JPS60232144A - Fabrication of denture bed - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

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 Patent Application Laid-Open No. 1489/1989).

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 containing the artificial tooth on top of it and perform compression molding to create the denture base. This is the way to do it.

As a result of research, the present inventors found that in the above compression molding method,
When no treatment is applied to the upper flask or the artificial tooth built into the upper flask, as in the case of commonly used compression molding, the fusion between the artificial tooth and the resin forming the denture base is insufficient. However, it was found that the artificial tooth had the disadvantage that it was easy to detach from the denture base.

The object of the present invention is to provide a method that improves the above-mentioned drawbacks and provides good results, ie, a denture base in which the artificial tooth is firmly implanted and has good filling properties.

A feature of the present invention is that a thermoplastic resin material is placed on top of the plaster mold in the lower flask, heated and softened, and then the plaster mold in the upper flask containing artificial teeth is placed on top of it and compressed. The method of manufacturing a denture base by molding involves preheating a portion of the artificial tooth to 80 to 800°C.

The thermoplastic resin used for denture bases in the present invention does not undergo thermal deterioration through the molding method, has an appropriate viscosity, has good formability, and has a color similar to that of the gums. It is required that the resin be colorable, have appropriate rigidity and moisture resistance, and be tough enough not to cause stress cracks during use. Therefore, polystyrene, polymethyl methacrylate, polymethyl pentene-1, transparent nylon, polycarbonate, polyarylate, polyester carbonate, polyethylene terephthalate, transparent AB8, polysulfone resins, etc. are used, but in particular polysulfones such as polysulfone and polyethersulfone are used. This type of resin is preferable because it has excellent moisture resistance, rigidity, stress cracking resistance, etc.

The polysulfone resin used as a preferred embodiment in the present invention is defined as a polyarylene polyether polysulfone in which arylene units are located in a disordered or ordered manner with ether and sulfone bonds. Examples include polysulfone Udel manufactured by UCC and polyether sulfone Viatre manufactured by @, which have a structure of H3.

The artificial teeth used in the present invention include resin teeth made of acrylic resin, porcelain teeth, polycarbonate teeth, polyarylate teeth, polysulfone teeth, etc., which are commonly used as artificial teeth in the past.

As a material for artificial teeth, it is a resin that can be colored to resemble natural teeth, has appropriate rigidity, wear resistance, and moisture resistance, and is tough enough to prevent stress cracks during use. something is required.

Therefore, in addition to the above-mentioned artificial teeth, artificial teeth made of polystyrene, polymethylpentene-1, polyamide, polyester carbonate, polyethylene terephthalate, transparent ABS, polyether sulfone, etc., and compositions containing these resins and appropriate reinforcing agents are used. Artificial teeth are available. It is preferable to use an artificial tooth made of a material having the same or similar structure or properties as the thermoplastic resin for denture bases, since the adhesion between the artificial teeth and the denture base is better.

The method of incorporating the artificial tooth into the plaster mold in the upper flask is not particularly limited.

The method is commonly practiced: a wax model of the denture base containing the artificial teeth is placed in a flask, and plaster is poured in and allowed to harden.

After the gypsum hardens, a method is applied in which the wax is heated and softened by a proper method and then flowed out.

Any method can be used to preheat the root of the artificial tooth built into the flask, such as heating only a predetermined part of the artificial tooth locally with hot air or infrared rays, or heating with a burner. be. If only the part to be implanted into the denture base, that is, the root of the artificial tooth, is heated to a state close to softening, and the tip of the artificial tooth is compression molded without changing its shape, the relationship between the artificial tooth and the denture base will be better. A method that locally heats only the root of the artificial tooth is applied to obtain a good-looking corrugated tooth (a combination of an artificial tooth and a denture base) with good adhesion and no change in the shape of the artificial tooth. .

The root of the artificial tooth needs to be preheated at a temperature of 80 to 800°C. If the temperature is less than 80°C, the preheating effect will be poor and the adhesion between the artificial tooth and the denture base will be insufficient. Also 800°C
If the temperature exceeds this, the artificial tooth may become soft and deformed, or thermal deterioration may occur.
This is undesirable because the strength of the artificial tooth is significantly reduced due to residual strain caused by heat. Furthermore, a temperature of 100 to 270°C is preferable because there is no change in the shape or strength of the artificial tooth and higher adhesion to the denture base can be obtained.

Hereinafter, the present invention will be specifically explained with reference to examples, but these are merely illustrative of preferred embodiments and are not limited to the scope of the examples.

Example 1 (200F as described in Japanese Industrial Standard JI8T-6511)
The artificial tooth 1 formed from the above is implanted in a paraffin wax model so that the line connecting the incisal end 1' and the tooth neck 1'' forms an angle of 45° with the paraffin wax model, and after being embedded in plaster, the artificial tooth 1 is cast with wax and made into a plaster mold. was formed.

Divide the plaster mold into two parts, an upper part (the one containing the artificial tooth) and a lower part, and place a plate-shaped molded product of polyether sulfone colored to resemble gums on top of the plaster mold in the lower flask.
It was softened by blowing hot air at 80°C for 5 minutes.

Next, hot air at 220° C. was applied to the root of the artificial tooth made of polyether sulfone in the upper flask for 2 minutes to preheat it, and then the upper and lower flasks were brought together and compression molded, followed by natural cooling.

After cooling, the upper and lower flasks were divided, and the molded product for the artificial tooth fracture test was taken out.

As shown in FIG. 1, the resin bed part 2 is fixed with a holder 8, and the other artificial gear end part 1' is fixed with a predetermined metal fitting 4 at a load speed of 12.
The fracture strength at t0 when the fracture test was carried out at f/min was 28 kqf, which was a sufficiently high value to cause no practical problems.

Comparative Example 1 An artificial tooth made of polyethersulfone was molded under the same conditions as Example 1 without preheating,
An artificial tooth fracture test was conducted.

The fracture strength was not 'rklif L, and only showed a low value that would pose a practical problem.

Comparative Example 2 Everything was the same as Example 1 except that the artificial tooth formed with polyether sulfone was preheated by blowing hot air at 880°C for 2 minutes.
When molding was performed under the same conditions as above, the artificial tooth was greatly deformed and a good molded product could not be obtained.

Example 2 [Yes] A flask in which a wax model of a denture base in which an artificial tooth formed from poly+ruho:z (UOO9lUdel P1700) was implanted was heated to soften and flow the wax, and then a mixture of polysulfone and A U-shaped molded product colored like gum was placed on the plaster mold in the lower flask and heated to 850°C.
The molded article was softened by blowing hot air.

Then, after preheating the root of the artificial tooth made of polysulfone in the upper flask by blowing hot air at 190° C. for 2 minutes, the upper and lower flasks were brought together and compression molded, and then allowed to cool naturally.

After cooling, the upper and lower flasks were separated and the denture base was taken out.

Comparative Example 3 A denture base in which the artificial tooth was firmly planted without easily coming off even when the artificial tooth was strongly pressed was obtained. An artificial tooth made of polysulfone was molded under the same conditions as in Example 2 without preheating. Then, a denture base was molded, but the artificial tooth came off from the denture base with just a slight push.

, 4. Brief Description of the Drawings FIG. 1 is a side view showing an embodiment of the artificial tooth fracture test.

l......Artificial tooth 1'...Incisal end 1'' of artificial tooth...
...Cervical part 2 of artificial tooth ...Resin base part 8 ...... Holder 4 ...... Artificial tooth tension fitting Fig. 1

Claims (1)

[Claims] A method of manufacturing a denture base by placing a thermoplastic resin material on top of the plaster mold in the lower flask and heating it to soften it, then placing the plaster mold in the upper flask containing the artificial tooth on top of it and performing compression molding. , the root of the artificial tooth is 8
A method characterized by preheating to 0 to 800°C.