JPH0556145B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to a denture base made of a denture base body made of a novel material and a lining material having rubber elasticity fixed to the denture base body. <Prior Art> Polymethyl methacrylate (hereinafter referred to as PMMA) resin has been widely used as a conventional denture base material (for example, JP-A-58-201707). Such denture base materials are extremely hard and have poor attachment properties to the alveolar ridge, often causing the denture to wobble during mastication, cause unwanted tenderness, or fall off. Therefore, in order to eliminate such drawbacks, it has been conventional practice to form a lining material having rubber elasticity or flexibility on the alveolar contact surface of the denture base. Materials for such lining materials include those using soft fluorine resin (Japanese Patent Application Laid-open No. 55-21919), collagen (Japanese Patent Publication No. 57-50498), and silicone rubber (Japanese Patent Application Laid-Open No. 57-50498). (No. 58-54946), natural rubber, isoprene polymer (Japanese Unexamined Patent Publication No. 55-26923), styrene-butadiene thermoplastic elastomer (Unexamined Japanese Utility Model No. 101622, 1982), etc. be. <Problems to be Solved by the Invention> When PMMA is used as the denture base body, the following problems arise. That is, the PMMA denture base is molded using liquid methyl methacrylate (hereinafter referred to as MMA).
) a polymerization initiator is added to the monomer, and
PMMA powder is kneaded into a rice cake shape, which is then filled into a denture base space made of plaster and polymerized in hot water at approximately 100°C to 130°C or in a steam atmosphere. In this molding method, a considerable amount of unreacted MMA monomer remaining in the denture base is eluted from the denture base, and this monomer, polymerization initiator, and their decomposition products cause tissue damage and abnormalities such as cell proliferation have recently been reported. This has been confirmed and is a problem. On the other hand, when the above-mentioned materials are used as the lining material, the following problems arise. In the case of soft resin, its rubber elasticity is limited, making it unsuitable for maintaining attachments, and when it is deformed by local pressing force, it does not have the same restoring force as rubber. If a thin sheet is pressed against the mucosal surface of the denture base, it is difficult to fill the undercut portion of the retaining tooth, and sufficient retaining force cannot be obtained. Since silicone rubber is a vulcanized rubber, it is difficult to modify it once it has been vulcanized and molded. The present invention was made in view of these circumstances, and by using new plastics and thermoplastic elastomers as the denture base main body material and lining material, no special machinery is required.
This realizes a lining material that is easy to mold and modify. <Means for solving the problems> In the denture base according to the present invention, the denture base main body is made of polyethylene, polypropylene, polyethylene copolymer, or polypropylene copolymer, and the denture base main body The lining material fixed to the inner surface is an olefinic thermoplastic elastomer containing at least polyethylene or polypropylene as a hard segment, or the olefinic thermoplastic elastomer and styrene.
It is made of an elastic material made of a mixed material of thermoplastic elastomer made of ethylene-butylene copolymer. <Example> (a) Complete denture Figure 1 shows an example of the case where it is adopted as a mandibular complete denture 1, and 2 in the figure shows polyethylene, polypropylene,
A denture base body made of either a polyethylene copolymer or a polypropylene copolymer; 3 is a rubber bonded to a thickness of about 0.5 mm to 1.5 mm on the entire surface of the denture base body 2 facing the alveolar lining mucosa surface; Elastic lining material, 4, 4... is the denture base main body 2
These are artificial teeth made of resin or porcelain teeth that are fixed to the teeth. (b) Denture base body As the material for the denture base body 2, the following hard polyethylene or hard polypropylene can be used. Hard polyethylene: Shorex (registered trademark) F6080V (product number) manufactured by Showa Denko Co., Ltd., strength 350 Kg/cm ² , hardness (Shore D) 71, molding temperature 150°C to 280°C. Manufactured by Mitsui Petrochemical Industries Co., Ltd. Hi-Zex (registered trademark)
240M (product number), strength 400Kg/cm ² , hardness (Shore D)
66, molding temperature 150℃~280℃. Hardness polypropylene: Showa Denko Co., Ltd. manufactured by Showa Allomer (registered trademark), FA531 (product number), strength 385 Kg/cm ² , hardness (Rokuwell R) 104, molding temperature 150°C to 260°C.
Showaromer MA610H manufactured by the company, strength 360Kg/
cm ² , hardness (R) 106, molding temperature 150℃
or 260℃. Mitsui Petrochemical Polypro (registered trademark) J400 (product number) manufactured by Mitsui Petrochemical Industries, Ltd., strength 350 Kg/cm ² , hardness (Rockwell R) 100, molding temperature 150°C to 260°C. Manufactured by Ube Industries Co., Ltd.
UBE polypro (product name) J605-H (product number), strength
320Kg/cm ² , hardness (Rockwell R) 95, molding temperature
150℃ to 260℃. These polyethylene and polypropylene materials can be further mixed with a reinforcing material such as glass wool, and polyethylene copolymers and polypropylene copolymers can also be used. (c) Backing material The 3rd material of the lining material is an olefinic thermoplastic elastomer containing at least polyethylene or polypropylene as a hard segment, or this olefinic thermoplastic elastomer and SEBS.
A mixed material of thermoplastic elastomer consisting of a copolymer is used. Olefin-based thermoplastic elastomers consist of a hard segment made of polyethylene or polypropylene and a soft segment made of a homopolymer or copolymer such as butene, propylene, butadiene, etc., and have a softening temperature of 100°C or less and a JIS hardness (hereinafter simply referred to as hardness). About 20 or so
Has a wide range of hardness of 90. Tafmer (registered trademark) manufactured by Mitsui Petrochemical Co., Ltd. is a popular example of this type of olefin-based thermoplastic elastomer. This thermoplastic elastomer is an α-olefin thermoplastic elastomer, and there are some that contain polyethylene or polypropylene alone as a hard segment, and others that contain both polyethylene and polypropylene, and their hardness ranges from about 20 to 90. reach more than that. By blending these, the hardness can be adjusted within the usable range of about 40 to 80. The above olefinic thermoplastic elastomer is approximately
Since it begins to soften at around 70°C, a thermoplastic elastomer made of SEBS copolymer is blended with an olefinic thermoplastic elastomer to improve its temperature characteristics. Furthermore, this SEBS thermoplastic elastomer has better shape retention against temperature changes than the olefin thermoplastic elastomer, so by mixing the two, the overall durability is improved. This kind of SEBS-based thermoplastic elastomer is obtained by hydrogenating a styrene-butadiene-based thermoplastic elastomer, and for example, Lavalon (registered trademark) manufactured by Mitsubishi Yuka Co., Ltd. can be used. FIG. 2 shows the hardness-temperature characteristics when the mixing ratio of the olefin thermoplastic elastomer and the SEBS thermoplastic elastomer was changed. In the figure, the numerator indicates the proportion of the olefin thermoplastic elastomer, and the denominator indicates the proportion of the SEBS thermoplastic elastomer. As is clear from the figure
It can be seen that increasing the mixing ratio of SEBS-based thermoplastic elastomer suppresses softening from around 70°C. If SEBS thermoplastic elastomers have different hardnesses, the hardness will change due to mixing, so the hardness can be adjusted by this. However,
Since an increase in the SEBS-based thermoplastic elastomer reduces the adhesive strength to the denture base body, the mixing ratio actually needs to be about 75% or less. As a single olefin thermoplastic elastomer,
As mentioned above, it begins to soften rapidly at around 70°C, but since the majority of the lining material is shielded from the outside between the denture base body and the alveolar lining mucosal surface, this softens at around 70°C. It is not heated, and the temperature around the lining material that is exposed in the oral cavity may reach the temperature instantaneously, but the temperature will not be maintained to the point where it softens and deforms. However, for practical purposes, the olefin thermoplastic elastomer alone may be used. It is possible to mold the lining material 3 at a temperature of approximately 70° C. or higher. Therefore, it can be heated in hot water, steam, higher alcohol, or food oil. In particular, since edible oil can be heated to about 200° C., the fluidity of the lining material 3 is further improved when heated to such a temperature. Therefore, put it in a tube etc. to form a lump,
It is also possible to heat this. The hardness of the lining material 3 is preferably at least two types, hard and soft, depending on the location of use, and the hardness may be approximately 70 and the soft material approximately 50. (d) Adhesive When using a resin tooth made of PMMA resin as the artificial tooth 4, the artificial tooth 4 can be made of polyethylene, polypropylene, polyethylene copolymer,
It is necessary to adhere to the denture base main body 2 made of any resin such as polypropylene copolymer. This adhesive contains at least a copolymer containing polyethylene and methyl methacrylate (hereinafter referred to as MMA) or a copolymer containing polypropylene and MMA. The method for manufacturing this adhesive will be explained below. Polyethylene was heated and dissolved in toluene in a polymerization reactor, a predetermined amount of MMA and benzoyl peroxide (hereinafter referred to as BPO) were added to initiate radical polymerization, and graft polymerization was performed at 70° C. under a nitrogen atmosphere. After polymerization for 4 hours, the polymer solution was poured into a large amount of poor solvent (methanol in this example) to precipitate and separate the polymer. Separation of PMMA and MMA monomers was carried out using a Soxhlet extractor with ethyl acetate. Extraction was performed for 8 hours to dissolve and remove PMMA and MMA. As a result of analyzing the graft copolymer thus produced by infrared spectroscopy and other analysis methods, it was confirmed that the desired molecular structure was obtained. The following table shows three types of polyethylene-MMA graft copolymer products A,
It shows the degree of polymerization, degree of grafting, and grafting efficiency of B and C.

[Table] The unit of BPO concentration is ×10 ^-3 mol/degree of grafting and grafting efficiency are values calculated using the following formula. Grafting degree % = amount of grafted monomer / amount of backbone polymer x 100 Grafting efficiency % = amount of grafted monomer / amount of polymerized monomer x 100 The graft copolymer obtained as described above was mixed with 1.1.1. It was dissolved into a liquid adhesive. 1.1.1. Trichloroethane used as a solvent is suitable as this kind of solvent because it is non-toxic and easily evaporates with a boiling point of 74.1°C. In addition, chloride-based organic solvents such as chloroform, toluene, xylene, ethers, etc. can be used as the solvent. FIG. 3 shows the analysis results of copolymer product B by a differential thermal analyzer. The melting point of copolymer product B was thereby determined to be approximately 118°C. This means that an adhesive consisting of copolymer product B is applied to the base of the artificial tooth, and then
This means that when polyethylene, polypropylene, etc. that have been heated to 0.degree. Polypropylene was used in place of polyethylene and treated under the same conditions as the polymerization method described above (product B
MMA is polymerized under the following conditions) to form polypropylene and
A good adhesive was also obtained when a graft copolymer of MMA was produced and dissolved in a solvent consisting of ortho-xylene. Furthermore, the above-mentioned TAFMER (registered trademark) A4085 (product number), which is an olefin-based thermoplastic elastomer, was used as a backbone polymer and MMA was graft-polymerized under the same conditions as the above-mentioned polymerization method (conditions for product B) to obtain α-olefin. thermoplastic elastomer and
An adhesive can also be prepared by producing a copolymer of MMA and dissolving it in a solvent consisting of 1.1.1 trichloroethane. The graft copolymers of polyethylene and MMA and the graft copolymers of polypropylene and MMA were used as adhesive materials because they are compatible with the polyethylene, polypropylene, etc. that make up the denture base body.
This is done in consideration of compatibility with resin teeth made of PMMA. Therefore, the above copolymer is not limited to a copolymer of polyethylene or polypropylene and MMA, but also a copolymer of polyethylene and polypropylene.
It may be a terpolymer of MMA, or a copolymer of polyethylene or polypropylene and another substance such as vinyl acetate may be further copolymerized with MMA. (E) Method for manufacturing a denture base Figure 4 shows the method for manufacturing a denture base using the denture base body, lining material, and adhesive according to the present invention in the order of steps, and will be explained below with reference to the figures. . (A) A jaw model 5 obtained by taking an impression from a patient is formed using plaster 7 in a first flask 6. A hardening plastic material such as a slow polymerizing dental resin, a photopolymerizing resin material, a thermosetting resin material such as plastic clay is applied to the lining material formation site on the jaw model 5 (the entire surface of the complete denture shown in FIG. 1). A spacer 8 having a thickness of, for example, about 1 mm is formed. Since this spacer 8 corresponds to the part where the lining material will be formed later, it is treated, for example, by making the surface that contacts the thin part of the gum thicker. This spacer 8 is molded while it is in a plastic state and then hardened. (B) Wax 9 is raised in the shape of a denture base on jaw model 5 including spacers 8, and artificial teeth 4 made of PMMA resin are arranged on this. Such work is usually performed by dentists. (C) Cut out a predetermined width of the edge of the denture base formed with wax 9. This removed part 1
0 and 10, the above-mentioned cutting process is performed while taking into account the portions that are preferable to be used as lining materials because lining materials will be formed in the end. (D) Attach the spacer 8 to the removed portion 10 of the wax 9.
Filled with the same material as, for example, thermosetting plastic clay. The filling portion at the edge of the spacer 8 is formed to be relatively thick in order to clearly define the boundary line with the denture base body. Subsequently, plaster 11, 11 is poured around the filled portion on the edge of the spacer 8 to fix the spacer 8. (E) After applying a separating agent to the surface of the plaster mold of the first flask 6, the second flask 12 is placed on top of this, and the plaster 13 in a fluid state is poured into it. (F) After the plaster 13 has solidified, the first and second flasks 6 and 12 are stacked on top of each other, and the container 1 is
3 and immersed in hot water at about 100℃ for about 5 minutes. This melts the wax 9 and at the same time hardens the spacer 8. (G) The pair of flasks 6 and 12 are divided, and the wax 9 is removed by washing with hot water. (H) Flexible mold release films 14, 14 such as polyethylene are placed on the surfaces of the plaster molds of flasks 6, 12.
The denture base space between the films 14 is filled with a plastic material 15 such as clay. This plastic material 15 must at least maintain its shape after molding. (I) The flasks 6 and 12 are clamped and the plastic material 1
5 is molded into a shape that matches the denture base body.
(J) Separate the flasks 6 and 12, place the molded plastic material 15 on it, turn the flask 12 upside down, apply two-component silicone rubber to the surface of the plastic material 15, and harden it. A rubber layer 16 with a thickness of 2 mm is formed. Subsequently, another flask 17 is placed on top of the flask 12, and gypsum 18 in a fluid state is poured into it. The rubber layer 16 is later used as a mold when molding the denture base body, and if an undercut exists in the denture base body, the elasticity of the rubber layer 16 makes it easy to remove it. (K) After the plaster 18 has hardened, the flasks 12 and 17 are divided and the plasticizer 15 is removed together with the release films 14 and 14. An adhesive 20 is applied to the surface of the artificial tooth 4 exposed in the denture base space 19. (L) After the adhesive 20 has dried, the denture base body 2 is placed in the denture base space 19 using polypropylene, such as UBE polypro J605, heated to about 200°C and melted.
- Fill with H. In this step, a press molding method or an injection molding method can be used. (M) The flasks 12 and 17 are clamped and cooled to form the denture base main body 2 made of hard polypropylene, and at the same time, the artificial tooth 4 is fixed to the denture base main body 2. (l) Divide the flasks 12 and 17 and separate the denture base body 2.
The lining material 3 is heated and softened at a temperature of about 70°C or higher and then filled into the recess. A press molding method or an injection molding method can also be used in this step. However,
Since the molding temperature of this lining material 3 can be up to a minimum of about 70°C, it can be molded by heating in hot water, steam, or edible oil, thereby eliminating the need for a press molding machine or an injection molding machine. . After that, from the flask 6 to the spacer 8 in the process
Remove this and place it on flask 12. (O) Approximately 100℃ with flasks 6 and 12 compressed.
Heat and keep warm at 120℃ for about 5 to 10 minutes. In this way, both the polypropylene forming the denture base main body 2 and the lining material 3 are softened, and the adhesive strength between the two is improved. Such treatment also has an annealing effect at the same time. (P) After cooling the flasks 6 and 12, divide them, break the plaster, and take out the denture 21. Then lining material 3
The denture base body 2 has been treated with abrasive correction etc.
is polished, and the denture 21 is completed. Note that in the above steps, if the jaw model 5 does not have an undercut, steps (H) to (J) can be omitted. That is, flask 6 in step (G)
The spacer 8 is left in the plaster mold, and this is used as the mold for forming the denture base body. In the above examples, polypropylene was used as the material for the denture base main body 2, but the denture base main body 2 can also be formed by the same process when polypropylene copoly, polyethylene, or polyethylene copolymer is used. In either case, strong adhesive strength can be obtained for both the artificial tooth 4 and the lining material 3. In addition, as the artificial tooth 4, the above-mentioned
When using porcelain teeth instead of PMMA resin teeth, a recess is formed at the base of the porcelain tooth, and the material of the denture base main body 2 is filled into the recess at the same time as the molding time to mechanically engage the recess. Of course, no adhesive is required at this time. Furthermore, in addition to the above-described method, a lining material of a predetermined shape is first formed, and with this material placed on a jaw model, it is heated to a molding temperature in a denture base system forming space formed of plaster. It is also possible to form the denture base main body by injecting polyethylene, polypropylene, etc. in a fluidized state and simultaneously fix it to the lining material. (F) Partial Dentures and Attachments The manufacturing method described above is also beneficial when applied to the production of partial dentures or dentures with attachments. 5A and 5B show a partial denture 22, the lining material 3 has protrusions 23, 23 at both ends,
This is a maintenance tooth 24, 24 consisting of an adjacent natural tooth.
It comes into contact with the undercut of the denture and maintains the denture. 25 is the alveolar ridge. FIG. 6 shows an example of the stud attachment 26, in which 27 is a metal plate stud fixed to the tooth root 28, 3 is a lining material, and the attachment female 33 is used when forming the lining material 3. formed at the same time. 24 is a gingival part. FIG. 7 shows an example in which it is employed in the Darbo attachment 29, in which 30 is fixed to the retaining tooth 24 with a metal mail. 3 is a lining material, and the female mail 31 that holds the mail 30 therebetween is integrally molded with the lining material 3 at the same time. female mail 3
1 includes a metal ring 32 fixed to the artificial tooth 4.
is extended, and the mail 30 engages with this metal ring 32. Reference numeral 23 designates two protrusions formed on the lining material 3 so as to abut the undercuts of the retaining teeth 24 from the left and right sides of the attachment 29. <Effects of the Invention> According to the present invention, the following effects can be obtained. Since polyethylene, polypropylene, polyethylene copolymer, and polypropylene copolymer are used as the material for the denture base body, there is no harm to human tissue, and the phenomenon of unreacted monomer elution does not occur due to the manufacturing method, so conventional PMMA It is possible to realize a denture base body that is extremely superior in terms of safety and hygiene compared to denture bases. As the lining material, an olefinic thermoplastic elastomer containing at least polyethylene or polypropylene as a hard segment, or a mixed material of this olefinic thermoplastic elastomer and a thermoplastic elastomer consisting of a styrene-ethylene-butylene copolymer is used. It is extremely compatible with the denture base main body made of polypropylene or the like, and the two can be easily fused together by heat-pressure welding, resulting in extremely high strength. Since the lining material softens at temperatures above about 70°C, it can be molded by heating in hot water, steam, or edible oil. Therefore, a lining material of any shape can be easily produced without using a special machine. Since the hardness of the lining material can be set arbitrarily, it can be set to the optimum hardness suited to the case, and the problems of being too hard or too soft, which have been seen in conventional commercially available products, are solved. In other words, lining materials having partially different hardnesses can be used depending on the operating characteristics in the oral cavity. At this time, the interface between materials of different hardness and hardness is completely integrated and continuous. In addition, when replenishing and correcting, if the lining material is softened and the same material is softened and pressure-welded to it, the two can be easily welded, so the correction can be carried out as desired. Since a thermoplastic elastomer containing at least polyethylene or polypropylene is used as the hard segment as the lining material, the properties of polyethylene or polypropylene provide suitable wettability to saliva, resistance to oral bacteria contamination, resistance to erosion, and food coloring. It is possible to take advantage of the difficulty of dyeing due to other materials, etc., and improve the properties as a lining material. The lining material does not permanently change its rubber elasticity and is firmly adhered to the denture base body, so it can maintain a stable attachment function with strong suction even after long-term use. Since the lining material can be formed into any shape, it can be used not only as a lining material for complete dentures, but also as a body for attachments such as Dalboa attachments, studs, and attachments. becomes possible. Since the above-mentioned filament supports and fixes the male portion using the rubber-like elasticity of the lining material, there is no risk of its supporting function decreasing, and on the contrary, it absorbs the impact applied to the denture, reducing the burden placed on the alveolar ridge. be able to. Furthermore, by bringing the lining material into contact with an intraoral undercut such as a retaining tooth undercut, the retaining force of the denture can be strengthened.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a denture base according to an example of the present invention, and FIG. 2 is a hardness-temperature characteristic curve diagram when the mixing ratio of the olefin thermoplastic elastomer and the SEBS thermoplastic elastomer is changed. FIG. 3 is a characteristic diagram showing the measurement results of the copolymer product using a differential thermal analyzer; FIGS. Figure 5A is a top view showing one shape of the partial denture, Figure 5B is a cross-sectional view of Figure 5A, and Figure 6
The figure is a sectional view showing another shape, and FIG. 7 is a sectional view showing still another shape. 1... Complete denture, 2... Denture base body, 3... Lining material, 4
...artificial teeth.

Claims (1)

[Claims] 1. A denture base body made of polyethylene, polypropylene, polyethylene copolymer, or polypropylene copolymer, and an olefinic thermoplastic elastomer containing at least polyethylene or polypropylene as a hard segment, or a combination of the olefinic thermoplastic elastomer and styrene, ethylene, and butylene. A denture base made of a mixed material of thermoplastic elastomer made of a polymer, and comprising an elastic lining material fixed to the inner surface of the denture base main body.