Claims
- 1. A combination dense/porous structure, comprising:
a porous element having an outer surface defining a shape having a bulk volume, the element comprising a continuous framework having struts defining a plurality of interconnecting interstices throughout the bulk volume, and said porous element having interconnecting interstices extending throughout said volume and openings through said surface; a ceramic or metal dense element formed from a material and having a sintered density of at least 95% contacting at least a portion of the porous element; and an interconnection zone formed by the inter-penetration of the material forming the dense element into the porous element.
- 2. A combination dense/porous structure according to claim 1, wherein the bulk volume has an inward facing surface and the dense portion contacts at least a portion of the inward facing surface.
- 3. A combination dense/porous structure according to claim 1, wherein the porous and dense elements comprise a ceramic.
- 4. A combination dense/porous structure according to claim 1, wherein the porous element has a porosity of 80% or greater.
- 5. A combination dense/porous structure according to claim 1, wherein the continuous framework having struts defining a plurality of interconnecting interstices have 3-3 connectivity.
- 6. A combination dense/porous structure according to claim 1, wherein the average interstices are wider than the thicknesses of the struts.
- 7. A combination dense/porous structure according to claim 1 formed by a process comprising:
providing a porous element in a green state; providing a first dispersion of a ceramic or metal powder, a binder, and a solvent to form a slip; contacting a slip with a least a portion of the porous element whereby the slip at least partially penetrates into at least a portion of the porous element to form an interconnection zone and a dense element adjacent to the interconnection zone; sintering the combination dense/porous structure.
- 8. A combination dense/porous structure according to claim 7, wherein the porous and dense elements comprise a ceramic.
- 9. A bone substitute material comprising a combination dense/porous structure according to claim 1.
- 10. A method of generating bone to an area in need of bone comprising:
providing the bone substitute material according to claim 9; positioning the porous element into the area in need of bone and adjacent to living bone to provide bone in-growth into the porous element; and stabilizing the porous element with the dense element.
- 11. A method of generating bone according to claim 10, wherein the stabilizing comprises connecting the dense element to natural bone to anchor the bone substitute material.
- 12. A process for producing a combination dense/porous structure according to claim 1 comprising:
(a) providing a porous element in a green state; (b) providing a dispersion comprising a ceramic or metal powder and a binder; (c) contacting the dispersion with the porous element whereby the slip at least partially penetrates into at least a portion of the porous element to form an interconnection zone and a dense element formed from the dispersion and adjacent to the interconnection zone to form a combination dense/porous structure; (d)solidifying the dense/porous structure to form a green combination dense/porous structure; and (e) sintering the green dense/porous structure to form the combination dense/porous structure.
- 13. A process according to claim 12, wherein the process of providing the porous element in a green state comprises
(a) providing a first dispersion comprising a ceramic or metal powder, a binder, and a solvent to form a slip; (b) providing a reticulated substrate which has open, interconnected porosity. (c) contacting the reticulated substrate with the slip to coat the substrate with the dispersion to form a first coating; (d) optionally applying subsequent multiple coatings of the same or different slip, and (e) drying the coated reticulated substrate to form the green porous element.
- 14. An injection molding process for producing a combination dense/porous structure according to claim 1 comprising:
(a) providing a porous element in a green state; (b) inserting the porous element into a mold; (c) providing a first dispersion comprising a ceramic or metal powder and a binder, form a feedstock; (d) injection molding the feedstock into the tool for a time and pressure sufficient to force the feedstock into at least a portion of the porous element to form a molded green dense/porous structure; (e) removing the molded green dense/porous structure from the tool; (f) debinding the molded structure; and (g) sintering the molded green combination dense/porous structure to form the combination dense/porous structure.
- 15. A process according to claim 14, wherein the tool cavity has at least one dimension larger than a corresponding dimension of the porous element.
- 16. A process according to claim 14, wherein the step of injection molding the feedstock compresses the porous green element into a volume smaller than the uncompressed volume of the porous element, and the step of debinding the molded green dense/porous structure expands the porous green element, such that the sintered dense/porous structure has a dimension larger than a corresponding dimension of the tool cavity.
- 17. A process according to claim 14, further comprising:
filling at least a portion of the interstices of the green porous element with a material that maintains the shape of the green porous element during injection molding; and removing the material from the green porous element such that the dimensions of the green porous element remain substantially identical to the dimensions before injection molding.
- 18. A process according to claim 17, wherein the material is a wax and the removal of the material from the green porous element comprises applying a solvent to the green porous element.
- 19. A process according to claim 17, wherein the material is a polymer and the removal of the material from the green porous element comprises applying a solvent to the green porous element.
- 20. A process according to claim 17, wherein the material is a salt and the removal of the material from the green porous element comprises applying a solvent to the green porous element.
- 21. A process according to claim 17, wherein the material is a wax and the removal of the material from the green porous element comprises applying heat to the green porous element.
- 22.A process according to claim 17, wherein the material is a polymer and the removal of the material from the green porous element comprises applying heat to the green porous element.
- 23. A process according to claim 17, wherein the material is a salt and the removal of the material from the green porous element comprises applying heat to the green porous element.
- 24. A process according to claim 14, wherein the porous element in a green state includes channels for accommodating the feedstock flow front as the tool cavity is filled.
- 25. A slip casting process for producing a combination dense/porous structure according to claim 1, comprising:
(a) providing a porous mold; (b) providing a first dispersion of a ceramic or metal powder, a binder, and a solvent to form a slip; (c) pouring the slip into the mold, whereby the solvent in the slip is removed through the mold by capillary action to form a green dense element; (d) optionally adding additional slip to adjust one or more dimensions of the dense element; (e) providing a green porous element; (g) contacting the green porous element with the dense green element while at least one surface of the dense element is wet with slip; (h) drying to form a green dense/porous structure; (i) removing the green dense/porous structure; and (j) sintering the dense/porous structure to form the combination dense/porous structure.
- 26. A process according to claim 25, further comprising removing excess slip from the mold when a desired dimension is reached and wherein the wet slip on the at least one surface of the dense element is from the slip used to form the solid element.
- 27.A process according to claim 25, further comprising adding additional slip to retain minimum wet slip for providing an interconnection zone between the porous and dense element.
- 28. A process for producing a combination dense/porous structure according to claim 1, comprising:
(a) providing a porous element in a green state; (b) providing a first dispersion of a ceramic or metal powder, a binder, and a solvent to form a slip; (c) coating at least a portion of one surface of the porous element with the slip whereby the slip at least partially penetrates into at least a portion of the porous element to form the interconnection zone and a dense element is formed from the slip and adjacent to the interconnection zone to provide a dense/porous structure; (d) optionally adding further coats of slip to the porous element; (e) drying the combination dense/porous structure to form a green dense/porous structure; and (f) sintering the green dense/porous structure to form a combination dense/porous structure.
- 29. A process according to claim 28, wherein the coating at least one surface comprises brushing the slip onto the at least one surface.
- 30. A combination dense/porous structure useful as an artificial bone structure comprising an element having a shape of natural bone or a portion of natural bone and a cross-section that comprises the combination dense/porous structure according to claim 1 having
an inner porous portion formed from the porous element to mimic the cancellous structure of bone; and an outer dense portion completely surrounding the inner porous portion formed from the dense element to mimic the cortical structure of bone.
- 31.A combination dense/porous structure useful as an artificial bone structure as claimed in claim 30 in the shape of a replacement for a segment of long bone.
- 32. A combination dense/porous structure useful as an artificial bone structure as claimed in claim 30 in the shape of the metaphyseal or diaphyseal segment of a bone.
- 33. A combination dense/porous structure useful as an artificial bone structure as claimed in claim 30 in the shape of an entire bone.
- 34. A combination dense/porous structure useful as an artificial bone structure as claimed in claim 30 in the shape of a vertebral body.
- 35. A combination dense/porous structure useful as an artificial bone structure comprising the bone substitute material as claimed in claim 9, wherein the porous element mimics the cancellous structure of natural bone, and
wherein the dense portion mimics the cortical structure of bone.
- 36. A combination dense/porous structure useful as an artificial bone structure comprising the bone substitute material as claimed in claim 9, wherein one or more dense elements are surrounded by a porous element configured for use in fusing two adjacent bone segments together.
- 37. A combination dense/porous structure useful as an artificial bone structure comprising the bone substitute material as claimed in claim 9, wherein one or more dense elements are surrounded by a porous element configured for use in the spinal column to achieve fusion of two adjacent vertebrae.
- 38. A combination dense/porous structure useful as an artificial bone structure comprising the bone substitute material as claimed in claim 9, wherein a dense element surrounds a porous element and contains holes exposing the porous element to the outer surface of the dense element.
- 39.A combination dense/porous structure useful as an artificial bone structure comprising the bone substitute material as claimed in claim 9, wherein a cylindrical dense element surrounds a porous element and contains holes exposing the porous element to the outer surface of the dense element in a configuration suitable for use in the spinal column to achieve fusion of two adjacent vertebrae.
- 40. A method of regenerating bone to an area in need of bone comprising:
providing a bone substitute material having a dense element and a porous element; positioning the porous element into the area in need of bone and adjacent to living bone to provide bone in-growth into the porous element; and stabilizing the porous element with the dense element.
- 41. A method of regenerating bone according to claim 40, wherein the stabilizing comprises connecting the dense element to natural bone to anchor the bone substitute material.
- 42. A combination dense/porous structure useful as a sustained release delivery system comprising:
a reticulated, porous element having an open interconnected porosity; and a dense, element surrounding at least a portion of the porous element, wherein at least one of the dense or porous element contains a physiologically active agent.
- 43. A sustained release delivery system according to claim 42, wherein the porous element contains the physiologically active agent.
- 44. A sustained release delivery system according to claim 42, wherein porous element has an outer surface defining a shape having a bulk volume, the element comprising a continuous framework having struts defining a plurality of interconnecting interstices throughout the bulk volume, and said porous element having interconnecting interstices extending throughout said volume and openings through said surface
- 45. A sustained release delivery system according to claim 42, wherein the average interstices are wider than the thicknesses of the struts.
- 46. A sustained release delivery system according to claim 43, wherein the dense element surrounds a portion of the porous element and the delivery of the physiologically active agent from the porous element is controlled by the thickness of dense element surrounding the porous element.
- 47. A sustained release delivery system according to claim 43, wherein the dense element surrounds a portion of the porous element and the delivery of the physiologically active agent from the porous element is controlled by the surface area of the porous element that is covered by the dense element.
- 48. A sustained release delivery system according to claim 43, wherein the dense element is a bioresorbable material and the delivery of the physiologically active agent from the porous element is controlled by the bioabsorption of the dense element.
- 49. A sustained release delivery system according to claim 42, wherein the porous element and dense element comprise a ceramic.
- 50. A combination dense/porous structure, comprising:
a porous element having an outer surface defining a shape having a bulk volume, the element comprising a continuous framework having struts defining a plurality of interconnecting interstices throughout the bulk volume, and said porous element having interconnecting interstices extending throughout said volume and opening through said surface; a ceramic or metal dense element formed from a material and having a sintered density of at least 95% contacting at least a portion of the porous element; a bonding phase; and an interconnection zone joining at least one surface of the porous element and dense element whereby the bonding phase penetrates into the porous element.
- 51. A combination dense/porous structure according to claim 50, wherein the average interstices are wider than the thicknesses of the struts.
- 52. A process for producing a combination dense/porous structure according to claim 50 comprising:
(a) providing a porous element having an outer surface defining a shape having a bulk volume, the element comprising a framework having struts defining a plurality of interconnecting interstices throughout the bulk volume, and said article having interconnecting interstices extending throughout said volume and opening through said surface; (b) providing a dense element formed from a material and having a sintered density of at least 95%; (c) providing a bonding phase; (d) joining at least one surface of the porous element and the dense element with the bonding phase, whereby the bonding phase penetrates into the porous element and forms an interconnection zone; (e) drying the bonding phase to form the combination dense/porous structure; and (f) sintering the combined dense and porous element with the interconnection zone to form the combination dense/porous structure.
- 53. A process for producing a combination dense/porous structure according to claim 52, wherein the bonding phase comprises a dispersion of a ceramic or metal powder, a binder, and a solvent in the form of a slip.
- 54. A combination dense/porous structure, comprising:
a sintered porous element having an outer surface defining a shape having a bulk volume, the element comprising a continuous framework having struts defining a plurality of interconnecting interstices throughout the bulk volume, and said sintered porous element having interconnecting interstices extending throughout said volume and opening through said surface; sintered metal or ceramic dense element formed from a material and having a sintered density of at least 95% contacting at least a portion of the porous element; a bonding phase; and an interconnection zone joining at least one surface of the porous element and dense element whereby the bonding phase penetrates into the porous element.
- 55. A combination dense/porous structure according to claim 54, wherein the average interstices are wider than the thicknesses of the struts.
- 56. A process for producing a combination dense/porous structure according to claim 54 comprising:
(a) providing a sintered porous element having an outer surface defining a shape having a bulk volume, the element comprising a framework having struts defining a plurality of interconnecting interstices throughout the bulk volume, and said sintered porous element having interconnecting interstices extending throughout said volume and opening through said surface; (b) providing a sintered dense element formed from a material and having a sintered density of at least 95%; (c) providing a bonding phase; (d) joining at least one surface of the sintered porous element and the sintered dense element with the bonding phase, whereby the bonding phase penetrates into the porous element and forms an inter-penetration zone; and (e) curing, drying, and/or heating, if necessary, the bonding phase to form the combination dense/porous structure.
- 57. A process for producing a combination dense/porous structure according to claim 56, wherein the bonding phase comprises a dispersion of a ceramic or metal powder, a binder, and a solvent in the form of a slip.
- 58. A combination dense/porous structure according to claim 1, wherein the combination dense/porous structure is produced by a process, comprising:
(a) providing a porous element in a green state; (b) providing a dispersion comprising a ceramic or metal powder and a binder; (c) contacting the dispersion with the porous element whereby the slip at least partially penetrates into at least a portion of the porous element to form an interconnection zone and a dense element formed from the dispersion and adjacent to the interconnection zone to form a combination dense/porous structure; (d) solidifying the combination dense/porous structure to form a green combination dense/porous structure; and (e) sintering the green combination dense/porous structure to form the combination dense/porous structure.
- 59. A combination dense/porous structure according to claim 49, wherein the combination dense/porous structure is produced by a process comprising:
providing a porous element; providing a ceramic or metal dense element formed from a material and having a sintered density of at least 95%; providing a bonding phase; joining at least one surface of the porous element and the dense element with the bonding phase, whereby the bonding phase penetrates into the porous element and forms an interconnection zone; drying the bonding phase to form the combination dense/porous structure; and sintering the combined dense and porous element with the interconnection zone to form the combination dense/porous structure.
- 60. A combination dense/porous structure according to claim 54, wherein the combination dense/porous structure is produced by a process comprising:
providing a sintered porous element; providing a sintered ceramic or metal dense element formed from a material and having a sintered density of at least 95%; providing a bonding phase; joining at least one surface of the sintered porous element and the sintered dense element with the bonding phase, whereby the bonding phase penetrates into the porous element and forms an interconnection zone; and (e) curing, drying, and/or heating, if necessary, the bonding phase to form the combination dense/porous structure.
- 61. A method for sustained release of a physiologically active agent in a selected direction comprising:
providing a reticulated, porous element having an open interconnected porosity containing a physiologically active agent; surrounding a portion of the porous element with a dense element; and exposing the porous element in directions where release of the physiologically active agent is selected.
- 62. A method for sustained release of a physiologically active agent in a selected direction as claimed in claim 61, wherein the physiologically active agent comprises BMP.
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to provisional application No. 60/283,752, filed on Apr. 16, 2001, which is incorporated by reference in its entirety.
Provisional Applications (1)
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Number |
Date |
Country |
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60283752 |
Apr 2001 |
US |