JPH023765B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing a dental crown material having transparency. Specifically, when manufacturing a dental crown material by polymerizing a polymerizable monomer in the presence of a crosslinkable polymer, the refractive index of the crosslinkable polymer and the refractive index of the polymer obtained by polymerizing the polymerizable monomer are determined. The difference between
Provided is a method for manufacturing a dental crown material using a polymerizable monomer having a concentration of 0.01 or less. Traditionally, veneers and jacket crowns are widely used in the dental industry. A veneer crown is generally a cast metal crown with resin built up on the surface. For example, first, an opaque layer with good adhesion is formed in contact with the metal casting crown, then a dentin layer is formed to reproduce the natural color tone of the upper layer of the opaque layer, and finally, a dentin layer is formed to reproduce the transparent color and the dentin It is used in a form with an enamel layer formed to protect the layer. A jacket crown is used in the form of a metal cast crown or a resin crown with the above-mentioned opaque layer, dentin layer, and enamel layer successively built up. Each layer is generally formed by preparing a powdered resin component and a liquid or paste monomer component separately, kneading them, and polymerizing the monomer components. Therefore, the kneading of the powdered resin component and monomer component is an extremely important factor as it not only affects the workability of dentists, technicians, etc., but also greatly affects the long-term use of dentures. In particular, the outermost layer of dental crown materials for veneers or jacket crowns not only protects the inner layer, but also undergoes significant surface changes due to abrasion from toothbrushes, etc., so surface stability is extremely important in terms of appearance. fulfill a role. However, although conventional veneers or jacket crowns have been technologically advanced, they cannot completely prevent the water absorption of the crown material, cannot remove stains, and have particularly poor wear resistance. Due to the insufficient amount, it was not possible to prevent wear caused by toothbrushes. That is, the greatest technical challenge has been to develop a resin that has excellent abrasion resistance and does not absorb water for either the veneer crown or the jacket crown. The present inventors have been earnestly trying to develop a new dental crown material that compensates for the drawbacks of the above-mentioned dental crown materials, and have already proposed several methods. One is the general formula

[Formula] (where R is a saturated aliphatic hydrocarbon residue, R' is an unsaturated aliphatic hydrocarbon residue, and n is a positive number from 1 to 3) It is a powdered resin consisting of a polymer of epoxysuccinic acid unsaturated ester or a tartaric acid unsaturated ester polymer. The veneer crowns and jacket crowns made using these resins for dental crowns have low water absorption and are particularly excellent in wear resistance, and can be said to be groundbreaking powdered resins for dental crowns. However, with these resins for dental crowns, depending on the type of liquid or paste monomer component used when molding the veneer crown or jacket crown, the molded veneer crown or jacket crown may become cloudy and opaque. Therefore, it has been found that defects may occur if the color tone differs before and after molding. Polymethyl methacrylate (hereinafter referred to as
(abbreviated as PMMA), the polymerized product exhibits transparency regardless of the type of monomer component.
Color matching is easy. This is because PMMA swells with the monomer, as mentioned above.

This is because the unsaturated carbonate polymer, epoxysuccinic acid unsaturated ester polymer, or tartaric acid unsaturated ester polymer represented by the formula is a crosslinkable polymer, so it does not swell with the monomer liquid. It is estimated that The present inventors have developed crosslinked polymers that have excellent properties in terms of abrasion resistance and water absorption, such as

We are conducting intensive research to solve the above-mentioned drawbacks when using crosslinkable polymers such as unsaturated carbonate polymers, epoxysuccinic acid unsaturated ester polymers, tartaric acid unsaturated ester polymers, etc. represented by the formula I came.
As a result, when polymerizing a mixture of a crosslinkable polymer and a liquid monomer or a paste monomer component, the refractive index of the crosslinkable polymer and the refractive index of the monomer polymer can be matched as much as possible. In particular, the present invention was completed based on the discovery that the resulting polymerized form exhibits transparency. That is, the present invention provides the formula

[Formula] (R is a saturated aliphatic hydrocarbon residue, R is an unsaturated aliphatic hydrocarbon residue, and n is a positive number from 1 to 3) Crosslinkable polymers selected from homopolymers of saturated esters or unsaturated tartaric esters and copolymers between these monomers or with monomers selected from other unsaturated carboxylic esters and methacrylate derivatives. A glycol dimethacrylate monomer and/or a dimethacrylate phenylpropane monomer is added in the presence of a dimethacrylate monomer such that the difference between the refractive index of the crosslinkable polymer and the refractive index of the polymer obtained by polymerizing the monomer is
This is a method for producing a dental crown material, characterized in that the polymerization is selectively carried out so that the polymerization content is 0.01 or less. As described above, when a polymerizable monomer is polymerized in the presence of PMMA, a transparent dental crown material can be obtained regardless of the type of the monomer. However,
In the present invention, the use of a powder crosslinkable polymer and a liquid or paste polymerizable monomer in combination within a specified refractive index range is advantageous in order to polymerize and obtain a transparent dental crown material. extremely important. In general, for the refractive index of crosslinked polymers,
The difference from the refractive index of the polymer is within ±0.01, especially ±
It is preferable to use a combination of polymerizable monomers such that the ratio is within 0.003. The monomer component may be used alone, or two or more components may be mixed to adjust the refractive index with respect to the crosslinkable polymer. Since the polymerizable monomer used in the present invention is limited by the refractive index of the polymer, the following known monomers are generally suitably used. For example, glycol dimethacrylate monomers such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, and tetraethylene glycol dimethacrylate, 2,2-bis[4-methacryloxyphenyl)propane, 2,2bis[4 −
Diacrylate phenylpropane monomers such as (2-methacryloxyethoxy)phenyl]propane and 2,2bis[4-(2-methacryloxypolyethoxy)phenyl]propane are representative examples that are preferably used. Most commonly, these polymers are used alone or in a mixture to match the refractive index of the polymer. On the other hand, crosslinkable polymers are also not particularly limited, but
For example, as a dental crown resin, the general formula as mentioned above is used.

Crosslinkable polymers such as unsaturated carbonate polymers, epoxysuccinic acid unsaturated ester polymers, and tartaric acid unsaturated ester polymers represented by the formula are preferably used. Note that the crosslinkable polymer has only a fixed refractive index when it is a homopolymer, but it may be made into a copolymer in order to obtain a crosslinkable polymer having an arbitrary refractive index. That is, by using comonomers with different refractive indexes, a crosslinkable polymer having a desired refractive index can be obtained. Such comonomers are not particularly limited as long as they can be copolymerized, and in consideration of the refractive index of the polymer, the unsaturated carbonate polymer, the epoxysuccinic acid unsaturated ester polymer, and the tartaric acid unsaturated ester polymer can be used. Each monomer may be selected from monomers that can be copolymerized with these monomers. Typical copolymerizable monomers that are generally preferably used include unsaturated carboxylic esters other than the unsaturated carboxylic esters that give the above-mentioned polymers, such as diallyl phthalate, isoallyl phthalate, and tearyl phthalate. , allyl cinnamate, allyl benzoate, etc. are preferably used, and bisphenol A dimethacrylate, 2,2-bis(4-methacryloxyethoxyphenyl)propane, 2,2-bis(4-methacryloxypolyethoxy) phenyl) propane,
Methacrylate derivatives such as phenyl methacrylate and β-phenylethyl methacrylate are preferably used. Further, the proportion of the copolymerizable comonomer as described above may be determined in accordance with the desired refractive index of the resulting crosslinkable polymer copolymer. A method for obtaining a crosslinkable polymer is to use the monomer that imparts crosslinking alone or in a mixture with other copolymerizable monomers in the presence of a radical initiator at room temperature to
A method of polymerizing by heating is preferred. The radical initiator is not particularly limited, and known radical initiators can be used.
Typical radical polymerization initiators that are generally suitably used include benzoyl peroxide, diisopropyl peroxycarbonate, di-n-propyl peroxydicarbonate, di-secandabutyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, These are peroxides such as acetyl peroxide and diethyl peroxide, or azo compounds such as azobisisobutyronitrile. The amount of the radical polymerization initiator to be used varies depending on the polymerization type, polymerization conditions, type of monomer, etc. and cannot be absolutely limited, but it is generally most preferably used in the range of 0.1 to 10% by weight based on the monomer. The crosslinkable polymer used in the present invention is generally used alone or in combination with other polymers such as methacrylate non-crosslinkable polymers, and is generally used in combination with these powdered resins and liquid or paste polymerizable polymers. It is kneaded with a monomer to make a dental crown material. Therefore, the crosslinkable polymer is generally used in powder form. The degree of powderiness is not particularly limited and may be pulverized if necessary, but in general, those having an average particle size of 1 to 350μ are most widely used.
The technique for turning the crosslinkable polymer into powder is not particularly limited, and when producing the crosslinkable polymer, it can be obtained as a powder, or the crosslinkable polymer can be crushed using a suitable grinder. It is sufficient to grind it to a particle size. In addition, as described above, when using a mixture of a crosslinkable polymer and another non-crosslinkable polymer, the crosslinkable polymer is contained in an amount of 10% (by weight) or more, preferably 50% (by weight) or more. It is preferred to use The above-mentioned mixture of the crosslinkable polymer and the non-crosslinkable polymer is preferably not only a simple blend but also a form in which a thin layer of the non-crosslinkable polymer is formed on the surface of the crosslinkable polymer powder. used. The above-mentioned non-crosslinkable polymer is not particularly limited, and those generally known as powdered resins for dental crowns can be used, since they do not have any adverse effect on the transparency of the dental crown material, as described above. A method for selecting a polymerizable monomer for a typical crosslinkable polymer in the present invention will be explained in more detail below. (1) Poly-diethylene glycol bis(allyl carbonate) (hereinafter referred to as
When using PBAC (abbreviated as PBAC), the refractive index of this crosslinkable polymer is η _D = 1.496, so the refractive index of the polymer obtained by polymerizing the polymerizable monomer is 1.486~1.506
You need to choose one within the range. Examples of polymerizable monomers that provide the refractive index include diethylene glycol dimethacrylate (hereinafter abbreviated as DEDMA) and 2,2-bis(4-methacryloxypolyethoxyphenyl)propane (hereinafter abbreviated as DEDMA).
BMPEPP (abbreviated as BMPEPP)
They may be used in a mixture such that the content thereof is 10wt% or less. (2) Polyepoxysuccinic acid diallyl ester (hereinafter abbreviated as PESADA) as a crosslinkable polymer
or polytartrate diallyl ester (hereinafter
When using PTADA), the refractive index of both of these crosslinkable polymers is η _D =1.510, so the polymer obtained by polymerizing the polymerizable monomer has a refractive index of 1.500 to 1.500.
Limited to those with a refractive index of 1.520. Examples of polymerizable monomers that provide a refractive index in this range include
When a mixture of DEDMA and BMPEPP is used as a liquid monomer, the content of BMPEPP is 30wt%.
What is necessary is just to mix and use so that it may become the following mixture. (3) As a crosslinkable polymer, diethylene glycol bis(allyl carbonate) (hereinafter abbreviated as BAC), diallyl phthalate (hereinafter abbreviated as DAP) or diallyl isophthalate (hereinafter abbreviated as DAP) is used.
When using a copolymer with DAP (abbreviated as DAIP), the refractive index of the copolymer changes depending on the content of DAP or DAIP in the copolymer. As a result, the polymerizable monomer used changes. For example, when using a mixture of DEDMA and BMPEPP as a polymerizable monomer, the combination of the copolymerization composition of the crosslinkable polymer and the composition of the polymerizable monomer mixture can be selected as shown in Table 1. .

[Table] (4) ESADA or TADA as a crosslinkable polymer
When using a copolymer with DAP or DAIP, (3)
Similarly, the combinations shown in Table 2 can be selected.

[Table] As mentioned above, and as is clear from the examples described later, the dental crown material of the present invention has extremely excellent wear resistance, good water resistance, extremely good compressive strength, and excellent transparency. show. Therefore, when the dental crown material of the present invention is used for a veneer crown or a jacket crown, no scratches remain on the surface even after an abrasion test, the surface condition is good, and it is significantly more durable than conventional products. , stable over the long term. Moreover, since it exhibits transparency, it is easy to match the color tone. Therefore, when used in the enamel layer, it exhibits transparency and depth of color, making it possible to create veneers or jacket crowns that closely resemble natural teeth in appearance. EXAMPLES In order to explain the present invention more specifically, Examples and Comparative Examples will be described below, but the present invention is not limited to these Examples. The physical properties of the veneer of the present invention in the Examples are the results of the following tests conducted on the powdered resin forming the enamel layer, liquid monomer, and additives kneaded in accordance with the Examples. 1. Hardness Test Brinell hardness was measured using a micro Brinell hardness meter at a load of 25 kg and a loading time of 30 seconds. 2 Water Absorption Test After the sample was made to a constant weight, it was immersed in distilled water at 37°C for 7 days, and the weight increase due to water absorption was reduced by the surface area to determine the water absorption amount. 3. Abrasion test A toothbrush type abrasion tester was used to conduct a test piece that had absorbed water. Wear conditions are load at 23℃
300g, wear distance 4500m (20cm x 22500 times),
The amount of wear was divided by the specific gravity and expressed as the wear depth. As an anti-friction material, White Lion toothpaste,
The toothbrush was made of spring tryon (made of nylon). 4 Compression Test The compressive strength of the dry test piece was measured using a universal testing machine. 5. Light transmittance The transmittance at a wavelength of 600 mm was measured and defined as transparency. Furthermore, the abbreviations used in the Examples and Comparative Examples are as follows, excluding those already defined. MMA: Methyl methacrylate PMMA: Polymer of MMA BPO: Benzoyl peroxide ESADA: Diallyl epoxysuccinate TADA: Diallyl tartrate CAA: Allyl cinnamate Example 1 and Comparative Examples 1 to 4 Crosslinkable polymer powder Average particle size 40μ as a component
After thoroughly kneading the PBAC (refractive index η _D 1.496) with the monomer liquid components shown in Table 1 at a weight ratio of 1.4:1 (including 1% by weight of BPO), 10 mm x 10 mm x 3 mm
(thickness) and heated at 130°C for 15 minutes at an air pressure of 5 kg/cm ² to polymerize and form samples for measuring the physical properties of veneers.
The results are shown in Table 1 together with Comparative Examples 1 to 4.
However, in Comparative Example 4, the powder component had an average particle size of 40μ.
This is an example using PMMA powder (refractive index η _D =1.485).

[Table] Example 2 and Comparative Examples 5 to 6 Average particle size of 40μ as powder component of crosslinkable polymer
PESADA (refractive index 1.510) or PTADA (refractive index
1.510), and the monomer liquid shown in Table 2 was used, and the other procedures were the same as in Example 1. The results are shown in Table 2 together with Comparative Examples 5 and 6.

[Table] Example 3 and Comparative Examples 7 to 9 A mixture of 60% BMPEPP and 40% DEDMA was used as the monomer liquid (the refractive index when this monomer liquid was polymerized was η _D =1.536), and the powder component of the crosslinkable polymer was The experiment was carried out in the same manner as in Example 1, except that the BAC copolymer powder shown in Table 3 (average particle size 20 to 50 μm) was used. The results are shown in Table 3 together with Comparative Examples 7 to 9.

【table】

[Table] Example 4 and Comparative Example 10 The same monomer liquid as in Example 3 was used, and the powder components of the crosslinkable polymer were shown in Table 4.
Each copolymer of ESADA or TADA (average particle size 20~
50μ) in the same manner as in Example 1. The results are shown in Table 4 together with Comparative Example 10.

[Table] Example 5 Using the same monomer liquid as in Example 3,
BAC60wt% as a powder component of crosslinkable polymer
A powder (refractive index η _D 1.526) with an average particle size of 33 μ of a copolymer with 40 wt% DAP was mixed with 80 wt% and an average particle size of 40 μ
Example 1 using a mixture with 20wt% PMMA powder
Samples were prepared in the same manner as above, and their physical properties were measured. Sample light transmittance 10.2%, hardness H _B 17.2, water absorption 1.33mg/cm ² , wear depth 6.2×10 ^-3 , compressive strength 1230
Kg/cm ² and showed good transparency and physical properties. Example 6 Using the same monomer liquid as in Example 3,
Powdered BAC as a powder component of crosslinkable polymers
Copolymer of and DAP (BAC/DAP=60/40wt ratio)
A sample was prepared in the same manner as in Example 1, and its physical properties were measured, except that 100 parts of the powder was kneaded with 20 parts of MMA and polymerized by heating under pressure at 80° C. for 20 minutes. As a result, the optical transparency was 10.2%, the hardness H _B was 17.8, the water absorption was 1.28 mg/cm ² , the wear depth was 4.7×10 ^-3 cm, and the compressive strength was
1140Kg/cm ² , indicating good transparency and physical properties. Example 7 Using the same monomer liquid as in Example 3,
BAC60wt% as a powder component of crosslinkable polymer
A powdered copolymer containing 40 wt% DAP (average particle size 33μ) was first pretreated with a monomer solution of 20 parts per 100 parts of the powder component in the same manner as in Example 6, and then a sample was prepared in the same manner as in Example 1. As a result of measuring the physical properties, the light transmittance was 12.5%, the hardness H _B was 17.5, the water absorption was 1.37 mg/cm ² ,
The abrasion depth was 3.1×10 ^-3 cm, the compressive strength was 950 Kg/cm ² , and the material had good transparency and physical properties.

Claims (1)

[Claims] 1 Represented by the formula [Formula] (R is a saturated aliphatic hydrocarbon residue, R' is an unsaturated aliphatic hydrocarbon residue, and n is a positive number from 1 to 3) homopolymers of unsaturated carbonates, epoxysuccinic acid unsaturated esters or tartaric acid unsaturated esters, and copolymers between these monomers or with monomers selected from other carboxylic acid unsaturated esters and methacrylate derivatives. In the presence of a crosslinkable polymer selected from the combination, a glycol dimethacrylate monomer and/or a dimethacrylate phenylpropane monomer is obtained by polymerizing the refractive index of the crosslinkable polymer and the monomer. The difference between the refractive index of the polymer and
1. A method for producing a dental crown material, which comprises selectively polymerizing the material so that it is 0.01 or less.