JP6853072B2 - Base material for dental impression material and dental impression material - Google Patents

Description

The present disclosure relates to a base material for dental impression material and a dental impression material containing the same.

Conventionally, as a dental impression material, a hydrocolloid impression material (for example, an agar-based or alginate-based impression material) is widely used. For example, an alginate-based impression material is usually prepared by kneading a paste-like base material containing alginate and a paste-like curing material containing a curing agent with an automixer. The impression material is required to have an appropriate consistency and the time required for impression collection (that is, the curing time) is adjusted to an appropriate range. Those in which the base material and the curing material are in the form of a paste have better operability and reproducibility than those in the form of powder, for example.

Patent Document 1 describes dental alginic acid in which two types of pastes, a main material paste containing alginate, water and a filler as main components, and a curing material paste containing calcium sulfate and liquid components as main components are mixed and cured. In the salt impression material composition, one or more selected from color ginan, purulan, guard run, xanthan gum, gellan gum, pectin, konjak glucomannan, xyloglucan, guar gum, arabic gum, locust bean gum in the main material paste. Described is a dental alginate impression material composition characterized by containing 0.01 to 15% by weight of saccharides and 0.5 to 50% by weight of polybutene in the curing material paste.

Patent Document 2 describes an alginic acid-containing aqueous composition containing (A) alginic acid or a derivative thereof, (B) water, and (C) a non-reducing sugar.

Patent Document 3 contains an alginate, a gelling reaction agent, and a non-reducing sugar, and the non-reducing sugar is in the range of 1 part by mass to 20 parts by mass with respect to 1 part by mass of the alginate. Describe the dental alginate impression material, which is characterized by being contained in.

Patent Document 4 describes (A) calcium sulfate, (B) a salt of a metal having a solubility in water at 20 ° C. of 0.1 to 1.5 g / L and an ionization tendency smaller than calcium, and (C) alginate. Described are dental alginate impression materials characterized by containing calcium sulphate.

Japanese Unexamined Patent Publication No. 2002-087922 Japanese Unexamined Patent Publication No. 2011-225507 Japanese Unexamined Patent Publication No. 2012-106937 Japanese Unexamined Patent Publication No. 2014-156437

The base material for dental impression material usually has a high viscosity to some extent, but when a high shear rate of shearing force is applied to the base material for dental impression material during manufacturing or kneading with a curing material, high stress is generated. It was not preferable from the viewpoint of handleability.

One aspect of the present invention solves the above-mentioned problems, has good impression accuracy in the dental impression material, and has good handleability when the base material for the dental impression material and the curing material are kneaded and when the dental impression material is used. It is an object of the present invention to provide a base material for a dental impression material capable of giving, and a dental impression material containing the same.

One aspect of the present invention is a base material for dental impression material containing water, alginate, and a filler.
The filler contains diatomaceous earth and silica particles.
Provided is a base material for dental impression material, wherein the mass ratio of the diatomaceous earth and the silica particles in the base material for dental impression material is 4/1 to 1/1.

One aspect of the present invention provides a dental impression material containing a base material for dental impression material and a curing material according to one aspect of the present invention.

According to one aspect of the present invention, it is possible to provide good impression accuracy in the dental impression material and good handleability when the base material for the dental impression material and the curing material are kneaded and when the dental impression material is used. A possible base material for dental impression material and a dental impression material containing the same are provided.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these aspects.

<Base material for dental impression material>
One aspect of the present disclosure provides a base material for dental impression material (sometimes referred to as a "base material" in the present disclosure) containing water, alginate, and a filler. The substrate of the present disclosure is used as a substrate of an alginate-based dental impression material. In the substrates of the present disclosure, the filler comprises diatomaceous earth and silica particles. The base material for dental impression material of the present disclosure has a high shear stress under a low shear rate due to its specific composition, particularly the combination of diatomaceous earth and silica particles. Gives good handleability at the time of manufacturing (that is, when the base material and the curing material are kneaded) and at the time of use (that is, when taking an impression). Further, by having a small shear stress under a high shear rate, good handleability is provided at the time of manufacturing the base material and at the time of kneading the base material and the cured material.

In the present disclosure, "diatomaceous earth" refers to soil produced by the deposition and fossilization of diatom shells. In a typical embodiment, diatomaceous earth is a particle. The diatomaceous earth may be a commercially available product. Commercially available products are supplied by, for example, EP Minerals LLC., Imerys Filtration Inc., Chuo Silica Co., Ltd. and the like. The base material for dental impression material of the present disclosure contains diatomaceous earth and thus has a relatively low permanent strain required as a dental impression material, thereby giving good impression accuracy.

In a preferred embodiment, the average particle size of diatomaceous soil as measured from an electron microscope image of the base material for dental impression material is about 5 μm or more, or about 8 μm, from the viewpoint of giving good impression accuracy due to low permanent strain to the dental impression material. It is about 30 μm or less, or about 25 μm or less, or about 20 μm or less from the viewpoint of maintaining a relatively high shear stress or viscosity under a low shear rate.

The average particle size of diatomaceous earth is measured by the following method. That is, 20 diatomaceous earth particles are arbitrarily selected in an electron microscope (for example, scanning electron microscope) image with a field size of 350 μm × 250 μm of the base material. When selecting diatomaceous earth particles, it is preferable to select particles whose entire shape is imaged. Since the particles of diatomaceous earth usually have a unique geometric shape due to the origin of diatomaceous earth, they can be easily distinguished from the particles other than diatomaceous earth. Arbitrarily 20 particles of diatomaceous earth are selected in the field of view, the major axis (that is, the maximum transfer) is measured on the image, and the average value of 20 particles is taken as the average particle size of diatomaceous earth.

In a preferred embodiment, the cumulative distribution of diatomaceous soil 50% particle size median diameter as measured by a laser diffraction type particle size distribution measuring device is about 5 μm or more, or from the viewpoint of giving a good impression accuracy due to low permanent strain to the dental impression material. It may be about 8 μm or more, or about 10 μm or more, and may be about 30 μm or less, about 25 μm or less, or about 20 μm or less from the viewpoint of maintaining a high shear stress or viscosity under a low shear rate.

In a preferred embodiment, the bulk density of the diatomaceous earth may be from about 0.08 to about 0.29, or from about 0.1 to about 0.27, or from about 0.12 to about 0.25. The bulk density is a value measured in a cake bulk density measurement test.

As the silica particles, any of natural silica and synthetic silica, crystalline silica and amorphous silica, dry silica and wet silica can be used. In a preferred embodiment, the silica particles are precipitated silica from the viewpoint of dispersibility of the secondary aggregated particles.

In a preferred embodiment, the average primary particle size of the silica particles is about 10 nm to about 100 nm as measured from an electron microscopic image of the base material for dental impression material. Silica particles with such a particle size usually aggregate and have a larger secondary particle size. The fact that the average primary particle size is in the above range means that the silica particles in the base material exist as secondary particles in which a plurality of particles are aggregated in a state where no shearing force is applied, while when a shearing force is applied, the particles are between the particles. The agglomeration is released and the primary particles are dispersed in the base material, thereby imparting pseudoplasticity to the base material and significantly reducing the shear stress or viscosity of the base material under shearing force. It is advantageous in that it can be done. The particle size of the silica particles is preferably small from the viewpoint of increasing the difference in shear stress or viscosity of the base material between unsheared and sheared, and from this viewpoint, the average primary particle size is preferably about. It is 100 nm or less, or about 80 nm or less, or about 60 nm or less. On the other hand, from the viewpoint of maintaining a relatively high shear stress or viscosity of the base material under non-shearing, the average primary particle size is preferably about 10 nm or more, or about 20 nm or more, or about 30 nm or more.

The average primary particle size of the silica particles is measured by the following method. That is, 20 silica primary particles are arbitrarily selected in an electron microscope (for example, scanning electron microscope) image with a field size of 1.5 μm × 1.2 μm of the base material. The silica particles usually aggregate in the base material to form secondary particles, but the morphology of the individual primary particles constituting the secondary particles can be discriminated on an electron microscope image. Arbitrarily 20 primary particles whose contours as primary particles can be clearly confirmed on the entire circumference on the electron microscope image are arbitrarily selected in the field of view, and the major axis (that is, the maximum transfer) is measured on the image, and the number of 20 particles is measured. Let the average value be the average primary particle size of the silica particles.

In a preferred embodiment, the BET specific surface area of the silica particles is about 10 to about 1000, or about 100 to about 800, or about 300 to about 600.

The silica particles may be surface-treated or unsurface-treated. For example, the surface-treated silica particles may be epoxysilane, acrylicsilane, aminosilane, vinylsilane, or phenylsilane.

The mass ratio of diatomaceous earth and silica particles in the base material for dental impression material is about 4/1 to about 1/1. From the viewpoint of reducing the permanent strain of the dental impression material due to the contribution of diatomaceous earth, the above ratio is about 1/1 or more, preferably about 1.2 / 1 or more, or about 1.5 / 1 or more. Further, from the viewpoint of obtaining a large shear stress under a low shear rate and a small shear stress under a high shear rate due to the contribution of silica particles, the above ratio is about 4/1 or less, preferably about 3/1 or less, or about 2 .5 / 1 or less.

In a preferred embodiment, the content of diatomaceous earth in the base material for dental impression material is about 8% by mass or more, or about 10% by mass or more, or about 12% by mass or more from the viewpoint of obtaining a good effect by blending the diatomaceous earth. From the viewpoint of preventing the permanent strain of the dental impression material from becoming too small and obtaining good impression accuracy, it is about 25% by mass or less, about 20% by mass or less, or about 17% by mass or less.

In a preferred embodiment, the content of the silica particles in the base material for the dental impression material is about 3% by mass or more, about 5% by mass or more, or about 6% by mass from the viewpoint of obtaining a good effect by blending the silica particles. As described above, from the viewpoint of preventing the permanent strain of the dental impression material from becoming too small and obtaining good impression accuracy, it is about 20% by mass or less, about 15% by mass or less, or about 10% by mass or less.

In a preferred embodiment, the total content of diatomaceous soil and silica particles in the base material for dental impression material is about 15% by mass or more, or about 15% by mass or more, from the viewpoint of obtaining good mechanical strength of the dental impression material and relatively small permanent strain. About 30% by mass or more, or about 20% by mass or more, and from the viewpoint of preventing the permanent distortion of the dental impression material from becoming too small and obtaining good impression accuracy, about 30% by mass or less, or about 26% by mass. Or less, or about 24% by mass or less.

In the base material of the present disclosure, the values of the amount and ratio of diatomaceous earth and silica particles are the amount of diatomaceous earth and silica particles used (that is, the amount charged) at the time of manufacturing the base material, or the amount of diatomaceous earth and silica particles in the base material. It suffices to satisfy at least one of the measured values of.

The filler contained in the base material for dental impression material of the present disclosure may be substantially composed of diatomaceous earth and silica particles, and may further contain alumina or the like as an additional filler. In a preferred embodiment, the filler is substantially composed of diatomaceous earth and silica particles.

The base material for dental impression material of the present disclosure contains water and alginate. Alginate functions as a gelling agent. Examples of the alginate include potassium and sodium salts of alginic acid. In a preferred embodiment, the alginate is potassium alginate.

In a preferred embodiment, the amount of alginate in 100% by weight of the substrate is from about 1 to about 10% by weight. From the viewpoint of giving good physical properties to the impression material, the amount is preferably about 1% by mass or more, about 2% by mass or more, or about 3% by mass or more, and preferably about 10% by mass or less, about. It is 8% by mass or less, or about 7% by mass or less.

The water may be purified water, deionized water, or the like. In a preferred embodiment, the amount of water in 100% by weight of the substrate is from about 50 to about 90% by weight. The amount is preferably about 50% by mass from the viewpoint of avoiding the viscosity of the base material becoming too high and facilitating the kneading of the base material and the curing material and the application of the impression material (that is, impression taking). The above, or about 55% by mass or more, or about 60% by mass or more, avoiding the viscosity of the base material becoming too low, facilitating the kneading of the base material and the curing material and the application of the impression material, and further. From the viewpoint of improving the physical properties of the impression material, it is preferably about 90% by mass or less, about 85% by mass or less, or about 80% by mass or less.

The substrate may further contain additional components in addition to water, alginate, and filler. Examples of the additional component include preservatives, curing retardants, fragrances, surfactants and the like, and one or more of these can be used.

Examples of the preservative include methyl paraoxybenzoate, propyl paraoxybenzoate, and the like. In a preferred embodiment, the amount of preservative in 100% by weight of the substrate is from about 0.01 to about 1.0% by weight.

Examples of the curing retarder include alkali metal phosphates (eg, trisodium phosphate, tripotassium phosphate, sodium pyrophosphate, sodium tripolyphosphate, etc.) and alkali metal oxalates (eg, sodium oxalate, potassium oxalate, etc.). , Alkali metal carbonates (eg sodium carbonate, potassium carbonate, etc.) and the like. Of these, sodium pyrophosphate decahydrate is preferable from the viewpoint of ease of handling. In a preferred embodiment, the amount of curing retardant in 100% by weight of the substrate is from about 0.1 to about 5% by weight. The amount is preferably about 0.1% by mass or more, or about 0.3% by mass or more, or about, from the viewpoint of avoiding the impression material from curing too quickly and ensuring a good operation time at the time of impression collection. It is 0.4% by mass or more, and preferably about 5% by mass or less, or about 2% by mass or less, or about 1% by mass or less from the viewpoint of good curing of the impression material.

Examples of the fragrance include peppermint flavor and apple flavor. In a preferred embodiment, the amount of fragrance in 100% by weight of the substrate is from about 0.01 to about 1.0% by weight.

Surfactants include anionic surfactants (eg alkyl sulfonates, alkyl benzene sulfonates, alkyl ether carboxylates, etc.), cationic surfactants (eg alkyl amine salts, quaternary ammonium salts, etc.), amphoteric. Surfactants (eg aminocarboxylates, etc.) and nonionic surfactants (eg, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene-polyoxypropylene block polymers, polyoxyethylene glycerin fatty acid esters, etc. Examples thereof include polyoxyglycerin fatty acid ester, sorbitan fatty acid ester, sucrose ester, polyoxydiethylene alkylamine, block polymer of polysiloxanes and polyoxyethylenes). In a preferred embodiment, the amount of surfactant in 100% by weight of the substrate is from about 0.1 to about 5% by weight. The amount is preferably about 0.1% by mass or more, or about 0.2% by mass, from the viewpoint of avoiding separation of the hydrophobic component and the hydrophilic component in the base material and obtaining good storage stability. The above, or about 0.3% by mass or more, and from the viewpoint of ensuring a good content of other components of the base material, preferably about 5% by mass or less, or about 2% by mass or less, or about 1% by mass. % Or less.

In a preferred embodiment, the substrate is
Water: Approximately 65% by mass to approximately 80% by mass,
Alginate: about 4% by mass to about 5% by mass, and filler: about 15% by mass to about 30% by mass, and
Preservatives as optional ingredients: about 0% by mass to about 1% by mass,
Curing retarder: Approximately 0% by mass to approximately 1% by mass,
Fragrance: about 0% by mass to about 0.1% by mass, and surfactant: about 0% by mass to about 1% by mass,
Includes one or more of.

In a preferred embodiment, the maximum value of the shear stress of the substrate when the ^{shear rate was increased from 1 second-1} to 100 seconds- ^{1 increased the shear rate from more than 100 seconds-1} to 1000 seconds- ¹ . Greater than the maximum shear stress of the substrate at the time. Such a base material has both a large shear stress under a low shear rate and a small shear stress under a high shear rate, and is therefore advantageous from the viewpoint of achieving both good handleability and good quality. ..

In a preferred embodiment, the ^{maximum value when the shear rate is increased from 1 second-1} to 100 seconds- ¹ is about 200 Pa · s or more, or about 300 Pa or more, or about 400 Pa or more from the viewpoint of good handleability. Is. On the other hand, the shear rate is increased ^{from 1 second-1} to 100 seconds- ¹ from the viewpoint that the handleability of the base material and dental impression material tends to decrease even when the shear stress under a low shear rate is too high. The maximum value at the time is preferably about 4000 Pa or less, about 3000 Pa or less, or about 2000 Pa or less.

In a preferred embodiment, the ^{maximum value when the shear rate is increased from more than 100 seconds-1} to 1000 seconds- ¹ is small from the viewpoint of obtaining a base material for dental impression material and a dental impression material having few bubbles and excellent quality. Moderately preferable. In a preferred embodiment, the shear rate is ^{increased from more than 100 seconds-1} to 1000 seconds- ¹ provided that the shear rate is less than the maximum value of the shear stress when increased ^{from 1 second-1} to 100 seconds- ^1. The maximum value of the shear stress at that time is about 1500 Pa or less, or about 1250 Pa or less, or about 1000 Pa or less.

In a preferred embodiment, in the measurement of shear stress by a rheometer, the ^{viscosity derived from the shear stress at a shear rate of 1000 seconds-1} is about 1.5 Pa · s or less from the viewpoint of obtaining a high-quality base material and dental impression material. , Or about 1.25 Pa · s or less, or about 1.0 Pa · s or less.

The shear stress and viscosity are values obtained by setting the shear rate from 0 to 1500 on a cone plate having a measurement temperature of 25 ° C., a Delay time of 5 seconds, an integral of 5 seconds, and 4/40 using a rheometer.

<Dental impression material>
One aspect of the present disclosure provides a dental impression material containing the substrate and the curing material according to the one aspect of the present disclosure as described above. As the curing material, various conventionally known compositions can be used as the curing material for the alginate-based dental impression material. In a typical embodiment, the curing material comprises a solvent and a gelling agent. The curing material may further contain a curing retarder, a surfactant, a surface modifier, a colorant, a filler and the like.

Examples of the solvent include hydrocarbons, alcohols, phenols, fatty acids or esters thereof, hydrophobic polymers, polyethers and the like.

Hydrocarbons include aliphatic chain hydrocarbons such as hexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, kerosine, 2,7-dimethyloctane, 1-octene; and cycloheptane, Examples thereof include alicyclic hydrocarbons such as cyclononane. The hydrocarbon can be a hydrocarbon mixture such as liquid paraffin.

Examples of the alcohol include saturated fatty alcohols such as 1-hexanol and 1-octanol; unsaturated fatty alcohols such as citronellol and oleyl alcohol; and aromatic alcohols such as benzyl alcohol. Examples of phenols include cresol and the like.

Examples of the fatty acid or an ester thereof include saturated fatty acids such as hexanoic acid and octanoic acid; unsaturated fatty acids such as oleic acid and linoleic acid; and fatty acid esters such as ethyl octanate, dibutyl phthalate and oleic acid glyceride.

Examples of the hydrophobic polymer include polysiloxane.

Of these, liquid paraffin is preferable from the viewpoints of good hydrophobicity, ease of acquisition and handling, safety to the living body, and the like.

Examples of the polyether include linear or branched polyethers, preferably polyalkylene glycols. Examples of the polyalkylene glycol include polyethylene glycol and polypropylene glycol. Among them, polyethylene glycol is preferable because it has excellent hydrophilicity.

In a preferred embodiment, the amount of solvent in 100% by mass of the curing material is from about 10% by mass to about 50% by mass. From the viewpoint of facilitating kneading between the base material and the cured material, the amount is preferably about 10% by mass or more, or about 13% by mass or more, about 15% by mass or more, about 18% by mass or more, and about 20. By mass% or more, about 23% by mass or more, about 26% by mass or more, or about 30% by mass or more, from the viewpoint of obtaining good storage stability of the cured material, and the content of other components of the cured material is good. From the viewpoint of securing, it is preferably about 50% by mass or less, or about 47% by mass or less, about 43% by mass or less, or about 40% by mass or less, or about 37% by mass or less.

As the gelling agent, generally, a metal compound having a divalent value or higher can be used. Specific examples thereof include calcium sulfate (for example, calcium sulfate hemihydrate, calcium sulfate anhydride, calcium sulfate dihydrate, etc.), magnesium sulfate and the like. Above all, calcium sulfate hemihydrate is preferable in that it obtains good curability.

In a preferred embodiment, the amount of gelling agent in 100% by weight of the curing material is from about 20 to about 70% by weight. From the viewpoint of obtaining good curability, the amount is preferably about 20% by mass or more, or about 30% by mass or more, or about 40% by mass or more, or about 45% by mass or more, and the dental impression material is good. From the viewpoint of obtaining physical properties, it is preferably about 70% by mass or less, or about 60% by mass or less, or about 55% by mass or less, or about 50% by mass or less.

Examples of the curing retarder and the surfactant that can be used for the curing material include the same compounds as described above for the base material.

In a preferred embodiment, the amount of curing retardant in 100% by weight of the curing material is about 0.1 to about 10% by weight. The amount is preferably about 0.1% by mass or more, or about 0.5% by mass or more, or about, from the viewpoint of avoiding the impression material from curing too quickly and ensuring a good operation time at the time of impression collection. It is 0.8% by mass or more, and preferably about 10% by mass or less, or about 8% by mass or less, or about 5% by mass or less from the viewpoint of good curing of the dental impression material.

In a preferred embodiment, the amount of surfactant in 100% by weight of the cured material is about 0.1 to about 10% by weight. The amount is preferably about 0.1% by mass or more, or about 0.5% by mass, from the viewpoint of avoiding separation of the hydrophobic component and the hydrophilic component in the curing material and obtaining good storage stability. The above, or about 0.8% by mass or more, preferably about 10% by mass or less, or about 8% by mass or less, or about 5% by mass from the viewpoint of ensuring a good content of other components of the cured material. % Or less.

The surface modifier has the effect of smoothing the surface of the impression material and improving the impression accuracy. Examples of the surface modifier include inorganic fluoride compounds such as potassium titanium fluoride and potassium silica fluoride, and metal oxides such as magnesium oxide and zinc oxide. Of these, potassium titanium fluoride is preferable from the viewpoint of improving impression accuracy. In a preferred embodiment, the amount of the surface modifier in 100% by mass of the curing material is about 0.5 to about 30% by mass, or about 1 to about 27% by mass, about 5 to 5 from the viewpoint of obtaining good impression accuracy. It is about 24% by mass, or about 9 to about 18% by mass.

Examples of the colorant include Red No. 226, Red No. 3, Blue No. 1, Green No. 3, and the like. In a preferred embodiment, the amount of colorant in 100% by mass of the curing material is from about 0.01 to about 1.0% by mass.

Examples of the filler include diatomaceous earth, silica, alumina and the like. In a preferred embodiment, the amount of filler in 100% by weight of the cured material is from about 1 to about 40% by weight. The amount is preferably about 2% by mass or more, or about 5% by mass or more, from the viewpoint of increasing the viscosity of the curing material and improving the physical properties of the impression material, and contains other components of the curing material. From the viewpoint of ensuring a good rate, it is preferably about 20% by mass or less, or about 8% by mass or less.

<Manufacturing of base material for dental impression material, curing material and dental impression material>
The base material for dental impression material and the curing material can be produced, for example, by a method of mixing the compounding components with a known stirring mixer. As the stirring mixer, a ball mill, a ribbon mixer, a conider, an internal mixer, a screw kneader, a henschel mixer, a universal mixer, a radige mixer, a butterfly mixer and the like can be used. The dental impression material of the present disclosure can be provided as a combination of a base material produced as described above and a curing material. In a typical embodiment, the base material and the curing material are each provided in a package, and these packages are mounted on a known automatic kneader so that the base material and the curing material are in a predetermined ratio. Impression material paste is provided by automatic kneading.

In a preferred embodiment, the permanent strain of the dental impression material is about 5.0% or less, or about 4.5% or less, or about 4.0% or less from the viewpoint of enabling precise impression taking.

The permanent strain and elastic strain of the present disclosure are values measured in accordance with JIS T6505.

Hereinafter, embodiments of the present invention will be further described with reference to examples, but the present invention is not limited to these examples.

<Preparation of curing material paste and base material paste>
Each of the compounding components (for the curing material) shown in Table 1 and the compounding components (for the base material) shown in Table 2 were mixed at room temperature by a conventional method to obtain a curing material paste and a base material paste.

<Evaluation>
(1) Particle size of diatomaceous soil and silica particles Using a scanning electron microscope (“S4800” manufactured by Hitachi High-Technologies Co., Ltd.), an acceleration voltage of 3.0 kV and an observation magnification of 4000 times, a substrate of 350 μm × 250 μm. An electron microscope image having a visual field size of 1.5 μm × 1.2 μm was obtained at a visual field size and an observation magnification of 80,000 times. Twenty diatomaceous earth particles were arbitrarily selected from the entire microscope image at an observation magnification of 4000 times, and 20 silica primary particles were arbitrarily selected from the electron microscope image at an observation magnification of 80,000 times. The silica particles aggregated in the base material to form secondary particles, but 20 primary particles whose contours can be clearly confirmed all around were selected. For each of the diatomaceous earth and the silica particles, 20 major axes were measured on the image. The average values of the 20 particles were taken as the average particle size of diatomaceous earth and the average primary particle size of silica particles, respectively. The results are shown in Table 2.

(2) Permanent strain of dental impression material The curing material paste obtained above and each of the base material pastes according to the examples and comparative examples obtained above are kneaded at room temperature by a conventional method to obtain a dental impression material. Prepared.

The permanent strain of the obtained dental impression material was measured according to JIS T6505. The results are shown in Table 2.

(3) Shear Stress and Viscosity of Base Material Paste The shear stress and viscosity of the base material paste according to Examples and Comparative Examples of the formulations shown in Table 2 were measured using a rheometer (Gemini 150/200 manufactured by Malvern). .. The measurement shear rate range is 1 second- ^{1 to} 1500 seconds- ¹ . The results are shown in Table 2.

As shown in Table 2, in each example in which the ratio of diatomaceous soil / silica particles is in the range of 4/1 to 1/1, the shear rate is lower than in each comparative example in which the ratio is outside the above range. The maximum value of the shear stress at a shear rate of 1 second- ^{1 to} 100 seconds- ¹ was large and the maximum value of the shear stress at a high shear rate of 100 seconds- ^{1 to} 1000 seconds- ¹ was small. .. Further, in each example, the permanent strain of the dental impression material was 5% or less, which was a relatively small good value. Further, in each example, it was confirmed visually that no air bubbles were present in the base material paste obtained by mixing the compounding components. In Comparative Examples 1, 3 and 4 in which silica particles were not used, a large shear stress was exhibited at a high shear rate. On the other hand, Comparative Example 2 in which diatomaceous earth was not used showed a large permanent strain.

The dental impression base material of the present disclosure is suitably applied to an alginate-based dental impression material.

Claims (6)

A base material for dental impression materials containing water, alginate, and fillers.
The filler contains diatomaceous earth and silica particles.
The mass ratio of the diatomaceous earth and the silica particles in the base material for dental impression material is 4/1 to 1/1.
Base material for dental impression material. In the measurement of shear stress by rheometer, the maximum value of shear stress when the shear rate was increased ^{from 1 second-1} to 100 seconds- ^{1 increased the shear rate from more than 100 seconds-1} to 1000 seconds- ¹ . The base material for a dental impression material according to claim 1, which is larger than the maximum value of the shear stress at the time. The group for dental impression material according to claim 1 or 2, wherein in the shear stress measurement by a rheometer, the ^{viscosity derived from the shear stress at a shear rate of 1000 seconds-1 is 0.3 Pa · s to 1.4 Pa · s.} Material. The base material for dental impression material according to any one of claims 1 to 3, wherein the total content of the diatomaceous earth and the silica particles in the base material for dental impression material is 15% by mass to 30% by mass. .. Claims 1 to 4 in which the average primary particle size of the silica particles is 10 nm to 100 nm and the average particle size of the diatomaceous soil is 5 μm to 30 μm when measured from an electron microscope image of the base material for dental impression material. The base material for dental impression material according to any one of the above. A dental impression material containing the base material for dental impression material according to any one of claims 1 to 5 and a curing material.