JPH0669460B2 - Molding method for thermoplastic resin denture base - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing an excellent denture base by a compression molding method using a thermoplastic resin.

[Prior Art] As a method for producing a denture base made of a thermoplastic resin by a compression molding method, as described in JP-A-58-1439, a heat-melted resin is put in a gypsum-based mold. After that, a method of compression molding is known.

In addition, as a method for simplifying the operation, a method is used in which a thermoplastic resin is injection-molded into a preform (preform), the preform is heated and softened on a molding die, and then compression-molded (JP-A-60-114252). Japanese Patent Laid-Open Publication No. 61-125339).

[Problems to be Solved by the Invention] However, in the method described in JP-A-58-1439, there are drawbacks that the operation is complicated and defects are likely to occur in the molded denture base.

Further, JP-A-60-11452 or JP-A-61-212533
According to the method described in Japanese Patent Publication No. 9, the heating and softening of the preform is immediately performed by hot air or a far infrared heater and molded, but when the preform is softened only by heating with hot air, it is artificially compressed. If the preform is softened until the resin can sufficiently enter between the teeth, the preform loses its shape, and the resin amount in the alveolar part, which requires the most resin amount, tends to be insufficient. .

Also, when softening the preform with a far infrared heater,
There are many cases that require a large amount of resin, and when preforms are stacked and used, if you try to soften the resin at once, the preform below will not soften,
Alternatively, the above preform may be deformed or burnt. Therefore, the method disclosed in JP-A-60-114252 employs an extremely troublesome method of softening the preform in a plurality of times.

[Means for Solving the Problems] Therefore, the present inventor has diligently studied a method for forming a denture base made of a thermoplastic resin in a simple and reliable manner by solving the drawbacks of the above-mentioned conventional methods, and as a result, preheating of the preform has been performed. After performing the above, it was found that a thermoplastic resin denture base can be molded easily and surely in any case by heating and softening the preform with a far infrared heater and performing compression molding, and arrived at the present invention. did.

That is, according to the present invention, in producing a thermoplastic resin denture base, a thermoplastic resin preform is placed on a molding die, and the temperature is not less than the thermal deformation point of the thermoplastic resin and not more than the melting point. There is provided a method for molding a denture base made of a thermoplastic resin, characterized in that the preform is preheated, then the preform is heated and softened by a far-infrared heater, and then the upper and lower molding dies are pressed against each other.

Hereinafter, the present invention will be described in detail.

First, a thermoplastic resin preform is set on the model of the lower flask, and the preform is preheated at a temperature not lower than the thermal deformation point and not higher than the melting point to deform it into a shape conforming to the model.
At this time, a plurality of preforms that are stacked together are integrated.

Next, the preform thus preheated is heated and softened by a far infrared heater. Then, while maintaining the required resin thickness of the preform, the upper resin of the preform is softened to a viscosity that can be sufficiently inserted between the artificial teeth by compression molding, while the resin of the lower part is moved by the compression molding. It softens to the point where it happens. Subsequently, by pressing the upper flask holding the artificial tooth under pressure, a good denture base made of thermoplastic resin can be formed.

The hot air heating method is suitable as the preheating method,
A method using a far infrared heater or the like is also possible.

The molding method of the present invention is particularly effective for a resin having a high melting point, such as a polysulfone, a polyether sulfone, a polycarbonate, etc., which makes it difficult to obtain a thick preform by injection molding.

[Examples] Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples.

(Example 1) A plaster mold for molding a denture base was prepared according to a standard dental method. After drying the lower gypsum mold at 270 ℃, the thickness is 6mm.
Two polysulfone preforms were set on a gypsum-shaped model and preheated at 270 ° C. for 5 to 10 minutes. Next, the far-infrared heater was used to soften the preform, and the upper and lower gypsum molds were pressed against each other to produce a lower denture.

As a result, an excellent mandibular complete denture without defects was obtained even in the case where a large amount of resin was required.

(Comparative Example 1) As in Example 1, two polysulfone preforms having a thickness of 6 mm were set on a lower gypsum model, and the preform was softened with hot air at 380 ° C for 5 minutes to form upper and lower gypsum models. The lower jaw complete denture was manufactured by pressing.

As a result, the preform was deformed during softening, and defects were observed in the manufactured denture base, which is thought to be due to lack of resin.

Comparative Example 2 Example 1 except that the preform was not preheated.
A mandibular complete denture was manufactured in the same manner as in.

As a result, the preform was deformed due to the residual stress during the preform injection molding during softening, and the manufactured denture base was found to be defective due to lack of resin. Further, burning of the resin was recognized.

[Effects of the Invention] As described above, according to the method for molding a thermoplastic resin denture base of the present invention, far infrared rays are obtained after preheating the preform at a temperature not lower than the thermal deformation point of the thermoplastic resin and not higher than the melting point. Since it is heated and softened by, and then compression molded, there is no deformation of the preform or surface burning, and a good denture base can be easily and surely obtained for a wide range of cases.

Further, the molding method of the present invention is extremely excellent in that it is effective for high melting point resins such as polysulfone, polyether sulfone, and polycarbonate, which are difficult to obtain a thick preform by injection molding.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuya Sakamoto 3-10 Nakamiyakitamachi, Hirakata-shi, Osaka Ube Industries Ltd. Hirakata Laboratory (56) References JP-A-61-209652 (JP, A)

Claims (1)

[Claims] 1. When manufacturing a denture base made of thermoplastic resin,
Placing the thermoplastic resin preform on the mold, pre-heating the preform at a temperature not lower than the thermal deformation point of the thermoplastic resin and not higher than the melting point, and then heat and soften the preform with a far infrared heater, Next, a method for molding a denture base made of a thermoplastic resin, characterized by pressing the upper and lower molds together.