JPH0421621B2 - - Google Patents

Description

[Detailed description of the invention]

(Technical Field) The present invention relates to a calcium phosphate crystalline glass with improved durability. (Prior art and its problems) As dental materials such as dentures, tooth roots, crowns, inlays, and bridges, and biomedical ceramic materials such as surgical artificial bone materials, for example, Japanese Patent Publication No. 11625/1983 discloses CaO 28 to 57 wt. %, P ₂ O ₅ 72-43 wt % glass, or this with 10 wt % or less Al ₂ O ₃ ,
Calcium phosphate-based crystallized glass has been proposed, which is obtained by melting glass to which SiO ₂ or B ₂ O ₃ is added, molding and heat-treating the glass to crystallize it to a degree of crystallinity of 20% or more. This calcium phosphate crystallized glass has a composition very similar to that of natural teeth or natural aggregates, and its physical, chemical, and mechanical properties are also close to those of natural teeth or natural aggregates, and it is compatible with living organisms. Moreover, it can be manufactured using a simple process of melting the raw material powder into a glass shape, pouring it into a mold, and then crystallizing it.Furthermore, the shrinkage rate during the manufacturing process is only 1%, making it easy to manufacture without complicated processes. Since precision machining is not required for the shape, dental materials,
Ceramic materials for biomedical applications such as surgical artificial aggregates are expected to have superior properties and high mass productivity compared to conventional metal materials and ceramic materials. However, the atomic ratio between calcium and phosphorus
To improve the water resistance of calcium phosphate crystallized glass with Ca/P in the range of 0.5 to 1.7.
Although the water resistance and initial strength of the products to which Al ₂ O ₃ was added were improved, it was found that the initial strength was still insufficient and the product often broke during use. (Objective and Summary of the Invention) The present invention was invented as a result of research for the purpose of improving the above-mentioned drawbacks, and the gist thereof is that the atomic ratio Ca/P of calcium and phosphorus is 0.5 to 0.7. For calcium phosphate crystalline glass
The present invention relates to a calcium phosphate-based crystalline glass for biological use, which contains 0.5 to 5 mol% of Al ₂ O ₃ and 0.05 to 0.5 mol % of R ₂ O (R represents Na, K, or Li). (Structure of the Invention) The present invention will be explained in more detail below. The glass composition used in the present invention is composed of calcium metaphosphate (CaO・P ₂ O ₅ ), which has a chain structure both in the glass state and in the crystalline state, and has a suitable melting temperature and a suitable temperature for easy casting. The atomic ratio Ca/P of calcium and phosphorus is in the range of 0.5 to 0.7 so as to have melt viscosity, that is, CaO 28 to 36WT%, P ₂ O ₅ 72 to
A composition of 64wt% is optimal. If the Ca/P ratio exceeds 0.7, vitrification becomes difficult, which is undesirable, and if it is lower than 0.5, the phosphorus component becomes excessive and water resistance decreases, which is undesirable. Calcium phosphate glass with this composition is based on the composition of natural teeth and aggregates, that is, mainly calcium phosphate crystalline and amorphous, and the atomic ratio of calcium and phosphorus is Ca/
The composition is very similar to that of P in the range of about 1.75 to 2.0, and has good affinity with living organisms. According to the glass having such a composition, materials for artificial living bodies such as artificial dental materials and artificial aggregates can be obtained through a simple process of pouring the glass raw material powder into a glass-like molten mold and crystallizing it. be able to. In the present invention, Al ₂ O ₃ is added to the calcium phosphate crystalline glass having the above composition in order to improve the water resistance of the glass and to promote uniform crystallization in the crystallization process. The content should be 0.5 to 5 mol%. If the addition ratio of Al ₂ O ₃ exceeds 5 mol %, it will be difficult to melt and vitrify the calcium phosphate crystalline glass, which is undesirable, and if it is lower than 0.5 mol %, the effect of improving water resistance will be lowered, which is undesirable. . Furthermore, in the present invention, Al ₂ O ₃ is added as an additive to calcium phosphate crystalline glass.
R ₂ O (R represents Na, K, Li) is added. Conventionally, addition of alkali metal oxides such as Na ₂ O and K ₂ O lowers the melting temperature of vitrification, but it also lowers strength and causes elution of the alkali metal oxides, which is unfavorable for compatibility with living organisms. It was said that
0.05mol%~ _0.5mol % with addition of _Al2O3
It has been found that by adding R ₂ O, particularly preferably Na ₂ O and Li ₂ O, the initial strength is improved and the occurrence of cracks is suppressed. The addition ratio of R ₂ O is
If it exceeds 0.5 mol%, the crystal particle size will be larger than the preferred crystal particle size of about 1 μm, for example, about 10 μm, which is undesirable because the strength of the calcium phosphate crystalline glass will decrease, and if it is lower than 0.05 mol%, the initial strength will be improved. This is not preferable because no effect can be obtained. The improvement in initial strength due to the addition of R ₂ O is due to the fact that it suppresses the occurrence of cracks that tend to occur during crystallization by suppressing the amount and physical properties of the glass phase that exists between the crystal grains that precipitate during the crystallization process. This is thought to be the reason. In producing the calcium phosphate crystalline glass of the present invention, as raw materials CaO or a calcium compound that can become CaO, a phosphoric acid compound that can become P ₂ O ₅ , and an aluminum compound that can become Al ₂ O ₃ or Al ₂ O ₃ are used as raw materials. and at least one kind of alkaline compound such as a sodium compound, a potassium compound, a lithium compound, etc., are mixed, slurried if necessary, dried, and crushed to produce calcium phosphate containing Al ₂ O ₃ and R ₂ O. Prepare a powder and melt it. When producing a biological component from this calcium phosphate crystalline glass, the melt is poured into a mold to form a predetermined shape, and then crystallized to obtain a final product. The most typical calcium compounds mentioned above are calcium carbonate and calcium oxide.
Other calcium hydroxide, calcium hydrogen carbonate,
Inorganic and organic salts of calcium such as oxalic acid and calcium acetate are produced. Further, as the phosphorus compound, phosphoric acids such as orthophosphoric acid, or ammonium salts of these phosphoric acids are used. In addition, calcium phosphates such as calcium phosphate, calcium hydrogen phosphate, calcium dihydrogen phosphate, calcium pyrophosphate, acidic calcium phosphate, calcium polyphosphate, and hydroxyabatite can also be used alone or in combination with other calcium compounds or phosphorus compounds. You can also use Further, as the aluminum compound, aluminum hydroxide, aluminum oxide, aluminum nitrate, etc. are used. In addition, examples of alkali compounds include carbonates, hydrates, nitrates, and alkali metals (L, Na, K, etc.).
Acetate, hydrogen carbonate, etc. are used. Furthermore, in addition to the Ca, P, Al, and R ₂ O mentioned above, a Ni compound or Fe compound may be added as a coloring agent alone or in a mixture of about 0.001 to 1 mol % to produce a tooth-like color. is also possible. For example, in manufacturing the above-mentioned calcium phosphate-based crystalline glass biological parts, 32 to 42 mol% of finely pulverized CaCO ₃ and 55 to 66 mol of H ₃ PO ₄ are used.
%, powdered Al(OH) ₃ 0.5-5.5 mol%,
0.03 to 0.4 mol% of Na ₂ CO ₃ is weighed and mixed, water is added to this to form a slurry, this is dried and crushed to prepare calcium phosphate powder containing an Al component and an alkaline component, This is fired at 200 to 900°C for 1 to 10 hours to prepare a glass raw material. Next, put the required amount of this glass raw material into a platinum crucible.
After heating and melting at 900 to 1500℃ for 5 minutes to 10 hours to homogeneously vitrify, the wax is incinerated in advance based on the lost wax method, for example, and the molten glass is cast into the investment material maintained at 500 to 800℃. ,
Shape. This molded body is taken out together with the investment material or from the investment material and subjected to a crystallization treatment. The means for crystallizing this glass molded body is not particularly limited, and for example, a method of holding it in an atmosphere at 500 to 900°C for 5 minutes to 100 hours is used. Through this crystallization treatment, a calcium phosphate crystallized glass having a crystallinity of 20% or more is obtained. (Example) Next, an example of the present invention will be described. Example 1 H corresponding to 49.4 mol% as P ₂ O ₅ in a _mixture of CaCO ₃ powder corresponding to 49.5 mol % as CaO and Al(OH) ₃ powder corresponding to 1.0 mol % as Al ₂ O 3 0.1 mol as phosphoric acid and Na ₂ O containing ₃ PO ₄
% of NaOH and the resulting reaction product was dried and crushed, and then the powder was heated at 400℃ for 5 minutes.
The fired product is heated to 1250℃ in a platinum crucible.
After melting under stirring for 2 hours, the mixture was poured onto a graphite plate and slowly cooled. The thus obtained calcium phosphate crystalline glass with a Ca/P ratio of 0.50 is 2 mm square and 50 mm long.
Cut it into a rod shape, crystallize it at 630℃ for 20 hours,
Table 1 shows the results of measuring the bending strength of the obtained crystallized glass. Example 2 In a mixture of _CaCO3 powder corresponding to 51.8 mol% as CaO and Al(OH) _{3 powder} corresponding to 1 mol% as _Al2O3 , H corresponding to _47.1 mol% as _P2O5 was added. As phosphoric acid _{and Na2O} containing _3PO4
The reaction product obtained by adding NaOH corresponding to 0.1 mol% was dried and crushed, and then the powder was
Calcinate at ℃ for 5 hours and place this fired product in a platinum crucible.
After melting under stirring at 1250°C for 2 hours, the mixture was poured onto a graphite plate and slowly cooled. The thus obtained calcium phosphate crystalline glass with a Ca/P ratio of 0.55 is 2 mm square with a length of 50 mm.
Cut it into a rod shape, crystallize it at 630℃ for 20 hours,
Table 1 shows the results of measuring the bending strength of the obtained crystallized glass. Example 3 H corresponding to _43.8 mol% as _P2O5 in _{a mixture of CaCO3 powder corresponding to 55.1 mol% as CaO and Al(OH)3 powder corresponding to} 1.0 mol% as Al2O3 0.1 mol as phosphoric acid and Na ₂ O containing ₃ PO ₄
% of NaOH and the resulting reaction product was dried and crushed, and then the powder was heated at 400℃ for 5 minutes.
The fired product is heated to 1250℃ in a platinum crucible.
After melting under stirring for 2 hours, the mixture was poured onto a graphite plate and slowly cooled. The thus obtained calcium phosphate crystalline glass with a Ca/P ratio of 0.63 is 2 mm square with a length of 50 mm.
Cut it into a rod shape, crystallize it at 630℃ for 20 hours,
Table 1 shows the results of measuring the bending strength of the obtained crystallized glass. Comparative Example 1 H3 corresponding to 49.5 mol% as _P2O5 in a _{mixture of CaCO3 powder corresponding to 49.5 mol% as CaO and Al(OH)3 powder corresponding to 1} mol% as _Al2O3. The reaction product obtained by adding phosphoric acid containing PO ₄ was dried and crushed, and then the powder was
Calcinate at ℃ for 5 hours and place this fired product in a platinum crucible.
After melting under stirring at 1250°C for 2 hours, the mixture was poured onto a graphite plate and slowly cooled. The thus obtained calcium phosphate crystalline glass with a Ca/P ratio of 0.50 is 2 mm square and 50 mm long.
Cut it into a rod shape, crystallize it at 630℃ for 20 hours,
Table 1 shows the results of measuring the bending strength of the obtained crystallized glass. Comparative Example 2 H3 corresponding to _{47.1 mol% as P2O5 in} a _{mixture of CaCO3 powder corresponding to 51.9 mol% as CaO and Al(OH)3 powder corresponding to} 1 mol% as _Al2O3. The reaction product obtained by adding phosphoric acid containing PO ₄ was dried and crushed, and then the powder was
Calcinate at ℃ for 5 hours and place this fired product in a platinum crucible.
After melting under stirring at 1250°C for 2 hours, the mixture was poured onto a graphite plate and slowly cooled. The thus obtained calcium phosphate crystalline glass with a Ca/P ratio of 0.55 is 2 mm square with a length of 50 mm.
Cut it into a rod shape, crystallize it at 630℃ for 20 hours,
Table 1 shows the results of measuring the bending strength of the obtained crystallized glass. Comparative Example 3 H corresponding to 43.8 mol% as P ₂ O ₅ in _a mixture of CaCO ₃ powder corresponding to 55.2 mol % as CaO and Al(OH) ₃ powder corresponding to 1.0 mol % as Al ₂ O 3 The reaction product obtained by adding phosphoric acid containing ₃ PO ₄ was dried and crushed, and then the powder was
Calcinate at ℃ for 5 hours and place this fired product in a platinum crucible.
After melting under stirring at 1250°C for 2 hours, the mixture was poured onto a graphite plate and slowly cooled. The thus obtained calcium phosphate crystalline glass with a Ca/P ratio of 0.63 is 2 mm square with a length of 50 mm.
Cut it into a rod shape, crystallize it at 630℃ for 20 hours,
Table 1 shows the results of measuring the bending strength of the obtained crystallized glass. Example 4 H3 corresponding to _{46.0 mol% as P2O5 in} a mixture of _CaCO3 powder corresponding to 50.7 mol% as _CaO and Al(OH) ₃ powder corresponding to ₃ mol% as _Al2O3 0.3mol as phosphoric acid and _Na2O containing _PO4
% of NaOH and the resulting reaction product was dried and crushed, and then the powder was heated at 400℃ for 5 minutes.
The fired product is heated to 1250℃ in a platinum crucible.
After melting under stirring for 2 hours, the mixture was poured onto a graphite plate and slowly cooled. The thus obtained calcium phosphate crystalline glass with a Ca/P ratio of 0.55 is 2 mm square with a length of 50 mm.
Cut it into a rod shape, crystallize it at 630℃ for 20 hours,
Table 1 shows the results of measuring the bending strength of the obtained crystallized glass.

[Table] As is clear from the above Examples, Comparative Examples, Table 1, and Figure 1, 1 to 5 mol% of Al ₂ O ₃ and 1 to 5 mol% of R ₂ O
Contains 0.05-0.5 mol%, Ca/P atomic ratio 0.5-0.7
Calcium phosphate crystallized glass obtained by crystallizing calcium phosphate crystallized glass is
Compared to calcium phosphate-based crystallized glass with a Ca/P atomic ratio of 0.5 to 0.7, which contains only 1 to 5 mol% of Al ₂ O ₃ , it has higher initial strength and strength after a water immersion test, and has excellent water resistance. ing. Moreover, the crystallized glass obtained by the present invention can be easily molded into complex shapes by casting methods such as the lost wax method. Ideal as an artificial dental material for inlays, bridges, etc. In the present invention, calcium phosphate-based crystalline glass means one that has been uncrystallized, and crystallized glass means one that has been crystallized.

[Brief explanation of drawings]

FIG. 1 is a drawing showing the relationship between the Ca/P atomic ratio and the bending strength of the calcium phosphate crystallized glasses of Examples 1 to 3 and Comparative Examples 1 to 3. Δ indicates Examples 1 to 3. 〇 indicates Comparative Example 1~
3 is shown.

Claims (1)

[Claims] 1 Calcium to phosphorus atomic ratio Ca/P is 0.5 to 0.7
For calcium phosphate crystalline glass,
A calcium phosphate-based crystalline glass for biological use, characterized by containing 0.5 to 5 mol% of Al ₂ O ₃ and 0.05 to 0.5 mol % of R ₂ O (R represents Na, K, or Li).