Patent US4846838A successfully refreshed from Google Patents.
US4846838A
Expired / Lapsed
US
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Prosthetic body for bone substitute and a method for the preparation thereof
Assignee: TDK Corp
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Filing: 1987-06-18
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Granted: 1989-07-11
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Expires: 2007-06-18
Abstract
Abstract The inventive prosthetic body for bone substitute is a sintered body of hydroxyapatite and characterized by the open pore structure with a pore diameter in a specified range forming a porosity of 20 to 40% and a bending strength of at least 100 kg/cm 2 . The sintered body can be prepared by blending powders of hydroxyapatite and a thermally decomposable substance, e.g. crystalline cellulose, each having a specified particle size distribution, in a specified proportion and shaping and sintering the powder blend.
Inventors
- 👤 Nobuharu Takai
- 👤 Hiroyasu Noma
- 👤 Shoichi Wakabayashi
- 👤 Susumu Takata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:47
CPC Classifications
A; A61; A61F; A61F2/00; A61F2/02; A61F2/28; A61L; A61L27/00; A61L27/02; A61L27/12; A61L27/50; A61L27/56; A61F2310/00; A61F2310/00005; A61F2310/00179; A61F2310/00293; A61L2430/00; A61L2430/02
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
152 words
A method for the preparation of a prosthetic body for bone substitute, which consists essentially of a sintered body of hydroxyapatite having a porosity in the range from 20 to 40% formed of open pores with a pore diameter in the range from 10 to 100 μm and having a bending strength of at least 100 Kg/cm 2 which consists essentially of: 1: blending with or without a binder 100 parts by weight of a powder of hydroxyapatite having an average particle diameter in the range from 0.1 to 10 μm with from 10 to 40 parts by weight of a thermally decomposable substance having an average particle diameter in the range of from 10 to 100 μm to give a powder blend; 2: shaping the powder blend into a selected form; and 3: sintering the shaped form of powder blend at a temperature in the range from 900° to 1400° C.
Claim 2
Independent Claim
152 words
A method for the preparation of a prosthetic body for bone substitute, which consists essentially of a sintered body of hydroxyapatite having a porosity in the range from 20 to 40% formed of open pores with a pore diameter in the range from 10 to 100 μm and having a bending strength of at least 100 Kg/cm 2 which consists essentially of: 1: blending with or without a binder 100 parts by weight of a powder of hydroxyapatite having an average particle diameter in the range from 0.1 to 10 μm with from 10 to 40 parts by weight of a thermally decomposable substance having an average particle diameter in the range of from 10 to 100 μm to give a powder blend; 2: shaping the powder blend into a selected form; and 3: sintering the shaped form of powder blend at a temperature in the range from 900° to 1400° C.
Claim 3
Dependent Claim
18 words
A method as in claim 1 wherein the thermally decomposable substance is crystalline cellulose powder or fibrous cellulose.
Claim 4
Dependent Claim
15 words
A method as in claim 1 employing a binder which is a water soluble polymer.
Claim 5
Dependent Claim
12 words
A method as in claim 3 wherein the binder is polyvinyl alcohol.
Claim 6
Dependent Claim
15 words
A method as in claim 2 employing a binder which is a water soluble polymer.
Claim 7
Dependent Claim
12 words
A method as in claim 5 wherein the binder is polyvinyl alcohol.
Claim 8
Dependent Claim
19 words
A method as in claim 1 wherein the thermally decomposable substance is polyurethane, polyethylene, nylon resin or acrylic resin.
Claim 9
Dependent Claim
28 words
A method as in claim 7 including the additional step of mixing the powder blend with an aqueous solution containing a binder which is a water soluble polymer.
Claim 10
Dependent Claim
12 words
A method as in claim 8 wherein the binder is polyvinyl alcohol.
References Cited (Backward Citations)
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Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-07-10 | 1993-01-09 | 1993-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-10 | 1997-01-09 | 1997-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-10 | 2001-01-09 | 2001-07-11 | $7700.00 | Window Closed / Lapsed |