Glass composition for dental use and composition for dental use

Abstract

This glass composition for dental use contains silicon (Si) and cesium (Cs) but is substantially free of sodium (Na), potassium (K), and alkaline earth metals.

Description

Dental glass composition and dental composition

[0001] The present invention relates to a dental glass composition and a dental composition.

[0002] In the dental field, dental glass compositions containing barium are known as fillers (filling materials) to be blended into dental hardenable compositions. Barium-containing glasses (barium glasses) have high X-ray contrast properties and are therefore widely used as raw materials for dental fillers that require high X-ray contrast properties (see, for example, Patent Document 1).

[0003] Patent No. 6346086

[0004] However, conventional barium-containing glasses contain polyvalent metals, and therefore, in dental compositions containing acidic substances such as acidic group-containing polymerizable monomers, the polyvalent metals adsorb or react with the acidic groups, resulting in changes in paste properties and a decrease in adhesive strength, resulting in problems with storage stability.

[0005] An object of the present invention is to provide a dental glass composition which has both high X-ray contrast properties and storage stability in the presence of an acidic substance.

[0006] A dental glass composition according to one embodiment of the present invention contains silicon (Si) and cesium (Cs), and is substantially free of sodium (Na), potassium (K), and alkaline earth metals.

[0007] According to one aspect of the present invention, it is possible to provide a dental glass composition that achieves both high X-ray contrast properties and storage stability in the presence of an acidic substance.

[0008] Hereinafter, embodiments of the present invention will be described in detail.

[0009] <Dental Glass Composition> The dental glass composition according to this embodiment contains silicon (Si) and cesium (Cs).

[0010] Silicon (Si) is contained in the dental glass composition in the form of an oxide of silicon (Si) (silicon oxide (SiO ２ )).

[0011] The content of silicon (Si) is not particularly limited, and is, for example, preferably 10% by mass or more and 80% by mass or less, more preferably 20% by mass or more and 70% by mass or less, and even more preferably 30% by mass or more and 60% by mass or less, calculated as oxide in the dental glass composition.

[0012] A silicon (Si) content of 10% by mass or more in terms of oxide can prevent a decrease in the chemical durability of the glass and devitrification, while a silicon (Si) content of 80% by mass or less in terms of oxide can prevent the glass melt from hardening, making it easier to adjust the viscosity of the dental glass composition and reducing the production cost of the dental glass composition.

[0013] Cesium (Cs) is present in the dental glass composition as an oxide of cesium (Cs) (cesium oxide (Cs ２ Cesium (Cs) is an alkali metal with an atomic number or electron count of 55, and exhibits high radiographic contrast in glasses.

[0014] In this specification, X-ray contrast refers to the property that the shade of an X-ray image changes depending on the amount of X-ray absorption by the object, such as biological tissue or material, making it possible to visualize or distinguish the object.

[0015] In dental treatment, it is necessary to clearly identify the treated area after surgery using dental materials such as dental filling materials, so dental materials are required to have such X-ray contrast properties. In dental materials, the resin matrix is ​​an organic substance and does not have sufficient X-ray contrast properties, so the X-ray contrast properties are provided by inorganic fillers such as glass. Therefore, X-ray contrast properties are an important property for dental glass.

[0016] The content of cesium (Cs) is not particularly limited, and is, for example, 5% by mass or more and 55% by mass or less, preferably 10% by mass or more and 45% by mass or less, and more preferably 20% by mass or more and 35% by mass or less, calculated as oxide in the dental glass composition.

[0017] By setting the content of cesium (Cs) in terms of oxide to 5% by mass or more, the X-ray contrast property of the dental glass composition can be improved, and by setting the content of cesium (Cs) in terms of oxide to 55% by mass or less, the content of silicon (Si) in the dental glass composition can be ensured and a decrease in chemical durability can be suppressed.

[0018] The dental glass composition of this embodiment may further contain boron (B), aluminum (Al), zirconium (Zr), and fluorine (F).

[0019] Boron (B) is contained in the dental glass composition in the form of an oxide of boron (B) (boron oxide (B ２ O ３ )).

[0020] When boron (B) is contained, the content of boron (B) in the dental glass composition is not particularly limited, but is preferably 1% by mass or more and 45% by mass or less, more preferably 5% by mass or more and 35% by mass or less, and even more preferably 10% by mass or more and 25% by mass or less, calculated as the oxide, in the dental glass composition.

[0021] When the content of boron (B) in terms of oxide is 1% by mass or more, the chemical durability of the dental glass composition is improved, the melting point of the glass melt is lowered, and the production of the dental glass composition can be facilitated. Also, when the content of boron (B) in terms of oxide is 45% by mass or less, glass phase separation in the dental glass composition can be suppressed and deviation of the composition due to volatilization can be suppressed.

[0022] Aluminum (Al) is contained in the dental glass composition in the form of an oxide of aluminum (Al) (aluminum oxide (Al ２ O ３ )).

[0023] When aluminum (Al) is contained, the content of aluminum (Al) is not particularly limited, and is, for example, preferably 0.1% by mass or more and 35% by mass or less, more preferably 0.5% by mass or more and 25% by mass or less, and even more preferably 1% by mass or more and 15% by mass or less, calculated as an oxide in the dental glass composition.

[0024] When the content of aluminum (Al) in terms of oxide is 0.1 mass % or more, the chemical durability of the dental glass composition can be improved and devitrification of the glass can be suppressed. Also, when the content of aluminum (Al) in terms of oxide is 35 mass % or less, the melting point of the glass melt of the dental glass composition can be lowered, making it easier to produce the dental glass composition.

[0025] Zirconium (Zr) is contained in the dental glass composition in the form of an oxide of zirconium (ZrO ２ )).

[0026] When zirconium (Zr) is contained, the content of zirconium (Zr) in the dental glass composition is not particularly limited, but is preferably 0.1% by mass or more and 20% by mass or less, more preferably 0.5% by mass or more and 15% by mass or less, and even more preferably 1% by mass or more and 10% by mass or less, calculated as the oxide in the dental glass composition.

[0027] When the zirconium (Zr) content in terms of oxide is 0.1 mass % or more, the chemical durability of the glass can be improved, and the X-ray contrast properties of the resulting glass can be improved. Also, when the zirconium (Zr) content in terms of oxide is 20 mass % or less, the melting point of the glass melt of the dental glass composition can be lowered, and the production of the dental glass composition can be facilitated.

[0028] Fluorine (F) can be present in the dental glass composition as fluoride or a fluoride salt.

[0029] When fluorine (F) is contained, the content of fluorine (F) is not particularly limited, but is preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.5% by mass or more and 8% by mass or less, and even more preferably 1% by mass or more and 5% by mass or less, in terms of simple substance fluorine (F) in the dental glass composition.

[0030] A fluorine (F) content of 0.1% by mass or more reduces the viscosity of the dental glass composition, improving the manufacturability of the dental glass composition and enabling adjustment of the refractive index. A fluorine (F) content of 10% by mass or less prevents devitrification of the glass and suppresses deviation of the composition due to volatilization.

[0031] The dental glass composition according to this embodiment is substantially free of sodium (Na), potassium (K), and alkaline earth metals.

[0032] In this specification, the term "substantially free" means that sodium (Na), potassium (K), and alkaline earth metals are not intentionally included, but unavoidable inclusion of these elements (unavoidable impurities) is permitted.

[0033] Sodium (Na) is an alkali metal with an atomic number or electron count of 11, and is an element that easily reacts with acidic groups such as phosphate groups. Potassium (K) is an alkali metal with an atomic number or electron count of 19, and is an element that easily reacts with acidic groups such as phosphate groups.

[0034] The alkaline earth metal is one or more elements selected from Be (beryllium), magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba), all of which are elements that readily react with acidic groups such as phosphate groups.

[0035] The content of sodium (Na) allowed in the dental glass composition is 1% by mass or less, preferably 0.8% by mass or less, and more preferably 0.5% by mass or less, calculated as an oxide. The sodium (Na) allowed to be contained in the dental glass composition is sodium oxide (Na ２ O).

[0036] If the content of sodium (Na) in terms of oxide exceeds 1 mass %, sodium (Na) reacts with acidic groups such as phosphate groups, which tends to cause poor storage stability in the paste. Therefore, it is preferable that sodium (Na) is substantially not contained.

[0037] In this specification, poor storage stability refers to a change in the properties of a paste obtained by mixing an acidic substance (for example, an acidic group-containing polymerizable monomer) with a dental glass composition.

[0038] The content of potassium (K) allowed in the dental glass composition is 1 mass % or less, preferably 0.8 mass % or less, more preferably 0.5 mass % or less, calculated as oxide. The potassium (K) allowed to be contained in the dental glass composition is potassium oxide (K) in the dental glass composition. ２ O).

[0039] If the content of potassium (K) in terms of oxide exceeds 1 mass %, potassium (K) reacts with acidic groups (phosphate groups) and tends to cause poor storage stability in the paste. Therefore, it is preferable that potassium (K) is substantially not contained.

[0040] The allowable content of alkaline earth metals in the dental glass composition is not particularly limited, and is, for example, 1% by mass or less, preferably 0.8% by mass or less, and more preferably 0.5% by mass or less, calculated as oxide.

[0041] The alkaline earth metals that are permitted to be contained in the dental glass composition may exist in the dental glass composition as oxides of alkaline earth metals, such as beryllium oxide (BeO), magnesium oxide (MgO), calcium oxide (CaO), and strontium oxide (SrO).

[0042] If the content of alkaline earth metals in terms of oxides exceeds 1 mass %, the alkaline earth metals react with acidic groups such as phosphate groups, which tends to cause poor storage stability in the paste. Therefore, it is preferable that the paste is substantially free of alkaline earth metals.

[0043] The alkaline earth metals that are substantially free of in the dental glass composition are, in particular, calcium (Ca), strontium (Sr), and barium (Ba). Of the alkaline earth metals, calcium (Ca), strontium (Sr), and barium (Ba) are more likely to react with acidic groups such as phosphate groups, and therefore, by substantially not including these alkaline earth metals, it is possible to suppress poor storage stability in the paste.

[0044] The dental glass composition of this embodiment may contain other elements as long as the object of the present invention is not impaired. Examples of other elements include zinc (Zn), tin (Sn), lanthanum (La), gadolinium (Gd), and rubidium (Rb), which may be added from the viewpoints of improving X-ray contrast and chemical durability, preventing devitrification, and facilitating the production of the dental glass composition. The other elements may be present as oxides in the dental glass composition. The content of the other elements is not particularly limited, and they may be contained in the dental glass composition at any mass.

[0045] Zinc (Zn) may be present in the dental glass composition as an oxide of zinc (Zn), zinc oxide (ZnO).

[0046] When zinc (Zn) is contained, the content of zinc (Zn) in the dental glass composition is not particularly limited, but is preferably 0.1% by mass or more and 20% by mass or less, more preferably 0.5% by mass or more and 15% by mass or less, and even more preferably 1% by mass or more and 10% by mass or less, calculated as the oxide in the dental glass composition.

[0047] When the zinc (Zn) content in terms of oxide is 0.1 mass % or more, the chemical durability of the dental glass composition can be improved and devitrification of the glass can be suppressed. When the zinc (Zn) content in terms of oxide is 20 mass % or less, devitrification can be prevented without reducing the chemical durability of the resulting glass, and the dental glass composition can be easily produced.

[0048] Lanthanum (La) is contained in dental glass compositions as an oxide of lanthanum (La) (lanthanum oxide (La ２ O ３ )).

[0049] When lanthanum (La) is contained, the content of lanthanum (La) is not particularly limited, but is preferably 1% by mass or more and 40% by mass or less, more preferably 5% by mass or more and 35% by mass or less, and even more preferably 10% by mass or more and 30% by mass or less, calculated as the oxide in the dental glass composition.

[0050] When the content of lanthanum (La) in terms of oxide is 1% by mass or more, the X-ray contrast properties of the resulting glass can be improved, and when the content of lanthanum (La) in terms of oxide is 40% by mass or less, the meltability of the glass can be improved, facilitating the production of a dental glass composition.

[0051] Gadolinium (Gd) is an oxide of gadolinium (Gd) ２ O ３ )).

[0052] When gadolinium (Gd) is contained, the content of gadolinium (Gd) in the dental glass composition is not particularly limited, but is preferably 1% by mass or more and 30% by mass or less, more preferably 3% by mass or more and 25% by mass or less, and even more preferably 5% by mass or more and 20% by mass or less, calculated as the oxide, in the dental glass composition.

[0053] When the content of gadolinium (Gd) in terms of oxide is 1% by mass or more, the X-ray contrast properties of the resulting glass can be improved, and when the content of gadolinium (Gd) in terms of oxide is 30% by mass or less, the meltability of the glass can be improved, facilitating the production of the dental glass composition.

[0054] Rubidium (Rb) is present in the dental glass composition as an oxide of rubidium (Rb) (rubidium oxide (Rb ２ O)).

[0055] The content of rubidium (Rb) is not particularly limited, and is, for example, 3% by mass or more and 30% by mass or less, preferably 5% by mass or more and 25% by mass or less, and more preferably 8% by mass or more and 20% by mass or less, calculated as the oxide in the dental glass composition.

[0056] When the content of rubidium (Rb) in terms of oxide is 3% by mass or more, the X-ray contrast property of the dental glass composition can be improved, and the melting point of the glass melt of the dental glass composition can be lowered, thereby facilitating the production of the dental glass composition. Furthermore, when the content of rubidium (Rb) in terms of oxide is 30% by mass or less, a decrease in chemical durability can be suppressed.

[0057] The dental glass composition of this embodiment may contain other unavoidable impurities, such as nickel (Ni).

[0058] The form of the dental glass composition is not particularly limited, and may be, for example, powder or powdery, plate-like, columnar, thread-like, or fibrous. When the dental glass composition is in powder form, it can be easily blended and mixed with the other components of the dental composition, and the mechanical strength of the dental composition can be increased. Furthermore, when the dental glass composition is in plate-like or columnar form, the mechanical strength and transparency of the dental composition obtained when the dental glass composition is applied to a dental material can be improved.

[0059] When the dental glass composition is in the form of a powder, the particle size of the dental glass composition is not particularly limited, but is preferably 0.01 μm or more and 20 μm or less, more preferably 0.02 μm or more and 10 μm or less, and even more preferably 0.1 μm or more and 1 μm or less in terms of median diameter. Here, the particle size means the average particle size defined by the median diameter.

[0060] When the particle size of the dental glass composition is 0.01 μm or more, the handling of the dental glass composition is improved when the dental glass composition is used as a powder, and when the particle size of the dental glass composition is 20 μm or less, the mechanical strength of the dental composition obtained when the dental glass composition is applied to a dental material is improved.

[0061] The dental glass composition of this embodiment can provide a glass containing the composition with an X-ray contrast property of 300% or more, preferably 400% or more, and more preferably 450% or more, relative to aluminum. In this specification, the X-ray contrast property refers to the X-ray contrast property measured by the X-ray contrast property test method for dental materials in accordance with ISO 4049:2019.

[0062] In this embodiment, a dental glass composition exhibiting good X-ray contrast properties can be provided by making the X-ray contrast properties of the glass containing the dental glass composition 300% or more relative to aluminum. The upper limit of the X-ray contrast properties is not particularly limited, but is preferably 1000% or less, more preferably 900% or less, and even more preferably 800% or less relative to aluminum as a practical range.

[0063] As described above, the dental glass composition of the present embodiment contains silicon (Si) and cesium (Cs), and is substantially free of sodium (Na), potassium (K), and alkaline earth metals. This allows the dental composition to achieve both high X-ray contrast when applied to a dental material and storage stability in the presence of an acidic substance.

[0064] Furthermore, as described above, the alkaline earth metals that the dental glass composition of this embodiment does not substantially contain are calcium (Ca), strontium (Sr), and barium (Ba), and therefore poor storage stability in a paste containing the dental glass composition can be suppressed.

[0065] <Dental Composition> The dental composition according to this embodiment contains the dental glass composition according to this embodiment described above and an acidic group-containing polymerizable monomer.

[0066] The acidic group-containing polymerizable monomer has the function of improving adhesion to tooth structure, ceramics such as zirconia and alumina, which are materials for dental restorations, and alloys containing precious metals. The acidic group-containing polymerizable monomer is not particularly limited, but examples thereof include (meth)acrylates having an acid group.

[0067] The (meth)acrylate monomer having an acid group is not particularly limited, and examples thereof include (meth)acrylate monomers having an acid group such as a phosphate group, a pyrophosphate group, a thiophosphate group, a carboxy group, an acid anhydride residue, a sulfonic acid group, a phosphonic acid group, etc. The (meth)acrylate having an acid group may have a plurality of acid groups.

[0068] Examples of the (meth)acrylate having a phosphate group include 2-(meth)acryloyloxyethyl dihydrogen phosphate, bis[2-(meth)acryloyloxyethyl]hydrogen phosphate, 2-(meth)acryloyloxyethyl phenyl hydrogen phosphate, 6-(meth)acryloyloxyhexyl dihydrogen phosphate, 6-(meth)acryloyloxyhexyl phenyl hydrogen phosphate, 10-(meth)acryloyloxydecyl dihydrogen phosphate, 1,3-di(meth)acryloylpropane-2-dihydrogen phosphate, 1,3-di(meth)acryloylpropane-2-phenyl hydrogen phosphate, and bis[5-{2-(meth)acryloyloxyethoxycarbonyl}heptyl]hydrogen phosphate.

[0069] Examples of (meth)acrylates having a pyrophosphate group include bis[2-(meth)acryloyloxyethyl] pyrophosphate, bis[4-(meth)acryloyloxybutyl] pyrophosphate, bis[6-(meth)acryloyloxyhexyl] pyrophosphate, bis[8-(meth)acryloyloxyoctyl] pyrophosphate, and bis[10-(meth)acryloyloxydecyl] pyrophosphate.

[0070] Examples of (meth)acrylates having a thiophosphate group include 2-(meth)acryloyloxyethyl dihydrogen thiophosphate, 3-(meth)acryloyloxypropyl dihydrogen thiophosphate, 4-(meth)acryloyloxybutyl dihydrogen thiophosphate, 5-(meth)acryloyloxypentyl dihydrogen thiophosphate, 6-(meth)acryloyloxyhexyl dihydrogen thiophosphate, 7-(meth)acryloyloxyheptyl dihydrogen thiophosphate, 8-(meth)acryloyloxyoctyl dihydrogen thiophosphate, 9-(meth)acryloyloxynonyl dihydrogen thiophosphate, 10-(meth)acryloyloxydecyl dihydrogen thiophosphate, and 11-(meth)acryloyloxyundecyl. Examples of the acryloyloxyisopropyl acrylate include 1-(meth)acryloyloxyisopropyl acrylate, ...

[0071] Examples of (meth)acrylates having a carboxy group include 2-methacryloyloxyethyl succinate, 4-(meth)acryloyloxyethyl trimellitic acid, 4-(meth)acryloyloxydecyl trimellitic acid, 11-(meth)acryloyloxy-1,1-undecanedicarboxylic acid, 1,4-di(meth)acryloyloxypyromellitic acid, 2-(meth)acryloyloxyethyl maleic acid, 2-(meth)acryloyloxyethyl phthalic acid, and 2-(meth)acryloyloxyethyl hexahydrophthalic acid.

[0072] Examples of the (meth)acrylate having an acid anhydride residue include 4-(meth)acryloyloxyethyltrimellitic anhydride, 4-(meth)acryloyloxydecyltrimellitic anhydride, and the like.

[0073] Examples of the (meth)acrylate having a sulfonic acid group include 2-(meth)acrylamido-2-methylpropanesulfonic acid, styrenesulfonic acid, and 2-sulfoethyl(meth)acrylate.

[0074] Examples of the (meth)acrylate having a phosphonic acid group include 2-(meth)acryloyloxyethyl phenyl phosphonate, 5-(meth)acryloyloxypentyl-3-phosphonopropionate, 6-(meth)acryloyloxyhexyl-3-phosphonopropionate, 10-(meth)acryloyloxydecyl-3-phosphonopropionate, 6-(meth)acryloyloxyhexyl-3-phosphonoacetate, and 10-(meth)acryloyloxydecyl-3-phosphonoacetate.

[0075] These (meth)acrylate monomers having an acid group may be used alone or in combination of two or more.

[0076] As the (meth)acrylate having an acid group, from the viewpoints of the solubility of the smear layer on the tooth surface of the dental composition, the demineralization of tooth tissue, and particularly the adhesion to enamel, (meth)acrylates having a phosphate group, a thiophosphate group, a carboxy group, or an acid anhydride residue are preferred, and among these, the phosphate group is more preferred.

[0077] Furthermore, among these, 10-methacryloyloxydecyl dihydrogen phosphate (MDP), 10-methacryloyloxydecyl dihydrogen thiophosphate (MDTP), 4-methacryloyloxyethyl trimellitic anhydride (4-META), etc. are preferred from the viewpoint of improving the adhesiveness of the dental composition, with MDP being more preferred.

[0078] The content of the acidic group-containing polymerizable monomer in the dental composition is not particularly limited and can be, for example, 0.1% by mass or more and 20% by mass or less, preferably 1% by mass or more and 15% by mass or less, and more preferably 3% by mass or more and 10% by mass or less.

[0079] When the content of the acidic group-containing polymerizable monomer in the dental composition is 0.1% by mass or more, the adhesiveness of the dental composition to tooth structure is improved, and when the content is 20% by mass or less, the hardening property of the dental composition is improved.

[0080] The dental composition of this embodiment may contain other components as long as the purpose of the present invention is not impaired. Examples of other components contained in the dental composition include a polymerizable monomer having no acid group, a polymerization initiator, a polymerization inhibitor, a filler, and a solvent. Examples of polymerization initiators include chemical polymerization initiators and photopolymerization initiators.

[0081] The polymerizable monomer having no acid group is not particularly limited, and examples thereof include polyfunctional (meth)acrylate compounds, of which bifunctional (meth)acrylate compounds are preferred, such as ethoxylated bisphenol A dimethacrylate, 2,2-bis[4-[2-hydroxy-3-(methacryloyloxy)propyloxy]phenyl]propane, neopentyl glycol dimethacrylate, di-2-methacryloyloxyethyl 2,2,4-trimethylhexamethylene dicarbamate (UDMA), triethylene glycol dimethacrylate (TEGDMA), etc. These bifunctional (meth)acrylate compounds may be used alone or in combination of two or more.

[0082] The content of the polymerizable monomer not having an acid group in the dental composition is not particularly limited, and can be, for example, 1% by mass or more and 40% by mass or less in the dental composition, preferably 3% by mass or more and 35% by mass or less, and more preferably 5% by mass or more and 33% by mass or less.

[0083] When the content of the polymerizable monomer without an acid group in the dental composition is 1 mass % or more, the adhesiveness of the dental composition can be improved, and when the content of the polymerizable monomer without an acid group in the dental composition is 40 mass % or less, the acid reactivity of the dental glass composition in the dental composition can be suppressed, and poor storage stability in the paste can be suppressed.

[0084] The polymerization initiator is not particularly limited, and examples thereof include a chemical polymerization initiator and a photopolymerization initiator.

[0085] The chemical polymerization initiator is not particularly limited, and for example, a thiourea derivative, a vanadium compound, a tertiary amine, or an organic peroxide can be used.

[0086] Thiourea derivatives function as reducing agents among chemical polymerization initiators.

[0087] The thiourea derivative is not particularly limited, and examples thereof include ethylene thiourea, N-methyl thiourea, N-ethyl thiourea, N-propyl thiourea, N-butyl thiourea, N-lauryl thiourea, N-phenyl thiourea, N-cyclohexyl thiourea, N,N-dimethyl thiourea, N,N-diethyl thiourea, N,N-dipropyl thiourea, N,N-dibutyl thiourea, N,N-dilauryl thiourea, N,N-diphenyl thiourea, N,N-dicyclohexyl thiourea, trimethyl thiourea, tetramethyl thiourea, N-acetyl thiourea, N-benzoyl thiourea, 1-allyl-3-(2-hydroxyethyl)-2-thiourea, 1-(2-tetrahydrofurfuryl)-2-thiourea, N-tert-butyl-N'-isopropyl thiourea, and 2-pyridyl thiourea.

[0088] These thiourea derivatives may be used alone or in combination of two or more. Among these, N-benzoylthiourea is preferred in terms of improving the hardening properties of the dental composition.

[0089] The content of the thiourea derivative in the dental composition is not particularly limited, but is preferably from 0.1 to 5% by mass, more preferably from 0.1 to 3% by mass, and even more preferably from 0.1 to 1% by mass. When the content of the thiourea derivative in the dental composition is 0.1% by mass or more, the hardening property of the dental composition is further improved, and when it is 5% by mass or less, the solubility of the thiourea derivative in (meth)acrylate in the dental composition is improved.

[0090] The vanadium compound functions as a reducing agent among chemical polymerization initiators.

[0091] The vanadium compound is not particularly limited, and examples thereof include oxovanadium oxalate, vanadyl acetylacetonate, vanadium acetylacetonate, vanadyl stearate, vanadium naphthenate, and vanadium benzoylacetonate. These vanadium compounds may be used alone or in combination of two or more. Among these, vanadyl acetylacetonate is preferred in terms of the hardening properties of the dental composition.

[0092] The content of the vanadium compound in the dental composition is not particularly limited, but is preferably 0.001% by mass or more and 5% by mass or less, more preferably 0.0015% by mass or more and 1% by mass or less, and even more preferably 0.002% by mass or more and 0.1% by mass or less. When the content of the vanadium compound in the dental composition is 0.001% by mass or more, the hardenability of the dental composition is further improved, and when it is 5% by mass or less, the storage stability of the dental composition is further improved.

[0093] Tertiary amines function as reducing agents among chemical polymerization initiators.

[0094] The tertiary amine is not particularly limited, and examples thereof include tertiary aliphatic amines and tertiary aromatic amines.

[0095] Examples of tertiary aliphatic amines include N,N-dimethylaminoethyl methacrylate and triethanolamine.

[0096] Examples of tertiary aromatic amines include alkyl p-dialkylaminobenzoates, 7-dimethylamino-4-methylcoumarin, N,N-dimethylaniline, N,N-dibenzylaniline, N,N-dimethyl-p-toluidine, N,N-diethyl-p-toluidine, N,N-bis(2-hydroxyethyl)-p-toluidine, N,N,2,4,6-pentamethylaniline, N,N,2,4-tetramethylaniline, and N,N-diethyl-2,4,6-trimethylaniline.

[0097] Of these, the tertiary amine is preferably a tertiary aromatic amine, more preferably an alkyl p-dialkylaminobenzoate.

[0098] Examples of alkyl p-dialkylaminobenzoates include methyl p-dimethylaminobenzoate, ethyl p-dimethylaminobenzoate, propyl p-dimethylaminobenzoate, amyl p-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, ethyl p-diethylaminobenzoate, and propyl p-diethylaminobenzoate.

[0099] These tertiary amines may be used alone or in combination of two or more.

[0100] Among chemical polymerization initiators, organic peroxides function as oxidizing agents.

[0101] Examples of organic peroxides include benzoyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, t-amyl hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, 2,5-dimethyl-2,5-di(hydroperoxy)hexane, p-diisopropylbenzene monohydroperoxide, p-methane hydroperoxide, and pinane hydroperoxide.

[0102] These organic peroxides may be used alone or in combination of two or more. Among these, cumene hydroperoxide is preferred in terms of the hardening properties of the dental composition.

[0103] The content of the organic peroxide in the dental composition is not particularly limited, but is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.05% by mass or more and 5% by mass or less, and even more preferably 0.1% by mass or more and 3% by mass or less. When the content of the organic peroxide in the dental composition is 0.01% by mass or more, the hardening property of the dental composition is further improved, and when it is 10% by mass or less, the working time of the dental composition is extended.

[0104] The photopolymerization initiator is not particularly limited, and examples thereof include camphorquinone (CQ), ethyl 4-dimethylaminobenzoate (EPA), 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO), phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, benzil ketal, diacetyl ketal, benzil dimethyl ketal, benzil diethyl ketal, benzil bis(2-methoxyethyl)ketal, 4,4′-dimethyl(benzyl dimethyl ketal), anthraquinone, 1-chloroanthraquinone, 2-chloroanthraquinone, 1,2-benzanthraquinone, 1-hydroxyanthraquinone, 1-methylanthraquinone, 2-ethylanthraquinone, and 2-ethylanthraquinone. Examples of thioxanthroxanthone include benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzophenone, bis(4-dimethylaminophenyl)ketone, and 4,4'-bis(diethylamino)benzophenone.

[0105] These photopolymerization initiators may be used alone or in combination of two or more. Among these, camphorquinone (CQ), ethyl 4-dimethylaminobenzoate (EPA), and 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO) are preferred in terms of improving the curability of the dental composition.

[0106] The content of the photopolymerization initiator in the dental composition is not particularly limited, but is preferably 0.01% by mass or more and 5% by mass or less, more preferably 0.05% by mass or more and 3% by mass or less, and even more preferably 0.1% by mass or more and 1% by mass or less. When the content of the photopolymerization initiator in the dental composition is 0.01% by mass or more, the hardening property of the dental composition is improved, and when it is 5% by mass or less, the storage stability of the dental composition is improved.

[0107] Examples of the polymerization inhibitor include dibutylhydroxytoluene (2,6-di-tert-butyl-p-cresol), 6-tert-butyl-2,4-xylenol, and 1,4-dihydroxybenzene.

[0108] These polymerization inhibitors may be used alone or in combination of two or more. Among these, dibutylhydroxytoluene and 6-tert-butyl-2,4-xylenol are preferred in terms of improving the hardening properties of the dental composition.

[0109] The content of the polymerization inhibitor in the dental composition is not particularly limited, but is preferably 0.001% by mass or more and 5% by mass or less, more preferably 0.005% by mass or more and 3% by mass or less, and even more preferably 0.01% by mass or more and 1% by mass or less. When the content of the polymerization inhibitor in the dental composition is 0.001% by mass or more, the storage stability of the dental composition is improved, and when the content of the polymerization inhibitor in the dental composition is 5% by mass or less, the hardenability of the dental composition is improved.

[0110] The filler is, for example, an inorganic filler, and examples of the filler include glass, a glass composition, a dental glass composition, and inorganic crystalline substances.

[0111] As described above, the dental composition of this embodiment contains the dental glass composition of this embodiment, and therefore provides the effects of the dental glass composition. That is, a dental composition containing the dental glass composition of this embodiment can achieve both high X-ray contrast and storage stability in the presence of an acidic substance. Furthermore, because the dental composition of this embodiment exhibits good X-ray contrast, it can clearly identify the repaired area in post-treatment diagnosis or examination using X-ray images.

[0112] The dental composition of the present embodiment may be used in any application, including, but not limited to, dental materials that require high X-ray contrast, since the dental composition exhibits high X-ray contrast. Examples of such dental materials include dental composite resins, dental cements, dental adhesives, dental temporary sealing materials, dental primers, dental coating materials, dental hard resins, resin materials for dental cutting, dental temporary restorative materials, dental filling materials, and dentifrices.

[0113] The present invention will be further described below with reference to examples. In the following, numerical values ​​without units or "%" are by mass unless otherwise specified.

[0114] <Glass Preparation> Glasses (Glasses 1 to 8) were prepared with the compositions shown in Table 1. The glass was obtained as a bulk body by placing a raw material batch obtained by mixing various raw materials into a platinum crucible, then placing it in an electric furnace preheated to 1400 to 1600°C for 30 to 60 minutes, and pouring it into a carbon mold. Alternatively, after melting the glass in the same manner, the glass molten liquid was dropped into a water tank to obtain granulated glass. The glass was pulverized in an alumina magnetic mortar to obtain glass powder with a median particle size of 20 to 300 μm.

[0115] The obtained glass bulk was heat-treated in an electric furnace by heating it from room temperature to 600°C at a heating rate of 20°C / min, holding it at 600°C for 30 minutes, and then slowly cooling it to room temperature. The heat-treated glass bulk was sliced ​​to obtain slices.

[0116] <X-ray contrast property> The X-ray contrast property (% of Al) of the obtained glass slices was measured. The X-ray contrast property was measured by the X-ray contrast property test method for dental materials in accordance with ISO 4049:2019. Specifically, the optical density or gray value of a test piece (plate-shaped dental glass composition) having a thickness Ts (unit: mm) was measured. Next, the thickness Ta (unit: mm) of an aluminum plate showing the same optical density or gray value as the test piece having a thickness Ts was determined. The ratio of the thickness Ta to the thickness Ts (unit: % of Al) was used as the value of the X-ray contrast property. The results of the X-ray contrast property are shown in Table 1.

[0117] It should be noted that the silica filler described below was a powder sample and therefore could not be molded into a bulk body, making it impossible to accurately measure the X-ray contrast properties.

[0118]

[0119] <Preparation of Dental Composition (Test Specimen)> The glass or silica filler (RAF1000, manufactured by Tatsumori Co., Ltd.) shown in Table 1 was mixed and stirred with 3-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silane treating agent to obtain an inorganic filler. Furthermore, a polymerizable monomer (polymerizable monomer having no acid group), an acidic substance (polymerizable monomer containing an acidic group), a polymerization initiator, and an inhibitor were kneaded in the compounding ratios shown in Table 2 to prepare an organic component.

[0120] Each of the obtained inorganic fillers was mixed with Aerosil (manufactured by Nippon Aerosil Co., Ltd.) and the organic components shown in Table 2 to prepare dental compositions (test specimens) in the blending ratios shown in Table 3. In Table 3, glasses 1 to 5, 7, and 8 were mixed in a blending ratio of 1, glass 6 in a blending ratio of 2, and the silica filler in a blending ratio of 3.

[0121]

[0122] The abbreviations for the components in Table 2 and the corresponding components are as follows: TEGDMA: triethylene glycol dimethacrylate UDMA: urethane dimethacrylate MDP: 10-methacryloyloxydecyl dihydrogen phosphate CQ: camphorquinone EPA: ethyl 4-dimethylaminobenzoate IA: 6-tert-butyl-2,4-xylenol BHT: dibutylhydroxytoluene

[0123]

[0124] <Storage Stability Test> A storage stability test was performed on the obtained dental composition (test specimen) to confirm its storage stability. The obtained dental composition (test specimen) was filled into a filling syringe and stored in a thermo-humidistat chamber at 37°C and 90% RH. In addition, water (0.8%) equivalent to 3 months of storage at 37°C and 90% RH was added to the paste immediately after preparation. The dental composition (test specimen) immediately after preparation or after the addition of water was polymerized by light irradiation to obtain a hardened product of the dental composition (test specimen) (hardened dental composition).

[0125] <Evaluation Criteria for Storage Stability> The storage stability of dental compositions (test specimens) immediately after production or after a storage stability test was evaluated using the following two methods. The viscosity of the dental composition (test specimen) was evaluated using a rheometer. If the viscosity (mPa·s) of the dental composition (test specimen) after the storage stability test increased by 10% or more compared to that immediately after production, the storage stability was rated as poor. Furthermore, if the formation of salts derived from acidic substances (MDP) and glass eluates (detected as needle-shaped substances in SEM images) was confirmed by scanning electron microscope (SEM) observation of the cured product (dental composition cured product) cured by photopolymerization, the storage stability was rated as poor. Furthermore, if no defects were observed in either SEM observation or rheometer evaluation, the storage stability was rated as good. If defects were confirmed in either one, the storage stability was rated as poor. The evaluation results of the storage stability test are shown in Table 4.

[0126] <Measurement of X-ray contrast property of cured dental composition> The obtained dental composition (test specimen) was cured by photopolymerization to obtain a cured dental composition (cured dental composition), and the X-ray contrast property (% of Al) was measured. The X-ray contrast property was measured using a test method for X-ray contrast property of dental materials in accordance with ISO 4049:2019. Specifically, the optical density or gray value of a test specimen (cured dental composition) with a thickness Ts (unit: mm) was measured. Next, the thickness Ta (unit: mm) of an aluminum plate exhibiting the same optical density or gray value as the test specimen with a thickness Ts was determined. The ratio of the thickness Ta to the thickness Ts (unit: % of Al) was used as the value of X-ray contrast property. Furthermore, a cured dental composition with an X-ray contrast property (unit: % of Al) of 200 or less was determined to be unsuitable.

[0127]

[0128] As can be seen from Tables 1 to 4, dental compositions containing glass that contains silicon (Si) and cesium (Cs) and is substantially free of sodium (Na), potassium (K), and alkaline earth metals have good storage stability and X-ray contrast properties (Examples 1 to 3).

[0129] In contrast, dental compositions formulated with glass or silica fillers that do not satisfy the condition of containing silicon (Si) and cesium (Cs) and being substantially free of sodium (Na), potassium (K), and alkaline earth metals, exhibited poor storage stability and / or X-ray contrast properties (Comparative Examples 1 to 6).

[0130] Although the embodiments of the present invention have been described above, the present invention is not limited to the specific embodiments, and various modifications and changes are possible within the scope of the invention described in the claims.

[0131] This application claims priority based on Japanese Patent Application No. 2023-140970, filed on August 31, 2023, the entire contents of which are incorporated herein by reference.

Claims

1. A dental glass composition comprising silicon (Si) and cesium (Cs), and substantially free of sodium (Na), potassium (K) and alkaline earth metals.

2. A dental glass composition containing silicon (Si) and cesium (Cs), and substantially free of sodium (Na), potassium (K), calcium (Ca), strontium (Sr), and barium (Ba).

3. A dental composition comprising the dental glass composition according to claim 1 or 2 and an acidic group-containing polymerizable monomer.

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