JPH0441024B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a denture base by compression molding of a thermoplastic resin.

The present inventors previously developed a method for manufacturing a denture base by compression molding a thermoplastic resin, and filed a patent application. (Japanese Unexamined Patent Publication No. 1439/1983).

The method is to place a thermoplastic resin material on top of the plaster mold in the lower flask and heat it to soften it, then place the plaster mold in the upper flask over it and perform compression molding to produce the denture base.

The present invention relates to improvements in the above denture base manufacturing method. The objects of the present invention are to facilitate the preliminary drying of thermoplastic resin materials, to facilitate the measurement of the materials, to prevent the surface from burning when the materials are heated and softened, to uniformly soften the materials, and to shape the materials. This includes preventing major deterioration of the structure.

The present invention provides a method for manufacturing a denture base by placing a thermoplastic resin material on a plaster mold in a lower flask, heating and softening it, and then placing a plaster mold in an upper flask on top of it and performing compression molding. This method is characterized by preparing a fixed amount of thermoplastic resin material as a plurality of U-shaped plates, placing the material in multiple portions on a plaster mold in a lower flask, and heating and softening the material.

The plaster molds of the upper and lower flasks used in the present invention can be made by the known lost wax method.

The thermoplastic resin used in the present invention is prepared in a predetermined amount for one bed as a plurality of sheets, for example, 3 to 5 U-shaped plates. The shape is, for example, the first
This is similar to the dental arches shown in figures a and b. In FIG. 1a, 11 is a projection for preventing slippage. A recess into which the protrusion can fit is provided on the opposite side of the protrusion.

Examples of the types of thermoplastic resins mentioned above include:
Polystyrene, polymethyl methacrylate, polymethyl pentene-1, transparent nylon, polyethylene terephthalate, polycarbonate, polyarylate, polyester carbonate, transparent ABS
Examples include resin, polysulfone, polyethersulfone, and the like.

The method of heating and softening the thermoplastic resin material on the plaster mold in the lower flask is carried out, for example, as follows. Place the plaster mold in the preheated lower flask in a heating tank that can blow hot air from above.
On top of the mold, for example, there are 4 pieces of U made for one bed.
Two letter-shaped plates are placed and hot air is blown from above to soften the plates. Next, another board is placed on top of the previously softened material and softened with hot air. Next, another sheet is placed on top of the previously softened material and softened with hot air, completing the softening process of the resin material.

The state of this process is illustrated in FIGS. 2a to 2d.

A shows a state in which two U-shaped plates 1 are placed on top of the plaster mold 2 in the lower flask 3. b is the plaster mold 2
This shows a state in which a new plate is placed on top of the two previous plates that have softened. c shows a state in which another plate is placed on top of the previous three plates softened on the plaster mold 2. d shows a state in which a total of four plates are softened on the plaster mold 2.

In the above, we have described the case where the resin material is made into 4 boards for one bed, and the heat softening is performed in 3 times, 2 sheets, 1 sheet, and 1 sheet. The number of operations is not limited to this.

The number of boards for one bed varies depending on the size of the floor, but it is usually preferably 3 to 5 boards. Moreover, the number of times of heating and softening operation is preferably 3 to 5 times. The thickness of the plate materials is not limited to a constant thickness, but a combination of plates with different thicknesses may be used.

The means for heating and softening the resin material may be other than the hot air described above, such as infrared heating. Temperature conditions such as preheating temperature of the plaster mold, heating tank, and hot air vary depending on the type of resin material, but are usually selected from 200 to 450°C.

The resin material heated and softened on the plaster mold in the lower flask in the heating tank is then quickly conveyed to the compressor table together with the plaster mold in the lower flask.
A plaster mold in the upper flask is placed on top of this and compression molding is performed. After molding, the combined upper and lower flasks are allowed to cool or are forced to cool, and the upper and lower flasks are separated to take out the molded product.

According to the present invention, since the resin material is used in the form of a plurality of relatively thin plates, it is easy to dry the resin material, and the material can be easily measured by counting the number of plates.

In addition, since one bed of resin material is heated and softened by dividing it into multiple relatively thin plates, it is possible to prevent surface discoloration, uniform softening, and prevent large deformation of the shape during heating and softening. can do.

Examples are shown below, but the present invention is not limited thereto.

Example 1 Four plates made of polyethersulfone having the shape shown in FIG. 1a were prepared as a thermoplastic resin material. Its size is thickness h is 3mm and vertical width i is 50mm.
mm, width J is 67mm. This product was molded by injection molding. The board was dried at 180°C for 5 hours immediately before use. Place the plaster mold in the preheated lower flask in a heating tank that can blow hot air from above, and place two of the above plates on top of the mold.
The sheet was placed and heated to soften by blowing hot air at about 400°C. Next, the previous resin material is shown in Figure 2 b and c.
When the material was softened and deformed as shown in the figure, the next plate material was placed one after another and the material was heated and softened. When the four resin materials are softened and deformed as shown in Figure 2 d, they are quickly transported to the compressor table together with the plaster mold in the lower flask.
This was fitted with a plaster mold in the upper flask and compression molded. The compression pressure was approximately 70 kg/cm ² .

After compression, the combined upper and lower flasks were allowed to cool at room temperature, and after cooling to approximately 40°C, the molded product was taken out, and a good denture base molded product faithful to the mold was obtained.

[Brief explanation of the drawing]

FIGS. 1a and 1b are perspective views of a U-shaped plate made of a resin material that can be used in the present invention. Figure 2 a-d
FIG. 2 is a cross-sectional view of the plaster mold in the lower flask and the material placed on it, showing the heating and softening process of the resin material. In the figure, 1 is a resin material, 2 is a plaster mold, and 3 is a lower flask.

Claims (1)

[Claims] 1. In the method of manufacturing a denture base by placing a thermoplastic resin material on a plaster mold in a lower flask and heating it to soften it, then placing a plaster mold in an upper flask on top of it and compression molding it, a predetermined amount of heat is applied. Prepare a plastic resin material as multiple U-shaped plates,
A method characterized in that the material is placed on a plaster mold in a lower flask in multiple portions and heated and softened.