JP2981207B1 - Denture base artificial tooth occlusal surface reconstruction composition and polymerization method thereof - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To make polymerization sufficient, to set curing time arbitrarily, and to reduce deformation. SOLUTION: In a composition in which a photopolymerization initiator is blended with at least one of a liquid agent composed of a radically polymerizable methacrylate and a radical polymerization accelerator and a powdery agent composed of a methacrylate polymer or a copolymer and a radical polymerization initiator, After the mixture of the powder and the liquid is polymerized and cured at room temperature, the mixture is irradiated with visible light to cause a photopolymerization reaction, thereby increasing the degree of polymerization.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a denture base artificial tooth occlusal surface in which the degree of polymerization of a room temperature polymerization type composition used for reconstructing an artificial denture base occlusal surface is improved and the surface hardness is improved. The present invention relates to a restructuring composition and a polymerization method thereof.

[0002]

[Problems to be solved by the prior art]

(Heat polymerization method) Conventionally, as a polymerization type dental composition, a so-called heat polymerization type, in which a polymerization reaction is initiated and cured by heating, is generally used, and these are still widely used for denture base resins and the like even today. Have been. Although this method has the advantage of increasing the degree of polymerization of the cured product, the operation is extremely complicated.

(Normal Temperature Polymerization Method) Subsequently, a room temperature polymerization type composition using a redox catalyst was developed, and the easiness of polymerization without heating was received. Widely used.

Although this room temperature polymerization type composition has an advantage that heating is not required, it has a drawback that the physical properties of a cured product are inferior because a sufficient degree of polymerization cannot be obtained.
Particularly, since the material surface is strongly inhibited by polymerization in the atmosphere due to oxygen in the atmosphere, there is a problem that the polymerization is insufficient and the surface hardness is significantly reduced.

[0005] This is a major drawback in applications requiring high surface hardness and excellent wear resistance, such as reconstruction of an occlusal surface of a denture base artificial tooth.

(Photopolymerization Method) On the other hand, a photopolymerization method of irradiating visible light has been developed as another method of polymerization. This method has been developed for the purpose of improving the operability of a room temperature polymerization type composite resin for filling.

[0007] That is, initially, as a filling composite resin, a room temperature polymerization type in which a component containing a polymerization initiator and a component containing a polymerization accelerator are mixed at the time of use and a polymerization reaction is caused by a redox catalyst system is mainly used. there were. Although this method has become widespread because no special equipment is required, it has been pointed out that the operation time is limited by the curing time.

[0008] That is, all operations such as filling must be completed within the curing time, otherwise, there is a problem that the material is cured during the operation. In order to obtain excellent physical properties, the curing speed had to be set earlier to some extent, which further shortened the operation time and made the operability worse.

To solve such a problem, the above-mentioned photopolymerization method has been adopted. According to this method, the polymerization reaction does not start until light irradiation, so that the operator can spend a sufficient time for the filling operation.

[0010] However, although the photopolymerization method has advantages in terms of operability, there is no particular advantage in other respects, and conversely, several disadvantages are pointed out as follows. Since polymerization is inhibited by oxygen in the atmosphere, polymerization on the surface becomes insufficient. Since polymerization occurs from the surface, deformation occurs during curing. In the case of a thick wall, the internal curing is insufficient. Curing does not occur in the areas not exposed to light. The degree of polymerization is greatly affected by the light intensity of the light irradiator used.

As described above, the conventional photopolymerization method is mainly intended to improve operability, and is not intended to increase the degree of polymerization and improve the physical properties of the material.

The photopolymerization method has recently been partially applied to powder-liquid mixture type materials, and photopolymerization type denture base repair materials and the like have been developed. However, this material is introduced from the viewpoint of improving operability by not being restricted by the operation time, and does not consider any merits such as improvement in surface hardness. Therefore, it contains all the above-mentioned disadvantages peculiar to photopolymerization.

[0013] The above disadvantages are all undesirable, but among them, the inhibition of surface polymerization and the lowering of surface hardness means that the denture base artificial tooth occlusion which requires high hardness and excellent wear resistance is required. Reconstructing the surface is a fatal drawback.

[0014]

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention relates to a powder-liquid mixed room temperature polymerization composition, in which a photopolymerization initiator is blended with at least one of a powder or a liquid, and In addition, photopolymerizability is also provided, and after the powder-liquid mixture is polymerized at room temperature, photopolymerization reaction is caused by irradiating light, and the surface hardness of the material is improved by increasing the degree of polymerization. And a method for reconstructing an occlusal surface of a denture base artificial tooth.

The combined use of room temperature polymerization and photopolymerization of the present invention has the advantage that the degree of polymerization can be greatly increased by photopolymerization after room temperature polymerization, but also has the following advantages. The curing time at room temperature can be set arbitrarily. At a minimum, polymerization by room temperature polymerization is guaranteed. Surface polymerization is not inhibited. Even in the case of thick wall, there is no fear of poor internal curing. Uncured portions do not become uncured. Deformation due to photopolymerization is very small.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a room-temperature polymerization type comprising a liquid material comprising a radically polymerizable methacrylate and a radical polymerization accelerator, and a powder comprising a methacrylate polymer or copolymer and a radical polymerization initiator. In the composition, a photopolymerization initiator is blended with at least one of the powder and the liquid, and a photopolymerization reaction is caused by irradiating visible light after the powder and liquid mixture is polymerized at room temperature to increase the degree of polymerization. A denture base artificial tooth occlusal surface reconstructing composition characterized by further improving the surface hardness of a cured product, and a polymerization method thereof.

According to the present invention, it is possible to greatly improve the problems of the conventional room-temperature polymerization type denture base artificial tooth occlusal surface reconstruction composition.

That is, in the conventional room temperature polymerization type denture base artificial tooth occlusal surface reconstructing composition, it is necessary to set the curing speed earlier in order to obtain a high degree of polymerization, which is a problem in terms of operation time. On the other hand, if the curing time is set to a long time in order to secure a sufficient operation time, a sufficient degree of polymerization cannot be obtained, and the surface hardness of the cured product becomes extremely low.

In particular, the surface of a material is strongly inhibited by polymerization in the atmosphere due to oxygen in the atmosphere, so that the surface hardness is extremely low. In the case of the room-temperature polymerization type composition, the polymerization reaction proceeds with time even after curing and gradually hardens, but this also has a limit, and a high degree of polymerization cannot be obtained.

In the present invention, however, the degree of polymerization is significantly increased by first performing normal temperature polymerization and then irradiating visible light to carry out photopolymerization, so that the surface hardness of the material is significantly increased. In addition, in this case, polymerization is hardly affected by oxygen in the atmosphere, so that application of an air barrier agent is not required.

As described above, when the composition of the present invention and its polymerization method are used, a high degree of polymerization can be ensured by photopolymerization after room temperature polymerization. Therefore, it is not necessary to obtain a high degree of polymerization at the room temperature polymerization stage. The curing speed can be freely set so that the operation can be performed with a sufficient margin.

Further, the present invention differs from the conventional photopolymerization method in that once polymerization is carried out at room temperature and then further polymerization is carried out by irradiation with light, all of the drawbacks found in the conventional photopolymerization method are eliminated. Can be eliminated.

For example, in the present invention, since the polymerization is carried out at room temperature in advance, the polymerization at room temperature is guaranteed at a minimum. Therefore,
Even in the case of a thick material, the problem that the inside does not harden is eliminated. In addition, there is no fear that unpolymerized portions will not be exposed to light.

On the other hand, in the case of the conventional photopolymerizable material, the degree of polymerization is zero unless light is irradiated, and therefore, the risk when light is not irradiated becomes extremely large.

In addition, in the case of the conventional photopolymerizable material, since polymerization hardening starts from the surface of the material, shrinkage occurs due to polymerization from the surface, and as a result, the deformation of the material becomes very large.

However, in the method of the present invention, the preceding polymerization at room temperature proceeds more uniformly from the inside, so that the influence of curing shrinkage is very small. Most of the polymerization shrinkage occurs due to the reaction at room temperature, so that the subsequent polymerization shrinkage due to light is suppressed as much as possible.

Furthermore, conventional photopolymerizable materials are strongly affected by polymerization inhibition by oxygen in the atmosphere, so that the degree of polymerization on the surface is low and the surface hardness is considerably low.

However, in the present invention, since the polymerization is hardly inhibited by oxygen, the surface hardness is extremely high.

Originally, the merit of the photopolymerization method was that the operability was improved by eliminating the restriction on the operation time. However, it is possible to set the curing time so that the operation can be carried out with a sufficient margin even in the room temperature polymerization method by the combined use with the photopolymerization. That is, in the case of the material for reconstructing the occlusal surface of the artificial denture base, the operation can be sufficiently performed if an operation time of about 10 minutes is provided at room temperature. However, if the curing time is made longer, the physical properties after room temperature polymerization become lower and the surface hardness is remarkably reduced.

However, in the present invention, the degree of polymerization is remarkably improved by performing photopolymerization after polymerization at room temperature, so that even if the degree of polymerization by room temperature polymerization is low, there is no problem. Therefore, there is no need to increase the curing speed more than necessary in order to increase the degree of polymerization, and it is possible to set an appropriate curing time according to the application.

In the present invention, light is irradiated after polymerization at room temperature. In this case, the time from the polymerization at room temperature to the irradiation with light is not particularly limited, and irradiation may be performed as needed.

That is, in the case of reconstructing the occlusal surface of the artificial denture base artificial tooth, light irradiation may be performed after the trimming of the unnecessary portion is completed and the shape is corrected by the bar, or the light irradiation is performed after the trimming is completed. After that, the shape may be corrected.

However, if the time from room temperature polymerization to irradiation with light becomes extremely long, the photopolymerization reaction becomes extremely difficult to occur. Therefore, light irradiation is preferably performed within several hours after room temperature polymerization. Even when light irradiation is performed after one day, photopolymerization occurs, but the degree is much lower than when irradiation is performed immediately after room temperature polymerization. In addition, even if light irradiation at any stage within several hours after room temperature polymerization,
Approximately the same degree of polymerization is obtained.

The present invention is characterized in that the degree of polymerization by room temperature polymerization is greatly increased by a photopolymerization reaction. That is,
There is a limit to the reaction at room temperature, not all of the monomers can be polymerized, and considerable monomers remain in the material as unreacted materials. It acts as a plasticizer and reduces the hardness of the material. By irradiating light at this stage, the monomer remaining unreacted reacts, and as a result, the hardness of the material is dramatically improved.

[0035]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composition for reconstructing an occlusal surface of a denture base artificial tooth of a powder-liquid mixture type, which will be described in detail below. First, the liquid agent has a methacrylate capable of radical polymerization and a radical polymerization accelerator as essential components. Here, the methacrylate capable of radical polymerization includes methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, n-butyl methacrylate, and 2-hydroxyethyl methacrylate. And monofunctional methacrylates such as ethylhexyl methacrylate and lauryl methacrylate, and polyfunctional methacrylates such as ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, and trimethylolpropane trimethacrylate. These may be used alone or in combination of two or more.

Next, examples of the radical polymerization accelerator used in the liquid preparation include tertiary amines such as NN'-dimethylaniline, NN'-diethylaniline, NN'-dimethylparatoluidine, and paratolyldiethanolamine. These may be used alone or in combination of two or more.

The amount of the radical polymerization accelerator varies depending on the type of methacrylate used, the type and amount of the radical polymerization initiator described later, and the required curing time at room temperature. Is preferably set in the range of 0.05 to 5% by weight based on the total amount of Here, if the amount of the radical polymerization accelerator is less than 0.05% by weight, the polymerization reaction at ordinary temperature is significantly slowed down, the polymerization reaction by light irradiation does not sufficiently occur, and the hardness of the cured product is extremely low. It will be low. If the amount is more than 5% by weight, a sufficient accelerating effect cannot be obtained, and adverse effects such as discoloration will be increased.

Examples of the methacrylate polymer or copolymer that can be used in the powder include polymethyl methacrylate,
Polymers such as polyethyl methacrylate, methyl methacrylate / ethyl methacrylate copolymer, and methyl methacrylate / n-butyl methacrylate copolymer are included. These may be used alone or as a blend of two or more.

The polymer or copolymer may have a wide range of molecular weights, but may have an average molecular weight of 10,000 to 10
Those in the range of 100,000 are suitable. The particle diameter is preferably as small as possible in order to improve the solubility in the liquid component, and preferably in the range of 10 μm to 100 μm.

The radical polymerization initiator that can be used in the powder includes diacyl peroxides such as benzoyl peroxide and lauroyl peroxide.

The amount of these radical polymerization initiators added is
Depending on the type of methacrylate to be used, the type and amount of radical polymerization accelerator, and the required curing time at room temperature, 0.05 to 5% by weight based on the total amount of methacrylate polymer or copolymer used. % Is preferable. Here, the addition amount is 0.05% by weight.
If the temperature is lower, both the room-temperature polymerizability and the photopolymerizability decrease, and sufficient hardness cannot be obtained. In addition, the addition amount is 5
If it is more than 10% by weight, a sufficient accelerating effect cannot be obtained.

In order to impart photopolymerizability to the material used in the present invention, a photopolymerization initiator is added to at least one of a powder or a liquid. The photopolymerization initiator that can be used here is not particularly limited, but a chain α-diketone compound such as benzyl, 2.3-pentanedione, a finger α-diketone compound such as camphorquinone, anthraquinone , Polynuclear quinones such as naphthoquinone, 2-methyl-1.4-naphthoquinone, 1.2-
And polynuclear quinone derivatives such as benzanthraquinone. These may be used alone or in combination of several types.

The amount of the photopolymerization initiator varies depending on the composition of the liquid agent and the powder component, but is preferably in the range of 0.01 to 3% by weight. Here, the addition amount is 0.01
When the amount is less than 3% by weight, the polymerization reaction does not efficiently occur when irradiated with light, and when the amount is more than 3% by weight, the effect hardly changes, and conversely, the yellowing of the material becomes remarkable. Occurs. In addition, these photopolymerization initiators may be added to any of powders and liquids.

As the light irradiator used in the present invention, there is a visible light irradiator currently used for dentistry. In the reconstruction of denture base artificial teeth occlusal surface, when using over a large area like a complete denture, it is preferable to use a light irradiator for engineering, but use it over a narrow area like a pole denture In this case, a hand-type light irradiator used for the filling composite resin is sufficient. The irradiation time depends on the reactivity of the material used, but is generally 1-2
A predetermined hardness can be obtained in about 0 minutes.

Experimental Examples Specific experimental examples of the present invention are shown below. However, the present invention is not limited to the experimental examples shown here. [Experimental Example 1] 80 parts of methyl methacrylate, 10 parts of 2-hydroxyethyl methacrylate, 10 parts of trimethylolpropane trimethacrylate, and 0.5 part of NN'-dimethylparatoluidine were put in a beaker and mixed for 10 minutes to prepare a liquid preparation. .

100 parts of a methyl methacrylate / ethyl methacrylate copolymer (molar ratio = 3/2) having an average particle diameter of 50 μm and an average molecular weight of 250,000, 0.5 part of benzoyl peroxide, and 0.3 part of camphorquinone were put into a ball mill. And mixed for 10 minutes to prepare a powder.

1 g of the liquid preparation and 2 g of the powder preparation were mixed in a polyethylene container, and a thermocouple was inserted therein. Measure the temperature inside the sample from the start of mixing, find the time when the maximum temperature was recorded,
It was taken as the cure time.

A sample obtained by mixing powder and liquid at the same ratio is 25 ×
The mold was filled in a 25 × 3 mm Teflon mold, and the upper surface was pressed with a Teflon plate and cured as it was. 10 from the start of powder-liquid mixing
After a minute, the test piece was taken out of the mold and irradiated with light for 10 minutes using a light irradiator equipped with two 125 w halogen lamps. After the irradiation, the surface of the test piece was polished with a # 800 water-resistant abrasive paper, and the surface hardness (Vickers hardness) was measured using an Akashi microhardness tester. After storing the test piece in a thermostat at 37 ° C. for 7 days, the surface was measured again. Further, the deformed state of the test piece after light irradiation was visually observed. Table 1 shows the results.

[0049]

[Table 1]

EXPERIMENTAL EXAMPLE 2 Except that the amount of NN′-dimethylparatoluidine in the liquid component shown in Experimental Example 1 was 0.25% by weight,
An experiment similar to that shown in Experimental Example 1 was performed. Table 1 shows the results.

[Experimental Example 3] The same experiment as in Experimental Example 2 was performed except that the test piece was taken out from the mold and irradiated with light 2 hours later. Table 1 shows the results.

Comparative Example 1 A methyl methacrylate / ethyl methacrylate copolymer having an average particle diameter of 50 μm and an average molecular weight of 250,000 (molar ratio = 3)
/ 2) 100 parts and benzoyl peroxide 0.5 part were put in a ball mill and mixed for 10 minutes to prepare a powder.

2 g of this powder and the liquid 1 used in Experimental Example 1
g was mixed in a polyethylene container, and the curing time was measured in the same manner as in Experimental Example 1.

A sample mixed at the same ratio was 25 × 25 ×
The mixture was filled in a 3 mm Teflon mold, and the upper surface was pressed against a Teflon plate and cured as it was. Twenty minutes after the start of the mixing of the powder and liquid, the test piece was taken out of the mold, the surface was polished with a water-resistant abrasive paper No. 800, and the surface hardness was measured using an Akashi microhardness tester. Further, the deformed state of the test specimen after curing was visually observed. Table 1 shows the results.

Comparative Example 2 The same experiment as in Comparative Example 1 was carried out using the powder used in Comparative Example 1 and the liquid used in Experimental Example 2. Table 1 shows the results
Shown in

Comparative Example 3 A liquid preparation was prepared by placing 80 parts of methyl methacrylate, 10 parts of 2-hydroxyethyl methacrylate, and 10 parts of trimethylolpropane trimethacrylate in a beaker and mixing for 10 minutes.

An experiment was carried out in the same manner as in Experimental Example 1 using this liquid and the powder used in Experimental Example 1. Table 1 shows the results.

As shown in the experimental results in Table 1, in Experimental Examples 1, 2, and 3 of the present invention, sufficient surface hardness was obtained and there was almost no deformation, whereas Comparative Examples 1, 2, and 3 had low surface hardness. In Comparative Example 3, the deformation was very large.

[0059]

Since the present invention is configured as described above, it has the following effects. Radical polymerizable methacrylate, a liquid agent composed of a radical polymerization accelerator, a methacrylate polymer or copolymer, at least one of a powder composed of a radical polymerization initiator, a photopolymerization initiator is blended, and the mixture of the powder and the liquid is mixed. After polymerization and curing at room temperature, the photopolymerization reaction is caused by irradiating visible light to increase the degree of polymerization, whereby the physical properties of the polymer, particularly the surface hardness, can be further improved. In this way, since photopolymerization occurs after room temperature polymerization, the curing time at room temperature can be set arbitrarily, and, at a minimum, polymerization by room temperature polymerization is guaranteed, polymerization of the surface is not hindered, and in the case of thick wall But there is no worry of poor internal polymerization,
The advantage is obtained that the unpolymerized portion does not become unpolymerized even in the portion not irradiated with light.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) A61K 6/083 A61K 6/00

Claims (2)

(57) [Claims] 1. A room-temperature polymerization-type composition comprising a liquid agent comprising a radically polymerizable methacrylate and a radical polymerization accelerator, and a powder agent comprising a methacrylate polymer or copolymer and a radical polymerization initiator. Alternatively, a denture base artificial tooth occlusal surface reconstruction characterized by mixing a photopolymerization initiator in at least one of the liquid preparations
Composition . 2. A radical polymerizable methacrylate, and liquid consisting of a radical polymerization accelerator, methacrylate polymer or copolymer, mixed-compounded with a photopolymerization initiator to at least one of the powder consisting of a radical polymerization initiator To
Irradiated with visible light after heavy together at room temperature, the polymerization process of denture base artificial teeth occlusal surface reconstruction composition characterized by increasing the degree of polymerization by causing photopolymerization.