JP3005025B2 - Calcium phosphate crystallized glass - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a calcium phosphate crystallized glass, particularly to a calcium phosphate crystallized glass that can be suitably used as a dental material.

[Prior art] Conventionally, calcium phosphate crystallized glass has excellent moldability, and has high mechanical strength and can give an appearance similar to natural teeth. ing. As calcium phosphate crystallized glass for dental materials, JP-A-63-260839, JP-A-60-
As disclosed in Japanese Patent Publication No. 210546, a material containing a strontium oxide has also been proposed.

[Problem to be Solved by the Invention] However, a material having sufficient mechanical strength and chemical durability enough to withstand long-term use in the mouth, and having high transparency that looks very similar to natural teeth in appearance is required. Not obtained.

In a calcium phosphate-based composition, the chemical durability tends to be low in a composition that gives a crystallized glass having high transparency and high mechanical strength in appearance. Conversely, a composition that provides a crystallized glass having high chemical durability tends to have low transparency and low strength. Therefore, when a particularly high aesthetic clarity is required, the chemical durability cannot be sufficiently satisfied.

[Means for Solving the Problems] The present inventor has developed a crystallized glass having a high transparency that gives sufficient aesthetics when applied to a dental material, and also having excellent mechanical strength and chemical durability. As a result of various studies and studies for the purpose of obtaining, it has been found that the above-mentioned object can be achieved by crystallizing a glass having a composition in which the calcium component of the calcium phosphate glass is replaced with a specific amount of strontium.

Thus, the present invention is 13 to 20 wt% of an oxide of phosphorus 64-72 wt% in terms _of P ₂ O _5, an oxide of calcium in terms of CaO,
6-13% by weight of strontium oxide as SrO, A
l, Ce, and at least one oxide selected from La oxides, each containing a total of ₃ to 15% by weight in terms of Al ₂ O ₃ , Ce ₂ O ₃ , and La ₂ O ₃ , and (CaO + SrO) / P ₂ O _The present invention provides a calcium phosphate crystallized glass having a molar ratio of 0.78 to 0.86.

Oxides of phosphorus in the present invention in terms of P ₂ O ₅ 64 to 72
Weight percent. P ₂ If O ₅ is less than 64 wt%, during crystallization, mechanical strength minute cracks are generated between the crystal grains becomes lower Moreover less transparent crystallized glass, P ₂ O ₅ in the opposite If the content exceeds 72% by weight, crystallized glass having low chemical durability will be obtained, and all are unsuitable.

The calcium oxide needs to be 13 to 20% by weight in terms of CaO. If CaO is less than 13% by weight, the glass becomes a crystallized glass with low chemical durability. Conversely, if CaO exceeds 20% by weight, micro-cracks are generated between the crystal grains during crystallization, and the mechanical strength is reduced. Any of these is unsuitable because it results in crystallized glass that is low and has low transparency.

The strontium oxide needs to be 6 to 13% by weight in terms of SrO. If the content of SrO is less than 6% by weight, the mechanical strength is insufficient, so that it is inappropriate. SrO is 1
If it exceeds 3% by weight, the chemical durability becomes insufficient, and all are unsuitable.

Aluminum, cerium, and lanthanum oxides are converted to Al ₂ O ₃ , Ce ₂ O ₃ , and La ₂ O ₃ , respectively, for a total of ₃ to 15% by weight.
Need to be If the total content of Al ₂ O ₃ , Ce ₂ O ₃ , and La ₂ O ₃ is less than 3% by weight, the chemical durability is insufficient, which is inappropriate. If the total amount of Al ₂ O ₃ , Ce ₂ O ₃ , and La ₂ O ₃ exceeds 15% by weight, crystallized glass with low transparency is obtained, and any of them is inappropriate. Also, it is preferable that Al ₂ O ₃ , Ce ₂ O ₃ and La ₂ O ₃ alone do not exceed 5% by weight. Al ₂ O ₃ , Ce ₂ O ₃ ,
When the content of La ₂ O ₃ alone exceeds 5% by weight, it is not preferable because crystallized glass having low transparency may be obtained.

The molar ratio of _{(CaO + SrO) / P 2} O 5 , it is necessary to 0.78 to 0.86. If the molar ratio of (CaO + SrO) / P ₂ O ₅ is less than 0.78, the chemical durability becomes insufficient, which is inappropriate.
When the molar ratio of (CaO + SrO) / P ₂ O ₅ is larger than 0.86, the mechanical strength is insufficient and the crystallized glass has low transparency.

And in these ranges, P ₂ O ₅ is 65-69% by weight, Ca
O is 15 to 20 wt%, SrO 7 to 11 _{wt%, Al 2 O 3, Ce} 2 O 3,
When the total amount of La ₂ O ₃ is 5 to 10% by weight and the molar ratio of (CaO + SrO) / P ₂ O ₅ is 0.80 to 0.84, the transparency, mechanical strength, and chemical durability are all the same. It is particularly preferred because it can be most effectively improved.

In the production of the crystallized glass of the present invention, the following materials can be used as raw materials.

Phosphorus materials include, for example, phosphoric acids such as orthophosphoric acid, and ammonium salts of these phosphoric acids. In addition, calcium salts of phosphoric acids such as calcium phosphate and calcium hydrogen phosphate can be used in combination with other calcium compounds and phosphorus compounds. Further, ammonium salts of phosphoric acids such as aluminum phosphate can also be used as a mixture with other aluminum compounds and phosphorus compounds.

As the calcium and strontium raw materials, for example, oxides and carbonates are typical, but other hydroxides,
Inorganic salts and organic salts such as oxalates and acetates can be used as appropriate.

As an aluminum, cerium, or lanthanum raw material, it is preferable to use an oxide. In addition, a compound which can be converted to an oxide by heating and firing such as a hydroxide or a sulfate can be used.

In producing the crystallized glass of the present invention, first, a homogeneous glass is produced from the above-mentioned raw materials.
Such a glass, for example, after weighing and mixing a predetermined amount of various raw materials, and firing this at 200 to 900 ° C. for about 1 to 10 hours,
It can be preferably manufactured by heating and melting in a platinum crucible at 900 to 1500 ° C. for 5 minutes to 10 hours.

The glass thus obtained is appropriately shaped after cooling or solidifying, and then heat-treated to be crystallized to obtain crystallized glass. In the crystallization treatment, the glass once cooled to around room temperature may be heated again to the crystallization temperature, or the glass melt may be cooled to the crystallization temperature below the glass softening point and crystallized as it is.

The crystallized glass of the present invention can be particularly preferably used for dental materials such as crown restoration materials. The melt having the composition of the crystallized glass of the present invention can be cast and formed precisely as in the case of ordinary metal for crown materials.

The crystallized glass crown can be preferably manufactured by the following method. The melt having the above-mentioned crystallized glass composition (the glass once solidified may be re-melted) is cast and molded in a mold manufactured by a lost wax method similar to a usual dental metal material. As the casting apparatus, a centrifugal casting machine, a vacuum pressure casting machine, and a pressure casting machine can be suitably used.

Next, the molded body is taken out of the investment material or taken out of the investment material, and kept at a temperature of 500 to 900 ° C. for 5 minutes to 100 hours for crystallization. At this time, crystallization in the investment material is preferable because dimensional change and deformation are reduced. In the case of crystallizing by taking out from the investment material, there is an advantage that it can be crystallized after confirming the presence or absence of a casting defect and correcting the shape in a transparent glass state. In this case, the deformation can be suppressed by re-embedding in a material that does not react with the glass at the crystallization temperature such as the alumina powder or the investment material during crystallization.

After crystallization, if crystallized in the investment material, the crystallized glass is taken out of the investment material, and the sprue portion (runner) is cut and the surface is polished to obtain a crystallized glass crown.

Further, in the present invention, Ni, Fe, Co, Rh, Ru, Pd
By containing a total of 0.001 to 3.0% by weight of a metal element or one or more selected from compounds as a metal element, the crystallized glass can have a color tone much more similar to natural teeth. As these raw materials, besides simple metals, oxides and compounds that can become oxides when the glass is melted, for example, hydroxides, sulfides, halides, carbonates, and organic acid salts can be used.

Further, in the present invention, at least one of the oxides of Li, Na and K can be added in an amount of 0.01 to 15% by weight in terms of Li ₂ O, Na ₂ O and K ₂ O. Thereby, the mechanical strength of the crystallized glass is improved. 0.01% by weight of this oxide
If less than the above, the effect of the additive is not sufficiently exhibited.
Conversely, if the content exceeds 15% by weight, the chemical durability of the crystallized glass may decrease, which is not preferable. Li, Na,
As a raw material of K, for example, a simple substance, a hydroxide, a carbonate, a nitrate, a sulfate, a halide, an organic acid salt, or the like can be appropriately used in addition to the oxide.

[Examples] Examples 1 to 7 A total of 400 g of raw materials were obtained so that the composition shown in Table 1 was obtained when glass was produced.
Weighed and mixed well. This was baked at 400 ° C. for 5 hours and dried, then put into a platinum crucible and melted at 1300 ° C. for 2 hours. Thereafter, the mixture was poured on a stainless steel plate and quenched to obtain glass.

This glass was re-melted and formed into a 2 mmφ × 25 mm cylindrical shape in the same manner as in a normal dental metal casting method. Thereafter, heat treatment was performed in a mold at 700 ° C. for 16 hours to crystallize. The bending strength was measured using five pieces of this crystallized glass. The crystallized glass was immersed in ion-exchanged water at 80 ° C. for 72 hours, and the weight loss was measured. The results are shown in Table 2 together with the appearance.

[Effect of the Invention] The crystallized glass of the present invention has high mechanical strength, high chemical durability, and has an appropriate translucency.
The crystallized glass of the present invention can be suitably used for a dental material, particularly a crown restoration material.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C03C 10/00-10/16 A61K 6/033 A61C 13/083

Claims (3)

(57) [Claims] (1) an oxide of phosphorus is 64 to 72% by weight in terms of P ₂ O ₅ ;
13 to 20% by weight of calcium oxide in terms of CaO, 6 to 13% by weight of strontium oxide in terms of SrO, and at least one selected from oxides of aluminum, cerium, and lanthanum, respectively, Al ₂ O ₃ , Ce _A calcium phosphate crystallized glass containing a total of ₃ to 15% by weight in terms of ₂ O ₃ and La ₂ O ₃ and a molar ratio of (CaO + SrO) / P ₂ O ₅ of 0.78 to 0.86. 2. The method according to claim 1, wherein at least one selected from a single metal or a compound of Ni, Fe, Co, Rh, Ru, and Pd is used as a metal element.
2. The calcium phosphate crystallized glass according to claim 1, which contains 001 to 3.0% by weight. 3. A dental material comprising the calcium phosphate crystallized glass according to claim 1.