JPH0221055Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention is suitable for use in a denture base molding device, more specifically, in a device that molds a denture base by injecting a molding material into a flask using an injection molding method. The present invention relates to an injection cap 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 rice cake-like state, this was filled into the denture base forming space previously formed using plaster in a pair of flasks, 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 ~130°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. The incompatibility of the denture base with the alveolar ridge due to shrinkage has become a problem in recent years, such as poor adhesion of the denture, tooth movement, or tenderness during mastication.

<Problems to be solved by the invention> The invention realizes a mouthpiece member for a denture base molding device that prevents the molding material injected into a flask by injection molding from leaking out and maintains the internal pressure of the material. It is something to do.

<Means for solving the problem> The present invention relates to a cap member provided at the entrance of the sprue hole of the flask in order to seal the molding material injected into the flask at a predetermined pressure and maintain the internal pressure. The cap member has a different diameter portion for fixing to the flask, an injection hole formed in alignment with the central axis, a through hole that penetrates the injection hole at a substantially right angle, and is detachable from the through hole. It has a structure that can be divided into two along a plane including the central axes of the injection hole and the through hole.

<Operation> The injection hole is opened by operating the valve member,
The nozzle of the injection molding machine is applied to the nozzle member and the molding material is injected into the flask. After the injection injection is completed, the injection hole is closed by operating the valve member while the nozzle is in contact with the mouthpiece member, that is, the internal pressure of the molding material filled in the flask is maintained. Thereafter, the nozzle is separated from the base member.

<Example> Fig. 1 shows the disassembled state of the cap member 1, and 2
3 is an injection hole formed in alignment with the center axis of the main body 2; 4 is a through hole that penetrates the injection hole 3 at a substantially right angle; its diameter is as follows: It is set larger than the diameter of the injection hole 3. The cap member main body 2 has main body portions 2a and 2b in a plane including the central axes of the injection hole 3 and the through hole 4.
It is divided into two parts. Reference numeral 5 denotes a valve member made of metal or plastic that is inserted into the through hole 4, and has a hole 6 having a diameter substantially equal to the diameter of the injection hole 3 formed at a proper position of an L-shaped rod-shaped body. 7 is hole 5 and injection hole 3
This is a hole for positioning. Valve member 5
can be freely attached to and removed from the through hole 4, and the injection hole 3 is opened and closed by its rotation. Reference numeral 8 denotes a different diameter portion, for example a larger diameter portion, formed on the cap member main body 2, which fits into a groove 10 formed on the flask 9 (FIG. 2). Reference numeral 11 denotes a metal ring fitted to the nozzle abutting portion of the mouth member main body 2, which prevents the main body portions 2a and 2b from separating due to injection pressure. Reference numeral 12 denotes a circular concave portion with which the nozzle of the injection molding machine comes into contact.

In this way, the cap member 1 has main body parts 2a, 2
b, can be divided into a valve member 5 and a ring 11;
The molding material filled into the injection hole 3 during injection is easily removed.

FIG. 2 shows the surface shape of one flask 9,
Reference numeral 1 denotes the aforementioned cap member, which is fixed to the end face of the flask 9 in a state where it is fitted into a groove 10. 13 is a sprue hole, 14 is a denture base forming space, and 15 is an air vent, which is formed of plaster 16. 17, 17... are artificial teeth. The wall surface of the denture base forming space 14 matches the shape of the outer surface of the denture base. air vent 15
is a mochi-like shape at the end in the denture base formation space 14.
It is engraved at the position where PMMA resin reaches.
18, 18, . . . are mochi-shaped moieties arranged at positions facing the denture base forming space 14, particularly in areas where the denture base is likely to contract, for example, adjacent to both ends on the tongue side, with the reservoirs 19 interposed therebetween.
This is a PMMA resin replenishment device. Reference numeral 20 designates another flask that is superimposed on the flask 9, and both are clamped together with bolts or the like through screw holes 21, 21, . . . . The other flask 20 is filled with gypsum like the first flask 9, and a jaw model taken from the patient is formed using the gypsum. 22 is a confirmation member placed at the end of the flask 9. Figures 3 and 4
The figure shows a confirmation member provided at the final end of the air vent 15, which confirms the completion of filling the denture base forming space with the mochi-shaped PMMA resin 23 and confirms that the resin 23
This serves to prevent the liquid from being discharged to the outside of the flasks 9, 20. This confirmation member 22 is made up of a front end 24, a rear end 25, and a large diameter part 26 in between, and is housed so that it can move a certain distance in the left and right directions in the figure, and then End 25
faces the air vent 15, and the front end 24 faces the outside of the flasks 9, 20. Therefore, as shown in FIG. 4, when the air vent 15 is filled with the rice cake-like PMMA resin 23, the confirmation member 22 is pushed outward from the flasks 9, 20 by the pressure, and its front end 24 protrudes outside the flasks 9, 20. Stop. This protrusion confirms that the denture base forming space 14 and the air vent 15 are filled with the cake-like PMMA resin 23. At the same time, the rice cake-like PMMA resin 23
The confirmation member 22 prevents its movement. The confirmation member 22 is made of an elastic member such as rubber, and its large diameter portion 25 is brought into elastic contact with the wall surface of the inner space 27 of the flasks 9 and 20, and is supported to the extent that it does not move under its own weight or with a slight force. If you do this, you can know the filling of the molding material more reliably.

FIG. 5 shows the replenishing device 18, which is made of a hard material such as plastic or metal and has a cylinder 28 having an opening at one end.
A piston 29 is housed in the cylinder 28 and slides on the inner surface of the cylinder 28, and an elastic body such as rubber balls 30, 30, 30 is housed in the cylinder 28 and elastically presses the piston 29. . A screw-in type lid member 31 is attached to the other end side of the cylinder 28. This is to facilitate removal of plaster or the like when it enters the elastic body space 32 that is substantially sealed by the piston 29. The piston 29 is made of a hard member such as plastic or metal.

FIG. 6 shows the state in which the replenishing device 18 is embedded in the plaster 16, 16, and 23 is the denture base forming space 14.
The above-mentioned cake-like PMMA resin 19 is a reservoir of the cake-like PMMA resin 23 provided between the denture base forming space 14 and the replenishing device 18. The denture base forming space 14 is filled with a rice cake-like material with a predetermined pressure.
The PMMA resin 23 flows to the replenishing device 18 side via the reservoir 19 and presses the piston 29. As a result, the rubber balls 30, 30, 30 are deformed into elliptical shapes, and the piston 29 moves slightly toward the inside of the cylinder 28 (to the left in the figure) by the amount of this deformation. As a result, the rice cake-like PMMA resin 23 is transferred to the piston 29.
The additional amount is filled by the amount of movement, and elastic force is applied to this increased amount toward the denture base forming space 14 by the rubber balls 30, 30, 30.
However, during polymerization and solidification of the rice cake-like PMMA resin 23,
When contraction occurs, the piston 29 is removed from the reservoir 19.
The extruded mochi-shaped PMMA resin 23 is replenished into the contracted portion, and the deformation caused by the contraction is corrected.
Although it is difficult to confirm whether the rice cake-shaped PMMA resin 23 has been refilled into the replenishing device 18, it can be determined empirically by adjusting the injection pressure of the nozzle. In addition, the movable pressure of the confirmation member 22 is controlled by the replenishing device 1.
If you set it higher than the resin replenishment pressure to 8,
Due to the protrusion of the confirmation member 22, the rice cake-shaped
Replenishment of PMMA resin 23 can also be confirmed.

Next, the operation of the denture base forming apparatus having the above configuration will be explained step by step. Ring 1 on base member body 2
The cap member 1 is fixed to the overlapping surfaces of the ends of the flasks 9 and 20 in a state where the cap members 1 and 1 are fitted to prevent division of the main body. Thereafter, the flasks 9 and 20 are clamped with bolts or the like. The nozzle of the injection molding machine is brought into contact with the circular recess 12 of the mouthpiece member 1, and a mochi-shaped
PMMA resin 23 is injected. At this time, the valve member 5 is in an open state. injected rice cake
The PMMA resin 23 fills the denture base forming space 14 through the sprue hole 13, flows into the air vent 15, and presses the confirmation member 22. Furthermore, the increased internal pressure of the injected rice cake-shaped PMMA resin 23 pushes the piston 29 of the replenishing device 18, and the rice cake-shaped PMMA resin 23 is further pushed here.
PMMA resin 23 is filled. Thereafter, injection injection from the nozzle is stopped. With the nozzle in contact with the nozzle member 1, the valve member 5 is rotated approximately 90 degrees to close the injection hole 3. The cake-like PMMA resin 23 injected into the flasks 9 and 20 through these processes reliably fills the denture base forming space 14, and its internal pressure is maintained at approximately the same pressure as the injection pressure.

Next, the clamped flasks 9 and 20 are placed in boiling water or a pressure cooker to a temperature of approximately 100°C to 130°C.
Heat for about 10 to 20 minutes. As a result, the temperature increases from the outer walls of the flasks 9 and 20 toward the inside, and the cake-like PMMA resin 23 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 23 becomes sparse due to the contraction that occurs at this time, the rice cake-like PMMA resin 23 in the reservoir 19 is pushed out via the piston 29 due to the elasticity of the rubber balls 30, 30, 30 in the replenishing device 18, as described above. and replenishes the sparse area. sprue hole 13,
Air vent 15 and denture base forming space 14
Flask 9, 2 in which all PMMA resin has been polymerized and solidified
0 is divided, the plaster is destroyed, and the artificial tooth 17,1
7. The denture base with the... fixed thereon is removed. after that,
The PMMA resin in the sprue hole 13 and the air vent 15 is removed by polishing.

<Effect of the invention> The mouthpiece member of the denture base molding device according to the present invention is provided with a mouthpiece member at the entrance of the sprue hole of the flask when the molding material is injected into the flask by injection molding method, and a valve function is provided thereto. Therefore, the molding material injected into the flask does not escape to the outside, and the internal pressure of the molding material is maintained at a value approximately equal to the injection pressure. Therefore, it is possible to absorb the shrinkage that occurs during polymerization and solidification of the molding material, and to obtain a denture base with a shape that perfectly matches the alveolar ridge. Further, according to the present invention, the cap member can be divided into two main body parts and can be freely attached to and detached from the through hole into which the valve member is also inserted, so that it can be removed after the molding material has solidified. Easy to remove and clean.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view of the cap member according to the present invention, Fig. 2 is a perspective view showing the surface condition of one flask, Figs. 3 and 4 are sectional views showing the confirmation member, and Fig. 5 The figure is a sectional view of a main part of the replenishing device, and FIG. 6 is a sectional view showing the usage state of the device. 1... Cap member, 2... Cap member main body, 2a,
2b... Body portion, 3... Injection hole, 4... Through hole, 5... Valve member, 6... Hole, 8... Large diameter part,
9, 20... flask, 10... groove, 11... ring, 13... sprue hole, 14... denture base formation space, 15... air vent, 18... replenishment device,
22... Confirmation member.

Claims (1)

[Scope of utility model registration request] In a denture base forming device that forms a denture base by injecting a plasticized molding material into a denture base forming space formed of plaster in a pair of stacked flasks through a mouth member provided on an end surface of the flask,
The cap member has a different diameter portion for fixing to the flask, an injection hole formed in alignment with the central axis, a through hole penetrating the injection hole at a substantially right angle, and a removably inserted part into the through hole. What is claimed is: 1. A base member for a denture base molding device, comprising: a valve member attached to the denture base molding device;