JPH02250811A - Dental cement composition - Google Patents

Abstract

PURPOSE:To provide a dental cement composition having mechanical properties similar to those of natural tooth and excellent bio-compatibility and composed of a specific calcium phosphate mixture and a kneading liquid consisting of an aqueous solution containing a polyacid or lactic acid. CONSTITUTION:The objective dental cement paste is composed of (A) a calcium phosphate mixture containing (a) tetracalcium phosphate powder and (b) dibasic calcium phosphate dihydrate powder and/or dibasic calcium phosphate powder at a molar ratio (a/b) of (1.0-1.3)/1 and (B) a kneading liquid consisting of an aqueous solution containing 20-50wt.% of a polyacid (preferably a copolymer of acrylic acid and itaconic acid) or 10-40wt.% of lactic acid. The cement paste composition completely satisfies the characteristics required as a restorative dental material (heat-conduction resistance, mechanical strength, physical proper ties, aesthetic nature and bio-compatibility) and is applicable without damaging the dental pulp or terminal of nerve caused by the separation of a low-molecular compound.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to cement compositions used in dental treatment.

[Prior Art] A healthy tooth has 1flfIlli inside it. It is well known that dental pulp is sensitive to heat and pressure because it is in contact with nerve endings. Therefore, as a dental restorative material, it is difficult to transmit heat and pressure to the dental pulp, that is, it has excellent heat conduction and mechanical strength, and it also has physical properties such as abrasion resistance, water resistance, and affinity with teeth, that is, adhesiveness. It is important to have both aesthetic properties such as transparency and abrasiveness, and biocompatibility such as no harmful effects on living organisms, in order to make the material look more like a natural tooth.

Conventionally, compositions that produce hydroxyapatite, which is the main component of bones and teeth, after hardening have been proposed as such hardenable materials. For example, a composition comprising a kneading solution of tetracalcium phosphate and/or α-tricalcium phosphate and water or an aqueous organic acid solution is known.

Furthermore, many proposals have been made for dental cement compositions. For example, JP 63-201038 discloses a fluoroaluminosilicate glass powder provided for dental glass ionomer cement;
09 is a dental product consisting of a polymerizable monomer consisting of an acrylate derivative or a methacrylate derivative, a photosensitizer consisting of an α-diketone or quinone derivative that exhibits clear absorption at a wavelength of 380 to 500 nn, and a polymerization accelerator of an amine compound. JP-A No. 63-253011 discloses a dental cement composition comprising a photopolymerizable calcium hydroxide cement; and JP-A No. 63-316709 discloses a photocurable composition that can be easily converted into Φ gold sand by irradiation with visible light. Therefore, we have proposed a photopolymerizable dental prosthetic composition that has high mechanical properties and excellent water resistance.

As a result of intensive research to obtain a curable material with mechanical properties similar to those of natural teeth and excellent biocompatibility, the present inventor discovered tetracalcium phosphate powder and dicalcium phosphate powder.
A calcium phosphate mixture (A) consisting of dihydrate powder and/or dibasic calcium phosphate powder, and a kneading solution (B) consisting of an aqueous solution containing polyacid or lactic acid.
A dental cement composition consisting of It was discovered that there was no damage to the dental pulp or nerve terminals due to the release of the molecular compound, and based on this finding, the present invention was accomplished.

Means for Solving Problem E] The calcium phosphate mixture (A) of the present invention consists of a tetracalcium phosphate powder, a dicalcium phosphate dihydrate powder, and/or a dicalcium phosphate powder.

Use of tetracalcium phosphate powder 1 (a) for ffi of dicalcium phosphate dihydrate powder and/or dicalcium phosphate powder (b) a/b = 1.0-
The ratio is 1.3/1 (molar ratio).

If the amount of tetracalcium phosphate powder used is less than 1.0 mol relative to the amount of dicalcium phosphate dihydrate powder and/or dicalcium phosphate powder, a cured product that does not have the desired mechanical strength may result. It may be produced. When the amount of tetracalcium phosphate powder used exceeds 1.3 mol, the mechanical strength of the cured product tends to decrease.

The particle size of the tetracalcium phosphate powder used in the present invention is 1-
Preferably, the average particle size is 5-10 μm at 20 μI.

If there is a large amount of tetracalcium phosphate powder with a particle size of less than 1 μm, the initial film formation reaction may occur rapidly, resulting in the production of a cured product with reduced mechanical strength. If a large amount of tetracalcium phosphate powder with a particle size exceeding 20 μm is present, voids will be present in the cured product, and the mechanical properties of the cured product will deteriorate.

The particle size of the dibasic calcium phosphate dihydrate powder and dibasic calcium phosphate powder used in the present invention is preferably 0.2-2 μm. If there are a large amount of dicalcium phosphate dihydrate powder and dicalcium phosphate powder with a particle size exceeding 2 μ-, the curing time becomes long, which is not practical.

Hydroxyapatite powder is added to the calcium phosphate mixture of the present invention in a proportion of not more than 51i% by weight, and/or 1% by weight.
Sodium fluoride can also be added in the following proportions.

The hydroxyapatite powder used in the present invention has a particle size of 0.
05-5 μm is preferred.

The hydroxyapatite powder to be mixed acts as an accelerator for the hydroxyapatite reaction between tetracalcium phosphate and dicalcium phosphate dihydrate and/or dicalcium phosphate, and also acts as a seed to form bitroxyapatite crystals produced by the reaction. The production of is promoted. Sodium fluoride also acts as a promoter of the above reaction.

By mixing hydroxyapatite powder, which is a main component of teeth, in the calcium phosphate mixture, the hydroxyapatite formation reaction is accelerated, hydroxyapatite with a desired shape can be produced, and the mechanical properties of the produced cured product are improved. It is preferable to mix hydroxyapatite powder because the filler will be closer to the tooth, the filling will not come off, fall off, or discolor, and the biocompatibility will be even better.

Calcium fluoride can also be mixed into the calcium phosphate mixture of the present invention in a proportion of 5% by weight or less. Calcium fluoride converts generated hydroxyapatite into fluoroapatite, so it is preferable from the viewpoint of preventing dental caries.

As the kneading solution (B) of the present invention, an aqueous solution containing 20-50% by weight of polyacid or an aqueous solution containing 10-40% by weight of lactic acid is used.

If the content of polyacid is less than 201 ffi% and the content of lactic acid is 10% or less, the mechanical properties of the cured product will deteriorate and the curing time will become longer, which is undesirable. The content of acid is 50% by weight and the content of lactic acid is 4% by weight.
If it exceeds 0%, the curing time will be too short to be practical, and the biocompatibility may deteriorate.

The lactic acid aqueous solution can also contain 10% by weight or less of glycolic acid.

The polyacid contained in the kneading solution (B) of the present invention is a copolymer of acrylic acid and itaconic acid, and has a molecular weight of s, ooo
~30,000, preferably 10,000-17,00
0 is used.

Calcium phosphate mixture (A) and kneading liquid (B) of the present invention
Just before use, knead it on a tray. The mixing ratio is not particularly limited. Root canal filling material, lining material,
Mix as desired according to the intended use of the restorative material, such as WI leather material, periodontal pocket filling material, and tooth extraction filling material. In general, powdering may be adjusted so that the resulting paste has a viscosity of 1 to 1000 voids, for example, powder component (A) kneading solution (
An example may be a mixing ratio of 1-5/1 (vertical hanging ratio) for B).

If necessary, other components may be added to the calcium phosphate mixture (A) of the present invention within a range that does not significantly adversely affect the curability. For example, in order to provide X-ray contrast properties, 5 to 50 parts by weight of barium sulfate, barium glass, strontium glass, zirconia, iodoform, etc. can be added to 100 suspended parts of the calcium phosphate mixture (A).

[Effect] Calcium phosphate mixture (A) of the present invention and kneading liquid +8)
The cured product has almost the same mechanical properties as teeth, namely mechanical strength, heat resistance, conductivity, abrasion resistance, water resistance,
It has excellent affinity with teeth, that is, adhesive properties, and has excellent adhesion to tooth structure without the need for etching or bonding treatment, and is also biocompatible, such as having no harmful effects on the entire body. be.

Furthermore, the curing time of the cured product consisting of the calcium phosphate mixture (A) and the kneading solution (B) [Gilmore needle test (ANSI/ADA Spc, No. 8>,
Measured at 37°C ± 1°C, RH 100%] is 3-15 minutes, and the diametrical tensile strength of the cured product after 1 day - (37
℃±1℃) is 10 HPa or more, which is sufficient for practical use.

The paste-type restorative material of the present invention can be used not only as a dental restorative material such as a root canal filling material, a backing material, an Il quasi-material, a periodontal pocket filling material, and a filling material for tooth extraction, but also as a bone cement, bone filling material, etc. It can also be widely used as a restorative material for orthopedic surgery.

[Examples] Examples are shown below to further specifically explain the present invention, but the present invention is not limited to these Examples.

Example 1 21.960 finely ground (particle size: 1-20 μI
.

Tetracalcium phosphate (manufactured by Tokuyama Soda Co., Ltd., 5-C4P) with an average particle size of near μm), 8.16 g of finely ground (particle size: 0.2-2 μm) dicalcium phosphate (manufactured by Tokuyama Soda Co., Ltd.) DCPA), 0.879 (particle size 0
．． A calcium phosphate mixture was prepared by mixing 05-2 μl of hydroxyapatite (manufactured by Central Glass Co., Ltd.) and 0.05-2 μl of sodium fluoride.

Copolymer of acrylic acid and itaconic acid Molecular weight: 15
,000) was prepared and used as a kneading solution.

Obtained calcium phosphate mixture (A) and kneading solution (B)
Knead on a tray and mix with stainless steel vI9 (
6MD x 3 Dark H) Niju 1m. After being stored for one day at 37°C ± 1°C, a compressive load was applied at a crosshead speed of 10 μI using a universal testing machine (manufactured by Minebea), and the diametrical tensile strength was 1! ! As a result of measuring (DTS), 11.2
It was 1 HPa.

Curing time Gilmore needle test (ANSI/A
D^Spc, No. 8) 37℃±1℃, R8
As a result of measurement at 100%, it was 7 minutes.

Example 2 Instead of the aqueous copolymer solution of acrylic acid and itaconic acid in Example 1, a lactic acid aqueous solution (lactic acid-containing ffi: 30ffj
A cured product was prepared in the same manner as in Example 1, except that the compound (%) was used as the kneading liquid.

The diametrical tensile strength (DTS>) and curing time of the obtained cured product were 11.19 HPa and 7 minutes, respectively.

Claims (8)

[Claims] (1) A calcium phosphate mixture (A) consisting of tetracalcium phosphate powder, dibasic calcium phosphate dihydrate powder and/or dibasic calcium phosphate powder, and a kneading solution (B) consisting of an aqueous solution containing polyacid or lactic acid.
A dental cement composition consisting of. (2) The dental cement composition according to claim 1, wherein the polyacid is a copolymer of acrylic acid and itaconic acid. (3) The dental cement composition according to claim 1, wherein the kneading liquid (B) is an aqueous solution containing 20-50% by weight of polyacid. (4) The dental cement composition according to claim 1, wherein the kneading liquid (B) is an aqueous solution containing 10-40% by weight of lactic acid. (5) The dental cement composition according to claim 4, wherein the kneading liquid (B) further contains 10% by weight or less of glycolic acid. (6) The mixing ratio (molar ratio) of tetracalcium phosphate powder (a_1) to dibasic calcium phosphate dihydrate powder and/or dibasic calcium phosphate powder (a_2) in the calcium phosphate mixture (A) is a_1/a_2=1 .0-
The dental cement composition according to claim 1, which has a ratio of 1.3/1. (7) The dental cement composition according to claim 1, wherein 5% by weight or less of hydroxyapatite powder and/or 1% by weight or less of sodium fluoride powder are added to the calcium phosphate mixture (A). (8) The dental cement composition according to claim 1, wherein 5% by weight or less of calcium fluoride powder is added to the calcium phosphate mixture (A).