U.S. patent application number 10/154875 was filed with the patent office on 2002-10-03 for single-stage implant system.
Invention is credited to Brown, Gale R., Goodman, Ralph E., Lazzara, Richard J., Rogers, Dan Paul.
Application Number | 20020142266 10/154875 |
Document ID | / |
Family ID | 27369913 |
Filed Date | 2002-10-03 |
United States Patent
Application |
20020142266 |
Kind Code |
A1 |
Rogers, Dan Paul ; et
al. |
October 3, 2002 |
Single-stage implant system
Abstract
A single stage dental implant for implantation in living jawbone
having overlying gingiva comprises a generally cylindrical body
section having an exterior surface for confronting the jawbone and
a head section attached to the body section for extending through
the overlying gingiva when the body section is confronting the
jawbone. The head section has an end portion which is generally
near an outer layer of the gingiva. The implant further includes a
bore within the head section extending to an opening at the end
portion of the head section. The bore is defined by first, second,
and third walls. The first wall has internal threads. The second
wall has a larger diameter than the first surface and is
substantially cylindrical. The second wall extends from the first
wall toward the end portion. The third wall extends from the second
wall to the opening and flares toward the opening to a diameter
that is wider than a diameter of the second wall. The implant is
delivered to the site in the patient's mouth with a carrier that is
expanded into the second wall of the bore thereby developing a
tight engagement capable of withstanding the insertion torque. The
implant can be fitted with posts which extend above the upper
portion of the implant. The post can be fitted with gingival
forming components and temporary posts.
Inventors: |
Rogers, Dan Paul; (Royal
Palm Beach, FL) ; Brown, Gale R.; (Palm City, FL)
; Goodman, Ralph E.; (West Palm Beach, FL) ;
Lazzara, Richard J.; (Lake Worth, FL) |
Correspondence
Address: |
JENKENS & GILCHRIST, P.C.
225 WEST WASHINGTON
SUITE 2600
CHICAGO
IL
60606
US
|
Family ID: |
27369913 |
Appl. No.: |
10/154875 |
Filed: |
May 24, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10154875 |
May 24, 2002 |
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09731589 |
Dec 7, 2000 |
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6394809 |
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09731589 |
Dec 7, 2000 |
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09164934 |
Oct 1, 1998 |
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6217331 |
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60074404 |
Feb 11, 1998 |
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60060801 |
Oct 3, 1997 |
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60061076 |
Oct 3, 1997 |
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Current U.S.
Class: |
433/173 ;
433/174 |
Current CPC
Class: |
A61C 8/0059 20130101;
A61C 8/0001 20130101; A61C 13/0001 20130101; A61C 8/006 20130101;
A61C 8/0065 20130101; A61C 8/0037 20130101; A61C 8/008 20130101;
A61C 8/0089 20130101; A61C 8/0033 20130101; A61C 8/0066 20130101;
A61C 8/0071 20130101; A61C 8/0054 20130101; A61C 8/005 20130101;
A61C 8/0048 20130101; A61C 8/0069 20130101; A61C 8/0057
20130101 |
Class at
Publication: |
433/173 ;
433/174 |
International
Class: |
A61C 008/00 |
Claims
1. A dental implant for implantation in living jawbone having
overlying gingiva, comprising: a generally cylindrical body section
having an exterior surface for confronting said jawbone; a head
section attached to said body section for extending through said
overlying gingiva when said body section is confronting said
jawbone, said head section having an end portion which is generally
near an outer layer of said gingiva; and a bore within said head
section extending to an opening at said end portion of said head
section, said bore being defined by first, second, and third walls,
said first wall having internal threads, said second wall having a
larger diameter than said first surface and being substantially
cylindrical, said second wall extending from said first wall toward
said end portion, said third wall extending from said second wall
to said opening, said third wall flaring toward said opening to a
diameter that is wider than a diameter of said second wall.
2. The dental implant of claim 1, wherein said second wall is
fitted with at least one thread groove separated by lands on said
second wall such that said bore has two distinct internally
threaded sections.
3. The dental implant of claim 2, wherein said lands preserve a
major portion of said second wall.
4. The dental implant of claim 2, wherein said thread grooves form
a multi-lead thread.
5. The dental implant of claim 4, wherein a pitch of said thread
grooves is approximately one millimeter.
6. The dental implant of claim 1, wherein said head section flares
outwardly from said main body toward said end portion.
7. The dental implant of claim 6, wherein said exterior surface of
said main body section is threaded and said head section has a
smooth external surface.
8. The dental implant of claim 1, wherein said bore extends into
said body section.
9. The dental implant of claim 8, wherein said first wall is
entirely within said body section.
10. The dental implant of claim 8, wherein said third wall is
entirely within said head section.
11. The dental implant of claim 10, wherein said second wall is
entirely within said head section.
12. The dental implant of claim 1, wherein said end portion of said
head section includes a generally annular surface that is at an
angle with respect to a central axis of said implant, said angle
being substantially less that 90.degree..
13. The dental implant of claim 12, wherein said end portion
further includes a non-round fitting adjacent to said annular
surface.
14. The dental implant of claim 12, wherein said angle is
approximately 45.degree.
15. The dental implant of claim 1, wherein said exterior surface of
said main body section is roughened and said head section has a
smooth external surface.
16. The dental implant of claim 1, wherein said flaring of said
third wall is at angle suitable to provide a locking taper for
engagement with a corresponding taper on a mating component.
17. A system for delivering an implant into living bone comprising:
an implant having an exterior surface for confronting said living
bone and including a bore that has an opening at an end portion of
said implant, said bore being at least partially defined by a
substantially cylindrical section; a carrier device having an
expandable portion and a non-round fitting, said expandable portion
being inserted to said substantially cylindrical section of said
bore of said implant, said non-round fitting being accessible near
said end portion of said implant; and means for expanding said
expandable cylindrical segment into tight engagement with said
substantially cylindrical section of said bore.
18. The implant delivery system of claim 17, wherein said bore
further includes a threaded section positioned below said
cylindrical segment.
19. The implant delivery system of claim 18, wherein said bore
further includes a flared section positioned above said cylindrical
section.
20. The implant delivery system of claim 17, wherein said
substantially cylindrical section has an uninterrupted circular
cross-section.
21. The implant delivery system of claim 17, wherein said
expandable portion includes a plurality of fingers having radial
extremities which reside on a generally circular locus.
22. The implant delivery system of claim 21, wherein a diameter of
said generally circular locus is slightly less than a diameter of
said substantially cylindrical section prior to the actuation of
said expanding means.
23. The implant delivery system of claim 17, wherein said carrier
has a hollow section within said expandable portion, said expanding
means includes a structure inserted into said hollow section.
24. The implant delivery system of claim 23, wherein said hollow
section includes internal threads and said structure has outer
threads for threadably engaging said internal threads of said
hollow structure.
25. The implant delivery system of claim 24, wherein said hollow
section includes wedge blocks for engaging an end of said
structure.
26. The implant delivery system of claim 17, wherein said carrier
includes a radially extending flange between said non-round fitting
and said expandable portion for engaging said end portion of said
implant.
27. The implant delivery system of claim 26, wherein said end
portion includes a generally annular surface that is at an angle
with respect to a central axis of said implant, said angle being
less substantially less that 90.degree., said radially extending
flange has a surface cooperating with said generally annular
surface.
28. The implant delivery system of claim 17, wherein said generally
cylindrical wall includes thread grooves separated by lands on said
generally cylindrical wall.
29. The implant delivery system of claim 28, wherein said
expandable portion has threads which mate with said thread
grooves.
30. The implant delivery system of claim 28, wherein said bore has
a second threaded section of a different diameter than said first
threaded region for engaging fasteners holding artificial dentition
on said implant.
31. A system for delivering an implant into living bone comprising:
an implant having an exterior surface for confronting said living
bone and including a bore that has an opening at an end portion of
said implant, said bore being at least partially defined by a
threaded section; a carrier device having an expandable threaded
portion and a non-round fitting, said expandable threaded portion
being threadably inserted into said threaded section of said bore
of said implant, said non-round fitting being accessible near said
end portion of said implant; and means for expanding said
expandable threaded segment into tight engagement with said
threaded section of said bore.
32. The implant delivery system of claim 31, wherein said threaded
section is formed by multi-lead threads.
33. The implant delivery system of claim 32, wherein a pitch of
said threaded section is approximately one millimeter.
34. The implant delivery system of claim 31, wherein a torque
required to threadably insert said expandable threaded portion into
said threaded section of said bore is less about 10 N-cm prior to
actuation of said expanding means.
35. The implant delivery system of claim 31, wherein said non-round
fitting is capable of receiving about 40 N-cm of torque while said
implant is held non-rotationally without significant movement of
said expandable threaded portion relative to said threaded section
due to said tight engagement of said expanding means.
36. The implant delivery system of claim 35, wherein said non-round
fitting is capable of receiving 100 N-cm of torque while said
implant is held non-rotationally without significant movement of
said expandable threaded portion relative to said threaded section
due to said tight engagement.
37. The implant delivery system of claim 31, wherein said
expandable threaded portion is fully inserted into said threaded
section in approximately one turn.
38. The implant delivery system of claim 31, wherein said carrier
has a hollow section within said expandable portion, said expanding
means includes a structure inserted into said hollow section.
39. The implant delivery system of claim 38, wherein said hollow
section includes internal threads and said structure has outer
threads for threadably engaging said internal threads of said
hollow structure.
40. A restoration system for fixing artificial dentition to
edentulous living jawbone, comprising: an implant including a body
section with an exterior surface for confronting said jawbone and a
head section attached to said body section for extending through
said overlying gingiva when said main body section is confronting
said jawbone, said head section having an end portion which is
generally near an outer layer of said gingiva, said implant further
having a bore within said head section extending to an opening at
said end portion of said head section, said bore being defined by
first, second, and third walls, said first wall having internal
threads, said second wall having a larger diameter than said first
surface and being substantially cylindrical, said second wall
extending from said first wall toward said end surface, said third
wall extending from said second wall to said opening, said third
wall flaring outwardly at an angle toward said opening; and a post
including a first externally-threaded post section for engagement
within said internally-threaded first wall of said bore, a second
post section of larger diameter than said first post section to fit
within said second wall of said bore, and a third post section for
engagement with said third wall of said bore, said third post
section flaring on substantially the same angle as said third wall
for locking engagement with said third wall.
41. The restoration system of claim 40, wherein said post further
has, adjacent to said third post section, a support section for
receiving said artificial dentition, said support section having a
transverse dimension adjacent to said third post section which is
generally the same size as a diameter of said bore at said
opening.
42. The restoration system of claim 40, wherein said support
section has a remote end positioned distally from said third post
section, said support section tapering to a smaller transverse
dimension at said remote end.
43. The restoration system of claim 40, further including a
lubricant between said third post section and said third wall.
44. The restoration system of claim 43, wherein said lubricant is
solid lubricant.
45. The restoration system of claim 44, wherein said solid
lubricant is a plating on said third post section.
46. A restoration system for fixing artificial dentition to
edentulous living jawbone, comprising: a dental implant having a
body for confronting said jawbone and a head section terminating in
an end portion accessible outside said jawbone, said implant having
a bore with an opening at said end portion, said end portion
including a generally annular surface and non-rotational engagement
means outside of said bore and adjacent to said annular surface,
said non-rotational engagement means is capable of interlocking
with complementary engagement means of said artificial dentition;
and a post for supporting said dentition, said post having a first
part extending into said bore for axially retaining said post to
said implant and a second part extending beyond said end portion of
said implant on which said artificial dentition is mounted, said
second part having a transverse dimension adjacent to said opening
that is smaller than a transverse dimension of said end portion
such that said non-rotational engagement means is exposed when said
post is fixed to said implant.
47. The restoration system of claim 46, wherein said non-rotational
engagement means is a boss of non-round cross-section.
48. The restoration system of claim 47, wherein said boss has "n"
sides and the cross-sectional shape of said complementary
engagement is adapted to provide at least "2n" fixed orientation
positions of said artificial dentition around said post.
49. The restoration system of claim 48, wherein said boss has a
hexagonal cross-sectional shape.
50. The restoration system of claim 47, wherein said boss is
directly adjacent to said annular surface.
51. The restoration system of claim 47, wherein said annular
surface is at approximately 90.degree. with respect to a central
axis of said implant.
52. A transition component for converting a dental implant lacking
a non-round fitting at its uppermost surface into a modified dental
implant having an external non-round boss, said dental implant
having bore that extends to an opening in an end portion, said bore
being defined by first, second, and third walls, said first wall
having internal threads, said second wall having a larger diameter
than said first surface and being substantially cylindrical, said
second wall extending from said first wall toward said end portion,
said third wall extending from said second wall to said opening,
said third wall flaring toward said opening to a diameter that is
wider than a diameter of said second wall, said transition
component comprising: a lower threaded segment for engaging said
internally threaded first wall; a tapering segment for engaging
said third wall, said tapering segment tightly engaging said third
wall in response to said lower threaded segment being fully
threaded into said first wall; and a protruding non-round fitting
being positioned above said end portion of said dental implant.
53. The transition component of claim 52, further including a
registering section above said protruding non-round fitting for
ensuring alignment of a mating component on said protruding
non-round fitting.
54. The transition component of claim 52, wherein said tapering
segment and said third wall provide a locking taper.
55. The transition component of claim 52, wherein said tapering
section includes a lubricant.
56. The transition component of claim 52, wherein said end portion
of said implant includes a generally annular surface at an angle
with a central axis of said implant that is substantially less that
90.degree., said protruding section being directly below said
annular surface.
57. The transition component of claim 52, wherein said second wall
is substantially cylindrical and said transition component includes
a generally cylindrical portion between said threaded segment and
said tapering segment, said generally cylindrical portion of said
transition component and said second wall of said implant being
substantially the same diameter.
58. The transition component of claim 57, wherein said second wall
and said generally cylindrical portion provide an alignment of said
transition component on said implant.
59. The transition component of claim 52, further in combination
with an abutment for supporting an artificial tooth, said abutment
including a skirt portion which rests on, said end portion of said
implant and a non-round socket for receiving said protruding
non-round fitting, and means for axially retaining said skirt
portion on said end portion.
60. The combination of claim 59, wherein said transition component
includes an internally threaded hole and said retaining means is a
screw that is threaded into said internally threaded hole.
61. The combination of claim 59, wherein said transition component
and said abutment include means for registering said transition
component relative to said abutment.
62. A set of transition components for converting a
generally-cylindrical, subgingival type of dental implant having a
non-round fitting at its uppermost surface into a single-stage
dental implant having a body section for confronting said bone and
a head section attached to said body section for extending through
said overlying gingiva, said head section flaring outwardly and
including an end portion with an annular surface at predetermined
angle with respect to a central axis of said single stage implant,
said set comprising: a tubular transition component with a
non-round socket to mate with said non-round fitting of said
subgingival implant, said transition component having an exterior
surface that flares outwardly in substantially the same size and
shape as head section of said single-stage implant; and means for
axially retaining said tubular transition component on said
implant.
63. The transition components of claim 62, wherein said
predetermined angle is substantially less than 90.degree..
64. The transition components of claim 62, wherein said
predetermined angle is about 45.degree..
65. The transition components of claim 62, wherein said exterior
surface flares outwardly from a lowermost end to a maximum diameter
forming a first conical surface and then flares inwardly to a
smaller diameter near an uppermost end to form a second conical
surface.
66. The transition components of claim 65, wherein said annular
surface is along said second conical surface.
67. A set of components for making a subgingival dental implant and
a transgingival dental implant adapted for use with the same
restoration component for supporting a dental prosthesis, said
subgingival dental implant having a generally cylindrical body and
a non-round fitting at an uppermost surface of said body, said
transgingival dental implant having a body section for confronting
said bone and a head section attached to said body section for
extending through gingiva overlying said bone and flaring outwardly
away from said body section, said transgingival type of implant
having an internal bore extending into said head section, said set
comprising: a tubular component with a socket to mate with said
non-round fitting of said subgingival implant, said tubular
component having an exterior surface that flares outwardly in
substantially the same size and shape as head section of said
transgingival implant; a fastener for axially retaining said
tubular component on said subgingival implant, said fastener
including a first projection protruding above said tubular
transition component; and a transition component for insertion into
said internal bore of said transgingival type of implant, said
transition component including a second projection for extending
above said head section, and wherein said first and second segments
have substantially the same contour for mating with said
restoration component.
68. The conversion set of claim 67 wherein said head section of
said transgingival implant includes an end portion with an annular
surface at predetermined angle with respect to a central axis of
said single stage implant, said tubular component having a similar
annular surface.
69. The conversion set of claim 68 wherein said annular surface of
said transgingival implant and said annular surface of said tubular
component are capable of engaging said restoration component.
70. The conversion set of claim 67 wherein said first and second
projections each includes a non-round fitting for non-rotationally
engaging said restoration component.
71. The conversion set of claim 70 wherein said first and second
projections each includes an alignment region for registering said
restoration component thereon.
72. The conversion set of claim 67, wherein said bore of said
transgingival implant terminates at an opening at an upper portion
of said head section and is defined by first, second, and third
walls, said first wall having internal threads, said second wall
having a larger diameter than said first surface and being
substantially cylindrical, said second wall extending from said
first wall toward said end portion of said head section, said third
wall extending from said second wall to said opening, said third
wall flaring toward said opening to a diameter that is wider than a
diameter of said second wall.
73. The conversion set of claim 72, wherein said transition
component includes a threaded stem for mating with said internal
threads of said first wall.
74. The conversion set of claim 72, wherein said transition
component has a guiding section for mating with and fitting within
said second wall.
75. The conversion set of claim 72, wherein said transition
component has a tapered wall for mating with said third wall.
76. The conversion set of claim 75, wherein said tapered wall and
said third wall form a locking taper.
77. A temporary gingival forming component for a single stage
implant having a body for confronting said jawbone and a head
section terminating in an end portion at or below overlying
gingiva, said head section flares outwardly away from said body to
its maximum diameter near said end portion and said end portion
includes an annular surface which is at an angle substantially less
than 90.degree. with respect to a central axis of said implant,
said implant receiving a post for supporting artificial dentition
that extends beyond said head section of said implant, said
temporary gingival forming component comprising: a hollow body
section for fitting over said post; and a lower section attached to
hollow body section, said lower section having a first internal
surface for engaging said annular surface and a second internal
surface for contacting said head section at said maximum diameter,
said lower section having a smooth rounded exterior surface
extending upwardly from a lowermost extremity for engaging and
forming said overlying gingiva.
78. The temporary component of claim 77, wherein said lower section
of said gingival forming component further includes a third
internal surface extending below second internal surface.
79. The temporary component of claim 78, wherein said third
internal surface engages said head section below said maximum
diameter.
80. The temporary component of claim 77, wherein said lower section
is capable of receiving a gingival forming chemical.
81. The temporary component of claim 77, wherein said hollow body
section is separated from an exterior surface of said post by a
gap, said hollow body section being adapted to receive a cement
within said gap to attach said gingival forming component to said
post.
82. A temporary support post for a single stage implant having a
body for confronting said jawbone and a head section terminating in
an end portion at or below overlying gingiva, said head section
flares outwardly away from said body to its maximum diameter near
said end portion and said end portion includes an annular surface
which is at an angle substantially less than 90.degree. with
respect to a central axis of said implant, said implant receiving a
post for supporting artificial dentition that extends beyond said
head section of said implant, said temporary post for supporting a
temporary dentition comprising: a hollow body section for fitting
over said post and including a plurality of perforations, said
hollow body section being separated from said post by a gap, said
gap being accessible through said plurality of perforations and
receiving material that forms said temporary dentition; and a lower
section attached to said hollow body section, said lower section
having a first internal surface for engaging said annular surface
and a second internal surface for contacting said head section at
said maximum diameter.
83. The temporary component of claim 82, wherein said lower section
of said temporary post further includes a third internal surface
extending below second internal surface.
84. The temporary component of claim 83, wherein said third
internal surface engages said head section below said maximum
diameter.
85. The temporary component of claim 82, wherein said hollow body
section includes circumferential ribs extending along an outer
surface thereof.
Description
FIELD OF THE INVENTION
[0001] The invention relates generally to implants and, in
particular, a single-stage dental implant that promotes healing of
the gingiva and osseointegration simultaneously.
BACKGROUND OF THE INVENTION
[0002] It is becoming more common to replace a missing tooth with a
prosthetic tooth that is placed upon and attached to a dental
implant. The dental implant serves as the artificial root in that
it integrates with the jawbone. The prosthetic tooth preferably has
a size and a color that mimics the missing natural tooth.
Consequently, the patient has an aesthetically pleasing and
structurally sound artificial tooth.
[0003] Current methods by which the prosthetic tooth and implant
are completely integrated into the patient's mouth require six to
ten months, and sometimes longer, because two distinct,
time-consuming steps are involved. First, the implant is inserted
into the jawbone and covered by suturing the overlying gingival
tissue. Covering the implant with the overlying gingiva is needed
to minimize the likelihood of infection around the implant.
Covering the implant also helps to guard against any disturbances
of the implant that may slow its rate of osseointegration. The
implant then osseointegrates with the jawbone for a period, usually
in the range of three to six months.
[0004] After osseointegration is complete, the second step is
encountered in which the gingiva is again cut open and a healing
abutment is placed onto the implant. The overlying gingiva is
sutured to allow it to properly heal around the healing abutment.
Thus, when the prosthetic tooth is eventually placed upon the
implant, the gingiva nicely conforms around the prosthetic tooth.
However, it typically takes four to eight weeks before the gingiva
is healed and the prosthetic tooth can be placed on the implant to
complete the overall process. These implants can be referred to as
"subgingival implants."
[0005] Single-stage implants or "transgingival implants"
simultaneously promote osseointegration and the healing of the
gingiva. This is accomplished by providing an implant that has a
portion that integrates with the jawbone and a portion that extends
through the overlying gingiva so that the gingiva properly heals
therearound. Thus, the four to eight week gingival healing process
occurs during the three to six month period of osseointegration.
Consequently, the patient is fitted with a prosthesis in a shorter
period of time. And, the gingiva is lacerated and sutured one less
time compared with two-stage systems which reduces the trauma to
that region, the discomfort experienced by the patient, and the
overall cost because the number of dental procedures is
minimized.
[0006] It is sometimes desirable to convert a subgingival implant
to the configuration of a transgingival style or vice versa. For
example, if one style is best suited for installation in a first
site in a patient's jawbone, but another style is best suited for
installation in another site, the restoring dentist seeking to
fashion a bridge supported on implants installed in both sites
might prefer to convert one style to the other in order to make the
bridge using common components. Similarly, if a restoring dentist
has on hand implants of one style and components for a new improved
style become available, for reasons of economy it might be
desirable to convert the available implants to the new styles so
they can be used with the new components. However, known transition
components introduce gaps between the components and present
alignment problems for the restoration components.
[0007] Furthermore, during the preparation of dental restorations
supported on artificial roots implanted in living jawbone, it is
frequently useful to provide a temporary cover for a post or
abutment (that eventually holds the artificial dentition) supported
on a transgingival implant. It is also desirable to prevent the
gingival tissue from collapsing around the transgingival implant or
to maintain an opening in the tissue at least until temporary
dentition is made. This invention also relates to a temporary cap
useful to cover such abutments and posts for a transgingival
implant.
SUMMARY OF THE INVENTION
[0008] The single-stage dental implant is typically installed
through a ridge in the jawbone that is covered by gingival tissue.
The dental implant provides an artificial root on which a
prosthetic tooth is mounted to replace a missing tooth which
formerly emerged from the jawbone. The single-stage implant
comprises an anchoring portion for extending into and integrating
with the jawbone and an integral gingival section that extends
beyond the ridge of the jawbone. Because the gingival section is
integral with the anchoring portion, there is no seam in which
bacteria may collect to cause infections.
[0009] The implant has various embodiments with various internal
structures which allow the implant to be driven into the bone
tissue in the patient's mouth. These internal structures typically
engage a carrier that is delivered with the implant. Thus, the
clinician uses tools that engage the carrier to drive the implant
to the appropriate depth. After insertion, the clinician removes
the carrier from the implant and a cover screw is placed thereover.
The implant also has structural features enhancing its ability to
support the artificial dentition on the post.
[0010] The inventive single-stage system also includes conversion
components that allow a subgingival implant to have the same
contour and structure as a transgingival implant. To convert a
subgingival implant, a tubular member having an outer counter the
same as the gingival head section of the transgingival implant is
non-rotationally attached to the hexagonal fitting on the upper end
of the subgingival implant. The fastener holding the tubular member
on the implant extends above the tubular component and usually
contains a non-rotational fitting (e.g. a hexagon). To convert the
transgingival implant, a single transition component is threaded
into the bore of the transgingival implant. The upper part of the
transition component has the same contour as the portion of the
fastener (used with the tubular member) extending above the tubular
member. Thus, these conversion components provide a precise
configuration that is present on both a converted transgingival
implant and a converted subgingival implant which allows both to
use the same restoration components.
[0011] The inventive single-stage implant system further
contemplates novel components to mate with the posts of the
implants. The posts and abutments (hereinafter "posts" for
convenience) on which artificial teeth are mounted generally extend
supragingivally from a base at or beneath the gum surface to an end
that may be narrower than the base. One inventive cap is hollow and
open at least at its lower end so as to envelop the post in a
generally telescopic manner when placed over the post. The end of
the cap facing the base of the post is fitted with a rim enclosing
an annular hollow space so as to snap over the periphery of the
base when the cap encloses the post. When so fitted over the post,
the cap covers the post and prevents the gum tissue from collapsing
around the base of the post and top of the implant. It may also
maintain an opening through the gum tissue for use by the restored
tooth that is eventually mounted on the post. If it is desired for
the cap to function as a temporary tooth, a suitable temporary
cement can be used to fill the space between the cap and the post,
in which event the hole in the top of the cap will serve as a vent
for excess cement.
[0012] In another embodiment of the invention, the cap is open at
its top and has perforations through its sides. When this
embodiment is fitted over the post and covered with a tooth-shaped
shell filled with a suitable dental plastic material that can be
forced through the perforations into contact with the post and
allowed to harden in a short time, a temporary tooth in the shape
of the shell can be fashioned at chairside in the mouth of a
patient, or on a model of the patient's case out of the patient's
mouth. When the plastic material hardens, the shell can be removed,
and this tooth can be cemented to the post to function as a
temporary tooth which is cosmetically similar to adjacent
teeth.
[0013] The above summary of the present invention is not intended
to represent each embodiment, or every aspect, of the present
invention. This is the purpose of the figures and the detailed
description which follow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] In the accompanying drawings:
[0015] FIGS. 1a-1c are side, insertion end, and gingival end views
of an implant according to the present invention;
[0016] FIGS. 2a-2c are side, insertion end, and gingival end views
of an implant;
[0017] FIGS. 3 and 4 are side views of an implant with a roughened
outer surface;
[0018] FIGS. 5a-5c are side, insertion end, and gingival end views
of a wide-diameter implant;
[0019] FIGS. 6a-6d are side, section, head end, and insertion end
views of a cover screw;
[0020] FIGS. 7a-7d are side, section, head end, and insertion end
views of a cover screw;
[0021] FIGS. 8a-8c are side, head-end, and insertion-end views of a
cover screw;
[0022] FIGS. 9a-9d are a side view, supragingival end view,
insertion end view, and an assembly view of an abutment post for
supporting a dental prosthesis;
[0023] FIG. 10 is a side view of a gingival end of an implant with
a carrier attached thereto;
[0024] FIGS. 11a-11c are side, insertion end, and gingival end
views of an implant;
[0025] FIG. 12 is an enlarged view of the gingival end of FIG.
11;
[0026] FIGS. 13a-13c are side, longitudinal section, and top end
views of a mount body;
[0027] FIGS. 14a-14b are a mount screw and a head-end view for use
with the mount body of FIG. 13;
[0028] FIG. 15 is an exploded side elevation, partially in section,
view of a transition component and associated components for use
with a transgingival-style dental implant;
[0029] FIG. 16 shows the components of FIG. 15 assembled;
[0030] FIG. 17 is an exploded side elevation, partially in section,
of a transition component and associated components for use with a
subgingival-style implant;
[0031] FIG. 18 shows the components of FIG. 17 assembled.
[0032] FIG. 19 is a longitudinal section taken through the middle
of a cap embodying the invention;
[0033] FIG. 20 is a bottom plan view of the cap of FIG. 19;
[0034] FIG. 21 is an enlarged view of the lower right-hand corner
of the cap of FIG. 19;
[0035] FIGS. 22a-22c are a side elevation, a top perspective, and a
bottom perspective view of a modified cap embodying the
invention;
[0036] FIGS. 23a-23c are a vertical section, a top perspective, and
a bottom perspective view taken through the middle of the cap of
FIG. 22;
[0037] FIG. 24 is a side elevation, partially in section, of an
implant system using the cap of FIGS. 22 and 23; and
[0038] FIG. 25 is the same sectional view of the cap as in FIG. 23
with the addition of a diagrammatic illustration of an artificial
tooth shell around the cap.
DETAILED DESCRIPTION OF THE DRAWINGS
[0039] FIGS. 1a-1c illustrate an implant 10 having a main body 12
with a threaded outer surface 13. The threaded outer surface 13
includes a self-tapping region with incremental cutting edges 14 at
an apical end 16 of the main body 12. These incremental cutting
edges 14 are defined in detail in U.S. Pat. No. 5,727,943, entitled
"Self-Tapping, Screw-Type Dental Implant" which is herein
incorporated by reference in its entirety.
[0040] An axial opening 18 in a gingival end 20 of the main body 12
has three distinct zones proceeding from the uppermost edge of the
gingival end 20 into the interior of the implant 10. An
inwardly-tapering zone 22 is followed by a substantially
cylindrical zone 24 which, in turn, is followed by an
internally-threaded zone 26.
[0041] An outer surface 28 tapers downwardly from the uppermost
edge of the gingival end 20 to a maximum diameter region 30. On the
outer surface 28 between the uppermost edge of the implant 10 and
the maximum diameter region 30 is a set of flat surfaces 32 shown
here in a commonly-used hexagonal configuration. This set of flat
surfaces 32 can be engageable with a tool that screws the implant
10 into the bone tissue. Alternatively, the set of flat surfaces 32
may be engaged by a carrier that is delivered with the implant 10
such that the clinician applies torque to the carrier which then is
transferred into the implant 10 (see FIG. 10). The distance 34
between two parallel flat surfaces 32 can be made larger than the
major diameter of the threads defining the threaded outer surface
13 of the main body 12 of the implant 10.
[0042] With regard to the details of the structure in the gingival
end 20, each of the three zones 22, 24 and 26 of the opening 18 has
a unique function. Each function is useful in connection with
several different components of the system. These components will
be discussed with reference to FIGS. 6-10.
[0043] FIGS. 2a-2c disclose an implant 36 that differs from the
implant 10 of FIG. 1 in the details of cutting edges 14' and the
contours of the threads defining the threaded outer surface 13'.
When viewed in cross-section, the threaded outer surface 13' is
non-circular in the region of the threads and/or the troughs
between the threads. This type of thread structure is defined in
detail in U.S. application Ser. No. 08/782,056, filed Jan. 13,
1997, entitled "Reduced Friction, Screw-Type Dental Implant" which
is herein incorporated by reference in its entirety. However, the
zones 22, 24, and 26 of the opening 18 and the structure at the
gingival end 20 are the same in the implant 36 as the implant 10 of
FIGS. 1a-1c.
[0044] In FIG. 3, an implant 38 has a roughened outer threaded
surface 40. The roughened outer threaded surface 40 may be produced
through grit blasting or acid etching, or a combination of these
two procedures. Exemplary processes of grit blasting and acid
etching are described in U.S. Pat. Nos. 5,607,480 and 5,603,338
which are herein incorporated by reference in their entirety. The
roughened outer threaded surface 40 enhances the osseointegration
process. However, the gingival end 20 has a smooth outer surface
such that it will not irritate the soft gingival tissue that
contacts the gingival end 20.
[0045] In FIG. 4, the implant 38 of FIG. 3 is illustrated having a
roughened outer threaded surface 40 that extends into the gingival
end 20. Thus, a transition line 39 between the roughened outer
threaded surface 40 and the smooth surface at the gingival end 20
is located within the second zone 24. The positioning of the
transition line 39 closer to the gingival end 20 may be useful in
situations where more of the gingival end 20 is inserted into the
bone.
[0046] In FIGS. 5a-5c, an implant 41 having a wide diameter in the
region of its roughed outer threaded surface 42 is illustrated. The
diameter is in the range from about 4.5 mm to about 6.0 mm with the
diameter of 5.0 mm being a fairly common dimension for a wide
diameter implant. Such an implant 41 is useful to engage one or
both cortical bones to provide enhanced stability, especially
during the period of time after installation. The gingival end 20
again is structurally the same as the implants of FIGS. 1-4.
[0047] Several types of components are attachable to the implants
of FIGS. 1-5. FIGS. 6-8 illustrate various types of cover screw
that are inserted into the implant 10. Referring initially to FIGS.
6a-6d, a cover screw 44 has a head 46, an externally-threaded
insertion end 48, and a cylindrical shaft 50 between the head 46
and the insertion end 48.
[0048] In use, the insertion end 48 of the cover screw 44 is
threaded into the internally-threaded zone 26 of the opening 18 of
the implant 10. The cylindrical shaft 50 fits within the
cylindrical zone 24 of the opening 18 of the implants in FIGS. 1-5.
The mating of the cylindrical zone 24 and cylindrical shaft 50
provide stability during insertion of the cover screw 44 into the
opening 18. The head 46 has a reentrant under-surface 52 which
covers the outer surface 28 and the flat surfaces 32 of the implant
when the cover screw 44 is placed on the implant of FIGS. 1-5. The
head 46 also has a bore 54 with flat surfaces 56 for engaging a
tool, such as an Allen wrench, that turns the cover screw 44 into
the internally-threaded zone 26 of the implant.
[0049] FIGS. 7a-7d illustrates a cover screw 60 having a head 62, a
threaded insertion end 64, and cylindrical shaft 66 between the
head 62 and the insertion end 64. The threaded insertion end 64
threadably engages the internally threaded zone 26 of the implants
of FIGS. 1-5. The cylindrical shaft 66 resides within the
cylindrical zone 24. The head 62 includes an undercut 67 that
covers the outer surface 28 and the flat surfaces 32 of the
implant. The head 62 also has a bore 68 with a region for engaging
a tool that installs the cover screw 60 into the implant. The
primary difference between the cover screw 60 and the cover screw
44 of FIG. 6 is that the head 62 of the cover screw 60 has an
increased height such that it would extend further above the
gingiva.
[0050] In FIGS. 8a-8c, a cover screw 70 has a head 72 with a
tapering side-surface 74 for engaging the tapered zone 22 of the
opening 18 of the implants of FIGS. 1-5. The upper surface of the
head 72 would be approximately flush with the uppermost edge of the
gingival end 20 of the implants. The tapering surfaces of the
tapered zone 22 and the side-surface 74 are preferably tapered on
the same angle suitably to provide a locking taper (e.g. about
18.degree.) when those surfaces are engaged. A cylindrical shaft 78
is placed between the head 72 and a threaded insertion end 79.
[0051] The head 72 has a bore 76 with flat surfaces for engaging a
wrench that turns the cover screw into the internally-threaded zone
26 of the opening 18. The cover screw 70 of FIG. 8 may be
especially suitable for use with wide-diameter implants (e.g. FIG.
5), where the cover screw design of FIGS. 6 and 7 might be
excessively bulky.
[0052] In FIGS. 9a-9d, an abutment post 80 includes four zones in a
longitudinal sequence, namely, a supragingival zone 82, a
locking-taper zone 84, a substantially cylindrical zone 86, and an
externally-threaded zone 88. The last-mentioned three zones 84, 86
and 88 correspond, respectively, to the zones denominated 74, 78
and 79 in the cover screw 70 of FIG. 8. In use, the abutment post
80 is attached to one of the implants of FIGS. 1-5 by inserting the
externally-threaded zone 88 into the internally-threaded zone 26 of
the opening 18 and rotating the post 80 until the tapered zones 84
and 22 engage and lock together. During the process of turning the
post 80 into the implant, the cylindrical zones 24 and 86 provide
axial stability that prohibits cross-threading the threaded
surfaces of zones 88 and 26. The axial stability provides for true
engagement of the tapering surfaces 84 and 22. The supragingival
zone 82 has longitudinally-extending grooves 89 that are useful for
engaging a tool to turn the post 80 into the implant. These grooves
84 are also helpful to hold a cemented prosthesis against rotation
on the post 80.
[0053] To ensure that the tapering surfaces 84 and 22 do not resist
in providing the required axial tension strain from the engagement
of the threaded portions 88 and 26, the tapering surfaces 84 and 22
may be provided with a lubricant to reduce the friction between
them. Biocompatible lubricants may be provided. Alternatively, the
plating of one of the tapered surfaces, preferably the tapered
surface 84 of the post 80, with gold may provide the necessary
friction-reducing means. This type of friction-reducing plating is
described in U.S. Provisional Application Serial Nos. 60/059,307
and 60/043,106, filed Sep. 17, 1997 and Apr. 17, 1997,
respectively, and entitled "Dental Implant System having Improved
Stability" and "Low Insertion Torque Screws for Use With Dental
Implants", respectively, which are herein incorporated by reference
in their entirety. Thus, the locking tapers may be lubricated
through traditional biocompatible lubricants or metallic molecules
which serves as a solid type of lubricant.
[0054] As shown in FIG. 9d, when the post 80 is assembled on an
implant, such as implant 41 of FIG. 5, the flat surfaces 32 are
outside the post 80. Thus, the flat surfaces 32 also serve the
function of engaging a prosthesis against rotation on the implant,
independent of any engagement between the prosthesis and the post
80.
[0055] As an alternative post configuration, the post may be made
of two pieces, a tubular member to mate with the outer surface 28
and a threaded post that is inserted through the tubular member and
holds the tubular member on the implant. Such a two-piece abutment
system is disclosed in U.S. Ser. No. 08/729,869, filed Oct. 15,
1996, entitled "Two-Piece Dental Abutment," which is herein
incorporated by reference in its entirety.
[0056] In FIG. 10, a carrier for the implants of FIGS. 1-5 includes
a main body 90 that has a structure 92 for engaging a driving tool
that provides torque to the combination of the carrier and the
implant. Although that structure 92 is illustrated on the exterior
surfaces of the main body 90, that structure may be located on the
interior surface of the main body 90 as well. The main body 90
includes an extending portion 94 that has at its lowermost portion
a diameter that is narrow enough to be inserted into the
cylindrical zone 24 of the gingival end 20 of the implant.
[0057] The main body 90 includes an overlapping region with an
internal surface 95 that fits over the flat surfaces 32 of the
gingival end 20. The internal surface 95 has the cross-sectional
shape of a hexagon to mate with the hexagonal shape of the flat
surfaces 32.
[0058] Between the overlapping region and the extending portion 94
is a tapered region 96 that fits the tapered zone 22 of the
gingival end 20. However, the tapered region 96 does not need to
engage the tapered zone 22. Although not shown, the extending
portion 94 and the shank region 96 have an axially extending slot
whose function is described below.
[0059] The extending portion 94 and shank portion have internal
threads 97 that mate with screw 98 that is inserted into the bore
of the main body 90. When the screw 98 is inserted into the
internal threads 97, the extending portion 94 expands outwardly so
as to become in tight frictional engagement with the cylindrical
zone 24 of the implant. This process of affixing the carrier onto
the implant is typically performed at the manufacturer's facility
such that the carrier and the implant are delivered to the
clinician as one unit. When the clinician uses the combination of
the carrier and the implant, he or she places the apical end 16 of
the implant 10 (see e.g. FIG. 1) into a bore in the jawbone. The
clinician then uses a tool that engages the structure 92 on the
main body 90, to turn the implant (with its self-tapping threads)
into the bore. When the implant is inserted to the proper depth,
the clinician then engages the non-circular bore 99 of the screw 98
with a tool and removes it from the implant. To ensure that the
torque applied to the screw 98 during its removal does not rotate
the entire implant, the direction of the thread of the screw 98 is
chosen such that the applied torque would cause the implant to be
further inserted into the bone. However, since the insertion of the
implant would require more torque than the torque necessary to
remove the screw 98, the implant remains motionless while the screw
98 is removed.
[0060] The implant 110 of FIGS. 11a-11c differ from implants of
FIGS. 1-5 in that the implant 110 has a cylindrical zone 124 that
is fitted with shallow helical grooves 125 in the surface of the
wall defining the cylindrical zone 124. Thus, a portion of this
wall defining the cylindrical zone 124 remains intact as it forms
the lands between adjacent grooves 125. Furthermore, the implant
110 lacks the flat surfaces on its outer surface that form the
hexagon on the gingival end as is shown in the implants of FIGS.
1-5. In other words, the outer surface 128 of the implant 110 is
smooth. However, the remaining structures of implant 110 are the
same as implant 10 of FIG. 1 and, thus, those remaining structures
are now denoted by a 100-Series reference numeral.
[0061] Referring now to FIG. 12, the cylindrical zone 124 of the
opening 118 is shown in detail. Four grooves 125 form a multi-lead
thread having a relatively large pitch. The grooves 125 do not cut
deeply into the cylinder wall so that they leave relatively wide
lands 127 between adjacent grooves 125 thereby preserving the
portion of the cylinder wall intact. In one practical embodiment of
the implant 110, the axial length of the cylindrical zone 124 is a
little more than 1 mm and the pitch of the threads formed by the
grooves 125 about 1 mm. Thus, a single turn of a screw threadably
mating with the grooves 125 serves to insert or remove that screw
from the zone 124.
[0062] Even with the structure of the cylindrical zone 124 of FIGS.
11-12, the implant 110 can cooperate with the covers screws of
FIGS. 6-8, and with the abutment post 80 of FIG. 9. Additionally,
it serves functions related to the purposes of the implant mount
and screw shown in FIGS. 13 and 14.
[0063] The implant mount 170, or carrier, shown in FIGS. 13a-13c
has a head section 172 of non-round (here hexagonal) cross-section
suitable for engaging with a socket wrench. The mount 170 has a
through passage 174 extending from the head section 172 through a
tail end 176. The through passage 174 has internal threads 178 in
the head section 172. The tail end 176 has external threads 180
suitable for engaging the grooves 125 of the multi-lead thread in
the cylinder zone 124 of the implant 110 of FIGS. 10-11.
Longitudinally-directed slots 182 in the tail end 176 extend toward
the head section 172. As seen best in FIG. 13C, four slots 182 are
used in the illustrated embodiment, forming four fingers 183 in the
tail-end 176. These slots 182 may all be the same length, or they
may have different lengths. In one embodiment, one pair of opposing
slots are longer than the intervening pair. Immediately inside the
tail end 176, the passage 174 is partially obstructed with wedge
blocks 184, one of which is attached to each finger 183.
[0064] Between its ends, the mount 170 has a radially-extending
flange 185 similar to the head 46 of the cover screws of FIGS. 6
& 7. The flange 185 includes a reentrant under-surface 187 that
engages the outer surface 128 of the gingival end 120.
[0065] The mount screw 190 of FIG. 14 has an externally-threaded
section 192 between its head end 194 and its tail end 196. A
cylindrical shaft 198 extends between the threaded section 192 and
the tail end 196 suitably dimensioned for fitting within the
passage 174 of the implant mount 170. At the tail end 196, the
shaft 198 has a tapered end-section 197 for engaging between the
wedge blocks 184 of the implant mount 170. In its head end 194, the
screw 190 has a non-round (here shown as hexagonal) socket 200 for
engaging a wrench, such as an Allen wrench.
[0066] In use, the implant mount 170 of FIG. 13 is inserted through
the implant passage 118 and threaded via the threads 180 at its
tail end 176 into the threaded cylindrical zone 124 of the implant
110. In a preferred embodiment, approximately one turn is required
to seat the flange 185 of the implant mount 170 over the outer
surface 128 of the implant 110 using a torque of about 10 N-cm. The
mount screw 190 is then inserted through the passage 174 of the
implant mount 170 and its threaded section 192 is engaged in the
internal threads 178 in the head section 172 of the mount 170. A
suitable wrench engaged in the socket 200 is useful to drive the
mount screw 170 into and between the wedge blocks 184 and thereby
apply a radially-directed force to spread the tail end 176 within
the cylindrical zone 124 using a torque of about 15 N-cm.
[0067] The implant 110 of FIG. 11 with the implant mount 170 and
screw 190 (FIGS. 13 and 14) installed as herein described are
carried to the site in the mouth of the patient. The implant 110 is
installed in the prepared site with a torque required to overcome
the cutting of the bone at the self-tapping region. Such torque is
generally less than about 40 N-cm. Tests applying torque forces in
excess of 100 N-cm have shown that the fingers 184 may be expected
to break when the torque exceeds about 120 N-cm which is a far
greater torque than would be encountered in a real-life
situation.
[0068] After the implant 110 has been installed in the patient's
bone, the mount 170 is easily removed by loosening the screw 190
and turning the mount 170 in reverse by approximately one turn to
release it from the implant 110. The invention also contemplates an
embodiment where the screw 190 is held captive in the passage 174
of the mount 170 such that both pieces remain together during their
removal from the implant.
[0069] With regard to the conversion between subgingival and
transgingival implants, it is highly desirable for successful
dental restoration that the components of a restoration system be
precisely dimensioned and that dimensional precision be maintained
at every stage in the process of constructing the restoration. For
example, implants of the subgingival style are commonly fitted at
their occlusal ends with an anti-rotational connecting element for
coupling a transgingival component to the implant in a manner that
prevents the component from rotating on the implant, around the
axis of the implant. These anti-rotational connection elements
usually take a hexagonal form, although octagonal forms are also in
use. Because of manufacturing tolerance limitations, it is
difficult to make hexagonal (for example) posts and sockets that
will fit together so tightly that they will not allow some little
amount of relative rotation between the connected implant and
component. The degree of tightness required to eliminate all
relative rotation would make connecting and disconnecting these two
parts in the mouth of a patient so difficult that the patient would
be unacceptably uncomfortable. A solution to this problem is
described in the assignee's copending U.S. patent application Ser.
No. 08/451,083, filed May 25, 1995, for "Anti-rotational Connecting
Mechanism," now U.S. Pat. No. 5,725,375.
[0070] Experience has shown that available transition components
tend to leave a small gap extending part-way around the periphery
of the implant surface. This is believed to be due, at least in
part, to the difficulty of accurately attaching restoration
components to the transition component. This in turn makes it
difficult to achieve and maintain precise axial alignment of the
implant, the transition component and the restoration component.
Accordingly, in addition to the inventive transgingival style of
implant, the present invention addresses the alignment, tolerance,
and gap problems as will be shown in FIGS. 15 and 16.
[0071] FIGS. 15 and 16 relate to conversion components for
converting between a subgingival and transgingival implant. A
transition component 240 has a lower section designed to fit into
the implant 110 of FIGS. 11-12. This lower section includes a
tapered zone 242, an intermediate zone 244 and an externally
threaded zone 246 designed to fit in the corresponding zones 122,
124, and 126 of the implant bore 118. Specifically, the threaded
zone 246 screws into the innermost zone 126 of the implant, the
intermediate zone 244 mates with the intermediate zone 124 of the
bore 118, and the tapered zone 242 seats in the outermost zone 122
of the implant bore 118. A locking taper is formed by the engaging
side walls of the zones 122 and 242, and thus only a short thread
section 246 is needed on the distal end of the transition
component.
[0072] The transition component 240 also: has an upper section that
extends beyond the occlusal end of the implant. This upper section
includes a hexagonal anti-rotation zone 250 and a locator zone 252,
extending in sequence supragingivally from the implant when the
transition component 240 is installed in the bore 118. The axial
length of the locator zone 252 is preferably larger than the axial
length of the anti-rotation zone 250. The locator zone 252 is
preferably round in cross-section, and smaller in cross-sectional
size than, the anti-rotation zone 250.
[0073] A hollow abutment 260, which performs the function of a
non-rotating cylinder used to support an artificial tooth, fits
over the upper section of the transition component 240 and the
occlusal surface of the implant 110. The inside surface of the
abutment 260 includes an upper section 262 and a lower section 264
separated by a flange 266. The upper section 262 receives the head
of a retainer screw 267, with the screw head resting on the
shoulder formed by the upper surface of the flange 266. The lower
section 264 includes a locator zone 268 above the usual hexagonal
socket 270, and a flared skirt 272 extends outwardly and downwardly
from the bottom edge of the socket 270 to the bottom periphery of
the abutment. The inside surface of the skirt 270 preferably flares
on an angle (measured from the longitudinal axis through the
implant and attached components) that is a little smaller than the
slope angle of the outer surface 128 of the implant 110, so that
the initial contact between these two surfaces occurs at the bottom
edge of the skirt 272.
[0074] When the abutment 260 is fitted to the transition component
240, the locator zone 268 of the abutment makes first contact with
the locator zone 252 and serves to align the abutment axially with
the transition component. Because the two mating locator zones 252
and 268 are both cylindrical and very close to the same size, the
abutment 260 can be turned around the common axis until the
anti-rotation zones 250 and 270 are in register. The abutment 260
can then be seated accurately on the transition component 240, and
the retainer screw 267 can be screwed into the bore 254 and
tightened to seat the skirt 272 on the outer surface 128 of the
implant 110.
[0075] Because the mating locator zones 268 and 272 guide and align
the abutment 260 as it is fitted over the transition component 240,
the abutment 260 is accurately seated on both the transition
component 240 and the outer surface 128 of the implant 110, thereby
avoiding any microgaps at the interface between the abutment and
the implant. As described above, precise alignment is further
facilitated by the fact that the outer periphery of the skirt 272
makes first contact with the outer surface 128 of the implant 110,
and further tightening of the screw 267 increases the annular area
of that contact.
[0076] The tube 280 shown in FIGS. 15 and 16 is a known component
used to make an artificial tooth using the lost-wax process. The
tube 280, which is typically made of a material that is burned away
in the course of the lost-wax process, fits over the abutment 260
down to the skirt 272. A waxing sleeve 282 is provided to cover the
skirt.
[0077] The invention can be adapted to modification of a
subgingival-style implant 284, as is shown in FIGS. 17 and 18,
where parts common with FIGS. 15 and 16 bear the same reference
characters. The subgingival-type dental implant 284 is indicated in
part under an abutment ring 286 fitted non-rotationally to the
anti-rotation (e.g., hexagonal) fitting 288 of the implant 284.
This abutment ring 286 has an exterior side surface 289 that mimics
the side surface of the transgingival section 120 of the
transgingival implant 110 shown in FIGS. 11-12 , and a sloping top
surface 290 which mimics the sloping outer surface 128 of the
transgingival implant 110.
[0078] An abutment screw 291 attaches the abutment ring 286 to the
implant 284. This screw 291 has a threaded stem 292 which engages
the usual threaded bore of the implant 284. Above the stem 292,
cylindrical and tapered head sections 293 and 294 engage
corresponding interior surfaces of the abutment ring 286. The
portion of the screw head that projects above the abutment ring 286
is identical to the upper section of the transition component 240
described above. In other words, the head of the screw 291 includes
a locater region 295 and an anti-rotation 296 (e.g. hexagonal boss)
that are similar to locater zone 252 and anti-rotation zone 250 of
the transition component 240. All the other parts shown in FIGS. 17
and 18 are the same as the corresponding parts in FIGS. 15 and 16.
Thus, the abutment 260 and the tube 280 can be used with the
subgingival implant 284 after it has been fitted with ring 286.
[0079] FIGS. 19-25 relate to caps which engage the post of a
transgingival implant. In the first embodiment of the invention
shown in FIGS. 19-21, a cap 310 has a generally cylindrical-shaped
outer sidewall 312 and a tapered inner sidewall 314. This cap 310
has an open bottom 316 bounded by a rim 318 enclosing an annular
channel 320. The outer sidewall 310 turns inward at the bottom 311
toward the rim 318. At the top 322 the cap has a dome-shaped top
wall 324 with a hole 326 through it. The cap is preferably made of
a resilient polymeric material that retains its shape, such as
"Delrin."
[0080] In a second embodiment of the cap invention shown in FIGS.
22-24, a cap 330 has an open bottom 331 bounded by a rim 333
enclosing an annular channel 335 like the same parts of the cap 310
in FIGS. 19-21. The top 332 of the cap 330 is open and surrounded
by an annular rim 334. The inwardly-tapering bottom portion 337 of
the sidewall has an upwardly-facing annular shoulder 328 at its
upper end. Between this shoulder 328 and the top rim 334 are
several additional rims 336, 338 and 340, which decrease
progressively in diameter, as shown, from the shoulder 328 to the
top rim 334. The shoulder 328 has the largest outer diameter, and
the top rim 334 has the smallest outer diameter. A series of
generally tubular sidewall sections 342, 344, 346 and 348 are
fixed, respectively, between the shoulder 328 and the adjacent rim
336, then rim 336 and rim 338, then rim 338 and rim 340, and
finally rim 340 and rim 334. The diameters of these sidewall
sections decrease progressively from the shoulder 328 to the top
332 of the cap 330, so that the overall shape of the cap 330 is
tapered in diameter from the lower opening 316 to the upper opening
332. Each sidewall section has perforations 349 through it.
[0081] The caps 310 and 330 of the invention are fitted to the
previously-described implants of FIGS. 1-5, 11-12, and 15-18, which
will be generically called dental implant 350, by forcing the rims
318 and 333 over the peripheral surface 354 at the bottom of an
expanding sloping surface 352 at the top of the implant 350. The
annular channels 320 and 335 have a shape complementary to that of
the implant 350 so the upper portions of the channels 320 and 335
make contact with the sloping surface 352, while the lower portions
of the channels 320 and 335 fit against the upper portion of an
inwardly tapering surface 355 directly beneath the rim 354. To
enable this lowermost portion of the cap to pass the rim 354 of the
implant, the caps are preferably made of a resilient material so
that downward pressure urging the lower rims of the cap 310 and 330
against the sloping implant surface 352 cams the rim 318 outwardly,
thereby temporarily expanding the diameter of the bottom opening of
the cap 330 until the rim 318 clears the implant rim 354. The
resilience of the cap 330 then causes the rim 318 to snap back to
its original diameter, against the inwardly tapering surface 355
beneath the rim 354. It will be appreciated that this same type of
"snap action" may be used to hold the cap in virtually any undercut
surface configuration near the top of an implant. As can be seen in
FIG. 24, in its final installed position the cap 330 surrounds a
post 356 that is in place on the implant 350.
[0082] In an alternative embodiment, the rims 318 and 333 can have
a cylindrical internal lower configuration instead of the conical
internal configuration. In this embodiment, the rims 318 and 333 of
the caps 310 and 330 would engage the implant 350 along the upper
sloping surface 352 and the small cylindrical band of the implant
(at its widest diameter) just above the inwardly tapering surface
355. This band is usually about 0.004 in to 0.010 inch in height,
although it could be made larger. Thus, the rims 318 and 333 of the
caps 310 and 330 will have an internal cylindrical section with a
similar length to engage the cylindrical band on the implant.
Alternatively, the internal cylindrical section may be longer such
that it extends below the cylindrical band on the implant 350 but
does not engage the inwardly tapering surface 355 of the implant
350.
[0083] The cap 310 can be used by itself as a temporary tooth. The
clinician applies a cement to the inside surface of the cap 310 and
places it on the post. The excess cement then can vacate the cavity
under the cap 310 through the hole 326. Because the cap 310 by
itself serves as a temporary tooth and is made of relatively
inexpensive plastic materials, the invention contemplates producing
the cap in various sizes and shapes to generally mimic the outer
contours of natural teeth. Thus, the clinician would select the
size and shape that would best correspond to the conditions in the
patient's mouth. Alternatively, the cap 310 could be modified by
the clinician to produce a more esthetically pleasing contour.
Furthermore, cap 310 can be simply used without cement for a short
time (less than two days for example) to get the patient from the
periodontist to the restorative dentist.
[0084] Also, the cap 310 can form the gingiva at its bottom 311.
While in some instances a clinician will place the implant 350 such
that its upper sloping surface 352 is at or above the outer
gingival surface, some clinicians may place the implant 350 such
that its upper sloping surface 352 is well below the gingival
surface. Thus, the cap 310 may engage and form the gingiva for 2 mm
to 3 mm above its lowermost surface.
[0085] Because the cap 310 will form a ring-shaped cavity in the
gingiva adjacent to and around the inwardly tapering surface 355,
the cap 310 is useful prior to taking an impression because it is
beneficial to slightly move the gingival tissue away from the
implant 350 before the impression process. Thus, the impression
material can flow into this ring-shaped cavity to obtain a better
impression of the region along the inwardly tapering surface 355 of
the implant 350. While this process of displacing the gingival
tissue occurs after the cap 310 has been positioned on the implant
for some time (e.g. one day to one week), it can be expedited to
just a few minutes by dipping the bottom 311 of the cap 310 in
gingival retraction chemicals which results in the gingiva
tightening and pulling away from the implant 350. Thus, the
ring-shaped cavity is created due to the mechanical action of the
cap 310 and the chemical action of the gingiva retraction chemical.
Furthermore, it is possible to produce the cap 310 or just its
bottom 311 from a porous material to enhance the ability of the cap
to retain the gingival retraction chemical prior to its release
into the gingival tissue.
[0086] To achieve a temporary tooth that is cosmetically pleasing
and can last for several months, the cap 330 of FIGS. 22-23 should
be used, as is illustrated in FIG. 24. An appropriately-shaped
shell 360, chosen to mimic the tooth being restored, is filled
(wholly or partially as desired) with a quantity of a dental
plastic material (e.g., acrylic) that hardens slowly, and the
"filled" shell is placed over the cap as is illustrated in FIG. 25,
and manipulated to force the plastic material (not shown in FIG.
25) through the perforations 349 into contact with the post 356.
The spaces between the shell 360 and the cap 330, and between the
cap 330 and the post 356 (not shown in FIG. 25) will be filled with
the hardening plastic material. In practice, the clinician
preparing the temporary tooth will gently seat and remove the shell
360 and the cap 330 with the hardening material around the post 356
while the plastic material hardens. When the plastic material has
hardened, that person will remove this assembly from the post for
final preparation of the temporary tooth. If the tooth is being
prepared in patient's mouth where the site has one or two adjacent
teeth, it may be desired to remove the rim 333 of the cap 330 from
the implant 350, at least until preparation of the tooth is
completed. If the tooth is being prepared on a model outside the
patient's mouth, where the site can be isolated, the rim 333 can be
usefully retained, because the final temporary tooth need not
extend below the implant rim 354 (and the hardening of the
temporary tooth material around the cap 330 may reduce the
flexibility of the rim 333). In either case, in the final
preparation of the tooth, the shell 360 may be removed and the
hardened plastic material may be shaped and polished, and then
cemented in place on the post 356 with a suitable dental cement. It
will be appreciated that FIG. 25 is not drawn to scale. In
practice, the shell may be closer to the post than this
illustration shows it. While no acrylic (or other suitable
tooth-forming material) has been illustrated, such materials are
well-known in the dental art.
[0087] The cap 330 may be adjusted in length to match the length of
the post 356 by cutting the cap 330 at the top of any of the
intermediate rims 336, 338 or 340. FIG. 24 shows a post 356 which
extends to the uppermost rim 334 at the top opening 332. If a
shorter post is used, the cap 330 can be shortened to match the
post by removing that portion of the cap 330 above the first rim
340 beyond the top of post. Preferably, the rims 336, 338 and 340
would be positioned to correspond to the common sizes in which
posts are available.
[0088] The invention is not limited to the physical configurations
of the implant and the caps that are illustrated herein by way of
example. The dental arts include a wide variety of implants and
posts and abutments designed for use with them. The invention is
intended to apply to all such to which it can be adapted.
* * * * *