Bone implant having circumferentially oriented roughness

• US 6,547,564 B1
• Filed: 10/13/1999
• Issued: 04/15/2003
• Est. Priority Date: 07/17/1998
• Status: Expired due to Term

• Current Assignee: Astra Tech AB
• Original Assignee: Astra AB (Astrazeneca PLC)
• Inventors: Hansson, Stig
• Primary Examiner(s): McDermott, Corrine
• Assistant Examiner(s): Chattopadhyay, Urmi
• Application Number:
  US09/402,918
• Time in Patent Office: 1,280 Days
• Field of Search: 433/174, 433/225, 433/172, 433/173, 433/175, 606/73, 606/61, 606/65, 606/72, 623/16.11, 623/11.11, 623/23.5
• US Class Current: 433/174
• CPC Class Codes: A61B 17/863 with thread interrupted or changing its form along shank, other than constant taper
• CPC Class Codes: A61C 8/0022 Self-screwing A61C8/0028 takes precedence
• CPC Class Codes: A61C 8/0025 with multiple threads

Abstract

Implant (10) having a shaft which is adapted in use to be embedded in bone tissue and which has an outer surface provided with a circumferentially-oriented roughness. The circumferentially-oriented roughness has first and second axial sections (19, 21) with each section comprising a series of circumferentially-oriented peaks which have a crest and which are axially spaced apart by troughs. The axial spacing (d) between the crests of adjacent peaks in the first axial section (19) is less than the axial spacing (3d) between the crests of adjacent peaks in the second axial section (21). Although the axial spacing between the crests of adjacent peaks in the first and second axial sections of circumferentially-oriented roughness differs, the first and second axial sections of circumferentially-oriented roughness are adapted in use to provide the same or substantially the same pitch.

Claims

1. A dental implant comprising a shaft having a coronal end, an apical end, and an outer surface provided with a circumferentially-oriented roughness having a first axial section and a second axial section,

wherein the implant is sized and configured to be implanted in a maxilla or mandible of a human patient,

wherein the first axial section is located coronally of the second axial section and the sections of circumferentially-oriented roughness have the same or substantially the same pitch,

wherein each of the sections comprises a series of circumferentially-oriented peaks, each peak having a crest and being axially spaced apart from adjacent peaks by troughs,

wherein the axial spacing between the crests of adjacent peaks in the first axial section is less than the axial spacing between the crests of adjacent peaks in the second axial section,

wherein the crests of all of the peaks or substantially all of the peaks in the first and second axial sections lie on an axial plane parallel to the main axis of the shaft and

wherein a bore comprising an internally-threaded section extends apically into the shaft from the coronal end.

2. The implant according to claim 1, wherein the first and second axial sections are contiguous.

3. The implant according to claim 2, wherein the first axial section extends from the coronal end of the shaft to a position coronally of the apical end and the second axial section extends from the first axial section towards the apical end.

4. The implant according to any one of claims 1, 2 and 3 wherein the bore extends to an end surface in-between the apical and coronal ends of the shaft, wherein the structure of the end-surface is sized and configured to be secured to a superstructure, wherein the internally-threaded section has a coronal edge and an apical edge for screw connection of the superstructure to the implant, and wherein the apical edge of the internally-threaded section of the bore terminates at a position which is disposed apically of the first axial section.

5. The implant according to claim 4 wherein the internally-threaded section is an apical section of the blind-bore.

6. The implant according to claim 1, wherein the pitch is a predetermined distance and the ratio of the predetermined distance to the axial spacing between the crests of adjacent peaks in the first axial section is a first multiple integer, the ratio of the predetermined distance to the axial spacing between the crests of adjacent peaks in the second axial section is a second multiple integer and the first multiple integer is greater than the second multiple integer.

7. The implant according to claim 1 or 6, wherein the height of the peaks, as measured from the troughs to the crests, in the first axial section differs from that in the second axial section.

8. The implant according to claim 7, wherein the height of the peaks in the first axial section is less than the height of the peaks in the second axial section.

9. The implant according to claim 1 or 6, wherein the height of the peaks, as measured from the troughs to the crests, in the first axial section is the same or substantially the same as in the second axial section.

10. The implant according to claim 1 or 6, wherein the ratio of the height of the peaks, as measured from the troughs to the crests, to the axial spacing between the crests of adjacent peaks in the first axial section is the same or substantially the same as in the second axial section.

11. The implant according to claim 1 or 6, wherein the height of the peaks, as measured from the troughs to the crests, in the first axial section is no greater than 0.20 mm.

12. The implant according to claim 1 or 6, wherein the height of the peaks, as measured from the troughs to the crests, in the second axial section is in the range 0.15-1 mm.

13. The implant according to claim 1 or 6, wherein the circumferentially-oriented roughness in at least one of the first and second axial sections is presented by a screw thread profile with the circumferentially-oriented peaks being defined by thread elements of the screw thread profile.

14. The implant according to claim 13, wherein the screw thread profile is formed by a screw thread structure.

15. The implant according to claim 13 wherein both the first and second axial sections are presented by a screw thread profile with the circumferentially-oriented peaks being defined by thread elements of the screw thread profiles.

16. The implant according to claim 15, wherein the screw thread profile of the first axial section is formed by a first set of at least two independent screw threads each screw thread forming turns, the turns of each independent screw thread in the first set defining thread elements in the first axial section and being alternately arranged with the screw thread elements of the other independent screw threads in the first set, wherein adjacent screw thread elements of any of the independent screw threads of the first set are axially spaced apart from each other by a predetermined spacing distance, wherein the spacing distance is the same for the adjacent screw thread elements of the other independent screw threads in the first set, and wherein,

the screw thread profile of the second axial section is formed by (i) a single screw thread having turns which define the thread elements of the second axial section and are axially spaced apart from each other by the predetermined spacing distance or approximately the predetermined spacing distance, or (ii) a second set of independent screw threads numbering less than in the first set, each screw thread having turns, the turns of each independent screw thread in the second set defining screw thread elements in the second axial section, the screw thread elements of one independent screw thread of the second set being alternately arranged with the screw thread elements of the other independent screw threads in the second set with adjacent screw thread elements of each independent screw thread of the second set being axially spaced apart from each other by the predetermined spacing distance or approximately the predetermined spacing distance.

17. The implant according to claim 16, wherein at least one of the independent screw threads of the first and second axial sections is shared by the first and second axial sections.

18. The implant according to claim 16, wherein the or each independent screw thread of at least one of the first and second axial sections is a microthread.

19. The implant according to claim 18, wherein only the independent screw threads of the first axial section are microthreads.

20. The implant according to claim 18, wherein the independent screw threads of the first and second axial sections are microthreads.

21. The implant according to claim 1 or 6, wherein the circumferentially-oriented roughness in at least one of the first and second axial sections is formed by a series of axially spaced apart circumferential lines of beads.

22. The implant according to claim 21, wherein the beads in each line are circumferentially spaced apart.

23. The implant according to claim 1, wherein the height (h1, h2) of the peaks, as measured from the troughs to the crests, in the first axial section differs from that in the second axial section.

24. The implant according to claim 1, wherein the height (h1, h2) of the peaks, as measured from the troughs to the crests, in the first axial section is the same or substantially the same as in the second axial section.

25. The implant according to claim 1, wherein the ratio of the height of the peaks, as measured from the troughs to the crests, to the axial spacing between the crests of adjacent peaks in the first axial section is the same or substantially the same as in the second axial section.

26. The implant according to claim 1, wherein the circumferentially-oriented roughness consists of a first axial section and a second axial section.

82. A method of implanting an implant into a bone structure comprising the steps of:

providing an implant according to any one of claims 1, 6, 27, 40, 53, and 58;

providing a bore-hole in the bone tissue structure; and

screwing the implant into the bore-hole so that the shaft is embedded in the bone tissue.

27. An implant comprising a shaft, wherein the shaft is sized and configured to be embedded in bone tissue and comprises a coronal end having a coronal end portion with a maximum lateral dimension not exceeding the maximum lateral dimension of the shaft, an apical end, and an outer surface having at least two axial sections having circumferentially-oriented roughness, each of the sections comprising a series of circumferentially-oriented peaks, each peak having a crest and being axially spaced apart from adjacent peaks by troughs,

wherein the axial spacing between the crests of adjacent peaks of a section is less than the axial spacing between the crests of adjacent peaks of any apically-located axial section,

wherein the sections of circumferentially-oriented roughness have the same or substantially the same pitch, and

wherein the crests of all of the peaks or substantially all of the peaks in the first and second axial sections lie on an axial plane parallel to the main axis of the shaft.

28. The implant according to claim 27, wherein at least two of the axial sections are contiguous.

29. The implant according to claim 27, wherein a blind bore extends apically into the shaft from the coronal end to an end surface in-between the apical and coronal ends of the shaft, wherein the structure of the end-surface is capable of being secured to a superstructure, wherein the blind bore comprises an internally-threaded section having a coronal edge and an apical edge for screw connection of the superstructure to the implant, and wherein the apical edge of the internally-threaded section of the blind bore terminates at a position which is disposed apically of the first axial section of the at least two axial sections.

30. The implant according to claim 27, wherein for at least one pair of the axial sections, a first axial section being located coronally of a second axial section, the pitch is a predetermined distance, that the ratio of the predetermined distance to the axial spacing between the crests of adjacent peaks in the first axial section is a first multiple integer, that the ratio of the predetermined distance to the axial spacing between the crests of adjacent peaks in the second axial section is a second multiple integer and that the first multiple integer is greater than the second multiple integer.

31. The implant according to claim 30, the height of the peaks, as measured from the troughs to the crests, in the first axial section differs from that in the second axial section.

32. The implant according to claim 31, wherein the height of the peaks in the first axial section is less than the height of the peaks in the second axial section.

33. The implant according to claim 30, wherein the height of the peaks, as measured from the troughs to the crests, in the first axial section is the same or substantially the same as in the second axial section.

34. The implant according to claim 30, wherein the ratio of the height of the peaks, as measured from the troughs to the crests, to the axial spacing between the crests of adjacent peaks in the first axial section is the same or substantially the same as in the second axial section.

35. The implant according to claim 30, wherein the height of the peaks, as measured from the troughs to the crests, in the first axial section is no greater than 0.20 mm.

36. The implant according to claim 30, wherein the height of the peaks, as measured from the troughs to the crests, in the second axial section is in the range 0.15-1 mm.

37. The implant according to claim 30, wherein the circumferentially-oriented roughness in at least one of the first and second axial sections is presented by a screw thread profile with the circumferentially-oriented peaks being defined by thread elements of the screw thread profile.

38. The implant according to claim 37, wherein both the first and second axial sections are presented by a screw thread profile wherein the circumferentially-oriented peaks are defined by screw thread elements of the screw thread profiles, wherein the screw thread profile of the first axial section is formed by a first set of at least two independent screw threads, each screw thread having turns, the turns of each independent screw thread in the first set defining thread elements in the first axial section and being alternately arranged with the screw thread elements of the other independent screw threads in the first set, wherein adjacent screw thread elements of each one of the independent screw threads of the first set are axially spaced apart from each other by a predetermined spacing distance, wherein the spacing distance is the same for the adjacent screw thread elements of the other independent screw threads in the first set, and wherein,

the screw thread profile of the second axial section is formed by (i) a single screw thread having turns which define the screw thread elements of the second axial section and are axially spaced apart from each other by the predetermined spacing distance or approximately the predetermined spacing distance, or (ii) a second set of independent screw threads numbering less than in the first set, each having turns, the turns of each independent screw thread in the second set defining screw thread elements in the second axial section, the screw thread elements of one independent screw thread of the second set being alternately arranged with the screw thread elements of the other independent screw threads of the second set with adjacent screw thread elements of each independent screw thread of the second set being axially spaced apart from each other by the predetermined spacing distance or approximately the predetermined spacing distance.

39. The implant according to claim 27, wherein the implant is sized and configured to be implanted in a maxilla or a mandible of an edentulous patient for supporting a superstructure which presents one or more artificial teeth.

40. An implant comprising a shaft, wherein the shaft is sized and configured to be embedded in bone tissue and comprises a coronal end having a coronal end portion with a maximum lateral dimension not exceeding the maximum lateral dimension of the shaft an apical end, and an outer surface provided with a circumferentially-oriented roughness consisting of a first axial section and a second axial section, each of the sections comprising a series of circumferentially-oriented peaks, each peak having a crest and being axially spaced apart from adjacent peaks by troughs,

wherein the axial spacing between the crests of adjacent peaks in the first axial section is less than the axial spacing between the crests of adjacent peaks in the second axial section,

wherein the first and second axial sections of circumferentially-oriented roughness have the same or substantially the same pitch,

wherein the first axial section is located coronally of the second axial section, and

wherein the crests of all of the peaks or substantially all of the peaks in the first and second axial sections lie on an axial plane parallel to the main axis of the shaft.

41. The implant according to claim 40, wherein the first and second axial sections are contiguous.

42. The implant according to claim 40, wherein a blind bore extends apically into the shaft from the coronal end to an end surface in-between the apical and coronal ends of the shaft, wherein the structure of the end-surface is capable of being secured to a superstructure, wherein the blind bore comprises an internally-threaded section having a coronal edge and an apical edge for screw connection of the superstructure to the implant, and wherein the apical edge of the internally-threaded section of the blind bore terminates at a position which is disposed apically of the first axial section.

43. The implant according to claim 40, wherein the pitch is a predetermined distance, that the ratio of the predetermined distance to the axial spacing between the crests of adjacent peaks in the first axial section is a first multiple integer, that the ratio of the predetermined distance to the axial spacing between the crests of adjacent peaks in the second axial section is a second multiple integer and that the first multiple integer is greater than the second multiple integer.

44. The implant according to claim 40 or 43, wherein the height of the peaks, as measured from the troughs to the crests, in the first axial section differs from that in the second axial section.

45. The implant according to claim 44, wherein the height of the peaks in the first axial section is less than the height of the peaks in the second axial section.

46. The implant according to claim 40 or 43, wherein the height of the peaks, as measured from the troughs to the crests, in the first axial section is the same or substantially the same as in the second axial section.

47. The implant according to claim 40 or 43, wherein the ratio of the height of the peaks, as measured from the troughs to the crests, to the axial spacing between the crests of adjacent peaks in the first axial section is the same or substantially the same as in the second axial section.

48. The implant according to claim 40 or 43, wherein the height of the peaks, as measured from the troughs to the crests, in the first axial section is no greater than 0.20 mm.

49. The implant according to claim 40 or 43, wherein the height of the peaks, as measured from the troughs to the crests, in the second axial section is in the range 0.15-1 mm.

50. The implant according to claim 40 or 43, wherein the circumferentially-oriented roughness in at least one of the first and second axial sections is presented by a screw thread profile with the circumferentially-oriented peaks being defined by thread elements of the screw thread profile.

51. The implant according to claim 50, wherein both the first and second axial sections are presented by a screw thread profile wherein the circumferentially-oriented peaks are defined by screw thread elements of the screw thread profiles, wherein the screw thread profile of the first axial section is formed by a first set of at least two independent screw threads each screw thread forming turns, the turns of each independent screw thread in the first set defining screw thread elements in the first axial section and being alternately arranged with the screw thread elements of the other independent screw threads in the first set, wherein adjacent screw thread elements of each of the independent screw threads of the first set are axially spaced apart from each other by a predetermined spacing distance, wherein the spacing distance is the same for the adjacent screw thread elements of the other independent screw threads in the first set, and wherein,

the screw thread profile of the second axial section is formed by (i) a single screw thread having turns which define the thread elements of the second axial section and are axially spaced apart from each other by the predetermined spacing distance or approximately the predetermined spacing distance, or (ii) a second set of independent screw threads numbering less than in the first set, each screw thread forming turns, the turns of each independent screw thread in the second set defining screw thread elements in the second axial section and being alternately arranged with the screw thread elements of the other independent screw threads in the second set, with adjacent screw thread elements of each independent screw thread of the second set being axially spaced apart from each other by the predetermined spacing distance or approximately the predetermined spacing distance.

52. The implant according to claim 40, the implant is sized and configured to be implanted in a maxilla or a mandible of an edentulous patient for supporting a superstructure which presents one or more artificial teeth.

53. An implant comprising a shaft sized and configured to be embedded in a maxilla or mandible, wherein the shaft comprises a coronal end, an apical end, and an outer surface having a plurality of axial sections having circumferentially-oriented roughness and the sections of circumferentially-oriented roughness have the same or substantially the same pitch, each of the sections comprising a series of circumferentially-oriented peaks, each peak having a crest and being axially spaced apart from adjacent peaks by troughs,

wherein the axial spacing between the crests of adjacent peaks of a section is less than the axial spacing between the crests of adjacent peaks of the adjacent apically-located axial section,

wherein the crests of all of the peaks or substantially all of the peaks in at least two of said sections lie on an axial plane parallel to the main axis of the shaft, and

wherein a bore comprising an internally-threaded section extends apically into the shaft from the coronal end.

54. The implant according to claim 53, wherein the crests of all of the peaks, or substantially all of the peaks, in all of said axial sections lie on an axial plane parallel to the main axis of the shaft.

55. The implant according to claim 54, wherein the height (h1, h2) of the peaks, as measured from the troughs to the crests, in the first axial section differs from that in the second axial section.

56. The implant according to claim 54, wherein the height (h1, h2) of the peaks, as measured from the troughs to the crests, in the first axial section is the same or substantially the same as in the second axial section.

57. The implant according to claim 54, wherein the ratio of the height of the peaks, as measured from the troughs to the crests, to the axial spacing between the crests of adjacent peaks in the first axial section is the same or substantially the same as in the second axial section.

58. A dental implant comprising a shaft having a coronal end, an apical end, and an outer surface provided with a circumferentially-oriented roughness having a first axial section and a second axial section,

wherein the implant is sized and configured to be implanted in a maxilla or mandible of a human patient,

wherein the first axial section is located coronally of the second axial section and the sections of circumferentially-oriented roughness have the same or substantially the same pitch,

wherein each of the sections comprises a series of circumferentially-oriented peaks, each peak having a crest and being axially spaced apart from adjacent peaks by troughs, and wherein the axial spacing between the crests of adjacent peaks in the first axial section is less than the axial spacing between the crests of adjacent peaks in the second axial section,

wherein the crests of all of the peaks or substantially all of the peaks in the first and second axial sections lie in an axial plane parallel to the main axis of the shaft, and

wherein a bore extends apically into the shaft from the coronal end and terminates at a position disposed apically from the first axial section.

59. The implant according to claim 58, wherein the first and second axial sections are contiguous.

60. The implant according to claim 59, wherein the first axial section extends from the coronal end of the shaft to a position coronally of the apical end and the second axial section extends from the first axial section towards the apical end.

61. The implant according to any one of claim 58-60, wherein the bore extends to an end surface in-between the apical and coronal ends of the shaft, wherein the structure of the end-surface is capable of being secured to a superstructure, wherein the bore comprises an internally-threaded section having a coronal edge and an apical edge for screw connection of the superstructure to the implant, and wherein the apical edge of the internally-threaded section of the bore terminates at a position which is disposed apically of the first axial section.

62. The implant according to claim 61, wherein the internally-threaded section is an apical section of the bore.

64. The implant according to claim 58-63, wherein the height of the peaks, as measured from the troughs to the crests, in the first axial section differs from that in the second axial section.

65. The implant according to claim 64, wherein the height of the peaks in the first axial section is less than the height of the peaks in the second axial section.

66. The implant according to claim 58 or 63 the height of the peaks, as measured from the troughs to the crests, in the first axial section is the same or substantially the same as in the second axial section.

67. The implant according to claim 58 or 63, wherein the ratio of the height.of the peaks, as measured from the troughs to the crests, to the axial spacing between the crests of adjacent peaks in the first axial section is the same or substantially the same as in the second axial section.

68. The implant according to claim 58 or 63, wherein the height of the peaks, as measured from the troughs to the crests, in the first axial section is no greater than 0.20 mm.

69. The implant according to claim 58 or 63, wherein the height of the peaks, as measured from the troughs to the crests, in the second axial section is in the range 0.15-1 mm.

70. The implant according to claim 58 or 63, wherein the circumferentially-oriented roughness in at least one of the first and second axial sections is presented by a screw thread profile with the circumferentially-oriented peaks being defined by thread elements of the screw thread profile.

71. The implant according to claim 70 wherein both the first and second axial sections are presented by a screw thread profile with the circumferentially-oriented peaks being defined by thread elements of the screw thread profiles.

72. The implant according to claim 70, wherein the or each screw thread profile is formed by a screw thread structure.

73. The implant according to claim 71, wherein the or each screw thread profile is formed by a screw thread structure.

74. The implant according to claim 73, wherein the screw thread profile of the first axial section is formed by a first set of independent screw threads each screw thread having turns, the turns of each independent screw thread in the first set defining thread elements in the first axial section and being sequentially arranged with the turns of the other independent screw threads in the first set with adjacent turns of one of the independent screw threads of the first set being axially spaced apart by a predetermined spacing distance which is the same for adjacent turns of the other independent screw threads in the first set, and wherein the screw thread structure of the second axial section is formed by (i) an independent screw thread having turns which define the thread elements of the second axial section and are axially spaced apart by the predetermined spacing distance or essentially the predetermined spacing distance, or (ii) a second set of independent screw threads numbering less than in the first set each having turns, the turns of each independent screw thread in the second set defining thread elements in the second axial section and being sequentially arranged with the turns of the other independent screw threads in the second set with adjacent turns of each independent screw thread of the second set being axially spaced apart by the predetermined spacing distance or a distance approximating the predetermined spacing distance.

75. The implant according to claim 74, wherein at least one of the independent screw threads of the first and second axial sections is shared by the first and second axial sections.

76. The implant according to claim 74, wherein the or each independent screw thread of at least one of the first and second axial sections is a microthread.

77. The implant according to claim 76, wherein only the independent screw threads of the first axial section are microthreads.

78. The implant according to claim 76, wherein the independent screw threads of the first and second axial sections are microthreads.

79. The implant according to claim 58 or 63, wherein the circumferentially-oriented roughness in at least one of the first and second axial sections is formed by a series of axially spaced apart circumferential lines of beads.

80. The implant according to claim 79, wherein the beads in each line are circumferentially spaced apart.

81. The implant according to claim 58, wherein the circumferentially-oriented roughness consists of a first axial section and a second axial section.

63. The implant according to claim 94, wherein the pitch is a predetermined distance and the ratio of the predetermined distance to the axial spacing between the crests of adjacent peaks in the first axial section is a first multiple integer, the ratio of the predetermined distance to the axial spacing between the crests of adjacent peaks in the second axial section is a second multiple integer and the first multiple integer is greater than the second multiple integer.