JPS61275206A - Material for mending denture base - Google Patents

Abstract

PURPOSE:To provide the titled mending material composed of a monomer mixture containing methyl methacrylate, etc., at a specific ratio, and capable of mending a denture base made of a thermoplastic resin easily without causing stress-cracking. CONSTITUTION:A monomer mixture containing (A) 10-60(wt)% methyl methacrylate of formula I (R is CH3), (B) 1-60% aliphatic methacrylate of formula I (R is an aliphatic group other than CH3, preferably 2-6C alkyl) and (C) 5-60% dimethacrylate containing aromatic ring, e.g. a bisphenol A dimethacrylate such as the compound of formula II, etc., is stirred and mixed homogeneously at room temperature to obtain the objective material. The mixture can be used for the mending of a plastic denture base produced e.g. by the injection molding of a thermoplastic resin such as a polysulfone resin. EFFECT:It has excellent handleability and high compatibility of three monomers. A homogeneous liquid having moderate viscosity can be produced and the mending of a denture base can be carried out in high quality.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to the repair of resin denture bases obtained by molding thermoplastic resin by injection molding, extrusion molding, transfer molding, compression molding, etc. Regarding materials for use.

[Conventional technology]

Conventional resin denture bases have been produced using acrylic resin by a pressure molding method that involves heat polymerization of polymers and monomers. This has the advantage that repair is easy because the same acrylic polymer powder and acrylic polymer powder are used as repair materials.

However, denture bases obtained by heating polymerization of acrylic resins are brittle, and the thin parts often break due to occlusal force, and because the heating polymerization reaction is often insufficient, residual monomers are eluted and can cause allergic reactions. It also had hygienic drawbacks, such as causing symptoms.

To overcome these drawbacks, thermoplastic resins were used, and injection molding and compression molding methods (Japanese Patent Laid-Open No. 58-1439) were developed.
Methods of manufacturing denture bases using molding methods such as , extrusion molding, and transfer molding have been proposed.

The thermoplastic resin used in these methods does not undergo thermal deterioration during molding, has an appropriate viscosity, has good moldability, and can be colored in a color close to the gums. It is required to have appropriate rigidity, moisture resistance, and high toughness.

Therefore, polystyrene, polymethyl methacrylate, polymethyl pentene-1, transparent nylon, polycarbonate, polyarylate, polyester carbonate,
Polyethylene terephthalate, transparent ABS, polysulfone resins, etc. are used, and among them, polysulfone resins such as polysulfone and polyethersulfone are preferred because they have excellent moisture resistance, rigidity, and toothbrush abrasion resistance.

Among them, UCC's polysulfone Udel@ which has a structure and ICI's polyethersulfone Vict which has a structure
r ex @ is preferred.

[Problems to be solved by the invention and means for solving them]

The thermoplastic resins mentioned above, especially polysulfone resins, which are preferred for denture bases, have high mechanical strength and excellent impact resistance, but they tend to cause stress cranking when they come into contact with acrylic monomer liquid, so conventional acrylic resins Immediately polymerized repair resins containing acrylic monomers and polymers used in denture bases have a problem in that their use is limited and the scope of application is narrow.

The present invention provides a denture base repair material that can easily repair a denture base molded from a thermoplastic resin such as a polysulfone resin, particularly a polysulfone resin, without causing stress cranking.

That is, the present invention consists of a monomer mixture containing 10 to 60% by weight of methyl methacrylate, 10 to 60% by weight of an aliphatic methacrylate other than methyl methacrylate, and 5 to 60% by weight of dimethacrylate containing an aromatic ring. This invention relates to denture base repair materials.

It is commonly used as a resin for denture bases.

Examples of aliphatic methacrylates other than methyl methacrylate used in the present invention include R being ethyl, normal propyl, isopropyl, normal butyl, 5ee-butyl, tart-butyl, isobutyl, allyl, phenyl, benzyl, 2-ethylhexyl, -Hydroxyethyl, cyclohexyl, lauryl, n-butoxyethyl, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, etc. Among these, those in which R is an alkyl group having 2 to 6 carbon atoms are preferred.

Among them, butyl methacrylate is preferred, and isobutyl methacrylate and normal butyl methacrylate are particularly preferred from the viewpoint of handleability, odor, and stress cranking properties of the thermoplastic resin.

As the aromatic ring-containing dimethacrylate used in the present invention, bisphenol A-based dimethacrylates are preferred because of their good handling and workability. For example, 2.2'
-di(4-methacryloxyphenyl)pronof 2.2'-di(4-methacryloxyethoxyphenyl)
Propane 2,2'-di(4-methacryloxyjethoxyphenyl)propaneClI2 2,2'-bis(4-(3-methacryloxy-2-hydroxypropoxy)phenyl)pronokun (hereinafter Bis
-GMA) (n=an integer of 2 to 5) is a dimethacrylate used as a composite resin for dental fillings.

Among these, Bis-GMA is particularly preferred in terms of viscosity and physical properties after repair.

Next, these compositions will be described.

(2) When methyl methacrylate exceeds 60% by weight, cranking tends to occur in thermoplastic resins, especially polysulfone resins, which is noticeable in areas with large residual strains. If the amount is less than 10% by weight, the compatibility with the acrylic polymer powder (generally polymethyl methacrylate) used in combination as a repair material will be insufficient, so the repair agent will not be uniform and a good repair effect will not be obtained.

Further, even if (1) is 10 to 60% by weight, if (2) the aliphatic methacrylate other than methyl methacrylate is less than 10% by weight, the viscosity becomes high and the handleability becomes inappropriate.

On the other hand, if (2) exceeds 60% by weight, the hardness of the repaired area will be insufficient when used in combination with the acrylic polymer powder.

Further, (2) If the amount of dimethacrylate containing an aromatic ring is less than 5% by weight, the hardness of the repaired part will be insufficient, and if it exceeds 60% by weight, the viscosity will become too high, making it difficult to handle.

In consideration of handleability, odor, cracking property of the thermoplastic resin, hardness of the repaired part, etc., those containing 020 to 40% by weight, 040 to 60% by weight, and 010 to 30% by weight are particularly preferred.

The method for preparing the monomer mixture of the present invention is limited to a uniform stirring and mixing method.

If necessary, a crosslinking agent such as ethylene dimethacrylate, a reaction inhibitor such as hydroquinone or monomethyl ether, a coloring agent, a reinforcing agent, etc. may be added to the monomer mixture of the present invention within a range that does not significantly reduce its function as a repair material. It can be used by mixing an appropriate amount.

As the acrylic polymer powder used in combination with the monomer mixture of the present invention during repairs, commercially available polymer powders for repairing acrylic denture bases are commonly used.

The main component of the acrylic polymer powder is polymethyl methacrylate, and its form is bead-like or flake-like.

The powder contains benzoyl peroxide (0,3~
3.0%).

An activator or co-catalyst and a coloring agent may also be included to achieve the desired color after polymerization.

The method of repair using the monomer of the present invention is not particularly limited, and methods generally applied to repair of acrylic denture bases can be applied.

For example, according to the pressureless method, the monomer and polymer are placed in separate dasoben glass, the cavity is first filled with the monomer, and then the tip of a brush made of sable hair is filled. The monomer-containing tip is brought into contact with a polymer, and a small amount of polymer powder is attached to form a small dumpling, that is, a dumpling made of powder particles and the monomer. Immediately apply this bead made at the tip of the brush to the bottom of the cavity. This fluid mixture flows easily over the cavity floor, which is already wetted with monomer, and the repair is carried out by repeating this operation many times until the entire cavity is filled.

As stated above, when the monomer mixture of the present invention is used together with acrylic polymer powder to repair thermoplastic resin denture bases by the brush-laying method described above, it is easy to handle and prevents cracks from occurring in the denture base. The hardness of the repaired area is also good.

This is because methyl methacrylate alone is not a thermoplastic resin,
Crank occurs especially in areas with large residual stress,
It is presumed that this is because the blending of methacrylates other than methyl methacrylate has the effect of improving the crank resistance of the resin.

Dimethacrylate containing an aromatic ring, which is a polyfunctional monomer, compensates for the decrease in hardness of the repaired area due to the decrease in reactivity due to the combination of methacrylate, and the affinity of the three monomers is extremely good, resulting in a uniform mixed solution. Since the viscosity is also appropriate, it is presumed that good repair can be performed.

The present invention will be specifically explained below using examples, but the present invention is not limited to these examples in any way.

Example 1 After heating the flask in which the denture base wax model was embedded to soften and flow the wax, polyether sulfone (manufactured by ICI, Victr) was placed on the plaster mold at the bottom of the flask for denture base molding. A U-shaped molded product colored to resemble gums (e x04100G) was placed and the molded product was softened by blowing hot air at 380°C, and then the upper flask in which the porcelain tooth was embedded was bonded and compressed. It was compression molded using a molding machine, and then allowed to cool naturally.

After cooling, the upper and lower flasks were separated and the denture base was taken out.

As repair materials: 40% by weight of methyl methacrylate, 40% by weight of isobutyl methacrylate, BiS-GMA2
0% by weight was mixed and stirred to prepare a homogeneous liquid. Using the monomer mixture and a commercially available acrylic denture base repair powder polymer (UNI-FAST powder manufactured by Menji Dental Industry ■),
In order to improve the adhesion between the repair agent and the denture base, the predetermined repair area was coated with a methylene chloride solution containing 5% by weight of polymethyl methacrylate and 5% by weight of polycarbonate, and then repaired using a legal brush-on method. .

The denture base had a good appearance and strong adhesion, with no abnormalities such as crank formation observed in the areas around the porcelain teeth where the residual stress is estimated to be the greatest.

Example 2 All procedures were carried out except that instead of using the monomer mixture of Example 1 as the repair material, a mixture of 40% by weight methyl methacrylate, 30% by weight cyclohexyl methacrylate, and 30% by weight Bis-GMA was used. An experiment similar to Example 1 was conducted.

As in Example 1, good repair was achieved with no cranking occurring on the denture base.

Comparative Example The same experiment as in Example was conducted except that methyl methacrylate was used instead of the monomer mixture of Example 1.2 as a repair material.

Cracks had occurred in the repaired areas of the polyethersulfone denture base, which caused problems in use.

As is clear from the above, by using the monomer mixture of the present invention, repair of denture bases made of thermoplastic resin, especially polysulfone resin, can be carried out as simply and as easily as conventional acrylic resin bases. This makes it possible to take advantage of the many advantages of this denture base and expand its range of applications.

Claims (1)

[Claims] (1) [1] Methyl methacrylate 10 to 60% by weight,
[2] A denture base repair material consisting of a monomer mixture containing 10 to 60% by weight of an aliphatic methacrylate other than methyl methacrylate, and [3] 5 to 60% by weight of dimethacrylate containing an aromatic ring.