Dental curable composition and method of manufacturing same

Abstract

A dental curable composition includes a polymerizable monomer, inorganic particles (A), and inorganic particles (B), wherein the inorganic particles (A) have a volume-median particle size of more than or equal to 0.1 m and less than or equal to 0.9 m and are surface-treated with a compound expressed by a general formula (1), the inorganic particles (B) have an average primary particle size of more than or equal to 5 nm and less than or equal to 50 nm, where at least one of a group expressed by a general formula (A) and a group expressed by a general formula (B) is present at surfaces of the inorganic particles (B), and the ratio of the mass of the inorganic particles (B) to the total mass of the inorganic particles (A) and the inorganic particles (B) is more than or equal to 0.02 and less than or equal to 0.05.

Claims

1. A dental curable composition comprising: a polymerizable monomer, inorganic particles (A), and inorganic particles (B), wherein the inorganic particles (A) have a volume-median particle size of more than or equal to 0.1 m and less than or equal to 0.9 m and are surface-treated with a compound expressed by a general formula ##STR00007## (where R.sup.1 is a hydrogen atom or a methyl group, R.sup.2 is a hydrolyzable group, R.sup.3 is a hydrocarbon group having 1 to 6 carbon atoms, p is 2 or 3, and q is an integer greater than or equal to 8 and smaller than or equal to 13), wherein the inorganic particles (B) have an average primary particle size of more than or equal to 5 nm and less than or equal to 50 nm, where at least one of a group expressed by a general formula ##STR00008## (where R.sup.4 and R.sup.5 are independently a methyl group or an ethyl group) and a group expressed by a general formula ##STR00009## (where R.sup.6, R.sup.7, and R.sup.8 are independently a methyl group or an ethyl group) is present at surfaces of the inorganic particles (B), wherein a ratio of a mass of the inorganic particles (B) to a total mass of the inorganic particles (A) and the inorganic particles (B) is more than or equal to 0.02 and less than or equal to 0.05, wherein a ratio of a mass of the polymerizable monomer to the total mass of the inorganic particles (A) and the inorganic particles (B) is 0.25 to 0.5, and wherein an extrusion strength is less than or equal to 10 kgf.

2. The dental curable composition as claimed in claim 1, wherein the dental curable composition is a flowable composite resin.

3. A method of manufacturing a dental curable composition, the method comprising: mixing a polymerizable monomer, inorganic particles (A), and inorganic particles (B), wherein the inorganic particles (A) have a volume-median particle size of more than or equal to 0.1 m and less than or equal to 0.9 m and are surface-treated with a compound expressed by a general formula ##STR00010## (where R.sup.1 is a hydrogen atom or a methyl group, R.sup.2 is a hydrolyzable group, R.sup.3 is a hydrocarbon group having 1 to 6 carbon atoms, p is 2 or 3, and q is an integer greater than or equal to 8 and smaller than or equal to 13), wherein the inorganic particles (B) have an average primary particle size of more than or equal to 5 nm and less than or equal to 50 nm, where at least one of a group expressed by a general formula ##STR00011## (where R.sup.4 and R.sup.5 are independently a methyl group or an ethyl group) and a group expressed by a general formula ##STR00012## (where R.sup.6, R.sup.7, and R.sup.8 are independently a methyl group or an ethyl group) is present at surfaces of the inorganic particles (B), wherein a ratio of a mass of the inorganic particles (B) to a total mass of the inorganic particles (A) and the inorganic particles (B) is more than or equal to 0.02 and less than or equal to 0.05, wherein a ratio of a mass of the polymerizable monomer to the total mass of the inorganic particles (A) and the inorganic particles (B) is 0.25 to 0.5, and wherein an extrusion strength is less than or equal to 10 kgf.

4. The dental curable composition as claimed in claim 1, wherein the inorganic particles (A) are spherical.

Description

EXAMPLES

(1) The present invention is described in detail below with reference to examples and comparative examples, but is not limited to the examples. Part means part by mass.

(2) [Manufacture of Inorganic Particles (A-1)]

(3) Irregularly-shaped barium glass particles GM27884 NanoFine 180 (manufactured by Schott AG) having a volume-median particle size of 0.18 m were surface-treated with 8-methacryloyloxyoctyltrimethoxysilane to obtain inorganic particles (A-1) having a volume-median particle size of 0.18 m.

(4) [Manufacture of Inorganic Particles (A-2)]

(5) Inorganic particles (A-2) having a volume-median particle size of 0.4 m were obtained in the same manner as the inorganic particles (A-1) except for using barium glass particles G018-053 Ultra Fine 0.4 (manufactured by Schott AG) having a volume-median particle size of 0.40 m instead of irregularly-shaped barium glass particles GM27884 NanoFine 180 (manufactured by Schott AG) having a volume-median particle size of 0.18 m.

(6) [Manufacture of Inorganic Particles (A-3)]

(7) Inorganic particles (A-3) having a volume-median particle size of 0.7 m were obtained in the same manner as the inorganic particles (A-1) except for using barium glass particles G018-053 Ultra Fine 0.7 (manufactured by Schott AG) having a volume-median particle size of 0.70 m instead of irregularly-shaped barium glass particles GM27884 NanoFine 180 (manufactured by Schott AG) having a volume-median particle size of 0.18 m.

(8) [Manufacture of Inorganic Particles (A-4)]

(9) Inorganic particles (A-4) having a volume-median particle size of 0.18 m were obtained in the same manner as the inorganic particles (A-1) except for using 3-methacryloyloxypropyltrimethoxysilane instead of 8-methacryloyloxyoctyltrimethoxysilane.

(10) [Manufacture of Inorganic Particles (A-5)]

(11) Inorganic particles (A-5) having a volume-median particle size of 0.4 m were obtained in the same manner as the inorganic particles (A-2) except for using 3-methacryloyloxypropyltrimethoxysilane instead of 8-methacryloyloxyoctyltrimethoxysilane.

(12) [Manufacture of Inorganic Particles (A-6)]

(13) Inorganic particles (A-6) having a volume-median particle size of 0.7 m were obtained in the same manner as the inorganic particles (A-3) except for using 3-methacryloyloxypropyltrimethoxysilane instead of 8-methacryloyloxyoctyltrimethoxysilane.

(14) [Manufacture of Inorganic Particles (A-7)]

(15) Inorganic particles (A-7) having a volume-median particle size of 2.0 m were obtained in the same manner as the inorganic particles (A-1) except for using irregularly-shaped barium glass particles 8235 Ultra Fine 2.0 (manufactured by Schott AG) having a volume-median particle size of 2.0 m instead of irregularly-shaped barium glass particles GM27884 NanoFine 180 (manufactured by Schott AG) having a volume-median particle size of 0.18 m.

(16) Table 1 shows characteristics of the inorganic particles (A).

(17) TABLE-US-00001 TABLE 1 Volume- Median Particle Inorganic Size Particles [m] Surface Treatment Agent A-1 0.18 8-methacryloyloxyoctyltrimethoxysilane A-2 0.40 8-methacryloyloxyoctyltrimethoxysilane A-3 0.70 8-methacryloyloxyoctyltrimethoxysilane A-4 0.18 3-methacryloyloxypropyltrimethoxysilane A-5 0.40 3-methacryloyloxypropyltrimethoxysilane A-6 0.70 3-methacryloyloxypropyltrimethoxysilane A-7 2.0 8-methacryloyloxyoctyltrimethoxysilane
[Volume-Median Particle Size of Inorganic Particles (A)]

(18) 15 mg of the inorganic particles (A) were added to 20 mL of a 0.2 mass % sodium hexametaphosphate solution, and the inorganic particles (A) were dispersed for 30 minutes using an ultrasonic disperser to obtain a dispersion of the inorganic particles (A). Then, the volume-median particle size of the inorganic particles (A) was measured using a laser diffraction particle size distribution analyzer LA-950 (manufactured by HORIBA, Ltd).

(19) [Inorganic Particles (B-1)]

(20) Silica particles Aerosil R812 (manufactured by Nippon Aerosil Co., Ltd.), having an average primary particle size of 7 nm and surface-treated with hexamethyldisilazane, were used as inorganic particles (B-1).

(21) [Inorganic Particles (B-2)]

(22) Silica particles Aerosil R972 (manufactured by Nippon Aerosil Co., Ltd.), having an average primary particle size of 16 nm and surface-treated with dimethyldichlorosilane, were used as inorganic particles (B-2).

(23) [Inorganic Particles (B-3)]

(24) Silica particles Aerosil OX-50 (manufactured by Nippon Aerosil Co., Ltd.) having an average primary particle size of 40 nm were treated with 3-methacryloyloxypropyltrimethoxysilane to obtain inorganic particles (B-3) having an average primary particle size of 40 nm.

(25) Table 2 shows characteristics of the inorganic particles (B).

(26) TABLE-US-00002 TABLE 2 Average Primary Particle Inorganic Size Particles [nm] Surface Treatment Agent B-1 7 Hexamethyldisilazane B-2 16 Dimethyldichlorosilane B-3 40 3-methacryloyloxypropyltrimethoxysilane
[Average Primary Particle Size of Inorganic Particles (B)]

(27) Electron micrographs of 100 inorganic particles (B) were subjected to image analysis using image analysis software WinROOF (manufactured by MITANI Corporation), and thereafter, the average primary particle size of the inorganic particles (B) was calculated as a volume average particle size.

Example 1

(28) 30.4 parts of 2,2-bis[4-(2-methacryloyloxyethoxy)phenyl]propane (Bis-MEPP), 8.7 parts of [2,2,4-trimethylhexamethylene bis(2-carbamoyloxyethyl)]dimethacrylate (UDMA), and 4.3 parts of triethylene glycol di(meth)acrylate (TEGDMA) were mixed to obtain a polymerizable monomer.

(29) An appropriate amount of each of camphorquinone, ethyl N,N-dimethylaminobenzoate, trimethyldiphenylphosphine oxide, and dibutylhydroxytoluene (BHT) was added to the polymerizable monomer to obtain a polymerizable monomer composition.

(30) 98.0 parts of the inorganic particles (A-1) and 2.0 parts of the inorganic particles (B-1) were added to the polymerizable monomer composition, and after mixing and kneading for homogeneity, vacuum defoaming was performed to obtain a flowable composite resin in paste form.

Example 2

(31) A flowable composite resin in paste form was obtained in the same manner as in Example 1 except for changing the amounts of addition of the inorganic particles (A-1) and the inorganic particles (B-1) to 97.5 parts and 2.5 parts, respectively.

Example 3

(32) A flowable composite resin in paste form was obtained in the same manner as in Example 1 except for changing the amounts of addition of Bis-MEPP, UDMA, and TEGDMA to 27.4 parts, 7.8 parts, and 3.9 parts, respectively, and using the inorganic particles (A-2) instead of the inorganic particles (A-1).

Example 4

(33) A flowable composite resin in paste form was obtained in the same manner as in Example 3 except for changing the amounts of addition of the inorganic particles (A-2) and the inorganic particles (B-1) to 97.5 parts and 2.5 parts, respectively.

Example 5

(34) A flowable composite resin in paste form was obtained in the same manner as in Example 3 except for using the inorganic particles (A-3) instead of the inorganic particles (A-2).

Example 6

(35) A flowable composite resin in paste form was obtained in the same manner as in Example 5 except for changing the amounts of addition of the inorganic particles (A-3) and the inorganic particles (B-1) to 97.5 parts and 2.5 parts, respectively.

Example 7

(36) A flowable composite resin in paste form was obtained in the same manner as in Example 3 except for changing the amounts of addition of the inorganic particles (A-2) and the inorganic particles (B-1) to 97.0 parts and 3.0 parts, respectively.

Example 8

(37) A flowable composite resin in paste form was obtained in the same manner as in Example 3 except for changing the amounts of addition of the inorganic particles (A-2) and the inorganic particles (B-1) to 96.0 parts and 4.0 parts, respectively.

Example 9

(38) A flowable composite resin in paste form was obtained in the same manner as in Example 3 except for changing the amounts of addition of the inorganic particles (A-2) and the inorganic particles (B-1) to 95.0 parts and 5.0 parts, respectively.

Example 10

(39) A flowable composite resin in paste form was obtained in the same manner as in Example 1 except for changing the amounts of addition of the inorganic particles (A-1) and the inorganic particles (B-1) to 95.0 parts and 5.0 parts, respectively.

Example 11

(40) A flowable composite resin in paste form was obtained in the same manner as in Example 5 except for changing the amounts of addition of the inorganic particles (A-3) and the inorganic particles (B-1) to 95.0 parts and 5.0 parts, respectively.

Example 12

(41) A flowable composite resin in paste form was obtained in the same manner as in Example 3 except for using the inorganic particles (B-2) instead of the inorganic particles (B-1).

Example 13

(42) A flowable composite resin in paste form was obtained in the same manner as in Example 9 except for using the inorganic particles (B-2) instead of the inorganic particles (B-1).

Comparative Example 1

(43) A flowable composite resin in paste form was obtained in the same manner as in Example 2 except for using the inorganic particles (A-4) instead of the inorganic particles (A-1).

Comparative Example 2

(44) A flowable composite resin in paste form was obtained in the same manner as in Example 4 except for using the inorganic particles (A-5) instead of the inorganic particles (A-2).

Comparative Example 3

(45) A flowable composite resin in paste form was obtained in the same manner as in Example 6 except for using the inorganic particles (A-6) instead of the inorganic particles (A-3).

Comparative Example 4

(46) A flowable composite resin in paste form was obtained in the same manner as in Example 3 except for changing the amounts of addition of the inorganic particles (A-2) and the inorganic particles (B-1) to 94.0 parts and 6.0 parts, respectively.

Comparative Example 5

(47) A flowable composite resin in paste form was obtained in the same manner as in Example 3 except for using the inorganic particles (A-7) instead of the inorganic particles (A-2).

Comparative Example 6

(48) A flowable composite resin in paste form was obtained in the same manner as in Comparative Example 2 except for changing the amounts of addition of Bis-MEPP, UDMA, and TEGDMA to 34.8 parts, 9.9 parts, and 4.9 parts, respectively.

Comparative Example 7

(49) A flowable composite resin in paste form was obtained in the same manner as in Example 3 except for using the inorganic particles (B-3) instead of the inorganic particles (B-1).

Comparative Example 8

(50) A flowable composite resin in paste form was obtained in the same manner as in Comparative Example 7 except for changing the amounts of addition of the inorganic particles (A-2) and the inorganic particles (B-3) to 96.0 parts and 4.0 parts, respectively.

(51) Table 3 shows characteristics of the flowable composite resins of the examples and the comparative examples.

(52) TABLE-US-00003 TABLE 3 Inorganic Particles Amount Amount of of Addition Addition Extrusion of A of B Strength A B [part] [part] [kgf] Example 1 A-1 B-1 98.0 2.0 4 Example 2 A-1 B-1 97.5 2.5 5 Example 3 A-2 B-1 98.0 2.0 3 Example 4 A-2 B-1 97.5 2.5 3 Example 5 A-3 B-1 98.0 2.0 3 Example 6 A-3 B-1 97.5 2.5 3 Example 7 A-2 B-1 97.0 3.0 5 Example 8 A-2 B-1 96.0 4.0 6 Example 9 A-2 B-1 95.0 5.0 8 Example 10 A-1 B-1 95.0 5.0 8 Example 11 A-3 B-1 95.0 5.0 9 Example 12 A-2 B-2 98.0 2.0 8 Example 13 A-2 B-2 95.0 5.0 8 Comparative A-4 B-1 97.5 2.5 28 Example 1 Comparative A-5 B-1 97.5 2.5 24 Example 2 Comparative A-6 B-1 97.5 2.5 12 Example 3 Comparative A-2 B-1 94.0 6.0 15 Example 4 Comparative A-7 B-1 98.0 2.0 5 Example 5 Comparative A-5 B-1 97.5 2.5 7 Example 6 Comparative A-2 B-3 98.0 2.0 8 Example 7 Comparative A-2 B-3 96.0 4.0 8 Example 8
[Extrusion Strength]

(53) Extrusion strength was evaluated using a cylindrical polyolefin resin syringe (an MI filling container of 7.7 mm in inner diameter and 78.6 mm in length), a cylindrical plunger fitted into the syringe from the rear end side of the syringe, and a needle chip (20G) to be attached to the tip of the syringe. Here, the needle of the needle chip is 0.65 mm in inner diameter and 13 mm in length, and is bent 50 at a position 7.5 mm from the tip. Furthermore, the syringe and the plunger are formed of a member opaque to environmental light.

(54) First, after filling the syringe with 2.0 mL of a flowable composite resin, the needle chip was attached to the tip of the syringe, and the plunger was pushed to extrude the flowable composite resin from the tip of the needle chip. At this point, extrusion strength was measured at 25 C., using a universal testing machine AG-IS (manufactured by Shimadzu Corporation). Specifically, while vertically retaining the storage container, a crosshead to which a jig for compressive strength test was attached was lowered at 10 ram/min. to apply a load on and extrude the flowable composite resin, and a maximum load at the time was determined as extrusion strength. Extrusion strength of 10 kgf or less is determined as being acceptable.

(55) Then, the flexural strength, the abrasion resistance, the polishability, the consistency, and the formability and handleability of the flowable composite resins were evaluated.

(56) [Flexural Strength]

(57) After filling a stainless steel mold of 2 mm2 mm25 mm with a flowable composite resin, the flowable composite resin was brought into press contact with slide glasses on the upper side and the lower side. Next, the flowable composite resin was cured by irradiating the upper surface and the lower surface at nine points on each surface with visible light for 10 seconds per point, using a G-Light Prima-II (manufactured by GC Corporation). Then, after being extracted from the mold, the cured product was stored in distilled water at 37 C. for 24 hours to obtain a test piece. At this point, five test pieces were made. Next, the flexural strength of the five test pieces was measured using a universal testing machine AG-IS (manufactured by Shimadzu Corporation) with the support span being 20 mm and the crosshead speed being 1 mm/min, and thereafter, the average value was calculated to be determined as flexural strength. A flexural strength of 160 MPa or more is determined as being acceptable.

(58) [Abrasion Resistance]

(59) After filling a dedicated mold with a flowable composite resin, the flowable composite resin was brought into press contact with slide glasses on the upper side and the lower side. Next, the upper surface and the lower surface of the flowable composite resin were irradiated with visible light for 10 seconds using a G-Light Prima-II (manufactured by GC Corporation) to cure the flowable composite resin. Furthermore, after being extracted from the mold, the cured product was stored in distilled water at 37 C. for 24 hours to obtain a test piece. Each test piece was attached to a bite abrasion tester (manufactured by TOKYO GIKEN, INC.), and after polishing an unpolymerized layer with #1000 abrasive paper, the overall length of the test piece before testing was measured. A slurry obtained by mixing and kneading the equal amounts of glycerin and Acricone AC (manufactured by Mitsubishi Rayon Co., Ltd.) was laid on the bite abrasion tester, and a test assuming 100,000 vertical and lateral bites was conducted against a PMMA plate. After the test, the overall length of each test piece was measured, and the abrasion resistance was evaluated by determining the difference between before and after the test as the amount of wear. A wear of 10 m or less is determined as being acceptable.

(60) [Polishability]

(61) After filling a mold of 15 mm in diameter and 1.5 mm in thickness with a flowable composite resin, the flowable composite resin was brought into press contact with slide glasses on the upper side and the lower side. Next, the flowable composite resin was cured by irradiating the upper surface and the lower surface at nine points on each surface with visible light for 10 seconds per point, using a G-Light Prima-II (manufactured by GC Corporation). Furthermore, the cured product was extracted from the mold to obtain a test piece. Next, a smooth surface of the test piece was polished under a dry condition, using #600 abrasive paper. Furthermore, using MICROMOTOR LM-III (manufactured by GC Corporation), with water being injected, polishing was performed for 10 seconds at a rotational speed of approximately 10,000 rpm using PRE SHINE (manufactured by GC Corporation), and thereafter, polishing was performed for 10 seconds at a rotational speed of approximately 10,000 rpm using DIA SHINE (manufactured by GC Corporation). Furthermore, the glossiness of the polished surface was measured at a measurement angle of 60, using a glossmeter VG-2000 (manufactured by NIPPON DENSHOKU INDUSTRIES CO., LTD.), and its ratio to that of a mirror serving as 100 was determined as glossiness. A glossiness of 60% or more is determined as being acceptable.

(62) [Consistency]

(63) After filling the syringe with a flowable composite resin, the flowable composite resin was left stationary for 2 hours at 25 C. Next, in a constant temperature and humidity dark room at 25 C. and 50% RH, 0.5 mL of the flowable composite resin were left stationary in a mound shape at the center of an OHP sheet of 5 cm5 cm, and an OHP sheet of 5 cm5 cm and a weight of 120 g were placed thereon. Furthermore, after the long diameter and the short diameter of the flowable composite resin after passage of 60 seconds were measured through a glass plate, the average value of the long diameter and the short diameter was calculated to be determined as consistency. Here, the long diameter means the longest one of the diameters passing through the center, and the short diameter means one perpendicular to the long diameter among the diameters passing through the center. A consistency of 25 to 35 mm is determined as being acceptable.

(64) [Formability and Handleability]

(65) Using the above-described syringe, plunger, and needle chip, 0.03 g of a flowable composite resin were extruded onto white mixing paper. At this point, the formability and handleability were evaluated. The formability and handleability were determined based on the following criteria.

(66) 1: The viscosity of a flowable composite resin is appropriate to make it possible to easily build up and correct the shape of the flowable composite resin.

(67) 2: The viscosity of a flowable composite resin is somewhat high to make it difficult to correct the shape of the flowable composite resin, or the viscosity of a flowable composite resin is somewhat low to make it difficult to build up the flowable composite resin.
3: The viscosity of a flowable composite resin is high to make it impossible to correct the shape of the flowable composite resin, or the viscosity of a flowable composite resin is low to make it impossible to build up the flowable composite resin.

(68) Table 4 shows the evaluation results of the flexural strength, the abrasion resistance, the polishability, the consistency, and the formability and handleability of the flowable composite resins.

(69) TABLE-US-00004 TABLE 4 Abra- Form- sion ability Flexural Resis- Polish- Consis- & Strength tance ability tency Handle- [MPa] [m] [%] [mm] ability Example 1 167 2 72 30 1 Example 2 169 2 73 29 1 Example 3 185 4 67 32 1 Example 4 178 3 68 31 1 Example 5 181 9 62 32 1 Example 6 168 8 63 33 1 Example 7 165 3 67 31 1 Example 8 168 3 67 31 1 Example 9 164 3 69 30 1 Example 10 163 7 61 30 1 Example 11 163 2 73 26 1 Example 12 172 3 68 30 1 Example 13 169 5 69 29 1 Comparative 163 3 74 18 3 Example 1 Comparative 168 5 65 20 3 Example 2 Comparative 173 10 62 32 2 Example 3 Comparative 164 3 67 24 3 Example 4 Comparative 158 51 32 34 2 Example 5 Comparative 154 6 63 27 1 Example 6 Comparative 153 5 63 28 1 Example 7 Comparative 156 5 64 29 1 Example 8

(70) Table 4 shows that the flowable composite resins of Examples 1 through 13 have good flexural strength, abrasion resistance, extrusion strength, polishability, consistency, and formability and handleability.

(71) In contrast, the flowable composite resins of Comparative Examples 1 through 3 and 6 contain the inorganic particles (A-4), (A-5) or (A-6) that are surface-treated with 3-methacryloyloxypropyltrimethoxysilane, and therefore cannot achieve both flexural strength and formability and handleability.

(72) The formability and handleability of the flowable composite resin of Comparative Example 4 are degraded because the ratio of the mass of the inorganic particles (B-1) to the total mass of the inorganic particles (A-2) and the inorganic particles (B-1) is 0.06.

(73) The flexural strength, the abrasion resistance, the polishability, and the formability and handleability of the flowable composite resin of Comparative Example 5 are degraded because of the inclusion of the inorganic particles (A-7) having a volume-median particle size of 2.0 m.

(74) The flexural strength of the flowable composite resins of Comparative Examples 7 and 8 is reduced because of the inclusion of the inorganic particles (B-2) that are surface-treated with 3-methacryloyloxypropyltrimethoxysilane.

(75) The present international application is based upon and claims the benefit of priority of Japanese Patent Application No. 2015-058647, filed on Mar. 20, 2015, the entire contents of which are hereby incorporated herein by reference.