JPH1180593A - Primer composition for bracket made of plastic and usage of the same composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the adhesion of a bracket made of a plastic without any adhesion to a photopolymerizable type adhesive for orthodontics. SOLUTION: This primer composition is used to improve the adhesion of a bracket made of a plastic to an adhesive by coating the surface of the bracket therewith when bonding the bracket made of the plastic to a dentin with a photopolymerizable type adhesive for orthodontics. In this case, the primer composition is substantially composed of methyl methacrylate, hydroxyethyl methacrylate or the methyl methacrylate and triethylene glycol dimethacrylate. A photopolymerization initiator may be added to the composition to afford a photopolymerizable type primer composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a primer composition for a bracket for firmly bonding a bracket and a tooth material when the orthodontic bracket is directly attached to a tooth by a direct bonding method. The present invention relates to a primer composition capable of significantly increasing the adhesive strength between a plastic bracket and a light-curable orthodontic adhesive.

[0002]

2. Description of the Related Art Orthodontic treatment using a bracket is
While fixing the bracket on the surface of each tooth, passing an arch wire through each bracket, applying an external force such as pressing, pulling back, twisting, etc. to the teeth by the tensile force of this arch wire, displacing the tooth row to the correct position and direction It is to make corrections. Previously, when fixing the bracket to the tooth surface, a metal ring (band) was attached to the tooth and the bracket was bonded to this band, but after the direct bonding method of bonding the bracket directly to the tooth was developed. In general, a method is used in which a band is used for a molar part, and a front part or a premolar part is directly attached to a tooth. Using a band on the molars is a position that is difficult to see from the outside, and the strongest force such as an arch wire is applied,
This is because the adhesive strength of the direct bonding method is insufficient. For teeth without a band, it is common to etch the tooth material to increase the adhesive strength.

[0003] The adhesive used in the direct bonding method is called an orthodontic adhesive, and is generally called B
is-GMA, that is, a composite resin containing an acrylic monomer such as 2,2′-bis [4- (3-methacryloyloxy-2-hydroxypropoxy) phenyl] propane as a main component (for example, trade name “System 1”:
Omco) and glass ionomer cement (for example, trade name "Fujiorso": manufactured by GC Corporation) are known. Therefore, glass ionomer cement is preferably used.

Further, from the viewpoint of the bonding operation, a photopolymerization type (for example, trade name “Fujiorso LC”: manufactured by GC Corporation), in which the curing timing can be controlled more easily than a chemical polymerization type in which the curing timing of the adhesive cannot be controlled. , "Sun Cure" manufactured by Sankin Co., Ltd.) has become mainstream because of its superior operability.

On the other hand, metal brackets have been mainly used in the past, but since the metal color is conspicuous and inferior in aesthetics, recently, milky white, translucent or transparent ceramics or plastics have been used. Brackets have been used. As plastic brackets, those made of polycarbonate, acrylic, or the like having excellent transparency are known.

[0006]

However, plastic brackets have a problem that they do not adhere to a light-curing type orthodontic adhesive or have very weak adhesion even if they adhere. It is preventing its spread. Therefore, an object of the present invention is to improve the adhesiveness between the plastic bracket and the light-curing type orthodontic adhesive.

[0007]

According to the present invention, a plastic bracket is applied to a tooth surface with a light-curing orthodontic adhesive, and the plastic bracket is applied to the surface of the bracket.
A primer composition used to improve the adhesion between the bracket and the ionomer cement, wherein the main components of the primer composition are methyl methacrylate (hereinafter abbreviated as MMA) and hydroxyethyl methacrylate ( Hereinafter, a type that is a mixture of HEMA (hereinafter, abbreviated as MMA-HEMA system) and a type that is a mixture of MMA and triethylene glycol dimethacrylate (hereinafter, abbreviated as TEGDMA) (hereinafter, MMA-). TEG type). In addition, the MMA-HEMA system and the MMA-TEG system are each classified into a type not containing a photopolymerization initiator and a type containing a photopolymerization initiator, that is, the primer composition of the present invention is divided into four types. Divided.

When the primer composition is an MMA-HEMA system, the ratio of MMA to HEMA is preferably 8: 2 to 1: 9 (weight ratio), and when the primer composition is an MMA-TEG system, the ratio of MMA to TEGDMA is Is preferably 9: 1 to 1: 9.

When the primer composition does not contain a photopolymerization initiator, it is preferable that the primer be applied to a bracket and dried, and then contacted with a photopolymerization-type orthodontic adhesive without light irradiation before use. . When the primer composition contains a photopolymerization initiator, it is preferable that the primer be applied and dried, and then irradiated with light, and then contacted with a photopolymerization-type orthodontic adhesive. The photopolymerization of the primer may be performed simultaneously with the photopolymerization of the photopolymerization-type orthodontic adhesive.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The primer composition of the present invention is classified into a first type having no photopolymerizability (hereinafter, referred to as a first primer composition) and a second type having photopolymerizability (hereinafter, referred to as a first type). Second primer composition). In addition, these primer compositions are respectively MMA-HEMA type and MMA-HEMA type.
It is divided into MA-TEG system. Only when MMA and HEMA or MMA and TEGDMA are used in combination, the adhesiveness between the plastic bracket and the photocurable orthodontic adhesive can be significantly improved.

As the plastic bracket, a transparent and tough material such as polycarbonate, polyarylate, polysulfone, or acrylic resin can be used.
It is optimal to use a combination of the toughest polycarbonate bracket and the primer composition of the present invention.

The bracket may be made of not only a plastic bracket but also a metal part only for inserting the arch wire. Further, the primer composition of the present invention can be applied to a bracket whose durability is increased by adding an inorganic filler or a reinforcing fiber to the resin material.

As the orthodontic adhesive, a photopolymerizable adhesive is used. This is because the timing of curing is easier to control and the operability is better than in the chemical polymerization type. Further, the plastic bracket and the photopolymerizable adhesive did not adhere to each other unless the primer composition of the present invention was used, and the two could not be used in combination. It is premised on the combination use of a photo-curable orthodontic adhesive. Among the photopolymerization-type orthodontic adhesives, a photopolymerization-type glass ionomer cement, which is particularly excellent in biocompatibility, adhesiveness to dentin, caries prevention effect, and the like, is preferable.

The first primer composition having no photopolymerizability is
Substantially MMA and HEMA, or MMA and TEGDM
A. The photopolymerizable second primer composition comprises MMA and HEMA, or MMA and TEGDMA.
And a photopolymerization initiator. In addition, the meaning of "substantially" means that other components such as a monomer and a solvent may be added as long as the content is about 5% by weight or less in the composition.

The photopolymerization initiator used in the second primer composition includes diketones such as camphorquinone, 9,10-phenanthrenequinone and naphthoquinone, and N, N, so that photopolymerization can be initiated by visible light. N-
Dimethylamino-p-toluidine, butyldiethanolamine, N, N-dimethylaminoethyl methacrylate, morpholinoethyl methacrylate, ethyl-p-
Use of a combination of tertiary amines such as (N, N-dimethylamino) benzoic acid, 2-methacryloxyethyl-p- (N, N-dimethylamino) benzoic acid, dimethylaminobenzoic acid and esters thereof. Is preferred. Also,
The photopolymerization initiator is preferably added in an amount of 0.1 to 3% by weight in the composition.

When both the first primer composition and the second primer composition are of the MMA-HEMA type, MMA and HE are used.
MA: 8: 2-1: 9 as weight ratio of both, MMA
-In the case of TEG system, MMA and TEGDMA are 1: 9
９9: 1 is preferred. Even outside this range, the adhesion between the plastic bracket and the photopolymerization-type orthodontic adhesive is improved by using the primer composition of each system as compared with the case where the primer composition is not completely treated. But 5MPa
In order to obtain the above adhesive strength, it is recommended to use one within the above range.

Further, in order to obtain a strong adhesive force of 10 MPa or more, in the first primer composition, MMA and H
EMA near 7: 3, MMA and TEGDMA 3:
It is preferable to be around 7. In the case of the second primer composition, it is preferable to photopolymerize MMA and HEMA in the range of 7: 3 to 3: 7 and MMA and TEGDMA in the range of 7: 3 to 1: 9.

When the plastic bracket is adhered to the dentin using a photopolymerizable orthodontic adhesive using the first primer composition having no photopolymerizability, the first bracket is applied to the surface of the bracket.
Apply the primer composition, at room temperature, or with hot air,
After being appropriately dried, it is brought into contact with a photopolymerizable orthodontic adhesive. The expression "contact" includes both a case where a photopolymerizable adhesive is applied to the surface of the primer on the bracket and a case where an adhesive is applied to the tooth side and the bracket is adhered to the adhesive.

In the case of the second primer composition, after the primer composition is applied to the surface of the bracket, dried appropriately at room temperature or with hot air or the like, and then irradiated with light to complete the photopolymerization of the primer. It is preferable to adopt a method of contacting with a light-curing type orthodontic adhesive. Further, a method of simultaneously performing the photopolymerization of the primer and the photopolymerization of the adhesive, that is, a method of applying the second primer composition and then irradiating with the adhesive without irradiating the light without applying the light, is adopted. Can also. However, in the case of the MMA-TEG system, the higher the photopolymerization of the primer, the higher the adhesive strength.

[0020]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which do not limit the present invention.
Modifications and alterations that do not depart from the spirit described below are all included in the technical scope of the present invention.

EXAMPLE Two adherends made of polycarbonate (hereinafter abbreviated as PC) were used to study the effect of improving the adhesion between a plastic bracket and a light-curing type orthodontic adhesive by applying a primer. An experiment was conducted in which these were made and bonded with a light-cured glass ionomer cement. One of the adherends made of PC is molded into a plate having a side of 1 cm and a thickness of 3 mm using a polycarbonate resin manufactured by Sankin Kogyo Co., Ltd. It is embedded. The other is 5m in diameter
m and 5 mm in height. In each of the adherends, the adhesive surface was polished with water-resistant abrasive paper (# 600). The primer composition is an MMA-HEMA system, MMA
The composition was changed for both the -TEG type and the experiment was performed with two types of type 1 (first primer composition having no photopolymerizability) and type 2 (second primer composition of photopolymerization type). In type 2, camphorquinone and dimethylaminoethyl methacrylate were used as a photopolymerization initiator in a weight ratio of 1: 1 and a total of 2% by weight in the primer composition. The adhesion test method is as follows.

First, both the plate-shaped adherend made of PC and the cylindrical adherend made of PC are applied so that the primer composition spreads over the entire surface of the bonding surface.

In the case of the type 1 primer composition,
After coating, the coated surface is dried with compressed air. In the case of the type 2 primer composition, after coating and drying, the primer is cured by irradiating light with a visible light irradiator (manufactured by GC: "Luxor") for 40 seconds.

After kneading a photopolymerizable glass ionomer cement (manufactured by 3M) at a predetermined powder-liquid ratio, the mixture is applied to a columnar adherend made of PC, placed on a plate adherend, and weighed 200 g. Both were pressed by a constant load pressure test apparatus. Immediately after the pressure welding, a visible light irradiator (GC: “Luxor”)
Light is applied for 0 seconds to cure the cement.

The obtained adhesive test piece was allowed to stand for 24 hours at 37
After immersion in hot water at ℃, the compression shear adhesive strength is measured with a universal compression tester. The adhesive strength is an average value of 10 test pieces. Statistical processing was also performed using Scheffe's analysis of variance.

FIG. 1 (MMA-H)
(EMA system) and FIG. 2 (MMA-TEG system).
When the primer was not treated, the adherend made of PC and the glass ionomer cement did not adhere. As is clear from FIG. 1, when the composition ratio of MMA and HEMA is the same, it can be seen that the type 2 photopolymerizable primer composition has a higher adhesiveness improving effect than type 1. Also, MM
When A and HEMA are 7: 3, both Type 1 and Type 2 show significantly higher adhesive strength than the other ratios. Therefore, in order to obtain a strong adhesive force of 10 MPa or more, in the first primer composition, MMA and HEM
It can be seen that when photopolymerizing the second primer composition with A at around 7: 3, MMA and HEMA should be in the range of 7: 3 to 3: 7.

As is apparent from FIG. 2, the MMA-
In the TEG system, MMA: TEGDMA is 7: 3 to 1: 9.
It was found that the use of the second primer composition of the above shows a very high adhesive strength at the level of 20 MPa. Therefore,
In order to obtain an adhesive force of 10 MPa or more in the MMA-TEG system, in the case of the first primer composition, MMA: TEGD
MA in the vicinity of 3: 7, in the case of the second primer composition,
MMA: TEGDMA should be in the range of 7: 3 to 1: 9.

[0028]

According to the present invention, a plastic bracket having low adhesiveness and a photopolymerization-type orthodontic adhesive can be bonded very firmly by applying the primer composition of the present invention. Therefore, the plastic bracket and the light-curing type orthodontic adhesive, which had respective advantages but could not be used in combination in the past, can be directly attached to the tooth material by the direct bonding method, and the esthetics are high. Correction has become possible. In addition, if glass ionomer cement is used as an adhesive, excellent adhesion is maintained over a long period of time even when a bracket is attached to a tooth without being etched, so that orthodontic work is simplified and tooth quality is safe. It is.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the composition ratio of an MMA-HEMA-based primer composition and adhesive strength.

FIG. 2 is a graph showing the relationship between the composition ratio of an MMA-TEG-based primer composition and adhesive strength.

Claims (8)

[Claims] When a plastic bracket is adhered to a tooth with a light-curing orthodontic adhesive, the plastic bracket is applied to the surface of the bracket so as to improve the adhesiveness between the bracket and the adhesive. A primer composition for a plastic bracket, characterized in that the primer composition substantially comprises methyl methacrylate and hydroxyethyl methacrylate. 2. A plastic bracket is used to improve the adhesion between the bracket and the adhesive by applying the plastic bracket to the surface of the bracket when bonding the plastic bracket to the dentin with a light-curing orthodontic adhesive. A primer composition for plastic brackets, characterized in that the primer composition substantially comprises methyl methacrylate, hydroxyethyl methacrylate and a photopolymerization initiator. 3. The method according to claim 1, wherein the primer composition comprises methyl methacrylate and hydroxyethyl methacrylate in a ratio of 8: 2.
The primer composition for a plastic bracket according to claim 1 or 2, which is contained in a weight ratio of 1: 9. 4. When a plastic bracket is adhered to tooth material with a light-curing type orthodontic adhesive, the plastic bracket is applied to the surface of the bracket to improve the adhesiveness between the bracket and the adhesive. A primer composition for a plastic bracket, characterized in that the primer composition substantially comprises methyl methacrylate and triethylene glycol dimethacrylate. 5. A plastic bracket is used to improve the adhesion between the bracket and the adhesive by applying the plastic bracket to the surface of the bracket when the plastic bracket is adhered to the dentin with a light-curing type orthodontic adhesive. A primer composition for a plastic bracket, characterized in that the primer composition substantially comprises methyl methacrylate, triethylene glycol dimethacrylate and a photopolymerization initiator. 6. The primer composition for a plastic bracket according to claim 4, wherein the primer composition comprises methyl methacrylate and triethylene glycol dimethacrylate in a weight ratio of 9: 1 to 1: 9. 7. The plastic bracket according to claim 1 or 4, wherein the plastic bracket is adhered to the dentin with a light-curing type orthodontic adhesive. A method of using a primer composition for a plastic bracket, wherein the primer composition is brought into contact with a photopolymerization-type orthodontic adhesive without irradiation. 8. A plastic bracket according to claim 2 or 5, wherein the plastic bracket is adhered to the dentin with a light-curing type orthodontic adhesive, and the surface of the bracket is coated with the plastic bracket primer composition. A method for using a plastic bracket primer composition, which comprises contacting with a light-curable orthodontic adhesive after irradiation.