JPH0236858A - Supplement device of plastic material for dental plate - Google Patents

Abstract

PURPOSE:To prevent the generation of bubble and shrinkage cavity in the polymerization of a denture base material by filling the same material as the denture base material in a space within a cylinder formed by pressing a piston, and supplementing the denture base material to dental plate forming space by means of the spring force of a spring body. CONSTITUTION:A rice cake type PMMA resin 14 is injected with pressure through a nozzle port 16 by means of an injection device in the state in which upper and lower bonnet flasks 9, 18 are compressed. The PMMA resin 14 is filled in a denture base forming space 15 and further injected into a supplement device 1. In the supplement device 1, a piston 4 is pressed by the PMMA resin 14, and a coil spring 7 is compressed and stopped at a position where the rear end to a regulating body 6 is made into contact with the cylinder 2 rear end and stopped. The PMMA resin 14 is thus filled in the denture base forming space 15 and the supplement device 1, and is subjected to heating and polymerization hardening by means of an autoclave after the nozzle port 16 is shut down and closed. At the initial period of the polymerization hardening, the piston 4 of the supplement device 1 is never pressed even if the PMMA resin 14 is expanded, so that the pressure of the denture base forming space 15 is maintained at a high condition, never causing bubble and shrinkage cavity even if a polymerization shrinkage occurs.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a replenishment device for plastic material for denture bases.

<Prior Art> Conventionally, a replenishment device for replenishing plastic +4 resin, such as polymethyl methacrylate (PMMA) resin, for forming a denture base is known (Japanese Utility Model Application Publication No. 145519/1983).

Furthermore, a technique is also known in which a lining material made of a plastic material, such as a thermoplastic elastomer, is adhered to the mucosal surface of the denture base (Japanese Patent Laid-Open No. 62-342).

<Problems to be Solved by the Invention> PMMA powder is kneaded with liquid methyl methacrylate (+1 MMA) monomer to form a plastic state (rice cake-like), then placed between plaster molds, compressed, and heated at approximately 100'C to 130°C. When heated in hot water or steam for a certain period of time, the PMMA resin polymerizes and hardens to form a denture base. At the initial stage of polymerization, the resin expands due to boiling of the MMA monomer, thermal expansion of the PMMA resin, etc., but then contracts, causing deformation. A device for replenishing PMMA resin during contraction was developed in the above-mentioned Utility Model 6.
Although this is a device disclosed in Japanese Patent No. 1145519, there is no mechanism for stopping the piston from being pushed. That is, PMMA resin expands in the initial stage of its polymerization, and at this time there is a risk that bubbles or cavities may be generated. Therefore, it is necessary to control this expansion, but this is not possible with the above-mentioned invention.

Furthermore, the invention disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 62'-342 is
A backing material made of thermoplastic elastomer is bonded at the same time as the PMMA resin is polymerized and cured by heating.
This thermoplastic elastomer also thermally expands when heated and contracts when cooled. This causes a problem in that bubbles and cavities are generated in the lining material as well.

<Means for Solving the Problems> The present invention solves the above-mentioned problems by applying a denture base material in a plastic state to a denture base forming space formed of plaster in a pair of stacked flasks. A replenishing device for replenishing the denture base forming space with the same feed as the denture base material during filling and heat forming, the device comprising: a cylindrical cylinder with an open front end and a closed rear end; a regulating body formed at the rear end of the piston and regulating a maximum pushing distance of the piston, and interposed between the piston and the rear end of the cylinder,
a spring body that elastically presses the piston toward the front end of the cylinder and whose length at maximum compression is approximately equal to the length of the regulating body; The same material as the described tooth base material is filled and replenished into the denture base forming space by the spring force of the spring body.

<Function> By filling the cylinder with the plastic material for the denture base, the piston is pushed to the maximum pushing position, and further pushing is prevented by the regulating body. When thermally polymerizing and curing PMMA resin as a plastic material, or when thermally adhering a lining material made of thermoplastic elastomer I-mer as a plastic material, even if thermal expansion force is generated in these materials, this pressure will cause the screws to 1 to 1 are not pushed further. That is, the volume of the denture base forming space is changed, and this space is maintained at a high pressure state. This prevents the formation of bubbles or cavities in the PMMA resin.

When the PMMA resin shrinks during polymerization, the -H1 resin is replenished from the replenishing device to ensure accurate molding.

When bonding the lining material by heating, the inside of the denture base forming space is maintained at high pressure as described above, so that the adhesive strength with the denture base increases. Furthermore, if the lining material shrinks during slow cooling after heating, the same material is replenished from the replenishment device, thereby suppressing the formation of air bubbles and cavities.

<First Embodiment> In FIGS. 1 and 2, reference numeral 1 indicates a replenishing device according to a first embodiment of the present invention, and is an example in which PMMA resin is used as the denture base material. 2 is a cylindrical metal cylinder whose front end is open and the rear end is closed with a screw 3; 4 is a metal piston that slides inside the cylinder 2; and a seal body 5 made of Teflon rubber on its front end surface. is covered. 6 is a regulating body formed on the rear end side of the piston 4;
The maximum pushing distance of the piston 4 is regulated. Actually, the piston 4 and the regulating body 6 are constituted by a cylindrical body with a closed front end and an open rear end. 7 is piston 4 and cylinder 2
A spring body, for example a coil spring, is interposed between the piston 4 and the rear end, and the front end engages with an engaging portion 8 formed on the back surface of the front end of the piston 4, and the rear end is fixed to the screw 3. There is. The reason why the piston 4 is fixed to the cylinder 2 via the engaging portion 8, the coil spring 7, and the screw 3 is to prevent the piston 4 from jumping out in front of the cylinder 2 due to the elasticity of the coil spring 7.

Here, the length of the regulating body 6 is set to be approximately equal to the length of the coil spring 7 at maximum compression. When the piston 4 is pushed into the cylinder 2 to the maximum extent, that is, when the rear end of the regulating body 6 comes into contact with the rear end of the cylinder 2, the coil spring 7 is compressed to the maximum.

The method of using the replenishing device having the above structure will be explained below with reference to FIGS. 3 to 5. The figure shows the case of manufacturing a mandibular complete denture, and in FIGS. 3 and 4, a stone/K jaw model 10 taken from a patient in a mandibular flask 9 is embedded in plaster 11. 12 is a mucous membrane surface on the surface of the jaw model 10. Reference numeral 1 denotes the above-mentioned replenishment device placed in the center of the case and about half embedded in the plaster 11, and its tip is connected to the center of the case on the mucous membrane surface via a runner 13. Through this runner 13, the PMMA resin 4 is replenished into the denture base forming space 15 (FIG. 5) located above the mucosal surface 12. The reason why the replenishment device 1 was set at the center of the denture was because
This is due to the fact that shrinkage is likely to occur in this part and that the outer part undergoes polymerization and hardening most slowly. 16 is PMMA resin 14
The nozzle port 17 into which PMMA resin is injected is a sprue carved into the plaster surface for introducing the PMMA resin 14 into the denture base forming space 15.

The upper flask 18 is superimposed on the lower flask 9 having such a structure (FIG. 5). Plaster 19 is placed in the upper flask 18.
is filled and molded into the shape of a good and auspicious denture. 20 is an artificial tooth embedded in plaster 19. The denture base forming space 15 is formed by a proper method through wax build-up on the jaw model IO and subsequent waxing process.

With the upper and lower lid flask 9.18 compressed, open the nozzle port 16.
PMMA resin 14, that is, PMMA powder and liquid M
A resin prepared by mixing MA monomers and further adding a polymerization initiator and the like is injected while applying pressure using an injection device or the like. The PMMA resin 14 fills the denture base preparation space 15 through the sprue 17 and is further injected into the replenishment device 1 through the runner 13 . In the refilling device 1, the screw 1-4 is pressed by the injected PMMA resin 14, the coil spring 7 is compressed, and the rear end of the regulating body 6 comes into contact with the rear end of the cylinder 2 and stops. Stop.

In this state, the denture base forming space 15 and the replenishing device 1 are filled with a capacity of PMMA resin 14,
Further injections are not possible. In this state, the nozzle port 16 is shut off and closed (this configuration is not shown, but a check valve or the like can be used), and the tube is placed in a pressure cooker or the like and heated to approximately 100°C.
It is heated to 130°C to polymerize and harden.

At the initial stage of polymerization and hardening, even if the PMMA resin 14 expands, the piston 4 of the replenishing device 1 is not pressed any further, so the pressure in the denture base forming space 15 is maintained at a high level.
Even if subsequent polymerization shrinkage occurs, there is no risk of generation of bubbles or cavities. When the pressure in the denture base forming space 15 decreases during polymerization contraction of the PMMA41 resin 14, the PMMA resin 14 is replenished from the replenishing device 1 into the denture base forming space 15, thereby preventing deformation due to contraction.

FIG. 6 shows a modification of the replenishing device 1, in which a regulating body 6' is formed in the shape of a column at the center of the piston 4, and a coil spring 7 is placed around the outer periphery of the regulating body 6'. With this configuration, when the coil spring 7 is compressed to the maximum, the rear end of the regulating body 6' comes into contact with the screw 3, and further pushing of the piston 4 is prevented.

With the replenishment device configured as above, PMMA
By replenishing the resin 14 when it polymerizes and shrinks, a high-precision denture without shrinkage deformation can be manufactured. At the same time, since the denture base forming space 15 is always maintained at a high pressure, it is possible to prevent air bubbles and cavities from forming on the denture.

<Second Embodiment> In FIGS. 7 and 8, reference numeral 21 indicates a replenishment device according to a second embodiment of the present invention, which is a denture made of a thermoplastic elastomer that is adhered to the mucosal surface of the denture base as a denture base material. This is an example using floor covering material. 22 is a cylindrical metal cylinder whose front end is open and the rear end is closed with a screw 23; 24 is a metal piston that slides inside the cylinder 22; a seal body 25 made of Teflon rubber is attached to the front end of the cylinder; ing. 26 is a semicircular groove carved in the front part of the piston 24, and 27 is a regulating body formed on the rear end side of the piston 24 to regulate the maximum pushing distance of the piston 24. In reality, the piston 24 and the regulating body 27 are constituted by a substantially cylindrical body with a closed front end and an open rear end. 28 is a spring body, for example a coil spring, interposed between the piston 24 and the rear end of the cylinder 22, the front end of which is engaged with a retaining portion 29 formed on the back surface of the front end of the piston 24, and the rear end of which is It is fixed to the screw 23. coil spring 2
8 was fixed to the piston engaging portion 29 and the screw 23 because
This is to prevent the piston 24 from jumping out to the front of the cylinder 22 due to the elasticity of the coil spring 28.

Here, the length of the regulating body 27 is set to be approximately equal to the length of the coil spring 28 at maximum compression, as in the above-mentioned embodiment. Therefore, the piston 24 is at most the cylinder 22
When pushed in, that is, when the rear end of the regulating body 27 contacts the rear end of the cylinder 22, the coil spring 28 is compressed to the maximum. 30 is a piston fixing body screw attached to the cylinder 22, and when screwed in, it hits the groove 26 of the screw I/N 24, and the piston 24
to be fixed. This screw 30 fixes the piston 24 at the maximum pushed position. Reference numeral 31 denotes a replenisher made of the same material as the lining material filled in the inner space of the cylinder 22 formed by the piston 24 being pushed into the cylinder 22, and made of, for example, an olefin thermoplastic elastomer. This replenisher 31 has a softening point of about 70°C. 32 is a runner made of the same material and placed at the tip of the replenisher 31.

The method of using the replenishing device 21 having the above structure will be explained below with reference to FIGS. 9 to 11. The figure shows the case where a mandibular complete denture is made in the same way as in the previous example. In FIGS. 7 and 10, 33 is a mandibular flask, and a plaster jaw model 34 taken from the patient is embedded in plaster 35. ing. 36 is
This is the mucous membrane surface of the jaw model 34. Reference numeral 37 is a lining material with a thickness of approximately 1 mm placed on the mucous membrane surface 36, and is molded into a shape along the surface of the mucosal membrane surface 36 by being heated and softened with hot air or the like. This lining material 37 is formed from an olefin thermoplastic elastomer. Reference numeral 21 denotes a replenishment device placed in the center of the case and buried in plaster 35 with only the head of the screw 30 remaining, and the tip of the runner 32 is welded to the lining material 37. The reason why the replenishing device 21 is placed in the center of the denture is that this part is the last to harden and bubbles and cavities are likely to occur.

After the screws 30 are removed and adhesive is applied to the surface of the backing material 37, a rice cake-shaped PMMA resin 38 is placed on the backing material 37. The upper lid flask 39 is placed on top of this, and the PMMA resin 38 is deformed by applying finger pressure two to three times. After that, the upper and lower lid flasks 33 and 39 are clamped,
It is placed in a pressure cooker and heated to approximately 100° C. to 130° C., and the r-' MMA resin 38 is polymerized and cured, and at the same time, the lining material 37 and the PMMA resin 38 are bonded together. The upper lid flask 39 is filled with gypsum 40 to form a good and auspicious shape of the denture. 41 is plaster 4
This is an artificial tooth embedded in 0.

At the initial stage of polymerization and hardening due to heating, the PMM and lubricant 38 expand, but the pressure does not push the piston 24 in the refilling device 21 beyond its stop position, so the denture base forming space 42 is maintained in a high pressure state. be done. Therefore, there is no risk of air bubbles or cavities entering the denture base due to pressure drop. Even if polymerization shrinkage occurs thereafter or shrinkage occurs due to temperature drop, the lining material 37 is pressed by the elasticity of the coil spring 28 from the replenishing device 21 and replenished, so the pressure applied to the lining material 37 is reduced. 13) The PMMA resin 38 and the lining material 37 are still free from air bubbles and cavities. According to experiments, the amount of lining material 37 that was adhered to the mucosal surface of the denture base was about 6 g, and the amount of the lining material made up of refilling device 21 was about 1 g. Replenishment of the lining material 37 is carried out during polymerization shrinkage of the PMMA resin and when the flask is taken out from the pressurized pot and allowed to cool naturally, and continues until the lining material 37 cools to about 70°C.

In the above two embodiments, one base of the denture was explained, but the object of the present invention is an orthodontic appliance mouthpiece,
It can be used for molding prosthetic materials in the oral cavity, such as actiment jaw prosthetics, and the term denture base is a concept that includes these.

<Effects of the Invention> According to the present invention, the denture base material is replenished from the replenishing device when the denture base is polymerized and hardened or when the lining that forms a part of the denture base is heated. Even if the denture base contracts during post-cooling, there is no risk that the inside of the flask will become pressureless, and the generation of air bubbles and cavities is suppressed.

Particularly when the denture base material is PMMA resin, deformation due to polymerization shrinkage has been a problem in the past, but by using the refilling device according to the present invention, the denture mucosal surface shape matches the alveolar ridge in the patient's mouth with high precision. This makes it possible to obtain even better wearability.

In addition, if the denture base material is a lining material, it will shrink when cooled after heating, and the space inside the flask will become pressureless. Furthermore, there will be a shortage of material for the lining material, which may cause air bubbles and cavities to occur. However, according to the present invention, the lining material is constantly pushed out from the replenishing device under pressure, and there is no risk of bubble formation. At the same time, a lining material having a surface shape matching the mucosal surface can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the first embodiment of the present invention, Fig. 2 is a partially cutaway sectional view corresponding to line A-A in Fig. 1, Fig. 3 is a front view of the lower lid flask, and Fig. The figure is a cross-sectional view taken along the line B-B in FIG. 3, FIG. 5 is a cross-sectional view showing a state in which the top-lid flasks are overlapped, and FIG. 6 is a modified example of the replenishing device according to the first embodiment. 7 is a perspective view of the second embodiment of the present invention, FIG. 8 is a partially cutaway sectional view corresponding to line C-C in FIG. 7, and FIG. 9 is a partially cutaway sectional view of the lower cover. Front view of flask, No. 10
The figure is a cross-sectional view taken along the line IJ-D in FIG. 9, and FIG. 11 is a cross-sectional view showing a state in which the flasks with upper lids are overlapped. 1.21...Replenishment device 2,22...Cylinder 4.24...Piston 6,27...Regulating body 7.2B...Coil spring 3.23...Screw 10.34...・Jaw model 1
2.36...Mucosal surface 13.32...Runner 1
5.42... Denture base formation space 9.33... Lower lid flask 18.39... Upper lid flask 11.19, 35.40... Plaster 14.38... PMMA resin 30... Hiss 37・
・・Backing material

Claims (4)

[Claims] (1) When filling the denture base material in a plastic state into the denture base forming space made of plaster in a pair of overlapping flasks and heat forming it, the same denture base material as the above denture base material is poured into the denture base forming space. A replenishment device for replenishing materials, which includes a cylindrical cylinder with an open front end and a closed rear end, a piston that slides inside the cylinder, and a cylinder formed at the rear end of the piston that controls the maximum pushing distance of the piston. A regulating body is interposed between the piston and the rear end of the cylinder to elastically press the piston toward the front end of the cylinder, and the length at maximum compression is approximately equal to the length of the regulating body. the same material as the denture base material is filled into the inner space of the cylinder formed by the pushing of the piston, and is replenished into the denture base forming space by the spring force of the spring body; A replenishing device for plastic material for denture bases, characterized by (2) The denture base plastic material replenishing device according to claim 1, wherein the denture base material is made of polymethyl methacrylate resin. (3) A piston fixing body is provided for fixing the piston to the cylinder when the piston is in the maximum pushing position regulated by the regulating body, and the piston is pushed in when the piston is fixed by the piston fixing body. 2. The apparatus for replenishing a plastic material for a denture base according to claim 1, wherein the inner space of the cylinder is filled with the same material as the denture base material as a replenishment material. (4) Replenishment of the plastic material for denture base according to claim 3, wherein the plastic material for denture base is a denture base lining material made of a thermoplastic elastomer that is adhered and formed on the mucosal surface of the denture base. Device