Controlled architecture ceramic composites by stereolithography

• US 6,283,997 B1
• Filed: 11/13/1998
• Issued: 09/04/2001
• Est. Priority Date: 11/13/1998
• Status: Expired due to Fees

• Current Assignee: Ethicon Incorporated (Johnson & Johnson), United States Surgical Corporation (Medtronic Plc), The Trustees of Princeton University (Princeton University)
• Original Assignee: Ethicon Incorporated (Johnson & Johnson), The Trustees of Princeton University (Princeton University)
• Inventors: Garg, Rajeev, PrudʼHomme, Robert K., Aksay, Ilhan A., Huxel, Shawn T., TenHuisen, Kevor S., Janas, Victor F.
• Primary Examiner(s): McDermott, Corrine
• Assistant Examiner(s): Koh, Choon P.
• Application Number:
  US09/191,606
• Time in Patent Office: 1,026 Days
• Field of Search: 623/16, 623/23.51, 623/901, 623/23.56, 623/16.11, 430/269
• US Class Current: 623/16.11
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2/30942 for designing or making customized prostheses, e.g. using templates, CT or NMR scans, finite-element analysis or CAD-CAM techniques
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• CPC Class Codes: A61F 2002/2825 Femur
• CPC Class Codes: A61F 2002/2835 Bone graft implants for filling a bony defect or an endoprosthesis cavity, e.g. by synthetic material or biological material
• CPC Class Codes: A61F 2002/30011 differing in porosity
• CPC Class Codes: A61F 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30915 made of a stack of bonded perforated sheets, grids or wire meshes
• CPC Class Codes: A61F 2002/30948 using computerized tomography, i.e. CT scans
• CPC Class Codes: A61F 2002/30952 using CAD-CAM techniques or NC-techniques
• CPC Class Codes: A61F 2002/30962 using stereolithography
• CPC Class Codes: A61F 2002/30968 Sintering
• CPC Class Codes: A61F 2002/3097 using laser
• CPC Class Codes: A61F 2002/30971 Laminates, i.e. layered products
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2250/0023 differing in porosity
• CPC Class Codes: A61F 2310/00203 containing alumina or aluminium oxide
• CPC Class Codes: A61F 2310/00215 containing silica or silicon oxide
• CPC Class Codes: A61F 2310/00239 containing zirconia or zirconium oxide ZrO2
• CPC Class Codes: A61F 2310/00293 containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: A61F 2310/00317 : containing silicon nitride
• CPC Class Codes: A61L 27/02 : Inorganic materials
• CPC Class Codes: A61L 27/446 : with other specific inorganic fillers other than those covered by A61L27/443 or A61L27/46
• CPC Class Codes: B29C 64/135 : the energy source being concentrated, e.g. scanning lasers or focused light sources
• CPC Class Codes: B29K 2709/02 : Ceramics
• CPC Class Codes: B33Y 10/00 : Processes of additive manufacturing
• CPC Class Codes: B33Y 80/00 : Products made by additive manufacturing
• CPC Class Codes: C04B 2111/00836 : for medical or dental applications
• CPC Class Codes: C04B 35/00 : Shaped ceramic products characterised by their composition porous ceramic products C04B38/00; ceramic articles characterised by particular shape, see the relevant classes, e.g. linings for casting ladles, tundishes, cups or the like B22D41/02; ceramic substrates for microelectronic semi-conductors H01L23/15; Ceramics compositions containing free metal bonded to carbides, diamond, oxides, borides, nitrides, silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides or sulfides other than as macroscopic reinforcing agents C22C; shaping of ceramics B28B; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products chemical preparation of powders of inorganic compounds C01; infiltration of sintered ceramic preforms with molten metal C04B41/51
• CPC Class Codes: C04B 38/0054 : the pores being microsized or nanosized
• CPC Class Codes: C04B 38/067 : Macromolecular compounds C04B38/062 takes precedence; polysaccharides C04B38/0645
• CPC Class Codes: C04B 41/0036 : Laser treatment working by laser beam B23K26/00
• CPC Class Codes: G03F 7/0037 : Production of three-dimensional images
• CPC Class Codes: G05B 2219/49008 : Making 3-D object with model in computer memory
• CPC Class Codes: G05B 2219/49013 : Deposit layers, cured by scanning laser, stereo lithography SLA, prototyping
• CPC Class Codes: Y10S 623/901 : Method of manufacturing prosthetic device

Abstract

A process for producing a ceramic composite having a porous network. The process includes providing a photocurable ceramic dispersion. The dispersion consists of a photocurable polymer and a ceramic composition. The surface of the dispersion is scanned with a laser to cure the photocurable polymer to produce a photocured polymer/ceramic composition. The photocured composition useful as a polymer/ceramic composite, or the polymer phase can be removed by heating to a first temperature that is sufficient to burn out the photocured polymer. It is then heated to a second temperature that is higher than the first temperature and is sufficient to sinter the ceramic composition to produce a purely ceramic composition having a porous network.

Preferably and more specifically, the process uses a stereolithographic technique for laser scanning. The process can form a high quality orthopedic implant that dimensionally matches the bone structure of a patient. The technique relies upon laser photocuring a dense colloidal dispersion into a desired complex three-dimensional shape. The shape is obtained from a CAT scan file of a bone and is rendered into a CAD file that is readable by the stereolithography instrument. Or the shape is obtained directly from a CAD file that is readable by the stereolithography instrument.

Claims

1. A process for producing a ceramic composite bone implant having a porous network comprising:

providing a photocurable ceramic dispersion comprising a photocurable polymer and a high volume percent ceramic composition of alumina, silica, zirconia, barium titanate or silicon nitrite or mixtures thereof, the dispersion having an free fluid surface;

scanning the free fluid surface of the photocurable ceramic dispersion in a grid pattern with a laser to cure the photocurable polymer to produce a layer of photocured composition having a grid pattern;

scanning the free fluid surface of the photocurable ceramic dispersion in a grid pattern with a laser to cure the photocurable polymer to produce a second layer of photocured composition having a grid pattern, the grid patterns of the first and second layers being offset to form a porous network;

continuing to scan the free fluid surface of the photocurable ceramic dispersion in a grid pattern with a laser to cure subsequent layers of the photocurable polymer to produce subsequent layers of photocured composition with offset grid patterns;

removing uncured polymer and dispersion from the composition; and

drying or post-polymerization using UV or thermally curing the composition to produce a porous composite bone implant material which is suitable as a bone implant material or a device for orthopaedic implantation.

2. The process of claim 1 further comprising heating the photocured composition to a first temperature that is sufficient to burnout the photocured polymer, and then heating the composition to a second temperature that is higher than the first temperature and is sufficient to sinter the ceramic composition.

3. The process of claim 2 further comprising MRI scanning a bone to be duplicated to produce MRI data and converting the MRI data into three dimensional CAD image data and scanning the laser using the CAD image data.

4. The process of claim 1 wherein the photocurable polymer is biodegradable.

5. The process of claim 3 wherein the bone implant has pore sizes ranging from about 0.5 microns to 2000 microns and a porosity up to 75 percent.

6. A process for producing a ceramic composite bone implant having a porous network comprising:

providing a photocurable ceramic dispersion comprising a photocurable polymer and a high volume percent ceramic composition of alumina, silica, zirconia, barium titanate or silicon nitrite or mixtures thereof, the dispersion having an free fluid surface;

scanning the free fluid surface of the photocurable ceramic dispersion with a laser to cure the photocurable polymer to produce a photocured composition;

removing uncured polymer and dispersion from the composition;

incompletely drying or post-polymerization using UV or thermally curing the composition to produce a composite bone implant material which is suitable as a bone implant material or a device for orthopaedic implantation, the composite bone implant material having defects resulting from incompletely drying or curing the composition; and

partially sintering the composite bone implant material to form the defects into pores.

7. The process of claim 6 further comprising heating the photocured composition to a first temperature that is sufficient to burnout the photocured polymer, and then heating the composition to a second temperature that is higher than the first temperature and is sufficient to sinter the ceramic composition.

8. The process of claim 7 further comprising MRI scanning a bone to be duplicated to produce MRI data and converting the MRI data into three dimensional CAD image data and scanning the laser using the CAD image data.

9. The process of claim 6 wherein the photocurable polymer is biodegradable.

10. The process of claim 8 wherein the bone implant has pore sizes ranging from about 0.5 microns to 2000 microns and a porosity up to 75 percent.

11. A process for producing a ceramic composite bone implant having a porous network comprising:

providing a photocurable ceramic dispersion comprising a photocurable polymer and a high volume percent ceramic composition of hydroxyapatite or beta TCP or mixtures thereof, the dispersion having an free fluid surface;

scanning the free fluid surface of the photocurable ceramic dispersion in a grid pattern with a laser to cure the photocurable polymer to produce a layer of photocured composition having a grid pattern;

scanning the free fluid surface of the photocurable ceramic dispersion in a grid pattern with a laser to cure the photocurable polymer to produce a second layer of photocured composition having a grid pattern, the grid patterns of the first and second layers being offset to form a porous network;

continuing to scan the free third surface of the photocurable ceramic dispersion in a grid pattern with a laser to cure subsequent layers of the photocurable polymer to produce subsequent layers of photocured composition with offset grid patterns;

removing uncured polymer and dispersion from the composition; and

drying or post-polymerization using UV or thermally curing the composition to produce a porous composite bone implant material which is suitable as a bone implant material or a device for orthopaedic implantation.

12. The process of claim 11 further comprising heating the photocured composition to a first temperature that is sufficient to burnout the photocured polymer, and then heating the composition to a second temperature that is higher than the first temperature and is sufficient to sinter the ceramic composition.

13. The process of claim 12 further comprising MRI scanning a bone to be duplicated to produce MRI data and converting the MRI data into three dimensional CAD image data and scanning the laser using the CAD image data.

14. The process of claim 11 wherein the photocurable polymer is biodegradable.

15. The process of claim 13 wherein the bone implant has pore sizes ranging from about 0.5 microns to 2000 microns and a porosity up to 75 percent.

16. A process for producing a ceramic composite bone implant having a porous network comprising:

providing a photocurable ceramic dispersion comprising a photocurable polymer and a high volume percent ceramic composition of hydroxyapatite or beta TCP or mixtures thereof, the dispersion having an free fluid surface;

scanning the free fluid surface of the photocurable ceramic dispersion with a laser to cure the photocurable polymer to produce a photocured composition;

removing uncured polymer and dispersion from the composition; and

incompletely drying or post-polymerization using UV or thermally curing the composition to produce a composite bone implant material which is suitable as a bone implant material or a device for orthopaedic implantation, the composite bone implant material having defects resulting from incompletely drying or curing the composition; and

partially sintering the composite bone implant material to form the defects into pores.

17. The process of claim 16 further comprising heating the photocured composition to a first temperature that is sufficient to burnout the photocured polymer, and then heating the composition to a second temperature that is higher than the first temperature and is sufficient to sinter the ceramic composition.

18. The process of claim 17 further comprising MRI scanning a bone to be duplicated to produce MRI data and converting the MRI data into three dimensional CAD image data and scanning the laser using the CAD image data.

19. The process of claim 16 wherein the photocurable polymer is biodegradable.

20. The process of claim 18 wherein the bone implant has pore sizes ranging from about 0.5 microns to 2000 microns and a porosity up to 75 percent.