufactured by the same assembling procedure as in the first embodiment, or by a modifying means using laser light.
Even with the denture attachment 32 having the above-described configuration, the magnet body 33 has a ring shape, and the magnetic circuit formed by the magnet body 33 and the attachment plate 15 has a double donut shape as indicated by

reference numerals

39 and 40. Thus, the area of the magnetic flux flowing through the adherend plate 15 can be increased, and the fixing strength can be increased.
[0020]
In addition, by forming the concave portion 39 in the yoke portion 34, the height H of the meshing concave portion 13a in FIG. 1 can be made lower than in the first embodiment. This makes it possible to further increase the degree of freedom in adjusting the engagement height.
Table 4 shows an example of the specifications of each component of a specific denture attachment configured based on the second embodiment.
[0021]

In Table 4 above, the outer diameter of the crowned yoke refers to the outer diameter of the recess 39.
[0022]
With such a denture attachment, as shown in Table 5 below, the height H (minimum height) of the meshing concave portion 13a can be set to 0.5 m. In the conventional magnet structure, both the maximum height and the minimum height are 1 mm, and since the magnet body 33 has a ring shape, the concave portion 39 can be provided, and it can be seen how the minimum height can be reduced by this.

As a modification of the second embodiment, as shown in FIG. 6, even if a through hole 41 penetrating through the center hole of the ring-shaped magnet body 33 is provided, the double donut-shaped

magnetic circuits

39 and 40 are formed. The fixing strength is almost the same as that of each embodiment, and a thinner denture attachment than the conventional one can be manufactured. In this modification, the height of the meshing concave portion 13a can be further reduced as compared with the second embodiment in which the concave portion 139 is provided by the through hole 41.
[0023]
Table 6 shows a specific configuration example of this modified example. In this specific example, since the Sm-Co alloy is used for the magnet 33, the fixing strength is slightly lower than that of NdFeB, but there is no practical problem.

[0024]
【The invention's effect】
As described above, the denture attachment of the present invention provides a yoke portion which is formed in a ring shape of the magnet body, covers the outer peripheral side surface and the upper surface of the magnet body, fills the central hole thereof, and is continuously and integrally formed. Therefore, a donut-shaped magnetic circuit is formed doubly between the magnet body and the adherend plate, and a sufficient fixing strength can be obtained even if the magnet body is thinner than a flat columnar magnet body, As described above, the magnet structure can be easily incorporated even in a denture having no space in the tooth height direction.
Further, since the magnet structure can be made thin, there is an advantage that the range of adjusting the meshing height at the artificial tooth can be widened.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a denture employing a denture attachment according to a first embodiment of the present invention.
FIG. 2 is a sectional view showing a denture attachment according to the first embodiment of the present invention.
FIG. 3 is an assembly configuration diagram showing components of the first embodiment in an exploded manner.
FIG. 4 is a sectional view showing a denture attachment according to a second embodiment of the present invention.
FIG. 5 is an exploded view showing components of the second embodiment.
FIG. 6 is a sectional view showing a modification of the second embodiment.
FIG. 7 is a sectional view showing a denture using a conventional denture attachment.
FIG. 8 is a cross-sectional view showing a conventional denture attachment.
[Explanation of symbols]
11 is a denture, 12 is a denture base, 13 is an artificial tooth, 13a is a meshing groove portion, 14 is a magnet structure (denture attachment), 15 is an attachment plate, 21, 39, 41 are concave portions, and 16 and 33 are magnet bodies. 17 and 34 are yoke parts, 19 is a cover yoke, 22, 39 and 40 are magnetic circuits, 20, 37 and 38 are non-magnetic rings, and common elements in FIGS. 4 to FIG. 6 are denoted by the same reference numerals.

Claims

A denture having an artificial tooth, comprising a magnet structure attached to the bottom surface side of an artificial tooth, which is attracted by magnetic attraction to an adhered plate made of a soft magnetic material implanted in a tooth root and treated. A denture attachment that is removably fixed to the root portion,
The magnet structure is formed integrally with the magnet body, which forms a substantially ring-like shape crossing the tooth length direction, and covers the outer peripheral side surface and the upper surface of the magnet body and fills the center hole thereof to be continuous. It is composed of a yoke part,
A magnetic flux, which is magnetized in the tooth length direction and is emitted from the magnet body between the magnet body and the attachment plate , passes through the upper surface portion, the outer peripheral side surface portion, and the attachment plate of the yoke portion, and A magnetic circuit formed outside the magnet body returning to the body, and the magnet returning a magnetic flux from the magnet body to the magnet body via the upper surface portion, the center hole portion, and the adherend of the yoke portion A denture attachment, characterized in that a magnetic circuit of two routes with a magnetic circuit formed inside the body is formed in duplicate .

The magnet structure, a ring-shaped lid yoke abutting on the lower surface side of the magnet body,
The denture attachment according to claim 1, further comprising a non-magnetic ring formed in a gap between the yoke portion and the outer and inner peripheral portions on the lower surface side of the magnet body.