Dental composition, resin material for dental cutting, and method for producing resin material for dental cutting

Abstract

A dental composition containing: a polymerizable monomer having only one group selected from the group consisting of a urethane group, a urea group, and a carbonate group; and an inorganic filler.

Description

Technical Field

[0001] This invention relates to dental compositions, resin materials for dental cutting, and methods for manufacturing resin materials for dental cutting. Background Technology

[0002] In recent years, in the manufacture of dental restorations, computer-aided design of restorations such as crowns or bridges has been used on a visual basis. By using CAD / CAM devices to manufacture restorations through machining, a certain quality of dental restorations can be stably supplied in a short period of time.

[0003] In the cutting process of CAD / CAM devices, dental cutting resin material (dental resin block, also known as dental blank) is used as the material before the shape is cut (for example, see Patent Document 1).

[0004] [Existing Technical Documents]

[0005] [Patent Documents]

[0006] Patent Document 1: Japanese Patent No. 6739809 Summary of the Invention

[0007] <Problem to be solved by the invention>

[0008] As a resin material for dental cutting, a material with high mechanical strength is desired to ensure stability in the oral cavity.

[0009] The objective of this invention is to provide a dental composition that yields a resin material for dental cutting with high mechanical strength.

[0010] Methods for solving problems

[0011] One embodiment of the present invention is a dental composition comprising a polymeric monomer having only one group selected from the group consisting of urethane, urea, and carbonate groups, and an inorganic filling material.

[0012] <Invention Effects>

[0013] According to one embodiment of the present invention, a dental composition can be provided that yields a dental cutting resin material with high mechanical strength. Detailed Implementation

[0014] Next, specific embodiments of the present invention will be described.

[0015] <Dental Compositions>

[0016] The dental composition of this embodiment contains a polymeric monomer having only one group selected from the group consisting of urethane, urea, and carbonate groups (hereinafter referred to as urethane group, etc.) and an inorganic filling material. In this specification, "dental composition" refers to a composition used in the dental field.

[0017] The urethane group is a bonding group represented by -NHCOO-. The urea group is a bonding group represented by -NHCONH-. The carbonate group is a bonding group represented by -OCOO-.

[0018] Polymerizable monomers that have only one urethane group or the like contain one urethane group or the like, but do not contain two or more urethane groups or the like.

[0019] Polymerizable monomers having only one urethane group are not particularly limited, for example, (meth)acrylates containing only one urethane group. In this specification, (meth)acrylate means a compound having methacryloyloxy and / or acryloyloxy (hereinafter referred to as (meth)acryloyloxy).

[0020] (Meth)acrylates containing only one carbamate group are preferred to be (meth)acrylates having two or more (meth)acryloyloxy groups.

[0021] (Meth)acrylates containing only one carbamate group are represented, for example, by the following formula (1).

[0022] [Chemistry 1]

[0023]

[0024] In formula (1), A1 and A2 are each independently an alkyl group with a side chain having 3 or fewer carbon atoms, which is either (meth)acryloyloxy or (meth)acrylamide. B is a carbamate group. R1 and R2 are each independently an alkyl group with a side chain having 8 or fewer carbon atoms, which is either (meth)acryloyloxy or (meth)acrylamide.

[0025] Here, (meth)acrylamide group refers to methacrylamide group and / or acrylamide group. In addition, acrylamide group represents a substituent represented by -NHCO (CH=CH2).

[0026] Furthermore, A1 and A2 preferably have an alkyl group in the side chain of the (meth)acryloyloxy or (meth)acrylamide group with 2 or fewer carbon atoms, or the side chain of the (meth)acryloyloxy or (meth)acrylamide group does not have an alkyl group. Additionally, R1 and R2 preferably have an alkyl group with 5 or fewer carbon atoms.

[0027] It should be noted that if the number of carbon atoms in the alkyl group is 9 or more, polymeric monomers such as R1 and R2 that have only one urethane group are easily deformed and cannot fully obtain the mechanical strength of the cured product obtained by curing the dental composition containing such polymeric monomers.

[0028] The (meth)acrylate represented by formula (1) above is not particularly limited, for example, it is a (meth)acrylate containing only one urethane group (-NHCOO-) represented by formulas (2) to (6) below.

[0029]

Chemistry 2

[0030]

[0031]

Transformation 3

[0032]

[0033]

Chemistry 4

[0034]

[0035]

Transformation 5

[0036]

[0037]

Transformation 6

[0038]

[0039] The content of polymeric monomers having only one urethane group or the like in the dental composition is not particularly limited, but is preferably 5% by mass or more and 30% by mass or less, more preferably 10% by mass or more and 28% by mass or less, and even more preferably 15% by mass or more and 25% by mass or less. When the content of polymeric monomers having only one urethane group or the like is 5% by mass or more and 30% by mass or less, the cured dental composition can maintain high mechanical strength.

[0040] Furthermore, the content of polymerizable monomers such as those having only one urethane group varies depending on the intended use of the dental composition. When the dental composition is used as a resin material for dental cutting, it is preferably 5% by mass or more and 30% by mass or less, more preferably 10% by mass or more and 25% by mass or less.

[0041] Inorganic fillers are composed of inorganic materials and are contained in the resin composition in particulate form. There are no particular limitations on inorganic fillers; examples include barium glass, strontium glass, and silica powder.

[0042] The inorganic filler material is preferably a hydrophobically treated inorganic filler material. In the hydrophobic treatment of the inorganic filler material, for example, a silane coupling agent can be used. Examples of silane coupling agents include 3-methacryloyloxypropyltrimethoxysilane and 8-methacryloyloxyoctyltrimethoxysilane.

[0043] The amount of silane coupling agent used relative to 100% by mass of the inorganic material constituting the inorganic filler is preferably 0.1% by mass or more and 15% by mass or less, more preferably 0.5% by mass or more and 10% by mass or less, and even more preferably 1% by mass or more and 5% by mass or less.

[0044] The particle size of the main inorganic filler is preferably 0.1 μm to 100 μm, more preferably 0.1 μm to 70 μm, and even more preferably 0.1 μm to 50 μm. Here, particle size refers to the average particle size defined by the median particle size (d50).

[0045] The content of inorganic filling material in the dental composition is not particularly limited, but is preferably 70% to 90% by mass, more preferably 72% to 85% by mass, and even more preferably 75% to 82% by mass. When the content of inorganic filling material is less than 70% by mass, sufficient mechanical strength cannot be obtained. In addition, if it exceeds 90% by mass, the viscosity of the dental composition increases significantly, and therefore, during the curing process, undesirable conditions such as the formation of air bubbles in the cured product may sometimes occur.

[0046] Furthermore, the content of inorganic filling material in the dental composition varies depending on the application of the dental composition. When the dental composition is used as a resin material for dental cutting, it is preferably 70% by mass or more and 90% by mass or less, more preferably 75% by mass or more and 85% by mass or less.

[0047] The dental composition of this embodiment may further contain polymeric monomers other than polymeric monomers containing only one carbamate group (hereinafter referred to as other polymeric monomers).

[0048] As other polymerizable monomers, (meth)acrylates without urethane groups or (meth)acrylates with two or more urethane groups can be used.

[0049] Other polymerizable monomers include, for example, 2,2-bis(4-methacryloyloxypolyethoxyphenyl)propane (Bis-MPEPP), glycerol dimethacrylate (GDMA), neopentyl glycol dimethacrylate (NPGDMA), triethylene glycol dimethacrylate (TEGDMA), bisphenol A glycidyl methacrylate (Bis-GMA), tricyclodecanediethanol dimethacrylate (DCP), trimethylolpropane trimethacrylate (TMPT), and dipentaerythritol hexaacrylate (A-DPH).

[0050] Examples of (meth)acrylates having two or more carbamate groups include di-2-methacryloyloxyethyl-2,2,4-trimethylhexamethylene dicarbamate (UDMA).

[0051] In addition, other polymerizable monomers can be used alone or in combination with two or more.

[0052] The content of other polymeric monomers in the dental composition is not particularly limited, but is preferably 1% to 70% by mass, more preferably 5% to 60% by mass, and even more preferably 10% to 50% by mass. When the content of other polymeric monomers is 1% to 70% by mass, the cured dental composition can maintain high mechanical strength.

[0053] The dental composition of this embodiment may contain other components as long as it does not impair the purpose of the present invention. Other components contained in the dental composition include, for example, polymerization initiators, polymerization accelerators, polymerization inhibitors, chain transfer agents, filling materials (excluding the aforementioned inorganic filling materials), coloring materials, pigments, fluorescent agents, antibacterial agents, etc.

[0054] Examples of polymerization initiators include organic peroxides such as benzoyl peroxide. A single polymerization initiator can be used alone, or two or more can be used in combination.

[0055] The content of the polymerization initiator in the dental composition is not particularly limited, but is, for example, 0.005% to 10% by mass, preferably 0.01% to 5% by mass, and more preferably 0.1% to 3% by mass. If the content of the polymerization initiator in the dental composition is 0.005% to 10% by mass, the polymerization efficiency during curing of the dental composition is improved.

[0056] Examples of filler materials include inorganic fillers other than the aforementioned inorganic fillers, such as zirconium dioxide and alumina dioxide, as well as organic-inorganic composite fillers and clustered fillers. It should be noted that hydrophobicated fillers are preferred. For example, silane coupling agents such as 3-methacryloyloxypropyltrimethoxysilane can be used in the hydrophobication treatment of the filler material.

[0057] Examples of pigments include iron oxide and titanium oxide.

[0058] Examples of fluorescent agents include diethyl-2,5-dihydroxyterephthalate.

[0059] In the dental composition of this embodiment, as described above, it contains a polymeric monomer having only one urethane group, etc. However, the viscosity of a polymeric monomer having only one urethane group tends to be lower than that of a polymeric monomer having two or more urethane groups. Therefore, by containing such a polymeric monomer having only one urethane group, the content of inorganic filling material can be increased compared to the conventional method, and the mechanical strength (e.g., flexural strength) of the polymerized cured dental composition can be improved.

[0060] From the viewpoint of achieving the effect of improving the mechanical strength of the polymerized cured material as described above, the dental composition of this embodiment can be used in various dental materials.

[0061] Examples of dental materials include, for instance, resin materials for dental cutting and machining, composite resins for dental fillings, hard resins for dental use, temporary dental restorative materials, dental filling materials, dental cements, dental bonding materials (including primers for bonding crown restorations), dental primers, tooth surface coating materials, and toothpaste. Among these, the dental composition of this embodiment is suitable for use as a resin material for dental cutting and machining.

[0062] <Resin Materials for Dental Machining>

[0063] The dental cutting resin material of this embodiment can be formed by polymerizing and curing the above-described dental composition. That is, the dental cutting resin material of this embodiment uses the above-described dental composition.

[0064] Furthermore, there are no particular limitations on the method of polymerizing and curing the dental composition; examples include polymerization methods such as heating polymerization, chemical polymerization, and photopolymerization.

[0065] In the dental cutting resin material of this embodiment, since the dental composition of this embodiment is used, the effects of the dental composition can be directly obtained. That is, by polymerizing and curing a dental composition containing a polymeric monomer having only one urethane group and an inorganic filler, the mechanical strength of the dental cutting resin material obtained as the cured product can be improved.

[0066] <Manufacturing Method of Resin Materials for Dental Cutting>

[0067] The method for manufacturing a dental cutting resin material according to this embodiment includes a step of polymerizing and curing the above-described dental composition. That is, the above-described dental composition is used in the method for manufacturing a dental cutting resin material according to this embodiment.

[0068] Furthermore, there are no particular limitations on the method of polymerizing and curing the dental composition. In the above-mentioned dental cutting resin material, the same polymerization method as the polymerization method used to polymerize and cure the dental composition can be used (e.g., thermal polymerization, chemical polymerization, photopolymerization, etc.).

[0069] The polymerization conditions used to polymerize and cure the dental composition are arbitrary. For example, the polymerization temperature is 50°C to 200°C, preferably 80°C to 180°C, and more preferably 110°C to 150°C. In addition, the polymerization time is 20 minutes to 360 minutes, preferably 60 minutes to 240 minutes, and more preferably 100 minutes to 180 minutes.

[0070] Alternatively, the polymerization of the dental composition can also be carried out under pressure. The pressure is 1.0 MPa to 10.0 MPa, preferably 2.0 MPa to 8.0 MPa, and more preferably 3.0 MPa to 5.0 MPa.

[0071] In the method for manufacturing a dental cutting resin material according to this embodiment, since the dental composition of this embodiment is used, the effects of the dental composition can be directly obtained. That is, by polymerizing and curing a dental composition containing a polymeric monomer having only one urethane group and an inorganic filler, the mechanical strength of the dental cutting resin material obtained as the cured product can be improved.

[0072] In the method for manufacturing a dental cutting resin material according to this embodiment, a polymeric monomer having only one urethane group or the like is used as the polymeric monomer contained in the dental composition, and the dental cutting resin material can be manufactured. That is, in the manufacturing method of this embodiment, a dental cutting resin material can be manufactured using only a single monomer.

[0073] Furthermore, when using a mixture of monomers instead of a single monomer, there is a risk of deviations based on the purity of other monomers (the more monomers involved, the greater the risk). Additionally, when using a mixture of monomers instead of a single monomer, the monomers may not mix uniformly (increasing the risk of reduced quality uniformity).

[0074] In contrast, in the method for manufacturing dental cutting resin material according to this embodiment, the dental cutting resin material can be manufactured using only a single monomer, thus reducing the risk of foreign matter contamination due to the reduction of manufacturing steps. Furthermore, by using only a single monomer to manufacture the dental cutting resin material, the manufacturing process can be simplified, thereby reducing manufacturing costs from the perspectives of materials and equipment.

[0075] Example

[0076] The following describes embodiments of the present invention, but the present invention is not limited to these embodiments. Furthermore, unless otherwise specified, numerical values ​​without units are considered mass percentages (mass percentage).

[0077] <Preparation of Resin Materials (Resin Blocks) for Dental Cutting>

[0078] A resin material (resin block) for dental cutting and machining is prepared as a dental composition. First, a monomer solution is prepared by mixing a curable polymerizable monomer and a polymerization initiator (BPO) at the composition ratios shown in Tables 1 and 2.

[0079] In addition, the components represented by symbols or abbreviations in Tables 1 and 2 are as follows.

[0080] ·mUDMA: (meth)acrylate represented by formula (3) above

[0081] ·mUA / MA-1: (meth)acrylate represented by formula (2) above

[0082] ·mUA / MA-2: (meth)acrylate represented by formula (4) above

[0083] ·mUTMA: (meth)acrylate represented by formula (5) above

[0084] ·mUAA / MA: (meth)acrylate represented by formula (6) above

[0085] UDMA: Di-2-methacryloyloxyethyl-2,2,4-trimethylhexamethylene dicarboxylate

[0086] • D-2.6E: 2,2-bis(4-methacryloyloxypolyethoxyphenyl)propane with an average molar number of ethoxy additions of 2.6.

[0087] GDMA: Glyceryl dimethacrylate

[0088] • NPGDMA: Neopentyl glycol dimethacrylate

[0089] ·TEGDMA: Triethylene Dimethacrylate

[0090] •BPO: Benzoyl peroxide (polymerization initiator)

[0091] According to the mixing ratios [mass %) in Tables 3 and 4, the monomer solution and inorganic filler material (silica micro powder + silane-treated glass) were mixed using a rotation-revolution mixer (or a dual planetary mixer) to prepare a paste. The paste was filled into a molding container and polymerized and cured for 60 to 180 minutes at 100–130°C and 1.0–5.0 MPa nitrogen pressure to obtain a block cured body (Examples 1–16 and Comparative Examples 1–5).

[0092] In addition, the components represented by symbols or abbreviations in Tables 3 and 4 are as follows.

[0093] • Silica micro powder: AEROSIL (manufactured by AEROSIL Corporation of Japan; AEROSIL is a registered trademark.)

[0094] • Silane-treated glass: Barium glass powder with surface treated with 8-methacryloyloxyoctyltrimethoxysilane (average particle size: 0.7 μm).

[0095] <Paste viscosity>

[0096] The viscosity of the paste was determined at 25°C with a shear rate of 1 [1 / s] using a rheometer (Anton Paar, MCR 302e).

[0097] <Bending Test>

[0098] Using diamond tools, test pieces measuring 1.2mm × 4.0mm × 14.0mm were cut from the solidified block. All surfaces of the test pieces were then finished with P2000 water-resistant abrasive paper. A three-point bending test was performed using a universal testing machine (Shimadzu AG-Xplus) with a support distance of 12mm and a crosshead speed of 1.0mm / min. The three-point bending strength and flexural modulus were determined.

[0099] The 3-point bending strength is calculated according to the following formula (7).

[0100]

Number 1

[0101]

[0102] In equation (7), F is the maximum load [N] measured in the bending test, S is the distance between the supports [mm], b is the width of the test piece [mm] measured before the test, and h is the thickness of the test piece [mm] measured before the test. Regarding the evaluation of the 3-point bending strength, a 3-point bending strength of 310 MPa or higher is considered good, and a strength less than 310 MPa is considered poor.

[0103] The flexural modulus was calculated from the strain-stress curves obtained from a 3-point bending test using the secant method. The flexural modulus was evaluated as good if it was above 8 GPa, and poor if it was below 8 GPa.

[0104] Machinability

[0105] The contact machinability of the block cured body was confirmed when using a cutting machine (manufactured by GC Corporation, Aadva Harmony WET). The contact machinability was compared with existing dental cutting resin materials (existing block cured body products) to evaluate whether it was the same as existing products.

[0106] Table 1

[0107]

[0108] Table 2

[0109]

[0110] Table 3

[0111]

[0112] Table 4

[0113]

[0114] As shown in Tables 1 and 3, in Examples 1 to 16, the resin blocks obtained by using dental compositions containing polymeric monomers having only one urethane group and inorganic filling materials exhibited good three-point flexural strength and flexural modulus.

[0115] In contrast, as shown in Tables 2 and 4, in Comparative Examples 1-5, the resin blocks obtained using dental compositions that do not contain polymeric monomers having only one urethane group exhibit poor three-point flexural strength. Furthermore, in Comparative Examples 1-2, the flexural modulus is poor.

[0116] The embodiments of the present invention have been described above, but the present invention is not limited to the specific embodiments, and various modifications and alterations can be made within the scope of the invention as described in the claims.

[0117] This application claims priority based on Japanese Patent Application No. 2023-068578, filed on April 19, 2023, the entire contents of which are incorporated herein by reference.

Claims

1. A dental composition comprising: Polymerizable monomers having only one group selected from the group consisting of urethane, urea, and carbonate groups, and inorganic filler materials.

2. A resin material for dental cutting, which is formed by polymerizing and curing the dental composition of claim 1.

3. A method for manufacturing a resin material for dental cutting, comprising polymerizing and curing the dental composition of claim 1.

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