JP2017048121A - Dental composition, dental mill blank, dental member and method for producing the same, denture base and method for producing the same, and denture and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dental composition which makes it possible to produce a dental member excellent in flexural strength, flexural modulus, toughness, and surface smoothness.SOLUTION: A dental composition comprises at least one thermoplastic resin (A) selected from the group consisting of polyamide and polyester, and inorganic filler (B) with average thickness of 0.1 μm to 160 μm and average aspect ratio of 2.0 to 65.SELECTED DRAWING: None

Description

  The present invention relates to a dental composition, a dental mill blank, a dental member and a manufacturing method thereof, a denture base and a manufacturing method thereof, and a denture base and a manufacturing method thereof.

  Conventionally, metal members have been used as dental members such as dental prostheses (dental restorations) and denture members. In recent years, from the viewpoint of aesthetics, weight, feeling of wearing, prevention of metal allergy, etc., it has been studied to use a resin material or a composition of a resin material and an inorganic material instead of metal as a material for a dental member. ing.

For example, as a composition used for a dental restoration, the Mohs hardness is 3.0 to 4.5, the inorganic compound is a particle having an average size of less than 15 μm, and the refractive index is 1.53 to 1.56. A composition comprising a methacrylate resin having a Mohs hardness of 2.0 to 4.0 during curing is known (see, for example, Patent Document 1).
In addition, in an organic-inorganic composite material used for manufacturing dental materials and the like, (A) in 100 parts by mass of a thermoplastic resin containing at least one selected from a polyaryl ketone resin and a polysulfone resin as a main component, (B) 60 to 300 parts by mass of the inorganic particle mixture is dispersed, the particle content in the inorganic particle mixture in the range of 200 to 700 nm is 25% by volume or more, and the particle size is 40 to 100 nm. An organic-inorganic composite material having a content of particles in the range of 10 vol% or more is known (see, for example, Patent Document 2).
Moreover, it consists of hardened | cured material of a curable composition containing polymerizable monomers (A), such as (meth) acrylic acid ester, and the spherical inorganic filler (B) whose average primary particle diameter is 0.1 micrometer or more and less than 1 micrometer. A dental mill blank is known (for example, see Patent Document 3).
Further, in the bracket made of a synthetic resin main body having a slot for guiding or fixing the archwire, the synthetic resin main body is a member formed of a polyamide material and having a mounting surface on a tooth surface, and the polyamide Is a transparent member that transmits light, and a polyamide orthodontic bracket having a specific chemical structure is known (see, for example, Patent Document 4).
Also, a dental molded product having a predetermined shape used in the oral cavity, the molded product comprising a dicarboxylic acid component containing a terephthalic acid residue, and 2,2,4,4-tetramethyl-1 A dental molded body is known which is molded from a polyester resin comprising a 1,3-cyclobutanediol residue and a glycol component containing a 1,4-cyclohexanedimethanol residue (see, for example, Patent Document 5). .

U.S. Pat. No. 4,020,557 JP 2013-144778 A International Publication No. 2012/042911 International Publication No. 2012/020810 International Publication No. 2013/061462

The dental member is required to have bending strength and bending elastic modulus in order to withstand the operation of mastication. On the other hand, dental members are also required toughness from the viewpoint of ease of mounting in the oral cavity and ease of desorption from the oral cavity.
However, dental members containing a methacrylate resin may lack toughness.
Further, a dental member containing polyamide or polyester and not containing a filler may have insufficient bending strength and bending elastic modulus. Moreover, even if it is a dental member containing a polyamide or polyester and containing a filler, the bending strength and the bending elastic modulus may be insufficient depending on the size and shape of the filler.

The dental member is also required to have a smooth surface on the surface of the dental member from the viewpoint of suppression of plaque adhesion and the feeling of wearing.
However, when the dental member contains a filler, the smoothness of the surface of the dental member may be impaired depending on the size and shape of the filler.

Therefore, the objective of this invention is providing the dental composition and dental mill blank which can manufacture the dental member excellent in bending strength, bending elastic modulus, toughness, and surface smoothness.
Another object of the present invention is to provide a dental member excellent in bending strength, flexural modulus, toughness, and surface smoothness, and a manufacturing method thereof, a denture base provided with the dental member, a manufacturing method thereof, and the dental It is providing the base denture provided with the member, and its manufacturing method.

Means for solving the above problems are as follows.
<1> at least one thermoplastic resin (A) selected from the group consisting of polyamide and polyester;
An inorganic filler (B) having an average thickness of 0.1 to 160 μm and an average aspect ratio of 2.0 to 65;
A dental composition containing
<2> Dental composition as described in <1> whose glass transition point of the said thermoplastic resin (A) is 50 to 250 degreeC.
<3> The dental composition according to <1> or <2>, wherein the thermoplastic resin (A) includes a structural unit having at least one ring selected from the group consisting of an aromatic ring and an aliphatic ring. .
<4> The dental composition according to any one of <1> to <3>, wherein the thermoplastic resin (A) includes a polyamide having an amide bond concentration of 17% by mass to 37% by mass.
<5> The dental composition according to any one of <1> to <4>, wherein the thermoplastic resin (A) includes an amorphous resin.
<6> The content of the inorganic filler (B) is 5% by mass to 50% by mass with respect to the total content of the thermoplastic resin (A) and the inorganic filler (B). The dental composition as described in any one of <5>.

<7> A dental mill blank containing the dental composition according to any one of <1> to <6>.
<8> The dental mill blank according to <7>, which is used for producing a dental member selected from an inlay, an onlay, a crown, a bridge, a clasp, and a denture frame by cutting.
<9> The dental mill blank according to <7> or <8>, wherein the thickness is 10 mm to 30 mm.

<10> A dental member comprising the dental composition according to any one of <1> to <6>.
<11> A denture base comprising the dental member according to <10> and a denture base member fixed to the dental member.
<12> A denture having the denture base according to <11> and an artificial tooth fixed to the denture base member of the denture base of the denture base.
<13> A method for producing a dental member having a cutting step of cutting a dental mill blank according to any one of <7> to <9> to obtain a dental member.
<14> A cutting step of cutting a dental mill blank according to any one of <7> to <9> to obtain a dental member;
A build-up step of forming a denture base member fixed to the dental member by building a resin material on the dental member;
The manufacturing method of the denture base which has this.
<15> A cutting step of cutting the dental mill blank according to any one of <7> to <9> to obtain a dental member;
A build-up step of forming a denture base member fixed to the dental member by building a resin material on the dental member;
An artificial tooth fixing step of fixing artificial teeth to the denture base member;
The manufacturing method of the denture which has this.

ADVANTAGE OF THE INVENTION According to this invention, the dental composition and dental mill blank which can manufacture the dental member excellent in bending strength, a bending elastic modulus, toughness, and surface smoothness are provided.
Further, according to the present invention, a dental member excellent in bending strength, flexural modulus, toughness, and surface smoothness, and a manufacturing method thereof, a denture base provided with the dental member, a manufacturing method thereof, and the dental A denture with a member and a method for manufacturing the same are provided.

It is a graph which shows the relationship between the immersion time (Immersed Time) which immersed the polyamide in water in Reference Example 1, and the water absorption rate (Water Sorption) of a polyamide. It is a graph which shows the relationship between the density | concentration (Concentration of Amide-bonds) of the polyamide produced based on the graph of FIG. 1, and the water absorption rate (Water Sorption) of polyamide.

Hereinafter, embodiments of the present invention will be described in detail.
In this 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. For example, “numerical value A to numerical value B” has the same meaning as “numerical value A to numerical value B”.
Further, in this specification, “dental member” is used in the oral cavity such as a dental prosthesis (inlay, onlay, crown, bridge, etc.), a denture member (clasp, denture frame, etc.). Refers to all parts.
Moreover, in this specification, "dental mill blank" refers to the raw material for manufacturing a dental member by cutting.
Moreover, in this specification, a "dental composition" refers to the composition used as a raw material of a dental member or a dental mill blank.

[Dental composition]
The dental composition of the present embodiment (hereinafter also referred to as “the composition of the present embodiment”) has at least one thermoplastic resin (A) selected from the group consisting of polyamide and polyester, and an average thickness of 0. And an inorganic filler (B) having an average aspect ratio of 2.0 to 65 and an average aspect ratio of 1 to 160 μm. The composition of this embodiment may contain the other component as needed.
According to the composition of this embodiment, a dental member excellent in bending strength, bending elastic modulus, toughness, and surface smoothness can be produced.

  Specifically, the composition of the present embodiment contains the thermoplastic resin (A), so that, for example, a composition containing a methacrylate resin instead of the thermoplastic resin (A) is used. Toughness is improved.

Moreover, in the composition of this embodiment, the said inorganic filler (B) contributes to the improvement of the bending strength and bending elastic modulus of a dental member. Furthermore, by selecting the inorganic filler (B), a decrease in the smoothness of the surface of the dental member, which may occur when the inorganic filler is contained, is suppressed.
More specifically, when the average aspect ratio of the inorganic filler (B) is 2.0 or more, the bending strength of the dental member is higher than that when the average aspect ratio of the inorganic filler is less than 2.0. And the flexural modulus is improved.
In addition, since the average aspect ratio of the inorganic filler (B) is 65 or less, a decrease in the smoothness of the surface of the dental member is suppressed as compared with the case where the average aspect ratio of the inorganic filler is more than 65. The In particular, when the average aspect ratio of the inorganic filler (B) is 65 or less, the smoothness of the polished surface when the dental member is polished is also excellent.
The superior smoothness of the surface of the dental member is advantageous, for example, from the viewpoint of suppressing the adhesion of plaque to the dental member and improving the wearing feeling of the dental member on the oral cavity.
When the average thickness of the inorganic filler (B) is 160 μm or less, a decrease in the smoothness of the surface of the dental member is suppressed as compared with the case where the average thickness is more than 160 μm.
When the average thickness of the inorganic filler (B) is 0.1 μm or more, the bending strength and the bending elastic modulus of the dental member are improved as compared with the case where the average thickness is less than 0.1 μm.

The toughness of the dental member can be confirmed, for example, by measuring the impact strength (for example, Izod impact strength) of the dental member.
The smoothness of the surface of the dental member can be confirmed, for example, by measuring the surface roughness (for example, surface roughness Ra) of the dental member.

Moreover, according to the composition of this embodiment, in addition to the effects described above, the following effects can also be expected.
That is, the composition of the present embodiment contains the thermoplastic resin (A), so that, for example, PEEK (polyether ether ketone) is contained instead of the thermoplastic resin (A). Excellent transparency and aesthetics, and excellent manufacturing cost.
Moreover, the composition of this embodiment contains the said thermoplastic resin (A), and it is easy to shape | mold compared with the case where it replaces with the said thermoplastic resin (A) and contains a thermosetting resin. is there.
Moreover, the composition of this embodiment is excellent also in the dimensional accuracy at the time of cutting a dental mill blank by containing the said inorganic filler (B). That is, since heat at the time of cutting can be released by the inorganic filler (B), thermal deformation of the dental member or dental mill blank due to cutting is suppressed.
Moreover, when the composition of this embodiment contains the said inorganic filler (B), when cutting a dental mill blank, a composition is hard to get entangled with a cutting member (a drill etc.).

In the present specification, the average thickness of the inorganic filler (B) means the number average value of the thickness of the inorganic filler (B) in the composition.
Moreover, in this specification, the average length of an inorganic filler (B) means the number average value of the length of the inorganic filler (B) in a composition.

Moreover, in the composition of this embodiment, the average aspect-ratio of an inorganic filler (B) means the value represented by following formula (1).
Average aspect ratio of inorganic filler (B) = average length of inorganic filler (B) in composition / average thickness of inorganic filler (B) in composition Formula (1)

The glass transition point of the thermoplastic resin (A) _{(T g)} is preferably from 50 ° C. to 250 DEG ° C..
When the glass transition point of the thermoplastic resin (A) is 50 ° C. or more, it is more excellent in practicality of the dental member (for example, practicality when the dental member is used in the oral cavity).
When the glass transition point of the thermoplastic resin (A) is 250 ° C. or less, it is more excellent in production suitability when mixed with the inorganic filler (B) to form a composition.

  In addition, the thermoplastic resin (A) has at least one ring selected from the group consisting of an aromatic ring and an aliphatic ring from the viewpoint of further suppressing the decrease in the bending strength and bending elastic modulus of the dental member due to water absorption. It is preferable that the structural unit which has is included.

Moreover, it is preferable that a thermoplastic resin (A) contains polyamide from a viewpoint of the bending strength and bending elastic modulus (especially bending strength) of a dental member.
Furthermore, it is more preferable that the thermoplastic resin (A) includes a polyamide having an amide bond concentration of 17% by mass to 37% by mass.
When the concentration of the amide bond in the polyamide is 17% by mass or more, the bending strength and the bending elastic modulus of the dental member are further improved.
When the concentration of the amide bond in the polyamide is 37% by mass or less, the water absorption of the dental member is further reduced. By reducing the water absorption of the dental member, the bending strength and the bending elastic modulus of the dental member are maintained high over a long period of use.

Here, the concentration of the amide bond in the polyamide refers to the ratio (mass%) of the mass of the amide bond in the structural unit of the polyamide.
For example, in the case of polyamide 66, the structural unit of polyamide 66 is —CO— (CH ₂ ) ₄ —CONH— (CH ₂ ) ₆ —NH—. The molecular weight of this structural unit is 226. The structural unit includes two amide bonds (—CONH—; molecular weight 43). Therefore, the concentration of the amide bond in the polyamide 66 is 38% by mass according to the following formula.
Concentration of amide bond in polyamide 66 (mass%) = ((43 × 2) / 226) × 100 = 38

  It is preferable that a thermoplastic resin (A) contains an amorphous resin from a viewpoint of the aesthetics (namely, transparency) and moldability of a dental member.

Moreover, content of the inorganic filler (B) in the composition of this embodiment is 5 mass%-50 mass% with respect to the total content of a thermoplastic resin (A) and an inorganic filler (B). It is preferable.
When the content of the inorganic filler (B) is 5% by mass or more, the bending strength and the bending elastic modulus of the dental member are further improved.
When the content of the inorganic filler (B) is 50% by mass or less, the toughness of the dental member is further improved. Moreover, the adhesiveness of a dental member and another member (for example, below-mentioned floor member) improves more as content of an inorganic filler (B) is 50 mass% or less.

There is no restriction | limiting in particular in the form of the dental composition of this embodiment.
As a form of the dental composition of this embodiment, solid forms, such as a powder form and a pellet form, are preferable.

<Thermoplastic resin (A)>
The thermoplastic resin (A) is at least one thermoplastic resin selected from the group consisting of polyamide and polyester.
The preferred embodiment of the thermoplastic resin (A) is as described above.

As the polyamide, polyamide 12 (PA12), polyamide 1010 (PA1010), polyamide 610 (PA610), polyamide 66 (PA66), polyamide 6I-MACMI-MACMT, polyamide 6I-6T-MACMI, polyamide MXD10, polyamide MXD6, polyamide 6T -66 (PA6T-66) polyamide 6I-6T (PA6I-6T), polyamide 9T (PA9T), polyamide 10T (PA10T), and the like.
As the polyamide, a polyamide containing a structural unit having at least one ring selected from the group consisting of an aromatic ring and an aliphatic ring, from the viewpoint of further suppressing a decrease in bending strength and bending elastic modulus of the dental member due to water absorption Are preferred, polyamide 6I-MACMI-MACMT, polyamide 6I-6T-MACMI, polyamide MXD10, polyamide MXD6 or PA6I-6T are more preferred, and PA6I-6T is particularly preferred.
The polyamide is preferably an amorphous polyamide from the viewpoint of aesthetics (that is, transparency) and moldability, more preferably polyamide 6I-MACMI-MACMT, polyamide 6I-6T-MACMI, or PA61-6T, PA6I-6T is particularly preferred.

  Polyesters include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polycyclohexylene dimethylene terephthalate (PCT), glycol modified polyethylene terephthalate (PET-G), glycol modified polycyclohexylene dimethylene terephthalate (PCT-G). , Polyarylate (PAR), and the like.

<Inorganic filler (B)>
The inorganic filler (B) is an inorganic filler having an average thickness of 0.1 μm to 160 μm and an average aspect ratio of 2.0 to 65.
The average thickness of the inorganic filler (B) is preferably 1.0 μm to 100 μm, more preferably 2.0 μm to 20 μm, and particularly preferably 2.0 μm to 10 μm.
The average aspect ratio of the inorganic filler (B) is preferably 2.0 to 40, more preferably 2.0 to 20, and particularly preferably 3.0 to 15.

The average length of the inorganic filler (B) is preferably 300 μm or less, more preferably 200 μm or less, and particularly preferably 100 μm or less.
The lower limit of the average length of the inorganic filler (B) is preferably 1.0 μm, more preferably 5.0 μm, and particularly preferably 10 μm.

The shape of the inorganic filler (B) is not particularly limited as long as it is a long shape satisfying an average aspect ratio of 2.0 to 65.
Here, the concept of “long shape” includes a fiber shape.

  The inorganic filler (B) may be a surface-treated inorganic filler.

As the inorganic filler (B), wollastonite, potassium titanate, alumina / mullite fiber, carbon fiber, aluminum borate, silicon carbide, silicon nitride, magnesium borate, zinc oxide, titanium boride (TiB ₂ ), Etc.

In the composition of the present embodiment, the total content of the thermoplastic resin (A) and the inorganic filler (B) is preferably 60% by mass or more, more preferably 70% by mass or more, based on the total amount of the composition. 80 mass% or more is particularly preferable.
There is no restriction | limiting in particular in the upper limit of the total content of a thermoplastic resin (A) and an inorganic filler (B), and 100 mass% may be sufficient with respect to the whole quantity of a composition.

<Other ingredients>
The composition of this embodiment may contain other components other than the thermoplastic resin (A) and the inorganic filler (B).
For example, the composition of this embodiment may contain a color material from the viewpoint of aesthetics.
The color material is not particularly limited.
The color material may be any of a pigment, a dye, and a pigment.
Examples of the coloring material include synthetic tar dyes and aluminum lakes thereof, inorganic pigments, natural dyes, and the like.
Moreover, the composition of this embodiment may contain resin other than a thermoplastic resin (A), fillers other than an inorganic filler (B), etc. in the range which does not impair the effect of this invention.

  The method for producing the composition of the present embodiment is not particularly limited as long as the method can mix the thermoplastic resin (A) and the inorganic filler (B) (and other components as necessary).

[Dental mill blank]
The dental mill blank of this embodiment contains the dental composition of this embodiment described above. For this reason, the dental member excellent in bending strength, a bending elastic modulus, toughness, surface smoothness, etc. can be manufactured by cutting the dental mill blank of this embodiment.

  The dental mill blank of the present embodiment is preferably used for manufacturing a dental member selected from inlays, onlays, crowns, bridges, clasps, and denture frames by cutting.

The thickness of the dental mill blank of this embodiment is preferably 10 mm to 30 mm.
When the thickness is 10 mm or more, dental members of various sizes can be manufactured.
When the thickness is 30 mm or less, it is possible to reduce a waste portion when manufacturing a dental member by cutting.

There is no restriction | limiting in particular in the shape of the dental mill blank of this embodiment.
Examples of the shape of the dental mill blank of the present embodiment include a disk shape, a rectangular parallelepiped shape (including a cubic shape), an elliptic cylinder shape (including a cylindrical shape), and the like.

Moreover, there is no restriction | limiting in particular also in the manufacturing method of the dental mill blank of this embodiment.
As a manufacturing method of the dental mill blank of this embodiment, the method of shape | molding the dental composition of this embodiment in the shape of a dental mill blank by injection molding etc. is mentioned. Moreover, the method of cutting out the dental mill blank of this embodiment from the round bar-shaped molded object which uses the dental composition of this embodiment as a raw material is also mentioned.

[Dental material]
The dental member of this embodiment contains the dental composition of this embodiment.
For this reason, the dental member of this embodiment is excellent in bending strength, a bending elastic modulus, toughness, surface smoothness, aesthetics, etc.
In addition, the dental member of the present embodiment is advantageous in terms of aesthetics, weight, wearing feeling, prevention of metal allergy, and the like as compared with a metal dental member.

  The dental member of this embodiment is preferably a dental member selected from inlays, onlays, crowns, bridges, clasps, and denture frames.

[Method of manufacturing dental member]
There is no restriction | limiting in particular in the method of manufacturing the dental member of this embodiment.
Examples of the method for producing the dental member of the present embodiment include a method of producing the dental composition of the present embodiment in the form of powder or pellets by a molding method such as injection molding.

Moreover, as a method of manufacturing the dental member of the present embodiment, a method including a cutting process of obtaining the dental member by cutting the dental mill blank of the present embodiment described above can also be mentioned.
The cutting step is preferably a step in which the dental mill blank of the present embodiment described above is cut by a CAD (Computer Aided Design) / CAM (Computer Aided Manufacturing) system to obtain a dental member.
Cutting by the CAD / CAM system can be performed using a CNC (Computer Numerical Control) cutting machine in accordance with a cutting program created by CAD / CAM software, for example.
The cutting program is created based on, for example, information on a three-dimensional shape of a dental member model that is prepared in advance. Information on the three-dimensional shape of the dental member model is obtained, for example, by scanning the dental member model with a 3D scanner.

The manufacturing method of the said dental member may have other processes other than a cutting process as needed.
Examples of other processes include a finishing process by polishing and the like, a coloring process for coloring dental members, and the like.
The dental member formed by the above method for producing a dental member has excellent surface smoothness even after polishing.

[Denture base]
The denture base of the present embodiment includes the dental member of the present embodiment and a denture base member fixed to the dental member.
The denture base of this embodiment is suitable as a denture base for local dentures (so-called partial dentures).
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.

Here, the denture base member is a member of the denture base, and refers to a member simulating a gum.
The denture base member preferably contains an acrylic resin and a coloring material.
Here, the acrylic resin is at least one selected from the group consisting of a structural unit derived from acrylic acid, a structural unit derived from methacrylic acid, a structural unit derived from acrylate, and a structural unit derived from methacrylate. Refers to resin containing.

  Moreover, it is preferable that the dental member of this embodiment fixed to the denture base member is a clasp or a denture frame.

[Method of manufacturing denture base]
As an example of the method for producing the denture base of the present embodiment, the above-described cutting step of cutting the dental mill blank of the present embodiment to obtain a dental member, and building up a resin material on the dental member, And a build-up step of forming a denture base member fixed to the dental member.
The cutting process in the above example is the same as the cutting process in the dental member manufacturing method described above.

  Moreover, as a resin material in the said build-up process, the composition of acrylic resin or an acrylic resin and a coloring material, etc. are mentioned.

The manufacturing method of the denture base in the above example may have other processes other than the cutting process and the build-up process as necessary.
Examples of the other steps include a step of coloring at least one of a dental member and a denture base member after the build-up step.

[Bed denture]
The denture of the present embodiment includes the denture base of the present embodiment and an artificial tooth fixed to the denture base.
The plate denture of this embodiment is suitable as a local denture.
The plate 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.
Further, the artificial tooth may contain an inorganic filler or the like in addition to the acrylic resin.

[Method of manufacturing denture]
As an example of the method of manufacturing the denture of the present embodiment, by cutting the dental mill blank of the present embodiment described above to obtain a dental member, and by building a resin material on the dental member, A build-up process for forming a denture base member fixed to the dental member, and an artificial tooth fixing process for fixing an artificial tooth to the denture base member.
The manufacturing method of the plate denture in the above example may have other processes other than the cutting process, the build-up process, and the artificial tooth fixing process as necessary.

The artificial tooth can be fixed by an ordinary 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 plate denture in the above example may have other processes other than the cutting process, the build-up process, and the artificial tooth fixing process as necessary.
Examples of the other steps include a step of coloring at least one of a dental member and a denture base member after the build-up step.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these examples.

<Raw material>
The raw materials used in this example are as follows.

-Thermoplastic resin-
Polyamide a:
“GRIVORY G21” manufactured by EMS (brand) (amorphous polyamide having an aromatic ring structure (specifically PA6I-6T), glass transition point (Tg) 125 ° C., amide bond concentration 35% by mass)
Polyester a:
"SKYGREEN KN100" (brand) (manufactured by SK Chemicals) (amorphous polyester having an aromatic ring structure (specifically, glycol-modified polyethylene terephthalate (PETG)), glass transition point (Tg) 80 ° C)

-Inorganic filler-
-Filler a:
“NYGLOS 4W-10222” (brand) manufactured by Nyco (wollastonite, average thickness 4.5 μm, average length 50 μm (average length 30 μm after mixing described later), long shape)
-Filler b:
“PC-3” (brand) made by Ishihara Sangyo Co., Ltd. (titanium oxide, average particle size 0.2 μm, shape is spherical)
-Filler c:
“ECS03T T790DE” (brand) manufactured by Nippon Electric Glass Co., Ltd. (glass fiber, average thickness 6 μm, average length 3000 μm (average length 400 μm after mixing described later), the shape is long)
-Filler d:
“M60H” (brand) made by Repco (mica, average particle size 160 μm, shape is a scale shape)

[Example 1]
<Preparation of dental composition and dental mill blank>
Mixing the polyamide a as a thermoplastic resin and the filler a as an inorganic filler in a ratio that the content of the inorganic filler is 15% by mass with respect to the total amount of the thermoplastic resin and the inorganic filler. A pellet made of the composition was obtained. The mixing was performed using an extruder “ZSK26” (model number) manufactured by Coperion under the condition of a maximum cylinder temperature of 260 ° C.

<Preparation of dental mill blank>
A disk-shaped molded article having a diameter of 100 mm and a thickness of 10 mm was obtained by injection molding using pellets made of the dental composition. Injection molding was performed using an injection molding machine “SE100EV” (model number) manufactured by Sumitomo Heavy Industries, Ltd. under conditions of a cylinder temperature of 275 ° C. and a mold temperature of 40 ° C.

<Evaluation>
The following evaluation was performed using the dental composition pellet and the dental mill blank. The evaluation results are shown in Table 1 below.

(Measurement of average aspect ratio after mixing)
First, the average thickness and average length of the inorganic filler after the above mixing were determined as follows.
The resin component in the pellet made of the dental composition was completely dissolved with hexafluoroisopropanol, and the inorganic filler in the pellet was recovered. The recovered inorganic filler was observed with a scanning electron microscope (SEM; Hitachi S-4700 SEM). Based on the obtained SEM image, the thickness and length of the inorganic filler were measured using image analysis software (QWin V3 manufactured by Leica). This measurement was performed on 200 inorganic fillers.
Based on the above results, the number average value of the thicknesses of the 200 inorganic fillers was calculated and set as “average thickness”. Furthermore, the number average value of the lengths of 200 inorganic fillers was calculated and used as “average length”.
Next, the average aspect ratio of the inorganic filler after mixing was determined by dividing the average length by the average thickness (ie, according to the above-described formula (1)).

(Measurement of flexural strength and flexural modulus)
A test piece having a length of 64 mm, a width of 10 mm, and a thickness of 3.3 mm was cut out from the dental mill blank, and the cut test piece was measured for bending strength and bending elastic modulus in accordance with JIS T6501 (2012). . The measurement was performed using a tensile / compression universal testing machine 210X manufactured by Intesco.

(Measurement of surface roughness Ra)
One side of the test piece used for the measurement of the bending strength and the flexural modulus was polished for 10 minutes using a lathe and three types of polishing paper. Next, the surface polished using a lathe and three types of polishing papers was further polished for 10 minutes using a laser and an abrasive. Next, the surface roughness Ra of the surface polished with the laser and the abrasive was measured using a surface roughness measuring machine (Surfcom 130A manufactured by Tokyo Seimitsu Co., Ltd.) according to JIS B 0601 (1994).
In addition, as the lathe, the abrasive paper, the laze, and the abrasive, the following were used.
·lathe:
ECOMET4 (model number) manufactured by BUEHLER
・ Abrasive paper:
Silicon Carbide Grinding Paper Grit 120 / P120 (model number), Grit400 / P800 (model number), and CarbiMet Grit 600 / P1200 (model number) (above, manufactured by BUEHLER) ・ Raise:
Speedraise α (model number) manufactured by Yoshida Seisakusho
·Abrasive:
All Shine (model number) manufactured by Akiyama Sangyo Co., Ltd.

(Measurement of Izod impact strength)
A test piece having a length of 64 mm, a width of 12.7 mm, and a thickness of 3.2 mm was cut out from the dental mill blank, and the cut out test piece was notched using a notching tool A-4 manufactured by Toyo Seiki Seisakusho. Went. Using the obtained notched specimen, Izod impact strength was measured according to ASTM D256.

[Examples 2 to 5]
The same operation as in Example 1 was performed except that the combination of the type of thermoplastic resin, the type of inorganic filler, and the content of the inorganic filler was changed as shown in Table 1.
The results are shown in Table 1.

[Comparative Examples 1-9]
The combination of the type of thermoplastic resin, the type and presence of inorganic filler, and the content of inorganic filler was changed as shown in Table 1, and in Comparative Examples 8 and 9, the maximum cylinder temperature during mixing was 270 ° C. In Comparative Examples 1, 3, and 5-7, the cylinder temperature at the time of injection molding was changed to 260 ° C., and in Comparative Examples 8 and 9, the cylinder temperature at the time of injection molding was changed to 270 ° C. The same operation as 1 was performed. However, the average aspect ratio of the filler c was measured using an optical microscope (DM3000 manufactured by Leica) instead of SEM.
The results are shown in Table 1.

-Description of Table 1-
-Content (mass%) of an inorganic filler shows content (mass%) of an inorganic filler with respect to the total content of a thermoplastic resin and an inorganic filler.
“ND” means no measurement result (No Data).
-Since the filler D (mica) is a scale-shaped filler, the average aspect-ratio in this specification cannot be defined.

As shown in Table 1, the dental composition has at least one thermoplastic resin selected from the group consisting of polyamide and polyester, an average thickness of 0.1 to 160 μm, and an average aspect ratio of 2.0 to In Examples 1 to 5 containing an inorganic filler of 65, the dental mill blank is excellent in bending strength, bending elastic modulus, and toughness (Izod impact strength), and further has a surface roughness Ra. It was kept small. Thus, by cutting out from the dental mill blanks of Examples 1 to 5, a dental member having excellent bending strength, bending elastic modulus, and toughness (Izod impact strength) and a small surface roughness Ra can be produced. It was suggested.
On the other hand, in Comparative Examples 1 and 3 in which the dental composition does not contain an inorganic filler, and in Comparative Examples 2 and 4 in which the inorganic filler contained in the dental composition is only a spherical inorganic filler, both , Bending strength and flexural modulus decreased.
Further, the inorganic filler contained in the dental composition is only an inorganic filler having an average aspect ratio exceeding 65, and Comparative Examples 5 to 7, and the inorganic filler contained in the dental composition has an average aspect ratio. In Comparative Examples 8 and 9, which are only scaly inorganic fillers for which the ratio cannot be defined, the surface roughness Ra increased.

[Reference Example 1]
<Relationship between amide bond concentration and water absorption>
PA6I-6T (amide bond concentration: 35% by mass), PA12 (amide bond concentration: 22% by mass), PA1010 (amide bond concentration: 25% by mass), PA610 (amide bond concentration: 30% by mass), PA66 (amide bond) Concentration: 38% by mass), MXD10 (amide bond concentration: 28% by mass), and MXD6 (amide bond concentration: 35% by mass) of 7 types of polyamides were measured for water absorption. The water absorption rate of the polyamide was measured as follows.
Prepare a test piece for Izod impact test (length 64mm, width 12.7mm, thickness 3.2mm, no notch) based on ASTM D256 made of polyamide, and its mass (hereinafter referred to as "mass before immersion") Was measured with an electronic balance.
The test piece after mass measurement was immersed in a water tank kept at 37 ± 1 ° C., and taken out from the water tank after a certain period of time. Next, the water adhering to the test piece is sufficiently wiped off with Kimwipe within 30 seconds after being taken out of the water tank, and 30 seconds after being taken out of the water tank, the mass of the test piece (hereinafter referred to as “mass after immersion”). ) Was measured with an electronic balance.
Based on the mass before the immersion and the mass after the immersion, the water absorption rate of the polyamide was calculated.

FIG. 1 is a graph showing the relationship between the immersion time in which the polyamide is immersed in water and the water absorption rate of the polyamide (Water Sorption).
FIG. 2 is a graph showing the relationship between the polyamide amide bond concentration (Concentration of Amide-bonds) and the polyamide water absorption rate, based on the graph shown in FIG.
As shown in FIG. 2, it was confirmed that the water absorption can be reduced when the concentration of the amide bond is 17% by mass to 37% by mass.
The higher the water absorption rate of the polyamide, the lower the bending strength and the bending elastic modulus of the dental mill blank containing the polyamide.
Therefore, by using a dental composition containing a polyamide having an amide bond concentration of 17% by mass to 37% by mass, a dental member capable of maintaining high bending strength and flexural modulus over a long period of use is manufactured. can do.

Claims (15)

At least one thermoplastic resin (A) selected from the group consisting of polyamide and polyester;
An inorganic filler (B) having an average thickness of 0.1 to 160 μm and an average aspect ratio of 2.0 to 65;
A dental composition containing   The dental composition according to claim 1, wherein the thermoplastic resin (A) has a glass transition point of 50C to 250C.   The dental composition according to claim 1 or 2, wherein the thermoplastic resin (A) includes a structural unit having at least one ring selected from the group consisting of an aromatic ring and an aliphatic ring.   The dental composition according to any one of claims 1 to 3, wherein the thermoplastic resin (A) includes a polyamide having an amide bond concentration of 17% by mass to 37% by mass.   The dental composition according to any one of claims 1 to 4, wherein the thermoplastic resin (A) contains an amorphous resin.   The content of the inorganic filler (B) is 5% by mass to 50% by mass with respect to the total content of the thermoplastic resin (A) and the inorganic filler (B). The dental composition according to any one of the above.   The dental mill blank containing the dental composition of any one of Claims 1-6.   The dental mill blank according to claim 7, which is used for manufacturing a dental member selected from an inlay, an onlay, a crown, a bridge, a clasp, and a denture frame by cutting.   The dental mill blank according to claim 7 or 8, wherein the thickness is 10 mm to 30 mm.   The dental member containing the dental composition of any one of Claims 1-6.   A denture base comprising the dental member according to claim 10 and a denture base member fixed to the dental member.   A denture having the denture base according to claim 11 and an artificial tooth fixed to the denture base member of the denture base.   The manufacturing method of the dental member which has the cutting process which cuts the dental mill blank of any one of Claims 7-9, and obtains a dental member. A cutting step of cutting the dental mill blank according to any one of claims 7 to 9 to obtain a dental member;
A build-up step of forming a denture base member fixed to the dental member by building a resin material on the dental member;
The manufacturing method of the denture base which has this. A cutting step of cutting the dental mill blank according to any one of claims 7 to 9 to obtain a dental member;
A build-up step of forming a denture base member fixed to the dental member by building a resin material on the dental member;
An artificial tooth fixing step of fixing artificial teeth to the denture base member;
The manufacturing method of the denture which has this.