Ceramic endosseous implant

• US 4,259,072 A
• Filed: 07/25/1979
• Issued: 03/31/1981
• Est. Priority Date: 04/04/1977
• Status: Expired due to Term

• Current Assignee: Kyoto Ceramic Company Limited
• Original Assignee: Kyoto Ceramic Company Limited
• Inventors: Kawahara, Haruyuki, Hirabayashi, Masaya
• Primary Examiner(s): Serwin, R. E.
• Application Number:
  US06/060,649
• Time in Patent Office: 615 Days
• Field of Search: 3/1, 3/1.91, 3/1.911, 3/1.912, 3/1.913, 3/1.9, 32/10 A, 32/10 R, 128/92 R, 128/92 C, 128/92 CA, 433/173, 433/201
• US Class Current: 433/173
• 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 8/0018 characterised by the shape
• CPC Class Codes: A61C 8/005 Connecting devices for joining an upper structure with an implant member, e.g. spacers
• CPC Class Codes: A61C 8/0054 having a cylindrical implant connecting part
• CPC Class Codes: A61C 8/0059 with additional friction enhancing means
• CPC Class Codes: A61F 2/30907 Nets or sleeves applied to surface of prostheses or in cement
• CPC Class Codes: A61F 2/36 Femoral heads ; Femoral endoprostheses
• CPC Class Codes: A61F 2/3662 Femoral shafts
• 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 2002/30084 Materials having a crystalline structure
• CPC Class Codes: A61F 2002/30968 Sintering
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2250/0024 made from both porous and non-porous parts, e.g. adjacent parts
• CPC Class Codes: A61F 2310/00179 Ceramics or ceramic-like structures
• CPC Class Codes: A61F 2310/00293 containing a phosphorus-containing compound, e.g. apatite
• 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: A61L 2430/02 for reconstruction of bones; weight-bearing implants
• CPC Class Codes: A61L 27/12 Phosphorus-containing materials, e.g. apatite
• CPC Class Codes: A61L 27/32 Phosphorus-containing materials, e.g. apatite

Abstract

This disclosure relates to an endosseous implant for use in dental and orthopedic treatment. The implant is a composite structure made of a combination of an outer ceramic member and an inner ceramic core member bonded together by glass cement. After being implanted, new bone tissue and new connective tissue penetrate into the outer member to form a net-like root structure therein, thereby increasing the stability of the implant and at the same time the outer member is reinforced by the inner core member.

Claims

1. A ceramic endosseous implant, comprising:

a composite structural member having a ceramic outer member of polycrystalline alumina ceramic and a ceramic inner core member of single crystalline alumina ceramic;

said outer member having a generally cylindrical shape and a cavity with micro-apertures on the outer surface thereof for permitting the penetration of a new bone and connective tissue thereinto;

said inner member, of alumina ceramic, with a post portion adapted to be inserted in said cavity, a flange portion adjacent said post portion for the covering of said cavity, and a mounting post for use in attaching a prothesis; and

said inner core member bonded to said outer member by a heat resistant glass cement having a coefficient of thermal expansion approximating that of alumina ceramic.

2. An implant according to claim 1 wherein said inner core member is made of a single crystalline ceramic.

3. An implant according to claim 1 wherein said cement has a coefficient of thermal expansion approximating that of said inner core member and said outer member.

4. An implant according to claim 1 wherein said cement has the following composition by weight:

space="preserve" listing-type="tabular">______________________________________ SiO.sub.2 57% (by weight) B.sub.2 O.sub.3 23% Al.sub.2 O.sub.3 2% Na.sub.2 O.sub.3 3% BaO 7% ZnO 8% Total 100% ______________________________________

5. An implant according to claim 1 wherein said outer member comprises protuberances on its outer surface to aid in securely engaging surrounding tissue.

6. An implant according to claim 5 wherein said protrusion on said ceramic outer member is an external thread adapted to be threadedly fitted into said tissue.

7. An implant according to claim 5 wherein said protrusions on said ceramic outer member are formed by discontinuous ringlike or helical recesses adapted to engage said tissue.

8. A ceramic endosseous implant according to claim 1 wherein said micro-apertures have a diameter greater than 20 μ

m.

9. A ceramic endosseous implant according to claim 1 wherein said micro-apertures have a diameter of 20-700 μ

m.

10. A ceramic endosseous implant according to claim 1 wherein said micro-apertures have a diameter of 500 μ

m-5 mm.

11. A ceramic endosseous implant according to claim 1 wherein said outer member and said inner member are sintered together.

12. A ceramic endosseous implant according to claim 1 wherein said outer member and said inner member are threaded together.

13. An implant according to claim 1 wherein said cement is a heat-resistant Al₂ O₃ -based cement.

14. A ceramic endosseous implant, comprising:

a composite structural member having a ceramic outer member of polycrystalline alumina ceramic and a ceramic inner core member of single crystalline alumina ceramic;

said outer member, having a generally cylindrical shape and a cavity, manufactured to have material distributed therethrough in a predetermined configuration, said material being degradeable by new bone and connective tissue when said implant is inserted into a living being, forming micro-apertures in said outer member into which said new bone and connective tissue may penetrate;

said inner member of alumina ceramic, configured to reinforce said outer member, with a post portion adapted to be inserted in said cavity, a flange portion adjacent said post portion for the covering of said cavity, and a mounting post for use in attaching a prothesis;

said inner core member bonded to said outer member by a heat resistant glass cement having a coefficient of thermal expansion approximating that of alumina ceramic.

16. A ceramic endosseous implant according to claim 14 wherein said outer member and said inner core member are threaded together.

17. An implant according to claim 14 wherein said material comprises apatite.

15. A ceramic endosseous implant comprising a composite structural member having a ceramic outer member of polycrystalline alumina ceramic and a ceramic inner core member fused together by a glass cement having a coefficient of thermal expansion approximating that of alumina ceramic, said outer member having micro-apertures on the outer surface thereof for permitting the penetration of new bone and connective tissue thereinto, and said inner member made of single crystalline alumina ceramic and configured to reinforce said outer member.

18. A ceramic outer member, having a cavity, for permanent insertion into body tissues, having an outer surface contacting said tissues and formed to encourage the growth of said tissues into said member, and further having a shape to mechanically engage said tissues during said growth;

a single crystalline ceramic inner core member shaped to fill said cavity and to provide an protrusion for attaching a prothesis;

said inner core member permanently affixed to said outer member by a glass cement having coefficient of thermal expansion approximating that of said outer and inner core members.

19. An implant according to claim 18 wherein the outer surface of said outer member contains micro-apertures of size to encourage the growth of said tissues into said apertures.

20. An implant according to claim 19 wherein the size of said micro-apertures are selectively apportioned in accordance with a desired ratio of growth into said apertures of bone and connective tissues to provide an affixation of said member having predetermined proportion of strength and elasticity.

21. An implant according to claim 18 wherein said outer member'"'"'s outer surface comprises a material able to be degraded and replaced by tissue in contact with said material.

22. An implant according to claim 21 wherein said material comprises apatite.

23. An implant according to claim 18 wherein said cement has penetrated the surfaces of said inner core and outer member in contact with each other and fused said members together.