Deposition of discrete nanoparticles on an implant surface

• US 20070110890A1
• Filed: 11/13/2006
• Published: 05/17/2007
• Est. Priority Date: 11/14/2005
• Status: Active Grant

• Current Assignee: Biomet 3i LLC (Zimvie Incorporated)
• Original Assignee: Biomet 3i LLC (Zimvie Incorporated)
• Inventors: Berckmans, Bruce, Towse, Ross, Mayfield, Robert
• Granted Patent: US 7,771,774 B2
• Time in Patent Office: Days
• US Class Current: 427/2.240
• CPC Class Codes: A61B 17/866 Material or manufacture
• CPC Class Codes: A61C 2008/0046 Textured surface, e.g. roughness, microstructure A61C8/0013 takes precedence
• CPC Class Codes: A61C 8/0006 Periodontal tissue or bone regeneration support means for endoprosthetic bone substitute or bone graft implants A61F2/2846
• CPC Class Codes: A61C 8/0012 characterised by the material or composition, e.g. ceramics, surface layer, metal alloy use of specific materials A61K6/00
• CPC Class Codes: A61C 8/0013 with a surface layer, coating
• CPC Class Codes: A61C 8/0015 being a conversion layer, e.g. oxide layer
• CPC Class Codes: A61C 8/0022 Self-screwing A61C8/0028 takes precedence
• CPC Class Codes: A61F 2/0077 Special surfaces of prostheses, e.g. for improving ingrowth A61F2/30767 takes precedence
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/30771 applied in original prostheses, e.g. holes or grooves
• CPC Class Codes: A61F 2002/30925 etched
• CPC Class Codes: A61F 2310/00017 Iron- or Fe-based alloys, e.g. stainless steel
• CPC Class Codes: A61F 2310/00023 Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00029 Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium
• CPC Class Codes: A61F 2310/00059 Chromium or Cr-based alloys
• CPC Class Codes: A61F 2310/00131 Tantalum or Ta-based alloys
• CPC Class Codes: A61F 2310/00796 Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite
• CPC Class Codes: A61K 6/838 Phosphorus compounds, e.g. apatite
• CPC Class Codes: A61K 6/84 comprising metals or alloys
• CPC Class Codes: A61L 2400/12 Nanosized materials, e.g. nanofibres, nanoparticles, nanowires, nanotubes; Nanostructured surfaces
• CPC Class Codes: A61L 27/06 : Titanium or titanium alloys
• CPC Class Codes: A61L 27/10 : Ceramics or glasses
• CPC Class Codes: A61L 27/32 : Phosphorus-containing materials, e.g. apatite
• CPC Class Codes: C23C 22/03 : containing phosphorus compounds
• CPC Class Codes: C23C 26/00 : Coating not provided for in groups C23C2/00 - C23C24/00
• CPC Class Codes: C23C 30/00 : Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process C23C26/00, C23C28/00 take precedence
• CPC Class Codes: C23G 1/106 : refractory metals

Abstract

A method of forming an implant to be implanted into living bone is disclosed. The method comprises the act of roughening at least a portion of the implant surface to produce a roughened surface. The method further comprises the act of depositing discrete nanoparticles on the roughened surface though a one-step process of exposing the roughened surface to a solution. The nanoparticles comprise a material having a property that promotes osseointegration.

Claims

1. A method of forming an implant to be implanted into living bone, the method comprising the acts of:

roughening at least a portion of the implant surface to produce a microscale roughened surface; and

depositing discrete nanoparticles on the roughened surface though a one-step process of exposing the roughened surface to a solution including the nanoparticles, the nanoparticles comprising a material having a property that promotes osseointegration.

2. The method of claim 1, wherein the implant is made of a metal selected from the group consisting of tantalum, cobalt, chromium, titanium, stainless steel, or alloys thereof.

3. The method of claim 2, wherein the metal comprises titanium.

4. The method of claim 1, wherein the implant is made from a material including ceramic.

5. The method of claim 1, wherein the implant is a dental implant.

6. The method of claim 5, wherein the portion of the implant surface is a threaded bottom portion for facilitating bonding with bone.

7. The method of claim 1, wherein the implant is made of titanium and the act of roughening the implant surface comprises:

removing a native oxide layer from the implant surface; and

acid etching the resulting surface.

8. The method of claim 1, wherein the act of roughening the implant surface creates irregularities, the irregularities having peak-to-valley heights not greater than about 20 microns.

9. The method of claim 8, wherein the nanoparticles include hydroxyapatite nanocrystals having dimensions of about 20 nanometers to about 100 nanometers.

10. The method of claim 9, wherein the solution further includes a 2-methoxyethanol solvent.

11. The method of claim 10, wherein the act of depositing the hydroxyapatite nanocrystals further comprises adjusting the pH of the solution.

12. The method of claim 11, wherein the adjusting the pH of the solution includes using ammonium hydroxide.

13. The method of claim 11, wherein the pH is adjusted to between about 9 and about 11.

14. The method of claim 10 further comprising, after the depositing step, the act of rinsing the implant in reverse osmosis/deionized water.

15. The method of claim 14 further comprising thermally curing the implant to sinter the deposited hydroxyapatite nanocrystals.

16. The method of claim 14 further comprising the acts of:

rinsing the implant in deionized water; and

drying the implant.

17. The method of claim 14, wherein prior to depositing the hydroxyapatite nanocrystals, the method comprises rinsing the implant in deionized water.

18. A method of forming a dental implant made of a titanium or titanium alloy, the method comprising the acts of:

etching at least a threaded bottom portion of the implant to remove a native oxide layer;

acid etching the threaded bottom portion to form a roughened surface having a substantially uniform array of microscale irregularities having peak-to-valley heights not greater than about 20 microns; and

without pretreating the roughened surface, depositing discrete hydroxyapatite nanocrystals on the roughened surface by exposure to a solution comprising 2-methoxyethanol solvent and the hydroxyapatite nanocrystals.

19. The method of claim 18, wherein the irregularities have a peak-to-valley height of from about 1 micron to about 10 microns.

20. The method of claim 19, wherein the etching, acid etching, and roughening occurs on all surfaces that will be in contact with bone or gingiva.

21. The method of claim 18 further comprising, prior to the exposure to the solution, adjusting the pH of the solution.

22. The method of claim 21, wherein the adjusting the pH of the solution includes using ammonium hydroxide.

23. The method of claim 21, wherein the pH is adjusted to between about 9 and about 11.

24. The method of claim 18, wherein the hydroxyapatite nanocrystals have dimensions of about 20 nanometers to about 100 nanometers.

25. The method of claim 18, further including one or more cleaning or rinsing steps after the acid-etching step and prior to depositing the hydroxyapatite nanocrystals.

26. The method of claim 25, wherein the rinsing step includes rinsing the implant in deionized water.

27. The method of claim 18 further comprising the act of rinsing the implant in reverse osmosis/deionized water.

28. The method of claim 27 further comprising the act of thermally curing the implant to sinter the deposited hydroxyapatite nanocrystals.

29. The method of claim 27 further comprising the acts of:

rinsing the implant in deionized water; and

drying the implant.

30. The method of claim 18, wherein the irregularities include cone-shaped elements.

31. The method of claim 18, wherein the native oxide layer is removed by a first acid solution.

32. The method of claim 31, wherein the first acid solution is aqueous hydrofluoric acid and the act of acid etching includes a mixture of sulfuric and hydrochloric acids.

33. A method of forming an implant to be implanted into living bone, the method comprising the act of depositing discrete nanoparticles on the surface of the implant though a one-step process of exposing the surface to a solution, the nanoparticles comprising a material having a property that promotes osseointegration.

34. The method of claim 33, wherein the implant is made of titanium.

35. The method of claim 33, wherein the implant is made of a material including ceramic.

36. A method of forming an implant to be implanted into living bone, the method comprising the acts of:

providing an implant;

depositing discrete nanoparticles on the surface of the implant though a one-step process of exposing the surface to a solution, the nanoparticles comprising a material having a property that promotes osseointegration;

rinsing the implant; and

drying the implant.