JPS6236042A - Cao-al2o3-p2o5 three-component crystallized glass - Google Patents

Abstract

PURPOSE:To lower the temp. in melting, to prevent the evaporation of the contained phosphoric acid component and to obtain the titled glass capable of sufficiently exhibiting the effects due to the content of F by incorporating an F atom into a CaO-Al2O3-P2O5 three-component composition. CONSTITUTION:The titled glass is obtained by incorporating <=3pts.wt. F as an atom into 100pts.wt. CaO-Al2O3-P2O5 material consisting of 10-60wt% CaO, 5-35wt% Al2O3 and 25-85wt% P2O5. The temp. in melting can be lowered due to the content of F, the evaporation of the contained phosphoric acid component is prevented, the molten material is easy to clear, the melting time is reduced, the formation of crystal nuclei is promoted and the advantage of contributing to the improvement of the strength of the product can also be attained.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is directed to the use of Ca0-Al2O2-Pz containing calcium phosphate crystals, which is used as a dental material, artificial bone material, etc.
This invention relates to an Os three-component crystallized glass medical material.

[Conventional technology]

In recent years, the range of applications for ceramics has expanded rapidly, reaching the medical field, and attempts are being made to apply ceramics to medical materials, such as artificial tooth roots, for which metals and plastics have traditionally been used. .

The present inventors searched for a ceramic material that has an affinity for living organisms, and as a result of repeated research into a method for manufacturing high-strength ceramic by freely and highly precisely molding it into any shape, they found that a calcium phosphate-based material was used as a raw material. We have discovered that this is possible by selecting the appropriate method, and have been conducting extensive research on it.

Even with calcium phosphate materials that have these excellent characteristics, once they are vitrified and crystallized, internal defects occur due to the difference in specific gravity between the glass and the crystals, resulting in a decrease in mechanical strength and the infiltration of bacteria. It becomes easier.

For example, the atomic ratio of calcium and phosphorus, Ca/P, is 0.
．． The specific gravity of No. 48 calcium phosphate glass is 2.63, and when it is heat-treated and crystallized, CaO.p2o is generated. The true specific gravity of this Ca0-PzOs crystal is 2.8
5, which is considerably larger than the specific gravity of glass. However, since crystallization proceeds by a surface devitrification mechanism, there is almost no volume reduction accompanying crystallization, and as the specific gravity increases due to crystallization, voids corresponding to the increase in specific gravity are generated inside the crystal, causing cracks. or internal defects such as bores. Because of these internal defects, the strength of the crystal is lower than that of a crystal without defects. Furthermore, since the appearance of bores and the like depends on various factors such as the atomic ratio of calcium and phosphorus in the glass, crystallization temperature, and crystallization time, it is inevitable that the mechanical strength will vary widely.

Even when crystallization is performed by the bulk crystallization mechanism, which involves adding additives or devising the crystallization method, the volume shrinkage during crystallization is larger than that by the surface devitrification mechanism, so the internal defects are Although the degree of occurrence is small, it still occurs in the same way.

In order to eliminate the above-mentioned drawbacks, it is sufficient to eliminate the difference in specific gravity before and after crystallization, and the present inventors have developed a method that does not impair the biocompatibility of calcium phosphate and the characteristics of no volume contraction during crystallization. As a result of various studies on methods that do not cause internal defects, we succeeded in solving the above problem by employing CaO-Al2O3-P205 ternary crystallized glass.

[Problem that the invention seeks to solve]

However, in order to reduce the difference in specific gravity before and after crystallization, a certain amount of Al203m is required, but as the amount of Al2O3 increases, the melting point gradually rises, and in order to completely melt the added Al2O3, You'll have to heat it up quite a bit.

However, when the temperature is raised for melting, the evaporation of the phosphoric acid component becomes significant, which is a disadvantage.

[Means for solving problems]

The present inventors have discovered that the above-mentioned difficulties can be overcome by incorporating fluorine atoms into the composition of the CaOAl2O3P2O6 3-component system, and have completed the present invention.

[Effect]

The features of the present invention are Cao 10~60% by weight, Al2O35
CaO-Al2O3-P2O6 3-component material 10 with a composition range of ~35% by weight and P20s 25-85% by weight
The purpose is to contain 3 parts by weight or less as F atoms per 0 parts by weight.

When a CaO-Al2O3-P2O6 three-component glass with the above composition is crystallized, the crystals produced are mainly Ca0-P.
2O6 and 2CaO・P2O6 and Al2O3・P2
It is O6. Their true specific gravity is 2.85.3.
09, and 2.59, and Al2O3・P2
The specific gravity of O6 is considerably lower than the other two types of calcium phosphate crystals.

For example, the specific gravity of a glass with a composition of 21.8% by weight of Ca, 9.3% by weight of Al2O3, and 68.9% by weight of P2O1 is 2.64, and when this glass is crystallized, the crystals produced are If only the seed calcium phosphate is used, the specific gravity of the crystal is greater than the specific gravity of the glass, causing volumetric contraction and distortion of the external shape, or, if there is no volumetric contraction, defects such as bores will occur inside the crystallization. However, since Al2O3 is included in the glass, Al2 has a low specific gravity.
Since O3 and P2O6 are generated at the same time, their body M expansion compensates for the volumetric contraction caused by calcium phosphate, and the specific gravity after crystallization is 2.67, and the specific gravity difference is approximately 1.
%, internal defects are reduced to an almost negligible level.

However, depending on the range of the CaO/P2O5 molar ratio, it may be necessary to increase the amount of Al2O3 in order to eliminate the difference in specific gravity before and after crystallization of the glass. However, Al
As the amount of 2O3 increases, the melting point gradually increases, and in order to completely melt the added Al2O3, a considerably high temperature is required. However, when the temperature is raised for melting, the evaporation of the phosphoric acid component becomes significant, which is a disadvantage. So CaO-Al2O3
- When F atoms are contained in the P20B three-component material.

This makes it possible to melt Al2O3 at lower temperatures.

Note that the F contained remains in the glass during crystallization and does not affect the difference in specific gravity before and after crystallization. Of course Al2O3
In the region where the amount is not so large, it is desirable to contain F atoms because the inclusion of F atoms helps in melting the sample.

In addition, the inclusion of F atoms makes it easier to clarify the molten raw material, shortens the melting time, and also has the effect of promoting the formation of crystal nuclei during glass crystallization, which improves the strength of the product. It also has the advantage of contributing.

[Hatsumoe composition]

The starting materials of the present invention are calcium-containing compounds such as calcium oxide, calcium hydroxide, calcium carbonate, and calcium oxalate that produce CaO upon calcination, and phosphorus-containing compounds that produce phosphorus oxides upon calcination, such as phosphoric acid and polyphosphoric acid. Compounds, alumina, aluminum hydroxide, and other aluminum-containing compounds that become aluminum oxide when fired are used. Calcium phosphate, apatites, aluminum phosphate, calcium aluminate, etc. can also be used. Also, as a fluorine source, "C" is fluorine. Calcium chloride, aluminum fluoride, fluorine-containing apatite, etc. can be used, but calcium fluoride, which does not sublimate, is the most suitable.

One or more compounds containing calcium, phosphorus, aluminum, and fluorine are selected, and the composition of the glass is set to CaO10~60fUffi%, Al2O35~35%.
% by weight, P is in the range of 20,625 to 85% by weight, and F is adjusted to be 3 parts by weight or less per 100 parts by weight of the total amount of CaO1Al2O3 and P2O6.

If Ca0 is 60% by weight or more or P2O is less than 25% by weight, the melting temperature becomes high and vitrification does not occur. On the contrary, C
If a0 is less than 10% by weight or P is more than 20,685% by weight, the melting temperature decreases and vitrification becomes easy, but crystallization becomes difficult and excess phosphoric acid is liberated, resulting in chemical instability, which is not preferable. On the other hand, if the alumina content exceeds 35% by weight, the melting temperature will increase, and if it is less than 5% by weight, Al2O3/P2O6 crystals will not form or will be formed in small amounts, and the occurrence of internal defects such as bores cannot be prevented. , which is also not desirable. Further, if the F content is 3 parts by weight or more, CaF2 crystals will precipitate, and the specific gravity of these crystals will be large, so that the effect of Al2O3 will be lost, which is not preferable.

The calcium phosphate glass of the present invention basically consists of Ca,
It is composed of three components, AI and P, but when using the crystallized glass produced by the method of the present invention as a dental crown material, a colorant component is added to give it the same color as a natural tooth. You can also do that. When adding a colorant component, 7r rt r Fe + Mn, W, Ce,
It is preferable to use one kind or two or more kinds selected from the oxides of Ti, Ni, Co, Cr, and V, and particularly to use two or more kinds in combination. The amount added is
The content of CaO-Al2O3-P2O63 is 0,01 to 15 parts by weight.

The raw materials are weighed, mixed well, placed in a container, heated to 900'C or higher, preferably 1000 to 1700'C, and melted. Care must be taken when melting, as phosphorus components begin to evaporate when the temperature reaches 18006C or higher.

After the melting is completed, it is cooled and vitrified. Subsequently, it is melted and cast again, but the first melt may be directly cast without being cooled and vitrified. CaO-Al2O3- of the present invention
In the case of P2O6 ternary materials, the lost wax process, which is carried out on metallic dental materials, is suitable for casting. The preheating temperature of the casting mold is suitably selected within the range of 800°C or less, preferably from 200 to 800'C, depending on the material and glass composition of the casting mold.

The casting thus cast is glassy. By subjecting this glassy material to appropriate heat treatment to make it crystallized at °C, the properties can be further improved. The method for crystallizing the three-component crystallized glass according to the present invention is as follows. A molded body formed by a lost wax method or the like is usually heated in a suitable heating device such as an immersion mold or an electric furnace. The heating temperature at this time is below the melting point, preferably 600 to 1100°C.

〔Example〕

Example 1 Calcium carbonate powder, alumina powder, orthophosphoric acid, and calcium fluoride powder with a final composition of CaO 13, 6% by weight
, A 120 3 28.0% by weight, P 20 G
58.4% by weight, CaO+Al2O3+P+Oa 1
Weigh out so that F is 1.5 parts by weight based on 0 parts by weight, mix well, and then heat at 130°C to remove moisture.
Next, it was melted at 1,600''C for Ihr, and the connecting tooth crown was pressure cast into an embedded mold, and cooled and vitrified.The obtained glass was held in an electric furnace at 750°C for 5 hours as an embedded mold to crystallize it. It became.

The obtained product was white and translucent, and as a result of X-ray diffraction of the crystal, CaO・p2os and Al2O3・P were found in the crystal.
2O5 was present. Also, the specific gravity of both glass and crystal is 2.
．． 66, there was no difference in specific gravity, and when the microstructure of the crystal was observed under a microscope, no internal defects such as bores were found.

Comparative Example 1 An attempt was made to melt the material in the same manner as in Example 1 except that it did not contain calcium fluoride, but the raw material did not melt completely at 1600°C, so it finally melted when the temperature was raised to 1850°C, but the melt While heating was continued until it became clear, the phosphoric acid component evaporated and crystals gradually began to precipitate.

〔Effect of the invention〕

As seen in the examples and comparative examples, the CaO of the present invention
In the case of -Al2O3-P20B crystallized glass containing F, the temperature during melting could be lowered, and the effect of containing F was fully exhibited.

Claims (1)

[Claims] CaO 10-60% by weight, Al_2O_3 5-35
Ca consisting of 25-85% by weight of P_2O_6
A CaO-Al_2O_3-P_2O_6 ternary crystallized glass, characterized in that it contains 3 parts by weight or less of F atoms based on 100 parts by weight of the O-Al_2O_3-P_2O_6-based material.