JP2018108986A - Denture base material, denture base and production method thereof, denture plate and production method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a denture base material having excellent hardness (flexural modulus) and when made into a denture base having excellent durability (yield point strength of compression test).SOLUTION: The denture base material comprises a polymer component including an acrylic resin which has, when made into a test piece with a length of 80 mm, a width of 10 mm, and a thickness of 4 mm, a flexural strength of 110 MPa or more as measured by a three point flexure test under the conditions of a test speed of 2 mm/min, and a fulcrum distance of 64 mm conforming to JIS K7171 (2008), and when made into a notched test piece with a length of 39 mm, a height of 8 mm, and a width of 4 mm, has a maximum stress intensity factor of 1.9 MPa mor more as measured in a fracture toughness test in a flexure test under the conditions of a test speed of 1 mm/minute conforming to JIS T6501 (2012), and the total destruction work is 900 J/m.SELECTED DRAWING: None

Description

  The present invention relates to a denture base material, a denture base and a manufacturing method thereof, and a denture base and a manufacturing method thereof.

BACKGROUND ART Conventionally, a denture having a dental prosthesis and a denture base for fixing the artificial tooth has been widely used. As the denture base, a denture base containing a polymer is widely used.
A denture base containing a polymer is produced by pouring a curable resin into a gypsum mold composed of an upper mold and a lower mold, and then curing the curable resin (for example, photopolymerization, thermal polymerization, etc.). It was.
In recent years, for example, a method for producing the denture base by cutting a hardened polymer (resin) using a CAD (Computer Aided Design) / CAM (Computer Aided Manufacturing) system or the like is also known (for example, (See Patent Documents 1 and 2).

International Publication No. 2010/058822 Pamphlet JP-T-2006-521136

By the way, if a denture base provided with a denture base containing a polymer is used for a long time, the denture base may break. According to the inventor's study, the ease of denture base fracture has a correlation with the durability of the denture base (yield point strength of the compression test), and the durability of the denture base (yield point strength of the compression test) is It was found that the higher the denture base, the less likely it was to break.
On the other hand, it is desirable to use a hard material as the denture base material in consideration of the workability in producing the denture base and the practicality of the denture having a denture base.

This invention is made | formed in view of the above, and makes it a subject to achieve the following objectives.
That is, an object of the present invention is to provide a denture base material which is excellent in hardness (flexural modulus) and excellent in durability (yield point strength of compression test) when used as a denture base.
Another object of the present invention is to provide a denture base that can be manufactured using a denture base material excellent in hardness (flexural modulus) and excellent in durability (yield point strength of compression test), and a method for manufacturing the denture base. It is to be.
In addition, the object of the present invention is to provide a denture base that can be manufactured using a denture base material excellent in hardness (flexural modulus) and has excellent durability (yield point strength in compression test). It is an object of the present invention to provide a denture with a denture and a method for producing the denture that can prevent the denture from being broken by use.

  Specific means for achieving the above object are as follows.

<1> Contains a polymer component including an acrylic resin,
Bending strength measured by a three-point bending test under the conditions of a test speed of 2 mm / min and a fulcrum distance of 64 mm in accordance with JIS K7171 (2008) when a test piece having a length of 80 mm, a width of 10 mm, and a thickness of 4 mm is used. Is 110 MPa or more,
Maximum stress expansion measured by a fracture toughness test by a bending test under a test speed of 1 mm / min in accordance with JIS T6501 (2012) when a notched specimen having a length of 39 mm, a height of 8 mm, and a width of 4 mm is used. A denture base material having a coefficient of 1.9 MPa · m ^1/2 or more and a total fracture work of 900 J / m ² or more.
<2> The denture base material according to <1>, wherein the bending strength is 200 MPa or less.
<3> The denture base material according to <1> or <2>, in which the maximum stress intensity factor is 3.5 MPa · m ^1/2 or less and the total fracture work is 2500 J / m ² or less.
<4> When a test piece with a single notch having a length of 80 mm, a width of 10 mm, a remaining width of 8 mm, and a thickness of 4 mm provided with a notch having a shape A defined in JIS K7111-1 (2012) is JIS K7111. -1 (2012), the impact strength measured by the Charpy impact test under the condition of edgewise impact is 1.6 kJ / m ² or more, according to any one of <1> to <3> Denture base material.
<5> The denture base material according to any one of <1> to <4>, wherein the polymer component has a weight average molecular weight of 1,200,000 or more.
<6> The denture base material according to any one of <1> to <5>, wherein the polymer component further includes a rubber.
<7> The denture base material according to <6>, wherein the rubber includes a graft polymer obtained by graft polymerization of a thermoplastic resin component on a rubbery polymer having a crosslinked structure.
<8> The denture base material according to <6> or <7>, wherein the rubber includes a graft polymer obtained by graft polymerization of a thermoplastic resin component to a butadiene-based (co) polymer.
<9> The denture base material according to any one of <6> to <8>, wherein the rubber content is 1% by mass to 10% by mass with respect to the total amount of the denture base material.
<10> The denture base material according to any one of <1> to <9>, wherein the content of the acrylic resin is 90% by mass or more based on the total amount of the denture base material.
<11> The denture base material according to any one of <1> to <10>, wherein the acrylic resin is a polymer containing 95% by mass or more of a structural unit derived from a monofunctional acrylic monomer. .
<12> The denture base material according to <11>, wherein the monofunctional acrylic monomer is at least one monomer selected from the group consisting of methacrylic acid and alkyl methacrylate.
<13> The monofunctional acrylic monomer comprises methacrylic acid and an alkyl methacrylate.
Denture base material as described in <11> whose quantity of the said methacrylic acid with respect to the total amount of the said methacrylic acid and the said methacrylic acid alkylester is 0.1 to 15 mass%.
<14> The denture base material according to any one of <1> to <13>, wherein the acrylic resin is a copolymer of methacrylic acid and methyl methacrylate.
<15> A denture base comprising the denture base material according to any one of <1> to <14>.
<16> A denture having a denture base according to <15> and an artificial tooth fixed to the denture base.
<17> A method for manufacturing a denture base comprising a cutting step of obtaining a denture base by cutting the denture base material according to any one of <1> to <14>.
<18> a cutting step of obtaining a denture base by cutting the denture base material according to any one of <1> to <14>;
A fixing step of fixing artificial teeth to the denture base;
The manufacturing method of the denture which has this.

In the present specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
Moreover, in this specification, the yield point strength of the compression test may be simply abbreviated as “yield point strength”. That is, in this specification, the word “yield point strength” simply means the yield point strength of the compression test.

ADVANTAGE OF THE INVENTION According to this invention, the material for denture bases excellent in hardness (bending elastic modulus) and excellent in the durability (yield point strength of a compression test) when it is set as a denture base is provided.
Moreover, according to this invention, the denture base which can be manufactured using the material for denture bases excellent in hardness (bending elastic modulus), and was excellent in durability (yield point strength of a compression test), and its manufacturing method are provided. Is done.
In addition, according to the present invention, a denture base that can be manufactured using a denture base material excellent in hardness (flexural modulus) and has excellent durability (yield point strength of compression test) is provided for a long time. Provided are a denture with a denture and a method for producing the same.

It is a perspective view which shows notionally an example of the denture of the present invention. It is a graph which shows the relationship between the minute maximum stress intensity | strength coefficient of a denture base, and the maximum stress intensity | strength coefficient of a denture base material in an example of this invention. It is a graph which shows the relationship between the micro total destruction work of the denture base, and the total destruction work of the denture base material in an example of this invention.

[Material for denture base]
The denture base material of this embodiment contains a polymer component containing an acrylic resin, and is a test conforming to JIS K7171 (2008) when it is a test piece having a length of 80 mm, a width of 10 mm, and a thickness of 4 mm. When a bending strength measured by a three-point bending test under the conditions of a speed of 2 mm / min and a fulcrum distance of 64 mm is 110 MPa or more, a notched test piece having a length of 39 mm, a height of 8 mm, and a width of 4 mm is JIS. The maximum stress intensity factor measured by a fracture toughness test by a bending test under a test speed of 1 mm / min in accordance with T6501 (2012) is 1.9 MPa · m ^1/2 or more, and the total fracture work is 900 J / M ² or more.
According to the denture base material of this embodiment, it is excellent in hardness (bending elastic modulus). Therefore, a denture base excellent in hardness (flexural modulus) can be manufactured, and the workability in producing a denture base and the practicality of a denture with a denture base are good.
Moreover, according to the denture base material of this embodiment, durability (yield point strength of a compression test) when it is set as a denture base improves. Thereby, the fracture of the denture base due to long-term use is suppressed. The reason for this is not clear, but is presumed as follows.
That is, the shape of the denture base is a complicated shape that matches the oral cavity of the denture user. For this reason, the force applied to the denture base by occlusion concentrates locally on a part of the denture base, and as a result, even when a hard material (a material having a high elastic modulus) is used as the denture base material The denture base is considered to break. Moreover, when a fine crack generate | occur | produces in a denture base for some reason during use, it is thought that a denture base tends to fracture | rupture from a crack.
With regard to these points, the denture base material is not simply a “hard material” (a material with a high elastic modulus), but also has a high durability or a force applied from multiple directions. By using a material that does not easily crack, that is, a bending strength in a three-point bending test, and a material having a high maximum stress intensity factor and total fracture work in a fracture toughness test, (Yield point strength) can be improved, and it is considered that the denture base can be prevented from breaking when the denture is used for a long time.

  When the denture base material of this embodiment is a test piece having a length of 80 mm, a width of 10 mm, and a thickness of 4 mm (80 mm × 10 mm × 4 mm size), the test speed is 2 mm / min in accordance with JIS K7171 (2008). The bending strength measured by a three-point bending test under the condition of a fulcrum distance of 64 mm is 110 MPa or more.

The said test piece can be extract | collected by methods, such as cutting, from the denture base material of this embodiment. Hereinafter, “bending strength in a three-point bending test” may be simply referred to as “bending strength”.
When the denture base material has a bending strength of 110 MPa or more, the durability (yield point strength of the compression test) is remarkably improved and the hardness (bending elastic modulus) is excellent when the denture base is used.
The bending strength can be measured using, for example, a 5-bend testing machine 2001-5 manufactured by Intesco.

  Although there is no restriction | limiting in particular in the upper limit of the bending strength in this embodiment, From the viewpoint of cutting workability, it is preferable that the said bending strength is 200 Mpa or less.

When the denture base material of the present embodiment is a notched test piece having a length of 39 mm, a height of 8 mm, and a width of 4 mm, it is based on a bending test under a test speed of 1 mm / min in accordance with JIS T6501 (2012). The maximum stress intensity factor measured by the fracture toughness test is 1.9 MPa · m ^1/2 or more, and the total fracture work is 900 J / m ² or more.

The said test piece can be extract | collected by methods, such as cutting, from the denture base material of this embodiment. Hereinafter, the “maximum stress intensity factor in the fracture toughness test” may be simply referred to as “maximum stress intensity factor”, and the “total fracture work in the fracture toughness test” may be simply referred to as “total fracture work”.
When the maximum stress intensity factor of the denture base material is 1.9 MPa · m ^1/2 or more and the total fracture work is 900 J / m ² or more, the toughness of the denture base is improved, and the denture base The durability (yield point strength of the compression test) is improved.
Although there is no restriction | limiting in particular in the upper limit of the said maximum stress intensity | strength coefficient, From a viewpoint of aiming at balance with hardness (bending elastic modulus), it is preferable that an upper limit is 4.0 MPa * m < ^1/2 > or less, for example. more preferably .7MPa ^{· m 1/2} or less, and more preferably 3.5 MPa ^{· m 1/2} or less.
Moreover, although there is no restriction | limiting in particular in the upper limit of the said total fracture work, From a viewpoint of aiming at balance with hardness (bending elastic modulus), it is preferable that an upper limit is 3000 J / m < ² > or less, for example, 2500 J / m < ² >. Or less, more preferably 2000 J / m ² or less.
The maximum stress intensity factor and total fracture work can be measured using, for example, a universal testing machine 210X manufactured by Intesco.

The denture base material of this embodiment is a test piece with a single notch having a length of 80 mm, a width of 10 mm, a remaining width of 8 mm, and a thickness of 4 mm provided with a notch of shape A defined in JIS K7111-1 (2012). The impact strength measured by the Charpy impact test under the condition of edgewise impact based on JIS K7111-1 (2012) is preferably 1.6 kJ / m ² or more, and the impact resistance ( from the viewpoint of remarkably improving the fracture weight) of ball drop test, more preferably that is greater than 2.64kJ / ^{m 2,} further preferably 2.70kJ / ^{m 2} or more.

The test piece with a single notch can be collected from the denture base material of the present embodiment by a method such as cutting.
When the impact strength is 1.6 kJ / m ² or more, impact resistance (destructive weight in a falling ball test) when a denture base is used is improved.
In particular, when the impact strength exceeds 2.64 kJ / m ² (preferably 2.70 kJ / m ² or more), the impact resistance (destructive weight in the falling ball test) when the denture base is used is significantly improved.
Although there is no restriction | limiting in particular in the upper limit of the said impact strength, For example, an upper limit can be 6.0 kJ / m < ² > or less.
The impact strength can be measured using, for example, an impact tester DG-UB type with a thermostatic bath manufactured by Toyo Seiki Seisakusho.

Further, the denture base material of the present embodiment preferably has a flexural modulus of 2700 MPa to 4000 MPa, and more preferably 3000 MPa to 3700 MPa.
Here, the “flexural modulus” refers to a flexural modulus measured by a three-point bending test under the same conditions as the “bending strength” described above. The calculation method of the flexural modulus is the “secant method”.

<Polymer component>
The denture base material of this embodiment contains a polymer component including an acrylic resin.
The weight average molecular weight (Mw) of the polymer component in the present embodiment is preferably 1.2 million or more.
Mw here means Mw of the polymer component (whole).
Needless to say, when the polymer component is composed only of an acrylic resin, the Mw of the polymer component and the Mw of the acrylic resin coincide. Further, Mw when the polymer component is made of an acrylic resin and rubber is the Mw of the entire polymer component (acrylic resin and rubber).
When the polymer component Mw is 1,200,000 or more, the bending strength of the denture base material is likely to be improved, and as a result, the durability (yield point strength) of the denture base is easily improved.
Further, the Mw of the polymer component being 1.2 million or more is advantageous also in terms of machinability when producing a denture base by cutting (for example, suppressing at least one of cracking and chipping during cutting). is there.
The Mw of the polymer component is more preferably 1.3 million or more, and further preferably 1.4 million or more, from the viewpoint of further improving the bending strength. The Mw of the polymer component is usually preferably adjusted to 8 million or less from the viewpoint of productivity.

  The polymer component in the present embodiment preferably has a molecular weight distribution (Mw / Mn) of 1.1 to 7.0, more preferably 1.5 to 6.0, and 2.0 to 5 More preferably, it is .5.

The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) in this specification refer to the values measured by the following GPC measurement method using gel permeation chromatograph (GPC), respectively.
-GPC measuring device-
LC-10AD manufactured by Shimadzu
-Column-
Shodex K-806L 30 cm x 2-Preparation of Sample-
A polymer component to be measured is dissolved in a solvent (tetrahydrofuran) at room temperature (20 ° C. to 30 ° C.) to prepare a sample solution having a concentration of 0.1% (w / v).
-Measurement conditions-
100 μL of the sample solution was added to a mobile phase (for example, tetrahydrofuran), a column temperature of 40 ° C., 1.0 mL / min. Into the column at a flow rate of.
The sample concentration in the sample solution separated by the column is measured with a differential refractometer (RI-101). A universal calibration curve is prepared with a polymethyl methacrylate standard sample, and the weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw / Mn) of the polymer component are calculated.
For the analysis, for example, data processing software Empor2 (manufactured by Waters) can be used.

  In addition, the acrylic resin contained in the polymer component is an acrylic resin, oligomer or prepolymer obtained by polymerizing a monomer in that the polymer component can easily achieve a weight average molecular weight (Mw) of 1,200,000 or more. An acrylic resin obtained by polymerizing the above, or an acrylic resin obtained by polymerizing a mixture of an oligomer or prepolymer and a monomer is preferred. As the oligomer or the prepolymer, an oligomer or prepolymer having fluidity at room temperature is particularly suitable.

A typical denture acrylic resin is an acrylic resin obtained by polymerizing a mixture of a polymer that is solid at room temperature and a monomer.
However, when an acrylic resin obtained by polymerizing a mixture of a polymer that is solid at room temperature and a monomer is used as the acrylic resin in the present embodiment, the Mw of the polymer component including the acrylic resin is 1.2 million or more. Tend to be difficult.
For example, a denture base made of a normal denture acrylic resin is a mixture of an acrylic polymer with a relatively high molecular weight, which is a solid powder at room temperature, a monomer of an acrylic compound, and a polymerization initiator. Then, after polymerizing to a fluid state, it is prepared by putting it in a plaster mold or the like and curing it by heating or the like. This method for producing a denture base is usually performed by a dental technician and has an advantage that it is convenient for a dental technician because the polymerization rate is high. However, in this method, since the difference in molecular weight between the starting powder and the monomer is large, it is estimated that the Mw of the acrylic resin is difficult to increase.
For example, only an oligomer or prepolymer that is fluid at room temperature, or a monomer added to the oligomer or prepolymer, in the vicinity of the polymerization temperature of the oligomer or prepolymer, for example, several days to several By polymerizing over a week, the degree of polymerization and the uniformity of the polymerization can be improved. Thereby, it is considered that the Mw of the acrylic resin can be set to 1,200,000 or more, and as a result, the Mw of the polymer component can be set to 1,200,000 or more.
Moreover, when the polymer component in this embodiment contains rubber | gum, you may superpose | polymerize after mixing the oligomer or prepolymer, or what added the monomer to the oligomer or prepolymer, and rubber | gum.

(Acrylic resin)
The polymer component includes an acrylic resin.
Since the denture base material of this embodiment contains an acrylic resin with high transparency, it has the advantage that the degree of freedom of coloring is large. Moreover, since the denture base material of this embodiment contains acrylic resin, it has the advantage that it is excellent in adhesiveness with a commercially available acrylic artificial tooth.
The polymer component in this embodiment may contain only 1 type of acrylic resin, and may contain 2 or more types.

In this specification, the acrylic resin is a group consisting of a structural unit derived from acrylic acid, a structural unit derived from methacrylic acid, a structural unit derived from an acrylate ester, and a structural unit derived from a methacrylic acid ester. It refers to a polymer containing at least one selected.
That is, the acrylic resin in this specification is at least one selected from the group consisting of acrylic acid, methacrylic acid, acrylic ester, and methacrylic ester (hereinafter also referred to as “acrylic monomer”). It is a polymer obtained by polymerizing the monomer component containing.

The acrylic monomer that is at least part of the raw material of the acrylic resin may be a monofunctional acrylic monomer or a polyfunctional acrylic monomer.
Examples of the monofunctional acrylic monomer include acrylic acid, methacrylic acid, acrylic acid ester having one acryloyl group in one molecule, and methacrylic acid ester having one methacryloyl group in one molecule.
Examples of the polyfunctional acrylic monomer include acrylic acid esters containing two or more acryloyl groups in one molecule, and methacrylic acid esters containing two or more methacryloyl groups in one molecule.

More specifically, as the acrylic resin,
A homopolymer of acrylic acid,
A homopolymer of methacrylic acid,
Homopolymer of acrylic ester,
Methacrylic acid ester homopolymer,
A copolymer of acrylic acid and other monomers (for example, acrylic acid ester, methacrylic acid, methacrylic acid ester, α-olefin (for example, ethylene), etc.),
A copolymer of methacrylic acid and other monomers (for example, acrylic acid, acrylic acid ester, methacrylic acid ester, α-olefin (for example, ethylene), etc.),
A copolymer of an acrylic ester and another monomer (e.g., acrylic acid, methacrylic acid, methacrylic ester, [alpha] -olefin (e.g., ethylene), etc.),
Examples thereof include a copolymer of a methacrylic acid ester and another monomer (for example, acrylic acid, acrylic acid ester, methacrylic acid, α-olefin (for example, ethylene), etc.).

The acrylic acid ester is preferably an acrylic acid alkyl ester, more preferably a linear alkyl ester or branched alkyl ester of acrylic acid, and still more preferably a linear alkyl ester of acrylic acid.
Moreover, it is preferable that acrylic ester does not contain halogen atoms, such as a fluorine atom and a chlorine atom.
As the acrylate ester, an alkyl acrylate ester having 1 to 4 carbon atoms in the alkyl group contained in the alkyl ester moiety is more preferred, methyl acrylate and ethyl acrylate are more preferred, and methyl acrylate is particularly preferred.

As the methacrylic acid ester, methacrylic acid alkyl ester is preferable, methacrylic acid linear alkyl ester or branched alkyl ester is more preferable, and methacrylic acid linear alkyl ester is still more preferable.
Moreover, it is preferable that methacrylic acid ester does not contain halogen atoms, such as a fluorine atom and a chlorine atom.
The methacrylic acid ester is more preferably a methacrylic acid alkyl ester having 1 to 4 carbon atoms in the alkyl group contained in the alkyl ester moiety, more preferably methyl methacrylate or ethyl methacrylate, and particularly preferably methyl methacrylate.

The acrylic resin is preferably a polymer obtained by polymerizing a monomer component containing a monofunctional acrylic monomer from the viewpoint of reactivity and productivity.
Specifically, the acrylic resin contains 50% by mass or more (preferably 80% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more) of a structural unit derived from a monofunctional acrylic monomer. ).

The monofunctional acrylic monomer is preferably at least one selected from the group consisting of acrylic acid, methacrylic acid, alkyl acrylate ester, and alkyl methacrylate ester.
From the viewpoint of the denture base material and the physical properties (heat resistance) of the denture base, the monofunctional acrylic monomer is more preferably at least one selected from the group consisting of methacrylic acid and alkyl methacrylate esters. preferable.
The preferable range of each of the alkyl acrylate ester and the alkyl methacrylate ester is as described above.

A preferable form of the acrylic resin includes a form in which the monofunctional acrylic monomer is at least one monomer selected from the group consisting of methacrylic acid and alkyl methacrylate.
The acrylic resin is preferably a copolymer obtained by polymerizing a monomer component containing methacrylic acid and an alkyl methacrylate (that is, derived from a structural unit derived from methacrylic acid and an alkyl methacrylate). A copolymer containing a structural unit).
More preferably, it is a copolymer of methacrylic acid and alkyl methacrylate ester, and more preferably a copolymer of methacrylic acid and methyl methacrylate (methyl methacrylate) (hereinafter also referred to as “MMA-MAA copolymer”). ).

As a more preferred form of the acrylic resin, the monofunctional acrylic monomer is composed of methacrylic acid and alkyl methacrylate, and the amount of methacrylic acid relative to the total amount of methacrylic acid and alkyl methacrylate is 0.1 mass. The form which is% -15 mass% (preferably 1 mass% -15 mass%, More preferably, 5 mass% -15 mass%) is also mentioned.
As the acrylic resin of the preferred form, the monofunctional acrylic monomer is composed of methacrylic acid and methyl methacrylate, and the amount of methacrylic acid relative to the total amount of methacrylic acid and methyl methacrylate is from 0.1% by mass to A MMA-MAA copolymer of 15% by mass (more preferably 1% by mass to 15% by mass, and still more preferably 5% by mass to 15% by mass) is particularly preferable.
The acrylic resin in the above preferred form is advantageous in terms of the bending strength of the denture base material and the durability of the denture base (yield point strength of the compression test) as compared with, for example, polymethyl methacrylate (PMMA).

The polymer component in this embodiment may contain only 1 type of acrylic resin, and may contain 2 or more types.
Moreover, the polymer component in this embodiment may contain resin other than acrylic resin.
However, the content of the acrylic resin in the denture base material of the present embodiment (the total content in the case of two or more types) is 60% by mass or more based on the total amount of the denture base material. Preferably, it is 80% by mass or more, more preferably 90% by mass or more, preferably 95% by mass or more, and particularly preferably 99% by mass or more.

(Rubber)
The polymer component preferably further contains rubber.
When the polymer component in the present embodiment contains rubber, the impact strength of the denture base material is further improved, and the impact resistance (destructive weight of the falling ball test) when the denture base is used is further improved.
Examples of the rubber include acrylic rubber, butadiene rubber, butadiene-acrylic rubber, butadiene-styrene rubber, and silicone rubber.
When the polymer component in the present embodiment includes rubber, the type of rubber may be appropriately selected in consideration of physical properties. However, considering the balance of physical properties such as hardness and impact resistance, butadiene rubber or butadiene -Acrylic rubber is preferred.
In addition, when the polymer component in this embodiment contains rubber | gum, the rubber | gum contained in a polymer component may be only 1 type, or 2 or more types.

  The rubber preferably contains a graft polymer obtained by graft-polymerizing a thermoplastic resin component to a rubber-like polymer (preferably a rubber-like polymer having a crosslinked structure).

The thermoplastic resin component is not particularly limited as long as it is a monomer component that can be graft-polymerized with a rubber-like polymer. For example, an aromatic vinyl compound, a vinyl cyanide compound, a (meth) acrylic acid ester compound, (meta ) Acrylic acid compounds, N-substituted maleimide compounds, α, β-unsaturated carboxylic acid compounds, anhydrides thereof (for example, maleic anhydride, etc.), and the like. These monomer components may be used alone or in combination of two or more.
Here, “(meth) acrylic acid” is a concept including both acrylic acid and methacrylic acid (the same applies hereinafter).

Examples of the rubbery polymer include acrylic (co) polymers, butadiene (co) polymers, silicone polymers, and the like, and among them, butadiene (co) polymers are preferable. When the rubber-like polymer is a butadiene-based (co) polymer, the impact strength of the denture base material is further improved, and the impact resistance (destructive weight in the falling ball test) when the denture base is used is further improved.
Here, the “(co) polymer” is a concept including both a homopolymer and a copolymer (hereinafter the same).
That is, the rubber preferably contains a graft polymer obtained by graft polymerization of a thermoplastic resin component to a butadiene-based (co) polymer.

As the acrylic (co) polymer, a copolymer obtained by polymerizing a mixture containing one or more alkyl acrylates having 2 to 8 carbon atoms in the alkyl group and one or more polyfunctional monomers. Polymers are preferred.
If necessary, the above mixture may contain a copolymerizable monomer such as styrene; styrene derivatives such as α-methylstyrene and vinyltoluene; acrylonitrile; methyl methacrylate; and preferably styrene or styrene and a styrene derivative. May be included).
Examples of the alkyl acrylate ester having 2 to 8 carbon atoms in the alkyl group include ethyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate. Among these, n-butyl acrylate is more preferable. preferable.
Examples of the polyfunctional monomer include a known acrylic polyfunctional monomer, a known polyvalent aromatic vinyl monomer (for example, divinylbenzene), and the like.

The amount of the component constituting the acrylic (co) polymer is not particularly limited. As the acrylic (co) polymer, acrylic acid alkyl ester is 50.0% by mass to 99.9% by mass, polyfunctional monomer. A copolymer obtained by copolymerizing 0.1% by mass to 10% by mass of a polymer and 0% by mass to 49.9% by mass of a copolymerizable monomer is preferable.
A rubber obtained by graft polymerization of a thermoplastic resin component to such an acrylic (co) polymer is commercially available, for example, “Maybrene (registered trademark) W-450” manufactured by Mitsubishi Rayon Co., Ltd.

Examples of the butadiene-based (co) polymer include butadiene-n-butyl acrylate copolymer, butadiene-styrene copolymer, and the like.
The butadiene-based (co) polymer is obtained by copolymerizing 1,3-butadiene 5% by mass or more and 95% by mass or less of at least one monomer copolymerizable with 1,3-butadiene. The resulting copolymer is preferred.
Examples of the monomer copolymerizable with 1,3-butadiene include styrene, acrylonitrile, the alkyl alkyl acrylate ester having 2 to 8 carbon atoms described above, and the like.

In copolymerization of 1,3-butadiene and a monomer copolymerizable with 1,3-butadiene, a polyfunctional monomer may be used in combination.
Here, as a polyfunctional monomer, a well-known acrylic polyfunctional monomer, a well-known polyvalent aromatic vinyl monomer (for example, divinylbenzene), etc. are mentioned.

From the viewpoint of further improving the impact strength of the denture base material and further improving the impact resistance of the resulting denture base, the butadiene-based (co) polymer is a copolymer of butadiene and n-butyl acrylate. It is preferable that it is a butadiene-n-butyl acrylate copolymer obtained.
Rubbers obtained by graft polymerization of a thermoplastic resin component to such a butadiene-based (co) polymer are commercially available. For example, UMG ABS Co., Ltd. “MUX-60”, Kaneka Corporation “Kane Ace (registered) Trademark) M-521 ".

Examples of the silicone-based polymer include room temperature curable silicone rubber, thermosetting silicone rubber, and the like, and specific examples include dimethyl silicone rubber, vinyl methyl silicone rubber, methyl phenyl silicone rubber, and fluoro silicone rubber. It is done. A known silicone rubber may be used as the silicone polymer.
Rubber obtained by graft polymerization of a thermoplastic resin component to a silicone-based polymer is commercially available, for example, “Maybrene (registered trademark) S-2001” by Mitsubishi Rayon Co., Ltd.

The rubber is preferably rubber particles.
When the polymer component in the present embodiment includes rubber particles as rubber, the impact strength of the denture base material is further improved because the rubber particles are dispersed in the acrylic resin.
Examples of the rubber particles include rubber particles having a single layer structure, rubber particles having a multilayer structure, and the like.
The rubber particles having a multilayer structure include, for example, an inner layer made of a rubber-like polymer such as the above-mentioned acrylic (co) polymer, the above-mentioned butadiene-type (co) polymer, and the above-mentioned silicone polymer, And an outer layer made of a resin obtained by polymerizing the thermoplastic resin component described above.
Further, a rubbery polymer in which a small amount of a crosslinkable polyfunctional monomer is copolymerized may be used.
The resin obtained by polymerizing the thermoplastic resin component is preferably a polymer having a glass transition temperature of room temperature or higher.

  For example, acrylic rubber particles include a single layer structure made of a rubbery polymer mainly composed of methyl methacrylate, and an elastic resin layer mainly composed of an acrylic acid alkyl ester such as n-butyl acrylate. A multilayer structure having a thermoplastic resin layer mainly composed of methyl methacrylate around the inner layer may be used, and known acrylic rubber particles may be used.

The rubber particles are more preferably rubber particles that are graft polymers obtained by graft polymerization of a thermoplastic resin component to a rubber-like polymer (preferably a rubber-like polymer having a crosslinked structure).
As described above, examples of the rubbery polymer include acrylic (co) polymers, butadiene (co) polymers, silicone polymers, and the like, and among them, butadiene (co) polymers are preferable. .

  The average particle diameter of the rubber particles is preferably in the range of 0.03 μm to 2.0 μm. Thereby, the dispersion state of rubber particles can be suitably maintained in the denture base material. Rubber particles having such a particle size can be produced by an emulsion polymerization method.

When the polymer component in the present embodiment includes rubber, the rubber content is preferably 1% by mass or more and 10% by mass or less based on the total amount of the denture base material.
When the rubber content is 1% by mass or more, the impact strength of the denture base material is further improved, and the impact resistance (destructive weight in the falling ball test) when the denture base is used is further improved.
When the rubber content is 10% by mass or less, the bending strength of the denture base material is further improved, and the durability (yield point strength of the compression test) when the denture base is used is further improved. Furthermore, when the rubber content is 10% by mass or less, the bending elastic modulus of the denture base material is further improved, so that it is less likely to be deformed, and the workability in producing the denture base is further improved.
The upper limit of the rubber content is more preferably 8% by mass, and still more preferably 7% by mass.
The lower limit of the rubber content is preferably 1.5% by mass, and more preferably 2% by mass.

That is, the denture base material of the present embodiment contains a copolymer of methacrylic acid alkyl ester and methacrylic acid (preferably MMA-MAA copolymer) and a rubber as a polymer component, so that bending strength is increased. Of 110 MPa or more, a maximum stress intensity factor of 1.9 MPa · m ^1/2 or more, and a total fracture work of 900 J / m ² or more.

<Other ingredients>
The denture base material of this embodiment may contain other components as necessary.
Examples of other components include colorants.
There is no restriction | limiting in particular as a coloring agent, Although a pigment, dye, a colored fiber, etc. can be used, A pigment and dye are preferable and a pigment is especially preferable.
When the denture base material of this embodiment contains a colorant, the content of the colorant is preferably 0.001 to 0.20 parts by mass with respect to 100 parts by mass of the polymer component, and 0.001 parts by mass. Part to 0.15 part by mass is preferable, and 0.001 part to 0.10 part by mass is more preferable.
When the content of the colorant is 0.20 parts by mass or less, it is easier to achieve a bending strength of 110 MPa or more of the denture base material.

Further, the denture base material of the present embodiment may contain a material simulating a blood vessel, but the content of the material having a minor axis of 20 μm or more is 0. 0 parts by mass with respect to 100 parts by mass of the polymer component. The amount is preferably less than 001 parts by mass, and more preferably less than 0.0005 parts by mass. By adjusting the content of the material having a minor axis of 20 μm or more within the above range, the bending strength can be easily adjusted to 110 MPa or more.
In addition, when the said material is fibrous form, a short axis becomes an average diameter of a fiber.

  The denture base of this embodiment is obtained by cutting the uncolored denture base material as the denture base material of this embodiment to obtain an uncolored denture base, and then adding a colorant to the uncolored denture base. It may be obtained by coloring using. In this case, the denture base material of this embodiment does not necessarily need to contain a colorant.

In the denture base material of the present embodiment, the content of the polymer component is preferably 90% by mass or more based on the total amount of the denture base material. When the rubber particles are contained, it is preferably 90% by mass or more and 99% by mass or less, more preferably 92% by mass or more and 98.5% by mass or less, and 92% by mass or more and 98% by mass or less. It is particularly preferred.
When the content of the polymer component is 90% by mass or more, it is easy to achieve a bending strength of 110 MPa or more of the denture base material.

In addition, the size of the denture base material of the present embodiment is not particularly limited as long as the denture base can be obtained by cutting.
Further, the shape of the denture base material of the present embodiment is not particularly limited, but from the viewpoint of ease of cutting, a rectangular parallelepiped shape that is easy to fix to a cutting machine and that is easy to create a cutting program is preferable. A large rectangular parallelepiped shape capable of cutting a plurality at a time is more preferable.
For example, if the block has a rectangular parallelepiped shape of 230 mm × 190 mm × 30 mm, four complete denture bases can be obtained at a time, which is efficient. Further, from the viewpoint of effectively using the material, if the thickness of the rectangular parallelepiped is too thick, the portion to be discarded increases. Therefore, the thickness of the denture base material is preferably 20 mm to 40 mm.
In addition, from the viewpoint of cutting a plurality of denture base materials at a time, it is preferable that a changer device capable of automatically changing the denture base material is provided in the cutting machine.

Although there is no restriction | limiting in particular in the manufacturing method of the denture base material of this embodiment, The oligomer or prepolymer, or the mixture of an oligomer or prepolymer, and a monomer is used as a raw material, and it is several days-one week in the vicinity of polymerization temperature. A method of polymerizing slowly over a period of time is suitable. According to this manufacturing method, it is easy to manufacture a denture base material containing a polymer component having an Mw of 1,200,000 or more. That is, a denture base material having a bending strength of 110 MPa or more is easily obtained.
Furthermore, when the denture base material of the present embodiment contains the rubber particles, the rubber particles are mixed with the oligomer or prepolymer, or the oligomer or prepolymer added with a monomer, and then in the vicinity of the polymerization temperature. It is preferable to produce a denture base material by slowly polymerizing over several days to a week.
The raw material may contain other components (coloring agent, initiator, chain transfer agent, etc.) as necessary.
As the chain transfer agent, known compounds can be used without any limitation. For example, n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, 1,4-butanedithiol, 1,6-hexanedithiol, etc. Alkyl mercaptans; aromatic mercaptans; thioglycolic acid esters such as butanediol bisthioglycolate and hexanediol bisthioglycolate, ethylene glycol bisthiopropionate, butanediol bisthiopropionate, trimethylolpropane tris Mercaptopropionate esters such as thiopropionate and pentaerythritol tetrakisthiopropionate: terpinolene; α-styrene dimer and the like. The chain transfer agent may be only one type or two or more types.

[Denture base, base denture]
The denture base of this embodiment includes the denture base material of the above embodiment.
Therefore, the denture base of this embodiment is excellent in durability (yield point strength).
The denture base of this embodiment may be a denture base for a full denture (so-called full denture) or a denture base for a partial denture (so-called partial denture).
The denture base of the present embodiment may be a denture base for a maxillary denture (hereinafter also referred to as “maxillary denture base”), or a denture base for a lower denture (hereinafter referred to as “mandibular denture base”). Or a set of an upper denture base and a lower denture base.

Moreover, only a part of the denture base of the present embodiment may be configured by the denture base material of the present embodiment, or the entire denture base of the present embodiment may be configured by the denture base material of the present embodiment.
As an example of a denture base in which only a part is constituted by the denture base material of the present embodiment, at least a part of a resin portion of a denture base (so-called metal floor) including a metal portion and a resin portion is implemented. A denture base composed of a denture base material in a form; a denture base composed of only a resin portion of a denture base (so-called resin floor) made of a denture base material of the present embodiment; Can be mentioned.
An example of a denture base that is entirely constituted by the denture base material of the present embodiment is a denture base composed of only a resin portion.

  The denture base of the present embodiment is a denture base obtained by cutting a denture base material that is a block body having a thickness of 10 mm to 40 mm, which is a preferred form of the denture base material of the present embodiment. Particularly preferred.

The denture of this embodiment is provided with the denture base of the above embodiment and the artificial tooth fixed to the denture base.
Therefore, the denture of this embodiment is excellent in the durability (yield point strength) of the denture base.
The partial denture of this embodiment may be a partial denture or a complete denture. That is, the denture of this embodiment should just be provided with at least one artificial tooth.
Further, the denture of the present embodiment may be an upper denture, a lower denture, or a set of an upper denture and a lower denture.

  Examples of the material for the artificial teeth include acrylic resins. Examples of the acrylic resin are as described above. The artificial tooth may contain a filler or the like in addition to the acrylic resin.

FIG. 1 is a perspective view conceptually showing an example of a plate denture according to the present embodiment.
As shown in FIG. 1, an upper denture 10 that is an example of a denture of the present embodiment is fixed to an upper denture base 20 that is an example of a denture base of the present embodiment, and an upper denture base 20. Artificial teeth 12. In FIG. 1, only one of the plurality of artificial teeth is denoted by reference numeral 12.
The upper denture base 20 is produced by cutting the denture base material of the present embodiment. The maxillary denture 10 is produced by fixing the artificial tooth 12 to the maxillary denture base 20.

In addition, although illustration is abbreviate | omitted, the denture base is divided | segmented into the several part, Only the part may be produced by cutting the denture base material of this embodiment.
Further, the denture base and the denture of the present embodiment are not limited to the upper denture base and the upper denture base denture, and are the lower denture base and the lower base denture. Of course it is good.

[Method of manufacturing denture base, method of manufacturing denture base]
The manufacturing method of the denture base of this embodiment has the cutting process of cutting the denture base material of the said embodiment, and obtaining a denture base.
Cutting in the cutting process can be performed, for example, according to a cutting program created by a CAD (Computer Aided Design) / CAM (Computer Aided Manufacturing) system. The cutting can be performed using a CNC (Computer Numerical Control) cutting machine.
The cutting program can be created by a known method based on the three-dimensional shape in the patient's oral cavity. If a denture base suitable for the patient has already been created, three-dimensional (3D) data is obtained by optically scanning the denture base, and a cutting program is created based on the obtained 3D data. May be.

  The manufacturing method of the denture base of this embodiment may have other processes other than a cutting process as needed. Examples of other processes include a coloring process for coloring the denture base.

Moreover, the manufacturing method of the denture of this embodiment has the cutting process of obtaining a denture base by cutting the denture base material of the said embodiment, and the fixing process of fixing an artificial tooth to the said denture base. .
The preferable form of cutting in the cutting process is as described above.
The artificial tooth can be fixed in the fixing step by a usual method using an adhesive. As the adhesive, for example, dental adhesive resin cement “Super Bond” (registered trademark) manufactured by Sun Medical Co., Ltd. can be used.
Further, prior to fixing the artificial tooth to the denture base using the adhesive, at least one surface (adhesion surface) of the denture base and the artificial tooth may be subjected to a known surface treatment (easy adhesion treatment) in advance. Good.

  The manufacturing method of the denture of this embodiment may have other processes other than a cutting process and a fixing process as needed. Examples of other processes include a coloring process for coloring a denture base of a bed denture.

  Hereinafter, the embodiment of the present invention will be described more specifically by way of examples. However, the present embodiment is not limited to the following examples unless it exceeds the gist of the present invention.

[Example 1]
<Production of denture base material>
With respect to 93 parts by mass of prepolymerized methyl methacrylate syrup having fluidity at room temperature, liquid A [5 parts by mass of methacrylic acid monomer, 2 parts by mass of MUX-60 (manufactured by UMG ABS Co., Ltd .; rubber), 0 0.03 parts by mass of terpinolene (manufactured by Tokyo Chemical Industry Co., Ltd .; chain transfer agent) and 0.002 parts by mass of AIBN (2,2′-Azobis (isobutyronitrile); polymerization initiator) were added and mixed uniformly at room temperature. After adding 7.032 parts by mass and mixing at room temperature for homogenization, the solution was degassed. The defoamed composition was poured into a mold having a gasket interposed between two inorganic glasses, polymerized at 40 ° C. for 48 hours and at 120 ° C. for 5 hours, and a 30 mm thick rectangular resin block ( Denture base material) was prepared.
Here, MUX-60 (manufactured by UMG ABS Co., Ltd.) is a rubber obtained by graft polymerization of a thermoplastic resin component to a butadiene-based (co) polymer that is a rubber-like polymer having a crosslinked structure. .
The material of the obtained resin block is a mixture of methyl methacrylate-methacrylic acid copolymer (MMA-MAA copolymer) and rubber (MUX-60).

<Preparation of bending test specimen>
By cutting the resin block which is a denture base material obtained as described above, a rectangular parallelepiped bending test specimen having a size of 80 mm × 10 mm × 4 mm was obtained.

<3-point bending test (measurement of bending strength and flexural modulus)>
The test piece for bending test is subjected to a three-point bending test in accordance with JIS K7171 (2008) using an Intesco 5-spindle bending tester 2001-5, and the bending strength and bending elastic modulus are measured. did.
Here, the test speed was 2 mm / min, and the distance between fulcrums was 64 mm. The calculation method for the flexural modulus was the secant method.
The results are shown in Table 1 below.

<Preparation of Charpy impact test specimen>
A resin piece having the same size as that of the above test piece for bending test was prepared in the same manner, and a notch having a shape A defined in JIS K7111-1 (2012) was formed on the resin piece with a remaining width of 8.0 mm. One test piece for impact test (single-notched test piece) was obtained.

<Charpy impact test (impact strength measurement)>
For the above test piece for impact test, a Charpy impact test is performed under the condition of edgewise impact, using a thermostat impact tester DG-UB type manufactured by Toyo Seiki Seisakusho Co., Ltd. according to JIS K7111-1 (2012). Impact strength was measured.
Furthermore, in this test, after the pendulum collided with the test piece, the angle (°) at which the pendulum swung was measured. This angle indicates that the smaller the number, the greater the energy absorption at the time of collision, that is, the better the impact resistance.
The above results are shown in Table 1 below.

<Preparation of specimen for fracture toughness test>
By cutting the resin block that is the denture base material obtained above, a resin piece having a length of 39 mm, a height of 8 mm, and a width of 4 mm is produced, and the resin piece is defined in JIS T6501 (2012). A notch was provided to obtain a fracture toughness test specimen (notched specimen).

<Fracture toughness test (measurement of maximum stress intensity factor and total fracture work)>
Using the universal testing machine (model number: 210X type) manufactured by Intesco Corporation, the fracture toughness test specimen is subjected to a fracture toughness test by a bending test in accordance with JIS T6501 (2012). Measured work. The test speed was 1 mm / min, and the distance between fulcrums was 32 mm.
The results are shown in Table 1 below.

<Molecular weight average molecular weight (Mw), number average molecular weight (Mn), molecular weight distribution (Mw / Mn)>
For the polymer component in the resin block, the weight average molecular weight (Mw), the number average molecular weight (Mn), and the molecular weight distribution (Mw / Mn) were measured according to the GPC measurement method described above.
The results are shown in Table 1 below.

<Preparation of denture base for compression test>
3D data of the maxillary denture base prepared in Comparative Example 1 described later was acquired using a 3D scanner.
From this 3D data, using CAD / CAM software, a cutting program for cutting the resin block as a denture base material to obtain an upper denture base was created.
In accordance with this cutting program, the above resin block was cut using a CNC cutting machine to obtain an upper denture base.

<Compression test of denture base (measurement of yield point strength)>
Using the universal material testing machine AG-100kNX with a thermostatic chamber manufactured by Shimadzu Corporation, the above denture base compression test (measurement of yield point strength) was performed.
Specifically, the upper denture base is placed on a test table so that the mucosal surface (the surface in contact with the ridge and palate) is on the upper side, and then the central portion of the upper denture base is a circle having a diameter of 20 mm. It compressed with the speed | rate of 1 mm / min with the bottom face of the column-shaped stick | rod (material: carbon steel S45C).
In the above compression, the displacement and strength were recorded, and the maximum point of strength was taken as the yield point strength.
The results are shown in Table 1 below.

<Production of denture base for falling ball test>
Using CAD software, thin-walled 3D data in which the thickness of the upper palate portion of the upper denture 3D data acquired at the time of preparation of the denture base for compression test described above was reduced by 1.2 mm was created.
From this thinned 3D data, a cutting program for obtaining the thinned denture base by cutting the resin block as the denture base material using CAD / CAM software was created.
According to this cutting program, the resin block was cut using a CNC cutting machine to obtain a thinned denture base for maxilla.

<Falling ball test of denture base (measurement of breaking weight)>
A falling ball test (measurement of breaking weight) of the thinned denture base for maxilla was performed.
Specifically, the above-mentioned thinned denture base is placed on the test table so that the mucosal surface (the surface in contact with the ridge and palate) is on the upper side, and then collides with the center of this thinned denture base As described above, the steel balls were dropped from a light weight in order from a height of 100 cm, and the weight when the denture base was cracked was recorded, and this was taken as the breaking weight.
The weights of the dropped steel balls were 6.9 g, 8.4 g, 9.0 g, 10.0 g, 10.0 g, 11.2 g, 11.9 g, 13.8 g, 14.0 g, 16.3 g, 16 0.7 g, 18.9 g, 20.0 g, 21.7 g, 23.8 g, 24.8 g, 28.0 g, 28.2 g, 33.2 g, 45.5 g.
The results are shown in Table 1 below.

<Evaluation of cutting workability of denture base material>
In the process from cutting the resin block as a denture base material to obtaining a denture base, the machinability was evaluated based on the following evaluation criteria.
The results are shown in Table 1 below.

-Evaluation criteria for machinability-
A: Cracking and chipping did not occur during cutting, and cutting workability was good.
B: At least one of cracking and chipping occurred during cutting, and cutting workability was poor.

[Example 2]
In Example 1, the amount of methyl methacrylate syrup was changed to 88 parts by mass, and the same operation as in Example 1 was performed except that the amount of methacrylic acid monomer was changed to 10 parts by mass. A resin block (material for denture base) was prepared.
The material of the obtained resin block is a mixture of methyl methacrylate-methacrylic acid copolymer (MMA-MAA copolymer) and rubber (MUX-60).

Example 3
In Example 1, the same operation as in Example 1 was performed except that 2 parts by mass of MUX-60 was changed to 2 parts by mass of Kaneace (registered trademark) M-521 (manufactured by Kaneka Corporation; rubber). A rectangular parallelepiped resin block (material for denture base) having a thickness of 30 mm was produced.
Here, “M-521” is a rubber obtained by graft polymerization of a thermoplastic resin component to a butadiene-based (co) polymer that is a rubber-like polymer having a crosslinked structure.
The material of the obtained resin block is a mixture of methyl methacrylate-methacrylic acid copolymer (MMA-MAA copolymer) and rubber (M-521).

[Comparative Example 1]
In Example 1, a test piece for bending test, a test piece for impact test piece, a test piece for fracture toughness test, and a denture base for compression test (upper denture base) were prepared as follows. The same operation as Example 1 was performed except having changed into the test piece, the test piece for impact test pieces, the test piece for fracture toughness tests, and the denture base for maxilla.
The results are shown in Table 2.

<Preparation of bending test specimen>
(Preparation of a plaster mold for bending test specimens)
First, a flask for preparing a denture (a set of a flask lower mold and a flask upper mold) was prepared.
Next, a rectangular parallelepiped plate having a length, width and thickness slightly larger than the size of 80 mm (length) × 10 mm (width) × 4 mm (thickness) was cut out from the resin block. A denture base resin separating agent NEW ACROSEP (manufactured by GC Corporation) was applied to the entire machined plate.
Next, a plaster dental blaster (manufactured by Noritake Co., Ltd.) mixed with a predetermined amount of water was poured into the lower mold of the flask until it was filled and left for a while. At the stage where the gypsum has hardened, the center part of the gypsum was pressed to form a recess having a size enough to accommodate the above plate.
After the plaster completely hardened, dental hard plaster New Diamond Stone Natural Gray (manufactured by Morita) mixed with a predetermined amount of water was poured into the depression and left for a while. When the hard plaster had hardened, the plate coated with the separating agent was buried in the hard plaster so that only the upper surface of the plate was exposed, and the surface of the hard plaster was smoothed.
After the hard plaster was completely hardened, the separating agent was applied to the entire surface of the plaster containing the hard plaster.
Next, after attaching the flask upper mold on the flask lower mold, hard plaster new diamond stone natural gray mixed with a predetermined amount of water was placed so as to hide the above plate.
Next, a gypsum dental blaster mixed with a fixed amount of water was poured to the extent that it overflowed from the dental flask, and then the cap was capped. After the gypsum solidified, the lower flask type and the upper flask type were separated, and the plate was removed.
As described above, a plaster mold (a set of a plaster mold upper mold and a plaster mold lower mold) for a test specimen for a bending test was obtained in the flask for producing a denture.
Here, the gypsum mold upper mold was produced in the flask upper mold, and the gypsum mold lower mold was produced in the flask lower mold. The plaster mold upper mold and the plaster mold lower mold are configured such that when the two are combined, a space in the shape of the above plate is formed.
Subsequently, the said separating agent was apply | coated to the whole gypsum surface of a gypsum type | mold upper mold | type and a gypsum mold | type lower mold | type.

(Preparation of test specimen for bending test)
Using a denture preparation flask in which a plaster mold of the above bending test specimen was prepared, a plate made of PMMA resin was obtained, and the resulting plate was polished to be a test for bending test of 80 mm × 10 mm × 4 mm size. A piece was made. Detailed operations are shown below.
First, floor resin material Akron Clear No. 5 (manufactured by GC Corporation) was prepared, and 6 g of the powder material and 2.5 g of the liquid material were weighed into a container and mixed. When the obtained mixture was allowed to stand for a while to become a bowl-like shape, the bowl-like mixture was placed in a large amount on a gypsum-type lower mold cavity formed in the flask lower mold to adjust the shape.
Next, an upper flask mold in which a gypsum mold upper mold was produced was placed on the lower mold of the flask, and pressure was applied with a press. Next, the upper mold of the flask was removed, the resin material for the bowl-shaped floor protruding from the depression was removed, the upper mold of the flask was placed again, and pressure was applied with a press. Thereafter, the flask (a flask in which the upper flask mold and the lower flask mold were combined) was fixed with a flask clamp.
The flask was placed in a pan containing water and heated slowly in a gas range to 100 ° C. over 30 minutes. After reaching 100 ° C. for 30 to 40 minutes, the heating was terminated and the mixture was cooled to 30 ° C.
Next, the flask lower mold and the flask upper mold were separated, then the plaster mold was broken, and the finished plate (PMMA resin) was taken out. The taken out plate was polished to obtain a rectangular parallelepiped plate having a size of 80 mm × 10 mm × 4 mm, and this was used as a test piece for bending test (material is PMMA resin).

<Preparation of impact test specimen>
A resin piece having the same size as that of the test piece for bending test obtained above was prepared in the same manner, and a notch of shape A was provided on this resin piece in the same manner as the test piece for impact test piece of Example 1, A test piece for a test piece was obtained.

<Preparation of specimen for fracture toughness test>
By cutting the resin block, which is the denture base material obtained above, a resin piece having a length of 39 mm, a height of 8 mm, and a width of 4 mm was produced. The test piece for fracture toughness test of Example 1 was applied to this resin piece. A notch was provided in the same manner as described above to obtain a specimen for fracture toughness test (notched specimen).

<Preparation of denture base for compression test>
(Production of wax-made dentures)
A rough impression of the patient's upper and lower jaws was taken, a tray having a shape suitable for the patient was made from the rough impression, and a precise impression of the patient was taken using the obtained tray. Based on the precise impressions obtained, separate upper and lower gypsum models that fit the patient were made.
Next, an occlusal floor made of a base plate and a wax was produced to connect the upper and lower sides of the plaster model to reproduce the upper and lower occlusions.
Next, look at the patient's oral cavity and observe the jaw movement, reproduce the jaw movement on the above occlusal floor, obtain the occlusal state three-dimensionally, determine the occlusal position, and make a wax denture base (A set of an upper denture base and a lower denture base) was prepared.
By placing artificial teeth pre-applied with a wax pattern separating agent SEP (manufactured by Matsukaze Co., Ltd.) on the wax denture base thus obtained, and then performing trial adjustment and adjustment, wax dentures (maxillary dentures and A set with a lower denture was prepared.

(Preparation of plaster mold for denture base)
First, a denture preparation flask composed of a flask lower mold and a flask upper mold was prepared.
Furthermore, the artificial tooth was removed from the wax denture to prepare a wax denture base.
Next, the wax denture base and the above-mentioned gypsum model were combined and placed in a lower mold of the flask. A gypsum dental blaster mixed with a predetermined amount of water was poured into the cup and allowed to stand for a while. After the gypsum set, the above separating agent was dropped on the gypsum and applied to the whole using a brush. Thereafter, the upper mold of the flask was placed on the lower mold of the flask, and the gypsum was poured to the full frame, and the lid was covered and left until the gypsum was completely hardened.
After the gypsum set, the upper mold and the lower mold of the flask were separated, warmed with hot water to dissolve the wax, and the base plate was removed.
Thus, a plaster mold for a denture base composed of an upper mold for a plaster mold and a lower mold for a plaster mold was obtained.
Here, the gypsum mold upper mold was produced in the flask upper mold, and the gypsum mold lower mold was produced in the flask lower mold. When the two types of the upper plaster mold and the lower plaster mold are combined, a space in the shape of the denture base made of wax is formed.
Subsequently, the said separating agent was apply | coated to the whole gypsum surface of a gypsum type | mold upper mold | type and a gypsum mold | type lower mold | type.

(Preparation of denture base for compression test)
In the preparation of the test piece for bending test of Comparative Example 1, the denture base was the same as the preparation of the test piece for bending test except that the gypsum mold of the test specimen for bending test was changed to the gypsum mold for denture base. (Set of denture base for maxilla and denture base for mandible; materials are both PMMA resin).
Among these, an upper denture base was used for a compression test (measurement of yield point strength).

[Comparative Example 2]
In Comparative Example 1, Akron Clear No. 5 (manufactured by GC Corporation), Akron Live Pink No. The same operation as in Comparative Example 1 was performed except that it was changed to 8 (manufactured by GC Corporation). The denture base material and the denture base material are PMMA resins.
The results are shown in Table 1 below.

[Comparative Example 3]
In Comparative Example 1, Akron Clear No. 5 (manufactured by GC Corporation), Para Express Ultra Pink Live No. The same operation as in Comparative Example 1 was performed except that the change was made to 34 (manufactured by Heraeus Kultzer). The denture base material and the denture base material are PMMA resins.
The results are shown in Table 1 below.

[Comparative Example 4]
In Comparative Example 1, Akron Clear No. 5 (made by GC Corporation) 8 (manufactured by GC Corporation). The same operation as in Comparative Example 1 was performed, except that the mixture of powder material / liquid material 8 (powder material / liquid material) was mixed at 100/50 (g / ml). Laxon Live Pink No. Reference numeral 8 denotes a PMMA denture base resin that satisfies the additional required characteristics (maximum stress intensity factor and total fracture work) defined in JIS T6501. That is, the denture base material and the denture base material are PMMA resins. The results are shown in Table 1 below.
Further, in Comparative Example 4, a denture base material and a falling ball test denture base (thinned denture base for thinning maxilla) were prepared as described below, and a falling ball test was performed.

<Production of denture base material>
After producing the denture base for falling ball test in Example 1, a resin block with a hole that is slightly larger than the denture base for falling ball test is prepared in the center, and on a smooth iron plate slightly larger than this resin block. I put it.
Next, Laxon Live Pink No. The powder material and liquid material of 8 were weighed into a container, and the ratio of the powder material to the liquid material (powder material / liquid material) was mixed at 100/50 (g / ml). When the obtained mixture was left standing for a while to form a bowl, the bowl-like mixture was charged into the hole portion of the resin block placed on the iron plate so as to fill the hole portion. An iron plate of the same size as the above iron plate was placed on top, and pressure was applied with a press. Then, it fixed with the clamp.
The resin block fixed with this clamp was put in a pan containing water and slowly heated to 100 ° C. over 30 minutes in a gas range. After reaching 100 ° C. for 30 to 40 minutes, the heating was terminated and the mixture was cooled to 30 ° C.
Next, remove the clamp and the upper and lower iron plates, and Laxon Live Pink No. A rectangular parallelepiped resin block (denture base material) having a thickness of 8 mm and containing 8 cured products was produced.

<Production of denture base for falling ball test>
According to the cutting program created from the thinned 3D data created in Example 1, the resin block was cut using a CNC cutting machine to obtain a thinned denture base for the maxilla.

<Falling ball test of denture base (measurement of breaking weight)>
The falling ball test (measurement of breaking weight) of the above thinned denture base for maxilla was performed in the same manner as in Example 1.
The results are shown in Table 1 below.

[Comparative Example 5]
In Comparative Example 1, Akron Clear No. 5 (made by GC Corporation) Pro Impact Live Pink No. 8 (made by GC Corporation) and its Pro Impact Live Pink No. The same operation as in Comparative Example 1 was performed, except that the mixture of powder material / liquid material 8 (powder material / liquid material) was mixed at 100/50 (g / ml). In addition, Pro Impact Live Pink No. Reference numeral 8 denotes a PMMA denture base resin that satisfies the additional required characteristics (maximum stress intensity factor and total fracture work) defined in JIS T6501. That is, the denture base material and the denture base material are PMMA resins.
The results are shown in Table 1 below.

-Description of Table 1-
• “Angle” in Charpy impact test refers to the angle (°) at which the pendulum swings after the pendulum collides with the test piece.
-"Wt%" shows the mass% with respect to the whole quantity of the resin block (denture base material).

As shown in Table 1, an implementation satisfying that the bending strength is 110 MPa or more and that the maximum stress intensity factor is 1.9 MPa · m ^1/2 or more and the total fracture work is 900 J / m ² or more. The denture base materials of Examples 1 to 3 were excellent in hardness (flexural modulus). Furthermore, the denture bases of Examples 1 to 3 manufactured using this denture base material were excellent in durability (yield point strength). Moreover, since the denture base materials of Examples 1 to 3 all had high impact strength, they were excellent in impact resistance. These denture base materials were also excellent in cutting workability.
In contrast, the denture base materials of Comparative Examples 1 to 3 having a bending strength of less than 110 MPa and a maximum stress intensity factor of less than 1.9 MPa · m ^1/2 or a total fracture work of less than 900 J / m ² It can be seen that the hardness (flexural modulus) is low and the impact resistance (impact strength) is low. Moreover, it turns out that the denture base material of the comparative examples 4 and 5 whose bending strength is less than 110 MPa has low hardness (bending elastic modulus). Moreover, it turns out that the denture base of Comparative Examples 1-5 produced using these denture base materials has low durability (yield point strength).

[Reference Example 1]
As Reference Example 1, an example of a method for estimating the fracture toughness of a denture base material used as a raw material of the denture base based on the denture base is shown.
It is practically difficult to cut out a test piece having a length of 39 mm, a height of 8 mm, and a width of 4 mm from the denture base.
However, the fracture toughness of the denture base material used as the raw material for the denture base can be estimated by performing the following micro fracture toughness test on the denture base.

-Micro fracture toughness test-
A minute test piece having a length of 18.5 mm, a height of 4 mm, and a width of 2 mm is cut out from the denture base, and the depth of the cut is 1.5 mm and the depth of the notch is 50 to 200 μm. The fracture toughness test was carried out under the same conditions as the fracture toughness test conditions for the denture base material, except that the immersion in water was not performed and the distance between the fulcrums was 16 mm. This fracture toughness test is referred to as “micro fracture toughness test”, and the obtained maximum stress intensity factor and total fracture work are referred to as “micro maximum stress intensity factor” and “micro total fracture work”, respectively.

For each denture base of Examples 1, 2, and 3, the minute maximum stress intensity factor and minute total fracture work were measured.
The obtained results are shown in Table 2 below.
Table 2 below also shows the maximum stress intensity factor and total fracture work of the denture base material of each example.

FIG. 2 is a graph showing the relationship between the minute maximum stress intensity factor of the denture base and the maximum stress intensity factor of the denture base material created based on the results of Table 2.
FIG. 3 is a graph showing the relationship between the minute total destructive work of the denture base and the total destructive work of the denture base material, created based on the results of Table 2.
As shown in FIGS. 2 and 3, it was found that the maximum stress intensity factor and the total fracture work of the denture base material are directly proportional to the micro maximum stress intensity coefficient and the micro total fracture work of the denture base, respectively. Therefore, it was found that the maximum stress intensity factor and the total fracture work of the denture base material used as the raw material of the denture base can be estimated by measuring the micro maximum stress intensity factor and the micro total fracture work of the denture base.
From the viewpoint of improving durability (yield point strength in compression test), for example, the micro maximum stress intensity factor of the denture base is preferably 1.6 MPa · m ^1/2 or more, and the micro total fracture work is 340 MPa · m. It is preferable that it is ^1/2 or more.

[Reference Example 2]
As Reference Example 2, an example of a method for estimating the bending strength of a denture base material used as a raw material of the denture base based on the denture base will be described.
It is practically difficult to cut out a test piece having a length of 80 mm, a width of 10 mm, and a thickness of 4 mm from the denture base.
However, the bending strength of the denture base material used as the raw material for the denture base can be estimated by performing the following microbending test on the denture base.

-Micro bending test-
A fine test piece having a length of 25 mm, a width of 2 mm, and a thickness of 2 mm is cut out from the denture base, and the obtained fine test piece is subjected to a three-point bending test at a test speed of 1 mm / min and a distance between fulcrums of 20 mm. . This three-point bending test is referred to as “micro bending test”, and the obtained bending strength is referred to as “micro bending strength”.
Among the measurement conditions of the “microbending test”, conditions other than the above conditions are the same as the three-point bending test conditions for the denture base material.
A “microbending test” is measured for a plurality of denture bases (for example, 10 samples), and a graph showing the relationship between the microbending strength of the denture base and the impact strength of the denture base material is created. From this graph, the bending strength of the denture base material used as the raw material of the denture base can be estimated by measuring the micro bending strength of the denture base.

10 Maxillary denture (bed denture)
12 Artificial teeth 20 Denture base for maxilla (denture base)

Claims (18)

Contains polymer components including acrylic resins,
Bending strength measured by a three-point bending test under the conditions of a test speed of 2 mm / min and a fulcrum distance of 64 mm in accordance with JIS K7171 (2008) when a test piece having a length of 80 mm, a width of 10 mm, and a thickness of 4 mm is used. Is 110 MPa or more,
Maximum stress expansion measured by a fracture toughness test by a bending test under a test speed of 1 mm / min in accordance with JIS T6501 (2012) when a notched specimen having a length of 39 mm, a height of 8 mm, and a width of 4 mm is used. A denture base material having a coefficient of 1.9 MPa · m ^1/2 or more and a total fracture work of 900 J / m ² or more.   The denture base material according to claim 1, wherein the bending strength is 200 MPa or less. The denture base material according to claim 1, wherein the maximum stress intensity factor is 3.5 MPa · m ^1/2 or less, and the total fracture work is 2500 J / m ² or less. When a test piece with a single notch having a length of 80 mm, a width of 10 mm, a remaining width of 8 mm, and a thickness of 4 mm provided with a notch of shape A defined in JIS K7111-1 (2012) is JIS K7111-1 ( The denture base according to any one of claims 1 to 3, wherein an impact strength measured by a Charpy impact test under an edgewise impact condition in accordance with 2012) is 1.6 kJ / m ² or more. Materials.   The denture base material according to any one of claims 1 to 4, wherein the polymer component has a weight average molecular weight of 1,200,000 or more.   The denture base material according to any one of claims 1 to 5, wherein the polymer component further contains rubber.   The denture base material according to claim 6, wherein the rubber includes a graft polymer obtained by graft polymerization of a thermoplastic resin component on a rubbery polymer having a crosslinked structure.   The denture base material according to claim 6 or 7, wherein the rubber includes a graft polymer obtained by graft polymerization of a thermoplastic resin component to a butadiene-based (co) polymer.   The denture base material according to any one of claims 6 to 8, wherein a content of the rubber is 1% by mass or more and 10% by mass or less based on a total amount of the denture base material.   The denture base material according to any one of claims 1 to 9, wherein a content of the acrylic resin is 90% by mass or more based on a total amount of the denture base material.   The denture base material according to any one of claims 1 to 10, wherein the acrylic resin is a polymer containing 95 mass% or more of a structural unit derived from a monofunctional acrylic monomer.   The denture base material according to claim 11, wherein the monofunctional acrylic monomer is at least one monomer selected from the group consisting of methacrylic acid and alkyl methacrylate. The monofunctional acrylic monomer consists of methacrylic acid and alkyl methacrylate.
The denture base material according to claim 11, wherein an amount of the methacrylic acid with respect to a total amount of the methacrylic acid and the alkyl methacrylate is 0.1% by mass or more and 15% by mass or less.   The denture base material according to any one of claims 1 to 13, wherein the acrylic resin is a copolymer of methacrylic acid and methyl methacrylate.   A denture base comprising the denture base material according to any one of claims 1 to 14.   A denture having a denture base according to claim 15 and an artificial tooth fixed to the denture base.   The manufacturing method of a denture base which has the cutting process which cuts the denture base material of any one of Claims 1-14, and obtains a denture base. A cutting process for obtaining a denture base by cutting the denture base material according to any one of claims 1 to 14,
A fixing step of fixing artificial teeth to the denture base;
The manufacturing method of the denture which has this.