Note: Descriptions are shown in the official language in which they were submitted.
CA 02484475 2004-10-12
ADJUSTABLE DENTAL IMPLANT DRILL GUIDE APPARATUS
FIELD OF THE INVENTION
The present invention relates in general to apparatus for guiding a drill bit
to bore a
socket in a human jawbone, for receiving an implant for supporting a dental
prosthesis. More
particularly, the invention relates to such apparatus having means for
selectively adjusting the
lateral position and angular orientation of the drill bit.
BACKGROUND OF THE INVENTION
Dental implants are an increasingly popular alternative to dentures for
replacing missing
teeth. To replace a single missing tooth using the implant procedure, a
cylindrical socket (or
osteotomy) is bored into the jawbone - the maxilla (upper jawbone) or the
mandible (lower
jawbone) as the case may be. A post-like metal implant (typically but not
necessarily
cylindrical, and preferably made of titanium or a titanium alloy) is then
inserted into the socket.
The implant typically has external tapping threads so that it can be screwed
into the socket.
Following insertion into the socket, the implant becomes integrated into the
jawbone structure
by a natural process known as osteointegration. Once osteointegration has
occurred, a
prosthetic tooth may be attached to the implant. To replace two or more
adjacent teeth, two or
more sockets are drilled into the jawbone to receive metal implants, and then
a multiple-tooth
prosthesis is attached to the implants.
For an optimally successful implant procedure, the metal implant (or implants)
must be
securely anchored in the jawbone, and for this reason the axis of the sockets
for the implants
should be oriented as centrally as possible within the thickness of the
jawbone. If a socket is
drilled too close to either the inner or outer side of the jawbone, there may
not be enough bone
material on that side to provide satisfactory structural support for an
implant. Ideally, there will
be about the same thickness of bone on each side of the socket. To achieve
this desirable result,
the socket should be started at a point substantially central to the ridge of
the mandible or
maxilla (as the case may be), and it should be drilled from that point at an
appropriate
transverse angle to ensure that it stays centrally located as drilling
progresses into the bone.
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In addition to its lateral or buccal-lingual position (i.e., transverse to the
mandibular or
maxillar ridge) and transverse angular orientation, an implant socket's
longitudinal or mesio-
distal position and angular orientation must also be controlled within fairly
close tolerances.
Prostheses for dental implants are fabricated for attachment to implants
having pre-selected
angular orientations; so an implant will assume substantially the same angular
orientation as the
socket into which it is inserted. Therefore, if an implant socket is drilled
at an angle varying
more than slightly from the pre-selected angle, the position of implant after
insertion into the
socket will be offset from the corresponding attachment point of the
prosthesis, thus making
satisfactory installation of the prosthesis difficult or impossible. It will
also be readily
appreciated that inaccurate lateral or longitudinal positioning of an implant
socket may
complicate or preclude satisfactory prosthesis installation.
For all the foregoing reasons, it is important for oral surgeons drilling
implant sockets to
ensure proper positioning and angular alignment of the sockets. Some surgeons
may rely
merely on visual observation and judgment to determine socket location and
alignment, but this
method entails considerable risk. If the surgeon's judgment is inaccurate, or
if the surgeon's
manipulation of the drill is imprecise, the result may be an unusable socket.
It is preferable,
therefore, to use some physical apparatus for guiding the drill bit along a
desired path into the
jawbone, and the prior art discloses several known apparatus directed to this
purpose.
U.S. Patent No. 5,556,278 (Meitner) discloses a method of making a template
for
guiding a drill bit for drilling an implant socket. The first step is to cast
a model of the affected
portion of the patient's jaw, using methods and materials well known in the
field of dentistry.
The model provides a very accurate three-dimensional representation of the gum
surface in the
edentulous (i.e., toothless) region intended to receive implants, a,s well as
any teeth adjacent to
the edentulous region. One or more holes are drilled into the model in the
region
corresponding to the edentulous region of the patient's jaw (one hole for each
intended
implant), with a starting point and angular orientation corresponding to the
intended position
and orientation of the eventual implant socket. A guide post, typically made
of metal and
having an outer diameter corresponding to the diameter of intended implant
socket, is inserted
into each of the holes. A cylindrical guide tube, having an interior diameter
slightly larger than
the diameter of the guide post, is placed over the guide post. A template is
then formed by
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applying a molding material (e.g., an acrylic material) around the guide tube
(or tubes). When
the molding material has dried or set, the template is removed from the model
with the guide
tubes embedded into it. The template is then inserted into the patient's
mouth, whereupon the
oral surgeon proceeds to drill the desired implant sockets using the guide
tubes in the template
(i.e., with the drill bit passing through the tubes).
The Meitner method produces satisfactory results provided that the guide tubes
have
been properly positioned in the template, but this is dependent on the
position and orientation
of the holes drilled into the model, which in turn involves an element of
judgment and therefore
is susceptible to inaccuracy. To confirm that the guide tubes are properly
positioned, the
Meitner method provides that the guide tubes are made with radiopaque material
so that their
position and orientation can be checked before the sockets are drilled by
means of radiologic or
tomographic visualization with the template positioned in the patient's mouth.
The problem
with this, however, is that if the guide tubes are found to be
unsatisfactorily positioned, there is
no way to correct this condition, so the template must be discarded and a new
one built. This
obviously is inefficient and costly.
U.S. Patent No. 5,800,168 (Cascione et al.} discloses a template with a guide
tube that
can be adjusted with respect to both lateral position and angular orientation.
A radiopaque
guide tube is rotatably mounted inside a first radio-transparent housing which
in turn is slidably
mounted inside a second radio-transparent housing bonded into an acrylic
template. The guide
tube is rotatable about an axis generally parallel to the ridge of the jawbone
so that its angular
orientation transverse to the ridge can be adjusted. The first housing is
slidable within the
second housing transversely to the ridge of the jawbone, thus allowing for
adjustment of the
lateral position of the guide tube. The template is placed in the patient's
mouth with the guide
tube in a provisional or test position, whereupon the guide tube is
radiologically visualized to
confirm whether the guide tube is satisfactorily aligned with the jawbone. If
it is not
satisfactorily aligned, adjustments can be made in the plane transverse to the
jawbone ridge, by
rotating the tube and sliding the first housing within the second housing to
achieve a desired
transverse position. The guide tube's position can then be checked by further
radiologic
visualization. This process can be repeated as many times as necessary until
the guide tube is
positioned and oriented as desired, whereupon it may be fixed into position
within the template
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by introducing a filler material into the first and second housings. An
implant socket may then
be drilled into the jawbone, with the drill bit passing through the guide tube
in the template.
The Cascione apparatus enhances the oral surgeon's ability to ensure
satisfactory
positioning and orientation of implant sockets by providing for adjustment of
the guide tube,
but this adjustability is limited to lateral positioning and angular
adjustment about one axis
only. Cascione has an additional drawback in that it entails specialized (and
thus costly)
construction by virtue of the pivoting guide tube and slidable housing
assembly.
For the foregoing reasons, there is a need for an adjustable dental implant
drill guide
apparatus that allows for multi-axial adjustment of an implant socket's
angular orientation
relative to the maxillar or mandibular arch. Furthermore, there is a need for
dental implant drill
guide apparatus that provides for adjustment of lateral position relative to
the maxillar or
mandibular arch, in addition to mufti-axial angular adjustability. The present
invention is
directed to these needs.
BRIEF SUMMARY OF THE INVENTION
In general terms, the present invention is an improved drill guide apparatus
having a
guide tube for receiving a drill bit to drill an implant socket in a patient's
jawbone. The drill
guide apparatus is adapted such that the angular orientation of the guide tube
can be adjusted
about any axis, to ensure that the guide tube is optimally oriented prior to
drilling of the implant
socket. This adjustability is accomplished by disposing the guide tube within
a spherical
swivel ball that is rotatably retained, in ball-and-socket fashion, within a
template formed on a
model of the affected portion of the patient's jaw. The guide tube projects
outward (i.e., away
from the jaw) from the swivel ball, through an opening in the template, so
that it can be
manipulated in "joystick" fashion, to orient the guide tube as desired.
Accordingly, in a first aspect the present invention is a drill guide
apparatus for use in
drilling an implant socket into a jawbone of a dental patient, said drill
guide apparatus
comprising:
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(a) a template having an inner surface substantially conforming to the
surficial
mucosal contours of an edentulous portion of the patient's jaw, and also
having
an outer surface;
(b) a substantially spherical swivel ball retainingly disposed within the
template so
as to be mufti-axially rotatable relative thereto; and
(c) a cylindrical guide tube passing at least partially through the swivel
ball and
extending outward from the swivel ball through a guide tube opening in the
outer surface of the template;
wherein:
(d) the drill guide apparatus may be positioned in the patient's mouth with
the inner
surface mating with the corresponding edentulous portion of patient's jaw;
(e) the guide tube may be rotatingly manipulated about multiple axes into a
selected
angular orientation relative to the template; and
(f) a drill bit may be inserted through the guide tube to drill an implant
socket into
the jawbone, said socket being for receiving an implant to support a dental
prosthesis.
In the preferred embodiment, the template is formed from a radio-transparent
material,
and the guide tube has a radiopaque marking (meaning, for purposes of this
patent
specification, a marking made with a material through which electromagnetic
waves such as X-
rays will not readily pass), to facilitate radiologic visualization of the
guide tube's position and
angular orientation relative to the patient's jawbone prior to drilling a
socket.
In one embodiment, the template is vacuum-formed from an inner layer and an
outer
layer of acrylic material, with the swivel ball being disposed between said
inner and outer
layers, and with the guide tube opening being formed in the outer layer.
Alternatively, the
template may be made with light-cured acrylic material, using methods and
materials well
known in the dental arts.
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In alternative embodiments of the drill guide apparatus, the swivel ball is
slidably
mounted within an elongate swivel ball housing retainingly disposed within the
template so that
both the lateral position and the angular orientation of the socket can be
adjusted. The swivel
ball housing has a central chamber enclosed by two opposing sidewalk. The
inner face of each
sidewall has a concave, partially-cylindrical groove running substantially the
length of the
sidewall, with the grooves in the sidewalls being substantially parallel. The
radius of the
grooves is substantially equal to the radius of the swivel ball, so the swivel
ball can slide
laterally within the grooves while still being multi-axially rotatable for
angular adjustment of
the guide tube. In these alternative embodiments, the swivel ball housing may
be disposed
either substantially transverse to or substantially aligned with the ridge of
the patient's
jawbone, depending on the plane in which lateral positional adjustment of the
swivel ball and
guide tube is desired.
The swivel ball may be formed from any suitable radio-transparent material,
such as an
acrylic material.
The guide tube may have a handle for manipulating the guide tube into a
desired
angular orientation. Alternatively, the guide tube may have a tool slot formed
into its outer
end, for receiving a tool that may be used for adjusting the angular
orientation of the guide
tube.
In a second aspect, the present invention is a swivel ball assembly, for use
with a dental
implant drilling guide template, said swivel ball assembly comprising:
(a) a substantially spherical swivel ball; and
(b) a cylindrical guide tube passing at least partially through the swivel
ball and
extending outward from the swivel ball;
said swivel ball assembly being adapted to be retainingly disposed within a
template having an
inner surface substantially conforming to the surficial mucosal contours of an
edentulous
portion of a dental patient's jaw, such that the swivel ball assembly is mufti-
axially rotatable
relative to the template.
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In a third aspect, the present invention is a drill guide apparatus for use in
drilling an
implant socket into a jawbone of a dental patient, said drill guide apparatus
comprising:
(a) a template having an inner surface substantially conforming to the
surficial
mucosal contours of an edentulous portion of the patient's jaw, and also
having
an outer surface;
(b) an elongate swivel ball housing retainingly disposed within the template,
wherein:
b.l the swivel ball housing has a central chamber enclosed by two opposing
sidewalls;
b.2 the swivel ball housing defines a guide tube opening into the central
chamber; and
b.2 the inner face of each sidewall defines a concave, partially-cylindrical
groove running substantially the length of the sidewall, with the grooves
in the sidewalk being substantially parallel and having substantially the
same radius of curvature;
(c) a substantially spherical swivel ball having a radius of curvature
substantially
corresponding to the radius of the grooves in the side walls of the swivel
ball
housing, said swivel ball being disposed within the central chamber of the
swivel ball housing so as to be slidable within the sidewall grooves of the
housing and also as to be mufti-axially rotatable; and
(d) a cylindrical guide tube passing at least partially through the swivel
ball and
extending outward from the swivel ball through the guide tube opening in the
swivel ball housing;
wherein:
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(e) the drill guide apparatus may be positioned in the patient's mouth with
the
template substantially coinciding with the corresponding edentulous portion of
patient's jaw;
(f) the swivel ball may be slidingly manipulated into a selected position
within the
swivel ball housing;
(g) the guide tube may be rotatingly manipulated about any axis into a
selected
angular orientation; and
(h) a drill bit may be inserted through the guide tube to drill an implant
socket into
the jawbone, for receiving an implant to support a dental prosthesis.
In a fourth aspect, the present invention is a swivel ball housing, for use
with a dental
implant drilling guide template, said swivel ball housing having two opposing
sidewalls
enclosing a central chamber enclosed by two opposing sidewalk, wherein:
(a) the swivel ball housing defines a guide tube opening into the central
chamber;
(b) the inner face of each sidewall defines a concave, partially-cylindrical
groove
running substantially the length of the sidewall;
(c) the grooves in the sidewalk are substantially parallel and have
substantially the
same radius of curvature
comprising:
(d) a substantially spherical swivel ball; and
(e) a cylindrical guide tube passing at least partially through the swivel
ball and
extending outward from the swivel ball;
said swivel ball assembly being adapted to be retainingly disposed within a
template having an
inner surface substantially conforming to the surficial mucosal contours of an
edentulous
portion of a dental patient's jaw.
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BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will now be described with reference to the
accompanying figures, in which numerical references denote like parts, and in
which:
FIGURE 1 is a perspective view of a model of an edentulous portion of a
patient's jaw, fitted with a drill guide apparatus in accordance with a first
embodiment of the invention.
FIGURE 2 is a cross-sectional view through the template and one of the swivel
balls of the embodiment illustrated in Figure 1.
FIGURE 3 is a perspective view of a model of an edentulous portion of a
patient's jaw, fitted with a drill guide apparatus in accordance with a second
embodiment of the invention.
FIGURE 4 is an isometric view of the swivel ball housing of the embodiment
illustrated in Figure 3.
FIGURE 4A is a cross-sectional view along Line A-A in Figure 4.
FIGURE 5 is a perspective view of a model of an edentulous portion of a
patient's jaw, fitted with a drill guide apparatus in accordance with a third
embodiment of the invention.
FIGURE 6 is an isometric view of the swivel ball housing of the embodiment
illustrated in Figure S.
FIGURE 6A is a cross-sectional view along Line A-A in Figure 6.
FIGURE 6B is a cross-sectional view along Line B-B in Figure 6.
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Figure 1 illustrates a dental implant drill guide apparatus, generally
designated by
reference numeral 10, in accordance with a first embodiment of the present
invention. In
Figure 1, the apparatus 10 is shown in position on a cast model 70 of a
portion of a dental
S patient's lower dentition, including all existing teeth 70 an edentulous
area in which it is
intended to drill a socket to receive one or more implants for anchoring a
dental prosthesis to
replace one or more missing teeth. Although Figure 1 and other Figures in this
specification
illustrate the invention only in association with a patient's lower jaw, it
will be appreciated that
the invention may also be readily adapted for use in drilling sockets for
implants to replace
missing upper teeth. The Figures also show the edentulous area as being at the
back of the jaw,
but this is for general illustrative purposes only; it will be appreciated
that the invention may be
readily adapted for use in edentulous area of any size and in any region of
the patient's upper or
lower j aw.
Referring to Figures 1 and 2, the apparatus 10 includes a template 20A having
an inner
surface 21 and an outer surface 23. The template 20A is formed on the cast
model 70, with the
inner surface 21 substantially conforming to the contours of the model 70 in
affected contact
areas. For reasons to be explained subsequently, the template 20A is made from
a radio-
transparent material (meaning, for purposes of this patent specification, a
material through
which electromagnetic waves such as X-rays will readily pass). In the
preferred embodiment,
the template 20A is made from an acrylic material. At least one substantially
spherical swivel
ball 30 is rotatably retained in or by the template as conceptually
illustrated in Figure 2. The
swivel ball 30 is made from a radio-transparent material, and not necessarily
from the same
radio-transparent material as the template 20A. In the preferred embodiment,
the swivel ball 30
is made from an acrylic material.
As previously indicated, the swivel ball 30 is rotatably retained in or by the
template, in
such fashion that the swivel ball 30 can rotate about multiple axes, in the
same general way as a
ball-and-socket joint. In the preferred embodiment, as best illustrated in
Figure 2, the rotatable
retention of the swivel ball 30 by the template 20A is achieved by making the
template 20A
template from inner and outer layers 22, 24 of radio-transparent material,
preferably an acrylic
CA 02484475 2004-10-12
material, and preferably using vacuum-forming techniques that are well known
in the art. In a
template 20A formed using such techniques, the swivel ball 30 is sandwiched
between the
inner and outer layers 22, 24 of the template 20A, as shown in Figure 2, with
the inner and
outer layers 22, 24 of the template 20A being deformed so as to create a
cavity that at least
partially conforms to the spherical shape of the swivel ball 30, effectively
forming a "socket" in
which the swivel ball 30 can rotate.
The inventor has found that vacuum-forming techniques, as described above, can
be
effectively used to encapsulate an acrylic swivel ball 30 in an acrylic
template 20A without
creating a bond between the swivel ball 30 and the template 20A, such that
rotation of the
swivel ball 30 is readily possible. However, improved rotatability of the
swivel ball 30 may be
achieved by applying a bond-breaking or lubricating material (compatible with
the materials of
the template 20A and the swivel ball 30) to the interface between the template
20A and the
swivel ball 30 during the template fabrication process.
Although the template 20A is of laminar construction in the preferred
embodiment, as
described above, persons skilled in the art will readily appreciate that
alternative forms of
construction may be used for the template 20A without departing from the
concept of the
present invention, provided that the swivel ball 30 is mufti-axially rotatable
relative to the
template.
Disposed within the swivel ball 30 is a cylindrical guide tube 40, for
receiving a drill bit
(as will be explained in greater detail further on in this specification). The
guide tube 40
preferably projects from the swivel ball 30 so as to project through a guide
tube opening 26 in
the outer surface 23 of the template 20A. At least one dimension of the guide
tube opening 26
is larger than the width of the guide tube 40, so as to permit rotation of the
swivel ball 30 about
at least one axis. In the preferred embodiment, however, the guide tube
opening 26 is wider
than the guide tube 40 in all directions (and is preferably a substantially
circular opening), thus
permitting rotation of the swivel ball 30 about multiples axes.
To facilitate rotation of the swivel ball 30, the guide tube 40 may be
provided with a
handle 44 as conceptually illustrated in Figure 2. The handle 44 may be of any
configuration
that permits manipulation of the guide tube 40 and swivel ball 30.
Alternatively (or in addition
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to handle 44), the guide tube 40 may be fashioned with a tool slot 42 as
conceptually illustrated
in Figure 2. The tool slot 42 is adapted to receive a tool for manipulating
the guide tube 40 and
swivel ball 30 into a desired angular orientation.
In Figure 2 and other Figures, the guide tube 40 is shown passing completely
through
the swivel ball 30. As well in Figure 2, the inner layer 22 of template 20A is
shown as having
an opening in the area where the guide tube 40 passes through the swivel ball
30. However,
neither of these features is essential to the present invention. The guide
tube 40 need only
extend partially into the swivel ball 30, since the drill bit which will
ultimately be used in the
guide tube 40 will easily drill through any portion of the swivel ball 30 that
it may encounter.
Similarly, the drill bit will pass through the inner layer 22 of template 20A,
so an opening
through the inner layer 22 is not strictly necessary.
The Figures also show each swivel ball 30 configured with its guide tube 40 in
a
"vertical" position, but this is for convenience of illustration only. It will
be readily appreciated
that the angular orientation of the guide tube 40 is variable, in accordance
one of the
1 S fundamental principles of the invention.
The basic method of using the drill guide apparatus 10, as described above, is
easily
readily understood. Each guide tube 40 of the drill guide apparatus 10 can be
manipulated by
any convenient means (such as the handle 44, where provided, or an appropriate
tool engaging
the tool slot 42, where provided) to configure the guide tube 40 at a selected
angular orientation
for optimal alignment with the jawbone in which it is desired to drill an
implant socket through
the guide tube 40. Once the guide tube 40 has been positioned in a desired
angular orientation,
it can be fixed in position relative to the template 20A by application of a
suitable filler
material or bonding material around the guide tube 40 where it projects
through the guide tube
opening 26. With each guide tube 40 thus fixed in position, the drill guide
apparatus 10 may be
placed in the patient's mouth over the corresponding portion of the patient's
dentition,
whereupon a dental drill bit may be inserted through the guide tube 40 to
drill the desired
implant socket in the jawbone, with confidence that the axis of the resultant
socket will
substantially coincide with the pre-set angular orientation of the guide tube
40.
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In some cases it may be possible to drill a socket using a single surgical bur
or drill bit.
In other cases it may be necessary or desirable to drill the socket using a
series of two or more
drill sizes, by drilling a pilot hole with a small-diameter drill bit, and
then reaming out the pilot
hole with a larger bit, and perhaps reaming again with one or more progressing
larger bits.
This progressive drilling process is readily accommodated by the present
invention by inserting
appropriately sized sleeves (not shown) into the guide tube 40 for each bit
size being used.
Each sleeve would have an outside diameter slightly smaller than the inside
diameter of the
guide tube 40 (thus allowing for ready insertion and withdrawal into and out
of the guide tube
40 under close dimensional tolerances) and a concentric bore suitable for the
desired size of
drill bit. The use of such sleeves for sequential or multiple-bit drilling of
an implant socket will
ensure that the axis of the socket remains aligned with the axis of the guide
tube 40 at all stages
of the procedure.
Sleeves, if used, may optionally be fashioned with handles to facilitate
adjustment of
the swivel ball orientation. To facilitate the use of sleeves as described,
the guide tube 40 may
be fashioned with locking means to ensure that a sleeve inserted in the guide
tube 40 remains in
place within the guide tube 40 while implant sockets are being drilled in the
patient's j awbone.
Alternatively, this desirable condition can be achieved by fabricating the
sleeves to sufficiently
close tolerances for a press fit or friction fit inside the bore of the guide
tube 40.
In some cases, in addition to adjustment of the axial inclination of the guide
tube 40, it
may also be necessary or desirable to adjust the linear position of the guide
tube 40 in the
sagittal plane (i.e., mesio-distally) and/or cross-sectional plane (i.e.,
bucco-lingually). Such
adjustments are readily facilitated by alternative embodiments of drill guide
apparatus 10, as
described below.
In the embodiment shown in Figures 3, 4, and 4A (and in the similar
alternative
embodiment shown in Figures 5, 6, 6A, and 6B), an elongate swivel ball housing
50 (60) is
retainingly disposed within template 20B (20C) which has a guide tube opening
26. The
swivel ball housing 50 (60) has a central chamber enclosed by two opposing
sidewalk, each of
which has an inner face defining a concave, partially-cylindrical groove 52
(63) running
substantially the length of the sidewall. The grooves 52 (63) are
substantially parallel, and the
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radius of each groove 52 (63) corresponds to the radius of a swivel ball 30 as
previously
described. The swivel ball housing 50 (60) also defines a guide tube opening
51 (61) into the
central chamber, and the swivel ball housing 50 (60) is positioned in the
template 20B such that
guide tube opening 51 (61) is generally aligned with the guide tube opening 26
of the template
20B (20C). This construction of the drill guide apparatus 10 allows a swivel
ball 30 to be
disposed in the central chamber with its guide tube 40 projecting through
guide tube openings
26 and 51 (61), with the swivel ball 30 being laterally movable within grooves
52 (63) while
also being mufti-axially rotatable. Accordingly, both the lateral position and
angular
orientation of the guide tube 40, and therefore the implant socket ultimately
drilled through the
guide tube 40, can be readily adjusted.
In a simple method of using the invention, the guide tubes 40 can be oriented
into
desired positions by visual judgment only. As previously mentioned, however,
this method
entails a greater risk that the resultant implant sockets will be less than
ideal, if not totally
unsatisfactory and unusable. Accordingly, in the preferred embodiment of the
invention, each
guide tube is marked with a radiopaque material so that known radiologic
imaging methods can
be used to enhance the accuracy of the angular orientation and/or linear
position of the guide
tubes 40, in accordance with techniques well known in the art (and as
previously described
herein). Typically, the radiopaque marking on each guide tube 40 will be in
the form of one or
more straight lines aligned with the axis of the guide tube 40.
To facilitate or enable the use of radiologic imaging, the template 20 and
swivel ball 30
in the preferred embodiment of the invention are made from radio-transparent
material. X-rays
will pass through these components, such that when radiologic images are taken
of the patient's
jaw with the template 20 in place, the images will distinctly show the
radiopaque markings as
well as the jawbone in which implant sockets are to be drilled, so that the
locations and angular
orientation of the guide tubes 40 relative to the jawbone can be clearly
discerned.
Radiologic images thus facilitate precise determination of guide tube
manipulations that
may be required to optimize the linear location and angular orientation of the
sockets.
Preferably, in order to provide the oral surgeon with optimally precise
measurements needed
for three-dimensional adjustment of the drill guide apparatus at the time of
surgery, radiologic
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images are taken from at least two, thus enabling precise three-dimensional
imaging studies and
interpretations.
A particularly preferred imaging modality would include a CT scan / volumetric
scan,
such as using the NewTomTM 9000 volumetric scanner, with the drill guide
apparatus 10 in
S place in the patient's mouth. Axial, sagittal and cross-sectional views are
reformatted for
precise three-dimensional evaluation of the position of the drill guide
apparatus 10 relative to
the underlying alveolar process (i.e., jawbone structure), and evaluated by an
oral radiologist,
performing linear and angular measurements of the position of the drill guide
apparatus 10
relative to the underlying bone. In addition to the customary height and width
measurements of
the alveolar process, outlining vital structures such as the position of the
inferior alveolar nerve
canal in the mandible or the maxillary sinus in the maxilla, the most precise
and ideal
positioning of the proposed implantations with the help of the drill-guides as
seen on the scan,
should be determined.
The radiologist should be able to provide information regarding three-
dimensional
adjustment of the drill guide apparatus 10 by the surgeon in order to achieve
ideal fixture
placement. This would include modification of the position of the drill guide
apparatus 10 in
the mesio-distal and bucco-lingual dimensions, and modification of the angular
and axial
orientation of the drill guide apparatus. Working with true-size images, the
measurements and
adjustments provided should be true measurements. Using the apparatus of the
invention in
conjunction with precise three-dimensional evaluation methods (e.g., CT /
volumetric
scanning), it becomes possible to fashion both temporary and permanent
prostheses even before
the implant sockets are drilled in the patient's jawbone, with confidence that
the prostheses will
fit the patient. In this way, the present invention can significantly reduce
the total length of
time required for the dental implant procedure.
After an evaluation of the initial orientation of the drill guide apparatus
10, and it has
been determined that adjustments are desirable or necessary, it will commonly
be necessary to
transport the apparatus 10 to a dental laboratory where the required
adjustments are to be made,
and then transport the adjusted apparatus back to the dentist's or dental
surgeon's facility for
final radiologic imaging and ultimately for drilling of the implant sockets.
To ensure accurate
CA 02484475 2004-10-12
adjustment of the apparatus 10, it is important to ensure that the position of
the swivel ball 30
does not change during transport, either before or after adjustment. To
minimize or eliminate
the risk of movement of the swivel ball 30 during transport, the swivel ball
30 in preferred
embodiments of the invention will be provided with retention means for
maintaining the
angular position of the swivel ball 30 relative the template 20.
In a particularly preferred embodiment, the retention means may be provided in
the
form of a plurality of grooves or striations formed in the spherical outer
surface of the swivel
ball 30. The inventor has found that liquid acrylic material introduced
between the swivel ball
30 and the adjacent surfaces of the template 20 will flow into the grooves or
striations in the
swivel ball surface, thus forming a mechanical interlock with the swivel ball
30 while at the
same time bonding to the surfaces of the template 20. This has the effect of
fixing the position
of the swivel ball 30 relative to the template 20, thus allowing the apparatus
10 to be
transported for adjustment with confidence that the position of the swivel
ball 30 will not shift
in transit. The inventor has also found that the application of mild heat in
the vicinity of the
swivel ball 30 will make the acrylic material between the swivel ball 30 and
the template 20
sufficiently flowable so as to free the swivel ball 30 for adjustment. Upon
being returned to
ambient temperature the swivel ball 30 will once again be effectively fixed in
its adjusted
angular position within the template 20. Accordingly, the provision of grooves
or striations in
the swivel ball 30 facilitates retention of the swivel ball position both
before and after
adjustment. For greater certainty, additional acrylic or other suitable
bonding materials may be
applied to junctures between the swivel ball 30 and the template 20 after
final angular
adjustments have been made, so as to fix the swivel ball 30 even more securely
in its adjusted
orientation.
It will be readily seen by those skilled in the art that various modifications
of the present
invention may be devised without departing from the essential concept of the
invention, and all
such modifications are intended to be included in the scope of the claims
appended hereto.
In this patent document, the word "comprising" is used in its non-limiting
sense to mean
that items following that word are included, but items not specifically
mentioned are not
excluded. A reference to an element by the indefinite article "a" does not
exclude the possibility
16
CA 02484475 2004-10-12
that more than one of the element is present, unless the context clearly
requires that there be
one and only one such element.
17
