JPH03182241A - Manufacture of artificial dental root - Google Patents

Abstract

PURPOSE:To manufacture an artificial dental root of good organism compatibility and mechanical strength by taking the mold of the dental root by solidifying a specific resin on a dental root from which teeth are extracted, inserting a bone structure in the mold, and filling the mold with a paste composition for polymeric solidification. CONSTITUTION:An artificial dental root is manufactured by taking the mold of the dental root by solidifying a specific resin on a dental root from which teeth are extracted, filling the mold with a bone structure made of fiber strands and polymeric resin composition, and solidifying the polymeric resin composition by polymerization. The bone structure is made of fiber strands impregnated with thermoplastic resin or thermosetting resin. The polymeric resin contains as main ingredients polymeric monomer, ceramic of calcium phosphate family and polymeric catalyst. As the polymeric monomer, acrylic acid esters, urethane (metha)acrylic acid esters of mono- and poly-functional property are preferable. As the thermoplastic resin for fixing the shape of the strands, polymethacrylic acid methyl, polystyrene, and polyvinyl chloride or the like are preferable. As the thermosetting resin, those containing thermo-polymeric catalyst are preferable.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for manufacturing a high-strength artificial tooth root that can be easily and quickly produced and has excellent biocompatibility, using a fiber-reinforced composite material containing calcium phosphate ceramic. It is related to. The artificial tooth root of the present invention can be applied not only to artificial tooth roots, but also to prevention of alveolar bone resorption by filling into tooth extraction sockets, alveolar ridge formation to prevent alveolar ridge resorption, and filling of alveolar bone defects.

[Prior Art] Currently, treatments such as bridges and dentures are used to treat tooth extraction due to caries or alveolar pyorrhea. However, once a tooth is extracted, problems such as movement of the remaining tooth and recession of the alveolar bone occur, which tends to cause various inconvenient situations, and the above-mentioned treatments are essentially temporary. By the way, a more essential treatment is after tooth extraction**
Although it has been proposed to implant artificial tooth roots into bone, conventional artificial tooth roots have many clinical problems and are not yet an established treatment method that everyone can enjoy. The cause is not only problems with the material of the artificial tooth root itself, but also clinical techniques such as incision of the gingiva in the oral cavity, a place where there are many resident bacteria and it is difficult to maintain a clean condition, and damage to the alveolar bone. The problem is that it involves technically difficult procedures such as drilling holes and suturing the gums. Specifically, conventional artificial tooth roots are often made of materials with poor processability, such as various ceramics and titanium metal, and the patient's affected area is removed and buried to match the ready-made product made at the manufacturer's factory. There were a lot of things to put in. Furthermore, patients have a strong fear of this clinical procedure, which is one of the reasons for inhibiting the widespread use of artificial tooth roots. In order to improve this point, a proposal has been made (Japanese Patent Laid-Open No. 52-97288) to apply a ceramic implant to the tooth extraction socket immediately after tooth extraction. Because it takes a long time to sinter the alumina ceramic, it is impossible to leave the patient's wound open and wait for the artificial tooth root to be completed.The affected area must be sutured first and then re-incised when the patient visits the hospital again. there were. However, the oral cavity is constantly filled with bacteria, and it is not desirable to have to have many sutures and incisions.

[Problems to be solved by the present invention] In order to establish artificial tooth roots as a more reliable treatment method under difficult circumstances as described above, it is necessary to develop a simple and highly safe clinical procedure and to improve the material. There is a need for an artificial tooth root with excellent biocompatibility and mechanical strength, and a simple manufacturing technology.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present inventors have developed a method that reduces physical damage and fear of patients, simplifies clinical procedures, and has high strength and good biocompatibility. The present invention was completed with the aim of creating an artificial tooth root.

That is, the present invention has 1. An artificial artificial body characterized by applying a resin to an extracted tooth root to create a mold, filling the mold with a skeletal structure made of fiber strands and a polymerizable resin composition, and polymerizing and curing the polymerizable resin composition. How to make tooth roots.

2. A method for producing an artificial tooth root, in which the skeletal structure is obtained by impregnating fiber strands with a thermoplastic resin or a curable resin and arranging them to constitute the skeletal structure of the artificial tooth root.

3. The present invention relates to a method for producing an artificial tooth root, in which the polymerizable resin contains a polymerizable monomer, a calcium phosphate ceramic powder, and a polymerization catalyst as main components.

First, regarding the reduction of physical damage and fear of patients,
The aim was to create a surgical method that does not enlarge the tooth extraction socket beyond cleaning and curettage immediately after the tooth has been extracted, and can complete the implantation in -1 surgery. That is, it is a method in which an artificial tooth root having exactly the same shape as the root of an extracted tooth can be prepared and implanted as quickly as possible. Furthermore, the artificial tooth root used in this system is reinforced with a skeleton structure made of fiber strands at mechanically important positions, and is made of a fiber/powder-reinforced composite resin that has high strength and biocompatibility by incorporating calcium phosphate ceramics. It is an artificial ms made of material.

In other words, in order to accurately and easily create an artificial tooth root with the same shape as the tooth root of the extracted tooth, a mold of the tooth root is created by adhering heated and softened liquid or paste resin or thermoplastic resin to the extracted tooth root and hardening it. A skeletal structure consisting of fiber strands (
We devised a method for manufacturing an artificial tooth root by inserting a reinforcing fiber material, filling it with a paste-like composition, and polymerizing and hardening it. This artificial tooth root is based on a liquid and fluid polymerizable monomer, uses reinforcing fibers to ensure mechanical strength, and contains calcium phosphate ceramic to achieve good biocompatibility. A polymerization catalyst is blended in order to polymerize and harden the polymerizable monomer and fix the tooth root morphology.

In the method for manufacturing an artificial tooth root of the present invention, a mold-making silicone resin or the like can be used in addition to the liquid or paste resin used for making the mold of the artificial tooth root. However, thermoplastic resin is the most convenient method for making extraction dental molds in a short period of time. Any thermoplastic resin can be used as long as it has a softening point of room temperature or higher, preferably 50°C or higher, but after curing the polymerizable resin composition in a thermoplastic resin mold, the artificial tooth root is released from the mold. From the viewpoint of ease of processing, it is preferable to use a material that has poor compatibility with the polymerizable resin composition described below, that is, a material that has good solvent resistance to methyl methacrylate. For example, polyethylene, polypropylene, nylon, etc. are preferred. However, this is not the case if a mold release agent is used between the mold and the artificial tooth root. The method of using these thermoplastic resins is, for example, by heating a sheet with a thickness of 0.5 to 2 cm with a weak flame to soften the sheet, and while it is soft, quickly push the root of the extracted tooth. The sheet is tightly attached to the tooth root using silicone paste or fiber cloth that is softer than the sheet side (
A simple method is to lower the temperature of the sheet while pressing (pressure welding) and harden the sheet into the shape of the tooth root.

By the way, artificial tooth roots are subject to not only compressive and bending stress, but also
A metal pin is placed in the artificial tooth root to connect it to the crown of the tooth, and when force is applied repeatedly to the pin, stress is exerted that stiffens the artificial tooth root and causes it to crack or tear. A reinforced composite resin made only of powder is extremely strong against compressive stress, but weak against bending and tearing.

Therefore, it is necessary to take measures against bending stress and tearing stress even in the artificial tooth root used in the present invention. As a countermeasure, we investigated the reinforcement of artificial tooth roots with fibers, and found that reinforcement with short fibers was insufficient, but reinforcement with a skeletal structure consisting of long fiber bundles was superior. In other words, in order to resist bending stress, reinforcing fiber bundles in the shape of an umbrella bone in the direction of the side wall generatrix of the artificial tooth root, and reinforcing fiber bundles in the shape of a headband or zigzag near the outer periphery of the tooth root to resist tearing stress. was found to be effective. Regarding the arrangement of such reinforcing fibers, it is difficult to arrange individual fibers separately in the manner described above, so it is necessary to use the fibers as fiber bundles, or strands, and to impregnate the strands with resin. By this, the shape is fixed so that it can be hardened to make it easier to use, and can be selectively placed in a dynamically important position and easily reinforced at that position. This is called a skeletal structure.

The type of reinforcing fiber used in the present invention is not particularly limited, and includes glass fiber-1 carbon fiber, alumina fiber,
Inorganic fibers such as zirconia fibers, boron nitride, and metal fibers may be used, or organic fibers such as polyester, vinylon, aramid, nylon, acrylic, rayon, polypropylene, and polyethylene may be used. The surfaces of these fibers may be treated to improve compatibility with the polymerizable monomer described above and the resin for fixing the strand shape described below. These fibers are used as strands of 10 to 2000 monofilaments. The shape of the strands may be untwisted, lightly twisted string-like, or thin tape-like flat. If the strand is twisted too much, the strength of the composite resin as well as the strength of the strand itself will decrease, but the degree of decrease is such that there is no problem in practical use of this artificial tooth root. When twisting, 1m
The rotation may be repeated 200 times or less, more preferably 100 times or less. Regarding the width and thickness of the strand, it is important to consider operability, and if the strand is twisted, the thickness of the strand should be 0.1 to 3 mm, more preferably 0.1 to 2 mm. Anything within the range will be used. If the strand is flat, the thickness is 0.02~lam.
, more preferably 0.02~0.3am, width 0.1~
31-1, those with a particle size of 0.1 to 2 cm are preferably used. The length of the strands is determined by the size of the tooth root, so it cannot be generalized, but while the strands reinforce more than half of the generatrix and perpendicular lines of the artificial tooth root, their blending position stays inside the artificial tooth root and does not extend beyond the outside. A length that does not protrude is preferable.

The resin used in the present invention to fix the shape of the strands may be a thermoplastic, thermosetting or photocurable resin, but it must be compatible with the polymerizable monomers described below. As the thermoplastic resin, for example, amorphous polymers such as polymethyl methacrylate, polystyrene, polyvinyl chloride, etc. and/or polymers having poor solvent resistance to methyl methacrylate are suitable. Further, as the thermosetting resin or photocurable resin, one in which a thermal polymerization catalyst or a photopolymerization catalyst is blended with a polymerizable monomer is preferable. The strand shape fixing method involves impregnating the strand with the above resin.
After aligning the strands in a position and shape most effective for improving their strength in accordance with the shape of the hard tissue 111i, the impregnated resin is cured by heating or light irradiation to fix the shape of the strands. The amount of shape-fixing resin to be used should be such that it does not make the strands sticky or clumpy, and should be 0.1 to 10% of the weight of the strands.
Weight % is appropriate.

The polymerizable monomer used in the polymerizable resin composition for artificial tooth roots of the present invention is (meth)acrylic acid alkyl ester (
Alkyl group has 1 to 10 carbon atoms), 1 realkylene glycol di(meth)acrylate (2 to 20 carbon atoms), ethylene glycol oligomer: ) (meth)acrylate (
2-1Omer), bisphenol A di(meth)acrylate, 2.2-bis[p-(γ-methacryloquine-β-
Hydroxypropoxy)phenyl]propane, 2.2-
Monofunctional and polyfunctional such as di(4-methacryloxyboriethquinphenyl)propane (2 to 10 ethoxy groups in one molecule), trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, etc. and urethane (meth)acrylic esters which are reaction products of 2 moles of (meth)acrylate having a hydroxyl group and 1 mole of diisocyanate, specifically, Japanese Patent Publication No. 55-33687.
Monomers such as those disclosed in JP-A No. 56-152408 are suitable. Although these monomers may be used alone, it is preferable to use a mixture of two or more types of monomers. The monomer is contained in the composition in a proportion of 10 to 50% by weight.

Furthermore, the calcium phosphate ceramic used in the present invention has a phosphorus/calcium ratio of 1-1.7, such as hydroxyapatite, tricalcium phosphate, and brucite.
5. A firing temperature of 500 to 1250°C is preferable. This product is used as a powder, and its particle size is 0.1 to 500 μ-
It has a broad particle size distribution in the range of , and the average particle size is l-1
00 μm is preferable. The larger the amount of calcium phosphate ceramic used, the better the biocompatibility, but in order not to deteriorate the operability (paste properties) of the composition,
A range of 80% by weight is suitable. It is also possible to add an appropriate amount of filler such as alumina, zirconia, titania, quartz, and glass that is not harmful to living organisms.

Further, as a polymerization catalyst that can be used in the present invention, for example, as a photopolymerization type catalyst, JP-A No. 48-49875
No., JP-A-57-203007, JP-A-60-260
No. 02, JP-A-60-149603, JP-A-60-1
Conventionally known initiators described in Japanese Patent Application No. 97609, Japanese Patent Application No. 61-290780, and the like can be mentioned. Examples of the thermal polymerization catalyst include arbitrary initiators such as peroxides and azo compounds having an appropriate operating temperature range of 40 to 100°C. These catalysts are used in an amount of 0.1 to 5% by weight based on the polymerizable monomer.

Furthermore, stabilizers, fillers, etc. may be added to this artificial tooth root as necessary.

By the way, when using the artificial tooth root of the present invention, a pin made of titanium or the like may be implanted to connect the tooth root and the crown. The pin protrudes into the oral cavity, transmits intraoral stimulation to the contact area between the alveolar bone and the artificial tooth root, and may prevent adhesion between the artificial tooth root and the alveolar bone. Therefore, when implanting an artificial tooth root, a shaft with a lid is drilled inside the tooth root where a titanium pin will be inserted in the future, and after the artificial tooth root has adhered to the alveolar bone, the lid of the artificial tooth root is removed and the titanium pin is attached. You can also take

[Effects of the Invention] As described above, the present invention minimizes the physical damage and fear of the patient without further enlarging the extraction socket after tooth extraction or making an extra incision in the gingiva, making it safer. It is possible to provide a method for manufacturing an artificial tooth root that is reliably biocompatible and has excellent mechanical strength.

[Example] Example 1 and Comparative Example 1 As a calcium phosphate ceramic, hydroxyapatite with a phosphorus/calcium ratio of 1.68 was fired at 1100°C for 2 hours and ground in a ball mill.
Average particle size 40 with a broad distribution in the range of 00 μ-
A μ- powder was obtained. In addition, quartz powder (0.1 to 25 μm
After treating 100 parts by weight with 2 parts by weight of γ-methacryloxytrimethoxysilane and 150 parts by weight of toluene at 100°C for 3 hours,
Toluene was removed under reduced pressure to obtain a surface-treated quartz filler.

Meanwhile, 2 parts by weight of polymethyl methacrylate was added to 1 part by weight of ethyl acetate.
Strands (width 1.51, thickness O, lllllllll% approx. 20
Bundle of 0 monofilaments 1.7 mg/am) I
After 1 hour, the strand was pulled up and air-dried to produce a strand impregnated with polymethyl methacrylate. Furthermore, bisphenol A polyethoxy dimethacrylate (hereinafter referred to as D-2,6E) 4
0 parts by weight, 2.2 bis[p-(γ-methacryloxy β
-Hydroquine propoxy) phenylcopropane (hereinafter referred to as
30 parts by weight of triethylene glycol dimethacrylate (hereinafter referred to as 3G), 1 part by weight of camphorquinone, 1 M part of ethyl P-N,N-dimethylbenzoate, di-t-butyl hydroxy A polymerizable monomer liquid containing 0.05 parts by weight of toluene was prepared. A polymerizable resin composition was prepared by mixing and kneading 70 parts by weight of the above hydroxyapatite and 10 parts by weight of the above quartz filler into 20 parts by weight of this liquid.

In order to investigate the ura-strengthening effect of fibers on this composition, we investigated the flexural strength of a product obtained by polymerizing and curing this composition (Comparative Example 1) and the flexural strength of a product obtained by blending one of the above-mentioned fiber strands with this composition. compared. Each sample is 2X 2X
After filling a 30+gs prismatic sample production mold, it was cured by irradiating visible light for 1 minute with a dental light irradiator, and was immersed in 37°C water for a day and night to obtain a sample for bending strength measurement. As a result, the bending strength of the sample without fibers was 800 kg/c-, while the bending strength of the sample with fiber strands was 3000 kg/c-.
g/ctb”.

Example 2 A container with a diameter of 2 cm and a height of 2 cm is filled with a soft clay-like paste made by mixing talc with silicone oil. A polyethylene sheet with a thickness of i- and a diameter of 5 cm is sandwiched between a donut-shaped bottle set that grips the entire outer periphery of the sheet, and the central part of the sheet is heated with the flame of an alcohol lamp to improve the transparency of the sheet. When the sheet has softened, place it on a silicone base container,
Pressure contact was made by quickly pushing the root of an extracted human tooth.

After 30 seconds, the extracted tooth was extracted from the sheet and the sheet was removed from the silicone paste, yielding a mold that faithfully reproduced the shape of the tooth root. Into this mold, the summer strands of the example were inserted in the shape of an umbrella bone and a spiral shape, and the same composition as used in Example 1 was also embedded, and evenly spread from the outside of the mold with a dental light irradiator. The artificial tooth root was obtained by irradiating for a minute. The shape of this thing faithfully reproduced the shape of the root of a real extracted tooth.

Composition of hydroxyapatite sintered body Example 1 ^ Two types of samples with a diameter of 4 mm and a height! oIIll
12 cylinders each for the majority of 6 M breed adult dogs.
A total of 24 pieces were inserted, one for each book. After 3 months, the dog was sacrificed and the tissue surrounding the implanted sample was visually observed for necrosis, abscess formation, and drainage of the implanted sample.Then, the surrounding tissue was collected in one block, fixed, embedded, and stained. The surrounding tissue was then pathologically observed using an optical microscope. As a result, no abnormality was observed in all cases upon macroscopic observation. In addition, when observed under a microscope, the sample of Example 1 was in contact with the bone in most parts of the cortical bone, similar to hydroxyapatite.
The bones were compacted and laminated. This clearly shows that the artificial tooth root composition of the present invention is biocompatible with bone tissue.

Example 4 Three adult mongrel dogs were used, and the mandibular canines were extracted under general anesthesia. Next, a polyethylene sheet having a thickness of 11 was heated with an alcohol lamp to soften it, and the same operation as in Example 2 was performed to create a mold of the extracted tooth root. Next, perform the same operations as in Example 2 to create an artificial tooth root, polish one layer of the surface, disinfect it by soaking it in ethanol for 5 minutes, wash away the alcohol with sterile physiological saline, and insert it into the dog's tooth extraction socket. Then, the gingiva was sutured and the implantation was completed. Thereafter, during the 3-month observation period, there were no cases of ejection of artificial tooth roots.

Example 5 40 parts by weight of bisphenol A polyethoxy dimethacrylate, 2.2-bis[p-(γ-methacryloquinone β-
Hydroxypropoxy) phenyl] propane 30! I
Part i, 30 parts by weight of triethylene glycol dimethacrylate, 1.5 parts by weight of benzoyl peroxide, and 0.05 parts by weight of di-t-butylhydroxytoluene were added with the hydroxyl described in Example 1. A-paste was prepared by mixing 7 g of apatite powder and 1 g of quartz filler, 40 parts by weight of bisphenol A polyethoxy dimethacrylate, and 2.2-bis[p-(γ-methacryloxyβ-hydroxypropoquine)phenyl]propane. 30 parts by weight, 30 parts by weight of triethylene glycol dimethacrylate, 2.5 parts by weight of N,N-jetanol-toluidine
B-paste was prepared by mixing 6.5 g of the above hydroxyapatite powder and 1 g of quartz filler with 2.5 g of a monomer liquid consisting of 0.05 parts by weight of di-t-butylhydroxytoluene. Strands of high-strength vinylon (manufactured by Stock Rare, width 1.2mm, thickness 0.12am)
, bundle of about 150 monofilaments 1.4g+g/c
+a) was immersed in the photopolymerizable monomer described in Example 1 for 1 hour, the strand was pulled up, and the excess monomer was wiped off with paper to obtain a strand impregnated with the photopolymerizable resin. Insert the above strand in a spiral shape into a mold for creating a conical sample with a diameter of 611% and a height of 1 osv.
The shape was fixed using a dental tip irradiator. Next, a composition obtained by mixing 8-paste and B-paste was put into a mold, and a cylindrical stainless steel pin with a diameter of 4 ms was planted in the center to produce a prosthesis. Furthermore, for comparison, a prosthesis of the same shape without reinforcing strands was fabricated. Each is considered an artificial tooth root, and assuming that 80% of the artificial tooth root is retained in the alveolar bone, 80% of the prosthesis
was fixed in a dental composite range, and a 20 kg load was placed on each prosthetic metal pin at a 45 degree angle to the axis of the pin.
An actual load of 10,000 times was applied. As a result, no abnormalities were observed in the prosthesis reinforced with strands, but
Three obvious cracks were observed around the metal pins in the prosthesis without strands.

Claims (1)

[Claims] 1. Applying resin to the extracted tooth root to create a mold, filling the mold with a skeletal structure consisting of fiber strands and a polymerizable resin composition, and polymerizing the polymerizable resin composition. A method for producing an artificial tooth root characterized by hardening. 2. The method for producing an artificial tooth root according to claim 1, wherein the skeletal structure is a fiber strand impregnated with a thermoplastic resin or a curable resin and arranged to constitute the skeletal structure of the artificial tooth root. 3. The method for producing an artificial tooth root according to claim 1 or 2, wherein the polymerizable resin contains a polymerizable monomer, a calcium phosphate ceramic, and a polymerization catalyst as main components.