JPS63303906A - Artificial dental material - Google Patents

Abstract

PURPOSE:To obtain an artificial dental material having excellent mechanical strength, good appearance and forming roentgenogram, by blending specific alumina fine powder with a specific filler having roentgenogram forming properties, a specific polymerizable and a polymerization initiator in a specific ratio. CONSTITUTION:(A) Alumina fine powder having 1.60-1.70 refractive index (nA), 0.005-0.1mum particle diameter, 3-300m<2>/g specific surface area and consists of preferably gamma-, eta-, delta- and/or theta-alumina crystal phase is blended with (B) an inorganic filler having roentgenogram forming properties, 1.50-1.60 refractive index (nF), 0.1-100mum particle diameter and 0.2-20mum average particle diameter, (C) a polymerizable monomer having 1.50-1.60 refractive index (nP) after curing and (D) a polymerization initiator as constituent elements and relationship between the components A-C shown by formula I-formula II (WA, WF and WM are blending weight of the components A, B and C, respectively) and further relationship shown by nA>nF>nP are formed to give an artificial dental material which can be replaced with any part of natural tooth and has the above- mentioned effects.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an artificial tooth material that can partially or completely replace natural teeth in the field of dentistry.

(Prior Art) Composite resins made of polymerizable monomers, inorganic fillers, and polymerization initiators are now widely used as artificial tooth materials for filling and repairing tooth defects, such as cavities. . Early composite resins were 1-10
It is a composite of a 0 μm inorganic filler and a polymerizable monomer, and because of its transparency and color tone, which are close to those of natural teeth, it has been widely used for filling and repairing defects in anterior teeth.

However, its mechanical strength, such as compressive strength, hardness, and wear resistance, is inferior to that of natural teeth, and it is often used for applications that require high mechanical strength, such as filling teeth, filling molars, and forming crowns. It was unsuitable for such applications.

The basic problem with dental composite resins is the physical and chemical properties of the IJx phase and the inorganic filler phase, such as hardness, Young's modulus, and wear resistance. There are fundamental differences in properties, coefficient of thermal expansion, water absorption, etc. In other words, differences in hardness cause a decrease in polishing gloss, and differences in Young's modulus, coefficient of thermal expansion, and water absorption cause internal stress at the matrix-filler interface.
Accelerates the decline in material strength. It has also been pointed out that the low abrasion resistance of the IJ x phase reduces the abrasion resistance of the entire composite resin (Japanese Journal of Cavernology, 5).
2, pp. 195-209, 1985).

Special Publication Sho 57-500150, Japanese Patent Publication Sho 57-82303
And in JP-A-57-120506, in an attempt to improve these problems, the matrix phase was
A technique has been proposed to reduce the difference in physical and chemical properties as much as possible between the coarse inorganic filler phase and the coarse inorganic filler phase with a particle size of 1 μm or more by composite reinforcement with ultrafine inorganic filler particles with a particle size of 1 μm or less. Composite resins using this technology are called hybrid composite resins, and today they have come to dominate the range of composites for filling and restoring molars.

With the advent of hybrid composite resin, hardness has improved.
Mechanical strengths such as compressive strength and abrasion resistance have improved, and the range of applications for dental composite resins has expanded from anterior teeth to molars.

(Problems to be Solved by the Invention) However, even with this type of improved composite range, some problems still remain. One of them is the loss of aesthetics due to decreased transparency. The above-mentioned known document discloses silica, alumina, and titanium oxide as materials for the ultrafine particle filler, but only amorphous silica is used in the publicly used vibrator (written-lit type composite resin). When a hybrid composite resin is prepared using amorphous silica and a coarse inorganic filler that has X-ray contrast properties in order to impart the X-ray contrast properties required for molar restoration materials, its transparency The refractive index of amorphous silica is 1.46, while the refractive index of an inorganic filler with X-ray contrast properties is 1.46. This is because light scattering inside the composite resin increases due to this difference in refractive index.The second problem is as follows.
It has mechanical strength. Strengthening of the matrix phase with ultrafine silica has made it possible to apply it to molars, but its scope of application is still limited to filling first-grade cavities, and it is not mechanical enough to replace the molar cusp or the entire crown. At present, no improvement in strength has been achieved. The third problem is polishing gloss. Although the polishing gloss has improved compared to early composite resins, it is far below the level of natural teeth or porcelain teeth.
That is, a technique for creating a composite resin that has all of mechanical strength, transparency, polishing gloss, and X-ray contrast properties is not yet known. If a composite resin with these various properties were to be realized, it would not only be useful for filling and restoring cavities, but also for the production of inlays, onlays, crowns, and dentures.
It is extremely useful as an artificial tooth material that can partially or completely replace natural teeth, such as veneer resin, laminate veneers, and abutment teeth.

(Means for Solving the Problem) The present inventors have further improved the excellent mechanical strength and polishing gloss of the hybrid composite resin, and have achieved an X-ray contrast property comparable to that of natural teeth. As a result of our extensive efforts to create artificial tooth materials that maintain transparency and are comparable to natural teeth, we have developed fine alumina powder with a specific refractive index and particle size, and alumina powder with a specific refractive index and particle size. And X-
By polymerizing and curing a composition in which an inorganic filler with linear contrast properties and a polymerizable monomer with a specific refractive index are mixed in a specific mixing ratio, a desired artificial tooth material can be achieved. I found it.

That is, the present invention provides an artificial tooth material comprising fine alumina powder, an inorganic filler, a polymerizable monomer, and a polymerization initiator as components, (1) the fine alumina powder has a refractive index (nA) of 1.60 to
1.70, and the particle size range is 0.0
05~0.1μm, specific surface area 30~300rI! /
2, (2) the inorganic filler is a filler having X-ray contrast properties, and its refractive index (nF) is 511.50 to 1.65.
and the particle size range is 0.1 to 100μ
m, the average particle size is 0.2 to 20 μm, (3)
The refractive index (nP) of the polymerizable monomer after curing is from 1.50 to
1.60, and (4) blending weight (WM) of the polymerizable monomer> and blending weight (WA) of the alumina fine powder.
) and the blended weight (WF) of the inorganic filler.

The most important feature of the present invention is the use of fine alumina powder having a refractive index in the range of 1.60 to 1.70. In addition to α-alumina, alumina contains γ, 6%, 1%, p, η,
Crystal modifications such as θ are known, and the refractive index of α-alumina is 1.76 to 1.768, while the refractive index of these crystal modifications is in the range of 1.60 to 1.70. .

Ultrafine powder of amorphous silica is used to strengthen the matrix of hybrid composite resins, but in terms of mechanical strength, sialumina is superior to amorphous silica, so ultrafine alumina powder is used. It is expected that the hybrid composite resin prepared in this way will exhibit better mechanical strength. Japanese Patent Publication No. 57-8230
3 and JP-A-57-120506 disclose the use of alumina, but do not describe its crystal modification at all. As mentioned above, 1-alumina has many crystal modifications, each having a different refractive index.

Generally speaking, alumina means α-alumina, and α
-Alumina is widely used in industrial fields.

Therefore, when a hybrid composite resin is prepared using ultrafine α-alumina powder, the resin loses its transparency and faces the problem that it cannot be used for aesthetic dental crown restoration. This is due to the difference in refractive index, as the refractive index of α-alumina, 1.76 to 1.768, is too large compared to the refractive index of methacrylate polymers, 1650 to 1.60, used in dental composite ranges. This is because light scattering increases.

The inventors of the present invention have conducted intensive studies to create a hybrid composite resin that takes advantage of the strength of alumina and has excellent transparency.
We came up with the idea of using ρ, η, θ type alumina for χ, and discovered that transparency can be maintained if the refractive index is in the range of 1.60 to 1.70. It is essential that the alumina used in the present invention has a refractive index in the range of 1.60 to 1.70, and there are no particular restrictions on the crystal form. Therefore, as long as the refractive index is in the range of 1.60 to 1.70,
Each of the crystal phases of ρ, 1, and θ may be present alone in γ, δ, χ, or these crystal phases may be mixed together.

Furthermore, the presence of a small amount of α-phase is also allowed.

The transparency of a composite resin depends not only on the difference in refractive index between the filler and the resin matrix but also on the particle size of the filler. In other words, the scattering of light increases when the wavelength of the light and the particle size are close to each other, and conversely, the scattering of light decreases as the wavelength of the light and the particle size get closer. That is, by using particles with a size far from the visible light range of 0.4 μm to 0.7 μm, even if there is a difference in the refractive index between the filler and the matrix, the degree of light scattering can be reduced and transparency can be maintained. I can do things. Therefore, the alumina fine powder used in the present invention preferably has a particle size in the range of o, oos to 0.1 μm and a specific surface area in the range of 30 to 300♂/2. If the particle size exceeds 0.1 μm and the number of particles near the visible region increases, the transparency decreases beyond the permissible limit, which is not preferable. On the other hand, if the number of particles with a particle size smaller than o, oos μm increases, the viscosity of the composite resin will increase significantly, resulting in a decrease in the amount of filler. Measurement is performed using the immersion method using the D line of the lamp (5890-96 people) as a light source. Identification of the crystalline phase can be achieved by comparing the X-ray diffraction pattern with the known data described, for example, on pages 27-28 of "Catalyst Handbook by Element" (edited by the Catalyst Society, published by Jirokushokan, 1967). The particle size range can be easily determined by electron microscopic observation, and the specific surface area can be measured according to the BET method.

The alumina used in the present invention is obtained by a method of burning aluminum chloride in the vapor phase, hydrolysis of an organic aluminum salt, or alumina aqueous gel obtained by spark discharge in aluminum water at 400 to 1000°C.

Fine alumina powder is usually surface treated before being blended with other components. As the surface treatment agent, a silane coupling agent, an organic titanate coupling agent, an organic aluminum coupling agent, etc. are used. Among them, preferred coupling agents are those having a functional group copolymerizable with the polymerizable monomer, such as vinyltrichlorosilane, vinyltriethoxysilane, γ-
Methacryloxypropyltrimethoxysilane, γ-mercabutoglobyltrimethoxysilane, isopropylisostearoyldiacryl titanate, tetra(2,2-
Examples include diallyloxymethyl-1-butyl)bis(di-tridecyl)phosphite titanate. Surface treatment is performed using these coupling agents in an amount of 95 to 100 parts by weight per 100 parts by weight of alumina fine powder.

The material of the inorganic filler used in the present invention has X-ray contrast properties and has a refractive index (defined in the section of fine alumina powder) of 1.5.
It is limited to those in the range of 0 to 1.65. X@1 contrast properties, which are meaningful for dental diagnosis, are defined as "X-ray contrast properties equivalent to or better than an aluminum plate of the same thickness as the test material," and inorganic fillers that provide such contrast properties are Generally contains heavier elements than potassium. for example,
Examples include calcium 1 titanium 71 iron 1 zinc, strontium, zirconium, tin, barium, lanthanum, cerium, hafnium, and tungsten. on the other hand,
In order to maintain the transparency of the composite resin, the refractive index of the inorganic filler is the refractive index of the alumina fine powder used in the present invention, 1.60 to 1.70, and the refractive index of the cured polymerizable monomer, 1.50. It is essential to take a value close to ~1.60. The acceptable range is 1.50 to 1.65, preferably 1.53 to 1.60. As an inorganic material that satisfies the above conditions, strontium borosilicate glass (nF = 1.50. Ray -8orb@
) T-4000, Kimple), barium borosilicate
) Crow (nF=1.553.Ray-8orbT-
3000, Kimple), barium silicate glass (n
F= 1.58゜Ray -5orb” T -200
0, Kimple), lanthanum glass ceramics (nF=
1.563. GM31684. In addition to glass materials such as Schott), hydroxyapatite (nF = 1.61 ~
1.63) Calcium phosphate (nF=1.63),
Water-insoluble inorganic salts such as calcium pyro-IJ phosphate (nF=1.60) are also suitably used.

The particle size range of the inorganic filler is 0.1 to 100 μm, and the weight average particle size is required to be in the range of 0.2 to 20 μm. The particle size range and weight average particle size can be easily measured by a light transmission centrifugal sedimentation method (combined with natural sedimentation). When the number of particles with a particle size exceeding 100 μm increases, the composite resin paste becomes rough, and the workability and shape reproducibility (t or restorability) in adjusting the shape of teeth deteriorate. If the number of particles with a particle size of less than 0.1 μm increases, it becomes impossible to achieve the high strength mechanical properties that are a feature of the hybrid type. The average particle size is 0.2 to 20 μm, preferably 0.
．． An artificial tooth material that can sufficiently achieve the purpose of the present invention can be obtained at a thickness of 5 to 10 μm.

The inorganic filler having the above particle size can be easily produced by a known pulverization method or a solution reaction precipitation method, and its shape may be crushed, spherical, scaly, etc., and is not particularly limited. .

The inorganic filler is usually subjected to an appropriate surface treatment, and then
Mixed with other components. As a surface treatment agent, a coupling agent used for surface treatment of fine alumina powder is preferably used, and the amount used is 100 parts by weight of inorganic filler, 0
．． 1 to 10 parts by weight of the polymerizable monomer used in the present invention exists in a cured product having a refractive index of 1.50 to 1.60. Refractive index is 1.5
If the amount is less than
The aesthetic level of artificial teeth cannot be maintained. On the other hand, the upper limit is theoretically permissible up to around 1.7, but due to technical limitations with (meth)acrylate polymerizable monomers [meaning methacrylates and acrylates] commonly used in dental composite resins, The limit is 1.60. Polymerizable monomers that are preferably used are (meth)acrylates, and the following are exemplified.

Methyl (meth)acrylate, ethyl (meth)acrylate, lauryl (meth)acrylate, benzyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate,
Ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, neobentyl glycol di(meth)acrylate, l,6-hexanethiol di(meth)acrylate, 1,10-decanediol dimethacrylate, bisphenol A Di (meta)
Acrylate, 2,2-bis[(meth)acryloyloxypolyethoxyphenyl]furopane, 2,2-bis(
4-(3-acryloyloxypropoxy)phenyl]
Prohaf, 2,2-bis[4-(3-methacryloyloxib aboxy)phenyl]propane (Bis-G
(sometimes referred to as MA), 1,2-bis[3-methacryloyl-2-hydroxypropoxy]ethane,
2.24-) Addition compounds of dimethylhexamethylene diisocyanate and 2-hydroxyethyl (meth)acrylate or glycerin di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate.

These polymerizable monomers can be used alone or as a mixture of several types, and the cured product has a refractive index of 1.50 to 1.50.
The composition must be selected to fall within the range of 1.60. For example, methyl methacrylate is a cured product, that is, P
Since the refractive index of MMA is 1.48, it is always Big.
- Must be used in mixture with a high refractive index monomer such as GMA (n = 1.55).

The polymerization initiator used in the present invention is not particularly limited and may be any known one, but is usually selected in consideration of the polymerizability of the polymerizable monomer and the polymerization conditions. For example, when thermally polymerizing (meth)acrylate, organic peroxides such as benzoyl peroxide, di-t-butyl peroxide, cumene hydroperoxide, 2.2-
Azo compounds such as azobisisobutyronitrile and 1,1'-azobis(cyclohexane-1-carbonitrile) are preferably used. On the other hand, when performing room temperature polymerization,
Benzoyl peroxide/dimethylaniline type, cumene hydroperoxide/thiourea type, ascorbic W
In addition to oxidation-reduction initiators such as 1/ Cu" + base, organic sulfinic acid (or its salt)/amine/peroxide system, tributylborane, organic sulfinic acid, etc. are also suitably used. On the other hand, visible In the case of photopolymerization by light irradiation, oxidation-reduction systems such as α-diketone/tertiary amine, α-diketone/aldehyde, α-diketone/mercaptan, etc. are preferred.As the α-diketone, camphorquinone, diacetyl, 2,3-penta/dione, benzyl,
Tertiary amines such as acenaphthenequinone and phenanthraquinone; tertiary amines such as N,N-dimethylaminoethyl methacrylate), ethyl N,N-dimethylaminobenzoate, and Michler's ketone; aldehydes such as citronellal,
Examples of the mercaptan include lauryl aldehyde, O-7 taldialdehyde, and p-octyloxybenzaldehyde, and 1-decanethiol, thiosalicylic acid, 2-mercaptobenzoxazole, and 4-mercaptoacetophenone. Furthermore, an α-diketone/organic peroxide/reducing agent system in which an organic peroxide is added to these oxidation-reduction systems is also preferably used. When performing photopolymerization by ultraviolet irradiation, the above-mentioned visible light rays such as henzine methyl ether, benzyl dimethyl ketal, benzophenone, 2-methylthioxanthone, diacetyl, pemetal, azobisisobutyronitrile, tetramethylthiuram disulfide, etc. Polymerization initiators are also suitably used.

The appropriate amount of these polymerization initiators added is in the range of 0.01 to 10% based on the polymerizable monomer.

In addition to the above essential components, additives such as pigments, ultraviolet absorbers, fluorescent agents, and polymerization inhibitors, or organic-inorganic composite fillers as disclosed in JP-A-56-49311 may be added depending on the application. It is also allowed.

The alumina fine powder, inorganic filler, and polymerizable monomer used in the present invention are kneaded in a specific range of ratios. Since the mixed system consisting of alumina fine powder and polymerizable monomer becomes the matrix phase for the inorganic V2, the mixing ratio of alumina fine powder and polymerizable monomer, WA/WM, and the ratio of inorganic filler to matrix phase WF / (WA + WM ) affect the performance of composite resins. That is, WA/W
When M is 0.3 or less, the reinforcement of the matrix phase is insufficient,
Poor mechanical strength and polishing gloss of composite resin.

On the other hand, when WA/WM is 4 or more, the viscosity of the matrix phase increases significantly and crosstalk becomes difficult. The preferred range is 3)
WA/WM) l.

When WF/(WA+WM) is less than 0.5, the reinforcing effect by the inorganic filler is insufficient and the mechanical strength is low, and when it is more than 10, crosstalk becomes difficult due to increased viscosity. A very preferable range is 5)Wir/(WA+WM)>1.

The mixture of alumina fine powder, inorganic filler, and polymerizable monomer of the present invention is liquid or paste-like, but is solidified by polymerizing the polymerizable monomer. The transparency of the obtained solid was 1.60-1.
70, 1.50 to 1.65. If it is in the range of 1.50 to 1.60, the minimum required level can be secured as an artificial tooth material, but if the inequality n^> nF > np is satisfied. can ensure a high degree of transparency.

By the way, since the artificial tooth material of the present invention has a wide variety of uses, it is provided to users in a processed state suitable for each use. A specific example will be shown below.

(1) In the visible light polymerization type of dental composite resin used as a filling and restorative material for cavities, a paste obtained by kneading all ingredients at once is filled into a light-shielded container and provided to the user. . After filling the cavity or applying it on the tooth surface, the user irradiates the paste with visible light to harden the paste.

In the cold polymerization type, two pastes containing separate oxidizing agents and reducing agents of the oxidation-reduction catalyst are mixed and provided to the user as a pair. After mixing the two pastes uniformly, the user immediately fills the cavity or applies it to the tooth surface and waits for it to harden through chemical polymerization.

(2) Composite resin for abutment tooth construction Provided to users in the two types of packaging described in (1). The curing method (1
) Same as (8) Materials for veneers and dental crowns such as inlays and crowns Visible light and/or ultraviolet light polymerization initiator In some cases, high temperature to medium temperature room polymerization initiator is included.

1 base) K crosstalk and provide it to the user. The user applies the paste on a metal frame or a tooth model, adjusts the shape, and then irradiates it with visible light and/or ultraviolet light to harden it. After photocuring, the polymerization may be further accelerated by heating.

(4) Denture material A composition containing a visible light polymerization initiator or/and an ultraviolet light polymerization initiator or/and a high to medium temperature polymerization initiator is filled into a metal denture, and visible light or/and ultraviolet light or/and heating is performed. harden by Thus, a shaped denture is provided to the user.

(Function) In the present invention, the polymerizable monomer hardens together with the alumina fine powder to form a high-strength matrix phase. In other words, when the organic matrix (IJ) phase consisting only of polymerizable monomers is introduced with alumina fine powder, it is converted into the organic-inorganic composite (IJ) phase at the molecular level and undergoes physical and chemical modification. receive. M) By bringing the mechanical properties, thermal expansion coefficient, and water absorption of the IJTx phase closer to those of the coarse inorganic filler phase, the heterogeneity between the two phases is reduced, and this improves the mechanical strength of the composite resin. , abrasion resistance, polishing gloss, etc. are improved. These improvement effects are clearly greater than when amorphous silica fine powder is used, as shown in Japanese Patent Publication No. 57-500150. This is due to the fact that alumina surpasses amorphous silica due to mechanical properties. attributed to.

Furthermore, amorphous silica fine powder exhibits the effect of lowering the refractive index of the matrix phase, whereas alumina fine powder exhibits the effect of increasing the refractive index. In general, an inorganic filler with X-ray contrast properties has a refractive index (1,50 to 1.65) that is equal to or higher than that of the matrix phase resin, so alumina fine powder with a refractive index of 1.60 to 1.70 The introduction of
The refractive index of the IJTx phase is kept close to the refractive index of the filler, so that the transparency of the composite resin is not impaired. On the other hand, amorphous silica fine powder (refractive index: 1.46) and α-alumina (
Refractive index: 1.76-1.77) separates the refractive index of the matrix phase far from the refractive index of the filler, reducing the transparency of the composite resin.

(Effects) The artificial tooth material obtained by the present invention has mechanical strength, aesthetic properties (transparency and gloss), excellent KX-ray contrastability, and is therefore as effective as natural teeth. It is also possible to replace the parts. Its uses are wide-ranging, including filling restorations for cavities in anterior and molar teeth, building abutment teeth, making inlays, onlays, and crowns, and as a material for making dentures.

(Examples) Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples. The definitions of various quantities related to the properties of the materials shown in the examples and the methods for measuring them are as follows.

(1) Average particle diameter and particle diameter range Regarding the alumina fine powder, the particle diameter range was determined based on transmission electron micrographs.

The inorganic filler was measured using an automatic particle size distribution measuring device CAPA500 manufactured by Kaiyo Seisakusho. The measurement principle is a light transmission centrifugal sedimentation method (combined with natural sedimentation).

(2) Identification of crystal phase of alumina X-ray diffraction patterns were measured using an X-ray crystal analyzer. The resulting pattern was published in the “Element Side Catalyst Handbook” (Jijin Shokan,
It was determined by comparing and contrasting the data with the data described in Catalysis Society (ed., 1967, pp. 27-28).

(8) Measurement of specific surface area of alumina Measurement was carried out using Canterthorpe QS-13 model manufactured by Yuasa Ionics ■. The measurement principle is the BET method.0 (4) Measurement of refractive index The refractive index of alumina and inorganic filler is measured using Atsube's refractometer using the D line of a sodium lamp as a light source. /, methyl salicylate, dimethylformamide, etc. as a solvent and measured by the immersion method. The refractive index of the polymerizable monomer after curing is 5XIO■ A test piece formed into a rectangular parallelepiped measuring 20 m in diameter was measured using an Atsube refractometer.

(6) Compressive Strength Paste-like artificial tooth materials were polymerized and hardened by a predetermined method and then immersed in water at 37° C. for 24 hours to prepare test pieces. The test piece had a cylindrical shape with a diameter of 4 mm and a height of 4 mm, and the compressive strength was measured using an Instron universal testing machine at a crosshead speed of 2 mm/min.

(6) Bending strength A paste-like artificial tooth material was polymerized and hardened by a predetermined method and then immersed in water at 37° C. for 24 hours to prepare a test scissors piece. The shape of the test piece was a rectangular parallelepiped measuring 2 x 2 m x 30 cm, and a three-point bending test was performed with a distance between fulcrums of 25 cm using a diinstron universal testing machine at a crosshead speed of 1 wm /
Bending strength was measured in in.゛(γ) Transparency A paste-like artificial tooth material was molded into a disc shape of 20 mmφ x 0.85 s+s, and this was used as a test piece.

The evaluation method used a color meter (Nippon Denshokusha Σ500 model).
Difference ΔL between the lightness (Ll) when chromaticity is measured by placing a standard white board behind the test piece and the lightness (L2) when chromaticity is measured by placing a standard blackboard behind the same test piece: L1-
Measure L2 and use it as an index of transparency.In this evaluation method, Δ
The larger the value of L, the higher the transparency.

(8) Amount of toothbrush wear A paste-like artificial tooth material was polymerized and hardened by a predetermined method, and then immersed in water at 37° C. for 24 hours to prepare a test piece. The test piece was in the form of a plate measuring 20cm x 30w x 2m.The test surface was polished with +1500 emery paper and then finished polished using a dental polishing disc (Raflex Fine manufactured by 3M Company). On the test surface, 2
00? After sliding and wearing a toothbrush for 5,000 m under a load of , Δvol (%), were calculated and used as the amount of toothbrush wear.

(9) A test piece (15 x 25
X2■). First, remove approximately 0.1 inch of the surface layer of the test piece with +500 emery paper and use this as a rough polished surface.
Next, this surface was subjected to semi-finish polishing using a Shofu White Point, and then final finishing polishing was performed using a Shofu Silicon Point or a 3MM dental polishing disc (Noflex Fine).

Gloss was measured by the following method. Using a variable angle gloss meter VG-107 manufactured by Nippon Denshoku Industries, the projection angle was 60° and the receiving angle was 60°.
Adjust the area where the sample is irradiated to a circular shape with a diameter of 13°, and measure the intensity (relative value) of the light specularly reflected by the polished surface, assuming that the intensity of the reflected light is 100 when the mirror is used as the test piece. It was used as an index of surface gloss.

X-ray contrast pasty artificial tooth material is placed in a mold for creating a disc-shaped test piece with a diameter of 15 cm and a thickness of 2.0 mm, polymerized and hardened using a prescribed method, and then removed from the mold. The specimen removed from the specimen was used as a test piece. Place the X-ray film on a lead sheet with a thickness of 2.0 mm or more and place a test piece in the center of the film, and an aluminum plate with the same dimensions and a thickness of 2.0 mm (purity of 99.5% or more).
put 40 on specimen, aluminum and X-ray film
c! A tube voltage of 5 Q kVpOX rays are irradiated from a distance of II. The irradiation time shall be an appropriate time so that the image of the test specimen, the surrounding film portion, and the aluminum plate portion will appear completely when developed. After development and fixing, the density of the image on the test piece was compared with the image on the aluminum plate, and those darker than the aluminum plate were judged to be good, and those lighter than the aluminum plate were judged to be poor.

Example 1 Lanthanum glass ceramics manufactured by Schott (0M316
84> was ground with a vibrating ball mill, and the particle size range was 0.1
A fine powder of ~20 μm and an average particle size of 2.8 μm was obtained.

1 part by weight of γ-methacryloxypropyltrimethoxysilane was used for 100 parts by weight of this powder to illegally surface-treat the powder to obtain an inorganic filler (this will be referred to as filler F-1).

The refractive index (nF') of this material was 1.56. Average particle size o, 02. Ultrafine particle alumina (Aluminum Oxide C■ manufactured by Nippon Aerosil Co., Ltd., the crystal phase of which is a mixture of δ phase and θ phase) having a ums specific surface area of 100 j/f and a refractive index (nA) of 1.65 was first used. Similarly,
100 parts by weight of this powder was subjected to surface treatment using 25 parts by weight of γ-methacryloxyglobyl trimethoxysilane, and ultrafine alumina filler (this was used as filler A).
−1) was obtained.

As polymerizable monomers, 50 parts by weight of bisphenol A polyethoxy dimethacrylate (hereinafter referred to as D-2,5), 1 mole of 2,2.4-)dimethylhexamethylene diisocyanate, and 2 moles of glycerin dimethacrylate. 25 parts by weight of adduct (hereinafter referred to as U-4TH), triethylene glycol dimethacrylate (hereinafter referred to as 3G)
25 parts by weight and camphorquinone (as a photopolymerization initiator)
(hereinafter referred to as CQ) 0.5 parts by weight 4- Ethyl N,N-dimethylaminobenzoate (hereinafter referred to as EDMAR) 1
,0 parts by weight were mixed. The refractive index ("p) of this polymerizable monomer after curing was 1.541. Inorganic filler 250 parts by weight (WF), alumina fine particle filler 15
0 parts by weight (WA), 100 parts by weight of polymerizable monomer (WM
) After mixing and kneading at a ratio of
A paste-like artificial tooth material was obtained. For this paste,
Visible light irradiator (Kulzer $IDentacolo
The physical properties of the cured product obtained by irradiating it with light for 90 seconds were measured, and the following results were obtained: 0 compressive strength 4550 kf/i, bending strength 1400 kf/cli, transparency (ΔL) 38. Surface gloss after polishing 54% (excellent), toothbrush 111 mm @ (Δvol)' 0.03% s
The X-ray contrast property was good.

Examples 2 to 6 and Comparative Examples 1 to 6 Barium silicate glass ("F=1.58. Ray
-8orb■T-2000, Kimple) was crushed in a vibrating ball mill to obtain an inorganic powder having a particle size range of 0.1 to 20 μm and an average particle size of 2.5 μm. An inorganic filler was obtained by illegally surface-treating 100 parts by weight of this powder using 1 part by weight of γ-methacryloxypropyltrimethoxysilane. This is referred to as filler F-2. Barium borosilicate glass (nF=1.53.Shoku)
0M278840) was pulverized in the same manner as the above filler to obtain a powder having a particle size range of 0.1 to 20 μm and an average particle size of 3.3 μm. Surface treatment was performed in the same manner as above, and this inorganic filler was designated as F-3. Strontium borosilicate glass (IJr=l, 5Q, Ray-8orbOT-
4000, Kimple) was crushed in the same manner as the above filler, and the particle size range was 0.1 to 20 μm and the average particle size was 2.9.
The inorganic filler obtained by surface-treating the μm powder in the same manner as above is designated as F-4. Borosilicate glass ("F=1.
48. Pyrex glass, Dow Corning) was crushed in the same way as the above filler, and the particle size range was 0.1 to 2.
F-5 is an inorganic filler that has been surface-treated in the same manner as above for powder with an average particle size of 3.0 μm and 0 μm.Aluminum oxide C■ manufactured by Nippon Aerosil Co., Ltd. used in Example 1 was heated at 1250°C. It was baked for 2 hours. The crystalline phase of the alumina fine powder thus obtained was an α phase, with a specific surface area of 32 rl/f, a maximum particle size of 0.1 μm or less, and a refractive index (nA) of 1.75 to 1,77. This was subjected to surface treatment using 10 parts by weight of γ-methacryloxypropyltrimethoxysilane to 100 parts by weight of the above powder, and ultrafine alumina filler (this was used as filler A-
2) was obtained.

Average particle size 0.0 A ttms specific surface area 50 m”/r,
Ultrafine particle silica (manufactured by Nippon Aerosil Co., Ltd., ox-so) with a refractive index (nA) of 1.45 was surface-treated using 15 parts by weight of γ-methacryloxypropyltrimethoxysilane to form an ultrafine silica filler ( This is ficy-A
-3) was obtained.

A paste was prepared using these inorganic fillers, the inorganic filler F-1 used in Example 1, and the alumina fine powder filler A-1 using the polymerizable monomers listed in Table 1, and the physical properties after curing were measured. The results are shown in Table 1.2. The photopolymerization catalyst and polymerization method used were the same as in Example 1, except for Comparative Example 4.

Claims (3)

[Claims] (1) In an artificial tooth material containing fine alumina powder, an inorganic filler, a polymerizable monomer, and a polymerization initiator, (a) the fine alumina powder has a refractive index (n_A) of 1.60 to
1.70, and the particle size range is 0.00
5 to 0.1 μm and a specific surface area of 30 to 300 m^2/g; (b) the inorganic filler has X-ray contrast properties and its refractive index (n_F) is in the range of 1.50 to 1.65; and the particle size range is 0.1 to 100 μm, and the average particle size is 0.1 to 100 μm.
2 to 20 μm, and (c) the refractive index (n_P) of the polymerizable monomer after curing is 1
．． 50 to 1.60, and (d) between the blended weight of the polymerizable monomer (W_M), the blended weight of the alumina fine powder (W_A), and the blended weight of the inorganic filler (W_F). , the following two relational expressions: 4>W_A/W_M>0.3 10>W_F/(W_A
An artificial tooth material characterized in that +W_M)>0.5 holds true. (2) Alumina fine powder is γ-alumina, η-alumina,
The artificial tooth material according to claim 1, which is an alumina fine powder composed of a crystalline phase of δ-alumina and/or θ-alumina. (3) n_A>n_ between n_A, n_F and n_P
The artificial tooth material according to claim 1, in which the relational expression F>n_P holds true.