U.S. patent application number 15/233139 was filed with the patent office on 2017-07-13 for apparatus for evacuation of root canal.
The applicant listed for this patent is Ormco Corporation. Invention is credited to G. John Schoeffel.
Application Number | 20170196658 15/233139 |
Document ID | / |
Family ID | 35510236 |
Filed Date | 2017-07-13 |
United States Patent
Application |
20170196658 |
Kind Code |
A1 |
Schoeffel; G. John |
July 13, 2017 |
APPARATUS FOR EVACUATION OF ROOT CANAL
Abstract
In an endodontic procedure, after the working of a root canal by
instruments to remove material and shape the walls of the canal,
irrigant is supplied via a microcannula. A vacuum is applied via a
tube which is inserted partway down the root canal. The irrigant is
supplied in a manner sufficient to ensure delivery to a side vent
of the microcannula. The vacuum at the end of tube draws the
irrigant and debris up from the apex of the root canal into the
tube. The side vent may have a plurality of more round holes, a
diagonal slit, or a U shaped slit, or any other shape. The vent
opening should not extend more than approximately 0.75 mm from the
closed spherical tip of the microcannula, it must be burr free and
the opening must be smaller than the internal diameter of the
microcannula.
Inventors: |
Schoeffel; G. John; (Dana
Point, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ormco Corporation |
Orange |
CA |
US |
|
|
Family ID: |
35510236 |
Appl. No.: |
15/233139 |
Filed: |
August 10, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14281639 |
May 19, 2014 |
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15233139 |
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13274336 |
Oct 16, 2011 |
8827705 |
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14281639 |
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11629552 |
Dec 13, 2006 |
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PCT/US05/21039 |
Jun 14, 2005 |
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13274336 |
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11152942 |
Jun 13, 2005 |
7226288 |
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11629552 |
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10387804 |
Mar 13, 2003 |
6997714 |
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11152942 |
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60579915 |
Jun 14, 2004 |
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60579915 |
Jun 14, 2004 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61C 5/50 20170201; A61C
17/08 20190501; A61C 5/40 20170201; A61C 17/0208 20130101 |
International
Class: |
A61C 5/40 20060101
A61C005/40; A61C 17/02 20060101 A61C017/02; A61C 17/06 20060101
A61C017/06; A61C 5/50 20060101 A61C005/50 |
Claims
1.-7. (canceled)
8. A method for evacuating a root canal of a tooth, said tooth
having a coronal end with an open access cavity and an apex end,
the method comprising: delivering a fluid into said root canal at
said coronal end of said tooth; inserting a cannula into said root
canal such that a tip of said cannula is located in an apical third
of said root canal; and evacuating said fluid from said root canal
through said cannula to cause fluid flow in a direction from said
coronal end toward said apex end.
9. The method of claim 8 wherein inserting said cannula positions
said tip of said cannula in an apical portion of the root
canal.
10. The method of claim 8 wherein inserting said cannula positions
said tip of said cannula within 5 mm of the apex end.
11. The method of claim 8 wherein, prior to inserting the cannula
into said root canal, the method further comprises: inserting a
second cannula larger in diameter than said cannula into said root
canal nearer said coronal end of said tooth than said cannula; and
evacuating said fluid from said tooth through said second
cannula.
12. The method of claim 11 further comprising: evacuating said
fluid from said coronal end of said tooth during evacuating said
fluid from said root canal through said cannula.
13. The method of claim 8 further comprising: evacuating said fluid
from said coronal end of said tooth during evacuating said fluid
from said root canal through said cannula.
14. The method of claim 8 wherein inserting said cannula includes
inserting said tip of said cannula through an apical foramen of
said root canal and then withdrawing said tip of said cannula to a
position in said root canal at which evacuating said fluid from
said root canal through said cannula starts.
15. The method of claim 8 wherein evacuating said fluid through
said cannula includes evacuating said fluid through one or more
openings that are positioned around the circumference of said
cannula.
16. The method of claim 15 wherein said one or more openings are
each smaller than the internal diameter of said cannula.
17. The method of claim 8 further comprising: providing a source of
vacuum at said open access cavity for evacuating said fluid from
said coronal end of said tooth.
18. A method for evacuating a root canal of a tooth, said tooth
having a coronal end with an open access cavity and an apex end,
the method comprising: supplying a fluid to said root canal;
inserting a cannula into said root canal; and evacuating said fluid
from said root canal to cause fluid flow near an apical third of
said root canal.
19. The method of claim 18 wherein evacuating said fluid causes
fluid flow near an apical portion of said root canal.
20. The method of claim 18 wherein inserting said cannula includes
positioning a tip of said cannula near an apical portion of said
root canal.
21. The method of claim 18 wherein evacuating said fluid evacuates
fluid through said cannula.
22. The method of claim 18 wherein supplying said fluid includes
delivering said fluid at said coronal end of said tooth.
23. The method of claim 18 wherein, prior to inserting the cannula
into said root canal, the method further comprises: inserting a
second cannula larger in diameter than said cannula into said root
canal nearer said coronal end of said tooth than said cannula; and
evacuating said fluid from said tooth through said second cannula.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S.
application Ser. No. 14/281,639 filed May 19, 2014, which is a
continuation of U.S. application Ser. No. 13/274,336 filed Oct. 16,
2011, which is a continuation of U.S. application Ser. No.
11/629,552 filed Dec. 13, 2006, which is a National Stage Entry
under 35 U.S.C. .sctn.371 of PCT/US05/021039 filed Jun. 14, 2005,
which claims priority to U.S. application Ser. No. 11/152,942 filed
Jun. 13, 2005, and U.S. Provisional Patent Application Ser. No.
60/579,915 filed Jun. 14, 2004, and U.S. application Ser. No.
11/152,942 is a continuation-in-part of U.S. application Ser. No.
10/387,804 filed Mar. 13, 2003 and also claims priority to U.S.
Provisional Patent Application Ser. No. 60/579,915, the disclosures
of which are incorporated by reference herein in their
entireties.
TECHNICAL FIELD
[0002] The invention is in the field of endodontics, more
particularly methods and apparatus used during root canal
procedures.
BACKGROUND
[0003] To preserve a tooth that has or could develop a diseased
pulp cavity, it is necessary to prevent bacterial proliferation
within the root or pulp canal of the tooth by enlarging the canal
without excessively weakening the root's wall by using endodontic
files, bores, reamers or other instrumentation in order to: 1)
mechanically remove as much of the root canal contents as is
possible and 2) allow the introduction of irrigants into the root
canal space that dissolve and disinfect organic debris, thus
minimizing the presence of bacteria, as well as clearing the walls
of the root canal of calcific debris created during
instrumentation. After completing steps 1 and 2, the root canal is
typically filled or obturated with a material such as gutta-percha
and a sealer to occlude the pulp cavity and thus seal the root
canal. This procedure is referred to as root canal therapy.
Irrigation assists in removing debris and necrotic material
remaining after the endodontic files, bores, and reamers used
during the removing and shaping steps of the procedure. Although,
the irrigant preferably is capable of dissolving or disrupting soft
tissue remnants to permit their removal, the irrigant may be any
suitable liquid such as water or various alcohols. More
particularly, although some degree of debridement is preferred, any
fluid may be used to flush debris from the root canal. General
examples of appropriate irrigants include hydrogen peroxide and
sodium hypochlorite. In order to ensure that as much of the debris
and necrotic material as possible is removed, the irrigant is
typically applied under pressure using a syringe and a needle
inserted into the canal as shown in FIGS. 2A and 2B. However, as
reported in Endodontics, 5th Edition, by John I. Ingle and Leif K.
Bakland published June 2002, pages 502-503, it is important that
the needle fit loosely in the canal to allow backflow. It is also
reported that there is little flushing beyond the depth of the
needle unless the needle is bound in the canal and the irrigant
forcibly ejected, which is undesirable due to the danger of an
irrigant such as sodium hypochlorite breaching the apex of the
canal and entering the periapical tissue. However, unless the end
of the needle is near the apex, the portion of the canal from the
apex to the end of the needle cannot be effectively irrigated. But
placing the end of the needle near the apex increases the
likelihood of the irrigant, which is applied under pressure,
entering the periapical tissue. This can be a source of post
treatment endodontic pain for the patient. Furthermore, if a
significant quantity of an irrigant like sodium hypochlorite is
accidentally injected into the periapical tissue, morbid clinical
complication can occur including excruciating pain, immediate
swelling (ballooning) of the tissue, and profuse bleeding.
[0004] Existing techniques attempt to address this problem by using
very small needles to get close to the apex while still fitting
loosely in the canal to allow backflow or using an instrument to
move some of the irrigant towards the apex with the irrigant no
longer under pressure. However, neither technique completely solves
the problem. Even the tip of the smallest needles that deliver
irrigants under pressure must be kept a safe distance
(approximately 4-6 mm) away from the apex in order to avoid
accidentally forcing irrigants into the periapical tissue. This
safety issue most often results in an area or zone between the apex
and needle tip devoid of irrigant. Use of an instrument to force
the irrigant through this zone towards the apex is very time
consuming and also does not guarantee that the irrigant has flushed
the canal all the way to the apex without going too far.
SUMMARY OF THE INVENTION
[0005] The present invention addresses the prior art problems of
inadequate delivery of the irrigant to the apex of the canal
resulting in an incomplete cleaning of the canal and penetration of
the irrigant past the apex into the periapical tissue resulting in
treatment complications. According to the invention, after the
working of the canal by instruments to remove material and shape
the walls of the canal, a cannula is inserted into the canal
extending to about 5 mm from the apex and a vacuum is applied which
begins to suck up the debris inside the canal. As this vacuum is
applied, a small tube used to deliver irrigant is placed just
inside the coronal opening of the root canal. Irrigant is passively
flowed into the opening of the root canal, but not under pressure.
As the irrigant is supplied, it is drawn to the source of the
vacuum causing it to cascade down the walls of the root canals,
into the tip of the cannula and out through the vacuum system.
After several minutes of irrigant cascading down the canal walls,
the cannula is removed and a second, smaller cannula with a hole in
its wall near the tip is inserted into the canal until it virtually
touches the apical tissue, but unlike the prior art, extending it
past the apex does not cause irrigant to enter the periapical
tissue because as soon as the hole enters the periapical tissue,
since it is no longer in an open space, the vacuum created by the
cannula is not present. In an alternate embodiment, instead of
delivering irrigant via the cannula and applying a vacuum to the
microcannula, the irrigant may be supplied via the microcannula. In
this embodiment, a vacuum is applied via a tube which is inserted
partway down the root canal. Tube and microcannula pass through a
material created by a standard dental filling material of a
composite nature which provides a seal at a position near the top
of the coronal opening. The irrigant is supplied in a manner
sufficient to ensure delivery to the side vent of the microcannula.
The vacuum at the end of tube draws the irrigant and debris up from
the apex of the root canal into the tube.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a cut away side view of a tooth showing its root
canal and periapical tissue.
[0007] FIGS. 2A and 2B show a prior art endodontic irrigation
system.
[0008] FIG. 3A is a cut away side view of a tooth showing a first
cannula and fluid delivery tube.
[0009] FIG. 3B is an expanded view taken along line 3b-3b of FIG.
3A.
[0010] FIG. 4A is a cut away side view of a tooth showing a second
cannula and fluid delivery tube.
[0011] FIG. 4B is an expanded view taken along line 4b-4b of FIG.
4A.
[0012] FIG. 5 is a cut away side view of a tooth showing an
alternate embodiment of the invention illustrated in FIG. 4A.
[0013] FIGS. 6A-6E show alternates embodiments of the side vent
used by microcannula 41.
[0014] FIG. 7 shows a finger piece for use with the invention.
[0015] FIG. 8 shows how the finger piece of FIG. 7 is used.
[0016] FIG. 9 shows a master delivery tip with syringe for use with
the invention.
[0017] FIG. 10 shows how the master delivery tip of FIG. 9 is
used.
[0018] FIGS. 11A and 11B show the detail of a macro cannula or
cannula for use with the invention.
[0019] FIG. 12 shows a handle which may be used to hold the macro
cannula shown in FIGS. 11A-11B.
DETAILED DESCRIPTION
[0020] FIG. 1 illustrates a cutaway portion of a human tooth 11 as
it may appear after a portion of a root canal procedure has been
completed, namely wherein as much of the pulp material as is
possible has been removed by instrumentation. The tooth 11 includes
a crown portion 13 which is generally the exterior portion
extending past gums 15. The interior portion of the tooth extending
past the other side of gums 15 is referred to as the root 17. In
approximately the middle of the root extending almost the entire
length of the root is the root canal 19 which extends from one end
21 near the crown portion of the tooth to an apex 23 at the tip of
root 17. As shown in FIG. 1, the non-visible portion of tooth 11
extending past gums 15 is surrounded by periapical tissue 25.
[0021] Of course, prior to the initiation of the root canal
procedure, the apical foramen 27 located at or very near the root
apex 23 is the only opening into the root canal.
[0022] After the instrumentation phase of the root canal procedure
has been completed, there is a large quantity, both in terms of
size and amount, of debris within the root canal.
[0023] According to the present invention, after the
instrumentation step, cleansing of the root canal is performed in
two phases. The first phase is referred to as gross evacuation of
the coronal portion of the root canal which is the portion of the
root canal 19 beginning approximately 4-5 mm from apex 23. The
second phase is referred to as apical evacuation for cleaning the
final 4-5 mm of the root canal.
[0024] Referring now to FIG. 3A, the methods and apparatus used for
the gross evacuation of the coronal portion of the root canal will
now be explained. A cannula 31 is inserted into the canal to a
point 33 approximately 4-5 mm from the apex as seen in FIG. 3B. A
suitable cannula for this purpose is a soft plastic cannula such as
part number UP0341 available from Ultradent Products, Incorporated
located in South Jordan, Utah. Of course, any comparable device may
be used for this purpose. A vacuum is applied to the cannula as is
well known in the art which results in debris being sucked up into
the cannula. Specifics of a suitable delivery tube 35 and vacuum
system are well known to persons skilled in the art.
[0025] A fluid delivery tube 35 is placed at the top of the coronal
opening of the root canal at end 21 as shown in FIG. 3A and the
desired irrigant is supplied by fluid delivery tube 35. A suction
exists at point 33 of the cannula by virtue of an opening in the
end of the tube adjacent to point 33 and the applied vacuum which
results in the irrigant and remaining debris being drawn to the
hole in the end of cannula at point 33. This irrigation and suction
results in a nearly complete cleaning of the upper portion of the
canal, i.e., the portion extending from the tip of the cannula at
point 33 through the entire length of the canal to end 21. This
occurs because as the irrigant is delivered via the delivery tube,
the irrigant fills the root canal space combines with the debris
and together are sucked down the root canal by virtue of the vacuum
created at the end of delivery tube at point 33 and then up through
cannula 31 by virtue of the vacuum created. This step normally
takes several minutes to complete depending on the size of the root
canal space. For example upper canine teeth have larger root canal
spaces than lower incisors and require a longer initial irrigation.
At the end of this phase the irrigant will be clear and devoid of
gas bubbles formed by the dissolving necrotic tissue as well as
particulate matter remaining from instrumentation.
[0026] It should be noted that although some irrigant may go past
end 33, the 4-5 mm distance from apex 23 is sufficient to prevent
any irrigant from reaching periapical tissue 25.
[0027] The gross evacuation of the canal debris in the upper
portion of the root canal is critical to the proper completion of
phase two since a much smaller tube is used to evacuate the apical
portion, i.e., the bottom 4-5 mm of the root canal. This is because
the debris in the upper portion of the root canal, prior to the
evacuation performed by phase one, includes particles of a size
which would clog the smaller opening of the microcannula which is
inserted into the apical portion of the root canal.
[0028] Phase two of the procedure will now be described with
references to FIGS. 4A and 4B. In phase two, a microcannula 41 is
inserted into the root canal extending to the apex 23 as best seen
in FIG. 4b. Microcannula 41 is typically made of a metallic
material such as stainless steel or titanium and in one embodiment,
has an outside diameter of 0.014 inches. Its tip 43 is welded shut
and rounded and includes a side vent approximately 0.75 mm long
beginning at a point approximately 0.5 mm from the end of tip
43.
[0029] Of course, the foregoing dimensions and materials are
provided by way of example of a specific embodiment. What is
important is that microcannula 41 be sized so as to be able to fit
into the canal so that it extends substantially completely to apex
23 with side vent 45 extending as close to the end of the root as
possible but without extending into the periapical tissue. Further,
microcannula 41 should be sized so that there is close contact
between the root canal wall in the apical portion and the
microcannula. This is to ensure that some of the irrigant is drawn
to the end of microcannula 41 by capillary action.
[0030] As was the case in phase one, irrigant is delivered via
delivery tube 35 and a vacuum is applied to microcannula 41. In
this manner, irrigant is drawn down into the root canal and into
the apical portion of the root canal, that is, the bottom
approximately 4-5 mm portion of the canal ending at apex 43. Since
tip 43 is closed, irrigant is drawn into vent 45 and does not
extend past tip 43 and cannot be drawn into apical tissue 25 due to
the vacuum which exists at vent 45. By this technique, the irrigant
flushes the apical portion of the root canal, removing out any
remnants of debris which still exist in a manner which does not
allow the irrigant to enter the periapical tissue.
[0031] Additionally, and importantly, in the event microcannula 41
is accidentally forced into the periapical tissue, the side vent
will become obstructed by the tissue and the vacuum which exists in
the root canal ceases to exist. Since the irrigant in the canal is
not under pressure, the irrigant will cease to be withdrawn by
microcannula 41 indicating to the practitioner that the
microcannula has extended too far and needs to be withdrawn back
into the root canal space slightly, up to the point when the side
vent is not in the periapical tissue at which point the irrigant
again begins to be withdrawn.
[0032] In an alternate embodiment, and referring now the FIG. 5,
instead of delivering irrigant via delivery tube 35 and applying a
vacuum to microcannula 41, the irrigant may be supplied via the
microcannula. In this embodiment, a vacuum is applied via a tube 51
which is inserted partway down the root canal. Tube 51 and
microcannula 41 pass through a material created by a standard
dental filling material of a composite nature (like the material
used in white dental fillings) or alternately a standard dental
impression material usually made of a silicone nature which
provides a seal at a position near the top of the coronal opening.
The irrigant is supplied in a manner sufficient to ensure delivery
to the side vent 45 of the microcannula. The vacuum at the end of
tube 51 draws the irrigant and debris up from the apex of the root
canal into the tube.
[0033] In this alternate embodiment, the flow of the irrigant may
be reversed from apex to crown by placing the microcannula adjacent
to the apex, installing a vacuum tube into the canal near the
coronal portion and sealing the canal coronally such that both and
microcannula and vacuum tube are below the seal, with the vacuum
tube being positioned more coronally. As a vacuum is applied to the
coronal tube, irrigant is allowed to be drawn into the canal via
the microcannula, then up the walls into the vacuum tube.
[0034] Referring now to FIGS. 6A-6E, side vent 45 instead of having
a generally oblong shape as shown in FIG. 4B, may have a plurality
of more round holes as shown in FIGS. 6B and 6C, a diagonal slit as
shown in FIG. 6D or a U shaped slit as shown in FIG. 6E, or any
other shape. In the FIG. 6B embodiment, the holes actually extend
around the circumference of the microcannula. The diameter of the
microcannula is 0.318 mm and the distance between the tip of the
microcannula and the bottom of the hole nearest the tip is 0.22 mm.
In one embodiment, the opening should not extend more than
approximately 0.75 mm from the closed spherical tip of the
microcannula, must be burr free and the opening must be smaller
than the internal diameter of the microcannula to block any
particles which clog the microcannula. The reasons the openings
must be burr free is that the space where the microcannula is
inserted is extremely restricted, and any burr extending from the
opening is likely to scrape the dentin from the wall of the root
canal and the resulting debris could clog the side vent opening(s).
Usually, microcannula 41 is coupled directly to a tube used to
provide the vacuum or supply the fluid.
[0035] FIG. 7 shows a finger grip handle 71 used to hold
microcannula 41 (shown in shadow line). The finger grip handle has
an opening 73 into which microcannula 41 is inserted. A second
opening 75 arranged 90.degree. from opening 73 receives a tube
(shown in shadow line) which is connected to a device which
produces the required vacuum or supplies the required fluid. Ridges
79 provide a grip to assist holding the handle between two fingers
as shown in FIG. 8. Given the relatively small dimensions of
microcannula 41 and the difficulty of maneuvering the microcannula
within the confines of the mouth to perform the desired procedure,
finger grip handle 71 provides extra leverage not available without
the handle. In a preferred embodiment, finger grip handle is made
of titanium. The two openings are sized to so that the microcannula
and vacuum or fluid delivery device are held by friction.
[0036] FIG. 9 shows a master delivery tip. The delivery tip
includes a metal tube 91 set into a molded fixture made of
non-reactive plastic like nylon or polypropylene that is inserted
on a standard luer lock fitting. The molded fixture holds a
flexible plastic tube 93 non-reactive plastic like PVC over the
metal tube, the other end being attached to a vacuum pump (not
shown). During clinical use the clinician is able to add a fluid
into the access cavity preparation of a root canal. When the level
of the fluid being applied tube 91 reaches the top of the access
cavity preparation, the excess is sucked away by a vacuum applied
to tube 93 rather than spilling into the oral cavity (mouth). This
feature allows the dentist or dental assistant to maintain a
constant level of fluid in the root canal access cavity and is
helpful throughout all aspects of root canal preparation including
instrumentation and irrigation. FIG. 10 shows this operation
wherein the fluid being applied is concurrently sucked away.
[0037] FIG. 11A shows a specific design of a cannula 95 which may
be used as cannula 31. A top portion 99 which is 5.0 mm in length
has a slight taper for fitting into an opening in a handle 97 shown
in shadow line in FIG. 11A and in more detail in FIG. 11B. A middle
portion 101 which is 7.5 mm in length tapers to an outside
dimension of 1 mm. A third portion 103 tapers from 1 mm to 0.55 mm
at its end. The inside dimension at this end is 0.36 mm. While it
is preferable that there be no flash at the end of the third
portion, there is a 5% of inside diameter surface area maximum
flash permitted at this point, since anything larger would serve to
trap canal debris.
[0038] FIG. 12 shows handle 97 having head 105 sized to fit the top
end of cannula 95 (or microcannula cannula 41 or 31) by friction.
Raised elements 107 provide a finger grip. The opposite end 109 of
handle 106 is sized to accept a tube from a vacuum unit (not
shown).
* * * * *