U.S. patent number RE35,784 [Application Number 08/587,133] was granted by the patent office on 1998-05-05 for submergible screw-type dental implant and method of utilization.
This patent grant is currently assigned to Vent-Plant Corporation. Invention is credited to Leonard I. Linkow, Anthony W. Rinaldi.
United States Patent |
RE35,784 |
Linkow , et al. |
May 5, 1998 |
**Please see images for:
( Certificate of Correction ) ** |
Submergible screw-type dental implant and method of utilization
Abstract
A submerigible screw-type implant includes a longitudinal
channel which directs bone chips towards the base of a bore in the
patient's bone in which the implant is installed. These bone chips
promote autogenous rapid regrowth of new bone to securely anchor
the implant in place. In order to be able to position the implant
at the most advantageous angle at the edentulous sight, angled
abutments for supporting an artificial tooth structure or angularly
adjustable abutments are provided. The angularly adjustable
abutments may be in the form of a ball and socket joint in which
the socket includes an inner casing having a peripheral extension
that acts to lock the joint at the desired angle. Also, the support
for an artificial tooth may include a shock-absorbing cushion to
prevent some of the forces of mastication from disturbing the
implant.
Inventors: |
Linkow; Leonard I. (New York,
NY), Rinaldi; Anthony W. (Philadelphia, PA) |
Assignee: |
Vent-Plant Corporation
(Philadelphia, PA)
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Family
ID: |
27362652 |
Appl.
No.: |
08/587,133 |
Filed: |
January 16, 1996 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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771398 |
Oct 2, 1991 |
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25942 |
Mar 16, 1987 |
4842518 |
Jun 27, 1989 |
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904381 |
Sep 4, 1986 |
4713004 |
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Reissue of: |
319651 |
Mar 6, 1989 |
04932868 |
Jun 12, 1990 |
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Current U.S.
Class: |
433/174 |
Current CPC
Class: |
A61C
8/0018 (20130101); A61C 8/0022 (20130101); A61C
8/005 (20130101); A61C 8/0053 (20130101); A61C
8/0074 (20130101); A61C 8/008 (20130101); A61C
8/0086 (20130101); A61C 8/0068 (20130101); A61C
8/0059 (20130101); A61C 8/006 (20130101); A61C
8/0069 (20130101) |
Current International
Class: |
A61C
8/00 (20060101); A61C 008/00 () |
Field of
Search: |
;433/173,174 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0 139 052 |
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May 1985 |
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EP |
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2085013 |
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Nov 1971 |
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FR |
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30 43 336 C2 |
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Aug 1981 |
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DE |
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30 27 138 A1 |
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Dec 1981 |
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DE |
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32 41 963 C1 |
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Apr 1984 |
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DE |
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85 23 007.3 |
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Nov 1985 |
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DE |
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1291470 |
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Oct 1972 |
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GB |
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1352188 |
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May 1974 |
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GB |
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1565178 |
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Apr 1980 |
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GB |
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2119258 |
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Nov 1993 |
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GB |
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Other References
Plaintiff' Memorandum of Points and Authorities in Opposition to
Defendants' Motion to File Amended Counterclaim, pp. 1-8, and Dr.
Linkow's Declaration executed Jan. 19, 1995, pp. 1-11, submitted in
support thereof with Exhibits A-F. .
Defendants' Memorandum of Points and Authorities in Reply to
Opposition to Defendants' Motion for Leave to File Amended
counterclaim, pp. 1-10, and Dr. Niznick's Declaration executed Jan.
30, 1995, pp. 20-29, submitted in support thereof with Exhibits
A1-A2 and B1-B5. .
Ralph V. McKinney, Jr., "Endosteal Dental Implants", Chapter 22,
entilled The vent-Plant Osseointegrated Compatible Implant System,
by Drs. Linkow and Rinaldi, published by Mosby Year Book, 1991,
Cover pages and pp. 266-267. .
Videotape of Dr. Leonard Linkow's lecture on implantology at
Harvard University in the mid 1980s. .
Drs. Leonard I. Linkow and Anthony W. Rinaldi, "The International
Journal of Oral & Maxillofacial Implants", special reprint,
vol. 3, No. 2, 1988, Cover page and pp. 109-122. .
Letter from Mark D. Friedman of Core-Vent Bio-Engineering to Paul
G. Gagne, Esq., Re: Rinaldi et al. v. Integrated Seminars, Inc., et
al., dated Feb. 21, 1995, 4 pages. .
Copy of letter from Paul G. Gagne for Schnader, Harrison, Segal
& Lewis to Brian Kaufman, Esquire, Re: Rinaldi, et al. v.
Integrated Seminars, Inc., et al., dated Feb. 15, 1995, 1 page.
.
Copy of letter from Lori A. Bateman of Quintessence Publishing Co.,
Inc. to Leonard I. Linkow, DDS, dated Feb. 8, 1995, 1 page. .
Declaration of Leonard I. Linkow executed Feb. 23, 1995 with
Exhibits A-N, Sample Implants and Pictures. .
Letters from Mark D. Friedman of core-Vent Bio-Engineering dated
Feb. 24, 1995 to Melvin C. Garner, Esq. of Darby & Darby. .
Osseointegrated Implants in the treatment of Edentulous Jaw P-I
Branemark B.O. Hansson, R. Adell U. Briene, J. Lindstrom, O. Hallen
and A. Ohman. .
T. Albrektsson, et al., Osseointegrated Titanium Implants, Acta
orthop. scand. 52, 155-170 (1981). .
Branemark, Osseointegration and Its Experimental Background,
Journal of Prosthetic Denistry, vol. 50-No. 3, pp. 399-410 (sep.
1983). .
Branemark et al., Osseointegrated Implants in the Treatment of the
Edentulous Jaw, p. 31 (1977). .
Adell, et al., A 15-Year Study of Osseointegrated in the Treatment
of the Endentulous Jaw, Int. J. Oral Surg., pp. 387-416 (1981).
.
Guernsey, Reconstructive Implant Surgery and Implant Prosthodontics
II, The Dental Clinics of North AMerica, vol. 30, No. 2 (Apr.
1986). .
Branemark et al., Osseointegrated Implants in the Treatment of the
Edentulous Jaw, (1977) pp. 31-33. .
Linkow, Theories and Techniques of Oral Implantology, vol. 1, C.V.
Mosby Co. (1970) pp. 1, 9, 147, 156, 157 and 167..
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Primary Examiner: O'Connor; Cary E.
Attorney, Agent or Firm: Darby & Darby
Parent Case Text
.Iadd.This is a continuation of application Ser. No. 07/771,398,
filed Oct. 2, 1991, now abandoned, which is a reissue application
of U.S. Pat. No. 4,932,868 issued Jun. 12, 1990.
.Iaddend..[.This.]. .Iadd.which .Iaddend.is a continuation of
application Ser. No. 025,942, filed Mar. 16, 1987, now U.S. Pat.
No. 4,842,518, issued June 27, 1989, which is a
continuation-in-part of Patent Application Ser. No. 904,381 filed
Sept. 4, 1986 and now .[.abandoned.]. .Iadd.U.S. Pat. No.
4,713,004.Iaddend..
Claims
What is claimed is:
1. An implant portion of an implant designed for supporting a
prosthetic structure comprising:
an implant body having threads over at least part of its exterior
surface and being adapted to be threaded into an opening in a bone
of a patient.Iadd., .Iaddend.which bone has been exposed by an
incision in the covering tissue; and
at least one channel formed such that it at least extends through
threads .[.on.]. .Iadd.of .Iaddend.the body for directing bone
chips toward a base portion of the opening in the bone, one edge of
the threads at one side of the channel being substantially at a
right angle to the circumferential direction of the threads
.Iadd.and shaped to form at least one cutting edge at one of the
threads.Iaddend., said .Iadd.at least .Iaddend.one .Iadd.cutting
.Iaddend.edge .[.being adapted.]. .Iadd.having a bone tapping and
scraping surface so as to come into contact with the bone
surrounding the opening upon insertion of the implant body into the
opening and while a major portion of the implant body is outside
the opening such that threading of the implant body further into
the opening causes the bone tapping and scraping surface to engage
the surrounding bone and .Iaddend.(i) to .[.promote self-tapping
of.]. .Iadd.self-tap .Iaddend.the threads .[.in.]. .Iadd.into
.Iaddend.the .Iadd.surrounding .Iaddend.bone, (ii) to shave off
pieces of bone during threading of the implant .[.portion.].
.Iadd.body .Iaddend.into .Iadd.the opening in .Iaddend.the bone,
and (iii) to direct the pieces of bone into the channel such that
the channel may direct pieces toward the base portion of the
opening.
2. An implant portion of an oral implant designed for supporting an
artificial tooth structure comprising:
a generally cylindrical implant body having a plurality of
circumferential projections extending over at least part of its
exterior surface and being adapted to be installed in an opening in
the bone of a patient by rotation thereof at least in part; and
at least one channel formed such that it extends generally
longitudinally through the projections of the body for directing
bone chips towards a base portion of the opening in the bone, one
edge of the projections at one side of said channel being
substantially at a right angle to the circumferential direction of
the implant body .Iadd.and shaped to form at least one cutting edge
at one of the projections.Iaddend., said .Iadd.at least
.Iaddend.one .Iadd.cutting .Iaddend.edge .[.being adapted.].
.Iadd.having a bone tapping and scraping surface so as to come into
contact with the bone surrounding the opening and while a major
portion of the implant body is outside the opening such that
rotation of the implant body further into the opening causes the
bone tapping and scraping surface to engage the surrounding bone
and .Iaddend.(i) to .[.promote self-tapping of.]. .Iadd.self-tap
.Iaddend.the projections .[.in.]. .Iadd.into .Iaddend.the
.Iadd.surrounding .Iaddend.bone during rotation of the implant
body, (ii) to shave off pieces of bone during rotation of the
implant body; and (iii) to direct the pieces of bone into the
channel such that the channel may direct pieces toward the base
portion of the opening.
3. An implant as claimed in claim 2 wherein the projections are
threaded and the implant portion is installed by threading it into
the opening in the bone. .Iadd.
4. The implant portion of claim 1, further including at least one
vent extending at least partially through the threaded part of the
body, said at least one vent being at least one of aligned with and
intersecting with the at least one channel..Iaddend..Iadd.5. The
implant portion of claim 4, wherein the at least one channel widens
toward the vent..Iaddend..Iadd.6. The implant portion of claim 1,
wherein the at least one channel terminates in an upper turn of the
threads remote from an apical portion of the
implant..Iaddend..Iadd.7. The implant portion of claim 2, wherein
the at least one channel terminates in an upper turn of the
circumferential projections remote from an apical portion of
the
implant..Iaddend..Iadd.8. The implant portion of claim 2, further
including at least one vent extending at least partially through
the projections of the cylindrical body, said at least one vent
being at least one of aligned with and intersecting with the at
least one channel..Iaddend..Iadd.9. The implant portion of claim 8,
wherein the at least one channel widens toward the
vent..Iaddend..Iadd.10. The implant portion of claim 2, wherein the
projections extend over a cylindrical part of the exterior surface
of the cylindrical implant body..Iaddend..Iadd.11. An implant
portion of an implant designed for supporting a prosthetic
structure comprising:
a generally cylindrical implant body having threads over at least
part of its exterior surface and being adapted to be installed in
an opening in the bone of a patient, which bone has been exposed by
an incision in the covering tissue; and
at least one channel formed such that it at least extends through
threads of the cylindrical implant body for directing bone chips
towards a base portion of the opening in the bone, one edge of the
threads at one side of said channel being substantially at a right
angle to the circumferential direction of the threads and shaped to
form at least one cutting edge at one of the threads, said at least
one cutting edge having a bone tapping and scraping surface so as
to come into contact with the bone surrounding the opening upon
insertion of the implant body into the opening and while a major
portion of the implant body is outside the opening such that
threading of the implant body further into the opening causes the
bone tapping and scraping surface to engage the surrounding bone
and (i) to self-tap the threads into the surrounding bone, (ii) to
shave off pieces of bone during threading of the implant body into
the opening in the bone, and (iii) to direct the pieces of bone
into the channel such that the channel may direct pieces toward the
base portion of the opening..Iaddend..Iadd.12. The implant portion
of claim 11, further including at least one vent extending at least
partially through the threaded part of the cylindrical body and
intersecting the at least one channel, the at least one channel
widening toward the vent..Iaddend..Iadd.13. The implant portion of
claim 12, wherein the at least one channel widens toward the
vent..Iaddend..Iadd.14. The implant portion of claim 11, wherein
the at least one channel terminates in an upper turn of the threads
remote from an apical portion of the
implant..Iaddend..Iadd.15. The implant portion claim 11, further
including at least one vent extending at least partially through
the threaded part of the cylindrical body, said at least one vent
being at least one of aligned with and intersecting with the at
least one channel..Iaddend..Iadd.16. The implant portion of claim
11, wherein the threads extend over a cylindrical part of the
exterior surface of the cylindrical implant body..Iaddend..Iadd.17.
An implant portion of an implant designed for supporting a
prosthetic structure comprising:
an implant body having threads over at least part of its exterior
surface and being adapted to be threaded into an opening in a bone
of a patient, which bone has been exposed by an incision in the
covering tissue; and
at least one channel formed such that it at least extends through
threads of the body for directing bone chips toward a base portion
of the opening in the bone, one edge of the threads at one side of
the channel being shaped to form at least one cutting edge at one
of the threads, said at least one cutting edge having a bone
tapping and scraping surface so as to come into contact with the
bone surrounding the opening upon insertion of the implant body
into the opening and while a major portion of the implant body is
outside the opening such that threading of the implant body further
into the opening causes the bone tapping and scraping surface to
engage the surrounding bone and (i) to self-tap the threads into
the surrounding bone, (ii) to shave off pieces of bone during
threading of the implant body into the opening in the bone, and
(iii) to direct the pieces of bone into the channel such that the
channel may direct pieces toward
the base portion of the opening..Iaddend..Iadd.18. The implant
portion of claim 17, further including at least one vent extending
at least partially through the threaded part of the body, said at
least one vent being at least one of aligned with and intersecting
with the at least one channel..Iaddend..Iadd.19. The implant
portion of claim 17, wherein the at least one channel terminates in
an upper turn of the threads remote from an apical portion of the
implant..Iaddend..Iadd.20. An implant portion of an oral implant
designed for supporting an artificial tooth structure
comprising:
a generally cylindrical implant body having a plurality of
circumferential projections extending over at least part of its
exterior surface and being adapted to be installed in an opening in
the bone of a patient by rotation thereof at least in part; and
at least one channel formed such that it extends generally
longitudinally through the projections of the body for directing
bone chips towards a base portion of the opening in the bone, one
edge of the projections at one side of said channel being shaped to
form at least one cutting edge at one of the projections, said at
least one cutting edge having a bone tapping and scraping surface
so as to come into contact with the bone surrounding the opening
and while a major portion of the implant body is outside the
opening such that rotation of the implant body further into the
opening causes the bone tapping and scraping surface to engage the
surrounding bone and (i) to self-tap the projections into the
surrounding bone during rotation of the implant body, (ii) to shave
off pieces of bone during rotation of the implant body; and (iii)
to direct the pieces of bone into the channel such that the channel
may direct pieces toward the base portion of the
opening..Iaddend..Iadd.21. The implant portion of claim 20, wherein
the at least one channel terminates in an upper turn of the
circumferential projections remote from an apical portion of the
implant..Iaddend..Iadd.22. The implant portion of claim 20, further
including a vent extending at least partially through the threaded
part of the body and wherein the at least one channel widens toward
the vent..Iaddend..Iadd.23. The implant portion claim 20, further
including at least one vent extending at least partially through
the projections of the cylindrical body, said at least one vent
being at least one of aligned with and intersecting with the at
least one channel..Iaddend..Iadd.24. The implant portion of claim
23, wherein the at least one channel widens toward the
vent..Iaddend..Iadd.25. An implant as claimed in claim 20, wherein
the projections are threaded and the implant portion is installed
by threading it into the opening in the bone..Iaddend..Iadd.26. The
implant portion of claim 20, wherein the projections extend over a
cylindrical part of the exterior surface of the cylindrical implant
body..Iaddend..Iadd.27. An implant portion of an implant designed
for supporting a prosthetic structure comprising:
a generally cylindrical implant body having threads over at least a
cylindrical part of its exterior surface and being adapted to be
installed in an opening in the bone of a patient, which bone has
been exposed by an incision in the covering tissue; and
at least one channel formed such that it at least extends through
threads of the cylindrical part of the cylindrical implant body for
directing bone chips towards a base portion of the opening in the
bone, one edge of the threads at one side of said channel at the
cylindrical part of the implant body being shaped to form at least
one cutting edge at one of the threads, said at least one cutting
edge having a bone tapping and scraping surface so as to come into
contact with the bone surrounding the opening upon insertion of the
implant body into the opening and while a major portion of the
implant body is outside the opening, such that threading of the
implant body further into the opening causes the bone tapping and
scraping surface to engage the surrounding bone and (i) to self-tap
the threads into the surrounding bone, (ii) to shave off pieces of
bone during threading of the implant body into the opening in the
bone, and (iii) to direct the pieces of bone into the channel such
that the channel may
direct pieces toward the base portion of the
opening..Iaddend..Iadd.28. The implant portion of claim 27, further
including at least one vent extending at least partially through
the threaded part of the cylindrical body and intersecting the at
least one channel, the at least one channel
widening toward the vent..Iaddend..Iadd.29. The implant portion of
claim 28, wherein the at least one channel widens toward the
vent..Iaddend..Iadd.30. The implant portion of claim 18, wherein
the at
least one channel widens toward the vent..Iaddend..Iadd.31. The
implant portion of claim 27, wherein the at least one channel
terminates in an upper turn of the threads remote from an apical
portion of the
implant..Iaddend..Iadd.32. An implant portion of an implant
designed for supporting a prosthetic structure comprising:
an implant body having threads over at least part of its exterior
surface and being adapted to be threaded into an opening in a bone
of a patient, which bone has been exposed by an incision in the
covering tissue; and
at least one channel formed such that it at least extends through
threads on the body for directing bone chips toward a base portion
of the opening in the bone, one tapping edge on the threads at one
side of the channel being substantially at a right angle to the
circumferential direction of the threads, said one edge acting (i)
to cause self-tapping of the threads in the surrounding bone, (ii)
to shave off pieces of bone during threading of the implant body
into the opening in the bone, and (iii) to direct the pieces of
bone into the channel such that the channel may direct pieces
toward the base portion of the opening..Iaddend..Iadd.33. An
implant portion of an oral implant designed for supporting an
artificial tooth structure comprising:
a generally cylindrical implant body having a plurality of
circumferential projections extending over at least part of its
exterior surface and being adapted to be installed in an opening in
the bone of a patient by rotation thereof at least in part; and
at least one channel formed such that it extends generally
longitudinally through the projections of the body for directing
bone chips towards a base portion of the opening in the bone, one
edge of the projections at one side of said channel being
substantially at a right angle to the circumferential direction of
the implant body, said one edge acting (i) to cause self-tapping of
the projections in the bone during rotation of the implant body,
(ii) to shave off pieces of bone during rotation of the implant
body; and (iii) to direct the pieces of bone into the channel such
that the channel may direct pieces toward the base portion of the
opening..Iaddend..Iadd.34. An implant as claimed in claim 33,
wherein the projections are threaded and the implant portion is
installed by threading
it into the opening in the bone..Iaddend..Iadd.35. An implant
portion of an oral implant designed for supporting an artificial
tooth structure comprising:
a generally cylindrical implant body having a plurality of
circumferential threads extending over at least part of its
exterior surface and being adapted to be installed in an opening in
the bone of a patient by threading thereof at least in part into
the opening in the bone; and
at least one channel formed such that it extends generally
longitudinally through the threads of the body for directing bone
chips towards a base portion of the opening in the bone, one edge
of the threads at one side of said channel being substantially at a
right angle to the circumferential direction of the implant body,
said one edge acting (i) to cause self-tapping of the threads in
the surrounding bone during threading of the implant body into the
opening in the bone, (ii) to shave off pieces of bone during
threading of the implant body into the opening in the bone; and
(iii) to direct the pieces of bone into the channel such that the
channel may direct pieces toward the base portion of the
opening..Iaddend.
Description
TECHNICAL FIELD
This invention relates to dental implants and, more particularly,
to submergible screw-type implants
BACKGROUND ART
Screw-type implants are well known in the art. U.S. Pat. No.
3,499,222 of L. I. Linkow et al. discloses screw-type implants
which may be buried in the alveolar ridge crest bone of a patient
in an edentulous region. The implant has a threaded lower portion
which may be screwed into an opening created in the bone after the
tissue has been displaced. A coronal portion protrudes above the
bone and is used to support an artificial dental appliance, e.g. an
artificial tooth or bridge.
In more recent year's submergible implants have been created in
which the threaded portions of the implants can be completely
embedded in the bone. They may then be covered with tissue and
allowed to remain in place while new bone grows around the implant
and through vent holes in it. Once it is firmly anchored in new
bone (3 to 6 months), the tissue is reopened and an upper post
portion is screwed into the implant portion and is used to mount
the artificial dental device.
It is advantageous when installing an implant portion in the
patent's bone, if the implant is self-tapping in a bore created in
the bone. This causes it to be anchored better. Also, it would be
advantageous if the bone chips created during a self-tapping
operation were deposited into the bore or opening because these
chips promote faster bone growth because of their autogenous
nature.
In order to align the artificial tooth or other dental devices with
the other teeth of the patient, it may be necessary to have the
post portion at an angle to the implant portion. This may be
accomplished by bending the post portion so that its head is at an
angle to the threaded shaft. This bending may be accomplished
before the post is threaded into the implant portion or afterward.
If the post is bent before attachment to the implant, the proper
alignment is difficult to achieve. If bent after attachment, there
is a danger that too much stress will be put on the implant portion
and it will loosen in the bone and fail. Also bending the post may
fatigue the metal of the post and cause breakage.
DISCLOSURE OF THE INVENTION
The present invention is directed to a dental implant which, in its
preferred form, is of the submergible screw type with a
longitudinal channel or slot through the threads so as to improve
their self-tapping ability. The implant also has an angled
swivelable connector to allow the post for supporting an artificial
dental appliance to be positioned in proper alignment with other
teeth in the patient's mouth without applying stress to the
implant.
In an illustrative embodiment of the invention, the implant portion
of the device includes a threaded region that contains a
longitudinal channel through a portion of the outer parts of the
threads. The channel is wider toward its bottom. One side of the
channel is at a right angle to the implant circumference so as to
create a cutting edge that assists in the formation of a
self-tapping capability for the implant when it is installed in a
bore or opening in the patient's bone. The other side of the
channel is at an oblique angle to the circumference.
The channel guides bone chips created during the threading of the
implant toward the base of the bore in the bone. By terminating the
channel below the uppermost threads, epithelial tissue is prevented
from growing down into the bone along the channel.
The post or abutment portion of the implant which supports an
artificial dental appliance may be a straight portion on to which
the appliance is threaded. However, in situations where it must be
at an angle to the implant portion the abutment may be a separate
piece from the implant portion and may be attached thereto at an
angle by means of a connection portion of the abutment. The
connection portion may be in the form of a rotatable beveled
collar, a ball and socket joint, or other suitable means that allow
the post to swivel about the axis of the implant portion and/or to
assume various angles with respect to that axis. Once in place,
means are provided for securing the abutment against further
movement with respect to the implant portion. As a result the
implant can assume a desired angle to assure proper alignment of
the artificial dental structure with the other teeth of the patient
along the occlusal plane.
In one version the abutment may include an elastic ring This ring
flexibly separates an upper portion and lower portion of the
abutment, much in the manner of a shock absorber. With this
arrangement some of the shock of mastication is buffered so that it
is not applied directly to the screw implant.
The present invention also contemplates a unique surgical method.
With this method an incision is made in the tissue covering the
alveolar ridge crest bone. This underlying bone is then exposed and
a bore is drilled into the bone at a depth sufficient to hold the
implant portion of the device. The bore is made slightly smaller in
diameter than the implant device and is at an angle which will
allow it to engage the major portion of the available bone. Then
the implant device is threaded into the remaining bone about the
bore utilizing its self-tapping threads and the self-tapping
feature of the channel along its length. It is typically buried at
a depth such that it is submerged below the upper surface in the
bone and is completely buried in the bone.
During the insertion procedure bone chips are removed from the
walls of the bore while forming the grooves in the bone which match
the threads in the implant. These bone chips drop along the channel
to the base of the bore and help to promote growth of new bone
which firmly anchors the implant in place.
Threading of the implant portion into place may be accomplished
with a hexagonal projection or recess located at the free end of
the implant portion. This hexagonal section is connected to a
wrench-type device to screw the implant into the bone.
Once secured in place a cover of minimal height may be attached to
the exposed surface of the implant portion by a screw passing
through the cover and threaded into an aperture in that surface.
The tissue may then be sutured over the implant cover. New bone is
allowed to grow and to anchor the cover and implant firmly in
place. Several weeks or months later, the tissue is opened again
and the cover is removed. A threaded abutment or post is then
attached to the threaded aperture in the end of the implant
portion. This abutment is used for supporting the artificial dental
appliance.
The angle at which the implant portion is located in the bone may
not be the most conductive to the proper alignment of the
artificial tooth or other dental devices with the remaining teeth
of the patient. As a result, the abutment includes an angled,
swivelable connection portion for attaching the abutment to the
implant portion. In one embodiment fixed angular devices which are
rotatable about the longitudinal axis of the implant are utilized,
and in another embodiment the part is continuously swivelable to
any desired angle. In either case, after the abutment or support
for the artificial tooth is at the proper angle, it is locked such
that it remains in that position. Finally, the tissue is closed
about the abutment an the artificial tooth or bridge support is
cemented or screwed to the abutment.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other features of the present invention will be
more readily apparent from the following detailed description and
drawings of illustrative embodiments of the invention, in
which:
FIG. 1 is a schematic cross section of the side of a patient's face
showing the alveolar ridge crest with a screw type implant
according to the present invention installed therein;
FIG. 2 is an enlarged view of an illustrative embodiment of the
implant portion of the device of FIG. 1 with an external hex
projection;
FIG. 3 is a top view of the implant portion of FIG. 2 showing the
external hex portion;
FIG. 4 is a cross-sectional view through the implant portion of
FIG. 2 along line 4--4 showing the cross-sectional shape of the
channel according to the present invention;
FIG. 5 is an implant portion of a screw-type implant according to
the present invention with an internal hex recess;
FIG. 6 is a illustrative embodiment of a completed screw-type
implant with an angularly positioned threaded shaft attached
thereto;
FIG. 7 is a cross-sectional view of a ball and socket connection
portion of an abutment according to the present invention;
FIG. 8 illustrates a modification of the ball and socket joint of
FIG. 7;
FIG. 9 illustrates a further modification of the ball and socket
joint of FIG. 7;
FIG. 10 is a ball and socket joint connection portion with a
stationary ball;
FIGS. 11A and 11B are cross-sectional views of a unitary inner
casing and a two-part inner casting, respectively;
FIG. 12 is a side view of a healing collar according to the present
invention;
FIGS. 13 and 14 are front and side sectional views of an artificial
tooth with an abutment according to FIG. 7;
FIG. 15 is a cross-sectional view of an embodiment of an abutment
with a shock-absorbing cushion; and
FIG. 16 is an alternative embodiment of the screw of the
shock-absorbing abutment of FIG. 15.
DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
The present invention contemplates at least a two part screw-type
dental implant, i.e, an implant portion 10 which is buried in the
bone of the patient and a post or abutment portion 20 which is
attached thereto and which supports an artificial tooth structure
30. As shown in FIG. 1, an implant screw portion 10 is located in a
bore in the aveolar crest 11 at an angle that causes it to be in
the center of the thickest portion of good available bone. The
abutment 20 is attached both to the implant portion 10 and the
artificial tooth 30, and is set so that the tooth is at an angle to
the implant which causes the tooth to be in proper alignment.
In FIGS. 2 and 3 the screw implant portion 10 of FIG. 2 is
illustrated in more detail. This implant portion 10 contains
threads 13 which extend over the middle region of the implant
portion. These threads may have a flat bottom and be angled up to
form a Christmas tree shape in cross section. The lower half of the
implant portion 10 contains a cavity 14 (shown in dotted line).
Also, spaced about the lower end of the implant are holes or vents
16, 16a and 16b, which penetrate from its exterior to the interior
cavity 14. The purpose of these vents is to allow new bone to grow
through and into the center cavity in order to firmly anchor the
implant in the patient's bone. The upper surface 17 of the implant
portion defines a threaded aperture 19 which is used to connect the
abutment 20 to the implant portion 10. The projecting structure 12
which forms surface 17 has a hexagonal shape as shown more clearly
in FIG. 3. This hexagonal shape allows a tool, e.g. a wrench, to be
used to rotate the implant portion so as to thread it into the
patient's bone.
According to the present invention a channel 18 is cut through the
threads 13 and possibly into the outer casing of the implant
portion 10. As depicted in dotted line in FIG. 3 and in
cross-section in FIG. 4, the channel 18 is one of three channels
18, 18a, 18b in a typical implant portion. These channels are made
to intersect the respective vents 16, 16a and 16b which are spaced
at angles of 120 about the circumference of the implant portion 10.
The channels do not extend completely toward the upper surface 12
in order to prevent tissue from growing down along the channel, and
to prevent the incursion of food and bacteria. It should be
particularly noted in FIG. 4 that the channels 18 have on edge
which is at about 90.degree. to the circumference of the implant,
i.e., .Iadd.bone tapping and scraping .Iaddend.surface 18', and
another more obliquely shaped edge, i.e. surface 18".
During installation of the implant, an incision is made in the gum
tissue of the patient and the underlying bone is exposed. Then a
drill or burr is used to make an opening or bore hole in the bone
which is slightly larger in diameter than the implant portion body
10, but which is not as wide as the threads 13. A wider counterbore
may be provided to accommodate a protection collar as explained
subsequently. Next the implant is inserted up to the first thread
in the opening in the bone. A tool, such as a wrench, is used to
engage the hex portion 12 and to rotate the implant. The threads 13
are made to be self-tapping so that the implant portion will begin
to screw down into the patient's bone. If necessary, a bone tap can
be used to create grooves in the hard upper cortical bone prior to
insertion of the implant portion. The right angle surface 18' of
the channel also has self-tapping properties so as to ease the
insertion of the implant, once it has reached the depth of the
channels 18. Further turning of the implant causes the right angle
surface 18' to scrape off bone as the implant is being threaded and
to push the resulting bone chips forward. This causes the bone
chips to fall through the channels 18 and into the area of the
vents 16 where they may penetrate into the interior cavity 14. To
facilitate this, the channels 18 are made wider towards the vents
16.
As a result of this structure, bone chips created during the
implant procedure tend to accumulate at the base of the implant in
the patient's bone. Because of the autogenous nature of these bone
chips they promote the growth of new bone in the area and speed the
formation of new bone around and through the implant such that it
is anchored in place more rapidly.
In FIG. 5 there is shown an implant portion 10 which is nearly
identical to that shown in FIG. 1. The principal difference is
that, rather than having a hexagonal projection useful for applying
torque to the implant, a hexagonal recess 12' is provided. In
addition, the threaded aperture 19' is made somewhat smaller and is
located at the base of hexagonal recess 12'. As explained
previously, the threaded aperture 19' is used for attaching the
implant portion of the device to the abutment portion One
embodiment of such an attachment is shown in FIG. 6.
In FIG. 6 the upper part of the implant portion 10 is shown partly
broken away and partly in section. It is shown partly broken away
to exhibit the interior cavity 14 and the threads 13. Towards the
upper part of the implant portion it is shown in cross section.
This implant portion is like that shown in FIG. 5 with a hexagonal
recess 12' for rotating it into position in the bone. As shown in
FIG. 6 the screw type implant portion 10 is connected to an
abutment portion 20 that includes a transitional collar 21, an
angled threaded shaft 24, and a tooth support cylinder 31. The
threaded shaft 24 has its lower end screwed into threaded aperture
19' in the implant portion 10. The upper end of the threaded shaft,
which is set at an angle to the lower end, is received within a
threaded aperture 35 in tooth support cylinder 31. This cylinder 31
contains a recessed portion 32 which may be utilized in fixing on
to the cylinder via cement or some other convenient and well known
method, a porcelain, plastic, or other dental tooth-colored
veneering material in the form of an artificial tooth.
The transitional collar 21 is located between the upper end of the
implant portion 10 and the cylinder 31. This collar has an angled
upper surface 25 and a perpendicular lower surface 23. The angle of
the upper surface is made to equal the angle of the upper part of
the angled shaft 24. While collar 21 surrounds threaded shaft 24,
it does not engage its threads.
During an installation procedure the implant portion 10 is located
in the patient's bone as previously described. The gingival tissues
can then be replaced over the implant portion and several weeks or
months allowed to pass while new bone grows around and through the
implant portion. However, alternatively the artificial tooth can be
connected to the implant immediately. Whichever manner is chosen,
the attachment is accomplished by selecting an angled shaft and
transition collar which have an angle which will cause the
artificial tooth to be correctly aligned with the other teeth of
the patient. Therefore the dentist or oral surgeon must be provided
with a variety of such shafts and collars which are at standard
angles. Also during the insertion procedure the surgeon must
appropriately angle the opening in the bone so it penetrates a
reasonably thick area of good bone. This may require that the
opening in the bone be drilled at an angle in order to avoid
penetrating a nearby sinus cavity, passing completely through the
bone, or contacting a nerve bundle. However, in selecting the angle
at which the implant is buried, care must be taken to make sure
that this angle will accommodate one of the standard angles
available with the threaded shafts and collars, e.g. 10, 20 or 30
degrees, so as to result in alignment between the new artificial
tooth and the remaining teeth of the patient.
Once the threaded shaft 24 is engaged with the implant portion 10,
the collar 21 is slipped over the free end of the shaft. Then the
shaft is rotated so that it is firmly secured in the implant
portion and is extending in the proper direction. With the collar
in place over this shaft, the cylinder portion 31 is threaded over
the open or free end of the shaft until it makes tight contact with
the upper surface of the collar and begins to squeeze the collar
between the cylinder and implant portions. Notches and recesses 22
and 27 are provided in the mating surfaces such that, once the
parts are screwed together, these notches and recesses engage each
other and prevent unintentional unscrewing of the portions of the
implant. With this firm attachment completed, the artificial tooth
can then be attached over the abutment cylinder 31.
In FIG. 6 the level the patient's bone is shown as dotted line 70.
Since the implant portion is submerged in the bone, the line 70
intersects the lower portion of the transitional collar 20. The gum
tissue line 72 is towards the upper portion of the transitional
collar. As a result the collar acts a barrier to prevent the
encroachment of bacteria and food into the interior portion of the
collar and the hex recess of the implant portion.
With the embodiment of FIG. 6 fixed angles are provided to the
dentist and he must work with the standard angles and the angle
which he creates for the bore in the patient's bone, in order to
assure proper alignment of the teeth. In some patients who have had
serious bone disease, the amount of available good bone is limited
and the dentist has only a limited amount of freedom in selecting
the angle at which the bore for the implant is made. Also with the
embodiment of FIG. 6 it is necessary for a dentist to keep a stock
of various angled shafts and collars. The difficulty presented by
the type of implant in FIG. 6 is overcome by the implant shown in
FIG. 7.
In FIG. 7 the angled shaft and transition collar are replaced with
a ball and socket joint which allows for the setting of the angled
relationship between the implant portion and the abutment portion
at any selected angle within the range of motion of the ball and
socket joint, e.g. up to 30-40 degrees. In FIG. 7 the threaded
cavity 19 receives the threaded shaft of a lower or inner abutment
casing 42. This casing has a generally Y-shape with the lower
portion being the shaft that extends into and engage the threads of
cavity 19. The upper portion of casing 42 has a hemispherical
surface 45 such that it can receive a ball 46. An upper or outer
casing 44 screws onto outer threads of the inner casing 42 such
that ball 46 is wrapped within the abutment casing, but is free to
rotate therein so as to create a ball and socket joint.
A relatively large set screw 48 penetrates the ball completely.
This set screw 48 has an internal threaded cavity 55 which passes
through an upper hexagonal projection 56. Once the implant portion
10 has been located in the bone at the optimal angle, the ball 46
is rotated such that the center axis of the set screw is at the
proper angle for mounting of an artificial tooth in line with other
teeth in the patient's mouth. Then the hexagonal portion 56 is
rotated with a wrench or other tool so the set screw comes into
extreme frictional contact with the hemispherical surface 45 of
inner casing 42. This prevents further rotation of the ball and the
set screw.
The artificial tooth structure in the embodiment of FIG. 7 has an
interior cylinder 50, about which the porcelain, plastic or other
dental material is formed to create the artificial tooth structure.
This cylinder 50 with the artificial tooth structure mounted
thereon, is placed on top of the hexagonal projection 56 and is
then attached thereto by means of a screw 52 which passes through
the cylinder 50 and into the threaded aperture 55 in set screw
48.
The bone line 70 is shown in FIG. 7 as being approximately mid-way
through the lower abutment casing 42, while the gum line 72 is just
below the upper edge of the outer or upper casing 44. Thus, the
bone does not interfere with the setting of the proper angle for
the abutment and the tissue is not likely to contact moveable
adjustment parts.
The arrangement of FIG. 8 is a modification of that shown in FIG.
7. In this arrangement the set screw 48, which has a threaded
recess 55 at its end in FIG. 7, is replaced with a set screw 49
that has a further screw thread 59 on the opposite side of the hex
projection 56. This additional screw thread is used to mount an
artificial tooth support cylinder 53 which has an interior threaded
cavity. However, this device is essentially located and fixed in
position in the same manner as the implant of FIG. 7. One
difference with this implant of FIG. 8 is that the artificial tooth
support cylinder 53 may extend down to and in contact with the
outer casing 44. This is done above the gum tissue line 72 as shown
in the figure. Because of the contact between the cylinder and the
casing 44, food and bacteria are prevented from entering between
these two parts and the likelihood of infection is reduced.
However, this arrangement allows for somewhat less range of angular
adjustment. In particular the arrangement of FIG. 7 is capable of
an angular adjustment range of approximately 371/2.degree., while
that of FIG. 8 is limited to about 30.degree..
As a further alternative, the set screw 48, rather than having a
projecting threaded portion located above the hexagonal adjustment
nut 56, may have a projecting cylinder which is internally threaded
(not shown). Thus either a male or female connection of this type
may be used without difficulty.
In order to get increased angular adjustment, an arrangement such
as that shown in FIG. 9 may be used. The abutment arrangement of
FIG. 9 is essentially the same as that of FIG. 7; however, the ball
and socket joint are made smaller and the ball sits higher in the
socket joint. Further, the set screw 54 of FIG. 9 is made to have a
beveled surface 57 such that a greater angular rotation may be made
before it contacts the upper part of the outer casing 44. With this
arrangement nearly 45 degrees of angular adjustment can be
achieved.
The abutment cylinder 50 has a recess 51 to receive the outer end
of the set screw 54. This allows for greater stability when it is
attached to the set screw by means of attachment screw 52. The
cylinder 50 is also angled in the same manner as the surface 57 of
the set screw 54 so that it does not bind against the upper
abutment casing 44 and limit angular rotation.
In FIG. 7-9 the ball rotates with the set screw during angular
adjustment. However, as an alternative, the ball may remain
stationery and the abutment casing may rotate as shown in FIG. 10.
In FIG. 10 a threaded ball joint 60 has a projecting threaded shaft
61 which is received in threaded recess 19 of the implant portion
10. Various size protection washers or collars 65 can be located
about the finial part 67, which connects the ball to the threaded
shaft, in order to cover the upper surface of whatever implant
portion is used, thereby preventing bacteria and food from entering
the bore. The opening in the bone can be countersunk as indicated
by dotted line 70 so the collar can extend out beyond the implant
portion upper surface, and bone can grow over part of the upper
surface of the collar.
A two-part casing 62, 64 is mounted on the ball 60. The casing
includes outer casing portion 62, which secures the remote end of
the ball, and an inner casing 64, which provides the main
hemispherical surface against which the outer casing holds the ball
in a rotatable manner. These two casing parts can be threaded
together or attached to each other in any convenient manner. Their
attachment, however, is such that the casing may rotate freely on
the ball.
At the opposite end of ball 60 from the screw threads is a
hexagonal recess 63, which is the means by which this threaded ball
joint is screwed into the threaded recess 19 of the implant
portion. In this arrangement the gum line 72 is shown about 1/3 up
from the base of the ball joint, but below the lower extension of
casing 62.
A hexagonal projection 66 is provided on the inner casing 64. This
projection can be used to rotate the inner casing 64 so that the
ball is squeezed between it and the outer casing 62 so that
swiveling can be prevented when the arrangement is at the proper
angle. A conventional cylinder 50 for a dental prosthesis is
attached to the inner casing 64 by means of a screw 52. This screw
52 penetrates a threaded aperture in the inner casing.
An enlarged view of the inner casing 64 is shown in FIG. 11A. The
lower peripherial extension 64, of this casing forms a wedge that
projects between the ball 60 and the outer casing 62 as shown in
FIG. 10. When the inner casing 64 is screwed down onto ball 60, the
extension 64, acts to lock the abutment on the ball and prevents
further rotation. In part this locking is maintained due to the
fact that the diameter of the extension 64' is slightly less that
the distance across the ball at its location. As a result there is
an outward flaring of the extension as shown by the arrows in FIG.
11A, which prevents the unthreading of inner casing 64.
Instead of a one piece casing as shown in FIG. 11A, the inner
casing may be in two parts as shown in FIG. 11B, where the
extension 64' is part of a locking ring or washer 64". With this
arrangement the ball is surrounded by the ring 64" and the casing
64. As the casing is threaded into contact with the ball it forces
the ring to wedge between the ball 60 and the outer casing to
frictionally hold the ball. The outward flaring of the extension at
the end of this compression process tends to prevent the
unthreading of the inner casing, which prevents the abutment from
becoming loose.
Installation of submergible implants is generally a two stage
procedure. During the first stage the implant portion is buried in
the bone and the tissue is restored in place over it. Time is
allowed to pass while new bone grows about, and often over, the
implant. The tissue is then reopened at the start of the second
stage. If bone has grown over the submerged implant, it must be
removed by a burr before the abutment can be installed. If the bone
grows into the threaded aperture for the abutment, however, removal
of this bone may be very difficult. Consequently, it is
conventional to install a thread cap having a low height into the
aperture during the first stage. However, bone also grows over this
cap and it must be removed in order to replace the cap with the
abutment. Removal of such bone may cause some loosening of the
implant portion.
With the present invention, the collar 65 is used with a screw 68
as a temporary cap as shown in FIG. 12. Even if bone grows up over
the edges of the collar 65, there is no need to remove it because
it becomes part of the permanent abutment. In particular cover
screw 68 is removed during the second stage operation, which may
require the removal of a small amount of bone that has growth over
the screw. Then the cover screw 68 is replaced with threaded shaft
of abutment ball 60 which has the abutment casings 62, 64 already
installed. Thus the collar 65 which is anchored in bone, need not
be freed from the bone as in prior art caps, but becomes part of
the final abutment structure.
FIGS. 13 and 14 show front and side sectional views of an incisor
of a patient which is supported by an implant according to the
present invention. As can be seen, particularly from FIG. 14, the
patient's upper front jaw bone has only a thin amount of good bone
11 and this bone is at an angle to the regular alignment of the
other incisors in the patient's mouth. Utilizing the present
invention, implant portion 10 is located in the center of the main
portion of this bone. After this implant portion 10 is firmly
anchored in good bone, either immediately after its insertion or
after several weeks or months have been allowed to pass, the
abutment portion is installed. The abutment portion is a ball and
socket joint like that in FIG. 7 having a set screw 48 which locks
the ball 46 at the proper angle. The cylinder 50 of the artificial
tooth support is then attached to the set screw via an attachment
screw 52. As shown in cross section in FIG. 14, cast metal 58
surrounds cylinder 50 and a porcelain or plastic dental material 70
forms the tooth structure about the metal.
FIG. 15 illustrates a cross-sectional view of an abutment with
shock-absorbing capabilities. This abutment may be adapted for use
with any of the previously discussed implants and angular
adjustment devices.
The abutment of FIG. 15 has a cylinder portion 70, upon which the
artificial tooth is mounted. In addition it has a collar 72. The
cylinder and collar are connected by a screw 74. Screw 74 also acts
to connect the cylinder and collar 70,72 to the rest of the
abutment in much the same way as screw 52 connects cylinder 50 to
the rest of the implants in FIGS. 7, 9 and 10.
A flexible buna rubber washer 76, such as that used for over
dentures, is located between and separates the cylinder 70 and
collar 72 so that the cylinder 70 may move with respect to the
collar 72. Typically, the artificial tooth will be mounted only on
the cylinder 70. As a result, some of the forces applied to the
artificial tooth during chewing or biting are absorbed by the
flexible washer 76 and are not transmitted to the collar 72 and the
rest of the implant.
In order to make it easy to install the washer 76, the cylinder and
collar parts are formed such that they define an oval recess which
seats the washer. The head 75 of the screw 74 and a peripheral
flare 73 on the screw tend to keep the washer within the oval
recess.
During installation the washer is assembled between the cylinder 70
and collar 72. Then the screw 74 is pushed down through the opening
in the cylinder part. The flare 73 compresses the washer 76
slightly as it passes through the washer. Then the screw 74 is
passed through collar 72 and threaded into the rest of the implant.
At some point, the flare 73 is drawn against the opening in collar
72. However, the threading operation is continued in order to wedge
the flared part of screw 74 into collar 72. This acts to keep screw
74 from unthreading after the artificial tooth is put into use.
FIG. 16 shows an alternative version of the screw 74 of FIG. 15. In
this alternative, the flared part 73 has a triangular
cross-sectional shape. Once this screw has been pushed through the
washer 76, it cannot be withdrawn. Thus, it is necessary to cut the
washer to remove it.
Besides being used to mount a single tooth, the implants according
to the present invention can be used as supports for a permanent
bridge or a removable bridge. In the case of a removable bridge the
abutment cylinder is in the form of small copings which can be
spaced throughout the edentulous span of a patient. These copings
support a bar onto which the bridge structure may be screwed or
clipped.
While the invention has been particularly shown and described with
reference to preferred embodiments thereof, it will be understood
by those skilled in the art that various changes in form and
details may be made thereon without departing from the spirit and
scope of the invention.
* * * * *