JPH02299650A - Method and apparatus for taking out gypsum model - Google Patents

Abstract

PURPOSE:To take out a gypsum model without deforming a flask for preparing a denture by providing a notch to the contact part between the lower end of the upper tray of the flask and the upper end of the lower tray thereof after the resin piling of the gypsum model in the flask for preparing the denture and inserting an engaging piece in the notch and moving the same toward the upper or lower tray with respect to the gypsum model to take out the upper and lower trays. CONSTITUTION:A movement obstruction member 11 for obstructing the movement of an intermediate rotary body 9 in the axial direction of a cylindrical body 6 is fixed to the cylindrical body 6. An intermediate moving body having the female screw threaded with the male screw of the intermediate rotary body 9 cut in the inner surface thereof is threaded with the intermediate rotary body 9. The intermediate moving body 12 is mounted to a connection rod 14c in a movable manner. The engaging piece 15a mounted to the leading end of the connection rod 14c is engaged with a notch 15b. When a handle 10 is rotated in this state, the intermediate moving body 12 moves up and down in the axial direction of the cylindrical body and the engaging piece 15a also moves up and down with the movement of said moving body 12. Since gypsum models 3a, 3b are fixed, the upper and lower trays 2, 1 of the flask are detached by the up and down movement of the engaging piece 15a.

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to a method and apparatus for removing a plaster model for separating a plaster model from a flask for making a plaster model during denture manufacturing.

b. Prior Art The procedure for making dentures will be briefly explained with reference to FIGS. 8 to 11.

A wax denture W with an array of porcelain teeth is fixed to a model, plaster PL is placed in a lower tray F1 of a flask on which a base plate B is laid, and the wax denture W is embedded in the plaster. After the plaster P1 has hardened, the separating agent S is applied to the plaster surface, the frame of the upper tray F2 of the flask is set on the lower tray F1, and the plaster P2 is injected and the lid C is closed.
2. Solidify.

Next, this is placed in hot water to soften the wax of the wax denture W, and the flask is separated into two trays F2 and a lower tray F2. The separated flask becomes a replica model of a denture.

The recesses of this replica model are filled with resin, and the lower tray F1 and upper tray F2 of the flask are fixed with screws or a press, and the resin is polymerized. After the resin polymerization is completed, the plaster model is separated from the lower tray F1 and the upper tray F2 of the flask, and the resin-polymerized denture is taken out.

The flask usually has a shape as shown in FIG. That is, the lower tray Fl has three lower tray protrusions AI, A2.
A3, and a screw hole H1 provided in this lower tray protrusion.
1-12, 113 using the screws to connect the lid C1 upper tray F
2. The lower tray F1 is tightened (fastened) to each other. The upper tray F2 has protrusions Al, A2, A3 corresponding to the upper tray F2 so that the lower tray protrusions AI, A2, A3 and the lid C are not deformed during this fastening. Upper lid protrusions Bl, B2, and B3 are provided at the position.

Lid C can be easily removed by loosening this screw, but after resin polymerization, the lower and upper trays of the flask are firmly connected by the polymerized resin, so the plaster model can be placed under the flask. It is very difficult to remove it from the tray and upper tray.

At this time, it is common practice to separate the flask by hitting the side of the flask with a mallet. However, since flasks are usually made by casting, they are easily deformed by external forces from the side.

FIG. 12 shows an example of a flask modified in this way.

Originally, the end faces a of the lower tray and the end faces of the upper tray of the flask should match, but in this example, both end faces a and b do not match.

C3 Problems to be Solved by the Invention When the upper and lower teeth fit together during human occlusion, the cusp of the lower jaw fits into the socket between the cusp of the upper jaw and the cusp. This is considered a normal occlusion.

In order to fabricate dentures, an accurate impression is made to create a jaw model that matches the anatomical state of the oral cavity, and terminal hinge axes are created.
s) is found, the occlusal relationship is determined based on this, and wax dentures are made. Without changing this occlusal relationship, resin polymerized dentures must be made from wax dentures.

However, when using a flask that has been deformed by hitting the side of the flask with a mallet, the positional relationship between the lower and upper trays of the flask cannot be determined uniquely, and the plaster molds of the lower and upper trays are filled with resin. When the press is lowered from above and below, the supporting action of the flask frame does not work and the plaster surfaces come into direct contact, resulting in damage to the plaster model or the plaster surfaces being displaced from each other.

As a result, the following specific problems arise.

(1) When the lower and upper trays are in contact at the front and separated at the rear, or vice versa, the anterior teeth will not occlusion, resulting in oven-by I-, or early contact will occur in the anterior teeth and the molars will be affected. Poor contact occurs.

(2) When there is insufficient contact or separation between the lower tray and the upper tray on the left or right side, the occlusal position will deviate to the left or right, or early contact will occur on either side and occlusal contact will occur on the opposite side. It becomes insufficient. If the left and right deviations are extreme, there will be occlusal contact between the cusps and no occlusion.

(3) When the upper tray and lower tray are rotated and twisted relative to each other,
−〇 − The nazu arch of the arranged artificial teeth results in a crossbite. In other words, the arches of the upper and lower jaws do not oppose each other in an arched manner, but intersect.

An object of the present invention is to propose a method for separating a plaster model that allows the lower and upper trays of a flask to be removed without deforming them after resin polymerization.

d. Means for solving the problem The above problem consists of a plaster model in a lower tray with a hole in the bottom;
A resin-polymerized denture is created by filling the intermediate space of a plaster model in an upper tray with a hole in the top surface.The plaster model in a denture-making flask is removed from the denture-making flask after resin polymerization. In the model retrieval method, a notch is made in the contact area between the lower end of the upper tray and the upper end of the lower tray of the flask, and a lower surface fixing plate and an upper surface fixing plate are used in the holes of the lower tray and the hole of the upper tray to remove the inside of the flask. Fix the lower and upper surfaces of the plaster model, insert the locking piece into the above-mentioned notch, and remove the upper tray by moving the locking piece to the top side with respect to the plaster model, and remove the locking piece. A plaster model retrieval method is characterized in that the lower tray is taken out by moving the plaster model to the upper tray side, the plaster model is in the lower tray with a hole in the bottom, and the plaster model is in the upper tray with a hole in the top surface. A female screw is cut on the inner surface of the plaster model retrieval device that takes out the plaster model in the denture making flask after resin polymerization to make a resin-polymerized denture by filling the intermediate space of the plaster model with resin. a cylindrical body having a cylindrical outer surface, a lower surface fixing plate that fixes the lower surface of the plaster model in the flask from below, a frame body that connects the cylindrical body and the lower surface fixing plate, and a female screw of the cylindrical body. A bolt that meshes with the bolt, an upper fixing plate that is rotatably attached to the bolt and approaches the lower fixing plate as the bolt rotates, fixing the plaster model inside the flask from above, and the cylindrical part of the upper fixing plate. An intermediate rotary body having an inner diameter approximately equal to the outer diameter, rotatably sliding in contact with the cylindrical portion, and having a male thread cut on the outer surface, and preventing the intermediate rotor from moving in the axial direction of the cylinder. an intermediate moving body having an inner surface cut out with a female thread that is screwed into the male screw of the first intermediate rotating body; and a movement preventing member that prevents the intermediate moving body from rotating around the intermediate rotating body. a rotation prevention member, and a locking piece inserted into a notch provided at the contact portion of the lower tray and the upper tray of the denture making flask at one end, and the other end is a surface containing the axis of the intermediate rotating body. A connecting rod is rotatably fixed to the intermediate moving body within the container, and by rotating the intermediate rotating body, the connecting rod is moved up and down to remove the upper tray and the lower tray. The problem was solved by a plaster model removal device.

e. Operation Since the lower surface fixing plate and the upper surface fixing plate are connected to the frame and the cylindrical body by bolts, the upper and lower surfaces of the plaster model can be fixed by rotating the bolts.

Since the cylindrical body and the intermediate rotating body are in sliding contact, the intermediate rotating body can be freely rotated. The intermediate moving body screwed into the intermediate rotating body is prevented from rotating by the rotation blocking member, and the intermediate rotating body is prevented from moving in the axial direction by the movement blocking member. The rotation of the intermediate rotating body moves the cylindrical body in the axial direction.

The locking piece inserted into the notch provided at the contact portion of the lower tray and the upper tray is connected to the intermediate moving body via the connecting rod, and therefore moves as the intermediate moving body moves.

Only the top and bottom surfaces of the plaster model inside the flask are fixed,
Since the upper and lower trays of the flask are not fixed, the locking pieces move and the upper and lower trays are removed, and the plaster model is taken out.

f. Embodiment Hereinafter, a preferred embodiment of the plaster model retrieving device according to the present invention will be described with reference to FIGS. 1 to 7 of the drawings.

A lower tray 1 of a flask for making dentures has a hole 1a on the bottom surface and a lower tray protrusion 1b on the side surface. The lower tray protrusion 1b is the lower tray 1
are arranged at approximately equal intervals around the .

The upper tray 2 of the denture making flask has a hole 2a in its upper surface and an upper tray protrusion 2b at a position corresponding to the lower tray protrusion 2b on the side surface.

Usually, a lower plate is laid over the hole 1a of one tray 1, and an upper tray plaster model 3a is made on top of it. A denture is made by filling an intermediate space (not shown) between the second basin plaster model 3b in the upper plaster and the upper basin plaster model 3b in the upper plaster and polymerizing the resin.

After the resin has polymerized, the lower surface of the upper basin plaster model 3a is placed on the lower surface fixing plate 4. At this time, the lower end of the tray 1 needs to be above the bottom plate 5a of the frame 5 to which the fixed plate 4 is fixed.

A cylindrical body 6 is formed integrally with the frame 5 at the upper part of the frame 5. The cylindrical body 6 has a female thread cut on its inner surface and a cylindrical outer surface. A bolt 7 is screwed into the cylindrical body. An upper surface fixing plate 8 is rotatably attached to one end of the bolt.

Further, in order to rotate the bolt, a bolt rotating handle 7a is provided at the upper end of the bolt. Without turning the bolt rotating handle 9, the lower fixing plate 8 approaches the lower fixing plate 4 and fixes the Nibon plaster model 3b in the flask from above.

That is, the plaster models 3a and 3b inside the flask are clamped and fixed from both sides by the lower surface fixing plate 4 and the upper surface fixing plate 8.

An intermediate rotating body 9 having an inner diameter approximately equal to the outer diameter of the cylindrical body 6 and having a male thread cut on its outer surface is in rotatable sliding contact with the cylindrical body 6. The intermediate rotating body 9 is the intermediate rotating body 9
The handle 10 has a handle 10 for rotating the
It rotates around the cylindrical body 6 by turning. Note that since the movement prevention member 11 that prevents the intermediate rotating body 9 from moving in the axial direction of the cylinder is fixed to the cylindrical body 6,
The intermediate rotating body 9 is only capable of rotational movement.

The intermediate rotating body 9 is screwed with an intermediate moving body 12, which has a female screw cut on its inner surface to be screwed into the male screw of the intermediate rotating body 9. A rotation preventing member 13 that prevents the intermediate moving body from rotating around the intermediate rotating body is formed integrally with the intermediate moving body 12 in this embodiment, and the rotation preventing member 13 is provided on the frame 5. It meshes with the notch groove 13a. Since rotation is prevented by the rotation prevention member 13, when the intermediate rotating body rotates, the intermediate moving body 12 moves in the axial direction of the cylindrical body.

The intermediate moving body 12 has a central annular portion 12 as shown in FIG.
r and three radial rods 12a, 12b, 12c, connecting rods 14a, 1.4b are rotatably attached to the tips of the two radial rods 12a, 12b, and one radial rod A long hole 12d is provided near the tip of the rod 12c, and a connecting rod 14c is attached so as to be movable along the long hole.

Engage the locking pieces 15a at the lower ends of the two wooden connecting rods 14a and 14b with the top plate of the flask and the notch 15b in the middle of the first tray in such a way that the connecting rods 1.4a and 1.4b are almost vertical. Then, depending on the size of the denture making flask,
With the connecting rod 14c attached to the elongated hole 12d being substantially vertical, the locking piece 15a attached to the tip of the connecting rod 14c is locked into the notch 15b.

When the handle 10 is rotated in this state, the intermediate moving body 12
It moves up and down in the axial direction of the cylindrical body 6. Along with this, the locking piece 15a also moves downward by 1". Since the plaster models 13a and 13b are fixed, the second tray 2 and the first tray 1 of the flask are removed by the vertical movement of the locking piece 15a.

In other words, the plaster models 3a, 3b are taken out.

FIG. 5 shows how an incision is made in the top protrusion 2h using the toothed disc cannula 16. It is preferable that the upper surfaces of the notches 15b are horizontal and that all the upper surfaces of the notches 15b lie within one plane. Preferably, the height of the cut 15b is about 4 mm, and the depth is about 3.5 mm. Note that the depth of the notch 15b for the locking piece 15a of the connecting rod 14c attached to the elongated hole 12d is preferably about 5 mm.

As shown in FIG. 6, it is preferable that the connecting rods 14a, 14b are always urged inward by the plate springs 17. In this case, after the locking pieces 1, 5a of the connecting rods 14a, 4b are locked in the notches, the connecting rods 14. c.
The work of locking becomes easier.

The number of connecting rods 1.4a, 14b, and 14c is not limited to three, but considering workability, three is optimal.

Furthermore, since the flask is used with a wax denture embedded in plaster, it is important to take good care of the flask in order to use it for a long period of time. It is important to smooth the top of the flask and the inner metal surface of the tray with sandpaper, and then apply Vaseline after use before storing it.

g. Effects of the invention After resin polymerization, the plaster model can be taken out without deforming the denture manufacturing flask. In other words, the flask can be used semi-permanently without being deformed. Since the flask is not deformed, the first and upper trays can always be kept in the same position. As a result, it is possible to manufacture a resin polymerized denture that is completely the same shape as the denture.

Resin polymerization eliminates deformation when making resin polymer dentures, so in terms of dental technology, it is possible to reliably produce resin polymer dentures that reflect the advanced technology demonstrated when making wax dentures. .

The present invention not only has such technical advantages, but also has the economical advantage that it can be carried out with only slight modification of an existing flask and that it can be used semi-permanently.

[Brief explanation of the drawing]

FIG. 1 is a conceptual cross-sectional view of a plaster model retrieving device according to the present invention, FIG. 2 is a perspective view of the device in FIG. 1, and the third is a perspective view of the device in FIG. 1 when it is used. Fig. 4 is a top view of the frame of the device shown in Fig. 1, and Fig. 5 is a perspective view of the denture-making flask and disk canter when a notch is made in the contact area between the upper tray of the denture-making flask and the first tray. , Figure 6 is a perspective view of the upper tray projection, lower tray projection, locking piece, connecting rod, and part of the intermediate moving body when the locking piece is inserted into the notch, and Figure 7 is a partial perspective view of the intermediate moving body when the locking piece is inserted into the notch. and a top view showing only the denture making flask, No. 8
The figure is a perspective view of a flask for making dentures, and Figure 9 shows when making a plaster model in the flask for making dentures, and when resin is injected into the middle part between the plaster models and polymerized to make a resin-polymerized denture. Figures 10 and 11 are front and rear views of the flask when the upper tray and upper tray are combined, respectively, and Figure 12 is a conceptual cross-sectional view of the flask for making dentures. It is a sectional view at the boundary of the upper basin. 1...upper tray, 1a...hole, 1b...
Lower tray protrusion, 2...upper tray, 2a...hole,
2b...Upper tray protrusion, 3a...Upper tray model, 3b...Upper tray model, 4...Lower surface fixing plate,
5... Frame body, 5a... Bottom plate, 6
... Cylindrical body, 7... Bolt, 7a...
Bolt rotating handle, 8... Upper surface fixing plate, 9... Intermediate rotating body, 10... Handle, 11... Movement blocking member, 12... Intermediate moving body, 12r...
・Annular part, 12a, 12b, 12cm radial rod,
12d...Elongated hole, 13...Rotation prevention member, 13a---notch groove, 14a, 14b
+14c=connecting rod, 15a...locking piece,
15b...notch, 16...disc cutter,
17... Provisional article. Figure 9 Figure 11 1 a

Claims (2)

[Claims] (1) Inside a flask for making dentures, in which a resin-polymerized denture is made by filling the space between the plaster model in the lower tray, which has a hole in the bottom, and the plaster model in the upper tray, which has a hole in the top, with resin. In the method for removing a plaster model from a flask for making dentures after resin polymerization, a notch is made at the contact area between the lower end of the upper tray of the flask and the upper end of the lower tray, and a hole in the lower tray and a hole in the upper tray are removed. Fix the lower and upper surfaces of the plaster model in the flask using the lower fixing plate and the upper fixing plate in the hole, insert the locking piece into the above notch, and insert the locking piece against the plaster model. A method for taking out a plaster model, characterized in that the upper tray is removed by moving to the upper tray side, and the lower tray is taken out by moving the locking piece to the lower tray side. (2) Inside a denture making flask where resin is filled into the space between a plaster model in a lower tray with a hole in the bottom and a plaster model in an upper tray with a hole in the top to make a resin-polymerized denture. A gypsum model retrieval device that takes out a plaster model from a denture making flask after resin polymerization fixes a cylindrical body with a female screw cut on the inner surface and a cylindrical outer surface, and the lower surface of the plaster model in the flask from below. a lower surface fixing plate, a frame body connecting the cylindrical body and the lower surface fixing plate, a bolt that engages with the female thread of the cylindrical body, and is rotatably attached to the bolt, and when the bolt rotates, an upper surface fixing plate that approaches the direction of the lower surface fixing plate and fixes the plaster model inside the flask from the upper surface; an intermediate rotary body having a male screw cut therein; a movement prevention member that prevents the intermediate rotary body from moving in the cylindrical axial direction; and a female screw that is screwed into the male screw of the first intermediate rotary body. an intermediate moving body having a cut on its inner surface; a rotation prevention member for preventing the intermediate moving body from rotating around the intermediate rotating body; a connecting rod having one end having a locking piece inserted into the notch and the other end rotatably fixed to the intermediate moving body within a plane including the axis of the intermediate rotating body; A plaster model removing device characterized in that the upper tray and the lower tray are removed by rotating the connecting rod to move the connecting rod up and down.