JP2550752Y2 - Dental flask - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dental flask for forming a denture by molding and processing a thermoplastic resin such as polysulfone, polyether sulfone, and polycarbonate.

[0002]

2. Description of the Related Art As a method of forming a denture by molding and processing a thermoplastic resin, there is known a method of compression-molding a thermoplastic resin having high heat resistance such as polysulfone, polyethersulfone, and polycarbonate. . In the above method, a denture is manufactured by placing a resin on a molding die, heating the resin to a softened state capable of being compression-molded, and then compression-molding the resin. However, since the mold used for manufacturing the denture is formed of gypsum, the mold contains a large amount of excess water or crystal water as plastic water when kneading the gypsum. When the water softens the resin on the mold, the water removes heat of vaporization and becomes water vapor to cool the resin. Therefore, prior to the step of softening the resin on the mold, the mold has been conventionally heated and dried.

However, the water contained in the gypsum forming the mold reaches about 20% by weight of the weight of the gypsum and a large amount of water having a large heat capacity has to be evaporated. It takes a long time and is a major factor in reducing the productivity of dentures. Further, since the flask used in the method of manufacturing a denture by molding a thermoplastic resin uses a hydraulic press having a vertical tightening mechanism, the upper and lower flasks are divided in the vertical direction. For this reason, in cases where the anterior alveolar part, which is often seen clinically, protrudes forward, when it is buried in the flask as it is, when the flask is divided up and down in the waxing process,
There is a possibility that the gypsum mold in the flask may be damaged by contact. In order to prevent this damage, when burying the model in the flask lower ring, it is necessary to put a large amount of gypsum with large heat capacity under the model and tilt the model backward to correct the undercut generated in the anterior alveolar part. is there. In this method, since a large amount of gypsum is used, it is necessary to further increase the heating and drying time of the mold, and the productivity of the denture further decreases.

[0004]

[Problems to be solved by the present invention] The present invention relates to a dental flask that can improve the heating and drying efficiency of a molding die and increase the productivity of a denture when a denture is manufactured by compression molding a thermoplastic resin. The purpose is to provide.

[0005]

The dental flask of the present invention is characterized in that the bottom of the flask is inclined. Therefore, even if the anterior alveolar part protrudes forward, there is no need to put a large amount of gypsum under the model, simply use a small amount of fixing gypsum and bury the model along the bottom of the flask. The undercut of the model can be removed only by causing the plaster-based mold to be broken by opening the upper and lower rings of the flask.

If the dental flask of the present invention is used, it is possible to make a compression mold with a small amount of gypsum, and the heat capacity of the mold in the flask can be reduced. As a result, it is possible to greatly reduce the time required for the drying and heating steps of the model, which is a major factor in the decrease in productivity when manufacturing a denture using a thermoplastic resin.

Hereinafter, an example of the dental flask of the present invention will be described with reference to the drawings. In addition, a conventional dental flask whose bottom is not inclined is illustrated. FIG. 1 is a cross-sectional view showing a state in which a gypsum model is buried in a dental flask with a tilted bottom according to the present invention. FIG. 2 is a conventional gypsum model in a dental flask with a tilted bottom. It is a cross-sectional view showing a state in which is buried. 1 and 2, 1 is a dental flask, 2 is a low-blanked plate, 3 is a model, and 4 is a burial.

If the angle of inclination of the bottom of the flask is about 5 to 30 degrees, it can be used for a wide range of cases, from general cases to cases in which the anterior alveolar portion protrudes with flavo gum or the like. A preferable inclination angle is about 5 to 20 degrees.
Further, a shape in which one end of the bottom protrudes from the upper surface of the flask is not preferable because the fixing of the model becomes unstable, and a shape in which the high side of the bottom is located 5 to 10 mm below the upper surface of the flask is preferable.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

EXAMPLE 1 As shown in FIG. 1, a standard-sized oral plaster model (120 g) having a thermocouple for temperature measurement embedded in the center of a dental flask in which the bottom of the flask lower ring was inclined at 10 degrees as shown in FIG. ) Was buried with plaster according to the usual dental practice. The cured weight of the investment material used for the investment was 130 g. After the investment material was cured, the flask was placed in a hot-air circulation dryer set at 130 ° C., and the temperature from the start of drying was measured. As a result, 40 minutes after the start of drying, the gypsum model
The temperature reached 10 ° C., and it was confirmed that water other than the water of crystallization of the gypsum model and the embedded gypsum was evaporated. Subsequently, 285 ° C
Into a hot-air circulating drier set at, and measured the temperature from the start of heating. As a result, it was confirmed that the gypsum model reached 270 ° C. which is the mold temperature of the compression molding of the sulfone resin 30 minutes after the start of heating, and that the drying and heating treatment of the gypsum model were completed in 70 minutes.

[0010]

Comparative Example 1 Except that the bottom is not inclined as shown in FIG.
A model was buried in the same manner as in Example 1 using a commercially available flask having the same shape as the flask used in Example. In order to remove the undercut of the model, a large amount of gypsum was buried under the model so that the model was inclined at about 10 degrees. The investment amount of the investment material was 200 g in total. After the investment material was cured, the flask was placed in a hot-air circulation dryer set at 130 ° C., and the temperature from the start of drying was measured in the same manner as in Example 1. As a result, it took 70 minutes to reach a temperature of 110 ° C. at which it was possible to confirm that water other than the crystal water of the gypsum model and the embedded gypsum had evaporated. Then, it put in the hot-air circulation dryer set to 285 degreeC, and measured the temperature from the heating start. As a result, 50 minutes after the start of heating, the gypsum model reached 270 ° C., which is the mold temperature of the compression molding of the sulfone resin, and it took 120 minutes to dry and heat the gypsum model.

[0011]

[Effect of the present invention] The use of the dental flask of the present invention in which the bottom of the flask is inclined makes it possible to reduce the time required for drying and heating the gypsum mold for manufacturing a denture made of a thermoplastic resin. Can greatly increase the productivity of dentures.

[0012]

[Brief description of the drawings]

FIG. 1 shows a state in which a gypsum model is buried in a dental flask of the present invention in which the bottom of the flask is inclined.

FIG. 2 shows a state in which a gypsum model is buried in a conventional dental flask in which the bottom of the flask is not inclined.

Claims (1)

(57) [Scope of request for utility model registration] 1. A dental flask wherein the bottom of the flask is inclined.