JPS58165838A - Fabrication of dental prosthesis made of resin - 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 resin dental prosthesis.

Conventional manufacturing methods of this type include placing a model of the dental prosthesis, a sprue, and an ejection gate made of a material that can be melted and flowed out, such as wax, in a pressure flask, then immersing them in plaster, and after the plaster hardens, the dental prosthesis model is placed in a pressure flask. A plaster mold surrounding the dental prosthesis-shaped cavity is created by melting and pouring out the material, then heat-softened synthetic resin is injected and press-fitted through the sprue hole, and after the resin has cooled and hardened, a pressure flask is opened and the plaster mold is crushed. A resin dental prosthesis is obtained.

However, when injecting resin into this type of plaster mold, the injection pressure is limited because the plaster mold is weak in strength, and it is extremely difficult to set various injection conditions. In order to solve this problem, conventional methods used computers to control injection conditions according to changes in the internal pressure of the plaster mold, which required extremely expensive equipment.

Therefore, the present invention provides a manufacturing method that makes it possible to control the internal pressure of a plaster mold and at the same time perform good shrinkage correction without using such expensive equipment, thereby manufacturing a high-precision resin dental prosthesis at a low cost. The purpose is to make it possible.

That is, the feature of the present invention is that thermoplastic resin softened by heat is injected and press-fitted into a plaster mold surrounding a prosthesis-shaped cavity;
In the manufacturing method of a resin dental prosthesis, in which the dental prosthesis is obtained by crushing the plaster mold after the resin has cooled and hardened, the resin reservoir is connected to the resin injection port through a sprue, and the prosthesis shape is communicated with the resin reservoir through a runner. A cavity and a pressure relief chamber communicated with the cavity through an air vent are provided, and after the softened resin injected from the resin injection port is sequentially filled, the resin reservoir and the pressure relief chamber are connected to the prosthesis. The resin inside the mold cavity and the pressure relief chamber compensate for shrinkage, and the internal pressure of the plaster mold is adjusted by the pressure relief action.Furthermore, heaters are installed in the resin reservoir chamber and the pressure relief chamber. The reason is that the injection of this product has enhanced the effect of correcting contraction.

Next, embodiments based on the features of the present invention will be described with reference to the accompanying drawings.

/ is a pressure flask that stores a plaster mold λ.

3 is a dental prosthesis-shaped cavity formed in the plaster mold λ,
The runner hole and the discharge gate hole S are in communication.

B is a resin reservoir chamber which communicates with the runner hole 7, and communicates with the resin injection port g via the sprue hole 7.

wo is a pressure relief chamber communicating with the discharge date 1 hole S, and the screw 9a
A piston 9C pressed by a bullet 9b whose pressing force can be adjusted is housed, and a resin extraction hole qd is provided on the side.

Although not shown, an electric heater is provided around the pressure relief chamber and the resin reservoir chamber.

Furthermore, the case where the sprue hole and the reservoir chamber A are formed of plaster and the sprue hole and the reservoir chamber B are made of metal is illustrated, but as shown in FIG.
may be stored in a plaster mold.

// is an artificial tooth made of resin.

When the high-strength synthetic resin that has been softened by heating is injected and press-fitted from the resin injection port g, the softened synthetic resin flows into the reservoir chamber B through the sprue hole and fills it, and then is injected into the cavity 3 through the runner hole. After filling the cavity 3, it is injected into the pressure relief chamber through the discharge gate hole S to fill it.

Further, when injection press-fits, resin is injected into the pressure relief chamber 9 while retracting the piston 9C, but when the internal pressure of the plaster mold reaches a predetermined pressure, the resin is discharged from the extraction hole 9d to suppress the internal pressure of the plaster mold. As a result, the resin will surely spread to every corner of the cavity 3.

Thereafter, as the resin cools and hardens and shrinks, the resin in the pressure relief chamber 9 and the resin in the reservoir chamber 6 are injected into the cavity 3 by the pressing force of the piston 9C and the holding pressure of the injection molding machine, thereby reliably correcting the shrinkage. In this case, since the pressure relief chamber 9 and the reservoir chamber B are heated, the contraction correction can be performed even better.

In addition, a heater may be stored in the stone △ blue and white as a heating means for the reservoir chamber B, or a heater rod may be inserted into the sprue hole 7. Further, the structure of the pressure relief chamber may be changed as appropriate.

The internal pressure of the resin injected and press-fitted in this way is suppressed by the reservoir chamber A and the pressure relief chamber 9, and shrinkage correction can be effectively performed, so that there is no need to use an expensive control device such as a computer. A highly accurate resin dental prosthesis can be obtained with high efficiency.

The effects are great, such as making it possible to perform resin injection molding by setting the injection injection amount.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention; FIG. 1 is a sectional view, FIG. 2 is a sectional view of a pressure relief chamber, and FIG. 3 is a sectional view of a metal sprue. Ko00 plaster mold 30. Dental prosthesis shape, one runner hole 3. , discharge gate hole Otsu9. Resin reservoir chamber 71. Sprue hole g1. Injection port 9, pressure relief chamber 1

Claims (1)

[Claims] A method for manufacturing a resin dental prosthesis, in which a heated and softened thermoplastic resin is injected and press-fitted into a plaster mold surrounding a prosthesis-shaped cavity, and after the resin cools and hardens, the plaster mold is crushed to obtain a dental prosthesis. In the resin injection process, a resin reservoir is provided which communicates with the resin injection port through a sprue, a prosthesis cavity which communicates with the resin reservoir through a runner, and a pressure relief chamber which communicates with the cavity through an air vent. A method for manufacturing a resin dental prosthesis, characterized in that the internal pressure of the heated and softened resin injected through the mouth is adjusted by the resin reservoir, the prosthesis cavity, and a gypsum mold.