US5639402A
Expired / Lapsed
US
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Method for fabricating artificial bone implant green parts
Assignee: The University of Texas System
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Filing: 1994-08-08
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Granted: 1997-06-17
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Expires: 2014-08-08
Abstract
Abstract Bone implants are made from calcium phosphate powders by selectively fusing layers of calcium powders that have been coated or mixed with polymer binders. The calcium powder mixture may be formed into layers and the polymer fused with a laser. Complex three-dimensional geometrical shapes can be automatically replicated or modified using this approach.
Inventors
- 👤 Joel W. Barlow
- 👤 Goonhee Lee
- 👤 Richard H. Crawford
- 👤 Joseph J. Beaman
- 👤 Harris L. Marcus
- 👤 Richard J. Lagow
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 06:23
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/622; C04B35/626; C04B35/628; A; A61; A61F; A61F2/00; A61F2/02; A61F2/28; A61F2/30; A61F2/3094; A61F2/30942; A61L; A61L27/00; A61L27/40; A61L27/44; A61L27/46; B; B29; B29C; B29C64/00; B29C64/10; B29C64/141; B29C64/153; B29C64/165; B33; B33Y; B33Y70/00; B33Y80/00; C04B35/01; C04B35/447; C04B35/63; C04B35/632; C04B35/634; C04B35/63404; C04B35/63424; A61F2/2875; A61F2002/30001; A61F2002/30108; A61F2002/30199; A61F2/30767; A61F2002/30929; A61F2002/30952; A61F2002/30968; A61F2230/00; A61F2230/0063; A61F2310/00; A61F2310/00005; A61F2310/00179; A61F2310/00293; B29L; B29L2031/00; B29L2031/753; B29L2031/7532; B33Y10/00; C04B2235/00; C04B2235/02; C04B2235/30; C04B2235/32; C04B2235/3201; C04B2235/3205; C04B2235/3208; C04B2235/3212; C04B2235/36; C04B2235/50; C04B2235/54; C04B2235/5409; C04B2235/5418; C04B2235/5436; C04B2235/60; C04B2235/602; C04B2235/6026; C04B2235/608; C04B2235/61; C04B2235/616; C04B2235/65; C04B2235/658; C04B2235/6583; C04B2235/6584; C04B2235/66; C04B2235/665; C04B2235/70; C04B2235/74; C04B2235/77; C04B2235/80; C04B2235/96; C04B2235/9607; C04B2235/9615
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
55 words
A method for making an implant green part, comprising the steps of: (a) forming a mixture of a calcium phosphate composition and a polymer binder, wherein the calcium phosphate composition is calcium metaphosphate, calcium pyrophosphate, or mixtures thereof; and (b) selectively fusing the polymer binder with a laser beam to form the implant green part.
Claim 2
Independent Claim
55 words
A method for making an implant green part, comprising the steps of: (a) forming a mixture of a calcium phosphate composition and a polymer binder, wherein the calcium phosphate composition is calcium metaphosphate, calcium pyrophosphate, or mixtures thereof; and (b) selectively fusing the polymer binder with a laser beam to form the implant green part.
Claim 3
Dependent Claim
17 words
The method of claim 1, wherein the mixture comprises a plurality of agglomerated polymer-coated calcium phosphate particles.
Claim 4
Dependent Claim
25 words
The method of claim 2, wherein the polymer-coated particles are formed by spray drying an aqueous mixture of the calcium phosphate and the polymer binder.
Claim 5
Dependent Claim
18 words
The method of claim 1, further comprising the steps of infiltrating and thermally sintering the implant green part.
Claim 6
Dependent Claim
17 words
The method of claim 4, wherein the implant green part is infiltrated with a calcium phosphate solution.
Claim 7
Dependent Claim
16 words
The method of claim 1, further comprising the step of thermally sintering the implant green part.
Claim 8
Dependent Claim
19 words
The method of claim 6, further comprising the steps of infiltrating and again thermally sintering the implant green part.
Claim 9
Dependent Claim
17 words
The method of claim 7, wherein the implant green part is infiltrated with a calcium phosphate solution.
Claim 10
Dependent Claim
18 words
The method of claim 1, wherein the polymer binder is selectively fused to replicate a desired geometrical shape.
Claim 11
Dependent Claim
18 words
The method of claim 1, wherein the polymer binder is selectively fused to form a desired geometrical shape.
Claim 12
Dependent Claim
22 words
The method of claim 9 or claim 10, wherein the desired geometrical shape is communicated to the laser beam by a computer.
Claim 13
Dependent Claim
16 words
The method of claim 11, wherein the desired geometrical shape is obtained from computed tomographic data.
Claim 14
Dependent Claim
18 words
The method of claim 11, wherein the desired geometrical shape is obtained from computer aided design software data.
Claim 15
Dependent Claim
21 words
The method of claim 1, wherein the calcium phosphate composition is prepared by reacting aqueous solutions of hydroxyapatite and phosphoric acid.
Claim 16
Dependent Claim
34 words
The method of claim 1, wherein the calcium phosphate composition contains: from about 25 to about 45 percent by weight calcium oxide, or from about 0.5 to about 2 percent by weight sodium oxide.
Claim 17
Dependent Claim
12 words
The method of claim 1, wherein the calcium phosphate comprises calcium metaphosphate.
Claim 18
Dependent Claim
22 words
The method of claim 1, wherein the calcium phosphate has a mean particle size of from about 5 to about 100 microns.
Claim 19
Dependent Claim
22 words
The method of claim 1, wherein the calcium phosphate has a mean particle size of from about 30 to about 50 microns.
Claim 20
Dependent Claim
49 words
The method of claim 1, wherein the polymer binder has the following properties: (a) a T g of between about 40° C. and about 100° C.; and (b) a melt flow index of between about 1 and about 50 g/10 minutes at 200° C. and 75 psi extrusion pressure.
Claim 21
Dependent Claim
18 words
The method of claim 19, wherein the polymer binder comprises a homopolymer, copolymer, or terpolymer of methyl methacrylate.
Claim 22
Dependent Claim
15 words
The method of claim 20, wherein the polymer binder comprises a poly(methyl methacrylate-co-n-butyl methacrylate) copolymer.
Claim 23
Independent Claim
87 words
A method for making an implant green part, comprising the steps of: (a) forming a mixture of a calcium phosphate composition and a polymer binder, wherein the calcium phosphate composition is calcium metaphosphate, calcium pyrophosphate, or mixtures thereof; (b) forming a layer of the mixture; (c) selectively fusing the polymer binder with a laser beam; and (d) repeating steps (b) and (c) a desired number of times to form a plurality of layers, wherein each layer is fused to adjacent layers to form the implant green part.
Claim 24
Independent Claim
87 words
A method for making an implant green part, comprising the steps of: (a) forming a mixture of a calcium phosphate composition and a polymer binder, wherein the calcium phosphate composition is calcium metaphosphate, calcium pyrophosphate, or mixtures thereof; (b) forming a layer of the mixture; (c) selectively fusing the polymer binder with a laser beam; and (d) repeating steps (b) and (c) a desired number of times to form a plurality of layers, wherein each layer is fused to adjacent layers to form the implant green part.
Claim 25
Dependent Claim
22 words
The method of claim 22, wherein the thickness of each layer is from about 3 to about 12 thousandths of an inch.
Claim 26
Dependent Claim
23 words
The method of claim 22, wherein the implant green part has a mean pore size of from about 100 to about 300 microns.
Claim 27
Dependent Claim
21 words
The method of claim 22, wherein the implant green part has a relative density of from about 50 to about 80%.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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