JPH0240964Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention provides a molding material suitable for use in a denture base molding device, particularly a device that molds a denture base by press-fitting a molding material into a flask by injection molding. The present invention relates to a filling confirmation member.

<Prior art> Polymethyl methacrylate (hereinafter referred to as PMMA) has conventionally been used as a denture base molding material. For molding methods using such materials, liquid methyl methacrylate (hereinafter referred to as MMA) is used.
After kneading PMMA powder with the monomer to make it into a plastic state, that is, a mochi-like state, this was filled into a denture base forming space previously formed using plaster in a certain flask, and heated at about 100°C in boiling water or the above-mentioned pressure cooker. The rice cake-like PMMA is polymerized and solidified by heating to ~300°C.
A method of injecting and press-fitting such a rice cake-like PMMA into a flask using an injection molding method has already been proposed due to its simplicity and speed of operation (for example,
−40073). In such a method, a sprue hole and an air vent communicating with the denture base forming space are formed in the plaster mold, and the nozzle of an injection molding machine is applied to the sprue hole to inject the molding material. If the sprue holes and air vents are left open after injecting the molding material, the injected material may escape from these holes to the outside of the flask, or the internal pressure of the injected material may decrease, causing problems during polymerization and solidification. There is a problem in that the amount of shrinkage increases. The shrinkage of such denture bases is usually about 1.8% to 1.8% for PMMA.
2.0%, weight approximately 0.2g to 0.3g per complete denture
That's about it. Incompatibility of the denture base with the alveolar ridge due to shrinkage has become a problem in recent years, as it causes poor adhesion of the denture, tooth movement, and tenderness during mastication.

<Problems to be solved by the invention> The invention uses an injection molding method to prevent the molding material injected into the flask from escaping to the outside, maintain the internal pressure of the material, and complete the filling of the material. This is to realize a molding material filling confirmation member that can confirm.

<Means for solving the problem> In order to seal the molding material press-fitted into the flask and maintain its internal pressure, the present invention provides a sprue hole closing valve at the sprue hole entrance of the flask, and a sprue hole closing valve at the end of the air vent. A molding material filling confirmation member is provided on the flask in which the air vent is located. It is constructed so that it protrudes from the top.

<Operation> The molding material injected into the flask through the sprue hole closing valve flows into the denture base preparation space through the sprue hole and fills it, and then flows into the air vent and presses the rear end of the confirmation member. . The pressed confirmation member moves slightly to cause its front end to protrude outside the flask, and at the same time acts as a blocking member that prevents the molding material from being discharged out of the flask. The molding material thus injected into the flask is sealed and maintained at an internal pressure equal to the injection pressure.

<Example> In FIGS. 1 and 2, 1 confirms that the denture base forming space 2 (FIG. 3) has been filled with the rice cake-shaped PMMA resin 3, and the flasks 4 and 5 of the resin 3.
This is a confirmation member that functions to prevent discharge to the outside. This confirmation member 1 consists of a cylindrical front end 6, a rear end 7, and a large diameter part 8 in between, and is housed so that it can move within the flasks 4, 5 internal space 9 by a certain distance in the left and right directions in the figure. The rear end 6 faces the air vent 10, and the front end 7 faces the outside of the flasks 4, 5. The space 9 has a cylindrical space portion slightly larger than the front end portion 6 and the rear end portion 7 on which the front end portion 6 and the rear end portion 7 slide, and a large diameter portion 8 on which the large diameter portion 8 slides.
The confirmation member 1 consists of a large-diameter space portion whose width is larger than the width of the large-diameter portion 8, and therefore, the confirmation member 1 is
It is possible to move back and forth a certain distance within the space 9. Therefore, as shown in FIG. 2, when the air vent 10 is filled with the rice cake-shaped PMMA resin 3, the confirmation member 1 is pushed outward from the flasks 4, 5 by the pressure, and the other end protrudes outside the flasks 4, 5 and stops. . This protrusion confirms that the denture base forming space 2 and the air vent 10 are filled with the cake-like PMMA resin 3. At the same time, the rice cake-shaped PMMA resin 3
is prevented from moving by the confirmation member 1. still,
The confirmation member 1 is made of an elastic material such as rubber, and its large diameter portion 8 is brought into elastic contact with the wall surface of the inner space 9 of the flasks 4 and 5, and supported to the extent that it does not move due to its own weight or a slight force. For example, the filling of the molding material can be known more reliably.

FIG. 3 shows the surface shape of one flask 4,
A sprue hole closing valve 12 is made of an elastic material such as rubber and comes into contact with the nozzle of the injection molding machine. 13
2 is a sprue hole, and 2 is the above-mentioned denture base forming space formed of plaster 14, in which artificial teeth 15, 15, . . . are embedded. The wall surface of the denture base forming space 2 matches the shape of the outer surface of the denture base. The air vent 10 is carved in the denture base forming space 2 at a position where the cake-shaped PMMA resin 3 finally reaches. Reference numerals 16, 16, . . . indicate a rice cake-shaped PMMA resin replenishment device disposed at a position facing the denture base forming space 2, particularly in an area where the denture base is likely to contract, for example, adjacent to both ends on the tongue side, with a reservoir 17 interposed therebetween. . Reference numeral 5 designates another flask that is superimposed on the flask 4, and both are clamped together with bolts or the like through screw holes 18, 18, . . . . The other flask 5 is filled with plaster, similar to the first flask 4, and a jaw model taken from the patient is formed using the plaster.

4 to 6 show the sprue hole closing valve 12.
19 is a cut in the center of the sprue hole closing valve 12 that penetrates from the surface located outside the flasks 4, 5 to the surface located inside the flasks 4, 5, and a cut is made in the direction inside the flasks 4, 5. It is formed so that it becomes narrower as it goes. A notch 19 is provided on the surface located outside the flasks 4 and 5.
A circular recess 20 having a diameter approximately equal to that is provided, and the nozzle 21 of the injection molding machine comes into contact with this. twenty two
is an intermediate protrusion formed on the outer periphery of the sprue hole closing valve 12, and as shown in FIG. Fixed. 24, 24...
In this case, the sprue hole closing valve 12 has four holes circumferentially on the outer periphery.
This is a concave groove. The sprue hole closing valve 12 having such a structure can be made of rubber having a JIS hardness of about 40 to 80.

To explain the function of the sprue hole closing valve material 12, the nozzle 21 is pressed against the circular recess 20,
When the rice cake-shaped PMMA resin 3 is injected with a predetermined pressure, the notch 19 is expanded by this injection pressure, creating an opening, through which the rice cake-shaped PMMA resin is injected.
The resin 3 is made to flow into the sprue hole 13. The concave grooves 24, 24, . . . act so as to be pressed down by the injection pressure to facilitate opening. Mochi-shaped
When the filling of the PMMA resin 3 is completed, the injection press-fitting is stopped. The above filling end time is confirmed by confirmation member 1.
Judgment is made by the protruding movement of the Thereafter, when the nozzle 21 is left in contact with the sprue hole closing valve 12 for a while, the sprue hole closing valve 12 returns elastically and the notch 19 is closed. Thereafter, the nozzle 21 is separated from the sprue hole closing valve 12.

FIG. 7 shows the replenishment device 16, which is made of a hard material such as plastic or metal and has a cylinder 25 with an opening at one end.
, a piston 26 housed in the cylinder 25 and sliding on the inner surface of the cylinder 25, and an elastic body such as rubber balls 27, 27, 27 housed in the cylinder 25 and elastically pressing the piston 26. . A screw-in type lid member 28 is attached to the other end side of the cylinder 25. This is to facilitate the removal of plaster or the like when it enters the elastic body space 29 that is substantially sealed by the piston 26. The piston 26 is made of a hard member such as plastic or metal.

FIG. 8 shows the state in which the replenishment device 16 is embedded in the plaster 14, 14, 3 is a mochi-shaped PMMA resin filled in the denture base forming space 2, and 17 is between the denture base forming space 2 and the replenishing device 16. Mochi-shaped PMMA provided
This is a reservoir for resin 3. The cake-like PMMA resin 3 filled in the denture base forming space 2 at a predetermined pressure flows through the reservoir 17 to the replenishing device 16 side and presses the piston 26 . As a result, the rubber balls 27, 2
7 and 27 are deformed into elliptical shapes, and the piston 26 moves slightly toward the inside of the cylinder 25 (to the left in the figure) by this deformation. As a result, the rice cake-like PMMA resin 3 is filled with an excess amount corresponding to the amount of movement of the piston 26, and this increased amount is filled with rubber balls 2.
Elastic force is applied toward the denture base forming space 2 at points 7, 27, and 27. However, when contraction occurs during tripolymerization and solidification of the rice cake-like PMMA resin, the rice cake-like shape is pushed out from the reservoir 17 by the piston 26.
PMMA resin 3 is replenished into the contracted portion and the deformation due to the contraction is corrected. In addition, the mochi-shaped rice cake to the replenishing device 16
Although it is difficult to confirm whether the PMMA resin 3 has been refilled, it can be determined empirically by adjusting the injection pressure of the nozzle. Furthermore, if the movable pressure of the confirmation member 1 is set higher than the resin replenishment pressure to the replenishment device 16, replenishment of the rice cake-shaped PMMA resin 3 to the replenishment device 16 can also be confirmed by the protrusion of the confirmation member 1. Can be done.

As mentioned above, the flask 4 contains the rice cake-shaped PMMA resin 3, which is sealed with the sprue hole closing valve 12 and the confirmation member 1 and maintained at a predetermined internal pressure.
5 is placed in a boiling water or steam pressure cooker while being compressed and heated at about 100℃ to 130℃ for about 10 minutes to 20 minutes.
Heat for minutes. As a result, the temperature rises from the outer walls of flasks 4 and 5 toward the inside, and a mochi-like
The PMMA resin 3 is polymerized and solidified from the peripheral portion, that is, from the buccal side of the denture base. When the density of the rice cake-like PMMA resin 3 becomes sparse due to the contraction that occurs at this time, the elasticity of the rubber balls 27, 27, 27 in the replenishing device 16 causes the rice cake-like shape of the rice cake-like resin 3 to flow through the piston 26 into the reservoir 17, as described above.
PMMA resin 3 is extruded and replenished into the sparse areas. The flasks 4 and 5 in which the PMMA resin in the sprue hole 13, air vent 10, and denture base forming space 2 have all been polymerized and solidified are divided, and the plaster is destroyed.
The denture base to which the artificial teeth 15, 15... are fixed is removed. After that, the sprue hole 13 and the air vent 1
0 PMMA resin is ground away.

<Effects of the invention> The molding material filling confirmation member in the denture base molding device according to the present invention is provided with a sprue hole closing valve in the molding material injection hole and a filling confirmation member in the air vent when press-fitting the molding material into the flask by the injection molding method. A member is provided, and the confirming member is further provided with a function as a member for preventing discharge of molding material. Therefore, it can be confirmed that the molding material injected into the flask reliably fills the denture base forming space, and at the same time, the internal pressure of the molding material in the denture base forming space can be kept at least as high as the injection pressure of the injection molding machine. It can be set and maintained equally, it can absorb the shrinkage that occurs when the molding material polymerizes and hardens, and it is possible to obtain a denture base with a shape that perfectly matches the alveolar ridge.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views showing the usage state of the molding material filling confirmation member according to the present invention, and FIG.
FIG. 4 is a perspective view showing the surface condition of one flask, FIG. 4 is a perspective view showing the sprue hole closing valve, and FIG.
Fig. 4 is a sectional view taken along the line A-A, Fig. 6 is a sectional view showing how the sprue hole closing valve is used, Fig. 7 is a sectional view of the essential parts of the replenishing device, and Fig. 8 is a sectional view showing how the device is used. FIG. 1... Confirmation member, 2... Denture base formation space, 3...
...Mochi-shaped PMMA resin, 4,5...Flask, 6...
...Front end, 7... Rear end, 8... Large diameter part, 10...
...Air vent, 12...Sprue hole closing valve, 13
...Sprue hole, 15,15...Artificial tooth, 16...
…Replenishment device.

Claims (1)

[Scope of utility model registration request] In a denture base forming apparatus that forms a denture base by injecting and press-fitting a plastic molding material into a denture base forming space formed with plaster through a sprue hole in a pair of pressed flasks, a flask at the front end of the sprue hole is used. A sprue hole closing valve provided in the part, an air vent formed of the plaster and communicating with the denture base forming space, and a molding material filling confirmation member disposed in the flask part at the final end of the air vent,
The confirmation member is formed inside the flask and includes a cylindrical front end portion facing outside of the flask, a cylindrical rear end portion facing the air vent, and a cylindrical large diameter portion located in the middle thereof. With,
The large-diameter portion slides on a cylindrical space portion slightly larger than the front and rear end portions on which the front and rear end portions slide, and the large-diameter portion has a width larger than the width of the large-diameter portion. 1. A molding material filling confirmation member in a denture base molding device, characterized in that the member is movably stored in a space consisting of a space portion.