U.S. patent application number 10/300061 was filed with the patent office on 2003-04-10 for system and method for whitening teeth.
Invention is credited to Downs, Robert J. JR., Zavitsanos, Peter D..
Application Number | 20030068601 10/300061 |
Document ID | / |
Family ID | 25535274 |
Filed Date | 2003-04-10 |
United States Patent
Application |
20030068601 |
Kind Code |
A1 |
Zavitsanos, Peter D. ; et
al. |
April 10, 2003 |
System and method for whitening teeth
Abstract
A teeth whitening system includes a heating module, a mouthpiece
thermally connected to the heating module such that heat can be
transferred to the mouthpiece, and a thermocatalytically activated
whitening gel positioned in the mouthpiece such that the gel
contacts a user's teeth, whereby when heat is transferred from the
heating module to the mouthpiece, the gel is activated by heat,
metal surface catalysis, and water or saliva to whiten the user's
teeth.
Inventors: |
Zavitsanos, Peter D.;
(Gwynedd Valley, PA) ; Downs, Robert J. JR.;
(Gwynedd Valley, PA) |
Correspondence
Address: |
John F. Letchford
Klehr, Harrison, Harvey,
Branzburg & Ellers
260 South Broad Street
Philadelphia
PA
19102
US
|
Family ID: |
25535274 |
Appl. No.: |
10/300061 |
Filed: |
November 20, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10300061 |
Nov 20, 2002 |
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09989611 |
Nov 21, 2001 |
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6497575 |
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09989611 |
Nov 21, 2001 |
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09815501 |
Mar 23, 2001 |
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60192213 |
Mar 27, 2000 |
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Current U.S.
Class: |
433/215 ;
433/32 |
Current CPC
Class: |
A61C 19/066 20130101;
A61C 19/063 20130101 |
Class at
Publication: |
433/215 ;
433/32 |
International
Class: |
A61C 005/00; A61C
003/00 |
Claims
What is claimed is:
1. A teeth whitening system, comprising: a heating module; a
mouthpiece thermally connected to said heating module such that
heat can be transferred from said heating module to said
mouthpiece; and a heat-activated whitening gel positioned in said
mouthpiece such that said gel contacts a user's teeth, whereby when
heat is transferred from said heating module to said mouthpiece,
said gel is activated and whitens the user's teeth.
2. A teeth whitening system according to claim 1, wherein said
heating module includes a heat sink and an insulation layer
surrounding said heat sink, whereby said insulation layer maintains
the temperature of said heat sink.
3. A teeth whitening system according to claim 2, wherein said
mouthpiece includes a metallic connector passing through said
insulation layer and contacting said heat sink, thereby creating
the thermal connection between said heat sink and said
mouthpiece.
4. A teeth whitening system according to claim 3, wherein said
heating module is electrically powered and controlled.
5. A teeth whitening system according to claim 4, wherein said
connector includes a first thermocouple and said heat sink includes
a second thermocouple, whereby said first thermocouple and said
second thermocouple act together to regulate the temperature of
said mouthpiece.
6. A teeth whitening system according to claim 3, wherein said
insulation layer includes a first portion and a second portion,
said first portion and said second portion being releasably
connected; and said heat sink is affixed to said first portion such
that when said first portion and said second portion are separated,
a portion of said heat sink is exposed, whereby said heat sink can
be heated to an operating temperature.
7. A teeth whitening system according to claim 3, wherein said
mouthpiece includes a metallic substructure attached to said
connector; and a molded tooth form surrounding said substructure,
said tooth form transferring heat to the user's teeth from said
heat sink through said connector and to said metallic substructure,
said tooth form preventing the user's teeth from contacting said
metallic substructure.
8. A teeth whitening system according to claim 7, wherein said
mouthpiece is removably connected to said heating module.
9. A teeth whitening system according to claim 7, wherein said
tooth form is sized and shaped to fit at least one of the upper set
of teeth and the lower set of teeth of the user.
10. A teeth whitening system according to claim 7, wherein said
tooth form is made of plastic.
11. A teeth whitening system according to claim 7, wherein said
tooth form is made of molded foam.
12. A teeth whitening system according to claim 11, wherein the
molded foam in an open cell, porous foam.
13. A mouthpiece for use in a teeth whitening system, comprising: a
substructure; a connector attached to said substructure, said
connector sized and shaped to interface with the teeth whitening
system; and a molded tooth form attached to said substructure
opposite said connector.
14. A mouthpiece according to claim 13, wherein said substructure
is made of metal.
15. A mouthpiece according to claim 14, wherein said substructure
has a rough surface, thereby enhancing the chemical reactions that
cause the teeth to whiten.
16. A mouthpiece according to claim 14, wherein said substructure
is coated with a catalyst, thereby enhancing the chemical reactions
that cause the teeth to whiten.
17. A mouthpiece according to claim 13, wherein said substructure
is made of a metal composite.
18. A mouthpiece according to claim 17, wherein said substructure
has a rough surface, thereby enhancing the chemical reactions that
cause the teeth to whiten.
19. A mouthpiece according to claim 17, wherein said substructure
is coated with a catalyst, thereby enhancing the chemical reactions
that cause the teeth to whiten.
20. A mouthpiece according to claim 13, wherein said tooth form is
sized and shaped to fit at least one of the upper set of teeth and
the lower set of teeth of a user.
21. A mouthpiece according to claim 13, wherein said tooth form is
made of molded foam.
22. A mouthpiece according to claim 21, wherein the molded foam is
an open cell, porous foam.
23. A method for whitening teeth, comprising the steps of:
providing a heat-conducting mouthpiece; applying a heat-activated
whitening gel to the mouthpiece; connecting the mouthpiece to a
heat source; and inserting the mouthpiece into a mouth of a user,
whereby heat flows from the heat source to the mouthpiece, where
the heat activates the whitening gel to whiten the user's
teeth.
24. The method of claim 23, wherein the applying step includes
moistening the mouthpiece with water prior to applying a
non-hydrous or hydrous whitening gel.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation-in-part application relating to U.S.
application Ser. No. 09/815,501 filed Mar. 23, 2001, which is a
.sctn.111(a) application relating to U.S. application Ser. No.
60/192,213 filed Mar. 27, 2000 (now abandoned).
FIELD OF THE INVENTION
[0002] The present invention relates to a system and method for
whitening teeth, and, more particularly, to a system and method
employing the use of heat and a delivery system which provides
catalytic action thus accelerating the action of a bleaching
medium.
BACKGROUND OF THE INVENTION
[0003] Whiter teeth are desired for cosmetic reasons, and several
processes to accomplish this have been described in the prior art.
These processes have always included the use of bleaching gels or
solutions containing various concentrations of hydrogen peroxide
(H.sub.2O.sub.2) or carbamide peroxide (CH.sub.6N.sub.2O.sub.3),
which on an equal molar basis contains 35% H.sub.2O.sub.2 (by
weight) which is released from activation by water or other sources
such as heat or light. The degree of whitening provided by these
processes increases with (a) peroxide concentration, (b) time of
contact between the reacting species of peroxide and the tooth
enamel surface, (c) diffusion rate into the dentine layer, (d) a
favorable structure (texture) of tooth surface, and most
importantly, (e) the rate of activation of the gel in terms of
generating available peroxide (H.sub.2O.sub.2) and/or its reactive
species (OH and O). Due to its chemical structure, the peroxide
must produce transient species such as OH and O before the final
products, H.sub.2O and O.sub.2, are generated by the following
mechanism, 2 H.sub.2O.sub.2.fwdarw.4
OH.fwdarw.2H.sub.2O+20.fwdarw.2H.sub.2O+O.sub.2. The presence of
these active transient species (radical OH and atomic oxygen O)
play the most important role in the whitening process due to their
higher reactivity. In other words, two peroxide molecules must
break down to four OH molecules, which react to produce two water
(H.sub.2O) molecules and two atoms of oxygen. The final step is the
recombination of atomic oxygen into molecular oxygen.
[0004] In most cases, tooth whitening is accomplished with custom
fitted plastic trays filled with bleaching gels (known as "take
home trays") which are worn for one to several hours a day or
overnight over extended periods of time such as several weeks or
months before a satisfactory level of whitening is realized. Gel
activation by light from laser sources or arc lamps in several
regions of the electromagnetic spectrum, including infrared,
visible, and ultraviolet, have been introduced with various and
ambiguous levels of success due to: (a) lack of fundamental
understanding of the mechanism involved in the whitening process,
(b) lack of control in terms of the density of delivered energy,
(c) the fraction of the energy absorbed by gel or absorbed by
teeth, (d) shadowing effects, and (e) the necessity for prolonged
periods of treatment if one tooth is treated at a time. (See, e.g.,
U.S. Pat. Nos. 4,952,143 and 4,661,070.)
[0005] Furthermore, some of the peroxide concentrations used (from
15% up to 30% H.sub.2O.sub.2) require effective gum isolation in
order to prevent tissue burns. There is also a lack of information
on the temperature that is generated by the light source and lack
of temperature control. These factors can lead into gum burns,
tooth sensitivity after the treatment, and possible long-term
effects that are presently unknown.
[0006] Another method, U.S. Pat. No. 4,983,381, involves the use of
applying heat directly to the teeth with a thermocube or plate,
which covers the teeth. This method is difficult to implement and
requires soft tissue isolation and protection due to high
concentrations of H.sub.2O.sub.2 (30-70%) as well as requiring many
steps and high temperatures (up to 55.degree. C.). This design is
also problematic because its close fit on the teeth does not allow
enough volume for whitening gel. It also requires custom made
plates (upper and lower arches) for each person.
[0007] Still another method, U.S. Pat. No. 5,927,981, utilizes a
high temperature chamber for producing a high temperature
(60.degree. C.). In this method, a bleaching vapor is directed to
the teeth from the chamber. This process is difficult to implement
and exposes the recipient to unnecessary safety risks due to both
the tooth pulp and the gums (if not isolated) being exposed to high
temperatures. In addition, its whitening effectiveness is uncertain
and further complicated by the fact that the transient species OH
and O may no longer be present in the "bleaching vapor" when it
reaches the teeth due to the length of travel.
[0008] The present invention provides a process which has the
following advantages over the prior art: (a) lower peroxide
concentrations (16% to 20% carbamide or 5 to 10% H.sub.2O.sub.2);
(b) no gum isolation is required; (c) within one hour it can
provide up to eleven shades of improvement, depending on age and
level and type of coloration; (d) it provides greater comfort to
recipient than take home trays or light activated whitening
procedures; (e) it requires less peroxide over the course of the
treatment than "take home trays;" and (f) it is safer than the
light activation methods, especially those using high intensity
lasers or other uncontrolled high intensity light sources,
including those in the blue portion of the spectrum.
[0009] It should also be pointed out that this invention will
accelerate the whitening process as well when the gel is confined
by dentist-made take home trays or current office bleaching
procedures which employ higher concentrations of hydrogen peroxide
(30%) with isolation.
SUMMARY OF THE INVENTION
[0010] The present invention provides a safe and effective way for
whitening teeth through a combination of new techniques, including
a balanced and controlled delivery of activated bleaching medium.
The present invention accelerates the action of the bleaching
medium by increasing (a) the gel temperature; (b) the concentration
of active peroxide species of the gel at the interface between the
tooth surface and the attached gel; (c) the reaction rate between
the active transient species (OH and O) of the peroxide and the
coloring compounds in the teeth; and (d) the diffusion rate of the
active species through the enamel. A heating wave is provided by a
controlled thermal source which allows the temperature of the gel
to reach a safe temperature range of 40.degree.-42.degree. C. on
the tooth surface. The heating is also controlled by a combination
of state of the art devices which control the temperature to
.+-.1.degree. C. or on a simpler approach by heat transfer.
[0011] In a first embodiment, the device includes a heating element
embedded into an aluminum (or other metal or conductive material)
cylinder referred to as a "heat sink" which is thermally insulated
from, the atmosphere with a plastic coating, highly insulating
Styrofoam composite, or other insulator. The temperature of the
heat sink is controlled and maintained at a level of
50.degree.-65.degree. C. so that a controlled, constant amount of
thermal energy flows into a mouthpiece. The mouthpiece is made from
metal, a metal matrix composite, or other thermally conductive
material. The mouthpiece preferably includes a metallic
substructure with a plastic/organic filler and a low conductivity
coating or an open cell foam cover.
[0012] The heat sink temperature is controlled so that the
temperature of the mouthpiece and the gel does not exceed a preset
level (about 41.degree. C..+-.1.degree.). In case this temperature
is exceeded in an electrically-powered embodiment, a safety
thermocouple at the base of the mouthpiece automatically shuts off
the power of the control box. For added safety, the heating element
is electrically insulated from its case by ceramic cement and the
case is also insulated from the heat sink by another layer of
cement. The exteriors of heat sink and the mouthpiece are further
insulated by plastic or Styrofoam coatings, thus providing a third
level of safety. In addition, the demand of electric current(of the
30 watt heater at 120V) is low and is limited to 0.25 amperes.
[0013] The increased effectiveness and speed of the whitening
process is due to the faster, generation and mobility of
H.sub.2O.sub.2 in the peroxide gel, the decomposition of
H.sub.2O.sub.2 to OH and O the enhanced diffusion rate into the
tooth as well as the enhancement of the reaction rate between the
active peroxide species (which can be radicals of OH or atomic
oxygen O) and the compounds on the enamel and dentine responsible
for the stains and coloration. It is the change in the molecular
state and bond structure (from double to single carbon bonds) of
the coloring compounds which accounts for the lighter color, as
well as the removal of stain compounds from the enamel surface.
[0014] The mouthpiece of the present invention is preferably made
of a metal matrix composite consisting of a high conductivity, high
heat-capacity metal skeleton (e.g., aluminum, copper, steel or
other conductive alloy) that is surrounded by or impregnated with
an open cell, porous, flexible foam. The mouthpiece may also be
covered with a perforated plastic material. One important feature
of this invention is based on the heat flow delivery from the heat
sink, which is kept in the range of 50.degree.-70.degree. C.
(depending on the relative size of heat sink to mouthpiece), to the
metal matrix composite and is designed so that the foam temperature
does not exceed levels of comfort or safety, which is in the
vicinity of 41.degree. C.
[0015] The method of the present invention controls the flow of
thermal energy from a heat sink in order to provide thermal
activation of bleaching gels. It accelerates the reaction of
peroxide active species with pathological and normal colorations
thus resulting in a faster whitening process via controlled heat
flow, enhanced catalytic H.sub.2O.sub.2 decomposition by the metal
mouthpiece and the fast transfer of reactionary ingredients through
the open cell foam to the teeth. The advantages of the proposed
methods are as follows: (a) temperature control at the base of the
mouthpiece ensures safety by protection from overheating higher
than 41.degree. C., which is an acceptable safe level; (b) the
conductive portion of the mouthpiece is isolated from the flesh of
the mouth and the teeth; (c) it allows use of gels with lower
peroxide concentrations which do not require protection and/or
isolation of the gums through the application of coatings, (d) it
works with a variety of hydrogen peroxide and/or carbamide peroxide
gels, both hydrous and non-hydrous, the latter being more
effective; (e) it provides a reservoir of peroxide sufficient to
last at least a 30-minute treatment, to be repeated two or three
times with new gel for best results; (f) the energy flow created by
the heat sink as well as the construction of the mouthpiece provide
the necessary balance required for the safety of the system; and
(g) the flexible foam allows one size to fit all and its open cell
structure allows easy transfer of more reactive species to travel
from the metal side of the mouthpiece, which is hotter, to the
tooth surface without raising the temperature of the tooth itself.
This non-equilibrium event allows for even faster whitening
results.
[0016] Other useful features of this invention include the fact
that the metal component of the mouthpiece does not require plaster
models to be made (to custom fit to the teeth) because it is large
enough to fit most, if not all, mouth sizes due to the rigid metal
front wall and the flexible foam or plastic back wall which
provides the desirable fit around the teeth of any size or
geometry. The construction of the mouthpiece is such that one
mouthpiece can treat both upper and lower teeth simultaneously. The
fact that the mouth is closed during treatment provides greater
comfort to the recipient of the treatment, as compared to other
methods based on light activation where the mouth is forced open
with a lip retractor during the entire procedure. For several
reasons (including safety and sanitary reasons), all or a portion
of the metal matrix mouthpiece is designed to be disposable, such
that it can be discarded at the end of the procedure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] For a better understanding of the present invention,
reference is made to the following detailed description of several
exemplary embodiments considered in conjunction with the
accompanying drawings, in which:
[0018] FIG. 1 is a block diagram of a first embodiment of a teeth
whitening instrument constructed in accordance with the present
invention;
[0019] FIG. 2 is a cross-sectional side view of a mouthpiece used
in connection with the various embodiments of the present
invention;
[0020] FIG. 3 is a top view, in partial cross-section, of an
alternate embodiment of the connection between the mouthpiece and
the heating module shown in FIG. 1;
[0021] FIG. 4 is a partial cross-sectional side view of a second
embodiment of a teeth whitening instrument constructed in
accordance with the present invention; and
[0022] FIG. 5 is a cross-sectional side view of a third embodiment
of a teeth whitening instrument constructed in accordance with the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0023] A first, electrically-powered embodiment of a teeth
whitening device 10 constructed in accordance with the present
invention is shown in FIG. 1. The device 10 includes a control box
12, which houses a power and has a rectangular shape with
sufficient room on the top or front side for several controls. An
on/off switch 14 is located on the top of the control box 12 and is
electrically connected to the power source. A replaceable fuse 16
is positioned inside the control box 12 and is electrically
connected between the switch 14 and a connector 18. The connector
18 is used to connect a power cord 20 of a heating module 22 to the
control box 12.
[0024] The heating module 22 consists of a case 24 having an outer
layer 26 made of thermal insulation. A cartridge heater 28 is
positioned inside the case 24 and is electrically connected to the
power cord 20. A safety control 30 is electrically connected to the
cartridge heater 28, in order to control the temperature of the
cartridge heater 28. A heat sink 32 is electrically connected to
the cartridge heater 28 such that the heat sink 32 retains heat
generated by the cartridge heater 28. The heat sink 32 is a
cylinder made of aluminum or other heat-conducting material which
surrounds the heating element of the cartridge heater 28. The heat
sink 32 is thermally insulated with an outer coating made of
plastic, an insulating Styrofoam composite, or other insulating
material.
[0025] A mouthpiece 34 is attached to the heating module 22 via a
connector 36 which also provides heat flow to the mouthpiece 34
from the heat sink 32. A thermocouple 38, mounted in the heat sink
32, and a thermocouple 40, located in the connector 36, act
together to regulate the temperature of the mouthpiece 34. If the
temperature of the heat sink 32 exceeds the preset temperature
range, the thermocouple 38 shuts off the power source in the
control box 12, thereby preventing the heat sink 32 from heating
further. Similarly, if the temperature of the mouthpiece 34 exceeds
its preset level, the thermocouple 40 shuts off the power source in
the control box 12, thereby preventing the mouthpiece 34 from
heating further.
[0026] In order to accurately control the temperature of the
mouthpiece 34, a number of controls are provided on the control box
12. The temperature of the heat sink 32 is indicated on a
temperature display 42 and is adjusted by a controller 44. The
temperature of the mouthpiece 34 is shown on a temperature display
46 and is pre-configured to approximately 41.degree. C. A safety
control 48, operating in conjunction with the safety control 30 in
the heating module 22, is used to maintain the temperature of the
mouthpiece 34 within a tolerance of .+-.1.degree. C., such that the
temperature of the mouthpiece 34 is within a range of
40.degree.-42.degree. C.
[0027] FIG. 2 shows details of the construction of the mouthpiece
34. The connector 36, which is removably attached at one end to the
heat sink 32, is fixedly attached at an opposite end to a metallic
substructure 60 that forms the "backbone" of the mouthpiece 34. The
connector 36 may be force-fit or friction-fit into the heat sink
32, or may be removably connected to the heat sink 32 by any
conventional means. Some illustrative examples of a removable
connection between the connector 36 and the heat sink 32 will be
described below in connection with FIG. 3. A tooth form 62,
composed of molded foam or plastic, surrounds the metallic
substructure 60 and is designed to transfer heat from the metallic
substructure 60 to a user's teeth.
[0028] The tooth form 62 can be constructed as fitting either the
upper or lower teeth only, or as fitting both the upper and lower
teeth simultaneously. In a preferred embodiment, the tooth form 62
is constructed of an open cell, porous foam. When in use, the tooth
form 62 is first moistened with water and a heat-activated gel 64
is placed in the tooth form 62, whereby the gel 64 coats the user's
teeth. The mouthpiece 34 can be manufactured to already include the
gel 64 in the tooth form 62; in such circumstances, a seal 66 is
provided around the tooth form 62 to retain the gel 64 therein and
to preserve the sterility of the mouthpiece 34.
[0029] In a preferred embodiment, the open cell foam used to make
the tooth form 62 provides a protective buffer for the user's teeth
and allows the reactive species of hydrogen peroxide to flow freely
between the metallic substructure 60 and the user's teeth. Water,
which is pre-applied to the tooth form 62, together with the user's
saliva acts to (i) enhance the conduction of heat from the tooth
form 62 to the gel 64, and (ii) break down a non-hydrous peroxide
gel. This process allows the gel 64 to be heated by the metallic
substructure 60 at higher temperatures (50.degree.-60.degree. C.)
than exist on the outside of the tooth form 62. The higher
temperatures and the presence of water increase the reactivity of
the peroxide gel and accelerates the whitening process.
[0030] The following discussion of the operation of the present
invention assumes that the mouthpiece 34 is attached to the
cartridge heater 28 and the seal 66, if present, has been removed.
First, the user inserts the mouthpiece 34 into his or her mouth,
with the tooth form 62 surrounding the teeth, permitting the gel 64
to coat the teeth. The user then moves the switch 14 to the "on"
position, which begins heating the heat sink 32 to a temperature of
between 75.degree.-80.degree. C. The heat is transferred from the
heat sink 32 to the metallic substructure 60, such that the tooth
form 62 is heated to a temperature of approximately 41.degree. C.
The safe temperature range for both the activation of the gel 64
and the safety of the user's teeth and gums is between
40.degree.-42.degree. C. At higher temperatures, there is a risk of
burning the user's gums. While the mouthpiece 34 is in position,
the user can place the case 24 on his or her chest (or through a
brace), so that the user does not have to hold the case 24 during
the entire length of the procedure. Another arrangement is to
position the mouthpiece perpendicular to the heat sink (i.e.,
attached to the side).
[0031] The gel 64 is of a type that has a low peroxide
concentration (e.g., 16% -20% carbamide or 5% -10% H.sub.2O .sub.2)
Either hydrous or non-hydrous peroxide gels can be used effectively
with the present invention. Improved results can be attained by
using a non-hydrous gel, because in addition to enhancing the
conduction of heat (increasing the reaction rate), the water
applied to the tooth form 62 mixes with and attacks the non-hydrous
peroxide gel 64, further accelerating the reaction rate and the
whitening process. Using a gel 64 having high viscosity and low
peroxide concentration avoids having to isolate the user's gums to
prevent burns.
[0032] The combination of the gel 64, the temperature of the
mouthpiece 34, and the time the mouthpiece 34 is worn
(approximately a total of one hour in 20 or 30-minute segments with
gel replacement), can provide up to eleven shades of whitening. The
increased effectiveness and speed of the whitening process is due
to the faster generation and mobility of H.sub.2O.sub.2 in the
peroxide gel 64 as well as the enhancement of the reaction rate
between the active peroxide species (which can be radicals of OH
and atomic oxygen O) and the compounds on the enamel and dentine
responsible for the stains and coloration. It is the change in the
molecular state and bond structure (from double to single carbon
bonds) of the coloring compounds in dentine which accounts for the
lighter color as well as the removal of staining substance from the
enamel surface.
[0033] One of the important features of the present invention is
the open cell structure of the foam on the tooth form 62 of the
mouthpiece 34, which allows some of the gel 64 to come into contact
with the metal substructure 60 of the mouthpiece 34, which, due to
the higher temperature of the metal, generates transient species of
OH and O at a faster rate than would otherwise be achieved without
contacting the metal. The open cell foam material can be attached
to the substructure 60 by blowing, molding, or bonding with an
adhesive.
[0034] The use of an open cell foam for the tooth form 62 is
important because the metal substructure 60 of the mouthpiece 34
maintains a higher temperature (between 50.degree.-60.degree. C.)
than the teeth can tolerate and therefore allows for a faster
generation of active ingredients at the interface between the metal
and the foam. The thermally generated active ingredients can flow
through the open cell foam to the teeth surface and provide a
faster bleaching action. This process is based upon a beneficial
non-equilibrium event since the active ingredients (OH and O) were
generated at a higher temperature than the temperature of the tooth
surface, thereby providing for enhanced whitening action without
discomfort or safety concerns due to the drop in temperature at the
exterior of the tooth form 62.
[0035] Applying water to saturate the open cell foam is important
for two reasons. First, the water acts as a heat conductor,
enhancing the reaction rate of the gel. Second, when a non-hydrous
peroxide gel is used, the water mixes with and attacks the gel to
generate the transient species faster. The water, which is
pre-applied to the open cell foam, acts together with the user's
saliva, the heat, and a non-hydrous peroxide gel to accelerate the
bleaching process. This process allows the use of more gel because
the reaction rate is increased, and as a result, the contact time
of the reactive species with the user's teeth is increased. Another
advantage of this device is based on the catalytic action of the
hot metal surface. The mouthpiece may have a rough aluminum surface
or may be coated with other metals such as platinum, palladium, and
other known catalysts which can catalytically enhance the
generation of active species even further.
[0036] The electrically-powered embodiment of the present invention
provides redundant controls in several ways in order to prevent
exposing the patient to higher temperatures than those which are
physiologically experienced by the body (such as fever or drinking
coffee), and to reduce the possibility of electric shock from the
heating element. The temperature of the mouthpiece 34 is monitored
and controlled by the two thermocouples 38, 40, which are located
in two different positions. The thermocouple 38 monitors the
temperature at the heat sink 32 and shuts off the power when the
preset temperature is exceeded and the thermocouple 40 monitors the
temperature at the front of the mouthpiece 34 and shuts off the
power if the temperature exceeds the safety zone, even by one
degree. The heating element of the cartridge heater 28 is
electrically isolated from the heat sink 32 by two layers of
insulation, preferably made of ceramic cement: one between the
electrically heated element and the exterior of the cartridge
heater 28, and another between the exterior of the cartridge heater
28 and the heat sink 32. The metallic substructure 60 of the
mouthpiece 34 is also insulated from direct contact with the human
flesh or teeth.
[0037] The advantages of the teeth whitening device 10 include: (a)
the thermocouple 40 in the connector 36 to the mouthpiece 34 helps
to prevent overheating the mouthpiece 34 higher than the preferred
41.degree. C. level; (b) the heating element of the cartridge
heater 28 is electrically isolated from the exterior of the case 24
and the exterior of the cartridge heater 28 is electrically
isolated from the heat sink 32; (c) the metallic substructure 60 of
the mouthpiece 34 is isolated from the flesh of the mouth and the
teeth; (d) the use of a variety of gels 64 with low peroxide
concentrations, which do not require protection and/or isolation of
the gums through the application of coatings; (e) providing a
reservoir of gel 64 sufficient to last throughout the process
(approximately one hour) without re-application of gel; and (f) the
energy flow created by the heat sink 32, as well as the
construction of the mouthpiece 34, provide safety balance.
[0038] Another exemplary embodiment of a mouthpiece constructed in
accordance with the present invention is illustrated in FIG. 3.
Elements illustrated in FIG. 3 which correspond to the elements
described above with respect to FIGS. 1 and 2 have been designated
by corresponding reference numerals increased by one hundred. The
embodiment of FIG. 3 is designed for use in the same manner as the
embodiment of FIGS. 1 and 2 unless otherwise stated.
[0039] Referring now to FIG. 3, an alternate configuration for
locking the mouthpiece 134 to the heating module 122 is shown. The
connector 136 has two portions: a first portion 136a fixedly
attached to the mouthpiece 134 and a second portion 136b fixedly
attached to the heating module 122. The first portion 136a and the
second portion 136b are releasably connected via a locking
mechanism 170. The locking mechanism includes a pin 172 biased by a
spring 174, both of which are mounted in the first portion 136a
opposite the mouthpiece 134. The pin 172 engages an opening 176 in
the second portion 136b to lock the first portion 136a within the
second portion 136b. To separate the first portion 136a from the
second portion 136b, the user pushes on the pin 172 to pass it
through the opening 176, which permits the first portion 136a to
slide within and relative to the second portion 136b. Being able to
separate the mouthpiece 134 from the heating module 122 allows the
mouthpiece 134 to be easily cleaned or discarded.
[0040] In addition to the locking mechanism 170, the mouthpiece 134
may be connected to the heating module 122 by any other
conventional means, such as, for example, inserting a set screw
through the opening 176 so that it engages the first portion 136a
or by threadedly connecting the mouthpiece 134 to the heating
module 122.
[0041] In addition to providing the heating by electrical means,
other heating mechanisms are also effective. These include: (a)
immersing the heat sink 32 in hot water (see the discussion in
connection with FIG. 4 below), (b) heating the heat sink 32 by
using a hot plate or other heating device that can be controlled
such that its temperature does not exceed 100.degree. C., (c)
heating the mouthpiece 34 by hot water through a hollow
construction of an appendix heat sink manually or with a pump, (d)
making the heat sink 32 out of a porous ceramic (or plastic) filled
with water and heating in a microwave oven, (e) preheating a
hermetically sealed mouthpiece 34 with gel 64 in hot water or in a
microwave oven, and (f) encapsulating an inorganic salt or other
material which changes phase from solid to liquid at warm water
temperatures 55.degree.-70.degree. C. into the heat sink. This
phase change process is endothermic and the process is reversed
during cooling, as the liquid converts into solid with the release
of the heat of fusion. This allows the heat sink to cool down
slower and thus mitigate the need for multiple heating steps during
the procedure.
[0042] These alternates may also be safely used by consumers in
their homes, as opposed to use by dental professionals in their
offices. The alternate designs of these devices provide the
advantages of lower cost heat activated teeth whitening without the
need for an electrically powered device, of a one hour procedure
and still whitening all teeth with a single mouthpiece, and no
tissue isolation.
[0043] An example of an embodiment of the present invention adapted
for home use is shown in FIG. 4. A teeth whitening device 200
includes a heating unit 202 and a mouthpiece 204 with a stem 206.
The mouthpiece 204 is attached to the heating unit 202 by the stem
206. The mouthpiece 204 is preferably constructed in the same
manner as the mouthpiece 34 shown in FIG. 2. The heating unit 202
has an upper portion 210 with an exterior insulating layer 212 and
a heat sink 214 attached to the interiors of the insulating layer
212. The stem 206 extends through the insulating layer 212 and
contacts the heat sink 214, which is made of a thermally conducting
material, such as aluminum. A lower portion 220 of the heating unit
202 is removably attached to the upper portion 210 and has an
insulating layer 222 and a hollow interior sized and shaped to
snugly fit around the heat sink 214. A temperature indicating strip
230 is affixed to the exterior of the heat sink 214 and displays
the temperature of the heat sink 214 when heated, as described in
greater detail below.
[0044] To heat the heat sink 214 to the desired operating
temperature, the lower portion 220 is detached from the upper
portion 210 of the heating unit 202, thereby exposing a portion of
the heat sink 214. In a separate container (e.g., a pot), water is
brought to a boil and the exposed portion of the heat sink 214 is
placed into the boiling water. In several minutes of such heating,
the heat sink 214 reaches a temperature of 90.degree.-100.degree.
C. At that point, the heating unit 202 is removed from the water
and the lower portion 220 is placed around the heat sink 214 and is
attached to the upper portion 210, completely insulating the heat
sink 214, so that the heating unit 202 is safe to handle. The
balance in heat flow from the heat sink 214 to the mouthpiece 204
is such that the gel temperature at the tooth surface does not
exceed 41.degree. C.
[0045] The heat sink 214 is heated to 90.degree.-100.degree. C. by
boiling water, hot plate, or other heating means. The temperature
of the heat sink 214 is indicated by the temperature indicating
strip 230 affixed to the heat sink 214. The temperature strip 230
changes color to indicate the change in temperature. When boiling
water is used as the heat source, the temperature of the heat sink
214 will not exceed 100.degree. C. So long as the initial
temperature of the heat sink 214 is between 90.degree.-100.degree.
C., the temperature of the metal substructure of the mouthpiece 204
will be between 50.degree.-60.degree. C. and the temperature of the
foam covering of the mouthpiece 204, which is the part of the
mouthpiece 204 that comes into contact with the user's teeth, will
be maintained at 40.degree.-41.degree. C.
[0046] Once the heat sink 214 reaches a temperature of between
90.degree.-100.degree. C., it is removed from the heating source,
inserted to the lower portion of the insulating cover, and is ready
to be used as part of the teeth whitening process. The mouthpiece
204 is then inserted into the heat sink 214, from which it draws
thermal energy. After assembly, the device 200 provides a steady,
controlled flow of heat to the mouthpiece 204. The flow of heat
from the heat sink 214 to the mouthpiece 204 is controlled by (i)
the temperature of the heat sink 214, (ii) the size of the heat
sink 214, (iii) the length and thickness of the connector 206, and
(iv) the surface area of the portion of the connector 206 that is
inserted into the heat sink 214. The temperature of the mouthpiece
204 is maintained within a tolerance of .+-.1.degree. C., such that
the temperature of the mouthpiece 204 is within a range of
40.degree.-42.degree. C., although in this version, the temperature
will continue to drop during treatment.
[0047] Depending on the thickness of the insulating layers 212, 222
surrounding the heat sink 214, the teeth whitening device 200 will
provide useful thermal activation for up to 20-30 minutes. The
heating process must be repeated two-three times, with new gel each
time, in order to provide an effective treatment. This embodiment
provides initial whitening and allows for "touch-up" treatments
perhaps two to three times a year.
[0048] FIG. 5 shows another alternate embodiment of the present
invention adapted for home use. A teeth whitening device 300
includes a lower portion 302 and an upper portion 304, which fit
together to form a closed container. A connector 306 extends
through the upper portion 304 and a mouthpiece 308 is fixed to one
end of the connector 306, external to the upper portion 304. The
lower portion 302 is formed as a hollow cylinder having an outer
insulating layer 310 made of Styrofoam or other insulating material
and an inner layer 312 made of plastic. The upper portion 304
includes an outer insulating layer 320 made of Styrofoam or other
insulating material and an inner layer 322 made of plastic. The
lower portion 302 and the upper portion 304 relate together such
that the respective inner layers 312, 322 form a single chamber
330.
[0049] To use the teeth whitening device 300, the upper portion 304
is separated from the lower portion 302, and the lower part of the
chamber 330 is filled with a liquid, such as water, water mixed
with sodium chloride, sodium acetate, or other microwaveable
liquid. The lower portion 302 is placed into a microwave oven to
heat the liquid. After the liquid is heated, the lower portion 302
is removed from the microwave oven and the upper portion 304 is
attached thereto, thereby sealing the device 300 and completely
containing the heated liquid in the chamber 330. Heat from the
liquid is transferred to the mouthpiece 308 through the connector
306.
Examples of Performance
[0050] The electrically heated/controlled version of the present
invention was used by the inventors on eighteen subjects with
results ranging in shade change from three to ten. The shade levels
and the shade change are based upon measurements taken from the
VITAPAN classical guide, produced by Vident of Brea, California.
The gel contained 20% carbamide peroxide, treatment times varied
from 35-60 minutes, and the age of the subjects ranged from 24-68
years. The results of this study are shown in Table 1.
1TABLE 1 Effectiveness Data. Treatment Time Shade Shade Shade
Subject Age (minutes) Before After Change 1 68 60 B4 B2 10 2 37 50
B3 A1 9 3 64 50 B4 D4 5 4 37 45 A2 <B1 3 5 36 40 A2 B1 3 6 40 35
A3 B2 6 7 39 60 D3 B2 7 8 65 40 A35 C1 6 9 58 60 B4 D4 5 10 47 55
A3 C2 5 11 42 40 A3 A2 5 12 49 40 C1 B2 3 13 28 40 A35 B2/A1 9-10
14 42 50 B3 C1 5 15 43 50 D4 B2 5 16 49 60 A35 B2 9 17 55 60 C4 A35
4 18 35 40 C4 A3 7
[0051] In addition to the tests conducted by the inventors, a
similar study was funded by the inventors and conducted by the
University of Buffalo School of Dental Medicine. The results of
this study involved twenty subjects. Ten were treated with the
present invention and a 3% hydrogen peroxide gel; ten were treated
solely with the same gel. These results confirmed the effectiveness
of the present invention in that under exactly the same conditions
in two 30-minute treatments, the present invention produced whiter
teeth by 4-5 shades higher than the gel alone. The lower
concentration gel (3% hydrogen peroxide) produced up to seven shade
changes as compared to ten shade changes with the 20% carbamide
peroxide gel.
[0052] Trials by the inventors involving the embodiment shown in
FIG. 4 yielded similar results. The major difference between the
two embodiments being that the heat sink needs to be reheated by
boiling water 2-3 times for 20-30 minute treatments in order to
achieve equivalent results. In fact, in one case, the take-home
unit using 20% carbamide peroxide gel and two 40-minute treatments
resulted in a total of 11 shades improvement.
[0053] It will be understood that the embodiments described herein
are merely exemplary and that a person skilled in the art may make
many variations and modifications without departing from the spirit
and scope of the present invention. All such variations and
modifications are intended to be included within the scope of the
invention as defined in the appended claims.
* * * * *