DENTAL CURABLE COMPOSITION

Abstract

The present invention provides a dental curable composition used for dental filling restorative materials, dental crown prosthesis materials such as inlays, crowns, and bridges, materials for constructing anchor teeth, block materials for dental CAD/CAM, etc. More specifically, the present invention provides a dental curable composition comprising a curable resin (A), a porous inorganic filler (B), and a polymerization initiator (C), wherein the porous inorganic filler (B) comprises a silicon dioxide, and an oxide comprising at least one kind of the other metallic elements, and a ratio (I.sub.1/I.sub.2) of a maximum absorbance (I.sub.1) of 3730 to 3750 cm.sup.1 to a maximum absorbance (I.sub.2) of 3000 to 3600 cm.sup.1 in infrared absorption spectrum of the porous inorganic filler (B), is not less than 2 and not more than 3.

Claims

1. A dental curable composition comprising a curable resin (A), a porous inorganic filler (B), and a polymerization initiator (C), wherein the porous inorganic filler (B) comprises a silicon dioxide and an oxide comprising at least one kind of the other metallic elements, and a ratio (I.sub.1/I.sub.2) of a maximum absorbance (I.sub.1) of 3730 to 3750 cm.sup.1 to a maximum absorbance (I.sub.2) of 3000 to 3600 cm.sup.-2 in infrared absorption spectrum of the porous inorganic filler (B), is not less than 1 and not more than 3.

2. The dental curable composition according to claim 1 wherein the at least one kind of the other metallic elements of said porous inorganic filler (B) are oxides containing at least zirconium element.

Description

EXAMPLES

[0061] 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 as follows:

(1) Composition Analysis of Porous Inorganic Filler (B)

Purposes: Composition Analysis Measurement of the Porous Inorganic Filler (B)

[0062] Methods: The composition analysis of the porous inorganic filler (B) was measured with a fluorescent x -ray equipment. The combination ratio of the various metallic elements in the porous inorganic filler (B) was calculated with oxide conversion.

(2) Shape Measurement of Porous Inorganic Filler (B)

Purposes: Shape Measurement of the Porous Inorganic Filler (B)

[0063] Methods: The shape of the porous inorganic filler (B) was confirmed from its photography image of a scanning election microscope (hereinafter referred to as SEM). A mean particle size, the coefficient of variation of particle size and its circularity are obtained by processing the photography image of the above-mentioned SEM with the image-analysis equipment. The number of samples processed by their images is not less than 100. In addition, the circularity defined herein is determined by image-processing the photography image in SEM. Namely, by defining the area of the particles obtained with the image processing as S and the circumference length of particles as L,

Circularity=(4S)/(L2)

[0064] Moreover, circle equivalent diameter=(4S/)1/2 were used as the particle size. The shape of the porous inorganic filler (B) having a circularity of not less than 0.8 was defined as a spherical shape, whereas the shape of the porous inorganic filler (B) having a circularity of less than 0.3 was defined as an amorphous shape.

(3) Infrared Absorption Spectrum Measurement

Purposes: Measurement of the Infrared Absorption Spectrum by a Diffuse Reflection Method

[0065] Methods: The infrared absorption spectrum was measured with the diffuse reflection method of the infrared absorption spectrometer (JASCO FT-IR-6300, manufactured by JASCO Corp.) (measuring range: 400 to 8000 cm.sup.1 under nitrogen atmosphere). The maximum absorbance (I.sub.1) of 3730 to 3750 cm.sup.1 and the maximum absorbance (I.sub.2) of the peak pertaining to 3000 to 3600 cm.sup.1 were calculated from the obtained spectrum.

(4) Contrast Ratio Measurement

Purposes: Evaluation of Contrast Ratio (Transparency) in a Cured Body of the Dental Composition.

[0066] Methods: After filling up a metallic mold made from stainless steel (15 mm in diameter1 mm in thickness) with a composition to be subjected to the test, covergrasses are placed at both sides of the metallic mold and pressure-welded with the metallic mold. In the measurement after curing, the photopolymerization irradiator (Solidilite: 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. A test sample is color-measured with a spectrum chromatometer (manufactured by Konica Minolta Co., Ltd.). Y value upon color-measuring when a white board is placed under the cured body is defined as Y.sub.W, and Y value upon color-measuring when a black board is placed under a cured body is defined as Y.sub.B. The transparency of the cured body was evaluated by assuming C value=Y.sub.B/Y.sub.W as a contrast ratio. The material is more transparent when C value approaches 0, and the material is more opaque when C value approaches 1. The contrast ratio is preferably 0.50 or less to reproduce the color tone of natural teeth.

(5) Bending Strength Test

Purposes: Evaluation of Bending Strength For Cured Materials

[0067] Methods: After filling up a metallic mold made from stainless steel (2522 mm: rectangular parallelepiped type) with a 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: 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. A cured material was removed from the metallic mold after curing, and a cured material immersed into water at 37 C. for 24 hours was used as the test sample (first stage). Further, in order to evaluate durability by aged deterioration, the above-mentioned test sample is subjected to a thermal cycle test (in water at 4 C. to 60 C., immersion during 1 minute each, 2000 times), and subsequently a measurement of bending strength (after thermal cycling) was performed. 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. The bending strength measurements were performed at the initial and after the thermal cycling to calculate a strength maintenance rate under a durability to aged deterioration according to the following formula:

Bending strength maintenance rate=(initial bending strength)/(bending strength after thermal cycling)100

(Preparation of Binder Resin)

[0068] Seventy parts by weight of a di (methacryloxyethyl) trimethylhexamethylene diurethane (UDMA), 30 parts by weight of triethyleneglycol dimethacrylate (3G), 0.3 parts by weight of camphor quinone, and 2 parts by weight of dimethylaroino ethylmethacrylate were mixed to produce a binder resin (A-1).

[0069] Seventy parts by weight of 2,2-bis(4-(3-metacryloyloxy-2-hydroxypropoxy) phenyl)propane (Bis-GMA), 30 parts by weight of triethyleneglycol dimethacrylate (3G), 0.3 parts by weight of camphor quinone, and 2 parts by weight of dimethyiamino ethylmethacrylate were mixed to produce a binder resin (A-2).

(Production Method of Inorganic Fillers (Classified Dry Products and Pulverized Products))

Production Method 1 (ZrO.SUB.2.: 18% by Weight)

[0070] To 1,867 g of a silicon dioxide sol in which a silicon dioxide sol (manufactured by JGC Catalysts and Chemicals Ltd., CATALOID S-20L, a mean particle size of 17 nm, 10% by weight of SiO.sub.2) was diluted to a concentration of 3% by weight as SiO.sub.2, 35 g of an aqueous KaOH solution at a concentration of 3% by weight was added to adjust pH at 9.6. Moreover, after preparing an aqueous sodium silicate solution (diluted water glass) at a concentration of 3.0% by weight as SiO.sub.2. by diluting water glass (No. 3 sodium silicate manufactured by AGC Si-Tech Co., Ltd.), its dealkalization was performed by using a strongly acidic cation exchange resin (H type of SK1B, manufactured by Mitsubishi Chemical, Inc.) to prepare 525 g of an acidic silicic acid solution at a concentration of 3.0% by weight as SiO.sub.2. This acidic silicic acid solution was mixed with the diluted silicon dioxide sol adjusted of pH, 41 g of an aqueous NaCH solution at a concentration of 3% by weight was added to prepare a mixed slurry of the acidic silicic acid solution and the silicon dioxide sol, adjusted to pH of 9.6. To this, 394 g of an aqueous zirconium ammonium carbonate solution diluted with water was added as a component other than the silicon dioxide such that a zirconium ammonium carbonate (manufactured by Daiichi Kigenso Kagaku Xogyo Co., Ltd.: Zircosol AC-7, ZrO.sub.2: 13% by weight) becomes 4% by weight as ZrO.sub.2, and then agitated for 15 min to prepare a mixed slurry. Subsequently, spray drying was performed with a disk type spray dryer under a condition of an entrance temperature of 30 C., and an outlet temperature of 50 C. for hot air, and a supply rate of 200 g/min of the mixed slurry. The resultant powder was dried at 110 C. for 15 hours, and subsequently heat-treated at 650 C. for 3 hours (primary heat-treatment) to prepare a primary heat-treated product. Then, wet sedimentation was performed by using an absolute ethanol (traceable 99 primary, manufactured by Japan Alcohol Co., Ltd.) and dried at 110 C. for 5 hours to prepare a classified dry product (1).

[0071] Particle size was measured with a laser diffraction dispersion type particle size distribution measuring equipment (SALD-200VER manufactured by Shimadzu Corp.), and their pore volume and specific surface area were measured by using K2 gas adsorption method by BELSORP-mini II manufactured by BEL Japan, Inc. The resultant classified dry product (1) had particle size: 2.9 m, specific surface area: 170 m.sup.2/g and pore volume: 0.22 cm.sup.3/g. In addition, the specific surface area was calculated by a BET method.

Production, Method 2 (ZrO.SUB.2.: 14% by Weight)

[0072] To 1,867 g of a silicon dioxide sol in which diluted the silicon dioxide sol (manufactured by JGC Catalysts and Chemicals Ltd.: CATALOID S-20L, a mean particle size of 17 nm, 10% by weight of SiO.sub.2) was diluted to a concentration of 3% by weight as SiO.sub.2, 35 g of an aqueous NaOH solution at a concentration of 3% by weight was added to adjust pH at 9.6. Moreover, after preparing an aqueous sodium silicate solution (diluted water glass) at a concentration of 3.0% by weight as SiO.sub.2 by diluting water glass (No. 3 sodium silicate manufactured by AGC Si-Tech Co., Ltd.), its dealkalization was performed by using a strongly acidic cation exchange resin (H type of SK1B, manufactured by Mitsubishi Chemical, Inc.) to prepare 1,001 g of an acidic silicic acid solution at a concentration of 3.0% by weight as SiO.sub.2. This acidic silicic acid solution was mixed with the diluted silicon dioxide sol adjusted of pH, 56 g of an aqueous NaOH solution at a concentration of 3% by weight was added to prepare a mixed slurry of the acidic silicic acid solution and the silicon dioxide sol, adjusted to pH of 9.6. To this, 350 g of an aqueous zirconium ammonium carbonate solution diluted with water was added as a component other than the silicon dioxide such that a zirconium ammonium carbonate (manufactured by Daiichi Kigenso Kagaku Xogyo Co., Ltd.: Zircosol AC-7, ZrO.sub.2: 13% by weight) becomes 4% by weight as ZrO.sub.2, and then agitated for 15 min to prepare a mixed slurry. Subsequently, the same method as that of Production method 1 was performed to prepare a classified dry product (2). The resultant classified dry product (2) had particle size: 2.9 m, specific surface area: 151 m.sup.2/g and pore volume: 0.18 cm.sup.3/g.

Production Method 3 (ZrO.sub.2: 5% by weight)

[0073] To 1,867 g of a silicon dioxide sol in which a silicon dioxide sol (manufactured by JGC Catalysts and Chemicals Ltd.: CATALOID S-20L, a mean particle size of 17 nm, 10% by weight of SiO.sub.2) was diluted to a concentration of 3% by weight as SiO.sub.2, 35 g of an aqueous NaOH solution at a concentration of 3% by weight was added to adjust pH at 9.6. Moreover, after preparing an aqueous sodium silicate solution (diluted water glass) at a concentration of 3.0% by weight as SiO.sub.2 by diluting water glass (No. 3 sodium silicate manufactured by AGC Si-Tech Co., Ltd.), its dealkalization was performed by using a strongly acidic cation exchange resin (H type of SK1B, manufactured by Mitsubishi Chemical, Inc.) to prepare 862 g of an acidic silicic acid solution at a concentration of 3.0% by weight as SiO.sub.2. This acidic silicic acid solution was mixed with the diluted silicon dioxide sol adjusted of pH, 51 g of an aqueous NaOH. solution at a concentration of 3% by weight was added to prepare a mixed slurry of the acidic silicic acid solution and the silicon dioxide sol, adjusted to pH of 9.6. To this, 108 g of an aqueous zirconium ammonium carbonate solution diluted with water was added as a component other than the silicon dioxide such that a zirconium ammonium carbonate (manufactured by Daiichi Kigenso Kagaku Xogyo Co., Ltd.: Zircosol AC-7, ZrO.sub.2: 13% by weight) becomes 4% by weight as ZrO.sub.2, and then agitated for 15 min to prepare a mixed slurry. Subsequently, the same method as that of Production method 1 was performed to prepare a classified dry product (3). The resultant classified dry product (3) had particle size: 2.9 m, specific surface area: 175 m.sup.2/g and pore volume: 0.21 cm.sup.3/g.

Production Method 4 (ZrO.SUB.2.: 35% by Weight)

[0074] To 1,867 g of a silicon dioxide sol in which a silicon dioxide sol (manufactured by JGC Catalysts and Chemicals Ltd.: CATALOID S-20L, a mean particle size of 17 nm, 10% by weight of SiO.sub.2) was diluted to a concentration of 3% by weight as SiO.sub.2, 35 g of an aqueous NaOH solution at a concentration of 3% by weight was added to adjust pH at 9.6. Moreover, after preparing an aqueous sodium silicate solution (diluted water glass) at a concentration of 3.0% by weight as SiO.sub.2 by diluting water glass (No. 3 sodium silicate manufactured by AGC Si-Tech Co., Ltd.), its dealkalization was performed by using a strongly acidic cation exchange resin (H type of SK1B, manufactured by Mitsubishi Chemical, Inc.) to prepare 340 g of an acidic silicic acid solution at a concentration of 3.0% by weight as SiO.sub.2. This acidic silicic acid solution was mixed with the diluted silicon dioxide sol adjusted of pH, 35 g of an aqueous NaOH solution at a concentration of 3% by weight was added to prepare a mixed slurry of the acidic silicic acid solution and the silicon dioxide sol, adjusted to pH of 9.6. To this, 889 g of an aqueous zirconium ammonium carbonate solution diluted with water was added as a component other than the silicon dioxide such that a zirconium ammonium carbonate (manufactured by Daiichi Kigenso Kagaku Xogyo Co., Ltd.: Zircosol AC-7, ZrO.sub.2: 13% by weight) becomes 4% by weight as ZrO.sub.2, and then agitated for 15 min to prepare a mixed slurry. Subsequently, the same method as that of Production method 1 was performed to prepare a classified dry product (4).

[0075] The resultant classified dry product (4) had particle size: 2.9 m, specific surface area: 149 m.sup.2/g and pore volume: 0.17 cm.sup.3/g.

Production Method 5 (ZrO.sub.2: 0.5% by weight)

[0076] To 1,867 g of a silicon dioxide sol in which a silicon dioxide sol (manufactured by JGC Catalysts and Chemicals Ltd,: CATALOID S-20L, a mean particle size of 17 nm, 10% by weight of SiO.sub.2) was diluted to a concentration of 3% by weight as SiO.sub.2, 35 g of an aqueous NaOH solution at a concentration of 3% by weight was added to adjust pH at 9.6. Moreover, after preparing an aqueous sodium silicate solution (diluted water glass) at a concentration of 3.0% by weight as SiO.sub.2 by diluting water glass (No. 3 sodium silicate manufactured by AGC Si-Tech Co., Ltd.), its dealkalization was performed by using a strongly acidic cation exchange resin (H type of SK1B, manufactured by Mitsubishi Chemical, Inc.) to prepare 1,254 g of an acidic silicic acid solution at a concentration of 3.0%. by weight as SiO.sub.2. This acidic silicic acid solution was mixed with the diluted silicon dioxide sol adjusted of pH, 87 g of an aqueous NaOH solution at a concentration of 3% by weight was added to prepare a mixed slurry of the acidic silicic acid solution and the silicon dioxide sol, adjusted to pH of 9.6. To this, 11 g of an aqueous zirconium ammonium carbonate solution diluted with water was added as a component other than the silicon dioxide such that a zirconium ammonium carbonate (manufactured by Daiichi Kigenso Kagaku Xogyo Co., Ltd.: Zircosol AC-7, ZrO.sub.2: 13% by weight) becomes 4% by weight as ZrO.sub.2, and then agitated for 15 min to prepare a mixed slurry. Subsequently, the same method as that of Production method 1 was performed to prepare a classified dry product (5).

[0077] The resultant classified dry product (5) had particle size: 2.9 m, specific surface area: 161 m.sup.2/g and pore volume: 0.19 cm.sup.3/g.

Production Method 6 (TiO.sub.2: 6% by weight)

[0078] To 1,867 g of a silicon dioxide sol in which a silicon dioxide sol (manufactured by JGC Catalysts and Chemicals Ltd.: CATALOID S-20L, a mean particle size of 17 nm, 10% by weight of SiO.sub.2, was diluted to a concentration of 3% by weight as SiO.sub.2, 35 g of an aqueous NaOH solution at a concentration of 3% by weight was added to adjust pH at 9.6. Moreover, after preparing an aqueous sodium silicate solution (diluted water glass) at a concentration of 3.0% by weight as SiO.sub.2 by diluting water glass (No. 3 sodium silicate manufactured by AGO Si-Tech Co., Ltd.), its dealkalization was performed by using a strongly acidic cation exchange resin (H type of SK1B, manufactured by Mitsubishi Chemical, Inc.) to prepare 873 g of an acidic silicic acid solution at a concentration of 3.0% by weight as SiO.sub.2. This acidic silicic acid solution was mixed with the diluted silicon dioxide sol adjusted of pH, 52 g of an aqueous NaOH solution at a concentration of 3% by weight was added to prepare a mixed slurry of the acidic silicic acid solution and the silicon dioxide sol, adjusted to pH of 9.6. To this, 132 g of an aqueous titanyl sulfate solution diluted with water was added as a component other than the silicon dioxide such that a titanyl sulfate dihydrate (manufactured by TAYCA Corp.) becomes 4% by weight as TiO.sub.2, and then agitated for 15 min to prepare a mixed slurry. Subsequently, the same method as that of Production method 1 was performed to prepare a classified dry product (6).

[0079] The resultant classified dry product (6) had particle size: 2.9 m, specific surface area: 173 m.sup.2/g and pore volume: 0.21 cm.sup.3/g.

Production Method 7 (TiO.sub.2: 3% by weight)

[0080] To 1,867 g of a silicon dioxide sol in which a silicon dioxide sol (manufactured by JGC Catalysts and Chemicals Ltd.; CATALOID S-20L, a mean particle size of 17 nm, 10% by weight of SiO.sub.2) was diluted to a concentration of 3% by weight as SiO.sub.2, 35 g of an aqueous NaOH solution at a concentration of 3% by weight was added to adjust pH at 9.6. Moreover, after preparing an aqueous sodium silicate solution (diluted water glass) at a concentration of 3.0% by weight as SiO.sub.2 by diluting water glass (No. 3 sodium silicate manufactured by AGC Si-Tech Co., Ltd.), its dealkalization was performed by using a strongly acidic cation exchange resin (H type of SK1B, manufactured by Mitsubishi Chemical, Inc.) to prepare 833 g of an acidic silicic acid solution at a concentration of 3.0% by weight as SiO.sub.2 . This acidic silicic acid solution was mixed with the diluted silicon dioxide sol adjusted of pH, 50 g of an aqueous NaOH solution at a concentration of 3% by weight was added to prepare a mixed slurry of the acidic silicic acid solution and the silicon dioxide sol, adjusted to pH of 9.6. To this, 62 g of an aqueous titanyl sulfate solution diluted with water was added as a component other than the silicon dioxide such that titanyl sulfate dihydrate (manufactured by TAYCA Corp.) becomes 4% by weight as TiO.sub.2, and then agitated for 15 min to prepare a mixed slurry. Subsequently, the same method as that of Production method 1 was performed to prepare a classified dry product (7).

[0081] The resultant classified dry product (7) had particle size: 2.9 m, specific surface area: 180 m.sup.2/g and pore volume: 0.22 cm.sup.3/g.

Production Method 8 (BaO: 12% by weight)

[0082] To 1,867 g of a silicon dioxide sol in which a silicon dioxide sol (manufactured by JSC Catalysts and Chemicals Ltd.: CATALOID S-20L, a mean particle size of 17 nm, 10% by weight of SiO.sub.2) was diluted to a concentration of 3% by weight as SiO.sub.2, 35 g of an aqueous NaOH solution at a concentration of 3% by weight was added to adjust pH at 9,6. Moreover, after preparing an aqueous sodium silicate solution (diluted water glass) at a concentration of 3.0% by weight as SiO.sub.2 by diluting water glass (No. 3 sodium silicate manufactured by AGC Si-Tech Co., Ltd.), its dealkalization was performed by using a strongly acidic cation exchange resin (H type of SK1B, manufactured by Mitsubishi Chemical, Inc.) to prepare 965 g of an acidic silicic acid solution at a concentration of 3.0% by weight as SiO.sub.2. This acidic silicic acid solution was mixed with the diluted silicon dioxide sol adjusted of pH, 55 g of an aqueous NaOH solution at a concentration of 3% by weight was added to prepare a mixed slurry of the acidic silicic acid solution and the silicon dioxide sol, adjusted to pH of 9.6. To this, 287 g of an aqueous barium nitrate solution diluted with water was added as a component other than the silicon dioxide such that barium nitrate (manufactured by Wako Pure Chemical Industries, Ltd.) becomes 4% by weight as BaO, and then agitated for 15 min to prepare a mixed slurry. Subsequently, the same method as that of Production method 1 was performed to prepare a classified dry product (8).

[0083] The resultant classified dry product (8) had particle size: 2.9 m, specific surface area: 157 m.sup.2/g and pore volume: 0.18 cm.sup.3/g.

Production Method 9 (BaO: 7% by weight)

[0084] To 1,867 g of a silicon dioxide sol in which a silicon dioxide sol (manufactured by JGC Catalysts and Chemicals Ltd.: CATALOID S-20L, a mean particle size of 17 nm, 10% by weight of SiO.sub.2) was diluted to a concentration of 3% by weight as SiO.sub.2, 35 g of an aqueous NaOH solution at a concentration of 3% by weight was added to adjust pH at 9.6. Moreover, after preparing an aqueous sodium silicate solution (diluted water glass) at a concentration of 3.0% by weight as SiO.sub.2 by diluting water glass (No. 3 sodium silicate manufactured by AGC Si-Tech Co., Ltd.), its dealkalization was performed by using a strongly acidic cation exchange resin (H type of SK1B, manufactured by Mitsubishi Chemical, Inc.) to prepare 889 g of an acidic silicic acid solution at a concentration of 3.0% by weight as SiO.sub.2. This acidic silicic acid solution was mixed with the diluted silicon dioxide sol adjusted of pH, 52 g of an aqueous NaOH solution at a concentration of 3% by weight was added to prepare a mixed slurry of the acidic silicic acid solution and the silicon dioxide sol, adjusted to pH of 9.6. To this, 154 g of an aqueous barium nitrate solution diluted with water was added as a component other than the silicon dioxide such that barium nitrate (manufactured by Wako Pure Chemical Industries, Ltd.) becomes 4% by weight as BaO, and then agitated for 15 min to prepare a mixed slurry.: Subsequently, the same method as that of Production method 1 was performed to prepare a classified dry product (9).

[0085] The resultant classified dry product (9) had particle size: 2.9 m, specific surface area: 170 m.sup.2/g and pore volume: 0.21 cm.sup.3/g.

Production Method 10

[0086] The classified dry product (1) was pulverized in a rotating ball mill for 2 hours to prepare a pulverized product (1).

[0087] For the classified dry products and the pulverized products prepared with the above-mentioned production methods, the following treatments were performed and they were used in Examples and Comparative Examples. The treatment methods and the properties of porous inorganic fillers used by Examples and Comparative Examples are shown below.

Porous Inorganic Filler (B-1)

[0088] The classified dry product (1) obtained with the production method 1 was calcinated at 400 C. for 3 hours in Ring Furnace (Denken Co., Ltd). The resultant filler was porous spherical (circularity: 0.96, particle size: 2.8 m, specific surface area: 170 m.sup.2/g, pore volume: 0.22 cc/g).

Porous Inorganic Filler (B-2)

[0089] The classified dry product (1) obtained with the production method 1 was calcinated at 800 C. for 3 hours Ring Furnace (Denken Co., Ltd). The resultant filler was porous spherical (circularity: 0.96, particle size: 2.8 m, specific surface area: 152 m.sup.2/g, pore volume: 0.21 cc/g).

Porous Inorganic Filler (B-3)

[0090] The classified dry product (1) obtained with the production method 1 was calcinated at 800 C. for 1 hour in Ring Furnace (Denken Co., Ltd). The resultant filler was porous spherical (circularity: 0.96, particle size: 2.8 m, specific surface area: 164 m.sup.2/g, pore volume: 0.22 cc/g).

Porous inorganic filler (B-4)

[0091] The classified dry product (2) obtained with the production method 2 was calcinated at 600 C. for 3 hours in Ring Furnace (Denken Co., Ltd). The resultant filler was porous spherical (circularity: 0.96, particle size: 2.8 m, specific surface area: 151 m.sup.2/g, pore volume: 0.18 cc/g).

Porous inorganic filler (B-5)

[0092] The classified dry product (3) obtained with the production method 3 was calcinated at 600 C. for 3 hours in Ring Furnace (Denken Co., Ltd). The resultant filler was porous spherical (circularity: 0.96, particle size; 2.8 m, specific surface area: 175 m.sup.2/g, pore volume: 0.21 cc/g).

Porous inorganic filler (B-6)

[0093] The classified dry product (6) obtained with the production method 6 was calcinated at 600 C. for 1 hour in Ring Furnace (Denken Co., Ltd). The resultant filler was porous spherical (circularity: 0.96, particle size: 2.8 m, specific surface area: 173 m.sup.2/g, pore volume: 0.21 cc/g).

Porous inorganic filler (B-7)

[0094] The classified dry product (7) obtained with the production method 7 was calcinated at 800 C. for 1 hour in Ring Furnace (Denken Co., Ltd). The resultant filler was porous spherical (circularity; 0.96, particle size: 2.8 m, specific surface area: 174 m.sup.2/g, pore volume: 0.22 cc/g).

Porous inorganic filler (B-8)

[0095] The classified dry product (8) obtained with the production method 8 was calcinated at 600 C. for 3 hours in Ring Furnace (Denken Co., Ltd). The resultant filler was porous spherical (circularity: 0.97, particle size: 2.8 m, specific surface area: 157 m.sup.2/g, pore volume: 0.18 cc/g).

Porous inorganic filler (B-9)

[0096] The classified dry product (9) obtained with the production method 9 was calcinated at 600*0 for 3 hours in Ring Furnace (Denken Co., Ltd). The resultant filler was porous spherical (circularity: 0.97, particle size: 2.8 m, specific surface area: 170 m.sup.2/g, pore volume: 0.21 cc/g).

Porous inorganic filler (B-10)

[0097] The classified dry product (1) obtained with the production method 1 was calcinated at 900 C. for 1 hour in Ring Furnace (Denken Co., Ltd). The resultant filler was porous spherical (circularity: 0.96, particle size: 3.5 m, specific surface area: 81 m.sup.2/g, pore volume: 0.13 cc/g).

Porous inorganic filler (B-11)

[0098] The pulverized product (1) obtained with the production method 10 was calcinated at 700 C. for 3 hours in Ring Furnace (Denken Co., Ltd). The resultant filler was a porous amorphous (circularity: 0.75, particle size: 2.1 m, specific surface area: 163 m.sup.2/g, pore volume: 0.22 cc/g).

Non-porous inorganic filler (B-12)

[0099] The classified dry product (1) obtained with the production method 1 was calcinated at 950 C. for 3 hours in the electric furnace. The resultant filler was non-porous spherical (circularity: 0.90, particle size: 1.9 m, specific surface area: 1 m.sup.2/g, and pore volume: less than 0.01 cc/g).

Porous inorganic filler (B-13)

[0100] The classified dry product (4) obtained with the production method 4 was calcinated at 600 C. for 1 hour in Ring Furnace (Denken Co., Ltd). The resultant filler was porous spherical (circularity: 0.96, particle size: 2.8 m, specific surface area: 149 m.sup.2/g, pore volume: 0.17 cc/g).

Porous inorganic filler (B-14)

[0101] The classified dry product (5) obtained with the production method 5 was calcinated at 600 C. for 1 hour in Ring Furnace (Denken Co., Ltd). The resultant filler was porous spherical (circularity: 0.96, particle size: 2.8 m, specific surface area: 161 m.sup.2/g, pore volume: 0.19 cc/g).

Silica Micro Bead P-500

[0102] Silica Micro Bead P-500 (manufactured by JGC Catalysts and Chemicals Ltd.) was porous spherical (circularity; 0.96, particle size: 1.7 m, and specific surface area: 130 m.sup.2/g, pore volume; 0.25 cc/g).

Silica Filler FUSELEX X

[0103] Silica Filler FUSELEX X (Tatsumori, Inc.) was non-porous amorphous (circularity: 0.51, particle size: 3.0 m, specific surface area: 7.96 m.sup.2/g, pore volume: less than 0.01 cc/g).

[0104] Production methods of the dental curable compositions used in Examples and Comparative Examples are shown below.

Example 1

[0105] A surface treatment was performed with -metacryloxy propyltrimethoxy silane to the porous inorganic filler (B-1). By using a double planetary mixer, 59 parts by weight of the surface-treated filler, 1 part by weight of AEROSIL R-972 (hydrophobized ultrafine particle silicon dioxide), and 40 parts by weight of the binder resin (A-1) were kneaded and vacuum-degassed to obtain a dental curable composition.

Example 2

[0106] A surface treatment for the porous inorganic filler (B-2) was performed by the same method as that of Example 1. This surface-treated filler was used to obtain a dental, curable composition by the same method as that of Example 1.

Example 3

[0107] A surface treatment for the porous inorganic filler (B-3) was performed by the same method as that of Example 1. This surface-treated filler was used to obtain a dental curable composition by the same method as that of Example 1.

Example 4

[0108] A surface treatment for the porous inorganic filler (B-4) was performed by the same method as that of Example 1. This surface-treated filler was used to obtain a dental curable composition by the same method as that of Example 1.

Example 5

[0109] A surface treatment for the porous inorganic filler (B-5) was performed by the same method as that of Example 1. This surface-treated filler was used to obtain a dental curable composition by the same method as that of Example 1.

Example 6

[0110] A surface treatment for the porous inorganic filler (B-6) was performed by the same method as that of Example 1. This surface-treated filler was used to obtain a dental curable composition by the same method as that of Example 1.

Example 7

[0111] A surface treatment for the porous inorganic filler (B-7) was performed by the same method as that of Example 1. This surface-treated filler was used to obtain a dental curable composition by the same method as that of Example 1.

Example 8

[0112] A surface treatment for the porous inorganic filler (B-8) was performed by the same method as that of Example 1. This surface-treated filler was used to obtain a dental curable composition by the same method as that of Example 1.

Example 9

[0113] A surface treatment for the porous inorganic filler (B-9) was performed by the same method as that of Example 1. This surface-treated filler was used to obtain a dental curable composition by the same method as that of Example 1.

Example 10

[0114] A surface treatment for the porous inorganic filler (B-10) was performed by the same method as that of Example 1. This surface-treated filler was used to obtain a dental curable composition by the same method as that of Example 1.

Example 11

[0115] A surface treatment for the porous inorganic filler (B-11) was performed by the same method as that of Example 1. By using a double planetary mixer, 59 parts by weight of the surface-treated filler, 1 part by weight of AEROSIL R-972 (hydrophobized ultrafine particle silicon dioxide), and 40 parts by weight of the binder resin (A-2) were kneaded and vacuum-degassed to obtain a dental curable composition.

Example 12

[0116] A surface treatment for the porous inorganic filler (B-1) was performed by the same method as that of Example 1. This filler was used to obtain a dental curable composition by the same method as that of Example 11.

Comparative Example 1

[0117] A surface treatment for the classified dry product (1) was performed with -metacryloxy propyltrimethoxy silane. This filler was used to obtain a dental curable composition by the same method as that of Example 1.

[0118] Comparative Example 2

[0119] A surface treatment for the porous inorganic filler (B-12) was performed with y-metacryloxy propyltrimethoxy silane. This surface-treated filler was used to obtain a dental curable composition by the same method as that of Example 1.

[0120] Comparative Example 3

[0121] A surface treatment for the porous inorganic filler (B-13) was performed with -metacryloxy propyl trimethoxy silane. This surface-treated filler was used to obtain a dental curable composition by the same method as that of Example 1.

[0122] Comparative Example 4

[0123] A surface treatment for the porous inorganic filler (B-14) was performed with -metacryloxy propyltrimethoxy silane. This surface-treated filler was used to obtain a dental curable composition by the same method as that of Example 1.

[0124] Comparative Example 5

[0125] A surface treatment for Silica Micro Bead P-500 was performed with -metacryloxy propyltrimethoxy silane. This surface-treated filler was used to obtain a dental curable composition by the same method as that of Example 1.

[0126] Comparative Example 6

[0127] A surface treatment for FUSELEX X was performed with -metacryloxy propyltrimethoxy silane. This surface-treated filler was used to obtain a dental curable composition by the same method as that of Example 1.

[0128] The characteristic test results of the dental curable compositions prepared by Examples and Comparative Examples are shown in Table 1.

TABLE-US-00001 TABLE 1A Property test results of dental curable compositions Example Example Example Example Example Example 1 2 3 4 5 6 Binder resins A-1 A-1 A-1 A-1 A-1 A-1 Inorganic Names B-1 B-2 B-3 B-4 B-5 B-6 fillers Shapes spherical spherical spherical spherical spherical spherical (B) porous porous porous porous porous porous Compositions SiO.sub.2/ZrO.sub.2 SiO.sub.2/ZrO.sub.2 SiO.sub.2/ZrO.sub.2 SiO.sub.2/ZrO.sub.2 SiO.sub.2/ZrO.sub.2 SiO.sub.2/TiO.sub.2 Combination 82/18 82/18 82/18 86/14 95/5 94/6 ratios (mass %) I.sub.1 0.85 1.24 1.00 1.28 0.65 1.29 I.sub.2 0.66 0.61 0.36 0.55 0.45 0.53 I.sub.1/I.sub.2 1.28 2.03 2.78 2.33 1.44 2.43 Contrast ratios 0.19 0.19 0.19 0.25 0.45 0.25 Bending Initial 145 151 159 152 153 144 strength (MPa) After 144 148 148 144 141 132 thermal cycling (MPa) Maintenance 99.3 98.0 93.1 94.8 92.0 91.7 rate of bending strengths (%) Example Example Example Example Example Example 7 8 9 10 11 12 Binder resins A-1 A-1 A-1 A-1 A-2 A-2 Inorganic Names B-7 B-8 B-9 B-10 B-11 B-1 fillers Shapes spherical spherical spherical spherical amorphous spherical (B) porous porous porous porous porous porous Compositions SiO.sub.2/TiO.sub.2 SiO.sub.2/BaO SiO.sub.2/BaO SiO.sub.2/ZrO.sub.2 SiO.sub.2/ZrO.sub.2 SiO.sub.2/ZrO.sub.2 Combination 97/3 88/12 93/7 82/18 82/18 82/18 ratios (mass %) I.sub.1 0.45 2.34 0.38 0.59 1.13 0.85 I.sub.2 0.29 0.82 0.28 0.20 0.45 0.66 I.sub.1/I.sub.2 1.55 2.85 1.35 2.95 2.51 1.28 Contrast ratios 0.45 0.34 0.47 0.19 0.30 0.30 Bending Initial 142 147 139 141 135 138 strength (MPa) After 129 135 126 127 122 130 thermal cycling (MPa) Maintenance 91.0 91.8 90.8 90.1 90.4 94.2 rate of bending strengths (%)

TABLE-US-00002 TABLE 1B Property test results of dental curable compositions Comparative Comparative Comparative Comparative Comparative Comparative Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Binder resins A-1 A-1 A-1 A-1 A-1 A-1 Inorganic Names classified dry B-12 B-13 B-14 Silica Micro FUSELEX X fillers product (1) Bead P-500 (B) Shapes spherical spherical spherical spherical spherical amorphous porous non-porous porous porous porous non-porous Compositions SiO.sub.2/ZrO.sub.2 SiO.sub.2/ZrO.sub.2 SiO.sub.2/ZrO.sub.2 SiO.sub.2/ZrO.sub.2 Si/ Si/ Combinations 82/18 82/18 65/35 99.5/0.5 100/0 100/0 ratios (mass %) I.sub.1 0.44 0.07 3.04 2.23 1.50 0.03 I.sub.2 1.47 0.02 1.31 1.22 1.22 0.11 I.sub.1/I.sub.2 0.30 3.50 2.32 1.83 1.23 0.27 Contrast ratios 0.19 0.19 0.51 0.52 0.56 0.68 Bending Initial (MPa) 128 113 153 154 121 125 strength After thermal 112 96 141 139 110 111 cycling (MPa) Maintenance 87.5 85.0 92.2 90.4 91.2 88.8 rate of bending strength (%)

Examples 1 to 12

[0129] It was recognized that for the inorganic fillers (B) in the dental curable compositions of Examples 1 to 12, the ratios (I.sub.1/I.sub.2) of a maximum absorbance (I.sub.1) at 3730 to 3750 cm.sup.1 to a maximum absorbance (I.sub.2) at 3000 to 3600 cm.sup.1 in the infrared absorption spectrum, are not less than 1 and not more than 3.

[0130] The dental curable compositions of Examples 1-12 were recognized to exhibit excellent contrast ratios, and have a contrast ratios capable of reproducing the color tone of natural teeth. Furthermore, since the mechanical strengths of the dental curable compositions of Examples 1 to 12 are high values for bending strengths at the initial and after the thermal cycling, the dental curable compositions were recognized to have excellent mechanical strengths and the durability on aged deterioration.

Comparative Example 1

[0131] Although the dental curable composition of the Comparative Example 1 has a contrast ratio capable of reproducing the color tone of natural teeth, the above-mentioned ratio I.sub.1/I.sub.2 of the inorganic filler (B) was no more than 1. Therefore, it was recognized that its bending strength after the thermal cycling was low and its durability on aged deterioration was poor although its initial bending strength was high.

Comparative Example 2

[0132] Although the dental curable composition of the Comparative Example 2 has a contrast ratio capable of reproducing the color tone of natural teeth, the shape of the inorganic filler (B) is non-porous and thereby its initial bending strength was recognized to be low. Furthermore, since the above-mentioned ratio of the inorganic filler (B) was not less than 3, its durability on aged deterioration was also recognized to be poor.

Comparative Examples 3 to 5

[0133] Since the I.sub.1/I.sub.2 of inorganic fillers (B) for the dental curable compositions of Comparative Examples 3-5 were not less than 1 and not more than 3, the durabilities on aged deterioration were excellent. However, their contrast ratios were high and the dental curable compositions were opaque, and thereby it was recognized to be difficult to reproduce the color tone of natural teeth.

Comparative Example 6

[0134] The dental curable composition of Comparative Example 6 had a high contrast ratio and was opaque, and thereby it was recognized to be difficult to reproduce the color tone of natural teeth. Moreover, since the above-mentioned ratios I.sub.1/I.sub.2 of the inorganic filler (B) was not more than 1, it was recognized that the bending strength at the initial and after the thermal cycling were low, and its durability on aged deterioration was also recognized to be poor.