Note: Descriptions are shown in the official language in which they were submitted.
This invention relates to an interdental immobilization
device.
From time to time, it is necessary to immobilize the
human jaw.
This will be necessary when fractures of mandible occur
or when (sparingly) one wishes to have their mouth fixed shut
so as to avoid eating, and hence losè weight.
The existing method of the prior art uses a pliable
metal strip with projecting hooks known as an archbar and
several fine wires and rubber bands. The metal strip is
secured tightly to the teeth of the upper jaw by passing a
wire around the base of a tooth and through the gum and over
each side of the tooth and also over the metal strip. At this
point both ends of the wire are outside the mouth and are
twisted together to hold the metal strip urgingly against the
outside surEace of the teeth. The twisted wire is then cut to
a length of approximately 1/8 to 1/4 inch and bent backward
towards the gum and preferably placed in between two adjacent
teeth to prevent irritation on the inside of the lips.
This is repeated spatially around eight to twelve teeth
of the upper ]aw and the same is repeated over the lower jaw.
The metal strip has the projecting hooks spatially
disposed on its outside surface and over these hooks small
rubber bands or wires are then attached between those hooks of
the meta] strip attached to the teeth of the lower jaw and
those hooks oE the upper jaw. This techni~ue has been
published at pages 301 through 303 in Surgery of the Upper
Respiratory System (Vol 1-2nd Edition) by William W.
Montgomery M.D., Published by Lea & Febiger, Copyright 1~79.
This particular prior art technique, which is extremely
common in North America, and around the world has several
disadvantages. The most dominant disadavantage is that during
twist tightening of the wires, the wires can easily snap and
the whole process must be repeated hence adding to the length
of the installation procedure. It is not uncommon for this
- procedure to take between 1 and 2 hours of operating theatre
time since a general anesthetic for the patient is always
needed.
~2~ 66
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After approximately two days of use, the wires need to
be retightened and retwisted as they have a tendency to loosen
ofE and sometimes break. If they break during tightening, th0
patient must be re-anesthetized again within the operating
theatre and new wires inserted as before. Further, the
patient must be anesthetized for wire removal after the jaw
has mended.
With the recent scare of AIDS and HEPATITIS B, there is
a constant danger of trauma to the surgeons hands from the
ends of the wire and hence exposure to the patient's body
fluids and blood since the passing of the wire between the
teeth, always ruptures the gum and the gum bleeds.
We have conceived of a fixture which can be placed and
bolted between the teeth. The fixture exposes an anchoring
surface, which preferably is cylindrical, onto which the
rubber bands or wires may be attached so as to fix the lower
and upper jaw into rigid position.
The fixture according to the invention has several
advantages over the prior art; namely,
(a) anesthetic is generally required only on the
installation of the fixture;
(b) the fixture may be tightened by the simple
expedient of turning down a nut on a screw as there is
no wire and -therefore wire twisting with the appendant
possibility of wire breakage cannot occur; thus, the
step for re-installation of possibly broken wires in an
operating theatre environment with the patient
anesthetized is avoided; and,
~c) the fi~ture is easily removed generally without the
patient being re-anesthetized.
The invention, in its preferred embodiment, contempla-tes
; -therefore; a truncated cone, a screw, and a nut; the nut and
cone defining a screw accommodating channel. The channel
through the truncated cone extends from the flat bottom of the
cone through the apex and the cone preferably is a near
upright conic. The screw has a threaded shaft while the nut a
channel that threadingly mates with the shaft.
~ :25~1~66
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; In yet a further alternative embodiment of the invention
two cones rather than one cone may be used.
In one variant of the nut, the internal diameter of the
channel is smooth bored and slightly smaller in diameter than
that of the threaded shaft. In the preferred embodiment of
this variant, the nut is composed of a plastic material such
as nylon and has a shorter major bore diameter larger than
that of the screw that steps into a longer minor bore with
diameter slightly smaller than that of the threaded shaft.
The length of the minor bore is substantially greater than
that of the major bore. In an alternative embodiment of the
- nut, the nut has a helically threaded channel of constant
diameter which threadingly mates with the screw and in this
embodiment the nut is preferably composed of a metal such as
stainless steel.
In yet a urther embodiment of the threaded shaEt, the
shaft has means to index itself into one o the cones as well
as to protrude beyond the cone as a bent tip so when fixed
between the teeth the bent tip stands as a protrusion in ~he
crevice deEined by these adjacent teeth.
The invention therefore contemplates a fixture Eor
interdental immobilization comprising:
(a) an interconnecting engagement member with
engagement means;
(b) a first and a second anchor member adapted to be
spatially disposed and fixedly attached to the
engagement member;
(c) a capture region; and,
(d) means for adjustably locating said anchor members
relative to each other and for carrying the capture
region, the capture region baing adapted to carry
selected interconnecting elements to interconnect said
fixture with a second such fixture relatively disposed
at a pre-determined distance.
Particularly, in its preferred embodiment the fixture
comprises:
1 259 8~D6
(a) an elongated screw member carrying a first anchor
means and having an attachment means;
(b) a second anchor means;
~c) a capture region;
(d) locating means for fixedly locating said second
anchor means along said longitudinal member at a
pre-determined spatial position and for locating the
capture region thereon.
More specifically, there i5 an "L" shaped screw with a
distal arm and a threaded shaft and a pointed tip thereon a
proximate arm wherein the proximate arm extends through an
obtuse angle into a straight inclined piece that acts as a
protrusion. This screw protrudes through an anchor member
which in one embodiment is a truncated cone~ The screw and
cone are stainless steel in the preferred embodiment while the
second anchor means, in the preferred embodiment includes a
capture region and is composed of nylon with a smaller major
bore stepping into a smaller minor bore si~ed a diameter
smaller than that of the screw so that the screw can tap into
the minor bore a helical thread for matingly securing the nut
onto the screw. The screw also carries a capture region which
in its preferred embodiment i5 a circumferential shoulder
which acts as a bearing surface for interjoining a plurality
of said fixtures located spatially between teeth of the upper
and lower jaw.
The invention wil~ now be described by way of example
and reference to the accompanying drawings in which:
Figure 1 is a perspective assemb-y view of the preferred
embodiment of the invention.
Figure 2 is a perspective assembly view of an
alternative embodiment of the invention.
Figure 3 is a section through the embodiment according
to figure 1 showing its implantation adjacent a tooth shown in
phantom;
(a) figure 3A is a partial section of a longer screw in
the nut of figure 3 showing how the screw distal end is
severed after implantation.
Figure 4 is a perspective view of the Eirst step
according to the prior art.
Figure 5 is a plan view of the brace according to the
prior art secured by wire to teeth.
Figure 6 illustrates the securing of the upper and lower
jaw according to the prior art.
Figure 7 corresponds to figure 4 as it relates to the
implantation of devices according to the invention.
Figure 8 is a perspective view showing the implantation
of the preferred embodiment of the invention between teeth as
viewed from the inside of the mouth and hence is a view along
VIII-VIII of ~igure 7.
~igure 9 is a partial perspective view of a jaw
indicating the mode of securing the upper and lower jaws
according to the invention.
Figure 10 is cross-sectional view of one embodiment of
the nut.
Figure 11 is a cross-sectional view of another
embodiment of nut according to the invention.
Referring to figure 1, the fixture 10, according to the
invention, consists of a U shaped screw member 11 with an
upstanding proximate arm 12 that is bent through an obtuse
angle 12' to terminate as a forwardly inclined straight piece
12". The screw member 11 carries a longitudinal shaf-t 13 with
its distal end tapering to a point at 14. Part of the shaf-t
13 is helically threaded as a~ 15. A truncated conic member,
or cone 16 consists of a flat bottom 19 through which extends
a slot 20 and the cone defines therethrough a channel 18 which
- passes through the apex oE the cone and hence truncates it as
shown in figures 1 and 2. The channel 18 is a diameter
slightly larger than the diameter of the shaft 13 so as to
allow free passage therethrough. This is more clearly seen in
the sectional figure 3. The slot 20 is outwardly tapered at
20' at the identical obtuse angle as at 12' so that the
proximate arm 12 may appropriately index within the slot 20
and the bend 12' and straight distal piece 12" mate against
the inclined or beveled surface of slot 20' allowing the end
-- 6 --
of the distal piece 12' to protrude into the crevice defined
by the bodies of two adjacent teeth.
The nut 17 in one of the preferred embodiments, that is
shown in figures 1 and 10, is formed of nylon and the channel
21 is a stepped smooth walled channel, as more clearly seen in
figure 10, with a shorter major bore 21C and a longer minor
bore 21CR; the major bore interfacing with the apex thereof.
Also, the nut 17 may be profiled as seen in figures 1 and 3 so
as to provide an outter hexagonal gripping surface 22H sized
greater than the diameter of the cylindrical shoulder 23
through which it steps into a truncated conical section 24.
The face of the nut obverse to the truncated conic 24 is
conically recessed at 25 as more clearl~ seen in figure 3 (see
also figures 10 and 11). If the tip 14 of the screw 13
extends into the conical recess 25 aEter the physician has
placed the fixture 10 between teeth, as will be disclosed
hereafter, the physician has room to insert a pair of diagonal
cutters 30 (see figure 3A) or the like into the recess 25 and
to snip off the protruding segment of shaft 13 and the tip 14
which are collectively shown as SR so as not to cause abrasion
to the inner skin of the mouth.
Referring to figures 3 and 8, in application, the screw
11 is fitted to slip through cone 16 with the proximate arm 12
indexing into the slot 20. The screw 11 is pushed between the
base of two adjacent teeth 50 (502 and 503 in figure 8) and
the point 14 assists in the penetration of the screw 11 from
the inside of the mouth through the gum mass between said
teeth 502 and 503 to the outside gum surface. The nut 17 is
then, if hexagonally formed as in figure 1, put into a socket
wrench and threaded onto the screw 11 so as to urge against
the adjacent teeth 502 and 503 as well as the adjacent gum
mass. If the profiled nut of figure 1 having the hexagonal
surface 22H is nylon, and has the stepped ~ore channel, shown
in figure 10, the tapered tip 14 of the screw 11 indexes into
the opening face of the major channel 21C and as the nut is
rotated, the screw 11 itself taps a helical thread into the
wall of the minor bore 21CR of the nylon nut of figures 1, 3
. .
and 10 and secure anchoring is thereby acheived. As the nut
17 is turned tighter, the cone 16 and the conic section 24 of
the nut 17 are drawn toward each other and a tight fit is
acheived. If there be any loosening off at a later time it is
simple to just slightly turn down the nut with the socket
wrench.
This step is repeated to locate, as shown in figure 71 a
plurality of fixtures 10 mounted between teeth along the lower
jaw. The steps are repeated in relation to the upper jaw.
The shoulder cylindrical surface 23 of the nut 17 is
used as the capture region for anchoring wire W, which is
laced between top and bottom fixtures as shown in figure 9.
In this way, the lower jaw is immobilized to the upper jaw.
This wrapping may just be accommodated by weaving or
wrapping of wire W or if preferred, elastic loops Wl may be
used.
Referring to figure 2, a further alterna-tive embodiment
consists of two identical truncated stainless steel conics
shown as 16' and 16". The screw 11 has but a proximate
straight arm 12 and that arm indexes into the slot ~0 of the
truncated conic 16'. The nut 17 is fashioned without a
tapered conic section 24 and hence a flat bearing as shown and
for reason, a second conic 16" identical to that of 16' is
used as the bearing member for the nut. Similarly, as
disclosed relative to ~igure 1, the screw 11, the conics 16'
and 16" and nut 17 may be installed between the teeth. This
particular embodiment is less favourable to that of figures 1
and 10 since there are 4 rather than 3 discreet components to
the fixture 10 and the nut is stainless steel as that of
figure 11 but profiled as in figure 2 without the conic
surface 24.
Referring to figure 3A the length of the screw 11 may be
structured quite long so as to accommodate various depths
(thicknesses of teeth). In that instance, the tip 14 of the
screw 11 protrudes well beyond the face of the conical recess
25 of the nut as shown in figures 3 and 3A. This overhang
extent SR may be cut off with a pair of wire cutters 30 as
9~;16~
-- 8 --
shown in figure 3A. This provides means for reducing the
length of the screw each time that the nut 17 is turned down
on the teeth to tighten the fixture. Abrasion to the inner
lip and cheek is thus avoided~
Returning now to figure 10, when the nut is composed of
nylon, the channel may be a two step bore as shown that is a
shorter major bore ?1C that steps into a longer ~inor bore 21
CR. The thread 15 of the screw 11 may be modified (though not
required) near its tip 14 with a cup at 14C and a protruding
piece 14I which ~ooperatively act as a "tap". When the nylon
nut 10 is turned down on this end taped threaded shaft of the
screw 11' the screw 11' self taps the minor bore 2lCR -to form
a mating thread therein securing the nut 17 thereon.
In the preferred embodiment of figures 1, 3, and 10, the
screw 11, and cone 16, are s-tainless steel and the nut 17 is
made of nylon. We have found that a cone base diameter of
approximately 5 m.m. and a cone height of 3 m.m. is
satisfactory with an angle of 40. This means that the
hexagon diameter 22H of the nut 17 is preferrably about 7
m.m. while the shoulder portion 23 diameter is about 5 m.m.
~ith a depth of shoulder of about 2 m.m~ to allow adequate
space for winding of wire or elastics Wl between respective
shoulders of fixtures in a manner as seen in figure 9. In
this respect the preEerred length of the screw is about 12
m.m. with the screw arm 12 having a length of approximately
2.5 m.m. and protrusion 12l' of about 2.5 m.m. and an outside
bend diameter at 12' of 0.8 m.m. In this respect, slot 20 cut
into the face of the base of the cone has a preferred depth of
approximately 1 m.m. and a preferred width of between 0.8 and
1 m.m.
In a variant of the nut 17, it may be stainless steel as
shown in figures 1 and 11. In this instance, the central
channel 21 is a uniform helically threaded channel 21N shown
in figure 10. The stainless steel nut may be profiled with
either the hexagonal surface 22H of figure 1 or with a
cylindrical knurled surface 22N and of figure 2,
It should be noted, that if the formed screw 11 of
figure 1 is used, the proximate arm tip of the straight piece
12" protrudes beyond the conic 16 (as shown in figure 3) into
the crevice defined by the bodies of two adjacent teeth (see
figure ~) and anchors the screw preventing its rotation and
the corresponding rotation of the conic 16 in figures 1, 3,
and 8, as the nut 17 is initially turned down. If the screw
11 is of the unmodified shape, as shown in figure 2, the screw
11 and the conic 16' of that finger is a tendency that they
rotate on the initial turning down of the nut 17 irrespective
of which profile 22H or 22N the nut has. This empediment is
amplified when the step bore nylon nut of figure 10 is used on
the screw 11 of figure 2 or figure 10, while if the stainless
steel nut 17 of figure 11 is used i.e., having a uniform
threaded channel 21~ the problem is less pronounced.
