JPH0698155B2 - Dental heat-expandable separating agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention was devised in the field of dental technology so as to compensate for polymerization shrinkage when polymerizing a denture base resin, for example, and to finish it into a shape that fits the inner wall of the oral cavity. The present invention relates to a heat-expandable separating agent.

Examples of the procedure for creating a denture base using a resin include, for example, “Skinner Dental Science” (Medical and Dental Publishing Co., Ltd., issued October 31, 1974), pages 175 to 176, and “Dental Science and Technology”. Academic practice guidelines "(Ito Dental Publishing Co., Ltd., Showa 51)
(Published February 25, 2013) As shown on pages 33-40, etc., the following method is usually adopted.

That is, first, a precise impression of the prosthesis site in the patient's mouth is taken, and a sub-membrane type is made by pouring plaster, then a prosthesis is made on this plaster membrane type with floor wax and reproduced with an articulator etc. After confirming the properties, it is embedded in a polymerization flask. Then, after the investment material is solidified, the previously molded floor wax is melted and flowed out in an electric furnace or the like to form a cavity, and a separating agent is applied to the surface of the cavity, and a methacrylate-based floor resin or the like is applied to the cavity. The material is filled in the form of a paste or a slurry and heat-polymerized in hot water to obtain a resin denture base.

It is well known that a floor resin such as a methacrylate resin undergoes polymerization shrinkage during this polymerization process, and this polymerization shrinkage cannot be eliminated. Therefore, even if the cavity is precisely formed by the procedure as described above, a void is formed between the cured resin and the inner wall of the cavity due to the polymerization shrinkage, and the precision of the molding surface is reduced, and the denture base is fitted to the inner wall of the oral cavity. Will not be obtained.

The present invention has been made in view of such problems, and by devising a separating agent, it compensates for polymerization shrinkage at the time of heat polymerization molding of a dental resin, and the precisely molded cavity An object of the present invention is to provide a dental separating agent capable of reliably adding a polymerization-curable resin to the inner wall and giving a dental resin molded product fitted to the inner wall of the oral cavity.

And such an object can be easily achieved by sharing a foaming agent that foams by heating in the separating agent. That is, when the heat-expandable separating agent is applied to a proper place of the cavity and the dental resin is heat-polymerized, the resin at the time of polymerization and curing is foamed (expanding) of the separating agent so that the resin on the opposite side is void. Pressed against the inner wall, the cured resin adheres to the inner wall of the cavity, which is a precise transfer of the impression of the oral cavity. As a result, it is possible to obtain a resin formed body that surely fits the inner wall of the oral cavity.

The dental separating agent is used for the purpose of improving the separation between the surface of the investment material gypsum and the polymerization-cured resin molded body, and smoothing the surface of the resin molded body. The main component of the separating agent is water as a solvent, and a water-soluble thickening agent such as sodium alginate, poval, CMC, polyvinylpyrrolidone, etc., as an adhesive, and a coloring agent for identification, etc. are blended if necessary. . Also,
A surfactant may be added to improve the dissolution of the solute.

The separating agent of the present invention imparts thermal expansivity to the conventional separating agent as described above by containing a foaming agent that foams by heating, and thereby, in addition to the original function of promoting mold release as a separating agent. The feature is that it has a shaping function by heat expansion.

As the foaming agent used in the present invention, for example, a microencapsulated foaming agent (trade name: Matsumoto Microspheres, etc.) is preferable, and by adding an appropriate amount of such a swelling agent to the separating agent, It is possible to impart heat expandability.

Then, in performing the molding of a dental resin using this heat-expandable separating agent, in the same manner as described in the above-mentioned prior art, taking a precise impression in the oral cavity, making a sub-membrane type with gypsum, The creation of a prosthesis with a floor wax on a gypsum membrane mold, confirmation of reproducibility, embedding in a polymerization flask, solidification of investment material, formation of cavities by melting and outflow of floor wax, etc. are performed in sequence.

Then, while a normal separating agent is applied to the oral impression transfer surface side in the cavity, the above-mentioned heat-expandable separating agent is applied to the surface on the opposite side, and then the same procedure as above is applied to the cavity. Filling of the resin material and heat polymerization may be sequentially carried out.

Then, the expandable separating agent applied to the side opposite to the intraoral impression transfer surface of the cavity foams and expands by heating, and the resin is polymerized and cured while being pressed against the intraoral impression transfer surface side in the cavity. Become. As a result, the cured resin comes into close contact with the intraoral impression transfer surface to be shaped in spite of polymerization shrinkage, and a resin molded product that accurately fits the inner wall of the oral cavity can be obtained.

FIG. 1 is a schematic diagram for explaining the effect of the above heat-expandable separating agent. The ordinary separating agent A is applied to the intraoral impression transfer surface 1a in the cavity 1 formed by melting and flowing out of the wax by the above-mentioned procedure. Then, the heat-expandable separating agent B is applied to the opposite surface 1b. Next, when a paste or slurry resin material C is filled into the cavity 1 and polymerized by heating,
As shown in FIG. 2, the resin is cured while being pressed against the intraoral impression transfer surface 1a by the thermal expansion of the decomposing agent B, and the intraoral impression transfer surface 1a is accurately transferred to the molding surface of the resin. It

At this time, a gap is formed between the surface 1b coated with the separating agent B and the cured resin due to polymerization shrinkage of the resin and expansion of the separating agent B, but this surface is not a portion in contact with the inner wall of the oral cavity. As a resin molded body, no trouble occurs.

Example A thin plate having the following configuration (A), (B), and (C) was prepared, and each thin plate was heated in an oil bath to examine the volume change rate.

(A) Sodium alginate 5% aqueous solution 4 g and calcium sulfate
A 10 ^mm × 20 ^mm × 0.4 ^mm thin plate formed by kneading 1 g and molding it into a sheet (Comparative Example).

(B) A thin plate of the same size formed into a sheet by mixing 17% by weight of a microencapsulated foaming agent (Matsumoto Microsphere) with the constituent material of (A) (Example).

(C) A thin plate of the same size formed into a sheet by mixing 67% by weight of the microencapsulated foaming agent (same as above) with the constituent material of (A) above (Example).

The results are as follows, and the thin plates (B) and (C) of the examples
Indicates a higher coefficient of volume expansion than the thin plate (B) of the comparative example.

Example A heat-expandable separating agent having the following composition was prepared, and this separating agent was applied to the opposite side 1b of the impression transfer surface 1a of the molding cavity 1 as shown in FIG. Is a non-thermally expandable separating agent having the same composition except that the foaming agent is not mixed in the above-mentioned composition, and then a paste-type methacrylate floor resin is filled in the cavity 1 and heated in hot water. It was heated and polymerized.

As a result, the resin is pressed against the impression transfer surface 1a by the thermal expansion of the expansive separating agent during polymerization and curing,
A resin molded body to which 1a was accurately transferred was obtained.

(Composition) Sodium alginate 2% by weight Polyvinylpyrrolidone 1.5% by weight Foaming agent (Matsumoto Microspheres) 20% by weight Food Red No. 102 0.001% by weight Water remaining total 100% by weight

[Brief description of drawings]

1 and 2 are explanatory views illustrating a method for molding a dental resin molded body using the heat-expandable separating agent of the present invention. 1: Cavity 1a: Imprint transfer surface 1b: Opposite surface A: Heat-expandable separating agent B: Non-heat-expandable separating agent (normal separating agent) C: Resin (material)

Claims (1)

[Claims] 1. A heat-expandable dental separating agent containing a foaming agent that foams when heated.