Porous laser sintered articles

• US 8,142,886 B2
• Filed: 07/24/2008
• Issued: 03/27/2012
• Est. Priority Date: 07/24/2007
• Status: Active Grant

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Inventors: Mao, Guoqiang, Henry, Sebastien P., Noble, Aaron M.
• Primary Examiner(s): Vo, Hai
• Application Number:
  US12/179,287
• Publication Number:
  US 20090068245A1
• Time in Patent Office: 1,342 Days
• Field of Search: 428/315.5, 428/315.7, 428/316.6, 428/318.4, 428/317.9, 623/23.76, 623/23.51, 623/17.16, 264/497
• US Class Current: 428/316.6
• CPC Class Codes: A61F 2/2875 Skull or cranium A61F2/2803 and A61F2/3099 take precedence
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• 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 2002/2889 Maxillary, premaxillary or molar implants
• CPC Class Codes: A61F 2002/30011 differing in porosity
• CPC Class Codes: A61F 2002/30948 using computerized tomography, i.e. CT scans
• 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 2250/0023 differing in porosity
• CPC Class Codes: A61F 2250/0024 made from both porous and non-porous parts, e.g. adjacent parts
• CPC Class Codes: A61F 2310/00353 Bone cement, e.g. polymethylmethacrylate or PMMA
• CPC Class Codes: A61L 27/16 obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61L 27/446 with other specific inorganic fillers other than those covered by A61L27/443 or A61L27/46
• CPC Class Codes: A61L 27/46 with phosphorus-containing inorganic fillers
• CPC Class Codes: A61L 27/56 Porous materials, e.g. foams or sponges
• CPC Class Codes: B22F 10/28 Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
• CPC Class Codes: B22F 10/38 to achieve specific product aspects, e.g. surface smoothness, density, porosity or hollow structures
• CPC Class Codes: B22F 2998/00 Supplementary information concerning processes or compositions relating to powder metallurgy
• CPC Class Codes: B22F 3/1103 with particular physical characteristics
• CPC Class Codes: B29C 64/153 : using layers of powder being selectively joined, e.g. by selective laser sintering or melting
• CPC Class Codes: B29C 67/205 : comprising surface fusion, and bonding of particles to form voids, e.g. sintering
• CPC Class Codes: B29L 2031/7532 : Artificial members, protheses
• CPC Class Codes: B33Y 70/10 : Composites of different types of material, e.g. mixtures of ceramics and polymers or mixtures of metals and biomaterials
• CPC Class Codes: B33Y 80/00 : Products made by additive manufacturing
• CPC Class Codes: C08L 23/02 : not modified by chemical after-treatment
• CPC Class Codes: Y02P 10/25 : Process efficiency
• CPC Class Codes: Y10T 428/249961 : With gradual property change within a component
• CPC Class Codes: Y10T 428/249978 : Voids specified as micro
• CPC Class Codes: Y10T 428/249979 : Specified thickness of void-containing component [absolute or relative] or numerical cell dimension
• CPC Class Codes: Y10T 428/249981 : Plural void-containing components
• CPC Class Codes: Y10T 428/249986 : Void-containing component contains also a solid fiber or solid particle
• CPC Class Codes: Y10T 428/249987 : With nonvoid component of specified composition

Abstract

The present invention provides selectively laser sintered porous polymeric articles and methods of making and using the same. In one embodiment, a method of the present invention comprises providing a first layer of particles of a first polymeric material, heating selected locations of the first layer to sinter particles of the first polymeric material to form a three-dimensional article, the three-dimensional article having a porosity of at least about 30 percent.

Claims

1. A laser sintered porous polymeric article comprising:

a core having a first polymeric material, a first porosity, and a first amount of inorganic material;

an outer surface layer at least partially enveloping the core, the outer surface layer having a second polymeric material, a second porosity, and a second amount of inorganic material; and

an intermediary layer including a third polymeric material and being disposed between the outer surface layer and the core, the intermediary layer having both a porosity gradient and a compositional gradient, the porosity gradient having a range of porosities extending between the first porosity and the second porosity and the compositional gradient having a range of amounts of inorganic material extending between the first amount of inorganic material and the second amount of inorganic material,

wherein the core is substantially non-porous and the outer surface layer is substantially porous,

wherein the second amount of inorganic material is greater than the first amount of inorganic material, and

wherein the inorganic material comprises a mixture of at least two components selected from the group consisting of a metal, metal alloy, calcium phosphate, stainless steel and glass.

2. The laser sintered porous polymeric article of claim 1, wherein at least one of the first, second, and third polymeric materials comprises a polyolefin.

3. The laser sintered porous polymeric article of claim 2, wherein the polyolefin comprises polyethylene, polypropylene, or copolymers thereof.

4. The laser sintered porous polymeric article of claim 3, wherein the polyethylene comprises high density polyethylene, ultrahigh molecular weight polyethylene, or mixtures thereof.

5. The laser sintered porous polymeric article of claim 1, wherein the porosity of the outer surface layer is at least 20 percent.

6. The laser sintered porous polymeric article of claim 1, wherein the article is an implant.

7. The laser sintered porous polymeric article of claim 6, wherein the implant is a craniofacial implant or a maxillofacial implant.

8. The laser sintered porous polymeric article of claim 1, wherein the article comprises an interconnected pore structure.

9. A method of producing the laser sintered porous polymeric article of claim 1 comprising the steps of:

providing a first layer of particles of the first polymeric material, the first layer of particles including the first amount of inorganic material;

providing a second layer of particles of the second polymeric material, the second layer of particles including the second amount of inorganic material;

successively providing additional layers of particles of the third polymeric material, the successive layers of particles including the range of amounts of inorganic material which extend between the first amount of inorganic material and the second amount of inorganic material;

heating selected locations of the first, second, and additional layers to sinter particles of the first, second, and third polymeric materials to form a three dimensional article,

wherein the core of the article comprises the first layer of particles, the outer surface layer comprises the second layer of particles, and the intermediary layer comprises the additional layers of particles, and

wherein the three dimensional article has a porosity of at least about 20 percent.

10. The method of claim 9, wherein heating comprises exposing the selected locations to electromagnetic radiation.

11. The method of claim 10, wherein the electromagnetic radiation comprises visible radiation, infrared radiation, or combinations thereof.

12. The method of claim 9, wherein the three dimensional article has an average pore size of at least about 20 μ

m.

13. The method of claim 9, wherein the three-dimensional article comprises an implant.

14. The method of claim 13, wherein the implant comprises a craniofacial implant or a maxillofacial implant.

15. The method of claim 9, wherein the three dimensional article comprises an interconnected pore structure.

16. An implant comprising:

a first region having a first polymeric material, a first porosity, and a first amount of inorganic material, wherein the combination of the first porosity and the first amount of inorganic material promotes bone in-growth;

a second region having a second polymeric material, a second porosity, and a second amount of inorganic material, wherein the combination of the second porosity and the second amount of inorganic material resists bone in-growth; and

a third region including a third polymeric material and having both a porosity gradient and a compositional gradient, the porosity gradient having a range of porosities extending between the first porosity and the second porosity and the compositional gradient having a range of amounts of inorganic material extending between the first amount of inorganic material and the second amount of inorganic material,

wherein the compositional gradient has a higher amount of inorganic material in regions adjacent to bone tissue and a lower amount of inorganic material in regions distal to bone tissue,

wherein the first amount of inorganic material in the first region is higher than the second amount of inorganic material in the second region in order to promote tissue compatibility between the first region and an adjacent region of bone,

wherein the second region is substantially non-porous and the first region has a higher porosity than the second region, and

wherein the inorganic material comprises a mixture of at least two components selected from the group consisting of a metal, metal alloy, calcium phosphate, stainless steel, and glass.

17. The implant of claim 16, wherein at least one of the first and second regions has an average pore size of at least about 20 μ

m.

18. The implant of claim 16, wherein at least one of the first and second regions has an average pore size ranging from about 10 μ

m to about 1 mm.

19. The implant of claim 16, wherein the inorganic material of at least one of the first, second, and third regions is present in an amount up to about 30 weight percent of the implant.

20. The implant of claim 16, wherein the second region is a core of the implant.

21. The implant of claim 16, wherein the first porosity of the first region is at least 20 percent.

22. A method of treating a patient in need of the implant of claim 16 comprising the steps of:

creating a three-dimensional image of the implant area;

converting the three-dimensional image into a format compatible with a selective laser sintering apparatus;

providing a first layer of particles of the first polymeric material, the first layer of particles including the first amount of inorganic material;

providing a second layer of particles of the second polymeric material, the second layer of particles including the second amount of inorganic material;

successively providing additional layers of particles of the third polymeric material, the successive layers of particles including the range of amounts of inorganic material which extend between the first amount of inorganic material and the second amount of inorganic material;

heating locations of the first, second, and additional layers according to the three-dimensional image to sinter particles of the first, second, and third polymeric materials to form a three dimensional implant,

wherein the first region of the implant comprises the first layer of particles, the second region comprises the second layer of particles, and the third region comprises the additional layers of particles, the three dimensional implant having a porosity of at least about 20 percent; and

implanting the three-dimensional implant into the implant area.

23. The method of claim 22, wherein the implant has an average pore size of at least about 20 μ

m.

24. The method of claim 22, wherein the implant comprises a multidirectional and interconnected pore structure.

25. The method of claim 22, wherein the implant comprises a craniofacial implant or a maxillofacial implant.