阅读说明：本技术 牙科用石膏浆料 (Dental gypsum slurry ) 是由 森大三郎 吉永匡寿 小岛健嗣 渡边薰 金子司 于 2018-01-30 设计创作，主要内容包括：一种牙科用石膏浆料,包含含有半水石膏和聚羧酸盐系减水剂的牙科用石膏粉末和水,相对于牙科用石膏粉末的水的混水比为0.24～0.50,将已调拌的牙科用石膏粉末和水从调拌开始30秒后被浇注到垂直配置于平面上的内径35mm的圆筒模具中直到高度50mm,从该状态开始,该圆筒模具被以10mm/s向上方提起而扩展为平面状时,直径为141.4mm以上。(A dental gypsum slurry comprising a dental gypsum powder containing a hemihydrate gypsum and a polycarboxylate-based water reducing agent, and water, wherein the water mixing ratio of the water to the dental gypsum powder is 0.24 to 0.50, and wherein the diameter is 141.4mm or more when the kneaded dental gypsum powder and water are poured into a cylindrical mold having an inner diameter of 35mm, which is vertically arranged on a plane, from 30 seconds after the start of kneading until the height reaches 50mm, and the cylindrical mold is lifted upward at 10mm/s and expanded into a flat shape from this state.)

1. A dental gypsum slurry comprising a dental gypsum powder containing hemihydrate gypsum and a polycarboxylate-type water reducing agent, and water,

the mixing ratio of the water to the dental gypsum powder is 0.24 to 0.50,

the diameter of the kneaded dental gypsum powder is 141.4mm or more when the cylindrical mold is lifted upward at 10mm/s and expanded into a flat shape from a state in which the kneaded dental gypsum powder and water are poured into a cylindrical mold having an inner diameter of 35mm vertically arranged on a flat surface 30 seconds after the kneading is started until the height is 50 mm.

2. The dental gypsum slurry according to claim 1, wherein a mixing ratio of the water to the dental gypsum powder is 0.24 to 0.34.

3. The dental gypsum slurry according to claim 1 or 2, wherein the setting time is 4 minutes 25 seconds or less from the start of mixing.

4. The dental gypsum slurry according to claim 1 or 2, wherein the compressive strength 1 hour after the start of the mixing is 10MPa or more.

5. The dental gypsum slurry according to claim 1 or 2, wherein the spread in the diameter direction is 2% or less when the cylindrical mold is lifted up at 10mm/s from a state in which the kneaded dental gypsum powder and water are poured into a cylindrical mold having an inner diameter of 35mm and a height of 50mm, the cylindrical mold being vertically arranged on a plane, 90 seconds after the kneading.

6. The dental gypsum slurry according to claim 1 or 2, wherein the linear expansion coefficient 2 hours after the start of the mixing is 0.10 to 0.15% based on the start of the mixing.

7. The dental gypsum slurry according to claim 6, wherein the linear expansion coefficient 24 hours after the start of the mixing is 0.10 to 0.20% based on the start of the mixing.

Technical Field

The present invention relates to a dental gypsum slurry.

Background

In recent years, access diagnoses and treatment have been attracting attention as a medical modality to cope with an aging society, and the number of access diagnoses and treatment is increasing. Further, the need for visiting the clinic is expected to increase further in the future. It is considered that the opportunities for dentists to visit a clinic will increase in the dental field.

One of the operations performed in the visiting clinic in the dental field is the creation of a dental plaster model (a model for operation and a model for the lower jaw) that reproduces the state of the oral cavity of a patient. In this work, a dental impression material is used in advance to form a negative mold by taking an impression of the oral cavity of a patient. The dental gypsum slurry obtained by mixing dental gypsum powder and water is injected into the female mold and cured to obtain the aforementioned gypsum mold.

Conventionally, in a work for obtaining a dental gypsum slurry in a dental hospital or a dental laboratory, a predetermined amount of dental gypsum powder and water for mixing are collected in a container such as a rubber small-sized bowl, and the powder and water are mixed using a gypsum spatula or the like. Since many bubbles are generated during mixing, it is necessary to use a device such as an oscillator or a vacuum mixer to suppress the bubbles from being mixed into the dental gypsum slurry.

Patent document 1 listed below describes a defoaming method for a dental gypsum slurry. This defoaming method is a method of mixing a dental gypsum slurry using a defoaming device having a handle attached to a defoaming member.

Patent document 1: japanese laid-open patent publication No. H06-178926

Disclosure of Invention

However, in the visit medical care, although the mixing operation can be performed in a general household, the general household does not include a device such as an oscillator or a vacuum mixer, nor the deaerator described in patent document 1. Therefore, there is a demand for a dental plaster model in which bubbles are suppressed without using a special device such as a shaker or a vacuum stirrer.

Accordingly, an object of the present invention is to provide a gypsum slurry capable of producing a dental gypsum model with suppressed air bubbles.

In order to achieve the above object, a dental gypsum slurry according to the present invention includes a dental gypsum powder containing a hemihydrate gypsum and a polycarboxylate water reducing agent, and water, wherein a mixing water ratio of the water to the dental gypsum powder is 0.24 to 0.50, and wherein a diameter of the cylindrical mold is 141.4mm or more when the cylindrical mold is lifted upward at 10mm/s and expanded into a flat shape, from a state in which the dental gypsum powder and the water that have been mixed are poured into the cylindrical mold having an inner diameter of 35mm and a height of 50mm after 30 seconds from the start of mixing until the cylindrical mold is lifted upward at 10mm/s and the height is increased.

Conventionally, there has been no dental gypsum slurry having the above-described fluidity at the above-described water mixing ratio. Such a dental gypsum slurry also has the above-described fluidity 30 seconds after the dental gypsum powder is mixed with water. Therefore, the dental gypsum powder and water can be put into a container such as a closed bottle and shaken to stir the mixture, and a conventional dental gypsum slurry is not used, such as a gypsum spatula. Further, since the dental gypsum slurry has the above-mentioned fluidity, it is possible to suppress the mixing of air bubbles without using a device such as an oscillator when mixing or pouring the dental gypsum slurry into a female mold. According to the dental gypsum slurry of the present invention having such high fluidity and capable of suppressing the incorporation of air bubbles, a dental gypsum model with suppressed air bubbles can be produced. In the field of dental gypsum slurry, the mixing water ratio is generally defined by the mass of water relative to the mass of dental gypsum powder, and is also defined in the present application.

The mixing ratio of the water to the dental gypsum powder is preferably 0.24 to 0.34.

By setting the water mixing ratio as described above, the fluidity can be reduced early from the start of kneading, and the model deformation can be suppressed. For example, even if the female mold is inclined by an external factor or the like after the dental gypsum slurry is poured into the female mold, the dental gypsum slurry in the female mold can be prevented from flowing out of the female mold.

The curing time of the dental gypsum slurry is preferably 4 minutes 25 seconds or less from the start of mixing.

There is no known dental gypsum slurry having such a short fluidity and curing time as described above. By having such a short curing time, it is possible to shorten the time for a dentist or the like to stay at a general home when a dental plaster model is created in an interview diagnosis as described above.

The compressive strength 1 hour after the start of kneading is preferably 10MPa or more.

There is no known dental gypsum slurry having such fluidity and water mixing ratio as described above and having such compressive strength. Such a dental gypsum slurry can have sufficient mechanical strength required for dental gypsum molds.

Further, when the kneaded dental gypsum powder and water were poured 90 seconds after the kneading into a cylindrical mold having an inner diameter of 35mm and vertically arranged on a plane until the height was 50mm, and the cylindrical mold was lifted upward at 10mm/s, the spread in the radial direction was 2% or less.

By thus having low fluidity in a short time from the start of kneading, the model can be prevented from being deformed.

The linear expansion coefficient 2 hours after the start of kneading is preferably 0.10 to 0.15% based on the start of kneading, and the linear expansion coefficient 24 hours after the start of kneading is preferably 0.10 to 0.20% based on the start of kneading.

Since the coefficient of linear expansion is low as described above, a dental prosthesis can be manufactured by using a dental gypsum mold, and a dental prosthesis with a small error can be manufactured.

In summary, the present invention provides a dental gypsum slurry capable of producing a dental gypsum mold with suppressed air bubbles.

Drawings

FIG. 1 is a graph showing the results of evaluation of the fluidity of the dental gypsum slurry of the examples.

FIG. 2 is a graph showing the measurement results of the curing time of the dental gypsum slurry of the example.

Fig. 3 is a graph showing the evaluation results of the strength of the gypsum cured product after curing of the dental gypsum slurry of the example.

Fig. 4 is a graph showing the evaluation results of linear curing expansion of a gypsum cured product after curing of the dental gypsum slurry of the example.

Detailed Description

Hereinafter, the form of the dental gypsum slurry used for carrying out the present invention will be described. The following embodiments are provided for easy understanding of the present invention, and are not intended to limit the present invention. The present invention can be modified and improved according to the following embodiments without departing from the gist thereof.

The dental gypsum slurry of the present embodiment includes a dental gypsum powder containing hemihydrate gypsum and a polycarboxylate-type water reducing agent, and water.

As the hemihydrate gypsum, alpha hemihydrate gypsum, beta hemihydrate gypsum, a mixture of alpha hemihydrate gypsum and beta hemihydrate gypsum may be mentioned.

Examples of the polycarboxylate-type water reducing agent include polycarboxylate ethers, water-soluble salts of copolymers of chain olefins having 5 or 6 carbon atoms and ethylenically unsaturated carboxylic acid anhydrides, copolymers of polyethylene glycol monoallyl ethers and unsaturated dicarboxylic acids, copolymers of polyalkylene glycol mono (meth) acrylates and (meth) acrylic acid, copolymers of (meth) acrylamide having a sulfone group at the terminal thereof with acrylic acid ester and (meth) acrylic acid, copolymers of a monomer having a sulfone group such as vinyl sulfonate or aryl sulfonate or methacrylic sulfonate and (meth) acrylic acid with other monomers, copolymers of a monomer having an aromatic ring substituted with a sulfone group with maleic acid, copolymers of a monomer having a sulfone group at the terminal thereof with 4 of polyalkylene glycol mono (meth) acrylic acid ester, polyalkylene glycol mono (meth) acrylic acid ether and (meth) acrylic acid, and the like.

The content of the polycarboxylate-type water reducing agent is preferably 0.05 to 0.8 parts by mass with respect to 100 parts by mass of the hemihydrate gypsum. Further, it is more preferably 0.15 to 0.3 parts by mass, and still more preferably 0.15 to 0.25 parts by mass. When the content of the polycarboxylate water reducing agent is 0.05 parts by mass or more per 100 parts by mass of the hemihydrate gypsum, the fluidity can be further improved, and the mixing of air bubbles can be further suppressed. Further, by setting the content of the polycarboxylate water reducing agent to 0.8 parts by mass or less, the durability of the cured product after curing of the gypsum slurry can be kept good.

The dental gypsum powder according to the present embodiment preferably contains dihydrate gypsum in addition to the hemihydrate gypsum and the polycarboxylate-based water reducing agent. By containing dihydrate gypsum, the setting of the gypsum slurry can be promoted. When the dihydrate gypsum is contained, the content of the dihydrate gypsum is preferably 2 to 4 parts by mass, more preferably 2 to 3.5 parts by mass, and still more preferably 2 to 3 parts by mass, based on 100 parts by mass of the hemihydrate gypsum. When the dihydrate gypsum is contained in this manner, setting of the gypsum slurry can be further promoted by setting the content of the dihydrate gypsum to 2 parts by mass or more per 100 parts by mass of the hemihydrate gypsum. Further, by setting the content to 4 parts by mass or less, it is possible to suppress a decrease in fluidity of the gypsum slurry and also suppress swelling due to curing, and it is possible to improve the accuracy of the obtained dental gypsum model.

Examples of the dihydrate gypsum include natural gypsum and chemical gypsum. Examples of the chemical gypsum include gypsum newly synthesized from sulfuric acid and calcium carbonate, and gypsum by-produced as a by-product of various chemical processes. The average particle size of these chemical plasters is approximately 30 to 60 μm, and the dental gypsum powder of the present embodiment may contain dihydrate gypsum containing crystals having an average particle size of more than 60 μm.

The dental gypsum powder of the present embodiment preferably contains potassium sulfate. The dental gypsum powder contains potassium sulfate, and thus curing swelling can be suppressed. When the dental gypsum powder contains potassium sulfate, the content of potassium sulfate is preferably 0.5 to 3 parts by mass per 100 parts by mass of hemihydrate gypsum. Setting expansion can be further suppressed by setting the potassium sulfate content to 0.5 parts by mass or more per 100 parts by mass of the hemihydrate gypsum, and excessive setting acceleration can be suppressed by setting the potassium sulfate content to 3 parts by mass or less. The content of potassium sulfate is more preferably 0.5 to 2 parts by mass per 100 parts by mass of hemihydrate gypsum.

As described above, when the dental gypsum powder contains dihydrate gypsum, the content of potassium sulfate can be determined based on the content of dihydrate gypsum. In this case, the amount of potassium sulfate is preferably 25 to 100 parts by mass per 100 parts by mass of dihydrate gypsum from the viewpoint of obtaining curing expansion suitable for forming a dental gypsum mold.

The dental gypsum powder of the present embodiment may contain known curing retarders such as a curing expansion inhibitor such as sodium sulfate or potassium tartrate, a coloring agent, a lightweight material, a salt such as citrate, borate, or acetate, or a water-soluble polymer such as starch, gum arabic, carboxymethyl cellulose, or gelatin.

The water contained in the dental gypsum slurry of the present embodiment is 0.24 to 0.50 parts by mass per 100 parts by mass of the dental gypsum powder. Namely, the water mixing ratio of the water to the dental gypsum powder is 0.24 to 0.50. In addition, from the viewpoint of reducing fluidity early from the start of kneading and suppressing model deformation, the water mixing ratio is preferably 0.24 to 0.34. By reducing the fluidity early from the start of mixing, for example, even if the cavity die is inclined by an external factor or the like after the dental gypsum slurry is injected into the cavity die, the dental gypsum slurry in the cavity die can be prevented from flowing out from the cavity die.

Thus, the dental gypsum slurry of the present embodiment exhibits high fluidity at a predetermined water mixing ratio. Specifically, as shown in the following examples, the dental gypsum slurry of the present embodiment has a water mixing ratio of 0.24 to 0.50 with respect to water of the dental gypsum powder as described above, and has a fluidity of 141.4mm or more in diameter when the dental gypsum powder and water are poured into a cylindrical mold having an inner diameter of 35mm vertically arranged on a plane until the height is 50mm 30 seconds after the start of mixing, and the cylindrical mold is lifted upward at 10mm/s and expanded into a plane.

Since the dental gypsum slurry of the present embodiment has high fluidity as described above, it can be prepared by filling dental gypsum powder and water into a container such as a bottle, sealing the container, and shaking the container.

The container used for mixing the dental gypsum slurry of the present embodiment is, for example, a bottle-shaped container, and includes a bottomed cylindrical container body having an opening and a lid. The lid can close the opening of the container body and seal the space inside the container.

Here, the sealing means airtightness to the extent that the dental gypsum powder and water do not leak to the outside when the container is shaken after the opening of the container is closed with a lid. As long as such a sealing can be achieved, the shape of the cap, the method of fixing the cap to the container body, and the like are not particularly limited.

The inner diameter of the opening of the container is not particularly limited as long as dental gypsum powder and water can be filled in the opening and dental gypsum slurry can be poured out, and is, for example, 1cm to 20 cm.

The capacity of the container is not particularly limited, and is preferably 0.01L to 1L, considering, for example, the required amount for 1 visit of the dental gypsum slurry at the time of medical examination.

Further, it is preferable that at least a part of the container is transparent or translucent to make the inside visually recognizable.