Dental curable composition and method for producing same

Abstract

Provided are: a dental curable composition that contains a radically polymerizable monomer component (A), an inorganic powder / granules (B), and a polymerization initiator (C), the dental curable composition having paste characteristics such as the viscosity decreasing greatly when the composition is heated from room temperature to 42°C, which is thought not to damage dental pulp cells; and a method for producing the dental curable composition. The dental curable composition contains 120-300 parts by mass of an inorganic powder / granules (B1) per 100 parts by mass of (A), in which the amount of monomers having a urethane group is 50 mass% or greater and the amount of monomers having an aromatic ring is less than 30 mass%. In the dental curable composition, (B1) is dispersed in (A) so that the surface of (B1) is in contact with (a1). (B) includes (B1), (B1) being obtained by surface treating the surface of (b1), which has a primary particle size of 200-1000 nm, using a silane coupling agent (D) containing a given proportion of an organic silicon compound "that is a monovalent organic group having an aromatic ring, does not contain any amino groups, and either does not contain any imino groups or hydroxyl groups or contains one of an imino group or a hydroxyl group," such as N-phenyl-3-aminopropyltrimethoxysilane.

Description

Dental hardenable composition and method for producing same

[0001] The present invention relates to a dental hardenable composition and a method for producing the same.

[0002] Composite resins (hereinafter sometimes abbreviated as "CR") used in dental filling treatments are curable compositions containing a monomer component (radical polymerizable monomer component) consisting of a radical polymerizable monomer, inorganic powder particles that function as a filler, and a radical polymerization initiator. When preparing the curable composition, the inorganic powder particles are typically surface-treated in advance with a silane coupling agent to improve the dispersibility of the inorganic powder particles and their adhesion to the resin after curing. The radically polymerizable γ-methacryloyloxypropyltrimethoxysilane is often used as the silane coupling agent (see Patent Document 1).

[0003] In recent years, in restorations using CR, a method (direct bonding) has been often adopted in which the CR is directly filled into a cavity formed in a tooth using a syringe, then shaped and cured. However, the CR used in this method is required to have operability that allows for comfortable filling operations and formability that allows the CR to maintain its shape after molding (until hardening). That is, while high fluidity (low viscosity) makes it easy to fill into the cavity, there is a risk that it will flow out of the cavity if filled up to the occlusal surface. Conversely, CR with low fluidity (high viscosity) makes it easy to reproduce the shape of the occlusal surface, but there is a risk that it will not only require force to fill into the cavity, but also that its adhesion to the cavity floor (cavity compatibility) will be reduced.

[0004] While CRs aiming to achieve both operability and formability have been proposed, they are not necessarily satisfactory at present. For example, Patent Document 2 discloses a dental curable composition containing a predetermined amount of two different sized inorganic fillers treated with a specific silane coupling agent as a direct-filling treatment agent that can be filled directly from a syringe-type container, allowing for easy discharge and suitable formability. While this curable composition exhibits sufficient formability, excellent hardened body strength, and a viscosity that allows for direct filling, it has not been able to achieve high fluidity sufficient to easily reach every corner of even deep cavities. Among dental curable compositions that exhibit good formability, the viscosity is approximately 80 to 650 (Pa·s). Meanwhile, a composite resin used as a backing layer during composite resin layer filling is known as a dental restorative composition that exhibits high fluidity sufficient to easily reach every corner of such deep cavities, and has a viscosity of approximately 7 to 48 (Pa·s) (see Patent Document 3).

[0005] As described above, since the viscosity required for the operability and the viscosity required for the shaping property are different, generally, a hardening paste with different fluidity is used to fill the cavity at each certain depth, and a hardening paste with high fluidity is used to stack the layers from the deepest part, and a hardening paste with low fluidity (hard) is stacked on the final surface layer, thereby performing layer filling. In this way, using different hardening pastes depending on the fluidity requires preparing each fluidity for each color tone, which actually puts a burden on inventory management.

[0006] On the other hand, a method of using a composite resin heater to heat the CR in a syringe container is also known as a method of controlling the fluidity (viscosity) by changing the temperature of a single type of CR. This method takes advantage of the fact that CR generally becomes less viscous, albeit slowly, when heated, and although this varies depending on the manufacturer, composite resin heaters with a heating range of approximately 37°C to 68°C are commercially available.

[0007] Japanese Patent Application Laid-Open No. 63-159214 International Publication No. 2008 / 093596 Pamphlet Japanese Patent Application Laid-Open No. 2001-139411

[0008] Zach. L. et al. , Oral Surg. Oral Med. Oral Pathol. , 1965, 19, 515-530

[0009] When heating CR using a composite resin heater, the heating temperature must take into consideration the burden on the patient. However, since Non-Patent Document 1 shows that dental pulp cells are irreversibly damaged when the temperature rises 5.5°C above body temperature, it is also necessary to consider the impact on dental pulp tissue when heated CR is filled into a deep cavity. Furthermore, the level of viscosity reduction when heated to a temperature not exceeding 5.5°C above body temperature varies depending on the purpose of the CR, and for example, a resin that shows good shaping properties around room temperature (for example, viscosity at 25°C: η ２５ CR adjusted to a relatively high viscosity (e.g., viscosity at 42°C: η ４２ On the other hand, it is preferable to lower the viscosity to a level that shows good fluidity around room temperature (for example, η ２５ In the case of CR, the viscosity is adjusted to a relatively low value (such as 50 to 80 Pa·s) and the shapeability is within an acceptable range. In this case, the fluidity during operation is very good (for example, η ４２ It is preferable to lower the viscosity to a level where the viscosity at 25°C is η ２５ and viscosity at 42 ° C: η ４２ Ratio of: η ２５ / η ４２ However, it can be said that a larger value is preferable.

[0010] However, when the inventors investigated the viscosity change with temperature of existing CRs that show good shaping properties around room temperature, they found that none of them, within the range examined by the inventors, showed fluidity that resulted in good operability when heated to a temperature not exceeding 5.5°C higher than body temperature.

[0011] Therefore, the present invention provides a composition that exhibits good shaping properties around room temperature, and exhibits fluidity that provides good operability when heated to a temperature not exceeding 5.5°C higher than body temperature, and has a viscosity of η ２５ / η ４２ The present invention aims to provide a dental hardenable composition having a high yield and a method for producing the same.

[0012] The present invention solves the above-mentioned problems. In a first aspect, the present invention provides a dental curable composition comprising a radically polymerizable monomer component (A), inorganic powder and granules (B), and a polymerization initiator (C). The radically polymerizable monomer component (A) contains 50% by mass or more of a radically polymerizable monomer (a1) having a urethane group in the molecule and no aromatic ring, and contains no or less than 30% by mass of a radically polymerizable monomer (a2) having an aromatic ring in the molecule. The inorganic powder and granules (B) include inorganic powder and granules (B1) obtained by surface-treating inorganic powder and granules (b1) having an average primary particle diameter of 200 nm to 1,000 nm as measured using a scanning electron microscope (SEM) with a silane coupling agent (D). The content of the inorganic powder and granules (B1) is 120 parts by mass to 300 parts by mass per 100 parts by mass of the radically polymerizable monomer component (A). The silane coupling agent (D) (hereinafter also referred to as "specific silane coupling agent (D)") comprises an organosilicon compound containing 0.5 mol % to 100 mol % of a compound (d1) represented by the following general formula (1): The inorganic powder and granule (B1) is dispersed in the radical polymerizable monomer component (A) so that the surface of the inorganic powder and granule (B1) comes into contact with the radical polymerizable monomer (a1).

[0013]

[0014] (In the formula, X is a hydroxyl group or an alkoxy group having 1 to 4 carbon atoms, n is an integer of 1 to 3, Z is a hydrogen atom, a methyl group, an ethyl group, or a vinyl group, and Y is a monovalent organic group having an aromatic ring, which does not contain an amino group and does not contain either an imino group or a hydroxyl group, or which contains either an imino group or a hydroxyl group.)

[0015] In the dental curable composition of the above form (hereinafter also referred to as "dental curable composition of the present invention"), the inorganic powder and particle (b1) has a specific surface area measured by the BET method of 5 to 15 (m ２ / g), where S is the specific surface area, R is the weight loss (g) per 1 (g) of (B1) when the inorganic powder or particle (B1) is measured using a thermogravimetric differential thermal analyzer (TG-DTA) in a temperature range of 25 to 500 (°C) at a heating rate of 20 (°C / min), and M is the average molecular weight of the specific silane coupling agent (D), which is defined as the sum of the values ​​obtained by dividing the product of the molecular weight and the content (mol %) of each organosilicon compound constituting the specific silane coupling agent (D) by 100, then the following formula is obtained: TQ Ｄ = (R / M) / S = R / (M × S) Ｄ But 6.5 x 10 －６ ~2.0 x 10 －５ (mol / m ２ ) is preferred.

[0016] Also, using a rheometer, the shear rate was 5 (s －１ When the viscosity is measured while raising the temperature from 20 to 60°C at a temperature rise rate of 8°C / min, it is preferable that the viscosity at 20 to 25°C is in the range of 100 to 300 (Pa s), the viscosity at 37 to 42°C is in the range of 10 to 30 (Pa s), and the value obtained by dividing the viscosity at 25°C by the viscosity at 42°C is 5.0 to 20.0.

[0017] A second aspect of the present invention is a method for producing a dental curable composition, comprising the steps of: surface-treating the surface of inorganic powder particles (b1) having an average primary particle diameter of 200 nm to 1,000 nm as measured using a scanning electron microscope (SEM) with a silane coupling agent (D) to obtain inorganic powder particles (B1); and blending a radically polymerizable monomer component (A), inorganic powder particles (B) containing the inorganic powder particles (B1), and a polymerization initiator (C) in an amount of 120 to 300 parts by mass of the inorganic powder particles (B1) per 100 parts by mass of the radically polymerizable monomer component (A). The silane coupling agent (D) is an organosilicon compound containing 0.5 mol % to 100 mol % of a compound (d1) represented by the following general formula (1): The radical polymerizable monomer component (A) contains 50 mass % or more of a radical polymerizable monomer (a1) having a urethane group in the molecule and no aromatic ring, and contains no or less than 30 mass % of a radical polymerizable monomer (a2) having an aromatic ring in the molecule. The inorganic powder / granule (B1) is dispersed in the radical polymerizable monomer component (A) so that its surface comes into contact with the radical polymerizable monomer (a1).

[0018] (In the formula, X is a hydroxyl group or an alkoxy group having from 1 to 4 carbon atoms, n is an integer of from 1 to 3, Z is a hydrogen atom, a methyl group, an ethyl group, or a vinyl group, and Y is a monovalent organic group having an aromatic ring, which does not contain an amino group and does not contain either an imino group or a hydroxyl group, or which contains either an imino group or a hydroxyl group.)

[0019] The viscosity of the dental hardenable composition of the present invention can be reversibly controlled by heating and cooling. For example, slight heating not exceeding 42°C significantly reduces the viscosity, facilitating filling into cavities. Cooling increases the viscosity, improving shaping properties. ２５ / η ４２ Therefore, the dental curable composition of the present invention is particularly suitable as a CR for direct bonding using a composite resin heater.

[0020] This figure is a graph showing the temperature dependence of viscosity of the curable composition P1 obtained in Example 1 and the curable composition CP1 obtained in Comparative Example 1. The two regions surrounded by dotted lines in the graph represent the region where the viscosity is in the range of 100 to 300 (Pa s) at 20 to 25 (°C) and the region where the viscosity is in the range of 10 to 30 (Pa s) at 37 to 42 (°C), respectively.

[0021] The dental hardenable composition of the present invention has the above-mentioned unique temperature dependency of viscosity. The mechanism by which such viscosity characteristics (temperature dependency of viscosity or fluidity) are obtained is not necessarily clear, and the present invention is not bound by any theory, but the present inventors believe as follows.

[0022] That is, the dental curable composition of the present invention has the property that the viscosity changes greatly by heating and cooling, and it is considered that this is due to the temperature-dependent change in the state of interaction between the radical polymerizable monomer (a1) in the radical polymerizable monomer component (A) and the specific silane coupling agent (D) present on the surface of the inorganic powder and particle (B1).Specifically, at low temperatures, the interaction between the urethane group in the radical polymerizable monomer (a1) and the π electron of the aromatic ring in the organosilicon compound (d1) contained in (D) or hydrophobic interaction occurs, generating bonding force, and heating causes the thermal motion of molecules, causing this interaction (bonding force) to disappear or weaken, resulting in viscosity change.

[0023] Furthermore, according to the investigations of the present inventors, it was surprisingly found that the temperature dependence of the above-mentioned interaction is extremely sensitive to the surrounding environment of the aromatic ring in the aromatic ring-containing organosilicon compound (d1), which is an essential component of the specific silane coupling agent (D). As shown in Comparative Examples 11 and 12 described below, when an organosilicon compound having two or more hydrogen atoms with hydrogen bonding properties, such as hydrogen bonded to an oxygen atom or hydrogen bonded to a nitrogen atom, is used instead of (d1) (for example, when an organosilicon compound having one or more amino groups or two or more groups selected from an imino group and a hydroxyl group is used near the aromatic ring), a sufficient decrease in viscosity does not occur even when heated to 37 to 42 ° C.

[0024] On the other hand, with regard to (A), the effect is exhibited if (a1) is the main component, but as shown in Comparative Example 5, when the radical polymerizable monomer contains 30 mass% or more of the radical polymerizable monomer (a2) having an aromatic ring in the molecule, π-π stacking occurs between the aromatic ring of (a2) and the aromatic ring of (d1), and the interaction (bonding strength) does not weaken even when heated, and therefore, sufficient viscosity reduction does not occur even when heated to 37-42°C.

[0025] As described above, it is believed that the dental hardenable composition of the present invention, whose composition satisfies the above-mentioned conditions, weakens the above-mentioned interaction due to slight differences in environmental temperature, thereby achieving the above-mentioned effects.

[0026] Each component of the dental curable composition of the present invention will be described in detail below. In this specification, unless otherwise specified, the expression "x to y" using numerical values ​​x and y means "greater than or equal to x and less than or equal to y." In such an expression, when a unit is assigned only to the numerical value y, the unit also applies to the numerical value x. Furthermore, in this specification, the term "(meth)acrylic" means both "acrylic" and "methacrylic." Similarly, the term "(meth)acrylate" means both "acrylate" and "methacrylate," and the term "(meth)acryloyl" means both "acryloyl" and "methacryloyl."

[0027] 1. Radically Polymerizable Monomer Component (A) The radically polymerizable monomer component (A) refers to a component consisting of a compound (monomer compound) having a radically polymerizable group, such as a (meth)acryloyl group, a (meth)acrylamide group, or a vinyl group, in its molecule. In the dental curable composition of the present invention, the radically polymerizable monomer component (A) must contain 50% by mass or more of a radically polymerizable monomer (a1) having a urethane group (—NH—C(═O)—O— in its molecule and no aromatic ring (hereinafter also referred to as an “aromatic ring-free urethane-based monomer”), and must not contain a radically polymerizable monomer (a2) having an aromatic ring in its molecule (hereinafter also referred to as an “aromatic ring-containing monomer”), or, if it does contain one, the content of such a radically polymerizable monomer is less than 30% by mass. The term “aromatic ring” refers to an aromatic cyclic structure such as a benzene ring, a naphthalene ring, or an anthracene ring.

[0028] If the content of the aromatic ring-free urethane-based monomer (a1) is less than 50% by mass, the interaction with the inorganic powder (b1) described below will be insufficient, and the effects of the present invention will not be achieved. Furthermore, if the content of the aromatic ring-containing monomer (a2) is 30% by mass or more, the interaction with the inorganic powder (b1) described below will be too strong, and the effects of the present invention will not be achieved. To further demonstrate the effects of the present invention, the content of the aromatic ring-free urethane-based monomer (a1) is preferably 55 to 85% by mass, and particularly preferably 60 to 80% by mass. Furthermore, the content of the aromatic ring-containing monomer (a2) is preferably 20% by mass or less, and more preferably 10% by mass or less.

[0029] As the monomer compound constituting (A), it is preferable to use a (meth)acrylate having a (meth)acryloyl group as the radical polymerizable group, because this makes it easy to control the polymerization rate. Furthermore, in order to improve the physical properties of the curable composition after curing, it is preferable to have multiple radical polymerizable groups so that a crosslinked structure can be introduced. From the viewpoints of final strength and polymerization shrinkage, it is preferable to have 2 to 4 radical polymerizable groups, and more preferably 2 to 3 radical polymerizable groups, in one molecule.

[0030] As the non-aromatic ring-containing urethane-based monomer (a1), any monomer compound satisfying the above conditions can be used without particular limitation, but it is preferable to use a (meth)acrylate having 2 to 3 urethane groups per molecule. An example of a suitable non-aromatic ring-containing urethane-based monomer (a1) is 1,6-bis(methacrylethyloxycarbonylamino)trimethylhexane.

[0031] As the aromatic ring-containing monomer (a2), any monomer compound satisfying the above conditions can be used without particular limitation, but it is preferable to use a (meth)acrylate having one or two aromatic rings per molecule. Suitable examples of the aromatic ring-containing monomer (a2) include bisphenol A polyethoxydimethacrylate and bisphenol A glycidyl dimethacrylate.

[0032] As the radically polymerizable monomer component (A), monomer compounds other than the aromatic ring-free urethane monomer (a1) and the aromatic ring-containing monomer (a2) (hereinafter also referred to as "other monomers") can be used, provided that they satisfy the above conditions. Examples of such other monomers include triethylene glycol dimethacrylate and 1,9-nonamethylenediol dimethacrylate.

[0033] The viscosity of the polymerizable monomer component (A) is not particularly limited, but is preferably 2.0 to 10,000 (mPa·s) at 25 (°C), and from the viewpoint of the operability of the curable composition, is particularly preferably 20 to 5,000 (mPa·s).

[0034] 2. Inorganic Powder and Particles (B) The dental curable composition of the present invention contains inorganic powder and particles (B), similar to conventional CRs. Materials for the inorganic powder and particles (B) that are commonly used in dental curable compositions as inorganic fillers can be used without limitation. Specific examples include powder and particles composed of particles such as amorphous silica, silica-titanium group oxide composite oxide particles (silica-zirconia, silica-titania, etc.), quartz, alumina, barium glass, zirconia, titania, lanthanoid oxide, ytterbium fluoride, and colloidal silica. Among these, silica-titanium group oxide composite oxide particles are preferred because their refractive index can be easily adjusted.

[0035] The inorganic powder (B) may contain a certain amount of inorganic powder (B1) described later, and may contain inorganic powder other than (B1). The amount of the inorganic powder other than (B1) is determined by a rheometer in the dental curable composition of the present invention at a shear rate of 5 (s －１ When viscosity measurement is performed while raising the temperature from 20 to 60°C at a temperature rise rate of 8°C / min, the amount is preferably such that the viscosity at 20 to 25°C is in the range of 100 to 300 (Pa s).

[0036] 3. Inorganic Powder and Particles (B1) In order to achieve the effects of the present invention, the dental curable composition of the present invention must contain, as the inorganic powder and particle (B), 120 to 300 parts by mass of inorganic powder and particle (B1) obtained by surface-treating inorganic powder and particle (b1) having an average primary particle diameter of 200 to 1,000 nm as measured using a scanning electron microscope (SEM) with a specific silane coupling agent (D) described below, per 100 parts by mass of the radical polymerizable monomer component (monomer component consisting of a radical polymerizable monomer) (A). Furthermore, in order to achieve the effects of the present invention, the inorganic powder and particle (B1) must be dispersed in the radical polymerizable monomer component (monomer component consisting of a radical polymerizable monomer) (A) so that its surface comes into contact with the radical polymerizable monomer (a1).

[0037] For this reason, in the present invention, the inorganic powder and granules (B) include inorganic powder and granules (B1) obtained by surface-treating the surfaces of inorganic powder and granules (b1) having an average primary particle diameter of 200 nm to 1,000 nm as measured using a scanning electron microscope (SEM) with a silane coupling agent (D). The content of the inorganic powder and granules (B1) is 120 parts by mass to 300 parts by mass per 100 parts by mass of the radical polymerizable monomer component (A). The silane coupling agent (D) is an organosilicon compound containing 0.5 mol % to 100 mol % of a compound (d1) represented by the following general formula (1). The inorganic powder and granules (B1) are dispersed in the radical polymerizable monomer component (A) so that their surfaces come into contact with the radical polymerizable monomer (a1). In the present invention, an organic residue derived from the silane coupling agent (D) is introduced onto the surface of the surface-treated inorganic powder (B1) of the present invention, and the organic residue and the radical polymerizable monomer (a1) are in direct contact with each other. This results in an appropriate interaction between the surface-treated surface of (B1) and (a1), which can promote a decrease in viscosity upon heating compared to when such an interaction does not exist.

[0038] In contrast, inorganic powder particles (B) that serve as inorganic fillers in dental curable compositions are generally sometimes formulated as so-called organic-inorganic composite powder particles (organic-inorganic composite fillers) composed of particles made of a composite compound with a resin. However, the surfaces of the inorganic powder particles that constitute the organic-inorganic composite powder particles are covered with resin, and therefore do not come into contact with the radically polymerizable monomer (a1), and therefore do not contribute to the effects. Therefore, even if inorganic powder particles having an average primary particle size of 200 to 1,000 nm are surface-treated with a specific silane coupling agent (D) composed of an organosilicon compound, those that are made into organic-inorganic composite powder particles do not fall under the category of the inorganic powder particles (B1).

[0039] In addition to (D), the organosilicon compounds constituting general silane coupling agents (D) have a structure in which a silanol group (a hydroxyl group bonded to a silicon atom) or a group that forms a silanol group upon hydrolysis, and an organic residue other than these are bonded to a silicon atom, and during surface treatment, the hydroxyl groups present on the surface of the inorganic particles and the silanol groups or groups that form silanol groups upon hydrolysis condense to form siloxane bonds, and the organic residues are bonded to the surfaces of the inorganic particles via the siloxane bonds. Therefore, the inorganic powder granules (B1) can be said to be inorganic powder granules having an average primary particle diameter of 200 to 1000 nm, in which the organic residues of the organosilicon compound constituting the silane coupling agent (D) are bonded via siloxane bonds to the surfaces of the primary particles constituting the inorganic powder granules. However, during the treatment, silanol groups or groups that form silanol groups upon hydrolysis may condense with each other, or some may remain unreacted, and it is substantially impossible to confirm the state of bonding by analysis. Therefore, in this specification, the inorganic powder granules (B1) are defined using the expression "inorganic powder granules surface-treated with a silane coupling agent (D) composed of an organosilicon compound."

[0040] As described above, the average primary particle diameter of the inorganic powder or granule (B1) is 200 to 1000 nm. The average primary particle diameter is measured using a scanning electron microscope. Specifically, a photograph of the inorganic powder or granule is taken using a scanning electron microscope, and the primary particle diameter (maximum diameter): x of all primary particles (number of particles: n, which is 30 or more) observed within a unit field of view of the photograph is calculated. ｉ (i is an integer from 1 to n representing the number of each particle) are measured, and the sum: Σx ｉ is divided by the number of observed particles: n: (Σx ｉ ) / n.

[0041] If the average primary particle diameter of the inorganic powder (B1) is smaller than 200 nm, the viscosity of the dental curable composition of the present invention will be high, whereas if the particle diameter is larger than 1000 nm, the viscosity will be too low to obtain the effects of the present invention. From the viewpoint of viscosity adjustment, the average primary particle diameter is preferably in the range of 250 to 700 nm, and more preferably in the range of 300 to 500 nm.

[0042] The material of the inorganic particles constituting the inorganic powder (B1) is the same as that of (B), and silica-titanium group oxide composite oxide particles are preferred because the refractive index can be easily adjusted. Furthermore, the inorganic particles constituting the inorganic powder (B1) may be surface-coated with silica because this can increase the amount of treatment (amount of surface-bonded (D)) when surface-treated with the silane coupling agent (D).

[0043] Regarding the refractive index of the inorganic particles, from the viewpoint of the color tone of the dental curable composition, the difference between the refractive index of the polymer of the polymerizable monomer component (A) at 25°C and the refractive index of the inorganic powder and granules (B) at 25°C is preferably 0.001 or more and 0.1 or less, and more preferably 0.002 or more and 0.08 or less.

[0044] There are no particular restrictions on the shape of the primary particles constituting the inorganic powder or particle (B1). However, the primary particles are preferably spherical or nearly spherical, because this makes it easier to increase the specific surface area and to achieve the effects of the present invention. Specifically, the primary particles preferably have an average uniformity of 0.6 or more, more preferably 0.8 or more, calculated by dividing the particle diameter in a direction perpendicular to the maximum diameter by the maximum diameter.

[0045] Incidentally, known examples of "inorganic spherical powder particles composed of spherical or nearly spherical inorganic particles" include those obtained by the so-called sol-gel method, and the inorganic spherical powder particles obtained by this method have a very sharp particle size distribution. Therefore, when the average primary particle diameter is measured by the SEM method, if n is 30 or more, the determined value can be used as the overall average primary particle diameter. When such inorganic powder particles with a sharp particle size distribution are used, (B1) may be a mixture of multiple inorganic powder particles with different average primary particle diameters or types (materials), provided that the overall average primary particle diameter satisfies the condition that the average primary particle diameter is 200 to 1,000 nm. In fact, from the viewpoint of the ease of use of the dental curable composition of the present invention, a mixture of inorganic powder particles with different average primary particle diameters is preferred.

[0046] Furthermore, when the surface is treated with the silane coupling agent (D), the amount of treatment (the amount of (D) bonded to the surface) increases, and aggregation becomes less likely to occur, and from the viewpoint of making it easier to obtain the effects of the present invention, the specific surface area of ​​the inorganic powder or particle (b1) before the surface treatment is preferably 5 to 15 (m ２ / g) Here, the specific surface area of ​​the inorganic powder or particle means the specific surface area measured by the BET method.

[0047] In order to obtain the effects of the present invention, the inorganic powder (B1) must be surface-treated with a silane coupling agent (D) containing a predetermined amount of a specific organosilicon compound (d1) described later. In this case, the surface treatment amount of (D) per unit area of ​​the inorganic powder (B1) is: TQ Ｄ is 5.0 －６ ~2.0 x 10 －５ (mol / m ２ ), and 6.5 × 10 －６ ~2.0 x 10 －５ (mol / m ２ ), and particularly 7.0 × 10 －６ ~1.2 × 10 －５ (mol / m ２ ) is more preferable. Ｄis a value obtained by measuring the surface-treated powder / granule (b1) using a thermogravimetric differential thermal analyzer (TG-DTA) at a temperature range of 25°C to 500°C and a heating rate of 20°C / min. R is the weight loss rate (g / g) that represents the weight loss (g) per 1 (g) of (B1), and the specific surface area: (m ２ / g) is S, and the average molecular weight of (D) is defined as the sum of the values ​​obtained by dividing the product of the molecular weight and the content (mol %) of each organosilicon compound constituting the silane coupling agent (D) by 100, the formula: TQ Ｄ = (R / M) / S = R / (M × S), and as can be seen from the formula, the surface treatment amount per unit area (mol / m) of (D) in the inorganic powder or particle (B) is ２ ) corresponds to

[0048] The method for preparing the inorganic powder (B1) (surface treatment method) will be described in detail after the explanation of the silane coupling agent (D).

[0049] 4. Specific Silane Coupling Agent (D) The inorganic powder (B1) is obtained by surface-treating untreated inorganic powder (B) with a specific silane coupling agent (D) consisting of an organosilicon compound, and 0.5 to 100 mol % of the organosilicon compound constituting the specific silane coupling agent (D) used here must be compound (d1) represented by the following general formula (1). From the viewpoint of effectiveness, the content of (d1) in (D) is more preferably 1.0 mol % or more and 95 mol % or less, and even more preferably 5 mol % or more and 90 mol % or less.

[0050]

[0051] In the general formula (1), X is a hydroxyl group (—OH) or an alkoxy group having 1 to 4 carbon atoms, and n is an integer of 1 to 3. Z is a hydrogen atom, a methyl group, an ethyl group, or a vinyl group. Y has an aromatic ring and an amino group (—NH ２) and contains no or one substituent consisting of an imino group (=NH and >NH, sometimes referred to as a secondary amino group) and a hydroxyl group (-OH). That is, Y is a monovalent organic group having an aromatic ring (which may contain a heteroatom), does not contain an amino group, and contains neither an imino group nor a hydroxyl group, or contains one of either an imino group or a hydroxyl group. This allows a sufficient decrease in viscosity when the dental curable composition of the present invention is heated to 37 to 42°C. The imino group may be contained in the form of an amide bond, a urethane bond, or a urea bond, and the hydroxyl group may be contained in the form of a carboxyl group.

[0052] The group -Y is preferably a group represented by the following general formula (2).

[0053]

[0054] In the above formula (2), L represents a simple bond; an alkylene group having 1 to 20 carbon atoms; or a group in which two alkylene groups having 1 to 10 carbon atoms, each of which may have different carbon atoms, are bonded via -NH-, -NH-C(=O)-, or -NH-C(=O)-O-; M represents an alkyl group having 1 to 3 carbon atoms or a halogen atom; and m represents an integer of 0 to 2.

[0055] The group -Y, particularly the group -L in the above formula (2), is -NH ２ or when the dental hardenable composition of the present invention contains two or more groups: -NH- and / or -OH, the viscosity does not decrease sufficiently when the dental hardenable composition of the present invention is heated to 37 to 42°C.

[0056] Suitable examples of (d1) include N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, benzyl-3-(3-(trimethoxysilyl)propyl)carbamate, and benzyl-3-(3-(triethoxysilyl)propyl)carbamate.

[0057] The organosilicon compound other than (d1) constituting the silane coupling agent (D) is not particularly limited as long as it is an organosilicon compound other than (d1) that functions as the silane coupling agent (D), but is preferably an alkoxysilane compound because the reaction rate during surface treatment is comparable to that of (d1). For example, when (d1) is one of the preferred compounds described above, γ-methacryloyloxypropyltrimethoxysilane, which is commonly used as a surface treatment agent for inorganic fillers in dental curable compositions, is preferably used.

[0058] 5. Method for preparing inorganic powder particles (B1) (surface treatment method) As a method for surface-treating inorganic powder particles having an average primary particle diameter of 200 to 1000 nm with the specific silane coupling agent (D) to prepare surface-treated inorganic powder particles (B1), either a wet treatment method or a dry treatment method may be used, but from the viewpoint of ease of uniform surface treatment, a wet treatment method is preferably used. Here, the wet treatment method is a method, as described, for example, in JP 2008-31309 A, in which a silane coupling agent is added to and mixed with a dispersion in which an inorganic powder particle to be treated is dispersed in an organic solvent in which an amine that functions as a catalyst is dissolved, and the silane coupling agent is hydrolyzed and dehydration-condensed with the inorganic powder particle surface silanol groups, followed by distilling off the organic solvent under reduced pressure and further drying under reduced pressure.

[0059] At this time, the amount of inorganic powder (b1) to be treated is W (g), the specific surface area is S (m ２ / g), the average molecular weight of the specific silane coupling agent (D) used: M, and the amount of (D) used per unit area of ​​the inorganic powder / particle: UQ Ｄ = (W / M) / S = W / (M x S) and the target processing volume: TQ Ｄ = Ratio of R / (M × S): UQ Ｄ / TQ Ｄ = W / R is usually in the range of 1.5 to 3.0 (the loading ratio of (D) to (b1): 100 x R / W is about 33 to 67%). Therefore, if the amount of (D) to be used is determined based on this, the TQ Ｄ It is possible to strictly control TQ ＤIf you want to control TQ, you can carry out a preliminary experiment under the conditions you will actually use and determine W from W / R. Also, it is better to divide (D) into multiple steps and perform surface treatment in stages to reduce TQ. Ｄ That is, it is preferable to add a part of (D) to a dispersion of inorganic powder containing an amine, remove the organic solvent, dry under reduced pressure, and then disperse the obtained surface-treated powder again in the organic solvent together with the amine, and then add the remaining amount of (D) to perform treatment, since this method increases the treatment amount compared to adding the entire amount of (D) at once.

[0060] Even when (D) is composed of different organosilicon compounds, the reactivity remains almost unchanged if these organosilicon compounds are tri-lower alkoxysilane compounds such as trimethoxysilane or triethoxysilane. Therefore, even if these compounds are used in the form of a mixture and treated (reacted) simultaneously, the composition of the groups derived from the organosilicon compound present on the surface of the inorganic powder particles (B) after treatment will correspond to the composition of (D). Incidentally, when the present inventors confirmed using a wet treatment method under the same conditions, the reactivity was approximately 90% when N-phenyl-3-aminopropyltrimethoxysilane or methyltrimethoxysilane was treated alone. Therefore, when using a wet treatment method, for example, a mixture of the organosilicon compounds may be added all at once to a dispersion of inorganic powder particles containing an amine, or the organosilicon compounds may be added sequentially and reacted. In either case, the amount of the surface treatment agent present will depend on the charge ratio.

[0061] When (D) is composed of a plurality of organosilicon compounds with significantly different structures, it is preferable to check the reactivity of each organosilicon compound in advance, and if the reactivity is significantly different, to treat (react) them sequentially, from the viewpoint of easily obtaining a uniform surface treatment state. For example, when a wet treatment method is adopted, it is preferable to add the organosilicon compounds sequentially to a dispersion of inorganic powder containing an amine and react them. Furthermore, it is more preferable to remove the organic solvent and dry under reduced pressure each time the organic solvent is added, and the obtained surface-treated powder is dispersed again in the organic solvent together with the amine, and then add the next organosilicon compound and react.

[0062] 6. Powders and granules other than (B1) The dental curable composition of the present invention may contain powders and granules other than the inorganic powder and granules (B1) as long as the effects of the present invention are not impaired. Examples of powders and granules other than the inorganic powder and granules (B1) include inorganic powders and granules other than (B1) and organic-inorganic composite powders (DF). Examples of inorganic powders and granules other than (B1) include (B2) to (B7) shown below. B2: Inorganic powder and granules having an average primary particle diameter of 200 to 1000 nm, which have been treated with a surface treatment agent other than the specific silane coupling agent (D). B3: Inorganic powder and granules having an average primary particle diameter of less than 200 nm, which have been surface treated with the specific silane coupling agent (D). B4: Inorganic powder and granules having an average primary particle diameter of more than 1000 nm, which have been surface treated with the specific silane coupling agent (D). B5: Inorganic powder and granules having an average primary particle diameter of less than 200 nm, which have been treated with a surface treatment agent other than the specific silane coupling agent (D). B6: Inorganic powder and granules having an average primary particle diameter of more than 1000 nm, which have been treated with a surface treatment agent other than the specific silane coupling agent (D). B7: Inorganic powder and granules that have not been surface treated.

[0063] For the reason that a dental curable composition exhibiting the formability and good operability of a CR can be obtained while maintaining the effects of the present invention, the total amount of inorganic powder particles other than (B1) is preferably 20 parts by mass or less, particularly 10 parts by mass or less, per 100 parts by mass of the radical polymerizable monomer component (A).

[0064] 7. Polymerization initiator (C) As the polymerization initiator, those used in dental curable compositions such as CR can be used without any particular limitation. From the viewpoint of suitability for use in the oral cavity, a photopolymerization initiator or a chemical polymerization initiator composition is preferred, and from the viewpoint of simplicity without the need for a mixing operation, a photopolymerization initiator is preferred.

[0065] Examples of the photopolymerization initiator include benzoin alkyl ethers such as benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether; benzil ketals such as benzil dimethyl ketal and benzil diethyl ketal; benzophenones such as benzophenone, 4,4'-dimethylbenzophenone, and 4-methacryloxybenzophenone; α-diketones such as diacetyl, 2,3-pentanedione benzyl, camphorquinone, 9,10-phenanthraquinone, and 9,10-anthraquinone; thioxanthone compounds such as 2,4-diethoxythioxanthone, 2-chlorothioxanthone, and methylthioxanthone; Examples of suitable phosphine oxides include bisacylphosphine oxides such as bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0066] Incidentally, a reducing agent is often added to the photopolymerization initiator, and examples thereof include tertiary amines such as 2-(dimethylamino)ethyl methacrylate, ethyl 4-dimethylaminobenzoate (ethyl p-N,N-dimethylaminobenzoate), and N-methyldiethanolamine; aldehydes such as lauryl aldehyde, dimethylaminobenzaldehyde, and terephthalaldehyde; and sulfur-containing compounds such as 2-mercaptobenzoxazole, 1-decanethiol, thiosalicylic acid, and thiobenzoic acid.

[0067] The amount of the polymerization initiator used is usually 0.05 to 1.0 part by mass per 100 parts by weight of the polymerizable monomer.

[0068] 8. Other Additives In addition to the above components (A) to (C), other known additives may be blended into the dental curable composition of the present invention, provided that the effects of the composition are not impaired. Specific examples include polymerization inhibitors, ultraviolet absorbers, and photoacid generators.

[0069] 9. Manufacturing Method and Use of Dental Curable Composition of the Present Invention The manufacturing method of the dental curable composition of the present invention includes the steps of: surface-treating the surface of the inorganic powder granules (b1) with the silane coupling agent (D) to obtain inorganic powder granules (B1); and blending the radical polymerizable monomer component (A), the inorganic powder granules (B) containing the inorganic powder granules (B1), and the polymerization initiator (C) in an amount of 120 to 300 parts by mass of the inorganic powder granules (B1) per 100 parts by mass of the radical polymerizable monomer component (A). In the dental curable composition obtained by the above manufacturing method, the inorganic powder granules (B1) are dispersed in the radical polymerizable monomer component (A) so that their surfaces are in contact with the radical polymerizable monomer (a1). This results in a dental curable composition with excellent operability and formability.

[0070] The method for producing the dental curable composition of the present invention is not particularly limited, and any known method for producing a dental curable composition may be appropriately adopted. For example, as described in JP 2013-014690 A, a mixture of a polymerizable monomer (A), a polymerization initiator (C), and other known additives may be added to a weighed-out predetermined amount of inorganic powder or particle (B1), and the mixture may be kneaded.

[0071] The obtained dental hardenable composition was subjected to a shear rate of 5 (s －１ When the viscosity is measured while raising the temperature from 20 to 60°C at a temperature rise rate of 8°C / min, it is preferable that the viscosity at 20 to 25°C is in the range of 100 to 300 (Pa s), the viscosity at 37 to 42°C is in the range of 10 to 30 (Pa s), and the value obtained by dividing the viscosity at 25°C by the viscosity at 42°C is 5.0 or more.

[0072] The viscosity of the dental hardenable composition of the present invention was measured using a rheometer at a shear rate of 5 (s －１The viscosity is measured continuously while raising the temperature from 20 to 60°C under the conditions of a temperature rise rate of 8°C / min. During this process, viscosities at 20°C, 25°C, 37°C, and 42°C can be obtained. There are no limitations on the rheometer as long as it is capable of performing the above measurements, but a rheometer MCR302 (manufactured by Anton Paar) or the like is used.

[0073] The viscosity at 20 to 25°C corresponds to the viscosity at the time of shaping, and is preferably in the range of 100 to 300 (Pa·s), and more preferably in the range of 150 to 250 (Pa·s). The viscosity at 37 to 42°C corresponds to the viscosity at the time of filling, and is preferably in the range of 10 to 30 (Pa·s), and more preferably in the range of 12 to 20 (Pa·s).

[0074] The dental curable composition of the present invention preferably has a viscosity at 25°C divided by the viscosity at 42°C of 5.0 to 20.0. The larger this value, the greater the change in viscosity at around body temperature (37°C), making it easier to change the viscosity. On the other hand, if this value is too large, unintended viscosity changes are more likely to occur. Therefore, the value is more preferably 6.5 to 15.0.

[0075] The dental curable composition of the present invention is particularly suitable for use as a dental filling and restorative material, such as a photocurable composite resin, but is not limited thereto and can also be used for other purposes, such as dental cement and restorative material for core construction.

[0076] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples.

[0077] 1. The radical polymerizable monomers, polymerization initiators, organosilicon compounds, etc. used in each of the Examples and Comparative Examples and their abbreviations are shown below.

[0078] (1) Polymerizable Monomers <Aromatic Ring-Free Urethane Monomer (a1)> UDMA: 1,6-bis(methacrylethyloxycarbonylamino)trimethylhexane <Aromatic Ring-Containing Monomer (a2)> D-2.6E: Bisphenol A polyethoxydimethacrylate bis-GMA: Bisphenol A glycidyl dimethacrylate <Other Monomers> 3G: Triethylene glycol dimethacrylate ND: 1,9-nonamethylenediol dimethacrylate

[0079] (2) Polymerization initiator (C) CQ: camphorquinone DMBE: ethyl p-N,N-dimethylaminobenzoate

[0080] (3) Organosilicon Compounds (Silane Coupling Agents) <Organosilicon Compounds (d1)> KBM-573: N-phenyl-3-aminopropyltrimethoxysilane KBM-103: phenyltrimethoxysilane ST-1: benzyl-3-(3-(triethoxysilyl)propyl)carbamate KBM-1403: p-thrityltrimethoxysilane The structures, molecular weights, and reactivity of these organosilicon compounds are shown below.

[0081]

[0082] The reaction rate was calculated by using a single organosilicon compound of 2.1 × 10 as the silane coupling agent (D) in the surface treatment during the preparation of inorganic powder F1 described later. ―３ The reaction rate is determined from the TG-DTA analysis results of the surface-treated inorganic powder obtained when the treatment was carried out using 100 moles of ST-1. ST-1 was synthesized by the method shown below.

[0083] [Synthesis of ST-1] First, 10.8 g of benzyl alcohol (0.10 mol), 0.03 g of dibutyltin dilaurate (0.05 mmol), and 20.0 mL of tetrahydrofuran (THF) were added and cooled to 10°C. Subsequently, 24.7 g of isocyanatopropyltriethoxysilane (KBE-9007N, 0.10 mol) was added at 10°C, and the mixture was allowed to react at room temperature for 24 hours. After that, the reaction solution was concentrated using a rotary evaporator. The concentrate was then vacuum dried to obtain S1 (yield 35.2 g), a transparent liquid. The obtained ST-1 １ The H NMR spectrum data was as follows: １ H NMR δ 0.628 (t, 2H), 1.22 (t, 9H) 1.64 (m, 2H), 3.21 (m, 2H), 3.82 (m, 6H), 5.01 (s, 1H), 5.09 (s, 2H), 7.25-7.37 (m, 5H).

[0084] <Organosilicon compounds other than (d1)> 3-MPS: γ-methacryloyloxypropyltrimethoxysilane KBM-13: methyltrimethoxysilane KBM-6803: N-(aminoethyl)-8-aminooctyltrimethoxysilane ST-2: 1-benzyl-3-(3-(triethoxysilyl)propyl)urea The structures, molecular weights, and reactivity of these organosilicon compounds are shown below.

[0085]

[0086] The above ST-2 was synthesized by the following method.

[0087] [Synthesis of ST-2] First, 10.7 g of benzylamine (0.10 mol) and 20.0 mL of tetrahydrofuran (THF) were added and cooled to 10°C. Subsequently, 24.7 g of isocyanatopropyltriethoxysilane (KBE-9007N, 0.10 mol) was added at 10°C, and the mixture was allowed to react at room temperature for 24 hours. After that, the reaction solution was concentrated using a rotary evaporator. Furthermore, the concentrate was vacuum dried to obtain S2 (yield 35.1 g), which was a yellowish-white solid. Note that the obtained ST-2 １ The H NMR spectrum data was as follows: １H NMR δ 0.610 (t, 2H), 1.19 (t, 9H) 1.58 (m, 2H), 3.13 (m, 2H), 3.80 (m, 6H), 4.33 (s, 2H), 4.83 (t, 1H), 5.03 (t, 1H), 7.23-7.32 (m, 5H).

[0088] (4) Other additives <Polymerization inhibitor> HQME: Hydroquinone monomethyl ether BHT: Dibutylhydroxytoluene <UV absorber> SS701: 2-(2-hydroxy-5-methylphenyl)-2H-benzotriazole <Fluorescent agent> LZ: Lumilux Blue LZ

[0089] 2. Inorganic Powders (B) (1) Preparation of Spherical Silica-Zirconia Inorganic Powders FN1 to FN3 Before Surface Treatment Spherical silica-zirconia inorganic powders FN1 to FN3 (before surface treatment), which were used as raw materials for the various surface-treated powders used in the Examples and Comparative Examples, and each having the average primary particle size and specific surface area shown below, were prepared according to the method described in JP-A-58-110414. FN1: Average primary particle size 342 nm, specific surface area 8.16 m ２ / g ・FN2: Average primary particle diameter 150 nm, specific surface area 23.0 m ２ / g ・FN3: Average primary particle diameter 1040 nm, specific surface area 4.10 m ２ / g.

[0090] The average primary particle size and specific surface area were measured by the following methods.

[0091] [Method for measuring average primary particle diameter] A powder was photographed using a scanning electron microscope (SEM) (Philips, "XL-30S"), and the number of all particles (30 or more) observed within a unit field of view of the photograph and the primary particle diameter (maximum diameter) of the total particle diameter were measured, and calculation was performed based on the obtained measured values.

[0092] [Method for measuring specific surface area] Measurement was performed using the BET method. That is, first, a measurement sample tube was weighed, 0.1 g of FN1 was placed in it, and the tube was vacuum-dried at 100°C for 30 minutes or more using a pretreatment device Bel-Vac (manufactured by Microtrac-Bell). After drying, the measurement sample tube containing the filler was weighed to determine the sample weight. The tube was then connected to the measurement section of a Bel-Sorp mini II pore size analyzer (manufactured by Microtrac-Bell) and the monolayer adsorption amount was determined using the BET method from the nitrogen desorption isotherm measured at the liquid nitrogen temperature. The monolayer adsorption amount was calculated as the product of the monolayer adsorption amount and the nitrogen adsorption occupied cross-sectional area.

[0093] (2) Preparation of Powders and Granules The spherical silica-zirconia inorganic powders FN1 to FN3 were surface-treated with various surface treatment agents to prepare inorganic powders F1 to F5 and CF1 to CF4 (powder particles obtained by various surface treatments using FN1), CF5 (powder particles obtained by surface treatment using FN2), and CF6 (powder particles obtained by surface treatment using FN3). Furthermore, organic-inorganic composite powder DF1 was prepared using the spherical silica-zirconia inorganic powder FN2. The manufacturing methods, analytical methods, and results of these surface-treated inorganic powders F1 to F8 and CF1 to CF6 and organic-inorganic composite powder DF1 are described below.

[0094] [Preparation of Inorganic Powder F1] First, 20 g of FN1 (raw material powder (b1)), 60 mL of dichloromethane, and 0.5 g of n-propylamine were placed in a 0.4 L zirconia pot, followed by the addition of 400 g of zirconia balls with a diameter of 5 mm, and the pot was then closed with a lid. The zirconia pot was rotated for 3 hours with a roller (shaft rotation speed: 450 rpm, pot rotation speed: 115 rpm) to obtain a dispersed slurry. Subsequently, 0.72 g of 3-MPS and 0.083 g of KBM-573 were simultaneously added to the dispersion slurry and stirred for 30 minutes with a roller (shaft rotation speed 450 rpm, pot rotation speed 115 rpm), after which 0.080 g of KBM-13 (10 mol% of the silane coupling agent) was added and stirred for 30 minutes with a roller (shaft rotation speed 450 rpm, pot rotation speed 115 rpm). The resulting surface-treated slurry was concentrated and dried in an evaporator to obtain a powder. The resulting powder was vacuum-dried at 80 ° C. for 15 hours to obtain inorganic powder F1. Note that KBM-573 corresponds to (d1), and 3-MPS and KBM-13 do not correspond to (d1), so the proportion of (d1) in the specific silane coupling agent (D) used for treatment (treatment amount) is 8.5 mol%. This ratio (treatment amount) corresponds to the amount of (d1) in the silane coupling agent (D) actually supported (present) on the surface of the untreated inorganic powder or particle (b1).

[0095] 0.01g of the obtained F1 was weighed out and placed in the measurement section of a thermogravimetric differential thermal analyzer Thermo Plus Evo TG8120 (manufactured by RIGAKU Corporation), after which 0.01g of aluminum oxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was placed as a reference. Next, the temperature was raised from 25 ° C. at a rate of 20 ° C. / min, and after heating to 500 ° C., it was held for 5 minutes. The weight loss rate measured by dividing the weight loss from the initial weight by the initial weight at this time was 1.37%. In addition, the surface treatment amount per unit area of ​​the silane coupling agent calculated based on this value: TQ (TQ because a specific silane coupling agent is used) Ｄ ) is 0.72 x 10 －５ (mol / m ２ ) was.

[0096] [Preparation of Inorganic Powders F2-F8 and CF1-CF4] Inorganic powders F2-F8 and CF1-CF4 were prepared and analyzed according to the above method, varying the type and amount of organosilicon compound used as the silane coupling agent. The compositions of the silane coupling agents and the results are shown in Table 1. The "mol %" in the table represents the percentage of the total number of moles of organosilicon compounds corresponding to (d1) relative to the total number of moles of all organosilicon compounds used as silane coupling agents. As can be seen from the table, F1-F8 correspond to inorganic powders (B1) surface-treated with specific silane coupling agent (D). In contrast, CF1 corresponds to inorganic powders (B2) that contain (d1) but have a low content and have an average primary particle size of 200-1000 nm, and are treated with a silane coupling agent that does not correspond to specific silane coupling agent (D). CF2 to CF4 correspond to inorganic powders and particles B2, which are treated with a silane coupling agent and do not contain (d1) and have an average primary particle size of 200 to 1000 nm.

[0097] [Preparation of inorganic powder CF5] FN2 having an average primary particle diameter of 150 nm was used as the raw powder instead of FN1, and inorganic powder CF5 (corresponding to B3) was surface-treated with a specific silane coupling agent (D) having the composition shown in Table 1 and analyzed.

[0098] [Preparation of inorganic powder CF6] CF6 (corresponding to B4) was prepared and analyzed in accordance with the above-mentioned method and in accordance with the composition of the silane coupling agent shown in Table 1, except that FN3 having an average primary particle diameter of 1040 nm was used instead of FN1 as the raw powder, and that the inorganic powder was surface-treated with a specific silane coupling agent (D) having the composition shown in Table 1.

[0099] [Preparation of Organic-Inorganic Composite Powder DF1] Organic-inorganic composite powder DF1 was prepared using the production method described in WO 2011 / 115007 or WO 2013 / 039169. Specifically, 100 g of inorganic powder FN2 and 0.4 g of sodium polyacrylate (manufactured by Polysciences Co., Ltd.) were first added to 200 g of water, and an aqueous dispersion of these was obtained using a circulation mill "SC Mill" (trade name; manufactured by Mitsui Mining Co., Ltd.). Meanwhile, 4 g (0.016 mol) of 3-MPS and 0.003 g of acetic acid were added to 80 g of water and stirred for 1 hour and 30 minutes to obtain a uniform solution with a pH of 4. This solution was added to the inorganic powder dispersion and mixed until uniform. Thereafter, the dispersion was lightly mixed and supplied onto a disk rotating at high speed, followed by granulation by spray drying. Spray drying was performed using a spray dryer equipped with a rotating disk and atomizing by centrifugal force (Spray Dry "TSR-2W", product name: manufactured by Sakamoto Giken Co., Ltd.). The disk rotation speed was 10,000 rpm, and the temperature of the drying atmosphere air was 200°C. The powder obtained by granulation via spray drying was then vacuum dried at 60°C for 18 hours to obtain 71 g of spherical inorganic agglomerated particles. Next, 10.0 g of the inorganic agglomerated particles were immersed in a polymerizable monomer solution (containing 35.6 parts by mass of polymerizable monomer per 100 parts by mass of organic solvent) prepared by mixing 1.78 g of UDMA as a polymerizable monomer, 0.005 g of 2,2'-azobis(2,4-dimethylvaleronitrile) as a polymerization initiator, and 5.0 g of ethanol as an organic solvent. The mixture was thoroughly stirred, and after confirming that it had become a slurry, it was allowed to stand for 1 hour. The mixture was transferred to a rotary evaporator. The mixture was dried for 1 hour under stirring conditions at a reduced pressure of 10 hectopascals and heating conditions of 40°C (using a hot water bath) to remove the organic solvent. After the organic solvent was removed, a powder with high fluidity was obtained. The obtained powder was heated for 1 hour under reduced pressure of 10 hectopascals and heating conditions of 100°C while stirring in a rotary evaporator, thereby polymerizing and curing the polymerizable monomer in the powder. This operation yielded 8.5 g of organic-inorganic composite powder DF1.

[0100]

[0101] 4. Examples and Comparative Examples Example 1 (1) Preparation of Curable Composition To 100 parts by mass of polymerizable monomers, which were 80 parts by mass of UDMA and 20 parts by mass of 3G, 0.2 parts by mass of CQ, 0.5 parts by mass of DMBE, 0.4 parts by mass of SS701, 0.05 parts by mass of HQME, 0.3 parts by mass of BHT, and 0.025 parts by mass of LZ were added and mixed to prepare a uniform matrix composition M1.

[0102] Next, 150 parts by mass of F1 per 100 parts by mass of M1 was weighed out into a mortar, and 100 parts by mass of the matrix composition was gradually added under red light, followed by thorough kneading in a dark place to obtain a uniform paste. This paste was then degassed under reduced pressure to remove air bubbles, yielding a curable composition (paste P1).

[0103] (2) Evaluation of the Hardenable Composition The dental hardenable composition (Paste P1) obtained was evaluated using a rheometer MCR302 (manufactured by Anton Paar) as follows. Specifically, 0.8 g of the hardenable composition (Paste P1) was placed on the sample stage of the rheometer and pressed against the sample with the measurement plate to a thickness of 1 mm. Excess paste was removed using a spatula to prevent excess paste from seeping onto the upper surface of the measurement plate. The temperature was then linearly changed from 20°C to 60°C over 5 minutes at a shear rate of 5 / s, and the change in viscosity over time (temperature dependence) was examined. The viscosity was measured at 20°C, 25°C, 37°C, and 42°C. The resulting viscosity changes are shown in Figure 1. The viscosities at each temperature were 159 Pa·s at 20°C, 83 Pa·s at 25°C, 29 Pa·s at 37°C, and 12 Pa·s at 42°C.

[0104] Examples 2 to 14 and Comparative Examples 1 to 14 Curable compositions (pastes P2 to 14 and CP1 to 14) were prepared in the same manner as in Example 1, except that the composition of the matrix composition and the type and amount of inorganic powder and granules to be blended were changed as shown in Table 2, and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 3. The "temperature dependency of viscosity" of paste CP1 obtained in Comparative Example 1 is also shown in Figure 1.

[0105]

[0106]

[0107] As shown in Table 3 and FIG. 1, pastes P1 to P14 obtained in Examples 1 to 14, which satisfy the conditions specified in the present invention, show a significant change in viscosity from 20 to 25°C to 37 to 42°C, and this viscosity change occurs under mild conditions, with the viscosity at 42°C being 5 to 30 Pa s.

[0108] In contrast, as shown in Comparative Examples 1 to 8, even if the paste is prepared using an inorganic powder (B1) surface-treated with a specific silane coupling agent (D), if the other conditions of the present invention are not satisfied, the effects of the present invention are not obtained. That is, as shown in Comparative Examples 1 to 3, when there is no aromatic ring-free urethane monomer (a1), the viscosity change when heated to 42 ° C. is small regardless of the type of organosilicon compound (d1), the viscosity at 42 ° C. exceeds 30 Pa s, and the value obtained by dividing the viscosity at 25 ° C. by the viscosity at 42 ° C. is less than 5.0. The same is true for paste CP4 (Comparative Example 4) in which the content of aromatic ring-free urethane monomer (a1) is less than 50% by mass, and paste CP5 (Comparative Example 5) in which the content of aromatic ring-containing monomer (a2) is 30% by mass or more. Furthermore, paste CP6 (Comparative Example 6), in which the amount of inorganic powder (B1) (per 100 parts by mass of (A)) is less than 100 parts by mass and 120 parts by mass, contains 50 parts by mass of untreated FN1 and has a base amount of FN1 of 150 parts by mass, but has low fluidity under any temperature condition, making it difficult to fill the paste into the cavity. Furthermore, paste CP7 (Comparative Example 7), in which the content of inorganic powder (B1) is less than 120 parts by mass and does not contain any inorganic powder other than (B1), has extremely high fluidity under any temperature condition and is unable to maintain the strength of the hardened body. Conversely, paste CP8 (Comparative Example 8), in which the content of inorganic powder (B1) is more than 300 parts by mass, has a high viscosity under any temperature condition, making it difficult to fill the cavity.

[0109] In addition, as shown in Comparative Examples 9 to 14, the effect of the present invention is not obtained even when inorganic powder and granules (B1) are not used. That is, paste CP9 (Comparative Example 9) using CF1, which contains a silane coupling agent containing (d1) but whose content is less than 0.5 mol%, showed a viscosity suitable for reproducing the occlusal surface shape at room temperature, but the viscosity change when heated to 42 ° C was small, and the viscosity at 42 ° C was more than 30 Pa · s, and the value obtained by dividing the viscosity at 25 ° C by the viscosity at 42 ° C was less than 5.0. In addition, similar results were obtained with paste CP10 (Comparative Example 10) obtained using inorganic powder and granules CF2 treated with a silane coupling agent not containing (d1). Furthermore, in pastes CP11 (Comparative Example 11) and CP12 (Comparative Example 12) using inorganic powders CF3 and CF4 that have been surface-treated with a silane coupling agent containing an organosilicon compound having >NH or an organosilicon compound having >NH and an aromatic ring, but not a compound falling under (d1), sufficient viscosity reduction is not achieved even when heated to 37 ° C to 42 ° C. Furthermore, paste CP13 (Comparative Example 13) using CF5, a powder obtained by surface-treating FN2 having an average primary particle size of less than 200 nm with a specific silane coupling agent (D), has low fluidity under any temperature conditions, making it difficult to fill the paste into cavities. On the other hand, paste CP14 (Comparative Example 14) using FN3 having an average primary particle size of more than 1000 nm has an excessively low viscosity.

Claims

1. A dental curable composition comprising a radically polymerizable monomer component (A), inorganic powder and particles (B), and a polymerization initiator (C), wherein the radically polymerizable monomer component (A) contains 50% by mass or more of a radically polymerizable monomer (a1) having a urethane group in the molecule and no aromatic ring, and contains no or less than 30% by mass of a radically polymerizable monomer (a2) having an aromatic ring in the molecule, the inorganic powder and particles (B) comprising inorganic powder and particles (B1) having an average primary particle diameter of 200 nm or more and 1000 nm or less as measured using a scanning electron microscope (SEM), the surface of which is surface-treated with a silane coupling agent (D), and the content of the inorganic powder and particles (B1) is 120 parts by mass or more and 300 parts by mass or less per 100 parts by mass of the radically polymerizable monomer component (A), the silane coupling agent (D) is an organosilicon compound containing 0.5 mol % to 100 mol % of a compound (d1) represented by the following general formula (1), and the inorganic powder / particle (B1) is dispersed in the radical polymerizable monomer component (A) so that the surface of the inorganic powder / particle (B1) comes into contact with the radical polymerizable monomer (a1). (In the formula, X is a hydroxyl group or an alkoxy group having from 1 to 4 carbon atoms, n is an integer of from 1 to 3, Z is a hydrogen atom, a methyl group, an ethyl group, or a vinyl group, and Y is a monovalent organic group having an aromatic ring, which does not contain an amino group and does not contain either an imino group or a hydroxyl group, or which contains either an imino group or a hydroxyl group.) 2. The specific surface area of ​​the inorganic powder (b1) measured by the BET method is 5 (m ２ / g) or more 15 (m ２ / g) or less, wherein the specific surface area is S, the weight loss (g) per 1 (g) of the inorganic powder / particle (B1) when the inorganic powder / particle (B1) is measured using a thermogravimetric differential thermal analyzer (TG-DTA) in a temperature range of 25 (°C) to 500 (°C) at a heating rate of 20 (°C / min) is R, and the average molecular weight of (D) defined as the sum of the values ​​obtained by dividing the product of the molecular weight and the content (mol%) of each organosilicon compound constituting the silane coupling agent (D) by 100 is M, then the following formula is obtained: TQ Ｄ = (R / M) / S = R / (M × S) where TQ is the surface treatment amount per unit area of ​​(D) in the inorganic powder or particle (B1) defined by Ｄ But 6.5 x 10 －６ (mol / m ２ ) or more than 2.0 x 10 －５ (mol / m ２ 2. The dental hardenable composition according to claim 1, wherein the viscosity of the dental hardenable composition is 1000 ppm or less.

3. Using a rheometer, the shear rate was 5 (s －１ 3. The dental curable composition according to claim 1, wherein, when viscosity measurements are performed while raising the temperature from 20 to 60°C at a temperature rise rate of 8°C / min, the dental curable composition has a viscosity at 20 to 25°C of 100 to 300 Pa s, a viscosity at 37 to 42°C of 10 to 30 Pa s, and a viscosity at 37 to 42°C of 10 to 30 Pa s, and a value obtained by dividing the viscosity at 25°C by the viscosity at 42°C of 5.0 to 20.

0.

4. A method for producing inorganic powder particles (B1), the surface of which is treated with a silane coupling agent (D) to obtain inorganic powder particles (B1), the surface of which has an average primary particle diameter of 200 nm or more and 1000 nm or less as measured using a scanning electron microscope (SEM); and a method for producing inorganic powder particles (B1), the method comprising: blending a radically polymerizable monomer component (A), inorganic powder particles (B) containing the inorganic powder particles (B1), and a polymerization initiator (C) in an amount of 120 parts by mass or more and 300 parts by mass or less of the inorganic powder particles (B1) per 100 parts by mass of the radically polymerizable monomer component (A), wherein the silane coupling agent (D) is an organosilicon compound containing 0.5 mol % or more and 100 mol % or less of a compound (d1) represented by the following general formula (1), the radical polymerizable monomer component (A) contains 50 mass % or more of a radical polymerizable monomer (a1) having a urethane group in the molecule and no aromatic ring, and contains no or less than 30 mass % of a radical polymerizable monomer (a2) having an aromatic ring in the molecule; and the inorganic powder / granule (B1) is dispersed in the radical polymerizable monomer component (A) so that its surface comes into contact with the radical polymerizable monomer (a1). (In the formula, X is a hydroxyl group or an alkoxy group having from 1 to 4 carbon atoms, n is an integer of from 1 to 3, Z is a hydrogen atom, a methyl group, an ethyl group, or a vinyl group, and Y is a monovalent organic group having an aromatic ring, which does not contain an amino group and does not contain either an imino group or a hydroxyl group, or which contains either an imino group or a hydroxyl group.)

Images