Dental curable composition having high mechanical strength

Abstract

The present invention provides a dental curable composition comprising (A) a polymerizable monomer, (B) an inorganic filler, and (C) a polymerization initiator, wherein the polymerizable monomer (A) comprises (a1) a polyfunctional (meth)acrylate monomer comprising urethane bonds, (a2) a polyfunctional (meth)acrylate monomer comprising hydroxyl groups, and (a3) a polyfunctional (meth)acrylate monomer comprising carboxyl groups, the ratio by weight of (a1):(a2)+(a3) ranges from 1:1 to 9:1, the number of hydroxyl groups is not more than 0.5 relative to the number of (meth)acryloyl groups in one molecule of the above-mentioned (a2), and the number of carboxyl groups is not more than 0.5 relative to the number of (meth)acryloyl groups in one molecule of the above-mentioned (a3).

Claims

1. A dental curable composition comprising (A) a polymerizable monomer, (B) an inorganic filler, and (C) a polymerization initiator, wherein the polymerizable monomer (A) comprises (a1) a polyfunctional (meth)acrylate monomer comprising urethane bonds, (a2) a polyfunctional (meth)acrylate monomer comprising hydroxyl groups, and (a3) a polyfunctional (meth)acrylate monomer comprising carboxyl groups, the ratio by weight of (a1):(a2)+(a3) ranges from 1:1 to 9:1, the number of hydroxyl groups is not more than 0.5 relative to the number of (meth)acryloyl groups in one molecule of (a2), and the number of carboxyl groups is not more than 0.5 relative to the number of (meth)acryloyl groups in one molecule of (a3), and the polyfunctional (meth)acrylate monomer comprising hydroxyl groups (a2) and the polyfunctional (meth)acrylate monomer comprising carboxyl groups (a3) comprise both of methacryloyl groups and acryloyl groups in one molecule.

2. The dental curable composition according to claim 1, wherein viscosities of both of the polyfunctional (meth)acrylate monomer comprising hydroxyl groups (a2) and the polyfunctional (meth)acrylate monomer comprising carboxyl groups (a3) are from 10 to 1,000 mPa.Math.s (25 C.).

Description

EXAMPLES

(1) Although Examples of the present invention are specifically described below, the present invention is not intended to be limited to these Examples. The test methods in Examples and Comparative Examples are described below.

(2) Abbreviations and properties of the polyfunctional (meth)acrylate monomers comprising urethane bonds (a1) used in preparations of the curable dental composition are shown as follows:

(3) UDMA: 1,6-Bis(methacrylethyloxycarbonylamino)2,2,4-trimethylhexane, bifunctional urethane monomer, Molecular weight: 470

(4) 9UA: Nonifunctional urethane acrylate oligomer, Molecular weight: 760

(5) Abbreviations and properties of the (meth)acrylate monomer comprising hydroxyl groups (a2) used in preparations of the curable dental composition are shown as follows:

(6) GDMA: Glycerin dimethacrylate, hydroxyl groups/(meth)acrylate groups=0.5, Viscosity: 40 mPa.Math.s (25 C.)

(7) TRPA: Pentafunctional dipentaerythritol pentaacrylate, hydroxyl groups/(meth)acrylate groups=0.2, Viscosity: 40 mPa.Math.s (25 C.)

(8) AHMA: 2-Hydroxy-3-acryloyloxy propyl methacrylate, hydroxyl groups/(meth)acrylate groups=0.5, Viscosity: 40 mPa.Math.s (25 C.)

(9) Abbreviations and properties of the (meth)acrylate monomers comprising carboxyl groups (a3) used in preparations of the curable dental composition are shown as follows:

(10) GDSU: Reactant of glycerin dimethacrylate and succinic anhydride, carboxyl groups/(meth)acrylate groups=0.5, Viscosity: 40 mPa.Math.s (25 C.)

(11) TRSU: Reactant of pentafunctional dipentaerythritol pentaacrylate and succinic anhydride, carboxyl groups/(meth)acrylate groups=0.2, Viscosity: 40 mPa.Math.s (25 C.)

(12) AHSU: Reactant of 2-hydroxy-3-acryloyloxy propyl methacrylate and succinic anhydride, carboxyl groups/(meth)acrylate groups=0.5, Viscosity: 40 mPa.Math.s (25 C.)

(13) Abbreviations of the other monomers used in preparations of the curable dental composition are shown as follows:

(14) Bis-GMA: 2,2-bis(4-(2-hydroxy-3-methacryloxypropoxy) phenyl)propane, hydroxyl groups/(meth)acrylate groups=1.0, Viscosity: about 0.1 millions mPa.Math.s (25 C.)

(15) TEGDMA: Triethylene glycol dimethacrylate, Viscosity: 9 mPa.Math.s (25 C.)

(16) HEMA: 2-Hydroxyethyl methacrylate, hydroxyl groups/(meth)acrylate groups=1.0, Viscosity: 6 mPa.Math.s (25 C.)

(17) MA: Methacrylic acid, carboxyl groups/(meth)acrylate groups=1.0, Viscosity: 1 mPa.Math.s (25 C.)

(18) Abbreviations of inorganic fillers used in preparations of the curable dental composition are shown as follows:

(19) SPF: Spherical shape of silica fillers (d.sub.50: 1 m)

(20) NSF: Amorphous shape of silica fillers (d.sub.50: 3 m)

(21) Abbreviations of polymerization initiator (C) used in preparations of the curable dental composition are shown as follows:

(22) CQ: Camphor quinone

(23) DMBE: Ethyl dimethylaminobenzoate

(24) BPO: Benzoyl peroxide

(25) (1) Measurements of Bending Strength

(26) (1-1) Preparations of Bending Strength Test Samples (Photopolymerization)

(27) Methods: After filling up a metallic mold made from stainless steel (2522 mm: rectangular parallelepiped type) with a curable dental composition to be subjected to the test, covergrasses are placed at both sides of the metallic mold and pressure-welded with a glass slab. Subsequently, a photopolymerization irradiator (Solidilite V: manufactured by SHOFU, Inc.) is used to cure the front surface and the back surface of the composition by light-irradiating them for 3 minutes each. After its cured material was removed from the metallic mold, the cured material was subjected to a thermal polymerization (110 C., 15 min) using a thermal polymerization device.

(28) (1-2) Preparations of Bending Strength Test Samples (Thermal Polymerization)

(29) Methods: After filling up a metallic mold made from stainless steel (2522 mm: rectangular parallelepiped type) with a curable dental composition to be subjected to the test, the composition was pressurized and heat-molded at a condition of press pressure on metallic mold: 3t, molding temperature: 100 C., and press time: 10 min.

(30) (1-3) Methods of Bending Test

(31) Methods: Measurement of bending strength in this test is performed with Instron Universal Testing Machine (Instron 5567: manufactured by Instron company) and at a distance between fulcrums of 20 mm and a crosshead speed of 1 mm/min.

(32) (2) Evaluation of Aged Deterioration

(33) (2-1) Initial Bending Strength

(34) Methods: After each of test samples is immersed into water (at 37 C. for 24 hours), its bending strength was measured. This was made an initial bending strength.

(35) (2-2) Bending Strength after Thermal Cycling

(36) Methods: After each of test samples is immersed into water (at 37 C. for 24 hours), each of test samples is subjected to a thermal cycle test (in water at 4 C. to 60 C., immersion during 1 minute each, 2,000 times), and subsequently its bending strengths was measured. This was made a bending strength after thermal cycling.

(37) (2-3) Bending Strength Maintenance Rate

(38) Methods: In order to evaluate durability by aged deterioration for each of the test samples, its strength maintenance rate was calculated according to the following formula:
Bending strength maintenance rate=(bending strength after thermal cycling)/(initial bending strength)100
(3) Measurement of Amount of Water Absorption
(3-1) Preparation of Test Samples for Amount of Water Absorption (photopolymerization)

(39) Methods: After filling up a metallic mold made from stainless steel (15 mm in diameter1 mm in thickness) with a curable dental composition to be subjected to the test, covergrasses are placed at both sides of the metallic mold and pressure-welded with a glass slab. Subsequently, the photopolymerization irradiator (Solidilite V: manufactured by SHOFU, Inc.) is used to cure the front surface and the back surface of the composition by light-irradiating them for 3 minutes each. After its cured material was removed from the metallic mold, the cured material was subjected to a thermal polymerization (110 C., 15 min) using a thermal polymerization device.

(40) (3-2) Preparation of Test Samples for Amount of Water Absorption (Thermal Polymerization)

(41) Methods: After filling up a metallic mold made from stainless steel (15 mm in diameter1 mm in thickness) with a curable dental composition to be subjected to the test, the composition was pressurized and heat-molded at a condition of press pressure on metallic mold: 3t, molding temperature: 100 C., and press time: 10 min.

(42) (3-3) Test Method of Amount of Water Absorption

(43) Test method of amount of water absorption was carried out according to JIS T6517 (dental hard resin). Each of test samples was preserved in a desiccator, and weighted in 0.1 mg unit. Until the test samples have a decreased mass of less than 0.1 mg within 24 hours, the test samples were continued to be dried and weighted by repeating these operations, and final masses of dried test samples were made m.sub.1. Then, after the test samples were preserved in water at 37 C. for 7 days, masses of the water-absorbed test samples were made m.sub.2. The amount of water absorption of each of the test samples was calculated according to the following formula:
Amount of water absorption=(mass m.sub.2 of water-absorbed test samplemass m.sub.1 of dried test sample)/volume of test sample
Preparation of Binder Resins (R-1 to R-16)

(44) Binder resins were prepared by mixing in the compositions as shown in Table 1.

(45) TABLE-US-00001 TABLE 1 Ingredients R-1 R-2 R-3 R-4 R-5 R-6 R-7 R-8 R-9 R-10 R-11 R-12 R-13 R-14 R-15 R-16 R-17 (a1) UDAM 50 80 89 75 87.5 80 80 80 80 40 95 80 80 80 70 80 Polyfunctional 9UA 80 (meth)acrylate monomer comprising urethane bonds (a2) GDMA 49 15 10 15 5 30 2 15 Polyfunctional TRPA 15 (meth)acrylate AHMA 15 15 15 15 monomer comprising hydroxyl groups (a3) GDSU 1 5 1 10 7.5 30 3 5 5 Polyfunctional M-405S 5 (meth)acrylate AHSU 5 5 5 5 monomer comprising carboxyl groups Others Bis-GMA 15 20 TEGDMA 30 HEMA 15 MA 5 (C) CQ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Polymerization DMBE 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 initiator BPO 0.3 0.3
Preparation of Inorganic Filler (B-1)

(46) SPF (100 parts by weight) was surface-treated with -methacryloxy propyltrimethoxy silane (10 parts by weight) to obtain an inorganic filler (B-1).

(47) Preparation of Inorganic Filler (B-2)

(48) NSF (100 parts by weight) was surface-treated with -methacryloxy propyltrimethoxy silane (3 parts by weight) to obtain an inorganic filler (B-2).

(49) Production methods of the dental curable compositions used in Examples and Comparative Examples are shown below.

Example 1

(50) Binder resin (R-1): 30 parts by weight, Inorganic filler (B-1): 80 parts by weight, and AEROSIL R-972 (hydrophobized ultrafine particles of silicon dioxide): 1 part by weight were kneaded with a double planetary mixer and vacuum-degassed to obtain a dental curable composition.

Example 2

(51) Binder resin (R-2): 30 parts by weight, Inorganic filler (B-1): 85 parts by weight, and AEROSIL R-972 (hydrophobized ultrafine particles of silicon dioxide): 1 part by weight were kneaded with a double planetary mixer and vacuum-degassed to obtain a dental curable composition.

Example 3

(52) Binder resin (R-3): 30 parts by weight, Inorganic filler (B-1): 70 parts by weight, and AEROSIL R-972 (hydrophobized ultrafine particles of silicon dioxide): 1 part by weight were kneaded with a double planetary mixer and vacuum-degassed to obtain a dental curable composition.

Example 4

(53) Binder resin (R-4): 30 parts by weight, Inorganic filler (B-1): 85 parts by weight, and AEROSIL R-972 (hydrophobized ultrafine particles of silicon dioxide): 1 part by weight were kneaded with a double planetary mixer and vacuum-degassed to obtain a dental curable composition.

Example 5

(54) Binder resin (R-5): 30 parts by weight, Inorganic filler (B-1): 90 parts by weight, and AEROSIL R-972 (hydrophobized ultrafine particles of silicon dioxide): 1 part by weight were kneaded with a double planetary mixer and vacuum-degassed to obtain a dental curable composition.

Example 6

(55) Binder resin (R-6): 30 parts by weight, Inorganic filler (B-2): 80 parts by weight, and AEROSIL R-972 (hydrophobized ultrafine particles of silicon dioxide): 1 part by weight were kneaded with a double planetary mixer and vacuum-degassed to obtain a dental curable composition.

Example 7

(56) Binder resin (R-7): 30 parts by weight, Inorganic filler (B-1): 80 parts by weight, and AEROSIL R-972 (hydrophobized ultrafine particles of silicon dioxide): 1 part by weight were kneaded with a double planetary mixer and vacuum-degassed to obtain a dental curable composition.

Example 8

(57) Binder resin (R-8): 30 parts by weight, Inorganic filler (B-2): 80 parts by weight, and AEROSIL R-972 (hydrophobized ultrafine particles of silicon dioxide): 1 part by weight were kneaded with a double planetary mixer and vacuum-degassed to obtain a dental curable composition.

Example 9

(58) Binder resin (R-9): 30 parts by weight, Inorganic filler (B-1): 80 parts by weight, and AEROSIL R-972 (hydrophobized ultrafine particles of silicon dioxide): 1 part by weight were kneaded with a double planetary mixer and vacuum-degassed to obtain a dental curable composition.

Example 10

(59) Binder resin (R-10): 30 parts by weight, Inorganic filler (B-2): 80 parts by weight, and AEROSIL R-972 (hydrophobized ultrafine particles of silicon dioxide): 1 part by weight were kneaded with a double planetary mixer and vacuum-degassed to obtain a dental curable composition.

Example 11

(60) Binder resin (R-2): 30 parts by weight, Inorganic filler (B-1): 60 parts by weight, and AEROSIL R-972 (hydrophobized ultrafine particles of silicon dioxide): 1 part by weight were kneaded with a double planetary mixer and vacuum-degassed to obtain a dental curable composition.

Example 12

(61) Binder resin (R-2): 30 parts by weight, Inorganic filler (B-1): 90 parts by weight, and AEROSIL R-972 (hydrophobized ultrafine particles of silicon dioxide): 1 part by weight were kneaded with a double planetary mixer and vacuum-degassed to obtain a dental curable composition.

Comparative Example 1

(62) Binder resin (R-11): 30 parts by weight, Inorganic filler (B-1): 80 parts by weight, and AEROSIL R-972 (hydrophobized ultrafine particles of silicon dioxide): 1 part by weight were kneaded with a double planetary mixer and vacuum-degassed to obtain a dental curable composition.

Comparative Example 2

(63) Binder resin (R-12): 30 parts by weight, Inorganic filler (B-1): 80 parts by weight, and AEROSIL R-972 (hydrophobized ultrafine particles of silicon dioxide): 1 part by weight were kneaded with a double planetary mixer and vacuum-degassed to obtain a dental curable composition.

Comparative Example 3

(64) Binder resin (R-13): 30 parts by weight, Inorganic filler (B-1): 80 parts by weight, and AEROSIL R-972 (hydrophobized ultrafine particles of silicon dioxide): 1 part by weight were kneaded with a double planetary mixer and vacuum-degassed to obtain a dental curable composition.

Comparative Example 4

(65) Binder resin (R-14): 30 parts by weight, Inorganic filler (B-1): 80 parts by weight, and AEROSIL R-972 (hydrophobized ultrafine particles of silicon dioxide): 1 part by weight were kneaded with a double planetary mixer and vacuum-degassed to obtain a dental curable composition.

Comparative Example 5

(66) Binder resin (R-15): 30 parts by weight, Inorganic filler (B-1): 80 parts by weight, and AEROSIL R-972 (hydrophobized ultrafine particles of silicon dioxide): 1 part by weight were kneaded with a double planetary mixer and vacuum-degassed to obtain a dental curable composition.

Comparative Example 6

(67) Binder resin (R-16): 30 parts by weight, Inorganic filler (B-1): 80 parts by weight, and AEROSIL R-972 (hydrophobized ultrafine particles of silicon dioxide): 1 part by weight were kneaded with a double planetary mixer and vacuum-degassed to obtain a dental curable composition.

(68) The physical property test results of the prepared dental curable compositions are shown in Tables 2 and 3.

(69) TABLE-US-00002 TABLE 2 Ex- Ex- Ex- Ex- Ex- Ex- Ex- Ex- Ex- Ex- Ex- Ex- ample ample ample ample ample ample ample ample ample ample ample ample 1 2 3 4 5 6 7 8 9 10 11 12 Binder Names R-1 R-2 R-3 R-4 R-5 R-6 R-7 R-8 R-9 R-10 R-2 R-2 resin (a1):(a2) + (a3) 1:1 4:1 89:11 3:1 7:1 4:1 4:1 4:1 4:1 4:1 4:1 4:1 Number of hydroxyl 0.5 0.5 0.5 0.5 0.5 0.2 0.5 0.5 0.5 0.5 0.5 0.5 groups/number of (meth)acryloyl groups Number of carboxyl 0.5 0.5 0.5 0.5 0.5 0.2 0.5 0.5 0.5 0.5 0.5 0.5 groups/number of (math)acryloyl groups Inorganic Names B-1 B-1 B-1 B-1 B-1 B-2 B-1 B-2 B-1 B-2 B-1 B-1 filler Bending Initial (MPa) 230 244 240 248 233 243 251 253 232 222 219 233 strength After thermal cycling 207 220 229 224 211 225 237 241 221 211 209 218 (MPa) Bending strength 90 90.2 95.4 90.3 90.6 92.6 94.4 95.3 95.3 95 95.4 93.6 maintenance rate (%) Amount Amount of water 30 29 29 30 29 30 27 28 29 30 27 30 of water absorption (g/mm.sup.3) absorption

(70) TABLE-US-00003 TABLE 3 Comparative Comparative Comparative Comparative Comparative Comparative Conparative Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Binder Names R-11 R-12 R-13 R-14 R-15 R-16 R-17 resin (a1):(a2) + (a3) 2:3 19:1 4:1 4:1 Number of hydroxyl 0.5 0.5 1.0 0.5 1.0 groups/number of (meth)acryloyl groups Number of carboxyl 0.5 0.5 0.5 1.0 groups/number of (meth) acryloyl groups Inorganic Names B-1 B-1 B-1 B-1 B-1 B-1 B-1 Bending strength Initial (MPa) 196 188 231 229 199 180 220 After thermal cycling 166 159 198 187 176 161 179 (MPa) Bending strength 84.7 84.6 85.7 81.7 88.4 89.4 81.4 maintenance rate (%) Amount Amount of water 34 33 35 34 35 29 35 of water absorption (g/mm.sup.3) absorption

Examples 1-12

(71) The dental curable compositions of Examples 1-12 had the ratio by weight of (a1):(a2)+(a3) ranged from 1:1 to 1:9, the number of hydroxyl groups/number of (meth)acryloyl groups in (a2) of not more than 0.5, and the number of carboxyl groups/number of (meth)acryloyl groups in (a3) of not more than 0.5.

(72) As a result, it was recognized that the dental curable compositions of Examples 1-12 had high bending strengths at the initial point and after thermal cyclings, and also had both of superior mechanical strengths and durabilities.

Comparative Examples 1 And 2

(73) The dental curable compositions of Comparative Examples 1 and 2 have used monomers having the number of hydroxyl groups/number of (meth)acryloyl groups in (a2) of not more than 0.5, and the number of carboxyl groups/number of (meth)acryloyl groups in (a3) of not more than 0.5. However, the ratios by weight of (a1):(a2)+(a3) do not range from 1:1 to 1:9. Therefore, although the compositions had high initial bending strengths, their bending strengths after the thermal cycling were poor and thereby it was recognized that the compositions had poor durability.

Comparative Example 3

(74) The dental curable composition of Comparative Example 3 had the ratio by weight of (a1):(a2)+(a3) ranged from 1:1 to 1:9. However, the number of hydroxyl groups/number of (meth)acryloyl groups in (a2) was 0.6 or more, and the initial bending strength was high, whereas the bending strength after the thermal cycling was low. Therefore, it was recognized that its durability was poor.

Comparative Example 4

(75) The dental curable composition of Comparative Example 4 had the ratio by weight of (a1):(a2)+(a3) ranged from 1:1 to 1:9. However, the number of carboxyl groups/number of (meth)acryloyl groups in (a3) was 0.6 or more, and the initial bending strength was high, whereas the bending strength after the thermal cycling was low. Therefore, it was recognized that its durability was poor.

Comparative Example 5

(76) The dental curable composition of Comparative Example 5 had the ratio by weight of (a1):(a2)+(a3) ranged from 1:1 to 1:9. However, both of the number of hydroxyl groups/number of (meth)acryloyl groups in (a2) and the number of carboxyl groups/number of (meth)acryloyl groups in (a3) were 0.6 or more, and the initial bending strength was high, whereas the bending strength after the thermal cycling was low. Therefore, it was recognized that its durability was poor.

Comparative Example 6

(77) The dental curable composition of Comparative Example 6 had a composition of common binder resins, and it was recognized that the bending strengths at the initial point and after the thermal cycling were low.