JP2555077C - - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a composite implant for living organisms, and more particularly to a dental implant to be implanted in alveolar bone for mounting an artificial crown. (Prior Art) Some typical dental implants have already been put into practical use as composite implants. For example, there is a material made of Alnami or titanium which is inactive against a living body, and processed into various forms, such as a screwing method, which can be implanted in a jaw bone. There is also a type in which calcium hydroxyapatite ceramics having a high biocompatibility is used as a material and the plant is measured by direct attachment to bone. However, all of these dental implants have the following problems. That is, the former is held in the jawbone only by mechanical force and easily falls off when used for a long time. Also, the latter dental implant has the property of adhering to bone as described above,
After implantation, the abutment protrudes into the oral cavity, so that it is difficult to maintain a resting state, which causes swaying, inhibits adhesion to bone, and easily falls off like the above-mentioned dental implant. In contrast, implantable dental implants have been proposed as an improvement of the above dental implants [John R. Smith, American Journal of Orthodontics (Am. J. Orthod.) 76 , 618 (1979)
And JP-A-56-13654]. The dental implant is made of a hollow metal or ceramic coated with calcium phosphate or bioactive glass such as calcium hydroxyapatite having a high biocompatibility, and as an operation method,
In the first operation, the dental implant is implanted under the mucous membrane in the jaw bone, and after the implant and the bone are completely attached, the abutment is attached in the second operation. A method has been reported in which calcium phosphate or bioactive glass and metal are bonded to the dental implant with glass by dipping, baking, or the like (Japanese Patent Application Laid-Open No. 58-1983).
118746, Japanese Dental Review, No. 512, 187-197 (1985)),
When the dental implant bonded with glass in this way is used for a long time, the glass of the adhesive layer is eluted, and the calcium phosphate or bioactive glass and the metal are separated. As another method for coalescence of calcium phosphate and metal in a dental implant, thermal spraying by plasma or the like (JP-A-53-28997, JP-A-62-3455)
8) and bonding with an epoxy resin (Japanese Patent Publication No. 62-3121). However, in the former case, the calcium phosphate and the metal are separated when used for a long period of time, as in the case of the above-mentioned bonding with glass. In the latter case, especially, the adhesive strength of the epoxy resin to calcium phosphate and metal in the living body is small, and it is difficult to use it as a dental implant. In addition, the toxicity of the epoxy resin in vivo is also a problem. (Problems to be Solved by the Invention) Accordingly, a problem to be solved by the present invention is to obtain a composite implant in which an outer layer made of calcium phosphate and an inner metal substrate are firmly fixed. (Means for Solving the Problems) As a result of intensive studies to solve the problems, the present inventors have reached the present invention described below. That is, the present invention relates to a composite implant in which an outer layer made of calcium phosphate and a metal substrate in the outer layer are fixed by a polymer having a (meth) acrylic monomer unit having an acidic group as a constituent unit. Such implants are useful as implantable dental implants. FIG. 1 shows an example of an implantable dental implant according to the present invention. Reference numeral 1 denotes an outer layer made of calcium phosphate, which is a tubular structure having a bottom. Numeral 2 denotes a metal substrate inside thereof, which has a hollow structure having a bottom like the metal base 1. Reference numeral 3 denotes a polymer layer for bonding 1 and 2, which is usually formed of an adhesive containing a (meth) acrylic monomer having an acidic group or a monomer liquid in which a (meth) acrylic polymer having an acidic group is dissolved. It is formed by curing an adhesive. The implantable dental implant is usually used by closing the upper part of the metal base with a stopper having a structure as shown in FIG. FIG. 3 shows an abutment to which a crown can be attached, which is attached to the implant after the stopper shown in FIG. 2 is removed. The implantable dental implant is operatively implanted under the mucosa in the jaw bone in the first operation, and after the implant and the bone are completely attached, the plug of FIG. 2 is removed in the second operation. The abutment shown in FIG. 3 is mounted thereon. In the implantable dental implant of the present invention, the calcium phosphate of the outer layer is selected from calcium hydroxyapatite, calcium phosphate orthophosphate or a sintered body composed of a mixture thereof. The metal substrate inside is made of titanium, a titanium alloy, a cobalt-chromium alloy, or the like. Preferably, the inner surface of the metal substrate is threaded, but need not be. The material of the plug used for the metal substrate is preferably the same as that of the metal substrate, but may be another metal or another material such as silicone rubber or plastic. The tip of the plug need not be in contact with the bottom of the inner surface of the metal substrate and may be shorter. The abutment mounted inside the metal base is preferably made of the same material as the metal base. When the inner surface of the metal base is threaded, the protruding portion of the abutment is threaded at the same pitch as in the case of the above-described plug. As another method of attaching the support to the metal substrate, there is an adhesive used in the present invention, an adhesive with another adhesive, or the like. It is also possible to mount the screw and the adhesive side by side. When the inner surface of the metal base is threaded, the plug can be used by being threaded so as to have the same pitch. A feature of the present invention is that the outer layer made of calcium phosphate and the metal substrate in the outer layer are fixed by a polymer having a (meth) acrylic monomer unit having an acidic group as a constituent unit. The acidic group in the polymer means a functional group capable of lowering the pH of water to 5 or less when contacted with water, (Wherein X represents F, Cl, Br or I) is a group. Among the above acidic groups As such a monomer unit having an acidic group, Wherein R ₁ represents H or CH ₃ , and Ra represents a (m + 1) -valent organic group having 2 to 40 carbon atoms. Y ₁ and Y ₂ are O, S or NRb (Rb is H or C 1 to C 1)
M represents an integer of 1 to 4, and k represents 0 or 1. The polymer containing the monomer unit represented by the formula (1) has excellent adhesive strength. In particular, when water resistance is required for the adhesive strength, Ra is preferably an organic residue having a valence of (m + 1) of 4 to 40. In the present invention, the polymer layer for fixing the outer layer of calcium phosphate and the metal substrate is formed by polymerizing and curing an adhesive containing a (meth) acrylate-based monomer which usually has an acidic group as described above. The outer layer and the metal substrate are fixed. The following compounds are exemplified as specific examples of the monomer. The monomer having an acidic group as described above is used in a mixture with a neutral (meth) acrylate monomer as a diluent described later in an amount of 0.5% by weight or more. Examples of neutral monomers include methyl (meth) acrylate, nityl (meth) acrylate, benzyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-hydroxythiethyl (meth) acrylate, ethylene glycol di (meth) acrylate, and triglyceride. Ethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 2,2-bis [(meth) acryloyloxy polyethoxyphenyl] propane t is an integer of 1 to 9, R is H or CH ₃ ], 2,2′-bis [4- (3-methacryloyloxy-2-hydroxypropoxy) phenyl] propane (sometimes referred to as Bis-GMA). And the like. As the polymerization initiator for polymerizing and curing these monomer compositions, tributyl borane and a peroxide-amine-sulfinate salt system disclosed in JP-B-56-33363 are preferably used in addition to the BPO-amine system. Further, since a filler such as quartz powder or glass powder may be added to the adhesive used in the present invention, an inorganic filler may be contained in the formed polymer layer. The polymer layer in the present invention is also formed by polymerizing and curing an adhesive obtained by dissolving a polymer having a (meth) acrylic monomer unit having an acidic group in a monomer that dissolves the polymer. . A polymer having a (meth) acrylic monomer unit having an acidic group can be formed by using the above-mentioned (meth) acrylic monomer having an acidic group as one component, but a monofunctional monomer is used in view of solubility. It is preferably used. Further, it is preferable that the amount of the monomer unit having an acidic group is contained in the polymer finally formed in an amount of 0.5% by weight or more as in the case described above. The monomer having an acidic group is preferably copolymerized with a neutral monofunctional (meth) acrylic monomer as described above, and the polymer thus formed is dissolved in various (meth) acrylic monomers. Therefore, it is dissolved at an appropriate concentration, and a polymerization initiator is added to form an adhesive. By polymerizing and curing such an adhesive, a polymer layer is formed and the calcium phosphate outer layer and the metal substrate can be integrated. Also in this case, various additives such as an inorganic filler may be contained in the polymer layer. Hereinafter, the present invention will be described in detail with reference to examples. Example 1 Example 1 A calcium hydroxyapatite sintered body having an outer diameter of 3.5 mmφ, an inner diameter of 2.0 mmφ, a bottom thickness of 1.5 mmφ, and a length of mm (relative density 97.5%, purity> 99%) )
Inside diameter 1.8mmφ (3.5mmφ only at upper part), thickness 0.4mm, length 8.
An implantable dental implant was prepared by adhering a hollow titanium alloy having a diameter of 9 mm and threaded at a pitch of 0.3 mm with an adhesive having the following composition to form a polymer layer. Adhesive composition Bis-GMA 13.6 parts by weight 1,4-butanediol dimethacrylate 12.1 {10-methacryloyloxydecyldihydrodiene phosphate 4.5} benzoyl peroxide 0.3 # silane-treated quartz powder 100ナ ト リ ウ ム Sodium benzenesulfinate 0.3 〃N, N-jetanol-p-toluidine 0.5 〃 On the other hand, the implant was threaded with the same titanium alloy used for the implant at the same pitch as the inner surface of the implant A stopper and an abutment were prepared. In FIG. 3, the a portion of the abutment is 4 mm, the b portion is 8.1 mm, the c portion is 2.8 mm, and the d portion is 3.5 mm. The implantable dental implant was implanted in the molar of a monkey, and the implant was observed for 6 months after the implantation and for 3 months after the crown was built on the abutment. Was. Example 2 An artificial tooth root was prepared in the same manner as in Example 1 except that an adhesive having the following composition was used. Adhesive composition 2.5 parts by weight of adhesive monomer represented by the following formula Methyl methacrylate 47.5 〃Polymethyl methacrylate powder 5 ト リ Trimethylborane 5 〃 The implantable dental implant was implanted in the molar of a monkey and observed for 2 months from the implantation. Did not. Example 3 An artificial tooth root was prepared in the same manner as in Example 1 except that an adhesive having the following composition was used. Adhesive composition Bis-GMA 17 parts by weight Neopentyl glycol dimethacrylate 13 {6-methacryloyloxyhexyl dihydrodiene phosphate 2.8} Silane-treated quartz powder 100 {Benzoyl peroxide 0.4 parts by weight Sodium benzenesulfinate 0 0.3 {N, N-diethanol-p-toluidine 0.4} One month after implanting the implantable dental implant in the molars of a monkey and constructing a crown on the abutment for three months from the implantation During the observation, no fluctuation or dropout of the implant was observed. Examples 4 to 5 In Example 1, an artificial agent was prepared in the same manner as in Example 1 except that the monomers shown in Table 1 were used instead of 10-methacryloyloxydecyldihydrodiene phosphate as the composition of the adhesive. Roots were made. As a result of conducting an animal experiment in the same manner as in Example 1, the same effect as in Example 1 was obtained. (Effect of the Invention) According to the present invention, a composite implant in which the calcium phosphate layer and the metal substrate are firmly integrated was obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing an example of a composite implant (for implantable dental use) according to the present invention, and FIG. 2 is used for closing the implant shown in FIG. FIG. 3 is a cross-sectional view showing an example of a plug to be provided, and FIG. 3 is a cross-sectional view showing an example of an abutment mounted on the implant shown in FIG.

Claims (1)

Claims: 1. A composite implant having a calcium phosphate layer on a surface in contact with a living body and a metal substrate provided inside the layer, wherein the calcium phosphate layer and the metal substrate are (Where X represents a halogen) A composite implant fixed by a polymer layer having a (meth) acrylic monomer unit having an acidic group selected from the group consisting of: (2) 3. The (meth) acrylic monomer unit has a general formula [However, R ₁ represents a hydrogen atom or a methyl group, and Ra has 2 to 40 carbon atoms. And Y ₂ are each O, S or NRb (Rb is a hydrogen atom or a carbon number 1-4)
M represents an integer of 1 to 4, and k represents 0 or 1.]
The composite implant according to claim 2, which is a monomer unit represented by the following formula: 4. The composite implant according to claim 3, wherein m is 1 in said general formula.