JP4646353B2 - Composite biomaterial - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a composite biomaterial having a hydration curable apatite and suitable for artificial bones and bone cements, or artificial tooth roots, dental implants and dental cements, and a method for producing the same.
[0002]
[Prior art]
Conventionally, ceramic materials such as alumina ceramics and apatite ceramics have been put to practical use as composite biomaterials such as artificial bones and artificial tooth roots because of high strength and excellent biocompatibility.
[0003]
Above all, alumina ceramics need to be screwed to the living bone to fix it in the living body without adhering to the bone. Apatite ceramics such as hydroxyapatite that can be eaten and have bone tissue adhesively bonded to these materials are suitably used as composite biomaterials.
[0004]
The apatite ceramic is produced by adding a predetermined organic binder and a solvent to calcium phosphate powder and forming the powder into a predetermined shape, followed by firing at about 1100 to 1300 ° C.
[0005]
On the other hand, a cement mainly composed of calcium phosphate is used as a filler for a bone defect part, a joint between a living bone and an artificial bone, or a tooth root canal part. For example, in Japanese Patent No. 2638619, a calcium phosphate cement contains Biomaterials in which fibers are dispersed are disclosed and described as being capable of increasing strength.
[0006]
[Problems to be solved by the invention]
However, conventional calcium phosphate ceramics need to be fired, and the dimensional accuracy of the ceramics cannot be increased due to shrinkage due to sintering, and precision processing must be performed separately after firing. There was a problem that it took time and effort to process.
[0007]
In addition, in the structure in which the fiber is added to and mixed with the calcium phosphate powder described in Japanese Patent No. 2638619, and water is added to the resulting powder to harden the cement, the amount of added fiber is increased. Although the strength of the structure is improved, there is a limit to the amount of fibers that can be added to the biomaterial because the fibers are entangled and aggregated or voids are generated as the amount of added fibers increases. Further improvement in strength and toughness has been demanded.
[0008]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a composite biomaterial mainly composed of apatite that can be easily manufactured with high dimensional accuracy and has improved strength and toughness. is there.
[0009]
[Means for Solving the Problems]
As a result of examining the above-mentioned problems, the present inventor has excellent biocompatibility by including an inorganic filler composed of a specific component and an inorganic fiber in a hydrated curable matrix mainly composed of calcium phosphate. It has been found that a high-strength, high-toughness biomaterial can be produced with high dimensional accuracy.
[0010]
That is, the composite biomaterial of the present invention includes an inorganic filler containing at least one selected from the group consisting of alumina, mullite, silicon nitride, zirconia and silicon carbide in a hydration curable matrix mainly composed of apatite, and a fiber bundle. Inorganic fibers composed of one of wool-like fibers, non-woven fabrics, and woven fabrics .
[0011]
Here, before Symbol inorganic fibers, carbon, silicon carbide, silicon nitride, be at least one selected from alumina and mullite, as the inorganic filler, it is desirable to further contain apatite sintered particles.
[0012]
The composite biomaterial preferably has an average pore diameter of 50 μm or less by mercury porosimetry.
[0013]
The method for producing a composite biomaterial according to the present invention includes a calcium phosphate raw material containing at least one selected from the group consisting of alumina, mullite, silicon nitride, zirconia and silicon carbide, a fiber bundle, a wool fiber, and a nonwoven fabric. A slurry is prepared by adding inorganic fibers made of one of woven fabric and water or pseudo body fluid, and the slurry is poured into a mold and cured, and then the mold is released. And
[0014]
Furthermore, in another method for producing the composite biomaterial of the present invention, an inorganic filler containing at least one selected from the group consisting of alumina, mullite, silicon nitride, zirconia and silicon carbide, and water or simulated body fluid is added to the calcium phosphate raw material. Then, a slurry is prepared, and after filling the slurry into a skeleton containing inorganic fibers made of one of fiber bundles, wool fibers, nonwoven fabrics and woven fabrics formed in a mold, the slurry is cured. The mold is released from the mold.
[0015]
Furthermore, still another method for producing the composite biomaterial of the present invention is to prepare a slurry by adding water or a simulated body fluid to a calcium phosphate raw material, and the slurry is formed into alumina, mullite, silicon nitride formed in a mold. A skeleton containing inorganic fibers made of one of a fiber bundle, a wool-like fiber, a nonwoven fabric and a woven fabric in which an inorganic filler containing at least one selected from the group of zirconia and silicon carbide is dispersed; After curing, the mold is released.
[0016]
The composite biomaterial can be suitably used as an artificial bone or an artificial tooth root.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
A schematic diagram of one embodiment of the composite biomaterial of the present invention is shown in FIG.
According to FIG. 1, the composite biomaterial 1 includes an inorganic filler 3 containing at least one selected from the group consisting of alumina, mullite, silicon nitride, zirconia, and silicon carbide in a hydration curable matrix 2 mainly composed of calcium phosphate. And the inorganic fiber 4 is contained and dispersed.
[0018]
The hydration curable matrix 2 mainly composed of calcium phosphate is composed of aggregates of hydroxyapatite (Ca ₁₀ (PO ₄ ) ₆ (OH) ₂ ) plate-like fine particles having an average major axis of 3 μm or less, particularly 0.2 to 2 μm, As for the composition of hydroxyapatite, it is desirable that the Ca / P molar ratio is smaller than 1.67, as in the case of living bones, in terms of adhesion characteristics with living bones. It should be noted that the content ratio of the hydration curable matrix 2 is 10 to 50% by volume, particularly 15 to 40% by volume in terms of adhesion characteristics with living bones and the strength and toughness of the composite biomaterial 1. desirable.
[0019]
Further, the inorganic fiber 4 has an average length of at least one selected from carbon, silicon carbide, silicon nitride, alumina, mullite, zirconia, for example, 30 μm or more, particularly 50 μm or more, further 0.1 mm or more, more preferably 1 mm or more. Thus, those having an average diameter of 1 to 30 μm, particularly 5 to 20 μm, and an aspect ratio of 3 or more, particularly 10 or more can be suitably used.
[0020]
Also, inorganic fibers 4 are in hydrated curable matrix 2 may be randomly distributed, but is made of a fiber維束, one of wool-like fibers, nonwovens and woven fabrics. In this case, by setting the average diameter of the inorganic fibers 4 to 30 μm or less, particularly 20 μm or less, and further 10 μm or less, the inorganic fibers 4 can be processed into a desired shape, and a fiber structure having a complicated shape can be produced. Moreover, the filling property of the hydration curable matrix 2 and the inorganic filler 3 into the inorganic fiber 4 can be enhanced.
[0021]
In addition, the content ratio in the composite biomaterial 1 of the inorganic fiber 4 and the inorganic filler 3 is 50 to 90 volume% in total in terms of improving the strength and toughness of the material and reducing the porosity inside the material, and particularly 60 to The content of the inorganic fiber 4 is preferably 20% by volume or more, particularly 30% by volume or more, more preferably 50 to 70% by volume, based on the total amount of the inorganic fiber 4 and the inorganic filler 3. It is desirable that the content is 10 to 65% by volume, particularly 20 to 50% by volume, based on the entire composite biomaterial 1.
[0022]
Furthermore, the inorganic filler 3 is, for example, at least one selected from the group consisting of alumina, mullite, silicon nitride, zirconia, and silicon carbide having an average particle size of 0.1 to 30 μm, particularly 0.5 to 10 μm, and further 1 to 5 μm. It is made of ceramic particles that contain, thereby reducing the ratio of the hydration curable matrix 2 in the composite biomaterial 1 and also inhibiting the progress of cracks even if minute cracks occur in the material 1, thereby hydrating and hardening. The strength of the composite matrix 2 part can be remarkably increased, and the strength of the composite biomaterial 1 can be remarkably increased.
[0023]
The inorganic filler 3 exists in a spherical shape, an indeterminate shape, or a hollow shape, and is preferably indefinite shape, particularly in order to reinforce the bonding force between them, and further, the hydration curable matrix 2 and the inorganic filler. In addition to the inorganic filler 3, it is desirable to further contain apatite sintered particles having an average particle diameter of 3 to 200 μm, particularly 20 to 80 μm.
[0024]
In addition to the apatite sintered particles, biocompatibility such as crystallized glass in which apatite and wollastonite microcrystals are precipitated, Na ₂ O—CaO—SiO ₂ —P ₂ O ₅ bioactive glass, etc. It is also possible to add other particles that are rich in and capable of producing dense particles.
[0025]
Furthermore, the composite biomaterial 1 preferably has a high specific surface area and porosity of the hydration-curable matrix 2 present on the surface and a small pore diameter in order to enhance adhesion to living bones and the like, Considering the shape-retaining property as a structure, it is desirable that the average pore diameter by mercury porosimetry is 50 μm or less, particularly 30 μm or less, and further 20 μm or less. It should be noted that the strength and toughness of the composite biomaterial 1 are increased when the ratio of the hydration-curable matrix 2 occupying the surface of the composite biomaterial 1 is larger than the ratio of the hydration-curable matrix 2 occupying the interior of the composite biomaterial 1. It is desirable for enhancing the adhesion bonding with living bones.
[0026]
Note that the content ratio of the inorganic filler 3 is 10 to 80 with respect to the entire composite biomaterial 1 in order to increase the strength of the hydration curable matrix 2 and prevent the development of microcracks generated in the composite biomaterial 1. It is desirable that the content is not less than volume%, particularly 20 to 50 volume%, more preferably 30 to 45 volume%, and the content ratio of the inorganic filler 3 to the content ratio of the hydrated curable matrix 2 is 10 volumes with respect to the total amount. % Or more, particularly 30 to 50% by volume.
[0027]
Next, an example of a method for producing the composite biomaterial will be described.
First, the above-described hydroxyapatite (Ca ₁₀ (PO ₄ ) ₆ (OH) ₂ ) is preferably produced and cured in the presence of water or pseudo body fluid with an average particle size of 30 μm or less, particularly 15 μm or less, and even 5 μm or less. Prepare calcium phosphate raw material.
[0028]
Specifically, as a calcium phosphate raw material, α-Ca ₃ (PO ₄ ) ₂ , β-Ca ₃ (PO ₄ ) ₂ , α-Ca ₃ (PO ₄ ) ₂ -Ca ₄ O (PO ₄ ) ₂ , α-Ca ₃ (PO ₄ ) ₂ —CaHPO ₄ .2H ₂ O, 2-Ca ₄ O (PO ₄ ) ₂ —CaHPO ₄ .2H ₂ O, and the like. Among them, the above-described formation and precipitation reaction of hydroxyapatite near room temperature. Α-Ca ₃ (PO ₄ ) ₂ —CaHPO ₄ .2H ₂ O, which tends to occur quickly, can be preferably used. The Ca / P molar ratio of the calcium phosphate raw material is desirably 1.4 to 1.498 in order to increase the amount of hydroxyapatite produced and cure in a short time.
[0029]
After mixing the inorganic fiber and the inorganic filler with the calcium phosphate raw material, water or a pseudo body fluid is added, and the mixture is kneaded at room temperature or optionally heated to 40 to 80 ° C. As the simulated body fluid, specifically, an aqueous solution of 1% sodium phosphate, sodium citrate, or the like, or a mixed solution thereof can be used. In addition, it is desirable that PH of the slurry at the time of the kneading is 5 to 7.
[0030]
Then, the mixture is poured into a mold having a predetermined shape, dried and allowed to stand for a predetermined time or longer, and the mixture is cured to produce the composite biomaterial of the present invention.
[0031]
Further, in the present invention, besides the above method, a porous skeleton body made of inorganic fibers is formed in a mold, and a cement slurry containing the above-mentioned calcium phosphate and inorganic filler is poured into the porous skeleton body. After filling, the slurry can be hardened. According to this, the content ratio of the inorganic fiber and the inorganic filler is increased without generating voids in the composite biomaterial, thereby increasing the strength and toughness of the composite biomaterial. Can do.
[0032]
In order to produce the porous skeleton, a slurry containing a sol or inorganic ceramic powder for forming inorganic fibers is impregnated or mixed with a material that disappears by firing such as urethane foam or organic balls. For example, it is made by spinning an organosilicon polymer such as polycarbosilane, making it infusible in an inert atmosphere, and firing it. A fiber bundle, wool-like fiber, non-woven fabric and woven fabric-like inorganic fiber can be produced and used to produce an inorganic fiber skeleton using alumina fiber and mullite fiber spun from a precursor. The toughness of the biomaterial can be dramatically increased.
[0033]
Furthermore, an inorganic filler can be added and dispersed in the porous skeleton made of the inorganic fiber, and the slurry containing calcium phosphate is poured into the porous skeleton made of a mixture of the inorganic fiber and the inorganic filler. You can also
[0034]
【Example】
Example 1
With respect to 100 parts by weight of α- (Ca ₃ (PO ₄ ) ₂ ) raw material particles having an average particle diameter of 4.5 μm, 180 parts by weight of alumina raw material powder having an average particle diameter of 1.2 μm as an inorganic filler and poly as inorganic fibers 150 parts by weight of an amorphous SiC fiber having an average diameter of 10 μm (Tyranno fiber, manufactured by Ube Industries) cut to 5 μm in length is spun from carboxysilane and fired in an inert atmosphere. After adding a weight part and kneading at 20 ° C. to prepare a cement slurry, it is poured into a 40 mm × 40 mm × 5 mm deep cylindrical Teflon mold, left at 37 ° C. for 5 days, and dried. After curing, the mold was released to produce a composite biomaterial.
[0035]
The obtained composite biomaterial was cut out and the 4-point bending strength was measured according to JIS R1601. Moreover, it was 180 MPa when the compressive strength was measured according to JIS-R1608. Furthermore, when the average pore diameter of the composite biomaterial was measured by the mercury intrusion method, it was 27 μm, and the content ratios of the matrix, fiber, and filler were determined by the Luzex method using an SEM photograph of the polished surface of the composite biomaterial. As a result of the measurement, the matrix was 25% by volume, the fiber was 38% by volume, and the filler was 37% by volume.
[0036]
(Example 2)
To the α- (Ca ₃ (PO ₄ ) ₂ ) raw material particles of Example 1, 180 parts by weight of alumina raw material particles having an average particle diameter of 1.2 μm as an inorganic filler and 170 parts by weight of water were added and kneaded. A cement slurry was prepared.
[0037]
On the other hand, a woven fabric of polycarboxysilane of Example 1 was prepared as an inorganic fiber, and an inorganic fiber woven fabric made of amorphous SiC fibers having an average diameter of 10 μm that was fired in an inert atmosphere was prepared and cut out. An inorganic fiber skeleton was prepared by laminating in the mold of Example 1.
[0038]
And, as a result of producing and evaluating a composite biomaterial in the same manner as in Example 1 except that the cement slurry was poured into the inorganic fiber skeleton formed in the mold and filled, the 4-point bending strength was 190 MPa, The compressive strength is 300 MPa, the average pore diameter of the composite biomaterial is 25 μm, and the content ratio of each of the hydration curable matrix, fiber, and filler in the composite biomaterial is 20 vol%, 50 vol%, and 30 vol%, respectively. there were. Furthermore, as a result of SEM observation on the surface of the composite biomaterial, it was found that the content ratio of the hydration curable matrix was 40% by volume, which was larger than the inside.
[0039]
(Comparative example)
The composite biomaterial of Example 1 was prepared and evaluated in the same manner as in Example 1 except that the cement slurry was prepared without adding the inorganic filler, and the four-point bending strength was 42 MPa. The compressive strength was 85 MPa, the average pore diameter of the composite biomaterial was 29 μm, and the hydration-curable matrix and fiber content ratios in the composite biomaterial were 38% by volume and 62% by volume, respectively.
[0040]
【The invention's effect】
As described in detail above, the composite biomaterial of the present invention is a hydrated curable matrix composite biomaterial mainly composed of apatite with high dimensional accuracy and high strength and toughness.
[Brief description of the drawings]
FIG. 1 is a schematic diagram for explaining a tissue of a composite biomaterial of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Composite biomaterial 2 Hydration curable matrix 3 Inorganic filler 4 Inorganic fiber

Claims (8)

An inorganic filler containing at least one selected from the group consisting of alumina, mullite, silicon nitride, zirconia and silicon carbide in a hydration curable matrix mainly composed of apatite, and a fiber bundle, wool fiber, nonwoven fabric and woven fabric A composite biomaterial comprising an inorganic fiber composed of one of them . Said inorganic fibers are carbon, silicon carbide, a composite biomaterial according to claim 1, characterized in that it consists of at least one selected from silicon nitride, alumina and mullite. The composite biomaterial according to claim 1 or 2 , further comprising apatite sintered particles as the inorganic filler. The composite biomaterial according to any one of claims 1 to 3 , wherein an average pore diameter by a mercury intrusion method is 50 µm or less. An inorganic filler containing at least one selected from the group consisting of alumina, mullite, silicon nitride, zirconia and silicon carbide in the calcium phosphate raw material, and an inorganic fiber made of one of a fiber bundle, a wool-like fiber, a nonwoven fabric and a woven fabric ; A method for producing a composite biomaterial comprising adding water or pseudo body fluid to prepare a slurry, pouring the slurry into a mold and curing the mold, and then releasing the mold. A slurry is prepared by adding an inorganic filler containing at least one selected from the group consisting of alumina, mullite, silicon nitride, zirconia and silicon carbide to calcium phosphate raw material and water or pseudo body fluid, and forming the slurry in a mold A composite biomaterial characterized in that the mold is released after filling into a skeleton containing inorganic fibers made of one of a bundle of fibers, wool fibers, nonwoven fabrics and woven fabrics, and curing Manufacturing method. An inorganic filler containing at least one selected from the group consisting of alumina, mullite, silicon nitride, zirconia, and silicon carbide formed in a mold by adding water or pseudo body fluid to a calcium phosphate raw material to produce a slurry. The composite is characterized in that the mold is released after filling into a skeleton containing inorganic fibers made of one of fiber bundles, wool fibers, nonwoven fabrics and woven fabrics, in which the mold is dispersed. Biomaterial manufacturing method. Artificial bones or artificial tooth root made of a composite biomaterial according to any one of claims 1 to 4.

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