Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1998-12-17
2001-01-16
Szekely, Peter A. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C523S116000, C524S533000, C524S558000, C526S320000, C206S063500
Reexamination Certificate
active
06174935
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a dental adhesive kit which is used for effectively adhering a dental restorative material to a tooth structure by a simple handling. More particularly, the present invention relates to a dental adhesive kit to be used for making the adhesive properties of a resin-based adhesive firm and reliable by a simple handling in adhering a dental restorative material to an enamel and a dentin.
BACKGROUND OF THE INVENTION
Following the propagation of a composite resin as a dental restorative material, it is required to undergo firm adhesion with safe and confidence between a tooth structure and the composite resin by a simple handling. As adhesion methods which have hitherto been employed, after an acid etching by phosphoric acid or citric acid and so on, a series of handling of water washing→drying→application of a primer→drying →application of an adhesive→polymerization→filling of a composite resin can be exemplified as a representative adhesion method of a restoration. In actual restoration, it is the present state that it takes time to accomplish such handling and that no adhesion with confidence is attained.
Thus, in recent years, adhesion methods for simplifying such complicated handling steps have been being investigated. For example, a new type primer is proposed in, JP-A-3-240,712 and JP-A-7-82,115. In the proposed methods using the new type primer, a tooth is treated with a self-etching primer by which it is said that an etching and a priming can be carried out simultaneously, and after drying, a bonding agent is applied. In other words, a surface of the tooth having a cavity formed therein is treated with the self-etching primer, and the self-etching primer penetrates into the tooth structure while dissolving a smear layer generated upon the cavity formation. Then, a bonding agent is applied, whereby the self-etching primer and the bonding agent are integrated and set to obtain a firm adhesive layer.
However, such kinds of self-etching primers which are commercially available at present need a polymerization catalyst and a polymerization accelerator for setting the polymerizable component in the self-etching primer, and in order to obtain a self-etching primer having good storage stability and stable adhesive capacity, the polymerization catalyst must be separated from the polymerization accelerator. For this reason, self-etching primers which are commercially available at present are constructed by a two-pack type self-etching primer of a polymerization catalyst and a poly-merization accelerator, and the two packs must be mixed with each other before the use. Accordingly, it is not always said that its handling is easy, and there may be a possibility that unstable adhesion is obtained due to a metering error.
SUMMARY OF THE INVENTION
An object of the present invention is to solve the above-described drawbacks of the conventional technologies in adhesion of a dental restorative material to a tooth structure such that the adhesion steps are complicated and take time and that no stable adhesive strength is obtained, whereby clinically satisfactory adhesives have not yet been obtained, and to provide a dental adhesive kit to be used capable of adhering a dental restoration material to a tooth structure firmly and reliably by a simple handling.
We, the present inventors made extensive and intensive investigations in order to achieve the above-described object. As a result, it has been found that when a dental adhesive kit is constructed by a combination of a one-pack type self-etching primer and a one-pack type bonding agent, wherein the one-pack self-etching primer which is free from mixing comprises a methacrylate or acrylate having an acidic group and having at least one unsaturated double bond, a water-soluble organic solvent, and water; and the one-pack bonding agent which is free from mixing comprises a methacrylate or acrylate having neither acidic group nor hydroxyl group and having at least one unsaturated double bond, a methacrylate or acrylate not having an acidic group but having a hydroxyl group and having at least one unsaturated double bond, a photopolymerization initiator, a photopolymerization accelerator, and a filler, firm and reliable adhesion of a dental restoration material to a tooth structure can be obtained by a simple handling, leading to accomplishment of the present invention.
Since the self-etching primers which have hitherto been commercially available need a polymerization initiator and a polymerization accelerator and contain components readily reactive with the polymerization accelerator, such as an acid component and water, these components must be separated from each other taking into account the storage stability and hence, the conventional self-etching primers are provided as a two-pack type self-etching primer which needs intimate mixing before the use. On the other hand, since the self-etching primer in the present invention has a very high affinity with the bonding agent, the polymerizable component in the self-etching primer is readily mixed with the polymerizable component, photopolymerization initiator and photopolymerization accelerator in the bonding agent, thereby enabling one to undergo the photopolymerization. Thus, according to the present invention, an adhesive kit having superior handling and adhesive durability can be provided as a one-pack type self-etching primer and a one-pack type bonding agent, respectively.
When the dentin is treated with the one-pack self-etching primer free from mixing according to the present invention, the (meth)acrylate monomer having an acidic group in the self-etching primer dissolves therein a smear layer as tailings at the time of cavity preparation and penetrates into the dentin while decalcifying the dentin. Then, after drying the water-soluble organic solvent in the self-etching primer, when the one-pack type bonding agent with superior penetration properties is applied onto a tooth surface, the polymerizable component in the self-etching primer having penetrated into the dentin is integrated with the bonding agent, whereby the resin monomer reliably penetrates into the decalcified dentin. At this time, the polymerizable component in the self-etching is uniformly mixed with the photopolymerization initiator and the photopolymerization accelerator in the bonding agent, and the monomer component having thoroughly penetrated into the decalcified dentin is polymerized to form a hybrid layer. Thus, high-strength adhesion is attained.
Also, when the enamel is treated with the one-pack self-etching primer free from mixing according to the present invention, the (meth)acrylate monomer having an acidic group in the self-etching primer dissolves therein a smear layer as tailings at the time of cavity preparation and removes it. At the same time, the (meth)acrylate monomer having an acidic group decalcifies the enamel and penetrates into the enamel while forming unevennesses based on an enamel prism and generating a finer uneven structure based on the crystal structure of hydroxyapatite constituting an enamel on the surface. Then, when the one-pack type bonding agent with superior penetration properties is applied thereonto, the resin monomer is integrated with the polymerizable component in the self-etching primer and polymerized for setting. Thus, firm adhesion is attained.
That is, the dental adhesive kit according to the present invention comprises a combination of:
(i) a self-etching primer comprising (A) from 1.0 to 50% by weight of a methacrylate or acrylate having an acidic group and having at least one unsaturated double bond, (B) from 1.0 to 98% by weight of a water-soluble organic solvent, and (C) from 1.0 to 90% by weight of water; and
(ii) a bonding agent comprising (D) from 10 to 90% by weight of a methacrylate or acrylate having neither acidic group nor hydroxyl group and having at least one unsaturated double bond, (E) from 10 to 90% by weight of a methacrylate or acrylate not having an acidic group but
Akahane Shoji
Hirota Kazuo
Matsunae Kaori
GC Corporation
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Szekely Peter A.
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