U.S. patent application number 14/247567 was filed with the patent office on 2015-02-12 for root canal filling materials and methods.
This patent application is currently assigned to SONENDO, INC.. The applicant listed for this patent is Morteza Gharib, Erik Hars. Invention is credited to Morteza Gharib, Erik Hars.
Application Number | 20150044630 14/247567 |
Document ID | / |
Family ID | 38779181 |
Filed Date | 2015-02-12 |
United States Patent
Application |
20150044630 |
Kind Code |
A1 |
Gharib; Morteza ; et
al. |
February 12, 2015 |
ROOT CANAL FILLING MATERIALS AND METHODS
Abstract
In various embodiments of a method for filling root canal
spaces, the root canal spaces are cleaned and irrigated, for
example, by any suitable endodontic procedure, and the irrigating
liquid is not removed from the canal spaces prior to filling. In
some embodiments, a hydrophobic filler material is introduced into
the root canal spaces while they are filled with liquid. As the
canal spaces are filled, the hydrophobic filler material displaces
the liquid and drives it out of the canal spaces, towards the crown
of the tooth, where it can be removed. The hydrophobic filler
material may comprise magnetically responsive particles having a
hydrophobic surface coating that are compacted into the root canal
spaces by application of a magnetic force field. In other
embodiments, hydrophilic filler material in a flowable phase is
introduced into the canal spaces where it partly displaces and
partly absorbs the irrigating liquid before solidifying.
Inventors: |
Gharib; Morteza; (San
Marino, CA) ; Hars; Erik; (Mission Viejo,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Gharib; Morteza
Hars; Erik |
San Marino
Mission Viejo |
CA
CA |
US
US |
|
|
Assignee: |
SONENDO, INC.
Laguna Hills
CA
|
Family ID: |
38779181 |
Appl. No.: |
14/247567 |
Filed: |
April 8, 2014 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
12900852 |
Oct 8, 2010 |
|
|
|
14247567 |
|
|
|
|
11752812 |
May 23, 2007 |
7833016 |
|
|
12900852 |
|
|
|
|
60802662 |
May 23, 2006 |
|
|
|
Current U.S.
Class: |
433/81 ;
433/224 |
Current CPC
Class: |
A61K 6/17 20200101; A61K
6/56 20200101; A61K 6/20 20200101; A61L 27/04 20130101; A61C 5/62
20170201; A61L 27/34 20130101; A61K 6/20 20200101; A61L 27/34
20130101; C08L 83/04 20130101; C08L 83/04 20130101; C08L 83/04
20130101; A61L 2430/12 20130101; A61K 6/54 20200101; A61C 5/50
20170201 |
Class at
Publication: |
433/81 ;
433/224 |
International
Class: |
A61C 5/04 20060101
A61C005/04; A61C 5/06 20060101 A61C005/06 |
Claims
1. (canceled)
2. (canceled)
3. (canceled)
4. (canceled)
5. (canceled)
6. (canceled)
7. (canceled)
8. (canceled)
9. (canceled)
10. (canceled)
11. (canceled)
12. (canceled)
13. (canceled)
14. A method for filling a root canal of a tooth, the method
comprising: supplying a first filling material to the tooth, the
first filling material comprising large particles that are larger
than an apical opening of the tooth; plugging a portion of a root
canal of the tooth near an apex with the first filling material;
and at least substantially filling the remainder of the root canal
with a second filling material.
15. The method of claim 14, wherein the second filling material
comprises small particles that are smaller than the apical opening
of the tooth.
16. The method of claim 15, wherein the second filling material
also comprises particles larger than the apical opening.
17. The method of claim 14, further comprising curing the first
filling material or the second filling material.
18. The method of claim 14, further comprising applying a
non-contacting force field to the first filling material to cause
the first filling material to move through the root canal.
19. The method of claim 18, wherein applying the non-contacting
force field comprises applying a magnetic field to the first
filling material, at least a portion of the first filling material
responsive to the magnetic field.
20. A root canal filler for a tooth, the filler comprising: a first
filling material comprising a plurality of particles that are
larger than an apical opening of the tooth, the particles
configured to plug a portion of a root canal proximate an apex of
the tooth; and a second filling material having a plurality of
particles that are smaller than the apical opening of the tooth,
the second filling material configured to at least substantially
fill the remainder of the root canal.
21. The filler of claim 20, wherein the first filling material is
different from the second filling material.
22. The filler of claim 20, wherein at least some of the large
particles or the small particles comprise a ferromagnetic core
substantially surrounded with a hydrophobic coating.
23. The filler of claim 20, wherein the large particles are in a
range from about 35 microns to about 200 microns.
24. The filler of claim 20, wherein the small particles are in a
range from about 2 microns to about 30 microns.
25. A method for filling a root canal of a tooth, the method
comprising: positioning a force generator at or near the tooth;
supplying a filling material to the tooth; and activating the force
generator to generate a time-varying force in the filling material
in the tooth, the time-varying force causing the filling material
to substantially fill the root canal of the tooth.
26. The method of claim 25, wherein the time-varying force
comprises a magnetic force field.
27. The method of claim 26, wherein the filling material comprises
particles including a magnetic core.
28. The method of claim 25, wherein the time-varying force
comprises a non-contacting force.
29. The method of claim 25, wherein activating the force generator
comprises generating temporal and/or spatial variations in a force
field to control the forces applied to the filling material.
30. The method of claim 25, further comprising generating the
time-varying force to control the degree of filling in the
tooth.
31. The method of claim 25, further comprising generating the
time-varying force to prevent the filling material from reaching or
passing through an apical opening of the tooth.
32. The method of claim 25, wherein activating the force generator
comprises causing the filling material to fill portions of the root
canal that are remote from the force generator.
33. The method of claim 25, further comprising propagating acoustic
energy through the root canal to substantially clean the root
canal.
34. The method of claim 33, wherein propagating acoustic energy
comprises activating a liquid jet.
35. The method of claim 25, further comprising causing the filling
material to harden in the tooth.
36. The method of claim 25, further comprising monitoring a status
of the filling of the root canal.
37. The method of claim 36, further comprising adjusting the force
generator to alter the time-varying force field in response to the
monitoring of the status of the filling.
38. The method of claim 37, wherein adjusting the force generator
comprises altering at least one of a force field intensity and a
force field gradient to enhance the control of the filling.
39. The method of claim 25, wherein supplying the filling material
to the tooth comprises supplying a first filling material and a
second filling material to the tooth, the first filling material
different from the second filling material.
40. A system for filling a root canal space of a tooth, the system
comprising: a device for holding a filling material, the filling
material configured to flow through the root canal space to
substantially fill the root canal space; and a force generator
sized and shaped to be disposed at or near the tooth during a
filling procedure, the force generator configured to generate a
time-varying force in the filling material when the filling
material flows through the root canal space, the time-varying force
causing the filling material to substantially fill the root canal
of the tooth.
41. The system of claim 40, further comprising the filling
material.
42. The system of claim 40, wherein the force generator comprises a
manipulator.
43. The system of claim 42, wherein the manipulator comprises one
or more magnets, and wherein the time-varying force comprises a
magnetic force field.
44. The system of claim 40, wherein the force generator is
configured to cause the filling material to fill portions of the
root canal space that are remote from the force generator.
45. The system of claim 40, wherein the device for holding the
filling material comprises a needle.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 12/900,852, filed Oct. 8, 2010, entitled "ROOT
CANAL FILLING MATERIALS AND METHODS," which is a divisional of U.S.
patent application Ser. No. 11/752,812, filed May 23, 2007,
entitled "ROOT CANAL FILLING MATERIALS AND METHODS," which claims
the benefit under 35 U.S.C. .sctn.119(e) of U.S. Provisional Patent
Application No. 60/802,662, filed May 23, 2006, entitled "ROOT
CANAL FILLING MATERIALS AND METHODS," the entire disclosure of each
of which is hereby incorporated by reference herein in its
entirety.
BACKGROUND
[0002] 1. Field
[0003] The present disclosure relates generally to filling spaces
in a body location and more particularly to filling root canal
spaces in a tooth.
[0004] 2. Description of the Related Art
[0005] Treatment of root canal spaces in a tooth typically involves
removal of organic material from the root canal spaces followed by
filling the spaces with a filling material. Present filling
materials are hydrophobic and may include gutta-percha, polymers,
calcium hydroxide (Ca(OH).sub.2), and/or zinc oxide (ZnO) liners.
Prior to filling the root canal spaces with these filling
materials, the canal spaces typically must be widened, which is
traditionally performed with hand- or machine-driven endodontic
files. To ensure proper adhesion of the filling material to tooth
dentin, moisture and fluids are evacuated from the canal spaces
(such as by wicking or aspirating) prior to filling. Such
evacuation of fluids commonly results in sucking organic components
and contaminated fluids (e.g., pus, serum, and/or blood) from the
apical periodontium through one or more canal orifices, which may
cause re-infection of the canal spaces. Due to these and other
deficiencies, the overall success rate for the treatment is around
70 percent. Because of the uncertainty and the cost of the process,
extraction of the diseased tooth is often used as a treatment
alternative.
SUMMARY
[0006] An embodiment of an apparatus comprises a manipulator which
produces a non-contacting force field to manipulate a filling
material during filling of a root canal space of a tooth. The
filling material may comprise a plurality of particles responsive
to the non-contacting force field. In some embodiments, the
non-contacting force field may comprise a magnetic field.
[0007] An embodiment of a method for filling a root canal space of
a tooth comprises using a non-contacting force field to manipulate
a filling material during filling of the root canal space. In some
implementations, the non-contacting force field comprises a
magnetic field, and the filling material magnetically interacts
with the magnetic field.
[0008] An embodiment of a method of filling a root canal system of
a tooth comprises compacting colloidally suspended discrete
particles in a root canal to fill the canal with a substantially
solid filling.
[0009] An embodiment of a root canal filler for a tooth comprises a
multiplicity of relatively large particles sized to form a plug in
a canal space proximate an apex of the tooth and a multiplicity of
relatively small particles sized to at least substantially fill the
remainder of the canal space.
[0010] An embodiment of a method for filling a root canal space of
a tooth comprises plugging a canal space proximate an apex of the
tooth and subsequently at least substantially filling remaining
space of the canal with a flowable filling material.
[0011] An embodiment of a hydrophilic root canal filling material
is provided. The filling material may be adapted to be introduced
into a root canal space when liquid is in the canal space during
filling. The liquid may provide a barrier against migration of
bacteria into an apical area of the tooth. When introduced into the
root canal, at least a substantial portion of the liquid may be
absorbed by the hydrophilic material.
[0012] An embodiment of a method of filling a root canal space of a
tooth comprises introducing a hydrophobic material into a root
canal space of a tooth when a liquid substantially fills the root
canal space. The liquid may provide a barrier against migration of
bacteria into an apical area of the tooth. The liquid may be
substantially displaced from the root canal space by the
hydrophobic material.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a cross section schematically illustrating a
typical human tooth, which in this example is a molar.
[0014] FIG. 2A schematically illustrates an embodiment of an
endodontic treatment for filling the root canal spaces of the
tooth.
[0015] FIG. 2B is a cross-section view schematically showing an
example endodontic method for cleaning a root canal system of a
tooth, in which a high-velocity jet is directed toward a dentinal
surface through an opening in the crown of the tooth.
[0016] FIG. 3 schematically illustrates an embodiment of a
micromanipulator comprising a stylus having a magnetic tip. FIG. 3
schematically depicts example magnetic field lines near the
tip.
[0017] FIG. 4 schematically illustrates a root canal filling method
using the micromanipulator of FIG. 3 to magnetically guide
magnetically responsive filler material into the canal spaces of a
tooth.
[0018] FIG. 5 schematically illustrates another embodiment of a
filling method using a matrix of electromagnetic coils to produce a
magnetic field gradient near a tooth (shown in the inset).
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0019] The present disclosure describes various materials and
methods for endodontic treatments that overcome possible
disadvantages associated with conventional root canal treatments.
In certain embodiments of a method for filling root canal spaces,
the root canal spaces are cleaned and irrigated (e.g., by any
suitable endodontic procedure), and the irrigating liquid is not
removed from the canal spaces prior to filling. In certain such
embodiments, the method comprises introducing a hydrophobic filler
material into the root canal spaces while they are filled with
liquid (e.g., water). As the canal spaces are filled, the
hydrophobic filler material displaces the liquid and at least
partially drives the filler material out of the canal spaces,
towards the crown of the tooth, as will be described more fully
below.
[0020] In some embodiments, the hydrophobic filler material
comprises a colloid of coated ferromagnetic particles (and/or other
material that is responsive to a magnetic field). The coating
advantageously may comprise a substantially hydrophobic substance.
By way of example, the coating may comprise polyorganosiloxanes,
polyorganosilanes, or mixtures thereof. For convenience, the
magnetically responsive particles will be referred to hereinafter
as "mag-particles."
[0021] FIG. 1 is a cross section schematically illustrating a
typical human tooth 10, which comprises a crown 12 extending above
the gum tissue 14 and at least one root 16 set into a socket
(alveolus) within the jaw bone 18. Although the tooth 10
schematically depicted in FIG. 1 is a molar, the material and
methods described herein may be used on any type of tooth such as
an incisor, a canine, a bicuspid, or a molar. The hard tissue of
the tooth 10 includes dentin 20 which provides the primary
structure of the tooth 10, a very hard enamel layer 22 which covers
the crown 12 to a cementoenamel junction 15 near the gum 14, and
cementum 24 which covers the dentin 20 of the tooth 10 below the
cementoenamel junction 15.
[0022] A pulp cavity 26 is defined within the dentin 20. The pulp
cavity 26 comprises a pulp chamber 28 in the crown 11 and one or
more root canal spaces 30 extending toward an apex 32 of each root
16. The pulp cavity 26 contains dental pulp, which is a soft,
vascular tissue comprising nerves, blood vessels, connective
tissue, odontoblasts, and other tissue and cellular components. The
pulp provides innervation and sustenance to the tooth through the
epithelial lining of the pulp chamber 26 and the root canal space
30. Blood vessels and nerves enter/exit the root canal space 30
through a tiny opening, the apical foramen 34, near a tip of the
apex 32 of the root 16.
[0023] FIG. 2A schematically illustrates one embodiment of an
endodontic treatment for filling the canal spaces 30 of the tooth
10. A drill or grinding tool is initially used to make an opening
40 in the tooth 10. The opening 40 may extend through the enamel 22
and the dentin 20 to expose and provide access to pulp in the pulp
cavity 26. The opening 40 may be made in a top portion of the crown
12 of the tooth 10 (as shown in FIG. 2A) or in another portion such
as a side of the crown 12 or in the root 16 below the gum 14. The
opening 40 may be sized and shaped as needed to provide suitable
access to the pulp cavity 26 and/or all of the canal spaces 30. In
some treatment methods, additional openings may be formed in the
tooth 10 to provide further access to the canals 30 and/or to
provide dental irrigation.
[0024] The pulp cavity 26 and/or the canal spaces 30 may be cleaned
and irrigated by any suitable method. For example, in some
procedures, endodontic files are inserted into the root canal
system to open the canal spaces 30 and remove organic material
therein. An effective method for cleaning the root canal system is
depicted in FIG. 2B, which schematically illustrates a high
velocity collimated jet 52 of liquid (e.g., water) directed through
the opening 40 toward a dentinal surface 54 of the tooth 10. In
some embodiments, the high-velocity liquid jet may have a velocity
in a range from about 50 m/s to about 300 m/s and may have a
transverse size (e.g., diameter) in a range from about 1 micron to
about 1000 microns.
[0025] Impact of the jet 52 causes acoustic energy to propagate
from the impact site on the dentinal surface 54 through the entire
tooth 10, including the root canal system. The acoustic energy is
effective at detaching substantially all organic material in the
root canal system from surrounding dentinal walls. The acoustic
energy may be effective at cleaning the root canal system, because
the acoustic energy generates acoustic cavitation effects (e.g.,
cavitation bubbles, cavitation jets, acoustic streaming,
entrainment, etc.), which efficiently detach and/or delaminate
organic material from dentinal surfaces and tubules. The treatment
time during which the high-velocity jet 52 is directed toward the
tooth 10 may range from about 1 second to about 120 seconds in
various cleaning methods.
[0026] In many embodiments, the detached organic material can be
flushed from the root canal using an irrigation fluid (e.g.,
water). In some embodiments, liquid from the high-velocity jet
provides the irrigation fluid. In other embodiments, a low-velocity
jet or stream provides the irrigation fluid. The liquid jet 52 may
be directed from a handpiece 50 that can be manipulated within a
patient's mouth by a dental practitioner. In certain endodontic
procedures, the high velocity liquid jet 52 is directed into the
pulp cavity 26 and/or the root canal spaces 30 to excise and/or
emulsify organic material therein. The liquid jet 52 may be
generated by a high pressure compressor system or by a pump system
in various embodiments. Further details of apparatus and methods
for generating the high velocity jet 52 and using the jet 52 to
clean root canal systems are found in U.S. patent application Ser.
No. 11/737,710, filed Apr. 19, 2007, entitled "Apparatus and
Methods for Treating Root Canals of Teeth," which is hereby
incorporated by reference herein in its entirety.
[0027] In certain preferred embodiments, after cleaning the canal
spaces 30, irrigating liquid 42 (e.g., water) is not removed from
the canal spaces 30 prior to filling. The irrigating liquid 42
advantageously may act as a vector for any floating particles
and/or organic material and as a barrier against the influx of
periapical fluid (e.g., through the apical opening 34). Filling
material 44, such as the hydrophobic filling material described
herein, may then be applied to the canal spaces 30. As the canal
spaces 30 are filled, the hydrophobic filler material 44 displaces
the irrigating liquid 42 and forces the liquid 42 at least
partially out of the canal spaces 30, toward the opening 40 in the
crown 12 of the tooth 10 (or toward any other suitable opening
formed in the tooth 10).
[0028] In certain embodiments, the filler material 44 comprises a
sterile colloid comprising mag-particles. The filler material 44
may be provided to a dental practitioner in standard 1.8 milliliter
dental cartridges. In a preferred embodiment schematically
illustrated in FIG. 2A, the colloid is applied to the canal spaces
30 using a standard cartridge syringe with an injection needle 50
such as, for example, a sterile disposable 30-gauge short injection
needle. In some procedures, the colloid is applied into the canal
spaces 30 without pressure and without binding the injection needle
50 to the walls of the canal space 30, which advantageously may
reduce application of pressure to the liquid 42 present in the
canal space 30 and may allow the liquid 42 to be displaced from and
escape the canal space 30. In the example method depicted in FIG.
2A, the needle 50 has been used to apply the filler material 44 to
a portion of the canal space 30a. After filling the canal space
30a, the dental practitioner may fill other spaces in the tooth 10,
such as the canal space 30b. Although depicted as straight in FIG.
2A, the needle 50 may be bent and/or curved to access portions of
the canal spaces 30a, 30b. In some embodiments, portions of the
needle 50 may be flexible.
[0029] In certain embodiments, a force field is used to manipulate
the filler material during the filling of the canal spaces 30. The
force field advantageously may be a non-contacting force field that
applies a force to the filler material without physically
contacting the material. For example, the force field may comprise
a magnetic force field, and the filler material may comprise a
substance that is responsive to the magnetic force field.
[0030] As schematically illustrated in FIG. 3, the magnetic force
field may be applied using a micromanipulator comprising a stylus
60 having a magnetic tip 62. FIG. 3 schematically depicts example
magnetic field lines 64 near the tip 62. In other embodiments, the
magnetic field lines 64 may have a different configuration and/or
polarity than shown in FIG. 3. For example, the magnetic field
lines 64 may have a configuration that includes components such as
dipole, quadripole, and/or higher order multipole components. In
some methods for filling root canal spaces, the magnetic tip 62 of
the stylus 60 is positioned near the tooth 10 and moved toward the
apex 32 adjacent to the tooth root 16. FIG. 4 schematically
illustrates application of the tip 62 of the stylus 60 to the canal
space 30a of the tooth 10. The magnetic tip 62 may be moved toward
the apex 32 one or more times during a treatment. The magnetic
field of the tip 62 may provide an attractive force that urges the
mag-particles in the canal space 30a towards the apex 32 until
substantially all the canal space 30a is filled, and the
mag-particles are condensed in the canal space 30a. As the
mag-particles are condensed, the liquid 42 in the canal spaces 30
is squeezed outward due to the hydrophobic surface property of the
coating material of the mag-particles. This procedure may be
repeated for the canal space 30 in each root 16 of the treated
tooth 10. Surplus colloid can be removed from the access opening 40
and coronal pulp chamber 28.
[0031] In some methods, the mag-particles are also condensed in the
canal spaces 30 using an endodontic spreader such as, for example,
a No. 1 dental hand-spreader and/or plugger (e.g., a. Schilder
spreader) so as to form a substantially solid core 70 of
mag-particles in the canal spaces. The substantially solid core 70
is schematically illustrated in the canal space 30b shown in FIG.
4. The resulting core 70 advantageously may be substantially
bacterio-static, substantially tissue compatible, and not
substantially affected by tissue metabolism. The core 70 of
mag-particles also may be substantially radio-opaque. The filled
canal spaces 30 may be sealed over in a conventional manner, such
as with a bonded restorative material.
[0032] In certain preferred embodiments, mag-particles of different
sizes are used in the filling process. In order to reduce the
likelihood that mag-particles migrate through the apical opening 34
of the tooth 10 into surrounding vascularized tissue, larger
mag-particles may be introduced first into the canal spaces 30,
followed by introduction of smaller mag-particles. The larger
mag-particles advantageously may have a size that allows the
mag-particles to migrate proximate to the apical opening 34, but
not through the apical opening 34. The magnetic tip 62 of the
stylus 60 may be used to assist condensing the larger and/or the
smaller mag-particles in the canal spaces 30. In certain
embodiments, the mag-particle coating is somewhat compliant such
that the coatings can deform as magnetic attraction from the stylus
60 pulls them through the root canal towards the apex 32 and into
progressively smaller spaces. It is beneficial if the coating is
not so compliant as to deform to a size smaller than that of the
apical opening 34 (typically, 30 microns). As an example, in
certain embodiments, the size of the larger mag-particles may be in
a range from about 35 to about 200 microns, more preferably in a
range from about 40 to 100 microns, and even more preferably in a
range from about 50 to 70 microns. The larger mag-particles may
thus advantageously be used to form a plug in a portion of the root
canal space 30 adjacent the apex 32 of the tooth 10. The
mag-particles forming the plug may be compacted using the magnetic
field of the stylus 60 and may bond to each other by diffusion of
the coating material.
[0033] In certain preferred embodiments, following creation of the
plug comprising the larger mag-particles, smaller size
mag-particles are introduced into the canal spaces 30. By way of
example, the size of the smaller mag-particles may be in a range
from about 2 to 30 microns, more preferably in a range from about 2
to 15 microns, and even more preferably in a range from about 2 to
5 microns. In certain such preferred embodiments, the mag-particles
are sufficiently small to readily fill the small side canals, fins,
and narrow spaces that typically extend laterally from the main
root canal spaces 30. In some methods, the smaller mag-particles
are compacted by means of the magnetic field and bond to each other
by diffusion of the coating materials, thereby creating a rigid
volume of filling material that fills the root canal system.
[0034] Various micromanipulators may be utilized to magnetically
guide the mag-particles to targeted sites using magnetic force
fields. Embodiments of the micromanipulator may use a magnetic
force to guide the mag-particles by application of an attractive
force, a repulsive force, and/or a combination thereof to pull
and/or to push the mag-particles toward the targeted sites. In some
embodiments, the micromanipulator is configured to provide a
suitable magnetic force gradient to guide the mag-particles. By way
of example, the micromanipulator may comprise a stylus (such as the
stylus 60 described above) having a tip 62 that comprises one or
more magnets or electromagnets. The one or more magnets may
comprise rare earth (e.g., neodymium) magnets. In another
embodiment, the micromanipulator comprises a plurality of coils
forming a matrix of electromagnets. When suitably energized, the
electromagnetic matrix of coils creates temporal and/or spatial
electromagnetic field variations (statically or dynamically) to
provide electromagnetic field patterns and field gradients that
increase or optimize the force (and/or force gradient) applied to
the mag-particles. The force gradient may be used to control the
degree of mag-particle compactness and also to prevent the filler
material 44 from reaching unwanted areas (e.g., the apical opening
34).
[0035] In certain treatment embodiments, some of the mag-particles
are guided by the micromanipulator to assist moving surrounding
filling material into small cracks, holes, crevices, channels,
and/or spaces in the root canal system. For example, movement of
the mag-particles may cause some of the surrounding fluid and/or
filler material to flow due to a coupling force between the
mag-particles and the fluid and/or filler material. The coupling
force may comprise, for example, friction, viscosity, etc. In some
methods, a time varying force field (and/or force gradient) is
applied to the mag-particles to cause such a flow. The fluid
motions induced by the movement of the mag-particles may assist
introduction of filler material into the smaller root canal
spaces.
[0036] In some embodiments, the electromagnetic matrix is in the
form of a strip 80 that is mounted on the head of the patient with
the electromagnetic matrix in proximity to the apex of the tooth or
teeth under treatment, as illustrated schematically in FIG. 5. The
matrix may be powered by a power-supply that is controlled by a
computer or microprocessor. The power supply drives the matrix of
coils selectively under the control of computer software to create
a magnetic-field gradient in the manner of a magnetic phased array.
As schematically depicted in FIG. 5, the magnetic field gradient
may be configured to provide a positive region 84 of attractive
magnetic field to the root canal system, while providing a negative
region 88 of zero or repulsive magnetic field near the apical
openings 34 of the tooth 10 under treatment. The matrix may be
spatially calibrated to the location of the apical openings 34, so
that the field gradient generated by the matrix is precisely
located with respect to the tooth 10 under treatment and draws the
mag-particles through the canal system, but not through the apical
openings 34. Accordingly, the electromagnetic matrix may preferably
be attached to the patient in a manner that prevents or inhibits
relative motion between the matrix and the tooth 10 under treatment
when the magnetic field is applied. Such attachment may be
accomplished by means of a helmet (e.g., for upper teeth), a jaw
clamp (e.g., for lower teeth), or by clamping the matrix to one or
more teeth adjacent the tooth 10 under treatment.
[0037] The matrix of coils may be used not only to move the
mag-particles, but also to sense movement of the mag-particles. For
example, as the mag-particles fill the root canal system, the
mag-particles will cross magnetic field lines produced by the
matrix, which generates a direct current (DC) in the coils. By
measuring the DC current (and/or voltage) in each coil, relative
movement between the mag-particles and the tooth 10 under treatment
may be calculated. In some embodiments, the relative motion of the
mag-particles is output on a display for viewing by the dental
practitioner. In such embodiments, the dental practitioner may
observe in real-time the migration of the mag-particles into the
root canal system and the mag-particles' location relative to the
apical openings 34. To provide increased control over the filling
treatment, the magnetic field intensity, gradient, spatial and/or
temporal configuration may be altered in accordance with the sensed
movement. In an alternative embodiment, the matrix of coils
provides a low intensity field for sensing movement without moving
the particles, and the magnetic field that moves the particles is
applied by a micromanipulator such as a handheld stylus manipulated
by the dental practitioner (e.g., the stylus 60 shown in FIG.
3).
[0038] In some methods, after the filler material 44 comprising the
mag-particles has sufficiently cured, energy is applied to heat the
filler material 44 above the melting point to at least partially
liquefy the filler material 44 and/or the mag-particles. The
applied energy may comprise electric, magnetic, and/or
electromagnetic energy such as, for example, from an applied
electric field and/or magnetic field. In some embodiments, the
applied energy comprises electromagnetic energy (e.g., ultrasound).
The at least partially liquefied material may then solidify into a
substantially solid core within the root canal system of the
treated tooth.
[0039] In some cases, it may be desirable for the substantially
solid core of mag-particles to be removed (e.g., for re-treatment
of the tooth 10). In some treatment methods, the core may be at
least partially liquefied by application of energy to the affected
tooth. As described above, the applied energy may comprise
electric, magnetic, and/or electromagnetic energy. For example,
ultrasound energy may be applied, e.g., with a Cavitron.RTM.
instrument available from Dentsply International, York, Pa. The
liquefied core material can be suctioned or irrigated out of the
canal spaces 30.
[0040] In other embodiments of methods for filling root canal
spaces, the filling material may comprise a hydrophilic material
such as, for example, a protein-based, reversible hydrocolloid.
Protein-based reversible hydrocolloids are thermoplastics, which
may liquefy in a temperature range above about 80 to 95 degrees
centigrade and may solidify in a temperature range below about 40
to 45 degrees centigrade. Liquefaction and solidification
temperature ranges may be different in different hydrocolloids.
When in a liquid phase, reversible hydrocolloids may be able to
absorb several times their volume of water. To avoid substantial
changes in the physical properties of the hydrocolloid, in some
methods water absorption is limited to about 30% of the volume of
the hydrocolloid. Advantageously, the filling material may further
comprise at least one bacterio-static substance, as well as at
least one substance to provide radio-opacity. The filling material
may comprise both a hydrophobic material (e.g., mag-particles) and
a hydrophilic material (e.g., a reversible hydrocolloid) in some
embodiments.
[0041] In certain method embodiments, the hydrophilic filling
material is supplied in sealed 1.8 ml dental cartridges suitable
for use in dental syringes. To liquefy the filling material, the
cartridges may be placed in a heated liquid (e.g., hot or boiling
water) for a liquefaction time that is about 10 minutes for some
hydrocolloids. After the filling material is sufficiently
liquefied, the cartridge can be placed in a cartridge syringe
fitted with a suitable needle, for example, a 30 gauge short
needle.
[0042] To deliver the filling material to the root canal system,
the needle may be curved and/or bent to access the canal spaces 30
in the tooth 10 under treatment. In certain preferred embodiments,
the needle is placed without binding into the canal space 30, and a
suitable amount of liquefied filling material is injected into the
space 30 to partially absorb and/or partially displace liquid in
the canal space 30. It may be desirable in some embodiments for
enough water from the canals 30 to be displaced such that no more
than about 30% of the water is absorbed by the hydrocolloid filler
(e.g., at least about 70% of the water is displaced). By
introducing a suitable amount of liquid reversible hydrocolloid
into the canal spaces 30, the hydrocolloid may help maintain the
liquid stage of filler material previously introduced into the
canal spaces 30, may help maintain application of pressure, and
thereby may help transport the filler material to the apex 32 and
to substantially all the canal spaces 30 before the filler material
solidifies. The filled canal spaces 30 may be sealed over in a
conventional manner with a bonded restorative material.
[0043] As described above, in some methods, after the filler
material has sufficiently cured, energy is applied to heat the
filler material toward or above the melting point to at least
partially liquefy the filler material (and/or mag-particles if
used). The at least partially liquefied material may help fill the
canal spaces 30 and may help provide a substantially uniform core
of material in the root canal system. The applied energy may
comprise electric, magnetic, and/or electromagnetic energy such as,
for example, from an applied electric and/or magnetic field. In
some embodiments, the applied energy comprises electromagnetic
energy (e.g., ultrasound). The at least partially liquefied
material may then solidify into a substantially solid core within
the root canal system of the treated tooth.
[0044] Although the tooth 10 depicted in the figures is a molar,
one of ordinary skill in the art will appreciate that the
procedures may be performed on any type of tooth such as an
incisor, a canine, a bicuspid, or a molar. Also, the disclosed
methods are capable of filling root canal spaces having a wide
range of morphologies, including highly curved root canal spaces
which are difficult to fill using conventional dental techniques.
Moreover, the disclosed methods may be performed on human teeth
(including children's teeth) and/or on animal teeth.
[0045] The foregoing description sets forth various preferred
embodiments and other illustrative but non-limiting embodiments of
the inventions disclosed herein. The description provides details
regarding combinations, modes, and uses of the disclosed
inventions. Other variations, combinations, modifications,
equivalents, modes, uses, implementations, and/or applications of
the disclosed features and aspects of the embodiments are also
within the scope of this disclosure, including those that become
apparent to those of skill in the art upon reading this
specification. Additionally, certain objects and advantages of the
inventions are described herein. It is to be understood that not
necessarily all such objects or advantages may be achieved in any
particular embodiment. Thus, for example, those skilled in the art
will recognize that the inventions may be embodied or carried out
in a manner that achieves or optimizes one advantage or group of
advantages as taught herein without necessarily achieving other
objects or advantages as may be taught or suggested herein. Also,
in any method or process disclosed herein, the acts or operations
making up the method/process may be performed in any suitable
sequence and are not necessarily limited to any particular
disclosed sequence. Accordingly, the scope of each of the
inventions disclosed herein is to be determined according to the
following claims and their equivalents.
* * * * *