CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims the benefit of priorities from Japanese Patent Application Serial No. 2019-57535, Japanese Patent Application Serial No. 2019-57536, Japanese Patent Application Serial No. 2019-57537 and Japanese Patent Application Serial No. 2019-57538 (filed on Mar. 26, 2019), Japanese Patent Application Serial No. 2019-150038 (filed on Aug. 19, 2019), Japanese Patent Application Serial No. 2019-175309, Japanese Patent Application Serial No. 2019-175327, Japanese Patent Application Serial No. 2019-175336 and Japanese Patent Application Serial No. 2019-175354 (filed on Sep. 26, 2019), and, Japanese Patent Application Serial No. 2019-232733 (filed on Dec. 24, 2019), the contents of which are hereby incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a dental resin-reinforced glass ionomer cement composition for filling for repairing a tooth in which a form was partially lost by caries, breakages and the like and a dental resin-reinforced glass ionomer cement composition for luting for adhering or bonding a dental prosthesis device to a tooth in which a form was partially lost. More specifically the present invention relates to a powder-liquid type dental resin-reinforced glass ionomer cement composition for filling and a powder-liquid type dental resin-reinforced glass ionomer cement composition for luting which exhibit high surface curability even under wet conditions, which makes it difficult for the surface to become cloudy even if moisture comes in contact with at the initial stage of curing, exhibits high mechanical properties, low water absorption expansion and excellent coloring resistance in the set product and is also excellent in storage stability.

Description of the Related Art

In a dental practice, in order to restore aesthetically and functionally the tooth in which a form was partially lost by caries, breakages and the like, a direct restoration in which a dental composite resin for filling or a dental glass ionomer cement for filling is filled into the tooth and an indirect restoration in which a dental prosthesis device is adhered or bonded to a tooth by using a dental adhesive resin cement or a dental glass ionomer cement for luting has been performed.

Generally dental resin-based materials represented by dental composite resins for filling and dental adhesive resin cements include a matrix resin consisting of several kinds of polymerizable monomers, various kinds of fillers such as glass fillers and organic-inorganic composite fillers, and a polymerization initiator as main components and is set by photopolymerization and/or chemical polymerization. The dental resin-based materials have high mechanical properties and excellent aesthetic property due to high transparency and have an advantage in operability such that the composition can be cured by light irradiation at the timing intended by the operator in the case of photocurable materials, and therefore it has been widely used in recent years. However, a lot of dental resin-based materials have no self-adhesive property to tooth substances, and when these materials are used, it is necessary to use a dental primer and/or a dental bonding material simultaneously therefore the operation is complicated. Further, if moisture remains on the tooth surface, the penetrability to the tooth substance and the curability of the dental primer and/or the dental bonding material are significantly reduced, therefore moisture-proofing is important in applying them. Therefore, in a clinical case where it is difficult to prevent moisture, a risk by adhesive failure caused by the influence of moisture has been concerned. Furthermore, the pre-protective effect of the second caries by sustained release of a fluoride ion is recognized in only some commercial products.

In contrast, a dental glass ionomer cement represented by a dental glass ionomer cement for filling and a dental glass ionomer cement for luting generally includes polycarboxylic acid, water and acid reactive glass powder represented by fluoroaluminosilicate glass as a main component, and is cured by an acid-base reaction of the polycarboxylic acid and the acid-reactive glass powder. The dental glass ionomer cement exhibits self-adhesive property by action of the polycarboxylic acid in the components. Therefore, one of advantage is that it is not necessary to use a dental bonding material or a dental primer simultaneously. In addition, it is available in a clinical case where it is hard to achieve moisture-proofing, such as root surface caries, because of including water in the components. Further, because a fluoride ion is sustained release from the cured product, the pre-protective effect of the second caries can be expected. On the other hand, the dental glass ionomer cement has lower mechanical properties as compared with the dental resin-based material, and therefore an applicable case is limited to the repair of a portion where stress is hardly applied. In addition, since a dental glass ionomer cement is opaque, the color tone compatibility with a tooth or a dental prosthetic device is low in case of filling the cavity with a dental glass ionomer cement for filling or luting the dental prosthetic device having translucency at the site in which a tooth form was lost by using a dental glass ionomer cement for luting, and therefore there is a problem in aesthetic property. Further, since the setting of the dental glass ionomer cement gradually progresses, the operator cannot perform the next operation, that is, form correction, polishing and removal of the excess cement, for few minutes until the setting progresses to some extent. In addition, the surface may become cloudy when moisture comes in contact with at the initial stage of curing.

On the other hand, in order to compensate for the respective disadvantage of the dental resin-based material and the dental glass ionomer cement, a dental resin-reinforced glass ionomer cement which can be set by multiple mechanisms including photopolymerization and/or chemical polymerization, and acid-base reaction by combining the component composition of the dental resin-based material and the component composition of the dental glass ionomer cement, has been proposed.

For example, Japanese Unexamined Patent Application Publication No. H01-308855 A discloses a dental resin-reinforced glass ionomer cement composition which can be set by both mechanism of photopolymerization and acid-base reaction by containing polycarboxylic acid having a polymerizable group, an acid-reactive powder (fluoroaluminosilicate glass powder or the like), water, a polymerizable monomer (2-hydroxyethyl methacrylate or the like), and a photopolymerization initiator.

Japanese Patent No. 3288698 B discloses a dental resin-reinforced glass ionomer cement composition which can be set by three kinds of mechanisms including photopolymerization, chemical polymerization, and acid-base reaction by containing polycarboxylic acid, an acid-reactive powder, water, a (meth)acrylate-based polymerizable monomer, and a photopolymerization initiator and a chemical polymerization initiator as a polymerization initiator.

Further, in Japanese Unexamined Patent Application Publication No. 2014-152179 A, a dental resin-reinforced glass ionomer cement composition in which the adhesive property to the tooth substance is improved by further adding a polymerizable monomer having an acidic group is proposed.

The above-mentioned dental resin-reinforced glass ionomer cement composition has the advantages of both the dental glass ionomer cement and the dental resin-based material, and has a long-term fluoride sustained release ability and transparency that exceeds conventional dental glass ionomer cements. Further, when the photocurability is imparted, because the composition can be set at the timing intended by the operator by irradiation with light, unlike the conventional dental glass ionomer cement, there is an advantage that there is no need to wait for setting and the like. Furthermore, since the curability of the polymerizable monomer is imparted by radical polymerization, the cloudiness of the surface due to the contact of water at the initial stage of setting, which was a problem of the conventional dental glass ionomer cement that is set only by acid-base reaction, is relatively unlikely to occur.

However, since the dental resin-reinforced glass ionomer cement composition contains water that does not contribute to polymerization and curing, the curability of the polymerizable monomer due to radical polymerization is low, and the curability is still insufficient on the surface that is further affected by polymerization inhibition by oxygen. Therefore, the set product of the dental resin-reinforced glass ionomer cement composition has been easily colored. Further, since the dental resin-reinforced glass ionomer cement composition contains a hydrophilic polymerizable monomer as a main component in consideration of the compatibility with water contained in the composition, the set product has a large water absorption amount which is associated with the above-mentioned low polymerization-curability, therefore the water absorption expansion tended to increase. Furthermore, further improvement has been demanded for the cloudiness of the surface due to the contact of moisture at the initial stage of curing.

In addition, since the liquid material of the dental resin-reinforced glass ionomer cement composition containing polycarboxylic acid and water has a low pH, the coexisting polymerizable monomer is hydrolyzed to cause various problems. Specifically, when a (meth)acrylate-based polymerizable monomer most used in dental materials is used as a polymerizable monomer, the ester bond of the (meth)acrylate group is hydrolyzed and methacrylic acid or acrylic acid, which has high polymerization activity, is generated. Therefore, there is a problem in storage stability such that the liquid material gels during storage and the mechanical properties of the set product deteriorate. This tendency is particularly remarkable when the liquid material contains a polymerizable monomer having an acidic group.

On the other hand, a technique of applying a (meth)acrylamide-based polymerizable monomer that is hard to hydrolysis to various dental materials is disclosed.

For example, Japanese Patent No. 4171600 B discloses a technique for obtaining various dental materials which is hard to hydrolysis and has excellent storage stability even in the presence of an acidic group-containing polymerizable monomer, by applying a di to penta functional (meth)acrylamide-based polymerizable monomer. However, the effects obtained in case that the (meth)acrylamide-based polymerizable monomer is applied to a dental resin-reinforced glass ionomer cement composition are not suggested in this patent document, except for improvement in storage stability. In addition, there is no indication about the structure or the number of functional groups of the (meth)acrylamide-based polymerizable monomer suitable for application to dental resin-reinforced glass ionomer cement composition.

SUMMARY OF THE INVENTION

Technical Problem

In the conventional dental resin-reinforced glass ionomer cements, the surface of the set product is less likely to become cloudy due to contact with moisture at the initial stage of setting, by applying photo-polymerization and/or chemical polymerization. However, it cannot be said that it has been sufficiently improved, and further improvement in surface curability has been demanded. In addition, since the water absorption expansion of the set product is large, the lift of the restoration causes the patient to feel uncomfortable, and in some cases, there is a risk that the dental occlusion with the pairing tooth deteriorates. Furthermore, the property of being easily colored has not been improved yet, and the repair site could not be aesthetically maintained for a long period of time. Therefore, an object of the present invention is to provide a dental resin-reinforced glass ionomer cement composition which maintains the excellent properties of the conventional dental resin-reinforced glass ionomer cement composition, further improves the surface curability shows a small water absorption expansion and excellent coloring resistance, further stably expresses various properties for a long period and is excellent in storage stability.

Solution to Problem

As a result of intensive studies to solve the above problems, the present inventors have found that the curability of the polymerizable monomer in the coexistence of water is dramatically improved, therefore an excellent surface curability is exhibited, the surface of the set product is less likely to be colored, and the water-absorption expansion is reduced, by simultaneously compounding a tri or more functional (meth)acrylamide-based polymerizable monomer together with a (meth)acrylate-based polymerizable monomer having a hydroxyl group as a polymerizable monomer in the basic components of conventional dental resin-reinforced glass ionomer cements, that is, an acid-reactive glass powder represented by fluoroaluminosilicate glass powder, water, a polymer of an acidic group-containing polymerizable monomer represented by polyacrylic acid, a polymerizable monomer, and a polymerization initiator. Further, the present inventors have found that by compounding a tri or more functional (meth)acrylamide-based polymerizable monomer, the storage stability of the liquid material is improved, and therefore excellent storage stability is exhibited in case of compounding an acidic group-containing polymerizable monomer in order to improve the adhesive property to the tooth substance. Further, the present inventors have found that the surface curability and the coloring resistance are further improved and the water absorption expansion is further reduced in case of containing both a mono functional (meth)acrylate-based polymerization monomer that has a hydroxyl group and a bi to tetra functional (meth)acrylate-based polymerizable monomer that has hydroxyl group as the (meth)acrylate-based polymerizable monomer having a hydroxyl group in a specific ratio and/or in case of compounding a tetra or more functional (meth)acrylamide-based polymerizable monomer as the tri or more functional (meth)acrylamide-based polymerizable monomer, and the present invention has been completed.

That is, the above problems are solved by the dental resin-reinforced glass ionomer cement composition of the present invention consisting of a powder material and a liquid material, wherein the powder material contains (a) acid-reactive glass powder, the liquid material contains (b) water, (c) polymer of acidic group-containing polymerizable monomer, (d) hydroxyl group-containing (meth)acrylate-based polymerizable monomer and (e) tri or more functional (meth)acrylamide-based polymerizable monomer, and at least one of the powder material and the liquid material contains (f) polymerization initiator.

It is preferable that at least one of the powder material and the liquid material contains (g) acidic group-containing polymerizable monomer.

It is preferable that the (c) polymer of acidic group-containing polymerizable monomer is a polymer of an α,β-unsaturated carboxylic acid.

It is preferable that the (d) hydroxyl group-containing (meth)acrylate-based polymerizable monomer contains both a mono functional (meth)acrylate-based polymerization monomer that has a hydroxyl group and a bi to tetra functional (meth)acrylate-based polymerizable monomer that has hydroxyl group and the compounding ratio of the mono functional (meth)acrylate-based polymerization monomer that has a hydroxyl group and the bi to tetra functional (meth)acrylate-based polymerizable monomer that has hydroxyl group is 1:2 to 4:1 by weight.

It is preferable that the (e) tri or more functional (meth)acrylamide-based polymerizable monomer is a tetra or more functional (meth)acrylamide-based polymerizable monomer.

It is preferable that the (e) tri or more functional (meth)acrylamide-based polymerizable monomer is a compound represented by formula (1).



(In formula, R1represents a hydrogen atom or a methyl group and R1s may be the same or different from each other, and R2represents a linear or branched alkylene group having 2 to 6 carbon atoms which may have a substituent and R2s may be the same or different from each other.)

It is preferable that all R1s in the formula (1) are hydrogen atom.

It is preferable that the (e) tri or more functional (meth)acrylamide-based polymerizable monomer is a compound represented by formula (2).



(In formula, R1represents a hydrogen atom or a methyl group and R1s may be the same or different from each other.)

It is preferable that all R1s in the formula (2) are hydrogen atom.

Advantageous Effects of Invention

The dental resin-reinforced glass ionomer cement composition of the present invention exhibits high surface curability even under wet conditions. As a result, even in a clinical case where it is difficult to remove water, clouding of the surface due to poor curing hardly occurs. Further, since the set product exhibits excellent mechanical properties and coloring resistance, the initial restoration state can be maintained for a long period of time. Furthermore, since the water absorption expansion is small, discomfort at the time of occlusion due to floating of the restoration is less likely to occur. In addition to these, since these are also excellent in storage stability their characteristics can be stably exhibited for a long period of time.

