JPH0417905B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a calcium phosphate-based crystallized glass dental material having a color tone equivalent to or very close to that of natural teeth. Here, dental materials refer to materials used as artificial teeth such as crowns, inlays, bridges, etc., as well as tooth roots, implants, etc., and tooth crowns (hereinafter simply referred to as crowns).

[Conventional technology]

Traditionally, resins, metals, porcelain, etc. have been mainly used as dental materials, and ceramic materials are also being considered recently, but all of them have advantages and disadvantages as materials that can be used for a long time in the oral cavity.

Calcium phosphate crystallized glass has been proposed as a material that overcomes the drawbacks of the various materials mentioned above (Japanese Patent Publication No. 11625/1983). This calcium phosphate material is a material that has been attracting attention recently because its composition is mainly composed of phosphorus and calcium, and it has the same composition as natural teeth and has good affinity with the gingival tissue.

[Problem that the invention seeks to solve]

The only drawback of this excellent calcium phosphate crystallized glass is that it is white in color, which is different from natural teeth and is therefore less aesthetically pleasing.

In order to improve this esthetics, the present inventors succeeded in obtaining a color tone close to that of natural teeth by adding a coloring component to the calcium phosphate raw material (Japanese Patent Application No. 58-125164
Because the number of added ingredients was limited to three types, it was not possible to follow the slight differences in color tone that differ slightly from person to person.

[Means for solving problems]

The present inventors further investigated the combination of multi-component coloring agents, and found that Zn, Fe,
By adding 0.01 to 5 parts by weight of four or more components selected from the oxides of Mn, Ce, W, Ti, Ni, Co, Cr, and V to 100 parts by weight of calcium phosphate, it can be customized to individuals. As a result, the present invention has been completed by successfully tracking slight differences in color tone.

[Effect]

The coloring method of the present invention involves adding a coloring component to a calcium phosphate-based material as an additive, and in some cases further adding a coloring aid, melting and vitrifying the material, casting the glass into a dental crown, and then crystallizing it. The color tone of your natural teeth is obtained at this point. In the present invention, the color tone of natural teeth is not developed by the color of additives, but by interaction with the calcium phosphate component of the material, and the color tone is developed only by the mixing, melting, casting, and crystallization steps. The desired color is obtained after the process.

This coloring component is incorporated into the calcium phosphate crystal and is a constituent component of the crystal, so it will not dissolve into saliva or the like during use and will not have a toxic effect on the body.

Moreover, the dental material of the present invention not only exhibits the color tone of natural teeth, but also exhibits the transparency of teeth, and furthermore, the color tone can be subtly adjusted by combining and mixing coloring components, and the ratio of addition to the material. Therefore, when applied to dental materials, it is characterized in that it can cover differences in the color tone of individual teeth and differences in color tone depending on parts such as front teeth and molar teeth.

[Structure of the invention]

The calcium phosphate-based material of the present invention is basically a calcium-containing compound that produces CaO when fired, and a phosphorus-containing compound that produces phosphorous oxides such as P ₂ O ₅ when fired. Examples of calcium-containing compounds that can be used include calcium oxide, calcium hydroxide, calcium carbonate, calcium hydrogen carbonate, basic calcium carbonate, and calcium salts of organic acids such as calcium oxalate and calcium acetate. As the phosphorus-containing compound, polyphosphoric acids such as orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid, triphosphoric acid, trimetaphosphoric acid, and tetrametaphosphoric acid, or ammonium salts of these phosphoric acids are used. Calcium salts of phosphoric acids such as calcium hydrogen phosphate, calcium dihydrogen phosphate, calcium phosphate, calcium pyrophosphate, acidic calcium phosphate, calcium polyphosphates, and hydroxyapatite may also be used alone or in combination with other calcium-containing compounds or phosphorus-containing compounds. It can be used as

The ratio of calcium-containing compounds and phosphorus-containing compounds used is determined by the atomic ratio of calcium to phosphorus, C.
a/P is 0.35 to 1.7. When this atomic ratio exceeds 1.7, the degree of melting becomes extremely high and, moreover, it does not vitrify and devitrification occurs during cooling. When devitrification occurs, coarse crystal grains of calcium phosphate are included in the structure, resulting in a marked decrease in brittleness and poor toughness, which is not preferable.

On the other hand, if the atomic ratio is less than 0.35, the melting temperature will decrease and vitrification will become easier, but the crystallization process described below will take a long time, and excess phosphoric acid will be liberated, resulting in chemical instability. I also don't like it.

The dental material of the present invention contains Zn, Fe, Mn, Ce, W, Ti, Ni, Co, Cr,
Four or more components are selected from compounds containing V, such as oxides, acetates, sulfides, nitrates, carbonates, and ammonium salts of these metals, which can become oxides in the melting process described below. It is characterized by being added with.

If this coloring component is used alone, it is not possible to obtain the color tone of natural teeth. However, although it is possible to obtain a color tone close to that of natural teeth by mixing two or three of these coloring components at a certain ratio, it is not sufficient to obtain a subtle color tone, and only by combining four or more types. The desired color tone can be obtained. The hue changes depending on the combination of coloring components and their component ratio, and the shade of the color changes depending on the addition ratio of the total amount of coloring components.

The total amount of coloring ingredients added is based on the calcium phosphate composition.
Calculated as coloring component oxide per 100 parts by weight
It is 0.01 to 5 parts by weight. If the amount added is less than 0.01 part by weight, the color development will be insufficient and the color will be erased by the white color of the calcium phosphate crystallized glass, while if it exceeds 5 parts by weight, not only will the color develop after crystallization be too dark, but the melting point of the mixture will increase. However, the viscosity of the melt increases, making casting difficult, both of which are undesirable.

In the calcium phosphate-based crystallized glass dental material of the present invention, a color tone close to that of natural teeth can be obtained by adding a coloring component as described above, but in addition, Al ₂ O 3 and Al 2 O ₃ are added as coloring aids. /Or by adding SiO ₂ , aesthetics can be further enhanced.

When adding, in addition to oxides, hydroxides, oxyoxides, ammonium salts, etc., which become oxides when melted, are used. These components act to assist in color development when the coloring component interacts with the calcium phosphate component of the material to develop color. The amount added is converted to oxide, and the calcium phosphate composition is 100%
It is not more than 10 parts by weight. This amount added
If it exceeds 10 parts by weight, the viscosity of the melt increases, making it difficult to cast, which is not preferable.

Al ₂ O ₃ and/or added as coloring aids
Alternatively, in addition to acting as a coloring aid, SiO ₂ acts as a nucleating agent when calcium phosphate crystallizes, and has the effect of suppressing the growth of calcium phosphate crystal grains, producing a large amount of fine crystals. is more preferable.

An example of the method for producing dental materials using the calcium phosphate crystallized glass of the present invention is as follows.

The calcium compound, the phosphorus-containing compound, the coloring component, and if necessary the coloring aid component are each weighed out, and if they are solid, they are pulverized and mixed well. Place this raw material mixture in a suitable container and heat it to over 900℃.
Preferably, it is heated and melted at 1000 to 1600°C.

The melting temperature varies depending on the raw material composition, but within the above-mentioned temperature range, the viscosity of the melt can be kept sufficiently low, making it optimal for casting. When the melting temperature becomes high, particularly above 1700°C, evaporation of the phosphorus component begins, the composition gradually becomes too calcium-rich, and the melting point gradually rises, so care must be taken. This melt is cooled to form a glass. The cooling method is not particularly limited.

The glass-like material thus obtained may be cast into a dental material by any method, such as a centrifugal casting method based on the lost wax method, a compression casting method, a vacuum compression casting method, or the like. The melting temperature at this time is also 900°C or higher, preferably 1000 to 1600°C. The lost wax method is a method used for metal dental materials, but if the calcium phosphate of the present invention has a Ca/P in the range of 0.35 to 1.7, the melting point and viscosity are almost the same as those of the metal material, and it is suitable for casting by the lost wax method.

The material cast by the lost wax method is placed in a mold or taken out from the mold and heated and crystallized in a suitable heating device such as an electric furnace. At this time, the heating rate is 50 to 3000°C/hr, the heating temperature is 500 to 800°C, and the holding time is 0.5 to 100 hr.

Through this crystallization operation, the colored component that interacts with the calcium phosphate component is incorporated into the crystal and stabilized, and at the same time develops a color similar to that of natural teeth.

〔Effect of the invention〕

The dental material made of calcium phosphate-based crystallized glass of the present invention has the following characteristics compared to conventional dental materials.

(1) The dental crown material is a phosphoric acid and calcium based material that has ideal materials and characteristics close to those of natural teeth, and its color tone is closer to that of natural teeth to improve aesthetics.

(2) The color tone can be changed by adjusting the type and amount of coloring components, making it possible to create subtle colors that match individual differences.

(3) The coloring component interacts with the material component to develop color and become insoluble, and since it is incorporated into the crystal, there is no need to worry about it leaching out.

(4) Since the coloring component is added to the raw material, the process is exactly the same as usual, and there is no need for a complicated coloring process such as the porcelain veneer method.

(5) Aesthetics can be further improved by adding a coloring aid.

〔Example〕

The present invention will be specifically explained below using Examples.

Example 1 Calcium carbonate and phosphoric acid are weighed so that the atomic ratio of calcium to phosphorus is Ca/P=0.5. Coloring components: Fe ₂ O ₃ 20% by weight, NiO 20% by weight, CeO ₂ 20
% by weight, 0.5 for 100 parts by weight of TiO ₂ 40% by weight mixed powder converted to calcium phosphate
Add parts by weight.

These mixtures were placed in a platinum crucible and placed in an electric furnace.
The temperature was raised to 1300°C and maintained for 2 hours to melt. This melt was cast into an alumina mold and allowed to cool. The sample at this time was yellowish brown glass. This glass was placed in an electric furnace and the temperature was raised to 680°C at a heating rate of 300°C/hr and maintained for 20 hours to complete crystallization. The color tone after crystallization was a dark ivory color with a slight blackness, which was closer to the color tone of natural teeth than in the comparative example described below.

Example 2 Calcium carbonate and phosphoric acid were taken so that the atomic ratio of phosphorus and calcium was Ca/P = 0.5, and 20% by weight of Fe ₂ O ₃ and NiO were added as coloring components to 100 parts by weight in terms of calcium phosphate. 20% by weight,
Added 0.3 parts by weight of a mixed powder consisting of 30% by weight of MnO ₂ and 30% by weight of TiO ₂ and 1 part by weight of Al ₂ O ₃ as a coloring aid.
Melting, casting, and crystallization were performed under the same conditions as in Example 1. After crystallization, the color was a somewhat yellowish ivory, very similar to natural teeth.

Comparative example 1 Coloring components: NiO 20% by weight, CeO ₂ 40% by weight,
The same method as in Example 1 was used except that 0.5 parts by weight of TiO ₂ 40% by weight mixed powder was added to 100 parts by weight in terms of calcium phosphate, and 1 part by weight of Al ₂ O ₃ was added as a coloring aid. Crystallized glass was obtained. Although the product thus obtained was ivory-colored, Example 1
Compared to 2 and 2, the esthetics were slightly inferior.

Example 3 10% by weight of CeO ₂ and 20% by weight of NiO as coloring components based on 100 parts by weight in terms of calcium phosphate.
TiO ₂ 20% by weight, WO ₃ 20% by weight, MnO ₂ 10% by weight,
0.3 parts by weight of a mixed powder consisting of 20% by weight of Fe ₂ O 3 and 1 part by weight of Al ₂ O ₃ as a coloring aid were added, and melting, casting and crystallization _were carried out under the same conditions as in Example 1.

The color tone at this time was an ivory color with a very slight bluish tint, and the aesthetics were further improved.

Claims (1)

[Claims] 1 The atomic ratio of calcium to phosphorus is 0.35~
For 100 parts by weight of calcium phosphate composition of 1.7,
Coloring components include Zn, Fe, Mn, Ce, W, Ti, Ni,
0.01 to 5 parts by weight of four or more components selected from oxides of Co, Cr, and V, and if necessary, 10 parts of Al ₂ O ₃ and/or SiO ₂ as a coloring aid.
A calcium phosphate crystallized glass dental material with superior aesthetics, characterized by containing less than 1 part by weight.