U.S. patent number RE44,917 [Application Number 13/722,653] was granted by the patent office on 2014-05-27 for compositions, kits and methods for initiating or accelerating curing of endodontic filler or sealer compositions placed on a root canal.
This patent grant is currently assigned to Ultradent Products, Inc.. The grantee listed for this patent is Ultradent Products, Inc.. Invention is credited to Jaleena Fischer-Jessop, Neil T. Jessop, Richard D. Tuttle, Jeff A. Wagner.
United States Patent |
RE44,917 |
Tuttle , et al. |
May 27, 2014 |
Compositions, kits and methods for initiating or accelerating
curing of endodontic filler or sealer compositions placed on a root
canal
Abstract
Activating endodontic points and dental tools are sized and
configured to be placed in the root canal of a tooth. The
activating endodontic points or dental tools are coated or
impregnated with a curing agent that initiates or accelerates
polymerization of a sealer or filler composition when placed in
contact with the sealer or filler material. Curing agents can
include amines that can destabilize a peroxide in the sealer or
filler material to initiate or accelerate polymerization, or they
may comprise the peroxide. An implement can be dipped in a
concentrated curing composition just prior to inserting the
implement into a root canal to contact the filler or sealer
composition. Kits may include a plurality of curing agent
compositions having different concentrations and/or amounts of
curing agent. Kits may also include a curable resin material that
includes a first part of a multi-part curing system and a curing
composition that includes, as curing agent a complementary part of
the curing system.
Inventors: |
Tuttle; Richard D. (Layton,
UT), Wagner; Jeff A. (Salt Lake City, UT), Jessop; Neil
T. (Sandy, UT), Fischer-Jessop; Jaleena (Sandy, UT) |
Applicant: |
Name |
City |
State |
Country |
Type |
Ultradent Products, Inc. |
South Jordan |
UT |
US |
|
|
Assignee: |
Ultradent Products, Inc. (South
Jordan, UT)
|
Family
ID: |
37884591 |
Appl.
No.: |
13/722,653 |
Filed: |
December 20, 2012 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
11530787 |
Sep 11, 2006 |
7863349 |
Jan 4, 2011 |
|
|
Current U.S.
Class: |
523/116;
433/224 |
Current CPC
Class: |
A61C
5/50 (20170201); A61C 5/40 (20170201) |
Current International
Class: |
A61K
6/08 (20060101) |
Field of
Search: |
;433/224,102,81
;523/116 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
0821931 |
|
Feb 1998 |
|
EP |
|
1375619 |
|
Jan 2004 |
|
EP |
|
60-45510 |
|
Mar 1985 |
|
JP |
|
61-151104 |
|
Jul 1986 |
|
JP |
|
61-176506 |
|
Aug 1986 |
|
JP |
|
63-162769 |
|
Jul 1988 |
|
JP |
|
70-82115 |
|
Mar 1995 |
|
JP |
|
80-99811 |
|
Apr 1996 |
|
JP |
|
90-25208 |
|
Jan 1997 |
|
JP |
|
Other References
Ventura, G., et al., Morphological changes on gold-coated brass
endodontic pins; Instituto di Clinica Odontoiatrica, Universitita
degli Studi, Genova; Minerva Stomatol, vol. 44(6), pp. 273-283
(1995). cited by applicant .
Chana, H., et al., Degradation of a silver point in association
with endodontic infection; Int. Endod J., vol. 31(2), pp. 141-146
(1998). cited by applicant .
Musikant, B.L., et al., Simplified Obturation of Tapered Canal
Preparations; Compend. Contin. Educ. Dent., vol. 19(11), pp.
1152-1155 (1998). cited by applicant .
Musikant, B.L., et al., Report of a Simplified Endodontic
Technique; Compend. Contin. Educ. Dent., vol. 20(11), pp.
1088-1090, 1092-1094 (1999). cited by applicant .
Seidman, D., A General Dentist's Viewpoint of Two New Endodontic
Techniques; Compend. Contin. Educ. Dent., vol. 20(10), pp. 921-924,
926, 928 passim; quiz 934 (1999). cited by applicant .
Musikant, B.L., et al., The Evolution of Instrumentation and
Obturation Leading to a Simplifed Approach; Compend. Contin. Educ.
Dent., vol. 21(11), pp. 980-986, 998, 990 (2000). cited by
applicant .
Office action dated Mar. 20, 2008 cited in related U.S. Appl. No.
11/109,424. cited by applicant .
Office action dated Mar. 8, 2007 cited in U.S. Appl. No.
10/843,654. cited by applicant .
Notice of Allowance dated Sep. 25, 2007 cited in related U.S. Appl.
No. 10/843,654. cited by applicant .
Office Action dated Aug. 26, 2008 from U.S. Appl. No. 11/109,424.
cited by applicant .
Office Action dated Oct. 16, 2008 from U.S. Appl. No. 11/232,062.
cited by applicant.
|
Primary Examiner: Singh; Sunil K
Attorney, Agent or Firm: Workman Nydegger
Claims
What is claimed is:
1. A curing composition for use in initiating or accelerating
curing of a filler or sealer composition placed in a root canal of
a tooth, the curing composition consisting essentially of: a liquid
carrier in an amount of 0% to about 75%; and a curing agent that is
only one part of a multi-part chemical curing system in order to
initiate or accelerate curing of a filler or sealer composition
placed within a root canal of a tooth which contains a
complementary part of the multi-part chemical curing system,
wherein the curing agent has a concentration in a range of about
25% to 100% by weight of the curing composition, wherein the curing
agent does not react until contacted with a filler or sealer
composition containing a complementary part of the multi-part
chemical curing system, the curing composition having a flowability
so as to facilitate coating onto or impregnation within an
implement that is sized so as to be at least partially insertable
into a root canal of a tooth.
2. A curing composition as defined in claim 1, wherein the liquid
carrier comprises a non-polymerizable solvent.
3. A curing composition as defined in claim 1, wherein the liquid
carrier comprises a polymerizable hydrophilic resin.
4. A curing composition as defined in claim 1, wherein the curing
agent is an additive compound that destabilizes a peroxide
initiator contained in a sealer or filler composition.
5. A curing composition as defined in claim 4, wherein the additive
compound comprises an amine selected from the group consisting of
dimethylamino ethyl methacrylate, triethyl amine, 2-dimethylamino
ethanol, diethylamino ethyl methacrylate, trihexyl amine,
N,N-dimethyl-p-toluidine, N-methylethanolamine, 2,2'(p-tolyimino)
diethanol, derivatives thereof, and combinations thereof.
6. A curing composition as defined in claim 1, wherein the curing
agent is an initiator that is destabilized by an additive compound
contained in a sealer or filler composition.
7. A curing composition as defined in claim 6, wherein the
initiator comprises a peroxide selected from the group consisting
of benzoyl peroxide, 2-butanone peroxide, lauroyl peroxide,
tert-butyl peroxide, derivatives thereof, and combinations
thereof.
8. A curing composition as defined in claim 1, wherein the curing
agent is selected to catalyze an epoxy-based polymer
composition.
9. A curing composition as defined in claim 8, wherein the curing
agent is selected from the group consisting of strong bases,
amines, and hexamethylenetramine.
10. A curing composition as defined in claim 1, wherein the curing
agent is selected to catalyze a cationic-based polymer
composition.
11. A curing composition as defined in claim 1, wherein the curing
agent has a concentration in a range of about 35% to about 75% by
weight of the curing composition.
12. A curing composition as defined in claim 1, wherein the curing
agent has a concentration in a range of about 45% to about 55% by
weight of the curing composition.
13. A curing composition as defined in claim 1, wherein the curing
composition is pre-packaged in a microdose container.
14. A curing composition as defined in claim 13, wherein the
microdose container contains from about 0.01 ml to about 1 ml of
the curing composition.
15. A curing composition as defined in claim 13, wherein the
microdose container contains from about 0.05 ml to about 0.5 ml of
the curing composition.
16. A curing composition as defined in claim 13, wherein the
microdose container contains from about 0.075 ml to about 2.5 ml of
the curing composition.
17. A kit for use in controlling cure time of a filler or sealer
composition comprising the curing composition of claim 1
pre-packaged within a plurality of microdose containers.
18. A kit as defined in claim 17, wherein the kit comprises at
least two microdose containers containing different concentrations
and/or amounts of the curing agent.
19. A kit for use in controlling cure time of a filler or sealer
composition comprising the curing composition of claim 1 and a
filler or sealer composition containing a complementary part of the
multi-part chemical curing system.
20. A kit for use in controlling cure time of a filler or sealer
composition comprising the curing composition of claim 1 and one or
more implements for introducing the curing composition into a root
canal of a tooth and that are sized so as to be at least partially
insertable into a root canal of a tooth.
21. A kit as defined in claim 20, wherein the one or more
implements comprise one or more gutta percha cones.
22. A kit for use in initiating or accelerating curing of a filler
or sealer composition placed in a root canal of a tooth,
comprising: an endodontic filler or sealer composition stored in a
first container and containing a first part of a multi-part
chemical curing system; and a curing composition stored in a second
container and which contains a curing agent that is only a
complementary part of the multi-part chemical curing system in
order to initiate or accelerate curing of the filler or sealer
composition when contacted therewith in a root canal of a tooth,
wherein the curing agent has a concentration in a range of about
25% to 100% by weight of the curing composition, wherein the curing
agent does not react until contacted with the endodontic filler or
sealer composition containing the first part of the multi-part
chemical curing system, the curing composition having a flowability
so as to facilitate coating onto or impregnation within an
implement that is sized so as to be at least partially insertable
into a root canal of a tooth.
23. A kit as defined in claim 22, wherein the filler or sealer
composition contains a peroxide initiator and the curing
composition contains an amine additive that destabilizes the
peroxide initiator when the curing composition is contacted with
the filler or sealer composition.
24. A kit as defined in claim 22, wherein the curing composition
contains a peroxide initiator and the filler or sealer composition
contains an amine additive that destabilizes the peroxide initiator
when the curing composition is contacted with the filler or sealer
composition.
25. A kit for use in initiating or accelerating curing of a filler
or sealer composition placed in a root canal of a tooth,
comprising: a curing composition containing a curing agent that is
only one part of a multi-part chemical curing system in order to
initiate or accelerate curing of a filler or sealer composition
placed within a root canal of a tooth which contains a
complementary part of the multi-part chemical curing system,
wherein the curing agent has a concentration of at least about 25%
by weight of the curing composition, wherein the curing agent does
not react until contacted with a filler or sealer composition
containing a complementary part of the multi-part chemical curing
system, the curing composition having a flowability so as to
facilitate coating onto or impregnation within an implement that is
sized so as to be at least partially insertable into a root canal
of a tooth; and a plurality of implements that are sized so as to
be at least partially insertable within a root canal of a tooth in
order to facilitate contact of the curing composition with a filler
or sealer composition placed within a root canal of a tooth,
wherein coating or impregnating one of the implements with the
curing agent yields a coated or impregnated implement that is sized
so as to be at least partially insertable into a root canal of a
tooth.
26. A kit as defined in claim 25, wherein the implements comprise
one or more endodontic cones.
27. A kit as defined in claim 25, wherein the implements comprise
one or more dental tools.
28. A kit as defined in claim 25, wherein the implements comprise
one or more plastic fragments.
.Iadd.29. A curing composition for use in initiating curing of a
filler or sealer composition placed in a root canal of a tooth, the
curing composition consisting essentially of: a liquid carrier and
a curing agent that is only one part of a multi-part chemical
curing system in order to initiate curing of a filler or sealer
composition placed within a root canal of a tooth which contains a
complementary part of the multi-part chemical curing system,
wherein the curing agent has a concentration in a range of about 5%
to 35% by weight of the curing composition, wherein the curing
agent does not react until contacted with a filler or sealer
composition containing a complementary part of the multi-part
chemical curing system, the curing composition having a flowability
so as to facilitate coating onto or impregnation within an
implement that is sized so as to be at least partially insertable
into a root canal of a tooth..Iaddend.
.Iadd.30. A curing composition as defined in claim 29, wherein the
curing agent has a concentration in a range of about 5% to 25% by
weight of the curing composition..Iaddend.
.Iadd.31. A curing composition as defined in claim 29, wherein the
curing agent has a concentration in a range of about 20% to 25% by
weight of the curing composition..Iaddend.
.Iadd.32. A curing composition as defined in claim 29, wherein the
liquid carrier comprises a non-polymerizable solvent..Iaddend.
.Iadd.33. A curing composition as defined in claim 29, wherein the
liquid carrier comprises a polymerizable hydrophilic
resin..Iaddend.
.Iadd.34. A curing composition as defined in claim 29, wherein the
curing agent is an additive compound that destabilizes a peroxide
initiator contained in a sealer or filler composition..Iaddend.
.Iadd.35. A curing composition as defined in claim 34, wherein the
additive compound comprises an amine selected from the group
consisting of dimethylamino ethyl methacrylate, triethyl amine,
2-dimethylamino ethanol, diethylamino ethyl methacrylate, trihexyl
amine, N,N-dimethyl-p-toluidine, N-methylethanolamine,
2,2'(p-tolyimino) diethanol, derivatives thereof, and combinations
thereof..Iaddend.
.Iadd.36. A curing composition as defined in claim 29, wherein the
curing agent is an initiator that is destabilized by an additive
compound contained in a sealer or filler composition..Iaddend.
.Iadd.37. A curing composition as defined in claim 36, wherein the
initiator comprises a peroxide selected from the group consisting
of benzoyl peroxide, 2-butanone peroxide, lauroyl peroxide,
tert-butyl peroxide, derivatives thereof, and combinations
thereof..Iaddend.
.Iadd.38. A curing composition as defined in claim 29, wherein the
curing agent is selected to catalyze an epoxy-based polymer
composition..Iaddend.
.Iadd.39. A curing composition as defined in claim 38, wherein the
curing agent is selected from the group consisting of strong bases,
amines, and hexamethylenetramine..Iaddend.
.Iadd.40. A curing composition as defined in claim 29, wherein the
curing agent is selected to catalyze a cationic-based polymer
composition..Iaddend.
.Iadd.41. A curing composition as defined in claim 29, wherein the
curing composition is pre-packaged in a microdose
container..Iaddend.
.Iadd.42. A curing composition as defined in claim 41, wherein the
microdose container contains from about 0.01 ml to about 1 ml of
the curing composition..Iaddend.
.Iadd.43. A curing composition as defined in claim 41, wherein the
microdose container contains from about 0.05 ml to about 0.5 ml of
the curing composition..Iaddend.
.Iadd.44. A curing composition as defined in claim 41, wherein the
microdose container contains from about 0.075 ml to about 2.5 ml of
the curing composition..Iaddend.
.Iadd.45. A kit for use in initiating curing of a filler or sealer
composition comprising the curing composition of claim 29
pre-packaged within a plurality of microdose
containers..Iaddend.
.Iadd.46. A kit as defined in claim 45, wherein the kit comprises
at least two microdose containers containing different
concentrations and/or amounts of the curing agent..Iaddend.
.Iadd.47. A kit for use in initiating curing of a filler or sealer
composition comprising the curing composition of claim 29 and a
filler or sealer composition containing a complementary part of the
multi-part chemical curing system..Iaddend.
.Iadd.48. A kit for use in initiating curing of a filler or sealer
composition comprising the curing composition of claim 29 and one
or more implements for introducing the curing composition into a
root canal of a tooth and that are sized so as to be at least
partially insertable into a root canal of a tooth..Iaddend.
.Iadd.49. A kit as defined in claim 48, wherein the one or more
implements comprise one or more gutta percha cones..Iaddend.
.Iadd.50. A kit for use in initiating curing of a filler or sealer
composition placed in a root canal of a tooth comprising: an
endodontic filler or sealer composition stored in a first container
and containing a first part of a multi-part chemical curing system;
and a curing composition stored in a second container and which
contains a curing agent that is only a complementary part of the
multi-part chemical curing system in order to initiate curing of
the filler or sealer composition when contacted therewith within a
root canal of a tooth, wherein the curing agent has a concentration
in a range of about 5% to 35% by weight of the curing composition,
wherein the curing agent does not react until contacted with the
endodontic filler or sealer composition containing the first part
of the multi-part chemical curing system, the curing composition
having a flowability so as to facilitate coating onto or
impregnation within an implement that is sized so as to be at least
partially insertable into a root canal of a tooth..Iaddend.
.Iadd.51. A kit as defined in claim 50, wherein the curing agent
has a concentration in a range of about 5% to 25% by weight of the
curing composition..Iaddend.
.Iadd.52. A kit as defined in claim 50, wherein the filler or
sealer composition contains a peroxide initiator and the curing
composition contains an amine additive that destabilizes the
peroxide initiator when the curing composition is contacted with
the filler or sealer composition..Iaddend.
.Iadd.53. A kit as defined in claim 50, wherein the curing
composition contains a peroxide initiator and the filler or sealer
composition contains an amine additive that destabilizes the
peroxide initiator when the curing composition is contacted with
the filler or sealer composition..Iaddend.
.Iadd.54. A kit for use in initiating curing of a filler or sealer
composition placed in a root canal of a tooth comprising: a curing
composition containing a curing agent that is only one part of a
multi-part chemical curing system in order to initiate or
accelerate curing of a filler or sealer composition placed within a
root canal of a tooth which contains a complementary part of the
multi-part chemical curing system, wherein the curing agent has a
concentration of about 5% to about 35% by weight of the curing
composition, wherein the curing agent does not react until
contacted with a filler or sealer composition containing a
complementary part of the multi-part chemical curing system the
curing composition having a flowability so as to facilitate coating
onto or impregnation within an implement that is sized so as to be
at least partially insertable into a root canal of a tooth; and a
plurality of implements that are sized so as to be at least
partially insertable within a root canal of a tooth in order to
facilitate contact of the curing composition with a filler or
sealer composition placed within a root canal of a tooth, wherein
coating or impregnating one of the implements with the curing agent
yields a coated or impregnated implement that is sized so as to be
at least partially insertable into a root canal of a
tooth..Iaddend.
.Iadd.55. A kit as defined in claim 54, wherein the curing agent
has a concentration in a range of about 5% to 25% by weight of the
curing composition..Iaddend.
.Iadd.56. A kit as defined in claim 54, wherein the implements
comprise one or more endodontic cones..Iaddend.
.Iadd.57. A kit as defined in claim 54, wherein the implements
comprise one or more dental tools..Iaddend.
.Iadd.58. A kit as defined in claim 54, wherein the implements
comprise one or more plastic fragments..Iaddend.
.Iadd.59. A curing composition for use in initiating curing of a
filler or sealer composition placed in a root canal of a tooth, the
curing composition consisting essentially of: a non-polymerizable
liquid carrier; and a curing agent that is only one part of a
multi-part chemical curing system in order to initiate curing of a
filler or sealer composition placed within a root canal of a tooth
which contains a complementary part of the multi-part chemical
curing system, wherein the curing agent has a concentration in a
range of about 0.1% to 35% by weight of the curing composition,
wherein the curing agent does not react until contacted with a
filler or sealer composition containing a complementary part of the
multi-part chemical curing system, the curing composition having a
flowability so as to facilitate coating onto or impregnation within
an implement that is sized so as to be at least partially
insertable into a root canal of a tooth..Iaddend.
.Iadd.60. A curing composition as defined in claim 59, wherein the
non-polymerizable liquid carrier is a non-polymerizable solvent
selected from the group consisting of water, methanol, ethanol,
isopropyl alcohol, propylene glycol, 1,3-propanediol, glycerin,
polyethylene glycol, polypropylene glycol, actone, toluene, xylene,
ethyl acetate, DMSO, DMF, acetonitrile, and mixtures
thereof..Iaddend.
.Iadd.61. A curing composition as defined in claim 59, wherein the
curing agent has a concentration in a range of about 0.1% to 20% by
weight of the curing composition..Iaddend.
.Iadd.62. A curing composition as defined in claim 59, wherein the
curing agent has a concentration in a range of about 1% to 2% by
weight of the curing composition..Iaddend.
.Iadd.63. A curing composition as defined in claim 59, wherein the
curing agent is an additive compound that destabilizes a peroxide
initiator contained in a sealer or filler composition..Iaddend.
.Iadd.64. A curing composition as defined in claim 63, wherein the
additive compound comprises an amine selected from the group
consisting of dimethylamino ethyl methacrylate, triethyl amine,
2-dimethylamino ethanol, diethylamino ethyl methacrylate, trihexyl
amine, N,N-dimethyl-p-toluidine, N-methylethanolamine,
2,2'(p-tolyimino) diethanol, derivatives thereof, and combinations
thereof..Iaddend.
Description
CROSS-REFERENCE TO RELATED APPLICATION
N/A
BACKGROUND OF THE INVENTION
1. The Field of the Invention
The present invention relates to concentrated curing compositions
for use in initiating or accelerating curing endodontic sealer and
filler compositions placed in a person's root canal. In addition,
the invention relates to kits that include a microdose container
filled with a concentrated curing composition used to coat or
impregnate a dental tool for use in initiating or accelerating
curing of an endodontic sealer or filler composition.
2. The Related Technology
In an endodontic root canal procedure, the root canal is typically
cleaned using special root canal tools and irrigation devices.
Following such a root canal procedure, it is important to fill and
seal the evacuated root canal to preserve the dead tooth from
further decay that might compromise the integrity of the tooth and
cause infection. In a typical procedure, one or more soft,
resilient, needle-like inserts known as "gutta percha" cones or
points are inserted in each root canal branch to at least partially
seal and fill the root canal.
The term "gutta percha" refers to a rubbery material derived from
natural rubber and typically blended with zinc oxide. This
particular rubbery material is preferred because it is
compressible, flexible and relatively soft so that it can be used
to fill voids within the exposed root canal. The gutta percha cones
are typically impregnated with other materials such as radiopaque
solids, zinc oxide, for its medicinal properties, and other passive
or active ingredients as desired.
Filling a root canal with gutta percha often requires inserting
more than one gutta percha point or cone. Most root canals are
narrow at the apical end and widen as they move up through the
tooth. The first gutta percha point or cone is used to seal the
apex and is often referred to as the master cone. Following
placement of the master cone, additional gutta percha points can be
added to fill the increasingly larger void of the root canal.
Experience has shown that it is impossible to completely seal a
root canal using gutta percha alone. To further seal the root
canal, flowable materials, such as sealing resins, are inserted
into the root canal along with the gutta percha points. One feature
of most sealing resins is the need to harden or cure the resin. The
sealing resin remains in a liquid state until polymerized by an
initiator or curing agent. Because root canals are deep and narrow,
photocuring a resin deep within the root canal is not possible. A
chemical curing agent must be employed. The curing agent is
typically mixed with the resin just prior to inserting the resin in
the root canal, thereby giving the practitioner the greatest amount
of time to work before the resin hardens.
One disadvantage of chemically curable resins is that once chemical
curing begins the reaction cannot be easily stopped or inhibited.
Thus, a practitioner has only a limited time to work with the
material once hardening begins. In theory, this window of time can
be lengthened or shorted in advance by selecting the amount or type
of curing agent that is mixed with the curable resin. If the time
is lengthened, the hardening step may take an undesirably long
amount of time once the resin is placed in the tooth. If the time
is shorted, the practitioner may be rushed if the procedure turns
out to be more difficult than anticipated. Thus, while the cure
time can be modified, at least in theory, before the procedure
begins, once curing has been initiated, curing will proceed within
whatever time frame is dictated by the curing agent. Depending on
the temperature, extent of mixing, and other variable factors, the
actual window of time in which the resin will cure may be
unpredictable.
This inability to modify cure times once curing has been initiated
can make certain steps of a root canal procedure difficult or
impossible. For example, a practitioner may not have sufficient
time to take an X-ray to determine whether the sealing material has
successfully filled the entire root canal, including lateral canals
and/or whether the gutta percha points have been properly
positioned. Alternatively, the curing process may take too much
time, thus wasting the patient's and the practitioner's time or
making it necessary for the patient to return for a follow up
procedure after the resin has fully hardened.
Therefore, what is needed are compositions, kits and methods that
can be employed to reliably cure a curable resin placed within a
person's root canal while giving the practitioner flexibility to
increase or decrease the time the practitioner has to work with the
resin while carrying out the dental filling procedure.
BRIEF SUMMARY OF THE INVENTION
The present invention overcomes the above mentioned problems in the
prior art by providing curing compositions, kits and methods that
allow a practitioner to control the timing and/or extent of the
curing of an endodontic filler or sealer composition within a
person's root canal. The curing composition is provided in
concentrated form so that only a small quantity of the curing
composition is required to initiate curing, which typically
involves free radical polymerization and/or cross linking of one or
more curable resins contained within the filler or sealer
composition. The curable resins may include monomers, dimers,
trimers, oligomers or other polymerizable units having
ethylenically unsaturated groups (e.g., acrylic acid, methacrylic
acid, or esters thereof).
In order to initiate and/or accelerate curing of an endodontic
filler or sealer composition placed within a root canal, a suitably
sized implement, such as an endodontic point or dental tool, is
first coated or impregnated with the curable composition and then
placed in the root canal containing the filler or sealer
composition. According to one embodiment, coating or impregnating
the implement is performed by the dental practitioner just prior to
inserting the implement into the root canal. In one embodiment, the
practitioner dips the implement in a vial containing a curing
composition in concentrated form (e.g., a curing agent in a solvent
or other carrier liquid). Because curing agents can be toxic, the
concentrated curing composition is advantageously pre-packaged in a
microdose container.
In another embodiment, the curing agent may be pre-coated on or
impregnated within the implement, thereby forming an activating
implement (e.g., endodontic point or dental tool). When the
activating endodontic point or dental tool is placed in contact
with a sealer or filler composition in a root canal, the endodontic
point or dental tool initiates or accelerates polymerization of the
sealer or filling material. The amount of curing agent pre-coated
on or impregnated within the implement will typically be such that
a desired level of curing will be attained (e.g., partial or total
curing). Nevertheless, it is not so much the amount of curing agent
but when the curing agent is first contacted with the filler or
sealing composition within the root canal that is the main
determining factor regarding the timing and/or extent of
curing.
The curing agent can be any one of a number of components used to
cure sealer or filler compositions. In an exemplary embodiment, the
curing agent comprises one or more amines that initiate or
accelerate polymerization of the sealer or filling composition by
destabilizing a peroxide contained within the sealer or filler
composition. The destabilized peroxide can then initiate free
radical polymerization (e.g., of an acrylate- or methacrylate-based
sealer or filler composition). Alternatively, the curing agent may
comprise one or more peroxides that are initially stable when
coated or impregnated onto the implement but which are destabilized
by one or more amines contained within the sealer or filler
composition. Other polymerizable sealer or filler compositions that
can be initiated using an appropriate curing agent coated on or
impregnated within an implement, such as an endodontic point or
dental tool, include epoxy- or cationic-based compositions.
A kit for use in initiating or accelerating curing of an endodontic
filler or sealer composition may include one or more microdose
containers, each including an appropriate quantity and/or
concentration of curing composition. Because the curing agent can
be toxic, particularly in the case of amines, a microdose container
containing a very small quantity of the curing composition can be
provided. By way of example, microdose containers within the scope
of the invention may contain from about 0.01 ml to about 1 ml of
the curing composition, preferably from about 0.05 ml to about 0.5
ml, and more preferably from about 0.075 ml to about 0.25 ml.
According to one embodiment, the microdose container contains about
0.1-0.15 ml of the curing composition.
It is within the scope of the invention to provide curing
compositions having differing concentrations and/or amounts of
curing agent in order to provide different cure times. In this
embodiment, a dental practitioner can select an appropriate
composition from the kit and dip an implement or substrate into the
curing agent composition so as to form the activating implement or
substrate just prior to use. The dental practitioner can control
the cure time by selecting the proper curing agent composition. The
kit may optionally include one or more implements (e.g., rigid
elongated devices, such as plastic or metal rods) that may be
coated and/or impregnated with the curing composition prior to
inserting an implement within a filler or sealer composition within
a root canal to initiate and/or accelerate curing thereof.
Alternatively, kits within the scope of the invention may include
one or more endodontic filler or sealer compositions and one or
more microdose containers that contain appropriate amounts and/or
concentrations of curing composition (e.g., to provide single or
variable cure times). The endodontic filler or sealer composition
may be pre-packaged within an appropriate container, such as a
syringe. One or more syringe tips containing a cannula sufficiently
narrow to be placed within a root canal may be provided with the
kit. The filler or sealer compositions may include part of a curing
system complementary to the curing composition. They may also
comprise two-part chemical cure compositions that include an amount
of curing agent when mixed so that only slow curing occurs. The
curing compositions are then used to merely accelerate rather than
initiate curing. Such kits may also include one or more implements
as previously discussed.
In an alternative embodiment, kits are provided that include a
plurality of implements that are pre-coated or impregnated with a
curing agent. In one embodiment, the implements may include
different amounts of curing agent so as to provide different cure
times. The kit may include endodontic cones that are intended to be
sequentially placed into a root canal during a filling or sealing
procedure. In such case, one or more cones that are to be placed
first may include an amount of curing agent that only initiates
slow curing of the filler or sealer composition. One or more cones
that are to be placed later may include an amount of curing agent
that more rapidly cures the filler or sealer composition.
For example, a kit containing one or more master cones and one or
more accessory cones can be used to select when or how fast to
initiate the curing process. According to one embodiment, the
master cone may be treated with a curing agent to initiate either
slow or fast curing. Accessory cones designed to be placed into a
root canal after the master cone can be treated with a curing
agent. In the case where the master cone is treated to initiate
slower curing one or more accessory cones can be used to initiate
faster curing. In some cases only the accessory cones will be
treated such that the master cone does not itself initiate
curing.
The present invention also includes methods for performing an
endodontic procedure. The methods of the present invention include
performing a root canal on the tooth of a person or animal to
prepare the root canal for a sealer or filling composition, placing
a sealer or filler composition in the root canal, and initiating or
accelerating the polymerization of the filler or sealer composition
by placing an activating endodontic point or dental tool in contact
with the sealer or filler composition. The method may employ any of
the inventive compositions and/or kits disclosed herein to provide
a desired rate or extent of curing of the filler or sealer
compositions positioned within the root canal.
The compositions, kits and methods of the present invention allow a
practitioner to better control when a sealer or filler composition
is cured during the endodontic procedure and the time within which
curing will occur. Using the present invention, a practitioner can
prepare and place a curable sealer or filling material in the root
canal and wait for a desired amount of time before initiating or
causing complete polymerization and/or cross linking. The
practitioner can control the timing of curing by selecting when to
place the activating endodontic point or dental tool in the sealer
or filler material. Furthermore, by controlling the concentration
and/or amount of curing agent on or within the endodontic point,
dental tool or other implement, the rate of polymerization can also
be controlled. Unlike light curing alone, which may only cure an
upper portion of the sealer or filler material, the present
invention allows for complete curing along the entire root
canal.
Providing the practitioner with better control over the timing and
duration of curing reduces the time and expense of an endodontic
procedure and can improve the quality of the procedure. One
advantage of controlling cure timing is that the practitioner can
choose to perform a step, such as taking X-rays, to determine
proper placement of the filler or sealer material and/or endodontic
point (e.g., a master cone). Because the practitioner can select
when to cause curing of the sealer or filler material, the
practitioner can cause very rapid curing after performing any
necessary prep work. This allows subsequent procedures, such as
restorative procedures, to be performed immediately following the
sealing or filling procedure. For example, this feature can allow a
patient to receive a root canal and a restorative post procedure in
a single office visit.
BRIEF DESCRIPTION OF THE DRAWINGS
To further clarify the above and other advantages and features of
the present invention, a more particular description of the
invention will be rendered by reference to specific embodiments
thereof which are illustrated in the appended drawings. It is
appreciated that these drawings depict only typical embodiments of
the invention and are therefore not to be considered limiting of
its scope. The invention will be described and explained with
additional specificity and detail through the use of the
accompanying drawings in which:
FIG. 1 illustrates an exemplary tooth with its root prepared in an
endodontic procedure for sealing and filling according to an
exemplary embodiment of the present invention;
FIG. 2 illustrates placement of an endodontic point in the apex of
the tooth of FIG. 1;
FIG. 3 illustrates filling the root canal of the tooth of FIG. 2
with an endodontic sealer or filler composition;
FIG. 4 illustrates the tooth of FIG. 2 partially filled with a
sealer or filler composition;
FIGS. 5A and 5B illustrate the act of dipping an endodontic cone
into a microdose container that contains therein a microdose of a
curing composition; and
FIG. 6 shows the tooth and filler or sealer composition of FIG. 4
with a pair of activating accessory endodontic points placed in the
sealer or filler composition to initiate or accelerate curing.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The invention encompasses compositions, kits and methods used to
control the timing and/or extent of curing sealer and filler
compositions placed in a root canal during an endodontic procedure.
Curing compositions include a curing agent in concentrated form. An
implement such as an endodontic point or dental tool can be coated
or impregnated with the curing composition and then inserted into a
filler or sealer composition positioned within a root canal.
Alternatively, the endodontic point or dental instrument may be
pre-coated or impregnated with a curing agent to form an activating
implement. When contacted with a sealer or filler composition, the
curing agent initiates or accelerates polymerization and/or cross
linking of the sealer or filler composition. The timing when curing
of the endodontic filler or sealer composition can be controlled by
selecting when to contact the curable composition with the curing
agent. Furthermore, the cure time can be further controlled by
controlling the concentration and/or amount of curing agent that is
coated on or impregnated within the implement.
According to one embodiment, the curing composition can be used to
initiate curing of a filler or sealer composition placed in a root
canal. In another embodiment, the curing composition can be used to
accelerate curing of a filler or sealer composition placed in a
root canal that has already begun to cure but which is curing
slowly to provide adequate time for the endodontist to perform
desired and/or necessary procedures prior to final cure.
I. CURING AGENTS AND COMPOSITIONS
Curing compositions within the scope of the invention preferably
contain one or more curing agents in concentrated form. That allows
a small amount of the curing composition to quickly initiate and/or
accelerate curing of a filler or sealer composition within a root
canal.
An appropriate curing agent is selected to initiate or accelerate
polymerization of the particular sealer or filler composition being
used to fill and/or seal the root canal. The curing agent may be
one part of a curing system that is capable of polymerizing the
sealer or filler composition. Generally, any component of a curing
system can be used as the curing agent so long as that compound can
initiate and/or accelerate polymerization of the sealer or filler
composition. The curing agent may be selected to initiate curing of
any polymerizable sealant or filler composition, including but not
limited to, acrylic acid- and/or methacrylic acid-based
compositions, acrylate- and/or methacrylate-based compositions,
epoxy-based compositions, and cationic-based compositions.
The curing agent can be coated on or impregnated within an
implement, such as an endodontic cone or dental tool, either prior
to or just before use. When the coated or impregnated substrate or
implement is placed in contact with a sealer or filler composition,
the curing agent causes polymerization and/or cross linking of the
sealer or filler composition.
The curing agent of the present invention can be a chemical
initiator or it can be an additive that works with a chemical
initiator to initiate or accelerate polymerization of the sealer or
filler composition. Chemical initiators are compounds that induce
polymerization and/or cross linking (e.g., free radical
polymerization and/or cross linking) of the polymerizable material.
Additives are compounds that react with initiators in order to
cause the initiators to induce polymerization and/or cross
linking.
Examples of chemical initiators that induce free radical
polymerization and/or cross linking include a wide range of
peroxides, other per compounds, and other free radical generators.
Exemplary peroxides include benzoyl peroxide, 2-butanone peroxide,
lauroyl peroxide and tert-butyl peroxide. Peroxides are typically
stable, or can be made stable, until it is desired to initiate free
radical polymerization and/or cross linking. An additive is used to
destabilize the peroxide, causing free radicals to be generated
that are able to then induce polymerization and/or cross linking of
the curable composition (e.g., by means of free radical induced
polymerization and/or cross linking of ethylenically unsaturated
groups contained in the polymerizable units).
Examples of additives that can be used to destabilize peroxide
initiators include a wide variety of amines (i.e., amino
compounds). Examples of amino compounds include dimethylamino ethyl
methacrylate, triethyl amine, 2-dimethylamino ethanol, diethylamino
ethyl methacrylate, trihexyl amine, N,N-dimethyl-p-toluidine (also
referred to as DMPT), N-methylethanolamine,
2,2'(p-tolyimino)diethanol (also referred to as P-TIDE), and
derivatives thereof.
According to one embodiment, the curing composition applied to a
substrate or implement and then inserted into the curable resin to
initiate or accelerate curing comprises an amine or other additive
that is able to react with and destabilize a peroxide or other
initiator that is already mixed within the curable resin within the
root canal. In another embodiment, the curing composition applied
to a substrate or implement and then inserted into the curable
resin to initiate or accelerate curing comprises a peroxide or
other initiator that is able to react with and become destabilized
by an amine or other additive that is already mixed within the
curable resin within the root canal.
The curing agent, whether an initiator or additive, is preferably
contained in high concentration within the curing composition,
typically as a solution or suspension together with an appropriate
solvent or carrier liquid. This allows a relatively small amount of
the curing composition coated on or impregnated within an implement
to initiate or accelerate curing of an endodontic filler or sealer
composition placed within a root canal. Accordingly, the curing
agent may have a concentration in a range of about 25% to 100% by
weight of the curing composition, preferably from about 35% to
about 75% by weight, and most preferably from about 45% to about
55% by weight.
Any appropriate solvent or other carrier liquid can be mixed with
the curing agent to yield a curing composition having a desired
concentration of curing agent. A solvent or other carrier is
typically selected that does not itself react with the curing
agent. The solvent may be non-reactive or it may itself be capable
of polymerizing. The curing composition is preferably fluid and
non-viscous to facilitate fast diffusion of the curing composition
into the curable composition. Examples of non-polymerizable
solvents and other carriers that may be used to formulate curing
compositions within the scope of the invention include water,
methanol, ethanol, iso-propyl alcohol, propylene glycol,
1,3-propanediol, glycerin, polyethylene glycol, polypropylene
glycol, acetone, toluene, xylene, ethyl acetate, DMSO, DMF, and
acetonitrile. An examples of a polymerizable solvent or carrier is
triethylene glycol dimethacrylate (TEG-DMA).
As discussed more fully below, the curing composition can be
pre-coated on or impregnated within an implement, such as an
endodontic cone, to form an activating dental implement or
substrate. Depending on the chemical make up of the implement, the
curing composition that is pre-coated on or impregnated in the
implement may simply include a curing agent and solvent or other
carrier liquid, as discussed above. Alternatively, the curing
composition may further include one or more polymerizable materials
in order to improve adhesion of the curing agent to the substrate,
particularly in the case where the substrate is hydrophobic, such
as gutta percha, or otherwise has a tendency to repel the curing
agent.
The curing agent may optionally include a preservative such as a
free-radical scavenger, which is especially advantageous in the
case where the solvent or carrier is capable of free radical
polymerization. An example of a free radical scavenger that can be
used to prevent premature polymerization of a polymerizable solvent
or carrier is butylated hydroxytoluene (BHT). Another is butylated
hydroxyanisole (BHA).
II. ACTIVATING IMPLEMENTS
In a preferred embodiment, the activating substrate or implement of
the present invention is an endodontic point. However, almost any
material that can be sized and configured for insertion into a root
canal of a person can be used as the substrate for the present
invention. FIG. 1 depicts a tooth 10 that has been subjected to a
root canal procedure such that a substrate can be inserted therein.
The tooth 10 includes a root canal 12 in tooth root 14. Root canal
12 includes root canal portions 16a and 16b. Root canal portions
16a and 16b terminate at apexes 18a and 18b, respectively to create
root openings 20a and 20b. Lateral canals 22 extend into root 14
from root canal 12. An opening 24 in the crown of the tooth
provides access to root canal 12.
The substrate of the present invention is sized and configured to
be inserted through opening 24 and into root canal 12. In one
embodiment, the substrate is configured to be, inserted into the
pulp chamber 26. Alternatively, the substrate of the present
invention can be sized and configured to be at least partially
placed in the root canal portions 16a or 16b.
Typically, substrates that can be inserted into root canal 12 have
a diameter between about 0.1 and 1.1 mm for human teeth. Animals
however, can have much larger root canals, such as up to about 20
mm.
In an exemplary embodiment, the substrate of the present invention
is an endodontic point. FIG. 2 shows endodontic points 28a and 28b
inserted into apexes 18a and 18b respectively. As discussed below,
endodontic points 28a and 28b can be coated or impregnated with a
curing agent according to the present invention. Endodontic points
28a and 28b can be made of gutta percha and are used for their
typical benefit, which is to plug or seal root openings 20a and 20b
in root canals 16a and 16b respectively.
Using endodontic points 28a and 28b as a substrate according to the
present invention has the added benefit of not requiring additional
materials or tools to be placed in the root canal. This aspect of
the invention can be particularly beneficial where the substrate
needs to be placed near apex 18 since root canal 16a and 16b can be
very narrow at the apex.
Endodontic points 28a and 28b shown in FIG. 2 are master points and
can be used as a substrate according to the present invention.
However, as shown in FIG. 5, accessory cones such as endodontic
points 38a and 38b can also be used as a substrate. In existing
endodontic procedures, accessory cones are typically used to seal
lateral canals 22, where the master cones are used to plug the
opening in the apex. In the case where accessory cones are used,
only the accessory cones are activating so that curing is not
initiated or accelerated until placement of the accessory cones.
This allows a dentist or endodontist to take one or more X-rays to
ensure proper placement of the filler or sealer and the master
cone(s) prior to initiating or accelerating curing. It is also
within the scope of the invention to use a master cone that is
treated to initiate either fast or slow curing.
In an alternative embodiment, a dental tool or other device can be
used as a substrate. For example, syringe 30, shown in FIG. 3
(e.g., an outer surface of cannula 34), can be used as a substrate
in addition to being used as a tool to inject a sealer composition
into the root canal. Alternatively, the substrate can be another
dental tool such as an endodontic file (not shown) or thin piece of
plastic or other material (not shown) so long as the substrate is
sized and configured to be placed into at least a portion of a root
canal. One of skill in the art would readily be able to select an
appropriate endodontic file or construct a narrow cross-sectioned
implement that can fit at least partially into a root canal.
In an exemplary embodiment, activating implements, such as
endodontic points and dental tools, are made by dipping the
implement or substrate into a composition that includes the curing
agent. In one embodiment, the curing agent is mixed with one or
more of a polymer or a solvent, and the substrate is dipped into
the polymer or solvent. By mixing the curing agent at least one of
a polymer or solvent, the polymer or solvent can be used as a
carrier for coating or impregnating the substrate. In another
embodiment, the substrate is dipped directly into pure curing
agent. However, in the case where only a minute quantity of curing
agent is able to initiate or accelerate curing, it will be
preferable to include a solution of curing agent and solvent.
While any coating or impregnation method can be used to apply the
curing agent to the substrate, using a carrier can be particularly
effective. First, using a carrier can provide an appropriate
distribution of the curing agent over the substrate. For example,
where a dental tool such as a metal tool is being used, a polymeric
mixture can be used that has a viscous or adhesive property that
causes the polymeric mixture to adhere to the dental tool. In
another embodiment, where a gutta percha point is used, a solvent
can be used that can penetrate the gutta percha and impregnate it.
Nevertheless, dental tools and gutta percha endodontic points can
be coated using a polymeric material instead of, or in addition to,
a solvent.
A second advantage of using a carrier such as a solvent or polymer
to deliver the curing agent is that mixing the curing agent allows
the concentration of the curing agent to be controlled. Typically,
the cure time depends on the concentration of the curing agent in
the sealer or filler composition. This is accomplished by making
the curing agent the limiting reagent or choosing a curing agent
that can accelerate the reaction. In one exemplary embodiment, the
curing agent is an amine that destabilizes a peroxide in the sealer
or filler material. The concentration of the amine in the sealer or
filler material determines in large part the magnitude of the cure
time.
Coating or impregnating the substrate by dipping the substrate
directly in a curing agent liquid such as P-TIDE or DMPT results in
cure times of less than about 30 seconds. By mixing the curing
agent with a carrier such as a polymer or a solvent, the cure time
can be extended to any desired amount of time.
Suitable polymers useful as a carrier for the curing agent include
acrylate based polymers such as methacrylates and di-acrylates. In
an exemplary embodiment, the polymers used as a carrier for the
curing agent are similar or identical to the polymers used in the
sealer or filling material. A solvent is typically used to
impregnate an endodontic point or dental tool. An example of a
solvent suitable for using in the present invention is toluene.
In an exemplary embodiment, the curing agent is an amine that is
included in a polymeric material and the concentration of amine is
between about 0.1 and about 35% of the polymeric mixture. The
concentration of curing agent will depend on the curing agent
selected. For example, P-TIDE is typically used in a range of
between about 5% and 35%, and more preferably in a range of about
20%-25% of the coating. A coating having P-TIDE in a concentration
of about 20% to about 25% causes the sealer or filler material in
the root canal to cure in about 2-4 minutes.
In another example, DMPT is used with the solvent toluene,
preferably in a concentration of about 0.1% to about 20%, and more
preferably in a concentration of about 1%-2%. DMPT in a
concentration of about 2% in toluene and impregnated on an
endodontic point causes curing in about 8 minutes when placed in a
sealer or filler in a root canal.
Those skilled in the art will recognize that there are many
combinations of initiators, peroxides, amines, and other compounds
that work with many different curable resins and that these
different compounds can be used as curing agents to carry out the
invention described herein. Those skilled in the art are also
familiar with cure times for various concentrations of curing agent
in curable resins. Thus, while various examples have been provided
for purposes of illustrating the invention, those skilled in the
art can easily adapt these teachings to numerous curable resins and
curing systems that are available for sealing or filling root
canals.
The carrier compounds described above, including polymers and
solvents are examples of carrier compound means for coating or
impregnating a substrate with a curing agent.
When making an activating endodontic point or dental tool according
to the present invention, any portion of the substrate can be
coated or impregnated. Typically, for an endodontic point, the
entire length of the point is coated or impregnated since gutta
percha points may be completely inserted into the root canal. A
dental tool on the other hand is typically only partially inserted
into the root canal. Thus, only a portion of the dental tool is
typically coated or impregnated so as to not waste the active
agent.
The activating endodontic points and dental tools of the present
invention can be coated or impregnated during manufacture.
Alternatively, a curing agent composition can be provided to the
dental practitioner who then mixes and/or dips a substrate in the
curing agent composition to prepare the activating endodontic point
or dental tool just before use.
III. CURABLE FILLING AND SEALING COMPOSITIONS
The endodontic sealer and filler compositions used with the
inventive curing compositions and activating implements or
substrates according to the invention include at least one chemical
curable resin material. The curable resin is initially in a liquid
or shapeable form. As shown in FIGS. 3 and 4, sealer or filler
composition 32 is placed in root canals 16a and 16b. Sealer or
filler composition 32 fills root canals 16 such that root canals 16
and lateral canals 22 are sealed off from each other and opening
24. Sealing root canals 16 and lateral canals 22 help prevent
bacteria and other microbes from entering root canal 12 or lateral
canals 22 and spreading infection or decay within tooth root
14.
In general, any polymerizable material capable of sealing a root
canal can be used with the present invention. Examples of suitable
primary polymerizable resins include a wide range of acrylic acid-
and methacrylic acid-containing compounds, acrylates,
methacrylates, alkylhydroxy methacrylates, alkylamino
methacrylates, epoxy-based compositions, cationic-based
compositions, and derivatives thereof. More specific examples of
polymerizable materials include glycidyl dimethacrylate, 2-hydroxy
ethyl methacrylate, 3-hydroxy propyl methacrylate, 4-hydroxy butyl
methacrylate, triethylene glycol dimethacrylate, and polyethylene
glycol dimethacrylate. An example of an epoxy-based endodontic
sealant resin that can be catalyzed using activating endodontic
points or tools according to the invention is AH 26, available from
Dentsply.
In one exemplary embodiment, the polymerizable resin includes an
oxyphosphorus alkyl methacrylate, such as bis glycerol
dimethacrylate phosphate. Examples of other oxy-phosphorus alkyl
methacrylates within the scope of the invention include bis
2-hydroxy ethyl methacrylate phosphate, phosphate ester of
p-hydroxyphenyl methacrylamide, phosphate ester of 3-hydroxy propyl
methacrylate, and phosphate ester of 4-hydroxy butyl methacrylate.
The oxyphosphorus group increases the adhesiveness and water
solubility (i.e., hydrophilicity) of the resulting resin.
One or more additional (or diluent) monomers can be added to
achieve the desired properties of initial flowability, curability,
and final cured strength and hardness. Diluent monomers suitable
for use in the present invention include urethane dimethacrylate,
p-hydroxyphenyl methacrylamide, butane diol dimethacrylate, and
bisphenol-A-diglycidyl dimethacrylate ("Bis-GMA").
The primary polymerizable resins are preferably included in a
concentration ranging from about 1% to about 90% by weight of the
composition, more preferably from about 10% to about 80% by weight,
and most preferably from, about 20% to about 70% by weight of the
composition.
The diluent monomers may be included in amounts of up to about 95%
by weight of the composition, preferably in a range from about 10%
to about 80%, and more preferably in a range from about 30% to
about 70% by weight of the composition.
The filler and sealer compositions may include other components or
adjuvents as desired to yield compositions having desired
properties. Examples include fillers, such as radiopaque fillers,
and non-chemically triggered curing initiators that do not
themselves initiate polymerization or cross linking absent
application of an appropriate curing stimulus (e.g., light or
heat). Thus, in addition to being chemical curable, the filler or
sealer compositions may be heat curable, photo curable, dual
curable, or use any other curing process or combination of curing
processes to initiate or accelerate curing.
In the case of chemical and dual curable sealer or filler
compositions, the curing system typically includes two or more
parts that are initially kept separate but which are mixed together
to initiate curing. In a conventional chemical or dual cure system,
one part of the system includes constituents of the resin sealer or
filling together with one part of the chemical cure system (e.g.,
one or more peroxide compounds), while another part includes
constituents of the resin sealing with the other half of the
chemical cure system (e.g., an amino compound). The present
invention deviates from such systems in one of several ways. In a
first embodiment, a single component chemical curable composition
is provided that includes only one part of a two-part chemical cure
system. The other part of the two-part chemical cure system is
provided by the curing composition, as discussed above, and
introduced into the curable composition in concentrated form by
means of an implement coated or impregnated with the curing agent
comprising the other part of the curing system. In this way, curing
is not initiated until an activating implement coated or
impregnated with the curing agent contacts with the curable
composition.
Alternatively, curing of a chemical or dual cure composition may
already have begun but can be accelerated using an activating
implement. According to one embodiment, a two-part chemical cure
composition is provided and mixed together prior to placement into
the root canal, except that a deficient amount of one part of the
curing system is provided so that only partial or slow curing of
the composition occurs. Curing of the composition may thereafter be
accelerated by introducing an additional quantity of the initially
deficient part of the curing system (i.e., curing agent) by means
of the activating implement or substrate.
The curable compositions may be cured in ways other than by
chemical curing. For example, in one type of dual cure composition,
a photoinitiator is included in order to permit photocuring of at
least an upper or more exposed portion of the curable composition
within a root canal. Examples of photoinitiators that may be used
within the scope of the invention include camphor quinone, benzoin
methyl ether, 2-hydroxy-2-methyl-1-phenyl-1-propanone, diphenyl
2,4,6-trimethylbenzoyl phosphine oxide, benzoin ethyl ether,
benzophenone, 9,10-anthraquinone, and derivatives thereof.
When included, photoinitiators are preferably included in an amount
in a range from about 0.05% to about 5% by weight of the
composition, more preferably in a range from about 0.1% to about 2%
by weight, and most preferably in a range from about 0.2% to about
1% by weight of the composition. In the case of a photocurable
sealer or filling composition, the polymerizable resin is
advantageously stable in the presence of the photoinitiator absent
the application of radiant energy.
IV. METHODS OF USING CURING COMPOSITIONS AND ACTIVATING IMPLEMENTS
TO CONTROL CURE TIME OF AN ENDODONTIC FILLER OR SEALER
The endodontic points and dental tools of the present invention can
be advantageously used in an endodontic procedure to control the
cure times of the endodontic sealer or filler composition. FIGS.
1-4 illustrate a tooth in various steps of an endodontic
procedure.
As discussed above, FIG. 1 shows tooth 10 with root canal 12 that
has been prepared using known endodontic techniques. In FIG. 2,
master endodontic points 28a and 28b are placed in root openings
20a and 20b respectively. To ensure that endodontic points or cones
28a and 28b form a reliable seal within openings 20a and 20b, a
procedure involving "tug back" is preferably performed. One of
ordinary skill in the art of endodontics will know when there is
sufficient tug back to confirm an adequate seal of the apexes 18a
and 18b by master endodontic cones 28a and 28b. Sufficient tug back
indicates that the fit between the gutta percha cone and the apex
is sufficiently tight to adequately seal the apex and prevent flow
of sealer or filling material into the surrounding bone tissue.
In a preferred method for placing a resinous sealer or filling
material within a root canal, FIG. 3 depicts syringe 30 having a
narrow diameter cannula 34 attached to tip 36 of syringe 30 used to
insert sealer or filling material into root canal 12. Due to the
narrow opening of the cannula 34, and because typical sealer or
filling materials are often viscous, it can be advantageous for
syringe 30 to be attached to a high pressure hydraulic injection
system. Examples of high pressure hydraulic syringes or systems are
set forth in U.S. Pat. No. 6,425,885, which is assigned to
Ultradent, Inc. Examples of narrow cannulas sized for entry into a
root canal are set forth in U.S. Pat. No. 6,079,979, which is
assigned to Ultradent Products, Inc. For purposes of disclosing
hydraulic pressurizing systems and cannulas sized to fit within a
root canal, the foregoing patents are incorporated herein by
reference.
The tip of the cannula 34 is initially placed within the root canal
12 near one of the apexes 18a or 18b and sealer or filling material
32 (FIG. 4) is injected into root canal 12. As the resinous
material begins and continues to fill up the root canal portion
16b, the cannula 34 is slowly raised or withdrawn. This manner of
filling the root canal 12 with resinous material minimizes or
eliminates the formation of air pockets or bubbles as the resin is
progressively placed within the root canal 12. This procedure
greatly improves the ability of the resin to initially purge most
or all of the air from within the root canal 12. As shown in FIG.
4, accessory points 38a and 38b are inserted into root canal 12 to
seal the root and/or deliver sealing material 30. One or both
accessory points 38a and 38b can be treated with a curing agent to
initiate or accelerate curing.
In an alternative embodiment, the sealer or filler composition is
placed in root canal 12 by first dipping the endodontic points in a
resin and then inserting the point into the root canal. When the
endodontic point is dipped, resin is coated thereon and is carried
into the root canal with the endodontic point. In one embodiment,
some or all of the sealer or filler composition is introduced into
the root canal using a master cone. In addition, or alternatively,
some or all of the sealer of filler composition can be introduced
into the root canal using one or more accessory cones.
Some or all of the endodontic cones can be treated to initiate
curing. In the case where the master cone is used to introduce the
sealer or filler composition into the root canal, the accessory
cones may be treated with a curing agent and used to initiate
curing. In the case where the accessory cones are used to introduce
the sealer or filler composition into the root canal, the master
cone may be treated so as to initiate curing after insertion of the
composition-laden accessory cone(s).
Controlling the curing time of an endodontic sealer or filling
material according to the present invention is accomplished by
either (i) selecting when to place an activating implement, such as
endodontic point or dental tool, in the curable sealer or filling
material, and/or (ii) selecting an activating endodontic point or
dental tool with a predetermined amount or concentration of curing
agent.
The first aspect of controlling curing according to the present
invention enables a practitioner to delay curing of the sealer or
filler composition by choosing when to place the activating
implement in contact with the sealer or filler composition 32. In
the exemplary embodiments illustrated in FIGS. 1-4, accessory
endodontic points or cones 38a and 38b are used by the practitioner
to control curing of the endodontic sealer or filler composition.
In this embodiment, sealer or filler composition 32 contains little
or no of the curing agent needed to initiate curing when it is
placed in the root canal. In addition, the master endodontic cones
28a and 28b are not activating and therefore do not initiate or
accelerate curing. Thus, the practitioner can have any amount of
time to place the sealer or filler material 32. In addition, the
practitioner has time to perform other desired procedures. For
example, the practitioner can take X-rays of tooth 10 to determine
whether the master endodontic points 28a and 28b have properly
sealed the apex and/or whether the sealer or filler material has
been properly placed in root canal 12 and/or lateral canals 22.
According to one embodiment, an activating implement is form in
situ by dipping a substrate into a microdose container containing a
small amount of a concentrated curing composition. An exemplary
microdose container 50 is depicted in FIG. 5A. The container 50
includes an elongate chamber 52 that has an interior diameter that
accommodates insertion therein of an endodontic cone 54 (e.g.,
gutta percha) or other similarly sized implement (not shown) that
can be inserted into a root canal. A lid 56 is provided for
initially sealing the curing composition prior to use. Wings 58 may
be provided to enhance grip and control of the relatively small
sized container 50 by the practitioner. The lid 56 may be a screw
cap that is able to screw over corresponding threads of the
container 50. As shown in FIG. 5B, the activating implement is
formed by removing lid 56 and inserting endodontic cone 54 or other
implement into the elongate chamber in order to coat the surface of
the endodontic cone 54 or other implement with the curing
composition.
Once the practitioner has completed or performed, the desired
dental procedures, an activating implement is inserted into the
root canal in order to initiate or accelerate curing of the sealing
resin contained in the root canal. By way of example, activating
accessory endodontic points 38a and 38b can be placed in root canal
12 as shown in FIG. 6. The curing agent coated on or impregnated
within accessory endodontic points 38a and 38b comes into contact
with the sealer or filler composition and initiates curing. Because
the practitioner has already had time to perform necessary
procedures, sufficient curing agent can be included such that
accessory points 38a and 38b cause sealer or filling material 32 to
cure very rapidly. The accessory points can be made according to
any of the methods described above. For example, the accessory
points can be pre-coated or impregnated during manufacture, or they
can be activated just prior to use.
In an alternative embodiment, a dental tool such as syringe 30 can
be used to initiate or increase curing of the sealer or filler
material. For, example, during an endodontic procedure, when the
practitioner desires to have the sealer or filling agent cured, the
practitioner can dip a syringe cannula 34 in a curing material and
then place the coated syringe in contact with the sealer or filler
composition.
In another alternative embodiment, the activating dental tool can
be an endodontic file or other narrow gauge structure that is able
to be inserted at least partially into a root canal.
In yet another alternative embodiment, the activating dental tool
can be an implement or substrate that is simply a piece of plastic
or other material that is made activating by applying a curing
agent thereto. At least a portion of the plastic or other material
is sized and configured to be placed in the root canal of a person
or animal such that it can be inserted into the root canal and
placed in contact with the sealer or filler composition.
In some cases, the circumstances of the procedure will determine
which activating endodontic point or dental tool the practitioner
will use. One advantage of a dental tool such as a piece of plastic
is that it can be used at anytime without regard to its use in the
dental procedure. In contrast, placement of an endodontic point is
sometimes determined according to the needs of the procedure.
However, using an activating endodontic point can be advantageous
because the endodontic point is intended to permanently remain in
the cured product.
V. KITS FOR USE IN CONTROLLING CURE TIMES
In order to further assist a practitioner in controlling cure times
of an endodontic filler or sealer composition, one or more of
several possible kits can be provided. It is within the scope of
the invention to provide curing compositions having differing
concentrations and/or amounts of curing agent in order to provide
different cure times. Thus, according to one exemplary embodiment,
a kit for use in initiating or accelerating curing of an endodontic
filler or sealer composition may include one or more microdose
containers, each containing an appropriate quantity and/or
concentration of curing composition. In this embodiment, a dental
practitioner can select an appropriate composition from the kit and
dip an implement or substrate into the curing agent composition so
as to form the activating implement or substrate just prior to use.
The dental practitioner can control the cure time by selecting the
proper curing agent composition.
In an alternative embodiment, one or more containers (e.g.,
microdose containers) containing one or more different quantities
and/or concentrations of curing composition are provided together
with one or more implements (e.g., gutta percha cones and/or rigid
elongated devices, such as narrow plastic or metal rods, able to
fit into a root canal). The one or more implements may be coated
and/or impregnated with the curing composition by the practitioner
just prior to inserting an implement within a filler or sealer
composition placed within a root canal to initiate and/or
accelerate curing thereof.
In another embodiment, kits within the scope of the invention may
include one or more endodontic filler or sealer compositions and
one or more microdose containers that contain appropriate amounts
and/or concentrations of curing composition (e.g., to provide
single or variable cure times). The endodontic filler or sealer
composition may be pre-packaged within an appropriate container,
such as a syringe. One or more syringe tips containing a cannula
sufficiently narrow to be placed within a root canal may optionally
be provided with the kit. The curing composition may include, as
the "curing agent", one part of a multi-part curing system. The
filler or sealer compositions may include another part of the
multi-part curing system complementary to the curing agent within
the curing composition. They may also comprise two-part chemical
cure compositions that include a deficient amount of curing agent
when mixed so that only slow or incomplete curing occurs. The
curing composition is then used to merely accelerate rather than
initiate curing. Such kits may optionally include one or more
implements as previously discussed.
In an alternative embodiment, kits may be provided that include a
plurality of implements that are pre-coated or impregnated with a
curing agent. In one embodiment, the implements may include
different amounts of curing agent so as to provide different cure
times. The kit may include endodontic cones that are intended to be
sequentially placed into a root canal during a filling or sealing
procedure. In such case, one or more cones that are to be placed
first may include an amount of curing agent that only initiates
slow curing of the filler or sealer composition. One or more cones
that are to be placed later may include an amount of curing agent
that more rapidly cures the filler or sealer composition.
For example, a kit containing one or more master cones and one or
more accessory cones can be used to select when or how fast to
initiate the curing process. According to one embodiment, the
master cone may be treated with a curing agent to initiate either
slow or fast curing. Accessory cones designed to be placed into a
root canal after the master cone can be treated with a curing
agent. In the case where the master cone is treated to initiate
slower curing one or more accessory cones can be used to initiate
faster curing. In some cases only the accessory cones will be
treated such that the master cone does not itself initiate
curing.
According to one embodiment, the plurality of activating endodontic
points and/or dental tools can have different concentrations of the
curing agents and are included in a kit. The endodontic points or
dental tools have different concentrations of curing agent that
correspond to different cure times. During an endodontic procedure,
the dental practitioner can select an activating endodontic point
or dental tool that provides the proper cure time for that
particular procedure.
During an endodontic procedure, those skilled in the art will know
how much time they will need before the sealer or filler
composition hardens. The present invention provides the
practitioner with the ability to select any desired curing time
during the procedure. If the practitioner needs 1 minute, 10
minutes, 2 hours or any other amount of time, the practitioner can
select an activating endodontic point or dental tool with a curing
agent in a concentration that provides the desired cure time.
According to one embodiment, the endodontic filling or sealing
composition will be a chemical cure composition having an initial
cure time of about 15 minutes or more (e.g. EndoREZ.RTM., which is
sold by Ultradent Products, Inc.). The activating implements are
preferably formulated so as to reduce the cure time to about 5
minutes or less.
In addition to providing controlled timing, the activating
endodontic points and dental tools of the present invention can
provide convenience. For example, a practitioner may want to use an
activating master endodontic point even though curing would begin
as soon as the sealer or filler composition is placed in the root
canal. In this embodiment, the practitioner can eliminate the need
to mix the sealer or filler composition, thus making the endodontic
procedure more convenient. Furthermore, the practitioner can be
provided with a set of activating endodontic points that give the
practitioner a selection of different concentrations of curing
agent and thus different cure times.
The present invention is also not limited with respect to use of a
single activating endodontic point or dental tool during an
endodontic procedure. For example, an activating master endodontic
point can be used with an activating accessory endodontic point.
The master endodontic point can initiate relatively slow curing and
the accessory endodontic point can be used to accelerate curing. In
yet another embodiment, a master endodontic point, an accessory
endodontic point, and/or a dental tool can be used to cure the
sealer or filling material. Each activating point or tool can be
coated and/or impregnated with the same or differing concentrations
of curing agent and can be placed in contact with the same or
different portions of the sealer or filling material.
The present invention also includes using more than one type of
curing system. For example, a chemical curing system can be used in
conjunction with a heat curing system or a light curing system.
Those skilled in the art will recognize the many different
combinations of curing systems that can be used with the foregoing
teachings of the present invention.
The following examples provide specific formulas of exemplary
embodiments of the present invention and should be considered as
illustrative of the present invention and not limiting in any
way.
VI. EXAMPLES
The following are examples provided in order to further assist one
of skill in the art in practicing the invention. They are given
only by way of example and should not be construed as being the
only way to practice the invention. One of skill in the art can
modify or enhance any of the following examples as needed to yield
a composition or activating implement having any desired
property.
Example 1
Acrylate Resin Coating
In Examples 2-5, below, a curing agent is diluted in an acrylate
resin coating. The coating provides for better adhesion between the
curing agent and a gutta percha cone. Diluting the curing agent in
the acrylate resin also gives the coating a desired cure time. The
acrylate resin coating used in the formulas of examples 2-5 is
prepared by first preparing a prepolymer mixture according to the
following formula:
TABLE-US-00001 Krasol LBH 2000 (linear polybutadiene 80.499%
polymer with hydroxyl end groups) Dabc LBH 2000 (tin catalyst)
0.001% Desmodur W bis(4-isocynotocyclohexyl) methane 19.500%
The prepolymer formed using the foregoing components is used to
form an acrylate resin coating according to the following
formula:
TABLE-US-00002 Prepolymer 2.5% 2-hydroxyethyl acrylate 2.5%
Polyethylene glycol diacrylate 70.8%
The prepolymer and the 2-hydroxyethyl acrylate are allowed to react
to completion and are then directly mixed with the polyethylene
glycol diacrylate to form the Acrylate Resin Coating. In each of
Examples 2-5, an endodontic point was coated or impregnated with
the curing composition and then placed in an acrylate-based sealer
or filler composition in order to initiate curing. The
acrylate-based sealer or filler composition included benzoyl
peroxide as an initiator. The amount of sealer or filler
composition used in the study was similar to the amount that would
occupy a typical root canal.
Example 2
A curing composition used to coat an endodontic cone was made by
mixing together the following components:
TABLE-US-00003 Acrylate Resin Coating 37.5% Triethylene glycol
dimethacrylate 37.0% P-TIDE (amine curing agent) 25.0% IRGACURE (a
photoinitiator) 0.5%
An endodontic cone made from gutta percha was coated or impregnated
with the foregoing curing composition. The curing composition was
solidified using light initiated curing. The coated endodontic cone
was placed into a quantity of filler or sealer composition
constituting a typical amount found within a root canal. The amine
curing agent caused the sealer or filler composition to cure in
about 2 minutes at 37.degree. C.
Example 3
A curing composition used to coat an endodontic cone was made by
mixing together the following components:
TABLE-US-00004 Acrylate Coating 97.5% DMPT 2.0% Irgacure 0.5%
An endodontic cone made from gutta percha was coated or impregnated
with the foregoing curing composition. The curing composition was
solidified using light initiated curing. The coated endodontic cone
was placed into a quantity of filler or sealer composition
constituting a typical amount found within a root canal. The amine
curing agent caused the sealer or filler composition to cure in
about 8 minutes at 37.degree. C.
Example 4
A curing composition used to coat an endodontic cone was made by
mixing together the following components:
TABLE-US-00005 Acrylate Resin Coating 98.0% P-TIDE 1.5% Irgacure
0.5%
An endodontic cone made from gutta percha was coated or impregnated
with the foregoing curing composition. The curing composition was
solidified using light initiated curing. The coated endodontic cone
was placed into a quantity of filler or sealer composition
constituting a typical amount found within a root canal. The amine
curing agent caused the sealer or filler composition to cure in
about 18 minutes at 37.degree. C. The activating endodontic cone
made according to this example gave inconsistent results.
Example 5
A curing composition used to coat an endodontic cone was made by
mixing together the following components:
TABLE-US-00006 Toluene 90.0% P-TIDE 10.00%
An endodontic cone made from gutta percha was impregnated with the
foregoing composition by briefly immersing the endodontic cone in
the solution and then allowing the solvent to volatize. The
endodontic cone was then placed in the sealer or filler
composition, which caused curing in about 3 minutes at 37.degree.
C. The P-TIDE degraded over time, thus reducing the effectiveness
of the activating endodontic cone over a period of several
months.
Example 6
An endodontic cone was impregnated with the following curing
composition by immersing the endodontic cone in the composition.
The endodontic cone was placed in a sealer or filler composition,
which accelerated to initial curing time from 15 minutes to 5
minutes at 37.degree. C.
TABLE-US-00007 TEG-DMA 74.9% P-TIDE 25% BHT 0.1%
Example 7
An endodontic cone is impregnated with the following curing
composition by immersing the endodontic cone in the composition.
The endodontic cone is placed in a sealer or filler composition in
order to accelerate curing.
TABLE-US-00008 TEG-DMA 74.9% DMPT 25% BHT 0.1%
Example 8
An endodontic cone was impregnated with the following curing
composition by immersing the endodontic cone in the
composition.
TABLE-US-00009 TEG-DMA 49.97% P-TIDE 50.00% Methyl Hydroquinone
(stabilizer) 0.03%
The endodontic cone was placed into EndoREZ and was able to
accelerate the curing time from 15-30 minutes down to 3-5
minutes.
Example 9
An endodontic cone was impregnated with the following curing
composition by immersing the endodontic cone in the
composition.
TABLE-US-00010 TEG-DMA 24.97% P-TIDE 75.00% Methyl Hydroquinone
(stabilizer) 0.03%
The endodontic cone was placed into EndoREZ and was able to
accelerate the curing time from 15-30 minutes down to 3-5
minutes.
Example 10
An endodontic cone was impregnated with the following curing
composition by immersing the endodontic cone in the
composition.
TABLE-US-00011 TEG-DMA 24.97% DMPT 75.00% Methyl Hydroquinone
(stabilizer) 0.03%
The endodontic cone was placed into EndoREZ and was able to
accelerate the curing time from 15-30 minutes down to about 3
minutes.
Example 11
An endodontic cone was impregnated with the following curing
composition by immersing the endodontic cone in the
composition.
TABLE-US-00012 TEG-DMA 49.97% DMPT 50.00% Methyl Hydroquinone
(stabilizer) 0.03%
The endodontic cone was placed into EndoREZ and was able to
accelerate the curing time from 15-30 minutes down to about, 3
minutes.
The present invention may be embodied in other specific forms
without departing from its spirit or essential characteristics. The
described embodiments are to be considered in all respects only as
illustrative and not restrictive. The scope of the invention is,
therefore, indicated by the appended claims rather than by the
foregoing description. All changes which come within the meaning
and range of equivalency of the claims are to be embraced within
their scope.
* * * * *