Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2001-09-10
2003-11-04
Yoon, Tae H. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C523S113000, C523S116000, C523S118000, C524S321000, C522S079000
Reexamination Certificate
active
06642286
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a resin composition for soft relining material, that is used for improving the fitness of a denture, or for a mucosal conditioner that is temporarily used until diseases of a patient who mounts a denture, such as atrophy or inflammation in an oral mucosa, have been cured, in the dental remedy.
2. Description of the Conventional Art
In the dentistry, when a denture is used for a long period of time, the fitness between a denture base and an oral mucosa becomes worse due to absorption of an alveolar ridge and the like, whereby it becomes poor to maintain and stabilize the denture. In such case, it is generally attempted to recover the fitness between the denture base and the oral mucosa by a treatment in which one layer of the oral mucosa side of the denture base is eliminated, and a resin material for soft relining material is laminated thereon. This soft relining material is a relatively soft and functions to compensate a lost elasticity of an alvelar ridge mucosa and to impart cushioning properties, thereby lessening the impact during occlusion. As such soft relining materials, has been widely used a resin composition for denture base, which comprises a powder of a polymer such as polymethyl methacrylate and a liquid of a monomer such as methyl methacrylate, containing about 10 to 90% by weight of a phthalate-based plasticizer.
In addition, when the patient continues to use the denture in an unfit state, since a non-uniform force is continuously applied to the mucosa under the denture base, atrophy or inflammation occurs in the oral mucosa, resulting in a pain during the occlusion. In such case, relining must be carried out after the oral mucosa has become in a healthy state, or depending on the case, a new denture must be prepared. During this time, it is attempted to protect and recover the oral mucosa by laminating a soft material for denture base called a mucosal conditioner on the oral mucosa side of the denture base. As such mucosal conditioners, has been widely used a resin composition for soft relining material, which generally comprises a powder of a polymer such as polymethyl methacrylate and a liquid of a phthalate-based plasticizer containing about 8 to 20% by weight of ethanol.
As described above, the phthalate-based plasticizers are widely used as a component for softening a cured material in resin compositions for soft relining material, such as mucosal conditioners. However, in recent years, it has begun to be pointed out that the phthalate-based plasticizers may possibly influence living bodies as an endocrine disrupter, and the development of a resin composition for soft relining material is being proceeded to a direction that the use of substances possibly influencing living bodies be avoided as far as possible. For these reasons, it has been demanded to develop a soft resin composition for relining material such as a mucosal conditioner, using a substitute for the phthalates.
SUMMARY OF THE INVENTION
Thus, the present invention is aimed to provide a resin composition for soft relining material that can meet the performances required in the conventional art, such as a proper softness and fitness between a denture base and an oral mucosa, without using a phthalate-based plasticizer that has hitherto been widely used in the resin composition for soft relining material.
In order to achieve the above-described aim, we, the present inventors made extensive and intensive investigations. As a result, it has been found that an acid ester-based plasticizer has no possibility to influence living bodies as an endocrine disrupter; a resin composition for soft relining material comprising this acid ester-based plasticizer, a (meth)acrylate monomer having at least one unsaturated double bond, a polymerization initiator, and a (meth)acrylate polymer or copolymer, can give various performances same as those in the conventional art resin material for soft relining material; the above-described (meth)acrylate monomer having at least one unsaturated double bond is polymerized to fix the acid ester-based plasticizer and ethyl alcohol in the polymer, thereby preventing the elution of these materials; and the thus formulated resin material for soft relining material can impart an advantage such that it does not become hard with a lapse of time during the use, leading to accomplishment of the invention.
The term “acid ester” as used herein refers to an ester of an aliphatic acid.
Specifically, the present invention is concerned with a resin composition for soft relining material comprising (a) a (meth)acrylate monomer having at least one unsaturated double bond; (b) an acid ester-based plasticizer; (c) a (meth)acrylate polymer or copolymer; and (d) a polymerization initiator. In particular, the present invention is preferably concerned with a resin composition for soft relining material comprising 2 to 50% by weight of the (meth)acrylate monomer (a) having at least one unsaturated double bond; 20 to 80% by weight of the acid ester-based plasticizer (b); and 10 to 70% by weight of the (meth)acrylate polymer or copolymer (c); and 0.005 to 5 parts by weight based on 100 parts by weight of the total sum of the components (a), (b) and (c), of the polymerization initiator (d). If desired, the resin composition for soft relining material according to the present invention may further contain 1 to 15% by weight of (e) ethyl alcohol. Further, it is preferred that the acid ester-based plasticizer (b) is at least one plasticizer selected from the group consisting of trimellitic acid esters, fatty acid esters, acetic acid esters, maleic acid esters, fumaric acid esters, and citric acid esters.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The respective components of the resin composition for soft relining material according to the present invention will be described below in detail.
The (meth)acrylate monomer having at least one unsaturated double bond as the component (a) swells the (meth)acrylate polymer or copolymer as the component (c) to impart proper operability to the resin composition for soft relining material. Further, the (meth)acrylate monomer having at least one unsaturated double bond as the component (a) is polymerized by the polymerization initiator as the component (d), thereby functioning to prevent the acid ester-based plasticizer as the component (b) and ethyl alcohol as the component (e), which is compounded, if desired, in the composition from elution out of the composition after the polymerization.
As the (meth)acrylate monomer having at least one unsaturated double bond as the component (a), are usable general monomers that have hitherto been used in the dentistry. Specific examples include monomers of methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxy-1,3-dimethacryloxypropane, t-butyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, butoxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, glycidyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, benzyl (meth)acrylate, ethylene glycol (meth)acrylate, diethylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, and polyoxytetraethylene glycol di(meth)acrylate. These (meth)acrylate monomers having at least one unsaturated double bond can be used singly or in admixture. An amount of the component (a) to be compounded is preferably 2 to 50% by weight in the resin composition for soft relining material. When the amount of the monomer to be compounded is less than 2% by weight, the swelling of the (meth)acrylate polymer or copolymer as the component (c) is insufficient, whereby the operability is deteriorated. On the other hand, when it exceeds 50% by weight, it is difficult to impart a proper elasticity (softness) after curing.
Examples of the aliphatic acid ester-based plasticizer as the component (b) include trimelliti
Kumagai Tomohiro
Nakayama Mizuki
Sekiguchi Toshihiro
GC Corporation
Yoon Tae H.
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