JPH04261110A - Composition for dental use - Google Patents

Abstract

PURPOSE:To shorten the curing time of a cold-setting dental composition and to suppress the heat-generation in curing. CONSTITUTION:The objective dental composition is composed of a liquid agent composed mainly of a methacrylic acid ester and a powder agent composed mainly of a methacrylic acid ester polymer and/or copolymer and is polymerizable and curable at ordinary temperature by the mixing of the liquid agent and the powder agent. In the above composition, the liquid agent contains 5-50wt.% of trimethylolpropane trimethacrylate and 2-30wt.% of 2-hydroxyethyl methacrylate.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a room-temperature curing dental composition used for the production of temporary crowns, personal trays, denture bases, etc., and for the repair and relining of dentures.

0002

[Prior Art] Methacrylate resins are chemically stable even in the special and harsh environment of the oral cavity.
It has been widely used as a dental resin because it has low toxicity to the human body, excellent transparency, and is easy to color. In addition, when using this material, a powder-liquid polymerization method unique to dentistry is used, in which a powder agent whose main component is a powdered methacrylate polymer and a liquid agent whose main component is methacrylate are mixed, and the mixture is heated or left at room temperature. A method of polymerizing and curing is generally used. For example, in the production of denture bases, powder and liquid are mixed,
Once the material has reached a moderately plastic state (rice cake-like state), it is inserted into a plaster mold, and then pressurized and heated.

[0003] On the other hand, when producing a temporary crown or lining a denture using a direct method, it is necessary to harden the crown in the patient's mouth, and therefore a polymerization method using heat cannot be used. Furthermore, when repairing a damaged denture base, the heat curing method is difficult to employ because heating causes deformation of the denture base.

[0004] Therefore, in such cases, a material that hardens at room temperature is generally used. In this type of material, a small amount of tertiary amine, which is a radical polymerization promoter, is added to the liquid agent, so that polymerization is initiated by a redox reaction when the powder and liquid are mixed. In this case, it becomes possible to cure the resin even at room temperature.

[0005]

[Problem to be Solved by the Invention] When using the above-mentioned room-temperature curing material, the curing reaction is significantly suppressed as the temperature decreases, so the curing time becomes significantly longer in the winter when the temperature is low, resulting in a reduction in work efficiency. becomes extremely bad. On the other hand, in the summer when temperatures are high, although the curing time itself is considerably shorter, the problem arises that the heat generated during curing increases significantly.
Particularly when it is necessary to harden the material in the oral cavity, there is a problem that problems such as burns may occur to the patient.

[0006] The curing time can be shortened to some extent by increasing the amount of tertiary amine added to the liquid agent and the organic peroxide added to the powder agent, but this method also has its limitations. That is, tertiary amine itself is extremely toxic, and addition of a large amount is not preferable from the viewpoint of safety. Furthermore, tertiary amines cause yellowing of the cured product and significantly impair aesthetics, so addition of large amounts must be avoided. Furthermore, when the amount of tertiary amine added is about 1% by weight, the curing time effectively shortens as the amount added increases, but beyond that, the effect of increasing the amount added becomes very small, and if the amount of tertiary amine added is If you try to shorten the time, you will have to add quite a large amount of several percent. For these reasons, the amount of tertiary amine added is generally limited to about 1% by weight.

Furthermore, since the organic peroxide remains in the cured product even after the curing reaction is completed and gradually dissolves out in the oral cavity, it is not preferable to add a large amount of the organic peroxide. In this case as well, the effect of increasing the amount added is significant up to about 1% by weight, but beyond that the effect becomes extremely small, and if you want to significantly shorten the curing time, you will need to add a considerably larger amount. I will have to. For these reasons, the amount of organic peroxide is also generally limited to about 1% by weight.

[0008] If we ignore the problems associated with increasing the amount of tertiary amines and organic peroxides and try to shorten the curing time by adding large amounts of these, it is true that the curing time will be shortened. Although the time can be significantly shortened, the heat generated during curing becomes abnormally high, which not only poses problems in handling such as the risk of burns, but also causes problems such as the monomer components boiling due to high temperatures and bubbles forming in the cured product. There is a point.

[0009] The present invention takes into account the above points and aims to provide a room temperature curing dental composition that generates less heat during curing and has a short curing time.

0010

[Means for Solving the Problems] In order to solve the above problems, the dental composition of the present invention comprises a liquid agent containing a methacrylic acid ester as a main component, and a methacrylic acid ester polymer, copolymer, or polymer. In a dental composition consisting of a powder mainly composed of a copolymer, which polymerizes and hardens at room temperature by mixing a liquid and a powder, 5 to 50% by weight of trimethylolpropane trimethacrylate is added to the solution.
, 2-hydroxyethyl methacrylate in an amount of 2 to 30% by weight.

[0011]

[Function] The dental composition of the present invention constituted as described above contains 5 to 50% by weight of trimethylolpropane trimethacrylate and 2 to 30% by weight of 2-hydroxyethyl methacrylate in a liquid agent containing methacrylic acid ester as a main component. By weight% content, the curing time can be significantly shortened even with the amount of tertiary amine and organic peroxide used in the past, and the heat generation during curing is comparable to that of conventional room temperature curing types. It can be kept considerably lower than the material.

0012

[Example] An example will be explained. Consists of a liquid agent mainly composed of methacrylic acid ester and a powder agent mainly composed of methacrylic acid ester polymer or copolymer or polymer and copolymer. By mixing the liquid agent and powder agent, polymerization and curing occur at room temperature. In the dental composition containing 5 to 50% of trimethylolpropane trimethacrylate in the solution,
2-3% by weight of 2-hydroxyethyl methacrylate
It is characterized by containing 0% by weight.

The amount of trimethylolpropane trimethacrylate used here is 5 to 50% by weight in the liquid preparation.
In particular, it is preferably contained in an amount of 10 to 30% by weight. The reason why the amount added is limited to 5 to 50% by weight is that if it is less than 5% by weight, the effect of suppressing heat generation during curing cannot be obtained sufficiently, and if it exceeds 50% by weight, the effect of suppressing heat generation will not be obtained. This is because, although the effect is greater, the crosslinking density of the cured product becomes too high, resulting in a problem of physical brittleness.

The amount of 2-hydroxyethyl methacrylate added is preferably 2 to 30% by weight, particularly 5 to 20% by weight. The reason why the amount of 2-hydroxyethyl methacrylate added is limited to 2 to 30% by weight is that if it is less than 2% by weight, the effect of shortening the curing time cannot be sufficiently obtained, and if it is more than 30% by weight, This is because although the curing time is extremely short, the heat generated during curing becomes extremely high, making it impractical. Furthermore, if too much 2-hydroxyethyl methacrylate is added, the number of hydrophilic OH groups in the molecules of the cured product will increase, and the water absorption of the material will increase, resulting in new problems such as discoloration in the oral cavity and easy staining.

There are various methacrylic acid esters that can be used in the present invention, including methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, ethylhexyl methacrylate, lauryl methacrylate, and the like. These may be used alone or in combination of two or more.

The tertiary amine used in the present invention includes:
N. N'-dimethylaniline, N. N'-diethylaniline, N. N'-diethyl-P-toluidine, N. N'-
Dimethyl-P-toluidine, tolyldiethanolamine, etc. are included, and these may be used alone or in combination of two or more. The amount of these additives varies depending on the desired curing speed and the composition of the liquid and powder used, but when using the material of the present invention, a practical range of 0.5 to 1.5 parts by weight per 100 parts by weight of the liquid component is used. Curing speed is obtained.

On the other hand, methacrylate polymers or copolymers that can be used in the powder of the present invention include homopolymers such as polymethyl methacrylate and polyethyl methacrylate, methyl methacrylate/ethyl methacrylate copolymers, and methyl methacrylate/n-butyl. Copolymers such as methacrylate copolymers are included. These may be used in various molecular weights and particle sizes depending on the purpose, and may be used alone or in combination of two or more.

Organic peroxides that can be used in powders include diacyl peroxides such as benzoyl peroxide and lauroyl peroxide, among which benzoyl peroxide is most preferred. When this benzoyl peroxide is used, a practical curing rate can be obtained in the range of 0.5 to 1.5 parts by weight per 100 parts by weight of the powder.

Depending on the purpose of use, the powder may contain various pigments such as red iron oxide and titanium dioxide, and short fibers such as nylon and rayon.

When using the material of the present invention, there are several methods: pouring a mixture of powder and liquid into a mold, press-molding the mixture and plasticizing it, and applying the powder to the tip of a brush soaked with the liquid. Various methods can be used, such as the so-called brush stacking method, in which the formed spherical powder-liquid mixture is filled or applied to a predetermined location.

(Experimental Example) An experimental example of the present invention is as follows. 70 parts by weight of methyl methacrylate, 20 parts by weight of trimethylolpropane trimethacrylate, 10 parts by weight of 2-hydroxyethyl methacrylate, N. A solution was prepared by mixing 1 part by weight of N'-dimethyl-P-toluidine.

Methyl methacrylate/ethyl methacrylate copolymer (with an average molecular weight of 250,000 and an average particle diameter of 50 μm)
Methyl methacrylate/ethyl methacrylate = 3/2
Weight ratio) 80 parts by weight, average molecular weight 600,000, average particle size 7
20 parts by weight of 0μ polyethyl methacrylate and 1 part by weight of benzoyl peroxide were mixed in a ball mill for 1 hour to prepare a powder.

2 g of powder and 1 g of liquid were placed in a polypropylene cup with an inner diameter of 30 mm, stirred and mixed for 10 seconds, and then allowed to stand. The tip of a thermocouple was inserted into the center of the mixture to measure the internal temperature, and the curing time was determined by measuring the time from the start of mixing until reaching the maximum temperature. Such measurements were carried out under various conditions at room temperature of 18°C to 28°C.

Comparative Example (1) 100 parts by weight of methyl methacrylate, N.I. A solution was prepared by mixing 1 part by weight of N'-dimethyl-P-toluidine. Using this liquid agent and the powder agent shown in the experimental example, the curing time and exothermic peak temperature were measured in the same manner as in the experimental example.

Comparative Example (2) 100 parts by weight of methyl methacrylate, N.I. A solution was prepared by mixing 3 parts by weight of N'-dimethyl-P-toluidine.

The same polymer component 1 as shown in the experimental example
3 parts by weight of benzoyl peroxide was added to 00 parts by weight and mixed in a ball mill for 1 hour to prepare a powder. Using these liquids and powders, the curing time and exothermic peak temperature were measured using the same method as shown in the experimental example.

Comparative Example (3) 80 parts by weight of methyl methacrylate, 20 parts by weight of trimethylolpropane trimethacrylate, N.I. 1 part by weight of N'-dimethyl-P-toluidine was mixed to prepare a solution. Using this liquid agent and the powder agent shown in the experimental example, the curing time and exothermic peak temperature were measured in the same manner as shown in the experimental example. Note that this test was carried out only when the room temperature was 24°C.

Comparative Example (4) 90 parts by weight of methyl methacrylate, 10 parts by weight of 2-hydroxyethyl methacrylate, N.I. N'-dimethyl-P
1 part by weight of toluidine was mixed to prepare a liquid preparation. Using this liquid agent and the powder agent shown in the experimental example, the curing time and exothermic peak temperature were measured in the same manner as in the experimental example. In addition, here too, the room temperature is 24
This was done only when the temperature was ℃.

The results of the experimental examples and comparative examples are shown in Table 1 and FIGS. 1 and 2.

[0030]

[Table 1]

As is clear from these, N. Even when the amount of N'-dimethyl-P-toluidine is the same, the curing time can be significantly shortened by incorporating both components, trimethylolpropane trimethacrylate and 2-hydroxyethyl methacrylate, into the solution. This makes it possible to work efficiently even at low temperatures.

As is clear from Comparative Example (2), this shortening of the curing time is due to the N. This can be achieved by significantly increasing the amount of N'-dimethyl-P-toluidine and the amount of benzoyl peroxide in the powder, but in that case, as shown in Figure 2, the exothermic peak temperature becomes extremely high, which poses a practical problem. . In this case, highly toxic N. Since a fairly large amount of N'-dimethyl-P-toluidine is added, the safety of the material itself becomes a problem. Furthermore, since the cured product yellows significantly over time, it also poses a problem from an aesthetic point of view. Furthermore, since the amount of benzoyl peroxide in the powder is quite large, this also causes problems such as elution during use.

On the other hand, the material shown in the experimental example was N. Since both N'-dimethyl-P-toluidine and benzoyl peroxide are kept at low levels as before, the above-mentioned problems cannot occur.

The material of the present invention exhibits its effects only when two components, trimethylolpropane trimethacrylate and 2-hydroxyethyl methacrylate, are added to the liquid, and it is not sufficient to use just one of these components. You won't get the results you want. For example, Comparative Example (3) contains only trimethylolpropane trimethacrylate, but in this case, although the curing time is slightly shorter than in Comparative Example (1), a sufficient effect cannot be obtained. However, as is clear from the comparison of the exothermic peak temperatures when the curing times are approximately the same, the heat generation during curing can be suppressed to a low level by blending trimethylolpropane trimethacrylate. Further, Comparative Example (4) is one in which only 2-hydroxyethyl methacrylate is added, but in this case, although the curing time is considerably shorter than that of Comparative Example (1), no heat generation suppressing effect is observed.

On the other hand, in the case of an experimental example in which both trimethylolpropane trimethacrylate and 2-hydroxyethyl methacrylate were blended, the curing time was even shorter than in the case of a material in which only 2-hydroxyethyl methacrylate was added, and the heat generation was kept low. It exhibits extremely unique properties that are completely absent from conventional materials.

[0036] Although the method of adding trimethylolpropane trimethacrylate or 2-hydroxyethyl methacrylate to other methacrylic acid esters and copolymerizing them has been carried out in the past, the purpose thereof is fundamentally different from that of the present invention. They are completely different. That is, trimethylolpropane trimethacrylate is added as a crosslinking agent and is intended to improve the mechanical strength of the material. The amount added is generally very small, a few percent. In the case of 2-hydroxyethyl methacrylate, it is added to improve the biocompatibility of the cured product by taking advantage of the fact that it has a hydrophilic OH group in its molecule. In this case as well, the amount added is suppressed to about several percent.

In the present invention, trimethylolpropane trimethacrylate and 2-hydroxyethyl methacrylate are used for purposes completely different from conventional ones, such as shortening curing time and suppressing heat generation during curing. It is characterized by the combination of these two components for this purpose. Furthermore, the purpose of the present invention can only be achieved by blending these two components within a specific range, and satisfactory results cannot be obtained with only one component.

For example, since trimethylolpropane trimethacrylate slowly copolymerizes with methacrylic acid ester, the heat generation during curing can be suppressed considerably by adding it, but the effect of shortening the curing time is not so great. It cannot be shortened sufficiently. Furthermore, when methacrylic acid ester is blended with 2-hydroxyethyl methacrylate and copolymerized, the curing speed increases significantly;
The heat generated during curing also becomes very large, which poses a practical problem.

On the other hand, according to the present invention, trimethylolpropane trimethacrylate and 2-
By containing hydroxyethyl methacrylate within a predetermined range in the liquid agent and copolymerizing it, the curing time can be significantly shortened even with the amount of catalyst used conventionally.
Moreover, the ideal property is that the heat generated during curing can be suppressed to a much lower level than in the past.

[0040]

[Effects of the Invention] Since the present invention is constructed as described above, it achieves the effects described below.

[0041] It consists of a liquid agent whose main component is a methacrylic ester and a powder agent whose main components are a methacrylic ester polymer or copolymer, or a polymer and a copolymer. polymerization. In a dental composition that hardens, the hardening time can be significantly shortened by containing 5 to 50% by weight of trimethylolpropane trimethacrylate and 2 to 30% by weight of 2-hydroxyethyl methacrylate in the liquid agent. Furthermore, heat generation during curing can be suppressed considerably lower than that of conventional room-temperature curing materials.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between room temperature and curing time.

FIG. 2 is a diagram showing the relationship between curing time and exothermic peak temperature.

Claims (1)

[Claims] Claim 1: Consists of a liquid agent containing a methacrylic acid ester as a main component, and a powder agent containing a methacrylic acid ester polymer or copolymer, or a polymer and a copolymer as a main component,
In a dental composition that polymerizes and hardens at room temperature by mixing the liquid and powder, 5 to 50% by weight of trimethylolpropane trimethacrylate is added to the liquid.
- A dental composition containing 2 to 30% by weight of hydroxyethyl methacrylate.