U.S. patent application number 09/832491 was filed with the patent office on 2001-08-09 for guided tissue regeneration plate for use in a process for growing jaw bone in anticipation of performing dental implants.
Invention is credited to Robinson, Dane O..
Application Number | 20010012607 09/832491 |
Document ID | / |
Family ID | 24442696 |
Filed Date | 2001-08-09 |
United States Patent
Application |
20010012607 |
Kind Code |
A1 |
Robinson, Dane O. |
August 9, 2001 |
Guided tissue regeneration plate for use in a process for growing
jaw bone in anticipation of performing dental implants
Abstract
A method of growing jaw bone and the related guided-tissue
regeneration plate support and fixation system employed in the
method where an isolated and protected space free from tissue
impingement, occlusal loading, chewing forces or muscular pressure
is created between the periosteum and the jaw bone. This space is
created by first placing either a dental implant or a guided-tissue
regeneration plate support and fixation system tenting-type support
screw into the jaw bone. The plate portion of the guided-tissue
regeneration plate support and fixation system, preferably made out
of titanium, is a two-piece structure including a first support
plate component having a peripheral region and a generally open
central portion and a fine mesh screen juxtaposed over the central
portion of the support plate and fixed to the peripheral region
thereof. Alternatively, a titanium blank can be controllably etched
to obtain reduced thickness central regions which, along with the
original thickness regions, are methodically pierced to obtain
numerous apertures to achieve the desired porosity for the central
regions and the desired strength and pliability of the peripheral
regions. The guided-tissue regeneration plate is either
snapped-down onto the head of the support screw or onto a
specialized and modified healing screw of a dental implant which
has a receiver cap or is screwed directly into a dental implant.
The plate is then bent and molded into the proper shape to provide
the protected space.
Inventors: |
Robinson, Dane O.;
(Scottsdale, AZ) |
Correspondence
Address: |
SQUIRE, SANDERS & DEMPSEY L.L.P.
Two Renaissance Square
Suite 2700
40 North Central Avenue
Phoenix
AZ
85004-4498
US
|
Family ID: |
24442696 |
Appl. No.: |
09/832491 |
Filed: |
April 10, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09832491 |
Apr 10, 2001 |
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09196915 |
Nov 20, 1998 |
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6238214 |
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09196915 |
Nov 20, 1998 |
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08609870 |
Mar 1, 1996 |
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5839899 |
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Current U.S.
Class: |
433/215 ;
433/173; 623/17.17 |
Current CPC
Class: |
A61C 8/0006 20130101;
Y10S 623/919 20130101 |
Class at
Publication: |
433/215 ;
433/173; 623/17.17 |
International
Class: |
A61C 005/00; A61C
008/00; A61F 002/02 |
Claims
What is claimed is:
1. In apparatus for use in a method of growing bone in order to
increase the volume of the bony ridge of the maxilla or mandible by
creating a protected and supported space between the underside of
the gum tissue and the jaw bone which is protected from outside
chewing forces, muscular or tissue pressure, or any other premature
loading by utilizing a guided-tissue regeneration plate support and
fixation system, which method comprises: A) fixing a support medium
to the jaw bone, said support medium being configured to receive
and support a guided-tissue regeneration plate; B) juxtaposing a
guided-tissue regeneration plate with respect to the jaw bone in a
tent-like manner to create a protected space by affixing said
guided-tissue regeneration plate to and suspending it from said
support medium, which said guided-tissue regeneration plate is
pliable and moldable, but keeps its shape after being molded, said
guided-tissue regeneration plate being further characterized in
that it is fabricated from a bio-compatible material; and C)
waiting for bone to grow in the resulting protected space; the
improvement in which: D) said guided-tissue regeneration plate
comprises first and second integrated components including: 1) a
first component comprising a support plate having a peripheral
region and a generally open central portion; and 2) a fine mesh
screen juxtaposed over said central portion of said support plate
and fixed to said peripheral region thereof.
2. The apparatus of claim 1 in which said support plate and said
fine mesh screen are each made of a bio-compatible material
selected from the group including titanium, chromium cobalt alloy
and Teflon-coated surgical steel and in which said peripheral
region of said support plate is perforated.
3. The apparatus of claim 1 in which said guided-tissue
regeneration plate is coated with a resorptive, bio-compatible
material for the purpose of creating a temporary guided-tissue
regeneration plate barrier to prevent migration of epithelial cells
across its surface, yet allow blood supply and/or nutrients to pass
through the resorptive barrier.
4. The apparatus of claim 2 in which said guided-tissue
regeneration plate is coated with a resorptive, bio-compatible
material for the purpose of creating a temporary guided-tissue
regeneration plate barrier to prevent migration of epithelial cells
across its surface, yet allow blood supply and/or nutrients to pass
through the resorptive barrier.
5. The apparatus of claim 1 in which: A) the thickness of said
peripheral region of said support plate falls within the range of
0.008-0.025 of an inch; and B) said fine mesh screen comprises a
weave of wire in which: 1) the diameter said wire employed falls
within the range of 0.002-0.006 of an inch; and 2) the weave of
said wire falls within the range of 10.times.10 wires per inch to
200.times.200 wires per inch.
6. The apparatus of claim 2 in which: A) the thickness of said
peripheral region of said support plate falls within the range of
0.008-0.025 of an inch; and B) said fine mesh screen comprises a
weave of wire in which: 1) the diameter said wire employed falls
within the range of 0.002-0.006 of an inch; and 2) the weave of
said wire falls within the range of 10.times.10 wires per inch to
200.times.200 wires per inch.
7. The apparatus of claim 3 in which: A) the thickness of said
peripheral region of said support plate falls within the range of
0.008-0.025 of an inch; and B) said fine mesh screen comprises a
weave of wire in which: 1) the diameter said wire employed falls
within the range of 0.002-0.006 of an inch; and 2) the weave of
said wire falls within the range of 10.times.10 wires per inch to
75.times.75 wires per inch.
8. The apparatus of claim 4 in which: A) the thickness of said
peripheral region of said support plate falls within the range of
0.008-0.025 of an inch; and B) said fine mesh screen comprises a
weave of wire in which: 1) the diameter said wire employed falls
within the range of 0.002-0.006 of an inch; and 2) the weave of
said wire falls within the range of 10.times.10 wires per inch to
200.times.200 wires per inch.
9. The apparatus of claim 1 in which integral struts extend from
said peripheral region of said support plate into said generally
open central portion thereof to provide support for said fine mesh
screen.
10. The apparatus of claim 2 in which integral struts extend from
said peripheral region of said support plate into said generally
open central portion thereof to provide support for said fine mesh
screen.
11. The apparatus of claim 5 in which integral struts extend from
said peripheral region of said support plate into said generally
open central portion thereof to provide support for said fine mesh
screen.
12. The apparatus of claim 6 in which integral struts extend from
said peripheral region of said support plate into said generally
open central portion thereof to provide support for said fine mesh
screen.
13. The apparatus of claim 1 in which at least a plurality of said
integral struts join a circular central support having an aperture
therethrough for coupling with said support medium.
14. The apparatus of claim 2 in which at least a plurality of said
integral struts join a circular central support having an aperture
therethrough for coupling with said support medium.
15. The apparatus of claim 5 in which at least a plurality of said
integral struts join a circular central support having an aperture
therethrough for coupling with said support medium.
16. The apparatus of claim 6 in which at least a plurality of said
integral struts join a circular central support having an aperture
therethrough for coupling with said support medium.
17. The apparatus of claim 9 in which at least a plurality of said
integral struts join a circular central support having an aperture
therethrough for coupling with said support medium.
18. The apparatus of claim 10 in which at least a plurality of said
integral struts join a circular central support having an aperture
therethrough for coupling with said support medium.
19. The apparatus of claim 11 in which at least a plurality of said
integral struts join a circular central support having an aperture
therethrough for coupling with said support medium.
20. The apparatus of claim 12 in which at least a plurality of said
integral struts join a circular central support having an aperture
therethrough for coupling with said support medium.
21. In apparatus for use in a method of growing bone in order to
increase the volume of the bony ridge of the maxilla or mandible by
creating a protected and supported space between the underside of
the gum tissue and the jaw bone which is protected from outside
chewing forces, muscular or tissue pressure, or any other premature
loading by utilizing a guided-tissue regeneration plate support and
fixation system, which method comprises: A) fixing a support medium
to the jaw bone, said support medium being configured to receive
and support a guided-tissue regeneration plate; B) juxtaposing a
guided-tissue regeneration plate with respect to the jaw bone in a
tent-like manner to create a protected space by affixing said
guided-tissue regeneration plate to and suspending it from said
support medium, which said guided-tissue regeneration plate is
pliable and moldable, but keeps its shape after being molded, said
guided-tissue regeneration plate being further characterized in
that it is fabricated from a bio-compatible material; and C)
waiting for bone to grow in the resulting protected space; the
improvement in which: D) said guided-tissue regeneration plate
comprises first and second regions of a monolithic structure: 1)
said first region comprising a peripheral area having a first
thickness; and 2) said second region comprising a central area
having a thickness which is less than that of said peripheral
region, said central area being perforated with a plurality of
apertures.
22. The apparatus of claim 21 in which said monolithic structure is
made of a bio-compatible material selected from the group including
titanium, chromium cobalt alloy and Teflon-coated surgical steel
and in which said peripheral region of said support plate is
perforated.
23. The apparatus of claim 21 in which said guided-tissue
regeneration plate is coated with a resorptive, bio-compatible
material for the purpose of creating a temporary guided-tissue
regeneration plate barrier to prevent migration of epithelial cells
across its surface, yet allow blood supply and/or nutrients to pass
through the resorptive barrier.
24. The apparatus of claim 21 in which said guided-tissue
regeneration plate is coated with a resorptive, bio-compatible
material for the purpose of creating a temporary guided-tissue
regeneration plate barrier to prevent migration of epithelial cells
across its surface, yet allow blood supply and/or nutrients to pass
through the resorptive barrier.
25. The apparatus of claim 21 in which: A) the thickness of said
peripheral area of said guided-tissue regeneration plate falls
within the range of 0.008-0.025 of an inch; and B) the thickness of
said central area of said guided-tissue regeneration plate falls
within the range of 0.002-0.006 of an inch.
26. The apparatus of claim 22 in which: A) the thickness of said
peripheral area of said guided-tissue regeneration plate falls
within the range of 0.008-0.025 of an inch; and B) the thickness of
said central area of said guided-tissue regeneration plate falls
within the range of 0.002-0.006 of an inch.
27. The apparatus of claim 21 in which integral struts extend from
said peripheral area of said guided-tissue regeneration plate into
said central area to provide support for said central area.
28. The apparatus of claim 22 in which integral struts extend from
said peripheral area of said guided-tissue regeneration plate into
said central area to provide support for said central area.
29. The apparatus of claim 25 in which integral struts extend from
said peripheral area of said guided-tissue regeneration plate into
said central area to provide support for said central area.
30. The apparatus of claim 26 in which integral struts extend from
said peripheral area of said guided-tissue regeneration plate into
said central area to provide support for said central area.
31. The apparatus of claim 21 in which at least a plurality of said
integral struts join a circular central support having an aperture
therethrough for coupling with said support medium.
32. The apparatus of claim 22 in which at least a plurality of said
integral struts join a circular central support having an aperture
therethrough for coupling with said support medium.
33. The apparatus of claim 25 in which at least a plurality of said
integral struts join a circular central support having an aperture
therethrough for coupling with said support medium.
34. The apparatus of claim 26 in which at least a plurality of said
integral struts join a circular central support having an aperture
therethrough for coupling with said support medium.
35. The apparatus of claim 27 in which at least a plurality of said
integral struts join a circular central support having an aperture
therethrough for coupling with said support medium.
36. The apparatus of claim 28 in which at least a plurality of said
integral struts join a circular central support having an aperture
therethrough for coupling with said support medium.
37. The apparatus of claim 29 in which at least a plurality of said
integral struts join a circular central support having an aperture
therethrough for coupling with said support medium.
38. The apparatus of claim 30 in which at least a plurality of said
integral struts join a circular central support having an aperture
therethrough for coupling with said support medium.
39. The apparatus of claim 21 in which said guided-tissue
regeneration plate is fabricated by the steps of: A) overlaying, on
a first surface of a monolithic plate, a mask conforming to the
shape of said peripheral area such that only an area conforming to
the shape of the central area is exposed; B) etching the first
surface of the monolithic plate in the exposed area to diminish the
thickness of the monolithic plate in the exposed area; and C)
perforating the central area with a plurality of apertures.
40. The apparatus of claim 39 in which the monolithic plate is a
titanium plate.
41. In apparatus for use in a method of growing bone in order to
increase the volume of the bony ridge of the maxilla or mandible by
creating a protected and supported space between the underside of
the gum tissue and the jaw bone which is protected from outside
chewing forces, muscular or tissue pressure, or any other premature
loading by utilizing a guided-tissue regeneration plate support and
fixation system, which method comprises: A) juxtaposing a
guided-tissue regeneration plate with respect to the jaw bone in a
tent-like manner to create a protected space, which said
guided-tissue regeneration plate is pliable and moldable, but keeps
its shape after being molded, said guided-tissue regeneration plate
being further characterized in that it is fabricated from a
bio-compatible material; and B) waiting for bone to grow in the
resulting protected space; the improvement in which: C) at least a
first region of the surface of said guided-tissue regeneration
plate is roughened to decrease the surface tension thereof.
42. The apparatus of claim 41 in which the entire surface of said
guided-tissue regeneration plate is roughened to decrease the
surface tension thereof.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This is a Continuation-in-Part of U.S. patent application
Ser. No. 08/609,870, filed Mar. 1, 1996, by Dane Q. Robinson and
entitled METHOD AND APPARATUS FOR GROWING JAW BONE UTILIZING A
GUIDED-TISSUE REGENERATION PLATE SUPPORT AND FIXATION SYSTEM, now
U.S. Pat. No. 5,839,899.
FIELD OF THE INVENTION
[0002] This invention relates to the art of dentistry and, more
particularly, to a devices which relate to the surgical placement
of endosseous dental implants in the maxillary or mandibular jaw
bone. Still more specifically, this invention relates to the
growing of jaw bone in order to obtain adequate volume of osseous
structure by using a thin titanium bone plate/screen which is mated
to an underlying support bone screw or to a dental implant.
BACKGROUND OF THE INVENTION
[0003] The successful placement of endosseous dental implants has
been well documented for over 30 years; however, the success of
these endosseous dental implants has been limited by the quality
and quantity of existing bone a given patient would present with.
Due to the destructive nature of dentures to the underlying jaw
bone as well as to the fact that bone that is not internally
stimulated by tooth roots will atrophy, the amount of bone in many
people is very limited for the placement of dental implants,
especially for those who have been missing teeth for an extended
period of time.
[0004] Bone grafting has become an essential element for the
successful treatment of those who do not have enough bone for
dental implants. As viable methods, blocks of hip bone have been
affixed to the jaw, and freeze-dried demineralized bone protein has
been used as a stimulant to cause the patient's bone cells to
become active and lay down new bone onto the existing bone areas
and into the new bone graft areas. Through experience and research,
it has become evident that, for bone grafting to be successful, it
must be given an isolated space to grow, protected from muscular
pressure, tissue impingement and chewing forces. In order to create
this space, many approaches have been proposed. For example, both
Syers (U.S. Pat. No. 5,297,563) and Magnusson et al (U.S. Pat. No.
4,961,707) teach the use of a fabric-like membrane which is used
over a bony defect. Although this barrier creates an isolated space
from the invasion of epithelial cells into the bony defect or bone
graft area, it does not create a protected space from chewing
forces or tissue pressure.
[0005] Morgan (U.S. Pat. No. 5,380,328) teaches the use of a
composite perforated titanium mesh layered with
polytetrafluoraethylene (PTFE or Teflon.RTM.) fibers. Even though
this approach would be feasible for creating a protected space in
order to grow bone, it has some severe limitations. This material
requires the placement of peripheral bone screws into the edges of
the meshed piece in order to create a direct fixation of the
titanium mesh to the jaw bone and then bowing-up or tenting-up the
center area in order to create the protected space. Often, it would
not be feasible to place the peripheral bone screws in the
peripheral areas for fear of damage to the inferior alveolar nerves
or sinus penetration or damage to nearby tooth roots. The
protrusion of these screws above the mesh is also of concern as
potentially causing a tissue irritation complication with this
given procedure.
[0006] Furthermore, the difficulty of forming the exact amount of
tenting desired with this material is inherently very difficult to
control. Additionally, the removal of this material is complicated
by the need to surgically dissect much deeper to locate the
peripheral screws. This technique would also be expensive and time
consuming to emplace due to the need for multiple screws to secure
a single mesh.
[0007] On the other hand, as will become more apparent below, the
guided-tissue regeneration plate support and fixation system
contemplated in accordance with the subject invention obtains the
ability to place a single screw in the center of the bone graft
area, thereby facilitating the selection of a screw height that
allows for an exact amount of tenting, thus giving the support
where it is needed most. Placement and removal of this device is
greatly simplified due to the fact that peripheral screws are not
required (although such can be used). The head of the screw ends up
being mostly under the plate, thus preventing any concern about
screw-head irritation or protrusion. Furthermore, concern about
damage to neighboring peripheral structures is eliminated. In
general, a much more simplified and cost effective method,
apparatus and result are achieved.
[0008] Experience with and further development of the guided-tissue
regeneration plate support and fixation system has resulted in an
important advance which enhances its effectiveness in practice. It
has been found that the use of a fine mesh screen spanning open
areas of a guided-tissue regeneration support plate results in a
faster and more complete bone regeneration of the underlying bony
ridge and faster and more healthy growth of the overlying
periosteum. The fine mesh screen can be fabricated from any
suitable material, resorptive or non-resorptive, and an especially
suitable material, especially when a titanium guided-tissue support
plate is employed, is fine mesh screen titanium fixed to the
support plate by welding, particularly spot or laser welding, by an
adhesive or by sintering the two-piece assembly. Alternatively, a
functional equivalent to a fine mesh screen region can be obtained
by substantially reducing the thickness of predetermined central
areas of an imperforate titanium (for example) plate and then
perforating the reduced thickness regions with finely spaced
apertures.
OBJECTS OF THE INVENTION
[0009] It is therefore a broad object of my invention to provide an
improved dental implant system.
[0010] It is a more specific object of my invention o provide an
improved dental implant system which is relatively inexpensive to
fabricate and use.
[0011] In another aspect, it is an object of my invention to
provide a dental implant system which is relatively easy to use to
obtain high quality results.
SUMMARY OF THE INVENTION
[0012] Briefly, these and other objects of the invention are
achieved by a method of growing additional maxillary or mandibular
bone in areas of atrophy and by the use of a related device to
accomplish the task. A pliable guided-tissue regeneration plate,
which holds it shape after being bent, is employed as a mating
component to a support screw or a dental implant and is secured to
the jaw structure by fixation of the guided-tissue regeneration
plate at a predetermined distance above or away from the surface of
the bone to the support screw or dental implant in order to create
a supported and protected space between the underside of the gum
tissue and the original bone which is free from muscular and
chewing pressure in order to promote bone growth.
[0013] The guided-tissue regeneration plate support and fixation
system can be mated with a support screw or screws which are
tenting screws designed to be mated with and then become intimately
a part of the guided-tissue regeneration plate in order to grow
bone in the space created by the guided-tissue regeneration plate
system prior to implant placement. Additionally, the guided-tissue
regeneration plate system can be utilized during implant placement
by creating space adjacent to a dehisced implant by fixation of the
guided-tissue regeneration plate directly to the implant in order
to grow bone height or width. A guided-tissue regeneration plate
according to the present invention can also be used by affixing it
to an existing dental implant that has been previously placed and
has undergone bone loss in order to regenerate new bone. The
guided-tissue regeneration plate support and fixation system is
adapted to be surgically removed after the bone has grown under its
surface at a later uncovering or implant placement surgery. In an
alternative preferred embodiment which provides particularly
successful results and which results in faster and better bone
regeneration and periosteum growth, the guided-tissue regeneration
plate consists of first and second integrated components including
a first support plate component having a peripheral region and a
generally open central portion and a fine mesh screen juxtaposed
over the central portion and fixed to the peripheral region
thereof. In a functionally equivalent variant of the alternative
preferred embodiment, the guided-tissue regeneration plate is
fabricated starting with an imperforate plate (for example, of
titanium) and then reducing the thickness of predetermined central
regions of the plate, a step which can be carried out, for example,
by employing a conventional photoresist mask over the plate in
conjunction with an acid etch. After the desired thickness of the
central regions has been obtained, the central regions may be
perforated with finely spaced apertures using, for example,
conventional laser machining techniques.
DESCRIPTION OF THE DRAWING
[0014] The subject matter of the invention is particularly pointed
out and distinctly claimed in the concluding portion of the
specification. The invention, however, both as to organization and
method of operation, may best be understood by reference to the
following description taken in conjunction with the subjoined
claims and the accompanying drawing of which:
[0015] FIG. 1 illustrates a bony ridge that has undergone
substantial loss;
[0016] FIG. 2 depicts a cross-section of a maxillary midline area
of an edentulous ridge showing the original size prior to bone
loss;
[0017] FIG. 3 shows the surrounding tissue first reflected away
from the bony ridge to expose the ridge in its entirety;
[0018] FIG. 4 depicts the mating of a guided-tissue regeneration
plate component of the invention to a support screw component of a
snap-fit embodiment;
[0019] FIG. 5 shows bone graft material packed beneath the plate
and against the existing bony ridge;
[0020] FIG. 6 shows how the bony ridge appears after the
guided-tissue regeneration plate support and fixation system has
been removed to expose the new bony ridge;
[0021] FIG. 7 depicts the placement of a large implant into the new
bony ridge;
[0022] FIG. 8 shows the placement of an implant into an atrophic
bony ridge;
[0023] FIG. 9 depicts the installation of a guided-tissue
regeneration plate using a screw supplied by an implant
manufacturer;
[0024] FIG. 10 illustrates the final result of the process shown
progressively in FIGS. 8, 9 and 10;
[0025] FIG. 11 illustrates the manner in which the guided-tissue
regeneration plate can be snap-attached over a modified healing
screw made to internally thread into a dental implant;
[0026] FIG. 12 depicts a non-perforated embodiment of the
guided-tissue regeneration plate;
[0027] FIG. 13 illustrates a snap configured support screw ready to
receive a guided-tissue regeneration plate;
[0028] FIG. 14 depicts the guided-tissue regeneration plate over
the snap configured support screw after the edges have been bent
down to create a space below the guided-tissue regeneration
plate;
[0029] FIG. 15 illustrates a perforated version of the
guided-tissue regeneration plate;
[0030] FIG. 16 depicts a guided-tissue regeneration plate being
secured to a guided-tissue regeneration plate support screw by a
small set screw; and
[0031] FIG. 17 illustrates the manner in which an exemplary healing
screw of the sort typically supplied by a dental implant
manufacturer can be employed to secure the guided-tissue
regeneration plate to a dental implant;
[0032] FIG. 18 shows in plan view a guided tissue regeneration
support plate used in an alternative preferred embodiment of the
invention;
[0033] FIG. 19 is a view similar to FIG. 18 illustrating the
optional use of stabilizing members added to the central,
substantially open region of the support plate;
[0034] FIG. 20 illustrates a fine mesh screen component used in the
alternative preferred embodiment of the invention;
[0035] FIG. 21. show a completed guided tissue regeneration plate
according to the alternative preferred embodiment of the invention
fabricated by integrating the screen shown in FIG. 20 to the
support plate shown in FIGS. 18 and 19;
[0036] FIG. 22 is a view similar to FIG. 21 illustrating a
reinforced central aperture;
[0037] FIG. 23 is an enlarged cross sectional view taken along the
lines 23-23 of FIG. 22;
[0038] FIG. 24 is a plan view of an imperforate plate used in a
variant process for preparing the alternative preferred embodiment
of the invention;
[0039] FIG. 25 is a plan view of a mask, overlaying the imperforate
plate, used to define predetermined central areas of the
imperforate plate to be reduced in thickness;
[0040] FIG. 26 is a plan view of the imperforate plate after the
predetermined central areas have been reduced in thickness; and
[0041] FIG. 27 is a plan view of a completed guided-tissue
regeneration plate prepared by the variant process after a
perforating step has been carried out.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0042] The described invention relates to a method of growing jaw
bone and to the related guided-tissue regeneration plate support
and fixation system by which an isolated and protected space free
from tissue impingement, occlusal loading, chewing forces, or
muscular pressure is created between the periosteum and the jaw
bone. This space is created by first placing either a dental
implant or a guided-tissue regeneration plate support and fixation
system tenting-type support screw into the jaw bone and then
coupling the guided-tissue regeneration plate to the support
screw.
[0043] The presently preferred embodiment of the support screws,
preferably made out of (but not limited to) titanium, are thin
shafted screws with a relatively high ratio between the greater
diameter to the minor diameter of the threads to give the maximum
bite and hold into the bone. Preferably, this ratio is at least
two. The head of the tenting-type support screw is placed above or
away from the bone a suitable distance of the space created in
order to grow bone. The screw head is configured to receive the
guided-tissue regeneration plate, thus allowing for most of the
head to be either in or under the guided-tissue regeneration plate
after it is engaged into a receiver cap of the head.
[0044] In another contemplated embodiment of the support screws,
the head of the support screw is internally axially threaded or is
provided with a threaded or non-threaded well allowing for a pin
with a small head resembling a micro thumbtack to extend through
the guided-tissue regeneration plate into the well and snap or
thread into place, thereby securing the guided-tissue regeneration
plate to the head of the tenting-type support screw. The support
screw is preferably fabricated to be very sharp at its tip which
includes a self-starting flute in order to facilitate
self-threading for facilitating placement.
[0045] The guided-tissue regeneration plate is preferably made of
thin titanium sheet metal having a peripheral thickness of around 5
to 10 thousandths of an inch. This thickness allows for the
material to be thin enough to be bent into shape, but rigid enough
to hold its shape after being bent and molded. The present material
of choice is Grade 1 titanium which is the fully annealed form of
titanium advantageously characterized in that it will not spring
back after being bent.
[0046] The plates are fabricated with a precise aperture proximate
the center or wherever needed in order to allow for a precise union
and mating to the support screw or receiver cap of the healing
screw of a dental implant, thus giving a secure fixation, by
indirect means, to the jaw bone. The central area of the
guided-tissue regeneration plate is preferably thicker in order to
provide more support and rigidity than the peripheral region. The
combination of the support screw and the thicker area of the plate
near the center prevents the guided-tissue regeneration plate from
caving-in in the area where maximum support is needed when
overlying pressure, such as muscular pressure, chewing forces, or
any other premature loading onto the guided-tissue regeneration
plate support and fixation system, is later applied.
[0047] The guided-tissue regeneration plate can optionally be
perforated to allow for better overlying tissue healing as well as
to promote the exchange of nutrients and blood supply between the
bone graft and the overlying tissue. Generally, the central,
thicker, more supportive area is not perforated to obtain more
support. Typically, the number and size of the perforations is less
concentrated than the amount of solid space to create a more
supportive plate at a thinner dimension. If a completely
imperforate barrier is desired to isolate all transfer of unwanted
epithelial cells into the bone graft area, then the guided-tissue
regeneration plate is fabricated imperforate except for the
generally centrally disposed aperture for fixing the plate to its
support screw.
[0048] However, if a temporary period of isolation from epithelial
cells is desired to create a membrane barrier from epithelial cells
for a limited period of time which allows for the exchange of
nutrients, ions, and tissue fluid or perhaps blood supply, then a
resorptive barrier such as Vicryl.TM., collagen, resorptive
hydroxyapatite crystals or Guidor.TM. can be applied to the under
or over side of the guided-tissue regeneration plate to seal the
perforations, then resorbing a limited time later after the system
is installed.
[0049] If a non-resorptive semi-permeable result is desired, then
the perforations can be covered by applying a suitable material
such as PTFE fibers. After a period of several months have passed,
the entire system is removed and then the implants are either
simultaneously placed during this surgery or uncovered by placing
healing caps into the implants. If the only desired effect is to
create a better ridge for the stabilization of a denture, then the
system may be left in place indefinitely.
[0050] Having now discussed the fundamentals of the present
invention, attention is invited to the several FIGS. for an
alternative and clarifying disclosure as the discussion
proceeds.
[0051] FIG. 1 shows an exemplary existing midline cross-section of
a maxillary edentulous ridge which has undergone substantial bone
loss. For orientation purposes, landmarks can be identified by the
palatal bone 1, the floor of the nose 2, the bony ridge 3, and the
gum tissue 4.
[0052] FIG. 2 depicts a cross-section of a maxillary midline area
of an edentulous ridge showing the original size prior to bone loss
(the gum tissue is not shown in this view). Reference is taken to
the marrow space 5, the cortical bone 6 and the current size of the
ridge 7 after bone loss and to the area of the original size 8 of
the ridge prior to atrophy or bone loss.
[0053] Referring now to FIG. 3, in order to place a guided-tissue
regeneration plate support and fixation system according to the
present invention, the tissue is first reflected away from the bony
ridge to expose the ridge in its entirety. The palatal gum tissue 9
is reflected 9, the facial gum tissue 10 is reflected, and a
guided-tissue regeneration plate support screw 11 is placed into
the bony ridge.
[0054] FIG. 4 depicts the mating of the guided-tissue regeneration
plate 12 to a guided-tissue regeneration support screw 11 of the
snap-fit embodiment. (The gum tissue is not shown.) The space 13 is
the area where new bone will grow, the space having been created by
the guided-tissue regeneration plate support and fixation system of
the invention. The guided-tissue regeneration plate support screw
11 is placed into the bony ridge 3. After the guided-tissue
regeneration plate 12 is affixed to the guided-tissue regeneration
plate support screw 11 by snapping it in place, the plate is molded
into shape by bending the edges down as shown.
[0055] As shown in FIG. 5, once the guided-tissue regeneration
plate 12 has been molded into place, then bone graft material 14 is
packed beneath the plate 12 and against the existing bony ridge 3.
After a period of approximately four-to-eight months, a new bony
ridge will form within the space created by the guided-tissue
regeneration plate support and fixation system. (Gum tissue not
shown.)
[0056] Thus, FIG. 6 shows how the bony ridge appears after the
guided-tissue regeneration plate support and fixation system has
been removed to expose the new bony ridge 15. A small hole 16
remains after the removal of the guided-tissue regeneration plate
support screw. (Gum tissue not shown.)
[0057] FIG. 7 depicts the placement of a large implant 17 into the
new bony ridge. A tooth can be attached to the implant later.
[0058] FIG. 8 shows the placement of an implant 17 into an atrophic
bony ridge 3. In this environment, the implant is not fully encased
in bone resulting in an exposed area 18 of the implant outside the
confines of the existing bone 3.
[0059] FIG. 9 depicts the installation of a guided-tissue
regeneration plate 12 by inserting the healing screw 19 supplied by
the implant manufacturer which can be used in place of a
tenting-type support screw to mate the guided-tissue regeneration
plate 12 directly to the implant 17. This screw 19 extends through
the aperture of the guided-tissue regeneration plate 12 and is thus
used instead of the snap-type embodiment previously described. The
space 13 created by the guided-tissue regeneration plate 12 is
filled with bone graft material, thus covering the exposed portion
of the dental implant 18 which is out of the confines of the
existing resorbed bony ridge 3.
[0060] FIG. 10 illustrates the final result of the process shown
progressively in FIGS. 8, 9, 10 after the removal of the
guided-tissue regeneration plate (not shown) by revealing that the
dental implant 17 is now covered with new bone 20 that has grown
around the dental implant after four-to-eight months of healing
time and the subsequent removal of the guided-tissue regeneration
plate system. As will be apparent to those skilled in the art,
after the removal of the guided-tissue regeneration plate, a post
has been placed into the dental implant 17 as normal followed by a
crown or tooth 22 which is secured to the post in the well known
manner.
[0061] FIG. 11 illustrates the manner in which the guided-tissue
regeneration plate 12 can be snap-attached over a modified healing
screw 23 made to internally thread into a dental implant 17. The
modified healing screw 23 has a receiver cap 24 adapted to receive
the generally centrally disposed aperture in the guided-tissue
regeneration plate 12.
[0062] FIG. 12 depicts a non-perforated embodiment 30 of the
guided-tissue regeneration plate, particularly illustrating the
generally central aperture 31 by which the guided-tissue
regeneration plate may be secured using a screw as previously
described.
[0063] FIG. 13 depicts the snap configured support screw 11 ready
to receive the guided-tissue regeneration plate 30 through the
aperture 31. Attention is also directed to the cross-section of the
guided-tissue regeneration plate 30 which includes a relatively
thick central region 32 and a thinner peripheral region 33 as
previously described.
[0064] FIG. 14 depicts the mating of the guided-tissue regeneration
plate 30 over the snap configured support screw 11 after the edges
have been bent down to create the space below the guided-tissue
regeneration plate.
[0065] FIG. 15 illustrates a perforated version 35 of the
guided-tissue regeneration plate which allows for blood supply to
pass freely through the plate. Note the generally centrally
disposed aperture 25.
[0066] FIG. 16 depicts a guided-tissue regeneration plate 35 being
secured to a guided-tissue regeneration plate support screw 26 by a
small set screw 27 which is placed through the aperture 25 in the
guided-tissue regeneration plate and into the support screw 26
which has an internally threaded, axially oriented blind hole 36 in
its top.
[0067] FIG. 17 illustrates the manner in which an exemplary healing
screw 19 of the sort typically supplied by a dental implant
manufacturer can be employed to secure the guided-tissue
regeneration plate 12 to the dental implant 17.
[0068] While the guided-tissue regeneration plate system described
above has worked well, experience and further development of the
fundamental concept has resulted in an alternative preferred
embodiment for the guided-tissue regeneration plate component which
is discussed below in conjunction with FIGS. 18-21. Thus, referring
to FIG. 18, there is shown a guided-tissue regeneration support
plate 40 which is a first component of the alternative preferred
embodiment for the guided-tissue regeneration plate. The support
plate 40 has generally open regions 41, 44 defined, in the
exemplary configuration, by integral struts 42 radiating from a
central inner support ring 43 to the main body of the support
plate. If desired, the central inner support ring 43 and defined
space 44 may be dimensioned and configured to serve the same
fixation purpose as the apertures 31 and 35 in the respective
guided-tissue regeneration plates 30, 35 as described above.
[0069] The main body of the support plate 40, i.e., that portion
which is generally outboard the struts 42, the inner support ring
43 and the open regions 41, 44, is somewhat thicker than the
guided-tissue regeneration plates 30, 35 previously described. For
example, when the presently preferred material, titanium, is used,
the thickness of the support plate 40 may be on the order of
0.008-0.025 of an inch and preferably about 0.020 of an inch. The
material, as noted with respect to the guided-tissue regeneration
plates 30, 35, should be bio-compatible, and other metals which are
suitable include chromium cobalt alloy and Teflon-coated surgical
steel.
[0070] It will be understood that any suitable configuration of the
support plate 40 may be employed to provide a peripheral region of
sufficient strength and rigidity as to be readily manually shaped
to the contours necessary to be fitted to the region above the bony
ridge of a given patient as previously described above while
providing substantial open regions 41, 44 surrounded by the
peripheral region. However, the configuration shown in FIG. 18 has
proven to be a good combination of strength and intended purpose.
Preferably, in order to both increase the moldability of the
support plate 40 and to expose the underlying bone and tissue to
the passage of nutrients for the additional reasons discussed above
with respect to the guided-tissue regeneration plate 35, numerous
perforations 45 are provided in the support plate. Because of the
increased thickness of the support plate 40 in comparison to that
of the guided-tissue regeneration plate 35, the perforations 45 are
preferably mutually closely spaced consistent with not compromising
the strength of the support plate.
[0071] Referring also to FIG. 19, the struts 42 should be as narrow
as reasonably possible while remaining not subject to easy tearing.
For example, widths for the struts 42 within the range 0.020-0.030
of an inch, and preferably about 0.025 of an inch, are suitable
when the presently preferred material, titanium, is used. Should
the central portion still be somewhat week for the intended purpose
(which will become more apparent below), one or more supplementary
rectangular struts 48 and/or one or more intermediate, minor struts
46, 47 encompassing the center of the support plate may be fixed to
the struts 42 to provide increased rigidity, either on the upper or
lower plane of the support plate 40. The widths of the
supplementary struts 48 may fall within the same range as those of
the struts 42 while the widths or diameters (if titanium wire is
used), i.e., the largest transverse dimension, of the minor struts
46, 47 may be smaller yet, falling within the range 0.010-0.020 of
an inch, preferably about 0.015 of an inch. The method of fixation
of the supplementary strut(s) 47, 47, 48 may be by any suitable
expedient such as welding, spot welding, laser welding, adhesive or
sintering.
[0072] Attention is now directed to FIG. 20 which shows a second
component of the alternative preferred embodiment for the
guided-tissue regeneration plate. This second component is a fine
mesh screen 50. When the presently preferred material, titanium, is
used, the diameter of the wire may be in the range of about
0.002-0.006 of an inch, and preferably about 0.003 of an inch
disposed in a fine mesh weave on the order of 10.times.10 wires per
inch to 200.times.200 wires per inch and preferably about
50.times.50 per inch. Referring also to FIG. 21, the fine mesh
screen 50 is juxtaposed onto the support plate 40 generally
centrally disposed over the open areas 41 and fixed in place by any
means suitable to the material(s) employed. When the presently
preferred material, titanium, is used for both components, welding
(particularly spot or laser welding), an adhesive or sintering may
be employed. Sintering (i.e., heating the complete assembly until
the titanium components have fused at the points of abutment) has
been found to give particularly good results, and, if the
supplementary struts 48 and/or minor struts 46, 47 are employed,
they may be integrated into the structure during the same sintering
step.
[0073] When alternative materials, such as chromium cobalt alloy
and Teflon-coated surgical steel, are selected, the size parameters
discussed above for titanium are also suitable, and the fixation of
the fine mesh screen 50 to the support plate 40 may be carried out
in the same manner when chromium cobalt alloy is employed. However,
when Teflon-coated surgical steel is used, a compatible fixation
method must be employed. For example, the Teflon coating may be
first scraped away in the regions of abutment between the two
components before the joining step is carried out, or a special
purpose adhesive may be used. Preferably, however, the Teflon
coating is more practically applied after the two-piece structure
has been fabricated.
[0074] The resulting two-piece (plus supplementary and/or minor
struts) guided-tissue regeneration plate 49 shown in FIG. 21 can
then be used in the process described above with notably improved
results with respect to the speed and quality with which jaw bone
is regenerated along a patient's bony ridge and thicker and more
healthy overlying periosteum. Consequently, the long term outlook
for the integrity of subsequent dental implants is correspondingly
improved, a more satisfactory result having been obtained more
quickly.
[0075] In order to insure a secure fixation of the two-piece
guided-tissue regeneration plate 49 to the support structure which
is fixed to the jaw bone of a patient as previously described with
respect to the guided-tissue regeneration plates 30, 35, it may be
useful to locally reinforce the central inner support ring 43 which
defines the central aperture 44 which functionally corresponds to
the apertures 31, 25. FIGS. 22 and 23 illustrate a reinforced
central inner support ring 43. More particularly, as best shown in
the enlarged fragmentary cross section of FIG. 23, the thickness of
the central inner support ring 43 may be augmented by any suitable
means such as by stacking additional material 43A over the support
ring 43 which is integral with the struts 42 as previously
described.
[0076] Preparation of a variant version of the second preferred
embodiment is illustrated in FIGS. 24-27. FIG. 24 shows an
imperforate monolithic plate 60 having peripheral outer dimensions
corresponding to those of the guided-tissue regeneration plate 49
shown in FIG. 22. As previously mentioned, a preferred material is
titanium plate having a thickness of about 0.008-0.025 of an inch
and preferably about 0.012 of an inch. The imperforate plate 60 is
subjected to further processing to obtain the desired guided-tissue
regeneration plate as a unitary structure.
[0077] Thus, referring now to FIG. 25, in anticipation of reducing
the thickness of predetermined central regions of the plate 60, a
suitable configured mask 61 is prepared and juxtaposed overlaying
one surface of the plate. The mask 61 may be a separate
stencil-like layer or may be deposited directly on the surface of
the plate 60 by a conventional technique such as by depositing a
photo-resist layer applied in the desired pattern; i.e., a pattern
which will shield the areas of the plate 60 which are not to be
reduced in thickness. Accordingly, the areas which are not coated
or otherwise masked off are subject to reduction in thickness.
Because the open region pattern employed in the example describing
the first version of the second preferred embodiment of the
guided-tissue regeneration plate has been found to work well, it is
also used to describe the second version. Still referring to FIG.
25, radial struts 64 of the mask 61 define a series of
circumferentially distributed openings 62 while arms adjoining
adjacent radial struts 64 define supplementary struts 65 which
corresponds to the supplementary struts 48 shown in FIGS. 19, 21
and 22 and discussed above. The rectangular configuration of the
supplementary struts 65 and the inner ends of the radial struts 64
define additional openings 67. The inner ends of the radial struts
64 each terminate at a ring 66 which circumscribes central mask
opening 63.
[0078] Once the mask 61 has been emplaced over the plate 60, the
masked surface can be subjected to a conventional acid etch to
remove unprotected metal and hence reduce the thickness of the
plate 60 in the unmasked areas to the previously discussed range of
0.002-0.006 of an inch and preferably about 0.003 of an inch. The
rate and extent of the metal removal can be controlled, as well
known in the art, by selecting the type of acid, its concentration
and temperature and the length of time the plate is subjected to
the acid.
[0079] FIG. 26 shows the plate 60A after the acid etch step has
been completed. Thus, regions 68, 69, 70 will be understood to be
of diminished thickness while the strut regions 71, supplementary
strut regions 72, central ring region 73 and peripheral region 74
remain at the original thickness of the plate because they were
protected by the mask during the etching operation.
[0080] The second variant of the second preferred embodiment of the
guided-tissue regeneration plate is competed by perforating its
surface with a large number of closely spaced apertures, typically
circular in shape. As shown in FIG. 27, the guided-tissue
regeneration plate 60B has been pierced by numerous closely spaced
apertures 75 in the regions 71, 72, 73, 74 of the plate which were
not reduced in thickness. In the regions 68, 69 which were reduced
in thickness, the plate is pierced even more densely with numerous
closely spaced apertures 76. The central aperture 70 is opened
through the plate 60B during the finishing process to serve as a
fixation screw receiving opening in the same manner as previously
described with respect to the central aperture 44 (FIGS. 22, 23) of
the two-piece first variant of the alternative preferred embodiment
for the guided-tissue regeneration plate.
[0081] The size and spacing of the apertures in both the original
thickness and the reduced thickness regions of the guided-tissue
regeneration plate 60B affects both the porosity and the mechanical
pliability of the individual regions. The spacing can be either
random as shown for the majority of the areas in FIG. 27 or in a
definite pattern as shown in the regions 76 (a thinned-down region)
and 77 (an original thickness region--not enlarged). The regions 76
and 77 are contrasted by the use of smaller apertures and finer
spacing in the reduced thickness region 76, thus achieving
increased porosity. In contrast, the larger apertures and wider
spacing employed in the original thickness region 77 provides a
stiffer, but still compliant, structure for the peripheral region
74 which achieves a structure mechanically well-adapted for
emplacement and subsequent maintenance of its position and
configuration in use.
[0082] It was noted above that one or more minor struts (e.g., the
minor struts 46, 47 shown in FIGS. 19, 21) may be provided as
necessary to ensure sufficient rigidity to the screened portion of
the first variant of the alternative preferred embodiment for the
guided-tissue regeneration plate. Corresponding minor struts may
also be incorporated into the second variant of the alternative
preferred embodiment for the guided-tissue regeneration plate shown
in FIG. 27 by either making provision for such in the mask 61 or by
later affixing them, as separate components in the manner
previously described, to the unitary structure.
[0083] While the presently preferred material for either version of
the alternative preferred embodiment is titanium, the use of other
materials, non-resorptive and resorptive, as discussed above may be
employed. As with the previously described embodiments, after the
desired bone regeneration has been achieved, the variant preferred
embodiment of the guided-tissue regeneration plate may be left in
place or removed prior to the implantation process as may be
appropriate for a given patient. Further, as also previously
described with respect to the guided-tissue regeneration plate 35,
if a temporary period of isolation from epithelial cells is desired
to create a membrane barrier from epithelial cells for a limited
period of time which allows for the exchange of nutrients, ions,
and tissue fluid or perhaps blood supply, then a resorptive barrier
such as Vicryl.TM., collagen, resorptive hydroxyapatite crystals or
Guidor.TM. can be applied to the top or bottom side of the
guided-tissue regeneration plates 49, 60B to seal the perforations,
then resorbing a limited time later after the system is
installed.
[0084] A performance improving enhancement which can be employed
either with the guided-tissue regeneration plate described and
claimed in the aforementioned parent U.S. Pat. No. 5,839,899 or
with the guided-tissue regeneration plates described and claimed
herein is to decrease the surface tension, and hence increase the
"wetability", of the guided-tissue regeneration plate surfaces.
This effect can be achieved in several ways. For example,
subjecting the guided-tissue regeneration plate to a plasma spray
or gently blasting it with fine to coarse grit abrasive or
subjecting it to a suitable acid etchant for a suitable period will
achieve the desired result. This slight roughening of the surface
of the guided-tissue regeneration plate serves to promote better
tissue adhesion and consequently decreases susceptibility to
infection or exposure of the plate. In a variant of this
enhancement, only the top (tissue side) of the guided-tissue
regeneration plate is roughened in order that the tissue will
adhere to it, yet the plate can be readily peeled away in due
course from the underlying, newly-formed bone.
[0085] Thus, while the principles of the invention have now been
made clear in an illustrative embodiment, there will be immediately
obvious to those skilled in the art many modifications of
structure, arrangements, proportions, the elements, materials, and
components, used in the practice of the invention which are
particularly adapted for specific environments and operating
requirements without departing from those principles.
* * * * *