Osseointegrative surgical implant

Abstract

Embodiments of the present invention provide an osseointegrative implant and related tools, components and fabrication techniques for surgical bone fixation and dental restoration purposes. In one embodiment an all-ceramic single-stage threaded or press-fit implant is provided having finely detailed surface features formed by ceramic injection molding and/or spark plasma sintering of a powder compact or green body comprising finely powdered zirconia. In another embodiment a two-stage threaded implant is provided having an exterior shell or body formed substantially entirely of ceramic and/or CNT-reinforced ceramic composite material. The implant may include one or more frictionally anisotropic bone-engaging surfaces. In another embodiment a densely sintered ceramic implant is provided wherein, prior to sintering, the porous debound green body is exposed to ions and/or particles of silver, gold, titanium, zirconia, YSZ, α-tricalcium phosphate, hydroxyapatite, carbon, carbon nanotubes, and/or other particles which remain lodged in the implant surface after sintering. Optionally, at least the supragingival portions of an all-ceramic implant are configured to have high translucence in the visible light range. Optionally, at least the bone-engaging portions of an all-ceramic implant are coated with a fused layer of titanium oxide.

1 . A threaded ceramic implant produced by a manufacturing process comprising:
 injecting a powdered ceramic feedstock into a mold cavity, said powdered ceramic feedstock comprising a colloidal mixture of ultrafine powdered zirconia suspended in a heated liquid binder, said mold cavity comprising at least one female thread;   causing or allowing said injected feedstock to cool in said mold cavity such that it forms a substantially solid green body having at least one mating male thread corresponding to said at least one female thread;   removing said green body from said mold at least in part by rotating and unscrewing said green body from said mold;   debinding said green body so as to remove a majority of said binder; and   sintering said debound green body so as to form said threaded ceramic osseointegrative dental implant.   
     
     
         2 . The threaded ceramic implant of  claim 1  wherein said powdered ceramic feedstock comprises powdered 3-mol % yttria-stabilized zirconia (Y2O3)3(ZrO2)97. 
     
     
         3 . The threaded ceramic implant of  claim 2  wherein said powdered zirconia has an average particle size of between 0.05 and 0.25 μm and a BET surface area of between about 8.0 and 40.0 m2/g. 
     
     
         4 . The threaded ceramic implant of  claim 1  wherein said mold cavity comprises a finely detailed surface features comprising one or more dimples, tie rods or surface texturing. 
     
     
         5 . The threaded ceramic implant of  claim 1  wherein said manufacturing process further comprises post-sintering hot isostatic pressing at a pressure of between 150 MPa and 250 MPa and at a temperature of between 1200° C. and 1350° C. 
     
     
         6 . The threaded ceramic implant of  claim 1  wherein said powdered zirconia is mixed with a water-soluble binder system with a solids loading of about 48%. 
     
     
         7 . A densely-sintered ceramic implant produced by a manufacturing process comprising:
 compacting a powdered ceramic material into a die cavity to form a powder compact having an exterior geometry and exterior surface features according to the interior geometry and interior surface features of said die cavity, said powder compact having a density greater than about 40% of maximum theoretical density;   rapidly sintering said powder compact at least in part by causing an electrical current to flow through said powder compact while simultaneously applying pressure in excess of 100 MPa; and   regulating said current and said pressure so as to maintain sufficient temperature and pressure to densely sinter said powder compact to a density greater than about 95% of theoretical density.   
     
     
         8 . The ceramic implant of  claim 7  wherein said die cavity comprises a first portion having an interior geometry and interior surface features corresponding to said ceramic implant desired to be formed and a second portion comprising a compactable shaft portion configured to be compacted via a plunger and wherein at least a portion of said powder in said compactable shaft portion flows into said first portion of said die during said rapid sintering. 
     
     
         9 . The ceramic implant of  claim 7  wherein said powdered ceramic material comprises powdered 3-mol % yttria-stabilized zirconia (Y2O3)3(ZrO2)97. 
     
     
         10 . The ceramic implant of  claim 9  wherein said powdered zirconia has an average particle size of 50 nm and a BET surface area greater than about 15 m2/g. 
     
     
         11 . The ceramic implant of  claim 9  wherein said powdered ceramic material is pressed into a graphite die by uniaxial pressing followed by cold isostatic pressing until said powder compact is formed having a density equal to or exceeding 43% of theoretical density. 
     
     
         12 . The ceramic implant of  claim 7  wherein a pulsed DC current is introduced through a pair of graphite plungers and is caused to pass directly through said powder compact, heating it at a rate exceeding 500° C./min until a maximum sintering temperature of 1050° C. is reached. 
     
     
         13 . The ceramic implant of  claim 7  wherein a pulsed DC current is introduced through a pair of graphite plungers and is caused to pass directly through said powder compact while a pressure in excess of 400 MPa is simultaneously applied via said graphite plungers so as to densely sinter said powder compact to a density greater than about 96.5% of theoretical density. 
     
     
         14 . The ceramic implant of  claim 7  wherein said implant is sufficiently densely sintered such that at least a portion of said implant is at least 25% translucent at a wavelength of 525 nm. 
     
     
         15 . A surface-modified ceramic implant produced by a manufacturing process comprising:
 injecting a powdered ceramic feedstock into a mold cavity to form a green body, said powdered ceramic feedstock comprising a colloidal mixture of powdered ceramic material suspended in a liquid binder system;   removing said green body from said mold and debinding said green body so as to remove a majority of said binder, so as to produce a debound green body having a fluid-permeable interconnected porous structure;   modifying at least a portion of the outer surface of said debound green body by introducing nanoparticles of material sufficiently small in size such that at least some of said nanoparticles enter and remain lodged in said fluid-permeable interconnected porous structure; and   sintering said nanoparticle-infused debound green body so as to form a ceramic implant having a modified outer surface.   
     
     
         16 . The ceramic implant of  claim 15  wherein said nanoparticles comprise particles of silver, gold, titanium, zirconia, YSZ, α-tricalcium phosphate, hydroxyapatite, carbon, carbon nanotubes having an average particle size of less than 500 nm. 
     
     
         17 . The ceramic implant of  claim 15  wherein said powdered ceramic feedstock comprises powdered 3-mol % yttria-stabilized zirconia (Y2O3)3(ZrO2)97. 
     
     
         18 . The ceramic implant of  claim 17  wherein said powdered zirconia has an average particle size of between 0.05 and 0.25 μm and a BET surface area of between about 8.0 and 40.0 m2/g. 
     
     
         19 . The ceramic implant of  claim 15  wherein at least a second portion of said outer surface of said implant is further modified by a PMEDC process to create a fused titanium oxide layer thereon. 
     
     
         20 . The ceramic implant of  claim 19  wherein said second portion of said outer surface of said implant is coated with an initial coating of titanium nitride (TiN) prior to initiating said PMEDC process. 
     
     
         21 .- 49 . (canceled)