Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1999-02-09
2001-02-20
Medley, Margaret (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C523S116000, C523S118000, C522S064000, C522S026000, C522S028000, C522S182000
Reexamination Certificate
active
06191191
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a novel polymerizable composition for dental use, being polymerizable by any method of photo-polymerization and chemical polymerization, having less color change between prior to and after polymerization, generating cured products with great color stability and having good surface curability and a short polymerization time.
Taking advantages of the great characteristic properties of the polymerizable composition for dental use in accordance with the present invention, the composition can effectively be used as an adhesive, a bonding agent, a composite resin, a surface treating agent, an opaque primer and the like, for dental use.
TECHNICAL BACKGROUND
In recent years, polymerizable resin materials have been used as polymerizable compositions for dental use, widely in the entire fields of dental treatment, owing to the great processability such that the materials can appropriately be molded into desired shapes, the good aesthetic beauty such that the materials can restore damaged tooth as if the resulting tooth were natural, and the high strength of the cured product.
Since U.S. Pat. No. 3,066,112 issued in 1959 proposes the application of polyfunctional acrylic polymerizable resins to the treatment of caries, a great number of materials chemically polymerizable at ambient temperature have been put to practical use. Thereafter, a dental material of ultraviolet polymerization has been proposed by using benzoin methyl ether and similar catalysts, in parallel to the progress of materials of chemical polymerization (Japanese Patent Application Laid-Open No. 47-247).
Furthermore, a number of products have been developed, wherein a variety of polymerization processes have been applied, including a dental material of photo-polymerization using camphorquinone (Japanese Patent Application Laid-Open No. 48-49875).
Since then, photo-polymerizable materials containing camphorquinone have widely been used as filling materials for dental use.
For applications where no effective level of light is incident even after photo-irradiation, for example for bonding of metal crowns, inlay and onlay, furthermore, dental materials of chemical polymerization are currently used.
Additionally, Japanese Patent Application Laid-Open No. 60-32810 discloses a dental composition containing a catalyst system comprising one of &agr;-diketone compounds, namely camphorquinone, an organic peroxide and an amine, and describes that the thickness of the resulting unpolymerized layer on the surface is small.
Further, Japanese Patent Application Laid-Open No. 60-89407 describes that a dental composition containing a catalyst system of the same composition as described above can attain very large curing depth.
These compositions for dental use, which contain a catalyst system comprising camphorquinone, organic peroxides and amines, have both the functions of chemical polymerization and photo-polymerization. Such composition shave been used widely as adhesives and bonding agents for dental use, since the compositions have got good appraisal such that the compositions can readily promote high polymerization degree on the surfaces of materials owing to the function of photo-polymerization and can also progress chemical polymerization even in depth where no sufficient light required for polymerization can reach.
However, camphorquinone itself has a color in vivid yellow, polymerizable compositions containing camphorquinone are colored yellow inappropriate for dental materials. Additionally, the vivid yellow of the polymerizable compositions containing camphorquinone fades through photo-irradiation, so that the color changes markedly between prior to and after polymerization. In recent years, the demand for aesthetic beauty from dental patients has been emphasized in the field of dental treatment, and it is said that the vivid yellow color and the color change between prior to and after polymerization are not suitable.
A combination of benzoyl peroxide, i.e. a polymerization initiator, and reducing agents such as tertiary amine, which has been used widely for chemically polymerizable compositions, is problematic in view of color stability in that the color of the cured products of such compositions readily changes when the products are exposed to hot water.
For the purpose of overcoming the problems, a dental composition containing acylphosphine oxide as a photo-polymerization initiator has been proposed (Japanese Patent Publication No. 6-55654). The cured products resulted from the photo-polymerizable compositions containing acylphosphine oxide as a photo-polymerization initiator are excellent in its color stability, but the photo-polymerizable compositions are disadvantageous in that polymerization is not sufficiently facilitated in depth because the curing depth of the composition is shallower than that of the polymerizable compositions containing camphorquinone.
A technique for improving the affinity between teeth and such cured products thereby increasing the adhesion strength between teeth and the cured products, by using an acidic monomer having an acid group together with a polymerizable unsaturated group for a part of polymerizable monomers to be used in dental materials, has been on the way of practical use. Though polymerizable compositions containing acidic monomers have such an advantage as stated above, the thickness of the resulting unpolymerized layer is so large that the hardness of the resulting cured product may be insufficient.
Because the burden over patients is less as the therapeutic treatment time is shorter, a dental material with such a high polymerization rate that can be cured for a short period has been expected.
Therefore, it is an object of the present invention to provide a polymerizable composition for dental use, the composition being colored suitable as a dental material, having less color change between prior to and after polymerization (prior to and after curing) and such a larger curing depth to produce cured products with sufficient hardness and strength even in depth.
Furthermore, it is the other object of the present invention to provide a polymerizable composition for dental use, in addition to the properties described above, being capable of producing cured products with such a small thickness of the unpolymerized layer on the surface and a higher hardness, having a larger polymerization rate so the composition can be cured for a short period of time, and having great adhesion to the teeth.
DISCLOSURE OF THE INVENTION
To attain the objects, the present inventors have made intensive investigations. Consequently, the inventors have found that the use of acylphosphine oxide as a photo-polymerization initiator, an organic peroxide as a chemical polymerization initiator, reducing agents such as the combination of tertiary amine and aromatic sulfinic acid and/or a salt thereof for a polymerizable composition containing a monomer with a polymerizable olefinic unsaturated group can impart excellent curability to the resulting polymerizable composition through any of photo-polymerization and chemical polymerization, which can further have suitable color for dental use, less color change between prior to and after polymerization (prior to and after curing) and great light resistance with less fading.
The present inventors have further found that cured products made from the polymerizable composition have a small thickness of the unpolymerized layer on the surface, a higher hardness; that the polymerizable composition has such large curing depth to produce cured products with sufficient hardness and strength even in depth; and that the composition has so excellent resistance to discoloration by hot water in darkness that the resulting cured products are hardly discolored even if the products are exposed to hot water in the oral cavity.
Still additionally, the present inventors have found that the polymerizable composition containing a monomer with an acid group together with a polymerizable olefinic unsaturated group, as a part of the polymerizab
Harada Miho
Hino Ken-ichi
Kuraray Co. Ltd.
Medley Margaret
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
LandOfFree
Polymerizable dental composition does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Polymerizable dental composition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Polymerizable dental composition will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2594331