JP2021126854A - Dental light-curing composition - Google Patents

Abstract

To provide a dental light-curing composition with good molding accuracy and reduced coloring of the cured material.SOLUTION: A dental light-curing composition for use in photofabrication contains (A) 50-72% by weight of ethoxylated bisphenol A dimethacrylate, (B) 20-32% by weight of aliphatic urethane (meth)acrylate, (C) 1-3% by weight of a photoinitiator, and (D) 0.05-4% by weight of hydroquinone monoalkyl ether.SELECTED DRAWING: None

Description

The present invention relates to dental photocurable compositions used as materials for, for example, crowns, artificial teeth and the like.

In recent years, three-dimensional modeling technology has been used to efficiently manufacture a three-dimensional shape of an article. For example, Patent Document 1 describes a composition having a viscosity and a curing rate suitable for three-dimensional modeling for the purpose of realizing the mechanical properties required for artificial teeth and denture bases. The compositions described in the same document are solutions in which polymethylmethacrylate is dissolved in a methylmethacrylate monomer solvent, polyfunctional aliphatic (meth) acrylate, and aliphatic urethane (meth) acrylate, based on the total weight of the composition. Each predetermined amount contains an oligomer, a bifunctional bisphenol-A dimethacrylate, a photoinitiator, a light stabilizer, and a coloring pigment.

Special Table 2016-525150

When three-dimensionally modeling a crown or artificial tooth, the cured product must have predetermined physical characteristics (bending characteristics, hardness, water absorption, etc.) and an appearance suitable for dentistry, and it is precisely modeled by three-dimensional modeling. It is necessary that the molding accuracy is good.
In recent years, a UV-LED light source that generates less heat is often used as a modeling light source, and it is necessary to select a photopolymerization initiator suitable for an emission wavelength of 365 to 405 nm. On the other hand, when an starting material effective for a wavelength of 350 nm or more is used, discoloration due to the starting material remaining in the material or the reaction product often becomes a problem. In the case of crowns and artificial teeth, a transparent and delicate tooth color is required, so the cured product has predetermined physical characteristics (bending characteristics, hardness, water absorption, etc.) and a photocurable appearance suitable for dentistry. It was difficult to realize the composition.
Therefore, an object of the present invention is to provide a dental photocurable composition capable of accurately forming a cured product having the physical characteristics and appearance required for dentistry.

The present invention is based on the finding that a dental photocurable composition capable of accurately forming a cured product having necessary physical properties and appearance can be obtained by blending a predetermined amount of a specific component. It has the configuration of.

[1] A photocurable composition used for stereolithography, which comprises (A) 50 to 72% by weight of ethoxylated bisphenol A dimethacrylate and (B) 20 to 32% by weight of aliphatic urethane (meth) acrylate. A dental photocurable composition containing (C) 1 to 3% by weight of a photopolymerization initiator and (D) 0.05 to 3% by weight of a hydroquinone monoalkyl ether.

[2] The (A) ethoxylated bisphenol A dimethacrylate is a bifunctional bisphenol A dimethacrylate, the (B) aliphatic urethane (meth) acrylate is a urethane dimethacrylate, and the (C) photopolymerization initiation. The dental photocurable composition according to [1], wherein the agent is phenylbis (2,4,6-trimethylbenzoyl) phosphine oxide, and the (D) hydroquinone monoalkyl ether is a hydroquinone monomethyl ether.
[3] The dental photocurable composition according to [2], which does not contain (meth) acrylate other than the (A) ethoxylated bisphenol A dimethacrylate and the (B) aliphatic urethane (meth) acrylate.

（式（１）中、Ｒ¹、Ｒ²、Ｒ¹¹、およびＲ¹²は、それぞれ独立に、水素原子またはメチル基を表す。Ｒ³およびＲ⁴は、それぞれ独立に、直鎖または分岐鎖の炭素原子数２〜４のアルキレン基を表す。ｍおよびｎは独立に繰り返し数の平均値を示しており、１≦（ｍ＋ｎ）≦４である。） [4] The dental photocurable composition according to [2], wherein the (A) ethoxylated bisphenol A dimethacrylate is represented by the following formula (1).

(In formula (1), R ¹ , R ² , R ¹¹ and R ¹² each independently represent a hydrogen atom or a methyl group; R ³ and R ⁴ each independently represent a linear or branched chain. It represents an alkylene group having 2 to 4 carbon atoms. M and n independently indicate the average value of the number of repetitions, and 1 ≦ (m + n) ≦ 4.

（ｍおよびｎは、繰り返し数の平均値を示しており、２≦（ｍ＋ｎ）≦３である。） [5] The dental photocurable composition according to [2], wherein the (A) ethoxylated bisphenol A dimethacrylate is represented by the following formula (2).

(M and n indicate the average value of the number of repetitions, and 2 ≦ (m + n) ≦ 3.)

[6] The dental photocurable composition according to any one of [1] to [5], which is used for producing a crown or an artificial tooth.

Since the dental photocurable composition of the present invention contains each component (A) to (C) in a predetermined amount, it becomes a liquid having a viscosity suitable for stereolithography, and is used as a dental crown or artificial. It is possible to accurately model a cured product having physical properties suitable for teeth. Further, since the coloration of the cured product is suppressed by the (D) hydroquinone monoalkyl ether, it is possible to obtain a cured product with high aesthetics suitable for a crown or an artificial tooth, in which the color of the cured product can be easily adjusted.

Drawing-substituting photographs showing the color tones of the samples of Comparative Example 1 and Examples 5 to 7.

The dental photocurable composition of the present invention (hereinafter, appropriately referred to as “composition”) is (A) ethoxylated bisphenol A dimethacrylate, (B) aliphatic urethane (meth) acrylate, and (C) photopolymerization initiator. , And (D) hydroquinone monoalkyl ether. Hereinafter, each component will be described. Each component (A) to (D) may be composed of one kind or two or more kinds.

(A) Ethylated Bisphenol A Dimethacrylate The composition of the present invention contains ethoxylated bisphenol A dimethacrylate having a bisphenol skeleton (benzene skeleton) to have a viscosity suitable for stereolithography using a 3D printer. At the same time, the crosslink density during curing is increased. As a result, it is possible to produce a cured product having high hardness and a small amount of water absorption.

The content of ethoxylated bisphenol A dimethacrylate in 100% by weight of the composition from the viewpoint of forming a cured product having physical characteristics (bending strength, hardness, water absorption) suitable for dental crowns and artificial teeth with high modeling accuracy. Is preferably 50 to 72% by weight, more preferably 61 to 70% by weight, and even more preferably 66 to 70% by weight. In addition, in this specification, "A to B weight%" means "A weight% or more and B weight% or less".

From the viewpoint of obtaining a cured product having high hardness, the bifunctional bisphenol A dimethacrylate represented by the above formula (1) is preferable as the (A) ethoxylated bisphenol A dimethacrylate, and the bifunctional bisphenol A dimethacrylate represented by the formula (2) is preferable. Functional bisphenol A dimethacrylate is more preferred. Among those represented by the formula (2), those in which (m + n) is 2.2 or more and 2.8 or less [2.2 ≦ (m + n) ≦ 2.8] are more preferable, and (m + n) is 2.3 or more and 2 It is particularly preferable that it is 1.6 or less [2.3 ≦ (m + n) ≦ 2.6].

(B) Aliphatic Urethane (Meta) Acrylate The composition of the present invention contains an aliphatic urethane (meth) acrylate to improve the surface curability. By using ethoxylated bisphenol A dimethacrylate and aliphatic urethane (meth) acrylate in combination, the composition can be made into a liquid having a viscosity suitable for stereolithography by a 3D printer (three-dimensional printer). In addition, by stereolithography, it is possible to produce a cured product having physical properties (bending, hardness, water absorption) suitable for crowns and artificial teeth.

From the viewpoint of obtaining a cured product suitable for dentistry, the content of the aliphatic urethane (meth) acrylate in 100% by weight of the composition is preferably 20 to 32% by weight, more preferably 25 to 31% by weight.

From the viewpoint of increasing the hardness and producing a cured product having a small water absorption, the content of the aliphatic urethane (meth) acrylate is 20 to 250 parts by weight with respect to 100 parts by weight of (A) ethoxylated bisphenol A dimethacrylate. Preferably, 25 to 100 parts by weight is more preferable, and 30 to 50 parts by weight is further preferable.

Examples of the aliphatic urethane (meth) acrylate include urethane dimethacrylate and urethane methacrylate, and urethane dimethacrylate is preferable. In the present invention, the (meth) acrylate includes acrylate and methacrylate.

The composition of the present invention can be carried out assuming that it does not contain (meth) acrylate other than (A) ethoxylated bisphenol A dimethacrylate and (B) aliphatic urethane (meth) acrylate. Further, as another monomer, (meth) acrylate other than the components (A) and (B) may be contained. Examples of other monomers include dimethacrylate, and the addition of dimethacrylate may facilitate the adjustment of the viscosity of the composition.

(C) Photopolymerization Initiator The photopolymerization initiator is not particularly limited as long as it generates radicals by irradiating with light, but those that generate radicals at the wavelength of light used for photoforming are preferable. The wavelength of light used in stereolithography is generally 365 nm to 500 nm, but practically it is preferably 365 nm to 430 nm, and more preferably 365 nm to 420 nm.

Examples of the photopolymerization initiator include alkylphenone compounds, acylphosphine oxide compounds, titanosen compounds, oxime ester compounds, benzoin compounds, acetophenone compounds, benzophenone compounds, thioxanthone compounds, and α-acyloxime. Examples thereof include ester compounds, phenylglioxylate compounds, benzyl compounds, azo compounds, diphenyl sulfide compounds, organic dye compounds, iron-phthalocyanine compounds, benzoin ether compounds, and anthraquinone compounds.

Of these, acylphosphine oxide compounds such as phenylbis (2,4,6-trimethylbenzoyl) -phosphine oxide and diphenyl (2,4,6-trimethylbenzoyl) -phosphine oxide are available from the viewpoint of reactivity and the like. preferable. Phenylbis (2,4,6-trimethylbenzoyl) -phosphine oxide is particularly preferable because it improves the molding accuracy of the composition.

From the viewpoint of obtaining a composition with good molding accuracy, the blending amount of the photopolymerization disclosure agent such as phenylbis (2,4,6-trimethylbenzoyl) -phosphine oxide is preferably 1 to 3% by weight, and 1.2 to 2% by weight. 8.8% by weight is more preferable, and 1.5 to 2.5% by weight is further preferable.

(D) Hydroquinone Monoalkyl Ether When the composition contains hydroquinone monoalkyl ether, it is possible to prevent the cured product obtained by stereolithography of the composition from being colored reddish brown or the like. Examples of the hydroquinone monoalkyl ether include hydroquinone monomethyl ether.

The content of hydroquinone monoalkyl ether in 100% by weight of the composition is preferably 0.05 to 3% by weight, preferably 0.1, from the viewpoint of obtaining a composition with good molding accuracy while suppressing discoloration of the cured product. ~ 2% by weight is more preferable. Further, from the viewpoint of obtaining a necessary and sufficient blending amount for suppressing reddish brown coloring, 1% by weight or less is preferable, and 0.5% by weight or less is more preferable.

In order to adjust the color of the cured product to a color suitable for dental crowns and dentures, for example, about 0.1 to 3% by weight of a coloring pigment is used in 100% by weight of the composition. Regardless of the color of the composition on which the cured product is based, it is possible to adjust the color of the cured product using a coloring pigment. However, when the amount of the coloring pigment such as titanium oxide is large, it becomes difficult to obtain a cured product having an appropriate transparency that is preferable for dentistry. Therefore, the composition of the present invention contains hydroquinone monoalkyl ether in order to suppress the coloring of the cured product containing no coloring pigment. As a result, the amount of the coloring pigment required to adjust the color of the cured product can be reduced. For example, the blending amount of the coloring pigment in 100% by weight of the composition can be less than 1.0% by weight, less than 0.3% by weight, and further less than 0.1% by weight. Therefore, it is possible to prevent an opaque and unnatural color due to the inclusion of a large amount of coloring pigment, and to obtain a cured product having excellent aesthetics and high transparency and suitable for dentistry.

The cured product obtained by stereolithography of the composition of the present invention has little coloring and is excellent in aesthetics. Therefore, it is suitable as a filling material used in the oral cavity for dentistry. Dental fillings include crowns, dentures (dentures), inlays, denture beds, bridges and the like, and are particularly useful as compositions used in the production of crowns or dentures. ..

The composition of the present invention may contain other components of the components (A) to (D). Other components include, for example, other monomers such as dimethacrylate, inorganic fillers, color pigments and the like.

Examples of the stereolithography method using a 3D printer include an SLA (Service Level Agreement) method, a DLP (Digital Light Processing) method, and an inkjet method.

The present invention will be described in more detail by way of examples, but the technical scope of the present invention is not limited to the examples. In the following description, "parts" indicates "parts by weight", "%" indicates "% by weight", and the temperature of the liquid in each step indicates room temperature (about 23 ° C.).

The abbreviations of the raw materials used in Examples, Comparative Examples, and Reference Examples are shown below.
(A) Ethoxylated Bisphenol A Dimethacrylate EBDM-2.6: Ethoxylated Bisphenol A Dimethacrylate (m + n = 2.6)
EBDM-4: Ethoxylated bisphenol A dimethacrylate (m + n = 4)
(B) aliphatic urethane (meth) acrylate UDMA: Urethane dimethacrylate (C) Photopolymerization initiator PB: Phenylbis (2,4,6-trimethylbenzoyl) Phenyloxide DP: Diphenyl (2,4,6-trimethylbenzoyl) ) Phenyloxide (D) Hydroquinone Monoalkyl Ether MEHQ: (Meta) Crylate Other than Hydroquinone Monomethyl Ether (A) (B) HEMA: 2-Hydroxyethyl methacrylate

(Molding equipment)
Using the composition containing each component shown in Tables 1 to 5 in each compounding amount, after modeling with "D30" manufactured by Rapidhape as a 3D printer, the sample is used as a post-cure device by NextDent "LC-3D print box". ] Was used to perform final curing to prepare a sample for measurement.
Each sample used for measuring bending strength, hardness, water absorption, and color tone was prepared to a size according to JIS T 6517: 2011 (sample for bending strength: 2 mm × 2 mm × 25 mm rod-shaped body, hardness / water absorption). -Sample for color adjustment: φ15 mm x 1 mm disk shape). The color tone was also confirmed with a plate-shaped sample having a size of 20 mm × 20 mm × 2 mm, and the molding accuracy was confirmed by manufacturing (modeling) a sample having a crown shape with a ridge.
The results of evaluation using the following evaluation methods are shown in Tables 1 to 5.

(Evaluation method)
The test methods used in the performance evaluation of Examples and Comparative Examples are as follows.
(1) Bending strength and hardness Each test was carried out according to JIS T 6517: 2011.
Evaluation was made according to the following criteria using a bending strength of 80 MPa or more and a Vickers hardness of 18 or more (Hv0.2), which are the standards for a hard resin for crowns.
〇: 10% or more above the standard value (110% or more of the standard value)
Δ: Standard value or more (100% or more and less than 110% of standard value)
X: Less than the standard value (less than 100% of the standard value)

(2) Water absorption A water absorption of 40 μg / mm ³ or less, which is a standard for hard resins for crowns, was used and evaluated according to the following criteria.
〇: 10% or more above the standard value (90% or less of the standard value)
Δ: Above the standard value (more than 90% and less than 100% of the standard value)
×: Less than the standard value (more than 100% of the standard value)

(2) Color tone The color of the molded sample was visually confirmed and evaluated using the following criteria.
〇: Transparent, white, pale yellow △: pale orange ×: orange, reddish brown

(3) Modeling accuracy The shape of the shaped crown was visually confirmed and evaluated using the following criteria.
〇: Can be modeled according to the modeling data △: Cannot be modeled slightly sharper than the modeling data, but there is no modeling defect ×: Modeling cannot be performed according to the modeling data, and there is a modeling defect

（Ｃ）光重合開始剤として、ＰＢ：フェニルビス（２，４，６−トリメチルベンゾイル）ホスフィンオキサイドを用いることにより、３Ｄプリンタを用いた場合に鋭角が形成できる造形精度の良好な組成物となった。

(C) By using PB: phenylbis (2,4,6-trimethylbenzoyl) phosphine oxide as the photopolymerization initiator, a composition having good molding accuracy capable of forming an acute angle when using a 3D printer is obtained. rice field.

（Ａ）エトキシ化ビスフェノールＡジメタクリレートとして、式（２）で示されるＥＢＤＭ−２．６を用いることにより、ビッカース硬度１８以上の硬化物が得られた。この結果から、式（１）における（ｍ＋ｎ）の数値が光造形により得られる硬化物の高度に影響することが分かった。ビッカース硬度１８は、歯冠として要求される硬度であることから、特に、２≦（ｍ＋ｎ）≦３である式（２）で示されるエトキシ化ビスフェノールＡジメタクリレートが、歯冠として用いる硬化物とするために好ましいといえる。

By using EBDM-2.6 represented by the formula (2) as the ethoxylated bisphenol A dimethacrylate, a cured product having a Vickers hardness of 18 or more was obtained. From this result, it was found that the numerical value of (m + n) in the formula (1) affects the altitude of the cured product obtained by stereolithography. Since the Vickers hardness 18 is the hardness required for the crown, in particular, the ethoxylated bisphenol A dimethacrylate represented by the formula (2) in which 2 ≦ (m + n) ≦ 3 is used as the hardened product as the crown. It can be said that it is preferable to do so.

（Ｃ）光造形剤としてＰＢを用いる場合、その配合量が造形精度に影響することが分かった。造形精度の良い組成物とする観点から、組成物１００重量％中におけるＰＢの含有量は、１．２重量％以上が好ましく、１．５重量％以上がより好ましい。

(C) When PB is used as a stereolithography agent, it has been found that the blending amount affects the modeling accuracy. From the viewpoint of producing a composition with good molding accuracy, the content of PB in 100% by weight of the composition is preferably 1.2% by weight or more, more preferably 1.5% by weight or more.

FIG. 1 is a drawing-substituting photograph showing the color tones of the samples of Comparative Example 1 and Examples 5 to 7. As shown in FIGS. 1, 4 and 5, the discoloration of the cured product could be suppressed by the (D) hydroquinone monoalkyl ether. The amount of the hydroquinone monoalkyl ether (D) is preferably 0.1% by weight or more, more preferably 0.2% by weight or more, from the viewpoint of suppressing discoloration. Further, from the viewpoint of molding accuracy, 3% by weight or less is preferable, and 2% by weight or less is more preferable.

The dental photocurable composition of the present invention is suitable as a material for producing a crown or an artificial tooth by stereolithography.

Claims (6)

A photocurable composition used for stereolithography.
(A) Ethoxylated bisphenol A dimethacrylate 50-72% by weight,
(B) Aliphatic urethane (meth) acrylate 20 to 32% by weight,
(C) Photopolymerization initiator 1-3% by weight,
(D) Hydroquinone monoalkyl ether 0.05 to 3% by weight
And, a dental photocurable composition containing. The (A) ethoxylated bisphenol A dimethacrylate is a bifunctional bisphenol A dimethacrylate.
The (B) aliphatic urethane (meth) acrylate is urethane dimethacrylate, and is
The (C) photopolymerization initiator is phenylbis (2,4,6-trimethylbenzoyl) phosphine oxide.
The dental photocurable composition according to claim 1, wherein the (D) hydroquinone monoalkyl ether is a hydroquinone monomethyl ether. The dental photocurable composition according to claim 2, which does not contain (meth) acrylate other than the (A) ethoxylated bisphenol A dimethacrylate and the (B) aliphatic urethane (meth) acrylate. The dental photocurable composition according to claim 2, wherein the (A) ethoxylated bisphenol A dimethacrylate is represented by the following formula (1).

(In formula (1), R ¹ , R ² , R ¹¹ and R ¹² each independently represent a hydrogen atom or a methyl group; R ³ and R ⁴ each independently represent a linear or branched chain. It represents an alkylene group having 2 to 4 carbon atoms. M and n independently indicate the average value of the number of repetitions, and 1 ≦ (m + n) ≦ 4. The dental photocurable composition according to claim 2, wherein the (A) ethoxylated bisphenol A dimethacrylate is represented by the following formula (2).

(M and n indicate the average value of the number of repetitions, and 2 ≦ (m + n) ≦ 3.) The dental photocurable composition according to any one of claims 1 to 5, which is used for producing a crown or an artificial tooth.

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