EP0353476A2
Expired / Lapsed
EP
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Biomedical material and method for making the same
Assignee: TDK Corp
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Filing: 1989-07-04
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Granted: —
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Expires: 2009-07-04
Abstract
Abstract A biomedical material for use as artificial bone and dental root is provided which takes the form of a sintered composite body comprising a crystalline calcium phosphate matrix and inorganic whiskers dispersed therein. The inorganic whiskers contain at least one oxide selected from the group consisting of silicon oxdie, aluminum oxide, calcium oxide and magnesium oxide. The matrix of tricalcium phosphate or apatite preferably has a grain size of 0.05 to 30 µm. The whiskers, typically anorthite and diopside whiskers occupy 0.5 to 95% by area of a cross section of the sintered body, and preferably have a length of 0.05 to 30 µm and an aspect ratio of from 1.2 to 100, with the ratio of matrix grain size to whisker length being 10/1 to 1/10. The material has physical toughness and strength and biomedical affinity. The material is prepared by mixing calcium phosphate and a whisker-forming material or whiskers and sintering the mixture at a temperature of 800 to 1600°C.
Inventors
- 👤 Tohru Nonami
- 👤 Nobuo Yasui
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 20:05
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/447; A; A61; A61C; A61C8/00; A61C8/0012; A61F; A61F2/00; A61F2/02; A61F2/28; A61L; A61L27/00; A61L27/02; A61L27/12; C04B35/16; C04B35/18; C04B35/195; C04B35/20; C04B35/22; C04B35/44; C04B35/622; C04B35/64; C04B35/645; C04B35/71; C04B35/78; C04B35/80; A61F2/30; A61F2/3094; A61F2002/30968; A61F2310/00; A61F2310/00005; A61F2310/00179; A61F2310/00293; C04B2235/00; C04B2235/02; C04B2235/30; C04B2235/32; C04B2235/3205; C04B2235/3206; C04B2235/3208; C04B2235/3212; C04B2235/3217; C04B2235/3222; C04B2235/34; C04B2235/3418; C04B2235/3427; C04B2235/3436; C04B2235/3445; C04B2235/3454; C04B2235/3463; C04B2235/3481; C04B2235/44; C04B2235/444; C04B2235/445; C04B2235/50; C04B2235/52; C04B2235/5208; C04B2235/5216; C04B2235/522; C04B2235/5224; C04B2235/5228; C04B2235/5232; C04B2235/524; C04B2235/5244; C04B2235/526; C04B2235/5268; C04B2235/5276; C04B2235/5296; C04B2235/54; C04B2235/5409; C04B2235/65; C04B2235/656; C04B2235/6565; C04B2235/70; C04B2235/74; C04B2235/77; C04B2235/78; C04B2235/785; C04B2235/786; C04B2235/80; C04B2235/85; C04B2235/96
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
59 words
A biomedical material in the form of a sintered composite body comprising a crystalline calcium phosphate matrix and inorganic whiskers dispersed therein, the whiskers occupying 0.5 to 95% by area of a cross section of the sintered body, and containing at least one oxide selected from the group consisting of silicon oxide, aluminum oxide, calcium oxide and magnesium oxide.
Claim 2
Dependent Claim
59 words
A biomedical material in the form of a sintered composite body comprising a crystalline calcium phosphate matrix and inorganic whiskers dispersed therein, the whiskers occupying 0.5 to 95% by area of a cross section of the sintered body, and containing at least one oxide selected from the group consisting of silicon oxide, aluminum oxide, calcium oxide and magnesium oxide.
Claim 3
Dependent Claim
56 words
The biomedical material of claim 1 wherein the matrix has a grain size of 0.05 to 30 µm, and the whiskers have a length of 0.05 to 30 µm and an aspect ratio as defined by length/diameter of from 1.2/1 to 100/1, the ratio of matrix grain size to whisker length ranging from 10/1 to 1/10.
Claim 4
Dependent Claim
14 words
The biomedical material of claim 1 wherein the crystalline calcium phosphate is tricalcium phosphate.
Claim 5
Dependent Claim
15 words
The biomedical material of claim 1 wherein the crystalline calcium phosphate is of apatite series.
Claim 6
Dependent Claim
26 words
The biomedical material of claim 4 wherein the crystalline calcium phosphate is hydroxyapatite or fluoroapatite having an atomic calcium-to-phosphorus (Ca/P) ratio of from 165/100 to 175/100.
Claim 7
Dependent Claim
34 words
The biomedical material of claim 1 wherein the inorganic whiskers are selected from the group consisting of alumina, calcium silicate, aluminum silicate, aluminum silicate calcium, calcium silicate magnesium, calcium aluminate, and magnesium silicate whiskers.
Claim 8
Dependent Claim
32 words
The biomedical material of claim 1 wherein the whiskers contain at least two oxides selected from the group consisting of silicon oxide, aluminum oxide and calcium oxide, and optionally contain magnesium oxide.
Claim 9
Dependent Claim
25 words
The biomedical material of claim 7 wherein the inorganic whiskers are selected from the group consisting of aluminum silicate calcium, and calcium silicate magnesium whiskers.
Claim 10
Dependent Claim
15 words
The biomedical material of claim 8 wherein the inorganic whiskers are anorthite or diopside whiskers.
Claim 11
Dependent Claim
35 words
The biomedical material of claim 1 wherein an intermediate layer is present between the whiskers and the matrix grains, the intermediate layer containing elements in either one or both of the whiskers and the matrix.
Claim 12
Dependent Claim
26 words
The biomedical material of claim 10 wherein the intermediate layer has a continuous or stepwise gradient of concentration and a thickness of up to 3 µm.
Claim 13
Dependent Claim
18 words
The biomedical material of claim 1 wherein the whiskers have a degree of orientation of at least 60%.
Claim 14
Dependent Claim
43 words
A method for preparing a biomedical material as defined in claim 1, comprising mixing a calcium phosphate material and a whisker-forming material, and sintering the mixture at a sufficient temperature of 800 to 1600°C for a sufficient time to allow whiskers to grow.
Claim 15
Dependent Claim
32 words
The method of claim 13 wherein the temperature at which the whisker-forming material forms whiskers is higher by 50 to 400°C than the temperature normally required for sintering the calcium phosphate material.
Claim 16
Dependent Claim
39 words
The method of claim 13 wherein the whisker-forming material is a mixture or compound consisting essentially of (i) at least one member of an alumina source and magnesia source, (ii) a silica source, and (iii) a calcium oxide source.
Claim 17
Dependent Claim
35 words
The method of claim 13 which further comprises cooling the sintered material at a sufficiently slow rate of up to 30°C/min. to allow an intermediate layer to form between the matrix grains and the whiskers.
Claim 18
Dependent Claim
52 words
A method for preparing a biomedical material as defined in claim 1, comprising mixing a calcium phosphate material and inorganic whiskers having a length of 0.05 to 30 µm and an aspect ratio as defined by length/diameter of 1.2/1 to 100/1, and sintering the mixture at a temperature of 800 to 1600°C.
Claim 19
Dependent Claim
25 words
The method of claim 17 which further comprises rolling the mixture of calcium phosphate and inorganic whiskers for whisker orientation before the mixture is sintered.
References Cited (Backward Citations)
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