U.S. patent application number 11/197868 was filed with the patent office on 2006-05-25 for apparatus for simultaneous illumination of teeth.
Invention is credited to Anthony J. Cipolla, John E. Prey, John W. Warner, Michael A. Williams.
Application Number | 20060110700 11/197868 |
Document ID | / |
Family ID | 26855091 |
Filed Date | 2006-05-25 |
United States Patent
Application |
20060110700 |
Kind Code |
A1 |
Cipolla; Anthony J. ; et
al. |
May 25, 2006 |
Apparatus for simultaneous illumination of teeth
Abstract
An arrangement, for use in whitening a patient's teeth includes
an arched surface and an array of light-generating devices, for
example, light emitting diodes positioned on the arched surface.
The light-generating devices are arranged to form a relatively
uniform field of light in a particular range of wavelengths, and
further arranged to focus the generated light in an overlapping
manner onto a patient's teeth when the mouthpiece is properly
positioned relative to the patient's face. The proper positioning
is aided by a number of light sources, in the visible range, that
shine on the patient's face in a predetermined manner when the
mouthpiece is properly positioned. To remove whatever heat is
generated at the surface of the patient's teeth in the course of
the procedure, the mouthpiece includes air passages between the
light emitting devices, and a fan that draws air away from the
patient's face.
Inventors: |
Cipolla; Anthony J.; (Trout
Run, PA) ; Warner; John W.; (Warner, NH) ;
Williams; Michael A.; (Midvale, UT) ; Prey; John
E.; (Tower Lakes, IL) |
Correspondence
Address: |
DAVID M QUINLAN, PC
32 NASSAU STREET
SUITE 300
PRINCETON
NJ
08542
US
|
Family ID: |
26855091 |
Appl. No.: |
11/197868 |
Filed: |
August 5, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10958058 |
Oct 4, 2004 |
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11197868 |
Aug 5, 2005 |
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09641646 |
Aug 18, 2000 |
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10958058 |
Oct 4, 2004 |
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09233793 |
Jan 19, 1999 |
6416319 |
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10958058 |
Oct 4, 2004 |
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60158499 |
Oct 8, 1999 |
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60074708 |
Feb 13, 1998 |
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60075222 |
Feb 19, 1998 |
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Current U.S.
Class: |
433/29 ;
433/215 |
Current CPC
Class: |
A61Q 11/00 20130101;
A61K 8/22 20130101; A61C 19/004 20130101; A61C 19/063 20130101;
A61C 19/066 20130101 |
Class at
Publication: |
433/029 ;
433/215 |
International
Class: |
A61C 3/00 20060101
A61C003/00; A61C 5/00 20060101 A61C005/00 |
Claims
1-50. (canceled)
51. A method for whitening a patient's teeth comprising the steps:
(a) applying a dental whitening composition to the teeth; (b)
illuminating the teeth with light from a lamp assembly; and (c)
wherein the lamp assembly is maintained in a constant position
relative to the teeth by a lamp guide comprising a first end and a
second end, wherein the first end of the lamp guide is coupled,
either directly or indirectly, to the patient, and the second end
of the lamp guide is coupled to the lamp assembly.
52. The method of claim 51, further comprising retracting the
patient's lips.
53. The method of claim 51, further comprising retracting the
patient's lips with a lip retractor.
54. The method of claim 51, wherein the dental whitening
composition comprises a two part composition.
55. The method of claim 51, wherein the lamp assembly comprises a
lamp head and a power assembly mounted on a light stand comprising
an adjustable hinge.
56. The method of claim 55, wherein the lamp assembly is a short
arc metal halide lamp.
57. The method of claim 55, wherein the lamp head comprises an IR
filter and a UV filter.
58. The method of claim 55, wherein the lamp head further comprises
a diffuser filter.
59. The method of claim 51, wherein the lamp assembly comprises a
lamp head mounted on a light stand comprising an adjustable
hinge.
60. The method of claim 59, wherein the lamp assembly is a short
arc lamp.
61. The method of claim 59, wherein the lamp assembly is a metal
halide lamp.
62. The method of claim 59, wherein the lamp head comprises an IR
filter and a UV filter.
63. The method of claim 59, wherein the lamp head further comprises
a filter.
64. The method of claim 63, wherein said filter is a diffuser
filter.
65. The method of claim 59, wherein said lamp head further
comprises a lens.
66. A system for tooth bleaching comprising: (a) a bleaching
composition comprising an oxidizing agent; (b) a lamp assembly
comprising a light source, a light output aperture and an
engagement surface; (c) a gap regulating device; and (d) wherein
the bleaching composition is configured to be applied on a tooth
surface of a patient and the gap regulating device is configured to
couple to the patient and to the engagement surface of the lamp
assembly to set a distance between the light output aperture and
the tooth surface to be bleached.
67. The system of claim 66, wherein the bleaching composition
comprises a bleaching gel and an activator.
68. The system of claim 66, wherein the oxidizing agent is hydrogen
peroxide.
69. The system of claim 67, wherein the bleaching gel and the
activator are separately stored.
70. The system of claim 66, wherein the light source is a lamp
comprising mercury gas.
71. The system of claim 66, wherein the gap regulating device
comprises a rod.
72. The system of claim 66, further comprising a lip retractor for
retracting a patient's lips prior to application of the bleaching
composition.
73. The system of claim 66, further comprising a device for
retracting a patient's lips prior to application of the bleaching
composition.
74. The system of claim 66, wherein the engagement surface on the
lamp assembly comprises a bore.
75. The system of claim 66, wherein the gap regulating device
comprises a rod and a bite pad.
76. A system for tooth bleaching comprising: (a) a tooth bleaching
composition comprising an oxidizing agent; (b) a lamp assembly
comprising a lamp head and a power supply mounted on a lamp base
comprising an adjustable hinge; (c) a spacer for setting a space
between the lamp head and a patient's teeth; and (d) wherein the
tooth bleaching composition is configured to be applied to a tooth
surface to be bleached, the lamp assembly is configured to activate
the oxidizing agent from the tooth bleaching composition; and the
spacer is configured to set a gap between the lamp head and the
patient's teeth by coupling to both the patient and the lamp
head.
77. The system of claim 76, wherein the tooth bleaching composition
comprises a two part composition separately stored.
78. The system of claim 77, wherein the two part composition
comprises a bleaching gel comprising hydrogen peroxide and an
activator.
79. The system of claim 76, further comprising cotton rolls or
gauzes for isolating the tooth surface to be bleached.
80. The system of claim 79, further comprising a lip retractor.
81. The system of claim 76, wherein the lamp assembly is a short
arc metal halide lamp.
82. The system of claim 81, wherein the lamp head comprises a UV
filter and an IR filter.
83. The system of claim 76, wherein the spacer is coupled to the
lamp head by engaging a boss located on the lamp head.
84. The system of claim 76, wherein the spacer is coupled to the
patient when the patient bites down on a pad located on an end of
the spacer.
85. The system of claim 82, wherein the lamp head further comprises
a diffuser filter.
86. A system for tooth bleaching comprising: (a) a tooth bleaching
composition comprising an oxidizing agent; (b) a lamp assembly
comprising a lamp head and a power supply mounted on a lamp
comprising an adjustable hinge; (c) a spacer for setting a space
between the lamp head and a patient's teeth; and (d) wherein the
tooth bleaching composition is configured to be applied to a tooth
surface to be bleached, the lamp assembly is configured to activate
the oxidizing agent from the tooth bleaching composition; and the
spacer is configured to set a gap between the lamp head and the
patient's teeth by coupling to both the patient and the lamp head;
and (e) wherein the light is activated for a 20 minute cycle and
wherein the cycle is repeated two additional times with new
bleaching composition applied each time.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 10/958,058, filed Oct. 4, 2004, which is a
division of U.S. patent application Ser. No. 09/641,646, filed Aug.
18, 2000, which claims benefit of U.S. provisional application No.
60/158,499 filed Oct. 8, 1999, and which is a continuation-in-part
of U.S. patent application Ser. No. 09/233,793, filed Jan. 19,
1999, now U.S. Pat. No. 6,416,319, which claims benefit of U.S.
provisional application No. 60/074,708, filed Feb. 13, 1998, and
U.S. provisional application No. 60/075,222, filed Feb. 19, 1998.
All of the foregoing applications are hereby incorporated by
reference to the fullest extent permitted by law.
FIELD OF THE INVENTION
[0002] The present invention relates to the field of cosmetically
improving and altering the appearance of teeth, and more
particularly, to apparatus that is employed in light-activated
bleaching of teeth.
BACKGROUND OF THE INVENTION
[0003] White teeth have long been considered cosmetically
desirable. Unfortunately, due to the presence of chromogenic
(color-causing) substances in food, beverages, tobacco, and
salivary fluid, in addition to internal sources such as blood,
amalgam restoratives, and antibiotics such as tetracycline, teeth
become almost invariably discolored in the absence of intervention.
The tooth structures that are generally responsible for presenting
a stained appearance are enamel, dentin, and the acquired pellicle.
Tooth enamel is predominantly formed from inorganic material,
mostly in the form of hydroxyapatite crystals, and further contains
approximately 5% organic material primarily in the form of
collagen. In contrast, dentin is composed of about 20% protein
including collagen, the balance consisting of inorganic material,
predominantly hydroxyapatite crystals, similar to that found in
enamel. The acquired pellicle is a proteinaceous layer on the
surface of tooth enamel which reforms rapidly after an intensive
tooth cleaning.
[0004] A tooth stain classification system, termed the N (Nathoo)
Classification System, has been proposed (J. of the Amer. Dental
Asso., Vol. 128, Special Supplement, April 1997). One form of
direct dental stain is the N1 type stain which occurs when a
chromogenic material binds to the tooth surface to cause
discoloration similar in color to that of the unbound chromogen.
Another type of direct dental stain is the N2 type stain, in which
a chromogenic material binds to the toothsurface and subsequently
undergoes a color change after binding to the tooth. Finally, an N3
stain is an indirect dental stain, caused by the binding of a
colorless material (prechromogen) to the tooth, said prechromogen
undergoing a chemical reaction that converts it into a chromogen
that causes tooth stain. Tooth stains may be either extrinsic or
intrinsic, depending upon their location within the tooth
structure. For example, extrinsic staining of the acquired pellicle
arises as a result of compounds such as tannins and other
polyphenolic compounds which become trapped in and tightly bound to
the proteinaceous layer on the surface of the teeth. This type of
staining can usually be removed by mechanical methods of tooth
cleaning that remove all or part of the acquired pellicle together
with the associated stain. In contrast, intrinsic staining occurs
when chromogens or prechromogens penetrate the enamel and dentin
and become tightly bound to the tooth structure. Intrinsic staining
may also arise from systemic sources of chromogens or
prechromogens, for instance, when excess fluoride intake during
enamel development leads to the mottled yellow or brown spots
typical of fluorosis staining. Intrinsic staining is not amenable
to mechanical methods of tooth cleaning and generally requires the
use of chemicals, such as hydrogen peroxide, that can penetrate
into the tooth structure, in order to affect a change in the light
absorptivity of the chromogen. Intrinsic tooth staining is
generally more intractable and difficult to remove than extrinsic
tooth staining.
[0005] Consequently, tooth-bleaching compositions generally fall
into two categories: (1) gels, pastes, or liquids, including
toothpastes that are mechanically agitated at the stained tooth
surface in order to affect tooth stain removal through abrasive
erosion of stained acquired pellicle, and (2) gels, pastes, or
liquids that accomplish the tooth-bleaching effect by a chemical
process while in contact with the stained tooth surface for a
specified period, after which the formulation is removed. In some
cases, an auxiliary chemical process or additive, which may be
oxidative or enzymatic, supplements the mechanical process.
[0006] Among the chemical strategies available for removing or
destroying tooth stains, the most effective compositions contain an
oxidizing agent, such as hydrogen peroxide, in order to attack the
chromogen molecules in such a way as to render them colorless,
water-soluble, or both. In one of the most popular approaches to
whitening a patient's teeth, a dental professional will construct a
custom-made tooth-bleaching tray for the patient from an impression
made of the patient's dentition and prescribe the use of an
oxidizing gel to be dispensed into the tooth-b leaching tray and
worn intermittently over a period of time ranging from about 2
weeks to about 6 months, depending upon the severity of tooth
staining. These oxidizing compositions, usually packaged in small
plastic syringes, are dispensed directly by the patient, into the
custom-made tooth-bleaching tray, held in place in the mouth for
contact times of greater than about 60 minutes, and sometimes as
long as 8 to 12 hours. The slow rate of bleaching is in large part
the consequence of the very nature of formulations that are
developed to maintain stability of the oxidizing composition. The
most commonly used oxidative compositions contain the hydrogen
peroxide precursor carbamide peroxide which is mixed with an
anhydrous or low-water content, hygroscopic viscous carrier
containing glycerin and/or propylene glycol and/or polyethylene
glycol. When contacted by water, carbamide peroxide dissociates
into urea and hydrogen peroxide. Associated with the slow rate of
bleaching in the hygroscopic carrier, the currently available
tooth-bleaching compositions cause tooth sensitization in over 50%
of patients. Tooth sensitivity is believed to result from the
movement of fluid through the dentinal tubules, which is sensed by
nerve endings in the tooth. The carriers for the carbamide peroxide
enhance this movement. In fact, it has been determined that
glycerin, propylene glycol and polyethylene glycol can each give
rise to varying amounts of tooth sensitivity following exposure of
the teeth to heat, cold, overly sweet substances, and other
causative agents.
[0007] Prolonged exposure of teeth to bleaching compositions, as
practiced at present, has a number of adverse effects in addition
to that of tooth sensitivity. These include: solubilization of
calcium from the enamel layer at a pH less than 5.5 with associated
demineralization; penetration of the intact enamel and dentin by
the bleaching agents, so as to reach the pulp chamber of a vital
tooth thereby risking damage to pulpal tissue; and dilution of the
bleaching compositions with saliva resulting in leaching from the
dental tray and subsequent ingestion.
[0008] Alternatively, there are oxidizing compositions (generally
those with relatively high concentrations of oxidizers) which are
applied directly to the tooth surface of a patient in a dental
office setting under the supervision of a dentist or dental
hygienist. Theoretically, such tooth whitening strategies have the
advantage of yielding faster results and better overall patient
satisfaction; however, due to the high concentration of oxidizing
agents contained in these so called "in-office" compositions, they
can be hazardous to the patient and practitioner alike if not
handled with care. The patient's soft tissues (the gingiva, lips,
and other mucosal surfaces) must first be isolated from potential
exposure to the active oxidizing agent by the use of a perforated
rubber sheet (known as a rubber dam), through which only the teeth
protrude. Alternatively, the soft tissue may be isolated from the
oxidizers to be used in the whitening process by covering said soft
tissue with a polymerizable composition that is shaped to conform
to the gingival contours and subsequently cured by exposure to a
high intensity light source. Once the soft tissue has been isolated
and protected, the practitioner may apply the oxidizing agent
directly onto the stained tooth surfaces for a specified period of
time or until a sufficient change in tooth color has occurred.
Typical results obtained through the use of a in-office tooth
whitener, with or without activation by heat, range from about 2 to
3 shades (as measured with the VITA.RTM. Shade Guide, VITA.RTM.
Zahnfarbik, Bad Sackingen, Germany).
[0009] The range of tooth shades in the VITA.RTM. Shade Guide
varies from very light (B1) to very dark (C4). A total of 16 tooth
shades constitute the entire range of colors between these two
endpoints on a scale of brightness. Patient satisfaction with a
tooth whitening procedure increases with the number of tooth shade
changes achieved. Typically, the minimum generally accepted change
is about 4 to 5 VITA.RTM. shades.
[0010] Attempts have been made to activate peroxides with heat
and/or light for the purpose of whitening teeth. U.S. Pat. No.
4,661,070 discloses a method of whitening stained teeth which
includes the application of a concentrated solution of hydrogen
peroxide within the pulp chamber or upon the surface of a
discolored tooth, followed by exposing the discolored tooth to
optical energy consisting of both ultraviolet and infrared light.
The preferred wavelengths of light disclosed by this patent are
from 320 to 420 nanometers and from 700 to 1200 nanometers, with
light in the visible spectrum (wavelengths from 500 and 700
nanometers) being suppressed. The disclosed method suffers from two
serious drawbacks: (1) ultraviolet light can be hazardous to the
patient and practitioner alike and (2) infrared light may cause
irreversible pulpitis if not handled with care.
[0011] These drawbacks are partially addressed in U.S. Pat. No.
4,952,143 which discloses a dental bleaching instrument which
filters out ultraviolet light and has a temperature regulation
mechanism. This patent also discloses the use of visible light with
wavelengths ranging from 450 to 500 and 650 to 750 nanometers to
produce a dark reddish/purple beam which facilitates the aiming and
focusing of the instrument.
[0012] U.S. Pat. No. 5,032,178 discloses compositions and methods
to improved tooth whitening efficacy which uses exposure to
"optical energy", preferably in the visible spectrum wavelength
range of 400 to 700 nanometers. The compositions disclosed in this
patent require the use of (1) an inert silica gelling agent, (2) a
catalytic accelerator (either manganese sulfate monohydrate or
ferrous sulfate), (3) an agent for providing thixoplasticity and
thickening properties to the composition, such as cellulose ethers
and methyl vinyl ethers, and (4) a means for indicating completion
of the bleaching treatment of the teeth, comprising a redox color
indicator for transforming from one color to another in response to
the dissociation of hydrogen peroxide over a given time period.
Compositions described therein are mixed homogeneously prior to use
and all of the required components, including the catalyst, are
dispersed evenly throughout the mixture. The compositions described
are not highly transparent to light energy in the range of 400 to
700 nm, due to the presence of the high levels of inorganic silica
particles. Commercial mixtures based on this patent (available
under the trade name Shofu Hi-Lite.RTM. from Shofu Dental
Corporation, Menlo Park, Calif.) confirm that these preparations
are not transparent to visible light, but rather are quite opaque.
Typical results obtained using such compositions and methods are
about 2 to 3 VITA.RTM. shades improvement in tooth color, similar
to that achieved with compositions that do not employ light energy
in the process of bleaching teeth.
[0013] U.S. Pat. No. 5,240,415 discloses a dental bleaching system
comprising a multi-component kit, one of the required components of
said kit being fumed silica. As described above, silica renders an
aqueous composition relatively opaque to visible light energy.
Again, a tooth shade improvement of about 2 to 3 VITA.RTM. shades
can be expected through the use of this type of composition.
[0014] A commercial product called Opalescence Xtra available for
bleaching teeth in the controlled environment of a dental office
has recently been introduced by Ultradent Products, Inc, South
Jordan, Utah. This product is believed to be based on the
disclosure of U.S. Pat. No. 5,785,527. The commercial product is
supplied in a plastic syringe and is described in the accompanying
literature as a light-activated tooth whitening gel, which contains
approximately 35% hydrogen peroxide. A pH determination showed the
product to have a neat pH at 25.degree. C. of about 4.0. The
product is thickened to a loose, gel-like consistency with a
polymer. Additionally, the product as sold, and as disclosed in
U.S. Pat. No. 5,785,527, contains a bright orange pigment or dye
(carotene), which presumably serves as the "photosensitizer". The
manufacturer also claims that the photosensitizer is able to absorb
light energy and convert it into heat energy, thereby increasing
the activity of the peroxide as a tooth bleaching agent. The
presence of a photoabsorber in the aforementioned composition
renders it relatively opaque to wavelengths from about 400 to 700
nm. Exposure of this composition to light energy between 400 and
700 nm results in a gradual fading of the orange color, presumably
due to a photobleaching effect in the presence of the hydrogen
peroxide. Comparative clinical results show an improvement in tooth
color of from about 3 to 4 VITA.RTM. shades, which is highly
dependent upon the contact time of the composition on the tooth
surface, rather than any particular light or heat activation
regimen. In addition, the low pH of the commercial product may
cause a reduction in the microhardness of tooth enamel, due to the
dissolution of hydroxyapatite crystals (which can occur at a pH of
around 5.5 or less).
[0015] Devices for use in light/heat-activated tooth whitening
procedures include the commercially available Union Broach
Illuminator System, from Union Broach, a Health\Chem Company, New
York, N.Y. This device, as described by the manufacturer, provides
direct, full spectrum illumination to all of the teeth found in the
front of the average adult's mouth. However, this device does not
uniformly illuminate all sixteen central teeth in the front upper
and lower arches because of the curvature of the dentition. This
potentially gives rise to uneven results. In addition, the Union
Broach device generates a great deal of heat which is both
uncomfortable for the patient and potentially damaging to the
teeth.
[0016] There is thus a need for improved compositions, methods and
devices for whitening teeth that overcome the limitations of the
prior art described above. In particular, there is a need for tooth
whitening compositions and methods capable of whitening teeth
quickly and safely, without harm to tooth enamel, dentin, or pulp.
The compositions and methods of the present invention described
herein satisfy these and other needs.
[0017] It is an object of this invention to provide fast and safe
tooth whitening compositions and methods that can be activated or
accelerated by the use of light energy.
[0018] It is a further object of this invention to provide a tooth
whitening composition that shortens the treatment time required to
obtain a given level of tooth whitening that is satisfactory to
both the patient and the dentist.
[0019] It is another object of the present invention to provide
tooth whitening compositions that are relatively transparent to
light energy in the wavelength range at which tooth chromogens
absorb in order to allow exposure of the tooth enamel surface to
said light energy while in contact with said tooth whitening
compositions.
SUMMARY OF THE INVENTION
[0020] The present invention encompasses methods for whitening
teeth, wherein a stained tooth surface is contacted with (i) a
tooth whitening composition that is transparent to photoactive
light and (ii) a photosensitive agent that is responsive to the
wavelengths of light that are transmitted through the whitening
composition and, after contacting with the composition and agent,
the tooth is exposed to a biologically safe and effective level of
photoactinic light in order to enhance the ability of the oxidizing
compound in the whitening composition to effect rapid tooth
whitening.
[0021] Also disclosed and contemplated within the scope of this
invention are methods for whitening teeth, wherein a stained tooth
surface is contacted with an oxidizing compound that is transparent
to the wavelengths of light that are absorbed by tooth stain
chromogens, and then exposing the treated tooth to a biologically
safe and effective level of those same wavelengths of light in
order to effect rapid tooth whitening.
[0022] Also disclosed and contemplated within the scope of this
invention are the compositions and compounds described above and
devices for whitening teeth, wherein a minimum of eight central
teeth in both the upper and lower arches in an adult are
simultaneously and uniformly illuminated with a biologically safe
and effective level of actinic light to effect rapid tooth
whitening.
[0023] An improvement in the art is achieved with an arrangement
where a tooth whitening composition is applied to a patient's teeth
and where a mouthpiece that is placed in a position outside of a
patient' mouth includes means for generating a light that is
adapted to be simultaneously applied to all of the patient's teeth
and to, thereby, accelerate the tooth whitening process.
[0024] In one embodiment, a mouthpiece having an arched surface not
unlike the arched surface of prior art mouthpieces includes an
array of light-generating devices, for example, light emitting
diodes. The light-generating devices are arranged to form a
relatively uniform field of light in a particular range of
wavelengths, and further arranged to generally concentrate the
generated light onto a patient's teeth when the mouthpiece is
properly positioned relative to the patient's occlusal plane. In
one embodiment, the proper positioning is aided by a number of
light sources, in the visible range, that shine on the patient's
face in a predetermined manner when the mouthpiece is properly
positioned. In another embodiment, the mouthpiece is aligned with a
positioning device that is held between the patient's teeth (i.e.,
in the occlusal plane). To remove whatever heat is generated in the
mouthpiece unit in the course of the procedure, the mouthpiece
includes air passages, and a fan that draws air through the
mouthpiece and away from the patient's face.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1: A diagram of a device for illuminating the eight
central teeth in both the upper and lower arches of an adult for
use in a light-activated tooth whitening procedure.
[0026] FIG. 2: A diagram illustrating the position of two devices
for illuminating the eight central teeth in both the upper and
lower arches of an adult for use in a light-activated tooth
whitening procedure.
[0027] FIG. 3: Graph of Comparative Spectra
[0028] FIG. 4: Spectral Curves of Light Attenuation
[0029] FIG. 5: Shows a portable tooth whitening device
[0030] FIG. 6 presents an exploded perspective view of an
illustrative embodiment of a tooth whitening assembly in
conformance with the principles of this invention,
[0031] FIG. 7 is a back view of the illustrative embodiment;
[0032] FIG. 8 shows a surface on which light-generating devices are
positioned that is curved in three dimensions.
[0033] FIG. 9 presents an illustrative end-piece of an arm
arrangement to which the FIG. 6 assembly may attach;
[0034] FIG. 10 illustrates the light profile of a light-generating
device, as well as the profile that may result from focusing of the
light;
[0035] FIG. 11 shows surface 15, a plurality of light profile lobes
that emanate from light sources at surface 15, where the lobes are
directed to overlap and where, consequently, the beams add on a
power basis to form a combined field of light;
[0036] FIG. 12 depicts an arrangement with a single row of
light-generating devices;
[0037] FIG. 13 depicts an arrangement that employs only two rows of
light-generating devices in the FIG. 6 assembly;
[0038] FIG. 14 depicts an arrangement that employs angling pedestal
upon which the light-generating devices are placed, thus causing
the light lobes from the different devices to be angled toward each
other and to thereby to overlap;
[0039] FIG. 15 depicts an arrangement that employs the curvature of
surface 15 to cause light lobes to overlap;
[0040] FIG. 16 shows a linear array of LEDs used in the FIG. 1
assembly;
[0041] FIG. 17 shown a staggered array of LEDs that may be used in
the FIG. 1 assembly;
[0042] FIG. 18 illustrates an electrical connection of the LEDs on
the back (convex) surface of member 10;
[0043] FIG. 19 shows an arrangement for sliding strips that contain
LEDs into member 10 of the FIG. 1 assembly, and
[0044] FIG. 20 shows a different arrangement for sliding
mini-circuit boards with edge-mounted LEDs into member 10 of the
FIG. 6 mouthpiece.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0045] This section details the preferred embodiments of the
subject invention. These embodiments are set forth to illustrate
the invention, but are not to be construed as limiting. Since the
present disclosure is directed to those skilled in the art field
and is not primer on the manufacture of tooth whitening
compositions or their use or on devices for using such
compositions, basic concepts and standard features known to those
skilled in the art are not set forth in detail. Details for
concepts such as choosing appropriate construction materials or
ingredients, operating conditions or manufacturing techniques, etc.
are known or readily determinable to those skilled in the art.
Attention is directed to the appropriate texts and references known
to those skilled in the art for details regarding these and other
concepts which may be required in the practice of the invention;
see, for example, Kirk-Othmer Encyclopedia of Chemical Technology,
4th Edition, Volumes 4 (1992), 13 (1995), 18 (1996), John Wiley
& Sons, NY; Goldstein and Garber, Complete Dental Bleaching,
Quintessence Publishing Co. 1995 and the aforementioned Journal of
the American Dental Association, Vol. 128, Special Supplement,
April 1997, the disclosures of which are hereby incorporated by
reference into the present disclosure to aid in the practice of the
invention. The development of the inventive compositions and
methods described herein resulted from the unexpected discovery
that extremely rapid tooth whitening occurs by allowing actinic
radiation to penetrate through the oxidizing compound, which is
placed directly onto the tooth surface to be whitened. This
discovery is antithetical to all prior art compositions that
include a light (or heat) absorbing additive dispersed directly in
and homogeneously throughout the oxidizing compound. The inventive
compositions, on the other hand, allow actinic radiation to reach
the stained tooth surface at higher power densities than prior art
compositions that are specifically designed to absorb light.
Actinic radiation is thus more effectively utilized compared to
prior art compositions and methods in which compositions are both
opaque to most wavelengths of light and are activated directly by
the actinic radiation. As the greatest oxidizing activity is
required in the few millimeters of enamel and dentin at the tooth
surface, the present inventive compositions and methods are more
effective at removing tooth stains, in many cases with lower levels
of active oxidizing agents, thereby resulting in safer compositions
for use in the oral cavity.
[0046] For the purpose of this disclosure, the term actinic
radiation shall mean light energy capable of being absorbed by
either an exogenous photosensitizing agent or an indigenous tooth
chromogen. Also for the purpose of this disclosure,
photosensitizing actinic radiation will mean light absorbed by a
specific photosensitive agent, where as chromosensitizing actinic
radiation will mean light absorbed by one or more tooth chromogens.
The terms "actinic radiation" and "actinic light" will be referred
to interchangeably.
[0047] Also for the purposes of this disclosure, the term
"transparent" shall mean having greater than 70% transmission of
light at a specified wavelength or within a wavelength range. In
addition, all composition ingredient percentages are by weight
unless otherwise stated.
[0048] Various modes of application of the inventive tooth
bleaching compositions are effective, although methods that allow
for the accumulation or concentration of the photosensitizer within
the acquired pellicle, enamel, and dentin (the three tooth
structure primarily associated with the majority of tooth staining)
are most preferred. This is best accomplished by contacting the
stained tooth surface with the photosensitizer prior to contacting
the same stained tooth surface with the oxidizing composition. In
this way, the photosensitizer is able to penetrate into the tooth
structure, thus being present at the site of the tooth chromogen(s)
prior to contact with the oxidizing composition and prior to
exposure to the actinic radiation source.
[0049] Photosensitizing agents useful in accomplishing the desired
tooth whitening effect include any compounds capable of absorbing
light energy at biologically acceptable wavelengths prescribed by
the limits of safety for use in the oral cavity. In general, such
wavelengths are from about 350 nanometers (nm) to about 700 nm,
encompassing a portion of the UVA spectrum (300 to 400 nm) and most
of the visible light spectrum (400 to 700 nm). Examples of
compounds which may convert light energy to either heat of chemical
energy, include semiconductor particles (particularly
nanometer-scale titanium dioxide and zinc oxide), benzophenone
derivatives, benzotriazole derivatives, diketones (such as
camphorquinone and benzil), metal-ligand complexes (such as ferric
potassium oxalate, manganese gluconate, and various
metal-bisphosphonate chelates), phthalocyanin-metal complexes, and
others. A specific example of a suitable photosensitizing
composition is an aqueous dispersion of zinc oxide with particle
sizes between 5 and 20 nanometers. Any molecule capable of
absorbing a photon of light in the wavelength range of from about
350 nm to about 700 nm and subsequently converting the energy in
said photon of light into the useful energy of oxidation either
alone or in the presence of an auxilliary oxidizing agent, is
contemplated to have utility in the practice of the present
invention.
[0050] It is preferred that the inventive photosensitizers are of a
molecular size, charge, pH and hydrophobicity/hydrophilicity to
allow for effective penetration into the deeper structures of
enamel and dentin. The more readily a photosensitizer penetrates
the tooth structure, the more likely that, upon exposure of the
photosensitizer to actinic radiation at the appropriate wavelength
and energy, said energy will be converted into oxidative activity
at the site of, or in close proximity to, the chromogen itself.
Photosensitizers having a molecular size, net charge, pH, and/or a
hydrophobicity/hydrophilicity which prevent or limit penetration
into deeper tooth structures are of utility in the practice of the
present invention, but may be limited to the removal and/or
destruction of chromogens located at the outer tooth surface
(extrinsic stains).
[0051] Especially preferred photosensitizers belong to the general
class of water-soluble metal-ligand complexes which absorb light in
the range of from about 350 nm to about 700 nm. For the purposes of
the present disclosure, the term "ligand" will mean an organic
molecule capable of complexing or associating with a metal ion in
aqueous solution, such that the reactivity, solubility, or any
other physical property of said metal ion is changed. Such
metal-ligand complexes are also known as metal-coordination
complexes. Suitable metals ions include iron, manganese, copper,
and other transition metal ions. Various valence states may be used
or may be present simultaneously. The metal ions may be present in
saliva, plaque, or the acquired pellicle on the tooth surface.
Metal ions may also contribute, through formation of oxides, to
certain types of tooth stains. Suitable metal ion ligands include
chelating agents capable of associating with the metal ions above
in aqueous solution, resulting in a water-soluble metal-chelate
complex that absorbs light between about 350 and 700 nm.
Illustrative, but by no means limiting, examples of
metal-coordination complexes are formed from the association of
iron, manganese and copper with chelators such as ethylenediamine
tetraacetic acid (EDTA), diethylenetriamine pentaacetic acid
(DETPA), nitrilotriacetic acid (NTA),
1-hydroxyethylidene-1,1-diphosphonic acid, ethylenediamine
tetra(methylenephosphonic acid), diethylenetriamine
penta(methylenephosphonic acid), and polyols such as sorbitol,
xylitol, mannitol, maltitol, lactitol and other non-carboxylated
polyhydroxy compounds more fully described in EP 443,651, such
description being incorporated herein by reference. Any organic
multidentate chelating agent capable of forming a photoabsorbing
coordination complex with a metal ion can be presumed to have
utility in the present inventive compositions for and methods of
whitening stained teeth.
[0052] A number of the inventive metal-ligand complexes have an
absorption spectrum that is pH-dependent; in general, such
complexes will display a greater degree of absorption between 350
and 700 nm at a pH of greater than about 4.0, light absorption in
this range increasing with increasing pH. For instance, the aqueous
complex formed between 1-hydroxyethylidene-1,1-diphosphonic acid
and ferrous ions is virtually transparent to visible light at pH
3.0, but absorbs strongly in the spectral region between 350 and
500 nm as the pH is raised to 7.0.
[0053] In some cases, a photosensitizer precursor may be included
directly within the oxidizing composition, where it does not
readily absorb light in the visible region of the spectrum from 400
to 700 nm. However, upon contact with the tooth surface (when
placed there with the oxidizing composition), the photosensitizer
precursor may combine, for instance, with a metal ion such as iron
present in saliva or found in the interstitial fluid of enamel and
dentin, resulting in the formation, in situ, of an active
photosensitizer capable of activating the oxidizing compound upon
exposure to actinic radiation. Obviously, only those compounds that
are stable in a highly oxidative environment are suitable for
inclusion directly in the oxidizing composition. An example of such
a compound is 1-hydroxyethylidene-1,1-diphosphonic acid (available
commercially under the trade name Dequest 2010 and sold as a 60%
active solution by Monsanto Corporation, St. Louis, Mo.).
[0054] The ability of certain metal chelates to act as
photosensitizers has been noted in the literature by various
workers. For example, Van der Zee, et al ("Hydroxyl Radical
Generation by a Light-Dependent Fenton Reaction" in Free Radical
Biology & Medicine, Vol. 14, pp 105-113, 1993) described the
light-mediated conversion of Fe (III) to Fe (II) in the presence of
a chelating agent and hydrogen peroxide. The reduction of Fe (III)
chelates by light at 300 nanometers to yield Fe (II) was shown to
proceed steadily over a period of about 30 minutes, with
conversions to Fe (II) ranging from about 40% to about 80%,
depending upon the particular chelating compound studied. The Fe
(II) thus created initiated a Fenton-type degradation of the
hydrogen peroxide, yielding hydroxyl radicals that were
spin-trapped and detected by electron spin resonance (ESR). It was
not suggested or implied by the authors that this photochemical
reaction would have utility in the oxidation of chromophores, such
as those found in a human tooth.
[0055] Useful oxidizing compounds include liquids and gels,
preferably containing a peroxide or peroxyacid known in the art.
Such oxidizing compounds include, but are not limited to, hydrogen
peroxide, carbamide peroxide, alkali metal peroxides, alkali metal
percarbonates, and alkali metal perborates. Often, it may be
desirable to utilize a peroxyacid compound, such as peroxyacetic
acid (for instance, when attempting to eliminate highly intractable
tooth stains caused by tetracycline) in the tooth whitening
composition. The peroxyacid may be included directly within the
oxidizing composition (providing that transparency to light energy
between about 350 and about 700 nanometers is maintained).
Alternatively, the peroxyacid may be formed by combining two or
more separate phases (one of which contains a peroxyacid precursor,
such as glyceryl triacetate and a second that contains one of the
oxidizing compounds listed above) prior to application to the tooth
surface. Preferably, the peroxyacid is formed in situ, by
contacting the tooth surface with a peroxyacid precursor prior to
the application of an oxidizing compound, the peroxyacid is thus
formed only on and within the stained tooth structure, where it is
most beneficial to the tooth whitening process. Suitable peroxyacid
precursors include, but are not limited to, glyceryl triacetate,
acetylated amino acids, acetylsalicylic acid, and
N,N,N',N'-tetraacetyl ethylenediamine, vinyl acetate polymers and
copolymers, acetylcholine, and other biologically acceptable
acetylated compounds.
[0056] The oxidizing compounds are liquid, gel, or solid
compositions transparent to the wavelength(s) of light capable of
activating the photosensitizing agent at the tooth surface light
energy otherwise will be attenuated by the film or layer of
oxidizing compound between the actinic radiation source and the
photosensitizer at the tooth enamel surface. As the tooth enamel
surface is the location of the tooth discoloration, the most
effective method of whitening teeth will occur when most or all of
the light energy reaches the photosensitizer at the tooth enamel
surface. An example of a suitable composition that is transparent
to light energy between 380 and 500 nm is a 6% hydrogen peroxide
gel with a pH of about 7.0 that has been thickened to approximately
100,000 cps with neutralized carboxypolymethylene.
[0057] Another unexpected benefit of utilizing an oxidizing
composition transparent to photosensitizing actinic radiation is
that certain wavelengths of light seem to be absorbed by tooth
chromogens in a manner that promotes their oxidation to a
non-chromogenic state. Reflectance studies show that dentin and
enamel transmit green light, reflect yellow/red light and absorb
blue light. Although not wishing to be bound by any particular
theory, light is absorbed by the molecules responsible for tooth
discoloration; thus, tooth chromogens may act in a manner similar
to that of photosensitizers. In particular, exposure to certain
wavelengths may raise the energy state level of pi electrons
carbonyl (C.dbd.O), double bond (C.dbd.C) and conjugated double
bond (C.dbd.C--C.dbd.C) moieties, making them more susceptible to
attack by active oxidizing species such as perhydroxyl anion
(HOO--), peroxyacid anions (RCOOO--), and radical species such as
hydroxyl radical (HO*) and perhydroxyl radical (HOO*). In order to
destroy or solubilize chromogenic substances, the activation energy
of the reaction between one of the above light-absorbing moieties
and an active oxidizing species must be overcome; thus, light
assisted chromogen attack leads to more efficient destruction of
the molecular moieties responsible for the appearance of tooth
discoloration by raising the energy state of electrons in specific
chemical bonds within a light-absorbing molecule from a normal pi
bonding orbital to a pi antibonding orbital. Whilst in the less
stable pi antibonding orbital, a light absorbing double bond has
considerable single bond character and is much more easily attacked
by oxidizing agents such as peroxides and peroxyacids. In theory,
actinic light of a specific energy and wavelength, simply through
the process described above, may utilize a tooth chromogen molecule
as a photosensitizer in order to improve the efficacy of a given
oxidative composition in contact with said tooth chromogen.
[0058] A light-activated tooth whitening method, in accordance with
a specific embodiment of the invention includes contacting the
tooth enamel surface with the photosensitizing agent, then
contacting the photosensitizer-treated tooth surface with the
oxidizing compound, and, thereafter, exposing the tooth surface to
light energy capable of activating the photosensitizer which, in
turn, activates the oxidizing compounds at the tooth enamel
surface.
[0059] Another light-activated tooth whitening method, in
accordance with another embodiment of the invention includes
contacting the tooth enamel surface with an oxidizing compound
which contains a photosensitizer precursor, whereby said precursor
is seen to absorb actinic radiation in the range of 350 to 700 nm
only after contact with said tooth surface. Once the
photosensitizer precursor becomes light absorbent, the tooth
surface is exposed to light energy capable of activating the now
absorbent photosensitizer, which in turn activates the oxidizing
compound at the tooth surface to whiten the tooth.
[0060] A further light-activated tooth whitening method, in
accordance with another embodiment of the invention includes
contacting the tooth enamel surface with an oxidizing compound and
thereafter exposing said tooth enamel surface to actinic radiation
corresponding to a tooth chromogen molecule absorption wavelength.
The preferred wavelengths of light in this embodiment include those
between about 350 and about 700 nanometers, a more preferred
embodiment include those between about 380 and about 550 nanometers
with the most preferred wavelengths being between about 400 and
about 505 nanometers. As in all of the methods described above, the
oxidizing composition must be transparent to the actinic radiation
utilized in order to allow the wavelength-specific light energy to
reach the tooth surface and underlying structure.
[0061] Yet another light-activated tooth whitening method, in
accordance with another embodiment of the invention includes
contacting the tooth enamel surface with a peroxyacid precursor
prior to contacting said tooth enamel surface with an oxidizing
compound and subsequently exposing to actinic radiation as
described above. The peroxyacid precursor may be placed on the
tooth surface together with or separately from a
photosensitizer.
[0062] Stained teeth may be treated individually, for instance, by
directing the light to a single tooth surface by means of a fiber
optic light guide. In this manner, several stained teeth are
exposed to light in sequence, the dentist or hygienist moving the
light guide from tooth to tooth during the procedure. This process
is both labor intensive and time consuming for the dentist or
hygienist as well as tedious for the patient. Alternatively, all of
the stained teeth may be exposed to light simultaneously either by
direct illumination from a light source shaped substantially like
the dental arch or by indirect illumination from a light guide or
device that is capable of illuminating all of the front teeth at
once.
[0063] One such device for the simultaneous and uniform
illumination of at least eight central teeth in both the upper and
lower arches is illustrated in FIG. 1. This preferred embodiment
has three linear optical outputs 11, 12, and 13 precisely
positioned on three front (patient facing) surfaces 1, 2, and 3. In
a more preferred six bar embodiment, two three bar devices are
stacked one on the other resulting in six optical outputs on the
front patient facing surfaces as illustrated in FIG. 2
[0064] Although FIGS. 1 and 2 illustrate embodiments having 3
outputs and 6 outputs, respectively, it is contemplated that the
device may have any number of outputs or emitters, from one to a
high multiple of outputs, each output consisting of an individual
fiber or fiber bundle that ultimately is connected to a light
source. The embodiments of a device for the simultaneous and
uniform illumination of at least eight central teeth in both the
upper and lower arches were described in U.S. application Ser. No.
09/233,793, which is herein incorporated by reference. A preferred
embodiment of this device has three linear optical outputs
precisely positioned on three front (patient facing) surfaces. A
more preferred embodiment of this device has two three bar devices
stacked on the other resulting in six optical outputs on the front
patient facing surfaces. Other embodiments of this invention
include any number of outputs or emitters, from one to a high
multiple of outputs. Each output can comprise an individual fiber
or fiber bundle that ultimately is connected to a light source.
Embodiments having 3 or 6 outputs are presently preferred for the
device because they achieve fairly uniform illumination of the
eight or more central teeth without excessive manufacturing
problems or costs. More than six outputs, of course are feasible
and may in fact be beneficial in terms of uniformity of
illumination.
[0065] The front surfaces of the device are positioned to give an
output configuration such that the combined beams from each optical
output converge to illuminate at least the eight central teeth in
both the upper and lower arches or the are from the incisors to the
first premolars in each half arch, a total area of about 10.4
cm.sup.2 in the average male. Although depicted in FIG. 1 as linear
in form, these outputs may be of any shape, e.g., circular,
triangular or linear. Linear forms are preferred. The preferred
embodiments have six linear outputs, each output having a length to
width ratio of about 16.+-.20%--i.e., ratios of 12.8 to 19.2. In
the most preferred embodiment, 80% of the light projected from the
outputs onto the 8 upper and lower central teeth is within an area
between about 0.9 and about 1.5 inches wide, the approximate
distance from the top of the enamel of the top teeth to the bottom
of the enamel of the bottom teeth. Each optical output preferably
is connected to a distal light source by two glass or plastic fiber
optic bundles which originate at the distal light source, enter the
device through a socket 20 and terminate at the trifurcated linear
output window. Non-uniformity in fiber transmission is generally
observed to be minor in the absence of actual breaks in the fibers.
Variation in optical output from point to point at the surface of
each output or emitter should be no more than about .+-.10%.
[0066] Whether illumination of the stained teeth is performed
individually or as a whole, the light emerging from a direct or
indirect source may be continuous ("on" the entire procedure),
interrupted continuous (primary "on" with short rest
interruptions), pulsed ("on" and "off" in a predetermined timed
sequence and intensity), or a combination of continuous,
interrupted continuous and pulse. In a preferred embodiment from
about 10 to about 200 milliWatt/cm.sup.2 of light is applied
continuously to the front surface of the teeth for a total period
of time from about 10 to about 90 minutes. In a more preferred
embodiment from about 100 to about 160 milliWatt/cm.sup.2 of light
is applied continuously or continuously with short interruptions to
the front surface of the teeth for a period of time from about 10
minutes to about 30 minutes followed by an interruption or "off"
period of about 1 to 10 minutes, with the cycle repeated for a
total time of approximately 40-60 minutes. In one envisioned
embodiment of the invention a feed-back mechanism based on
reflectance would be used to monitor bleaching efficiency and
regulate the total amount of actinic radiation applied. In all
embodiments of the invention the positioning of the light source
affects the energy density applied to the teeth as power density
decreases with distance. The preferred placement of the light
source will vary depending on the precise nature of the device. For
the device described above, the preferred distance for placement of
the device is from directly in front of the surface of the teeth up
to about 2.0'' in front of the surface of the teeth (when measured
from the middle of the light source to the central tooth), with a
distance of about 1.75'' being most preferred.
[0067] A further development of this device described above is a
portable tooth whitening device which is shown in FIG. 5. This
portable tooth whitening device comprises one or more lamps capable
of treating any number of teeth. In a preferred embodiment, the
portable tooth whitening device can simultaneously treat at least
16 teeth at one time. The portable tooth whitening device further
comprises a fiber optic delivery system, a flexible articulated
arm, and a portable support structure which is on wheels.
Preferably the portable tooth whitening device of the invention has
a control panel. In a more preferred embodiment the portable tooth
whitening device has a key card system for controlling access and
usage. Preferably the key card system is the Bull.RTM.SafePad.RTM.
reader with Smart Card.RTM..
[0068] Preferably the device of the invention has a curing lamp in
a holster. A preferred curing lamp is a Demetron.RTM.. Preferred
curing lamps emit light in about the blue wavelength region.
Preferably the curing light has a light filter to protect the eyes
of the operator of the device from errant light from the curing
lamp.
[0069] A preferred portable support structure has dimensions of
about 24''.times.15'', by 31'' high and an arm assembly which adds
about another 20'' in height in the stowed position.
[0070] The control panel has an on/off button, a calibration
button, and buttons to control the illumination time. The
calibration button calibrates the system to insure that the energy
setting is correct. Preferably the control panel is at an
inclination from the vertical of about 45' so that it can be easily
viewed by the operator.
[0071] The entire portable tooth whitening device is on wheels and
has a flexible arm. It is portable and can be rolled about on the
wheels. The arm has glass or plastic fibers, for transmitting
light, attached to a structural support. This structural support,
as shown in FIG. 5, provides a flexible arm with a wide range of
articulation which enables the system to be used in any dental
setting and with patients in a wide range of positions. For
example, the portable tooth whitening device of the invention can
be used in such dental settings as typical dental offices,
orthodontic offices, spas in cruise ships, and the like. It can
also be moved out of the way for easy storage. The flexibility of
the arm allows for the output to be positioned at any angle
necessary for whitening the teeth of a patient in either a
reclining position or a sitting position, or any angle in between.
For example, the head region of the light (1), as shown in FIG. 5,
can be in a horizontal position for treating a patient in a sitting
position. The head region can be adjusted to an about vertical
disposition for treating a patient in a reclining position. The
head region can also be adjusted to any other angle between the
horizontal and vertical positions. The flexibility of the arm
further enables the portable tooth whitening device to be used on
either the left or right side of the dental chair.
[0072] In a preferred embodiment of the invention, the flexibility
of the arm is conferred by the structural arrangement shown in FIG.
5 which has three knuckles with large ranges of motion. More
specifically, knuckle one (2), which is nearest to the table, has
an almost 360.degree. range of motion about an axis vertical or
approximately vertical to the table. Knuckle two (4), which is
disposed between a first support arm (3) and a second support arm
(5) also has an almost 360.degree. range of motion about an axis
vertical or approximately vertical to the table. Knuckle two (4)
also has a range of motion in the vertical direction of
approximately .+-.45.degree.. Knuckle three (6), which is disposed
between the head region (1) and the second support arm (5) also has
an approximately 360.degree. range of motion about an axis which is
vertical or approximately vertical to the table. Knuckle three (6)
also has a vertical range of motion of approximately
.+-.90.degree..
[0073] A number of different sources of actinic radiation have been
shown to have utility in the practice of the present invention. In
general, any light source capable of emitting actinic radiation in
the wavelength range necessary to activate either the inventive
photosensitizer(s) or otherwise raise the energy state of tooth
chromogens, is contemplated to have utility in the practice of this
invention. In particular, light sources capable of emitting actinic
radiation that is both biologically safe and effective are
preferred, especially those sources which emit limited amounts of
infrared light (700 nm and above). Infrared light more readily
penetrates the tooth structure and may cause an excessive
temperature rise in pulpal tissue.
[0074] It is preferred that light sources (combined with filters)
emitting only those wavelengths necessary for the activation of the
inventive photosensitizer and/or the activation of a tooth stain
chromophores be used in the process of whitening teeth with the
inventive compositions. It is generally accepted that a pulpal
temperature rise of more than 5.5.degree. C. for a significant
period of time can be irreversibly damaging to the tooth
structure.
[0075] More specifically, light sources which emit actinic
radiation in the wavelength range from about 350 nanometers to
about 700 nanometers are especially preferred, in that both the
photosensitizers described herein and the tooth chromogen molecules
responsible for tooth staining absorb primarily in this region of
the spectrum. Light sources which emit actinic radiation in the
wavelength ranges from about 400 and about 505 nanometers are most
preferred. Output uniformity should be about +/-10% over the area
of the beam once transmitted through a glass or plastic fiber to
the optical output which may be placed in front of a patient's
teeth. Although there are no limitations on the input and length
dimensions of such a fiber, one of about 10 millimeters in diameter
and 3 meters (about 10 feet) in length is preferred. Again,
although there are no limitations on the input and length
dimensions of such a fiber, for the portable tooth whitening device
it is preferable to use one of about 10 millimeters in diameter and
about 6.5 feet in length. Such energy may be provided by a source
which generates a continuous electromagnetic spectrum filtered to
the preferred wavelengths with a variation of no more than about
+/-10% or by a source which generates an emission line spectrum, or
a combination of both. Suitable lamps which emit actinic radiation
in the preferred range of wavelengths include linear flash lamps,
tungsten halogen metal halide, Xenon short arc, Mercury short arc,
Mercury Xenon short arc, Argon plasma arc, and Argon short arc
lamps, diode lasers and light emitting diodes (LEDS), among others.
The output of two Mejiro BMH 250 watt metal halide lamps filtered
through dichroic filters to between about 400 and 505 nanometers
meet these criteria.
[0076] Another embodiment of the invention provides a mouthpiece
having a plurality of light generating devices (such as fiber optic
outputs or LED emitters) that can project a relatively uniform
field of light energy onto the labial surfaces of the teeth. The
mouthpiece can have a shape substantially like the dental arch.
However, mouthpieces of all shapes can be made to project a uniform
field of light onto the labial surfaces of the teeth. The term
field of light, as used in this specification, means light
projected onto a surface. The term uniform field of light, as used
in this specification, means that the energy density remains
constant over the surface onto which the light is projected. FIG. 6
presents a perspective view of an illustrative mouthpiece 100,
comporting with the principles of this invention, with the two main
components of this embodiment (elements 10 and 11), being separated
for sake of clarity. FIG. 7 shows a perspective back-end view of
element 11 of FIG. 6. Mouthpiece 100 is constructed by joining
elements 10 and 11, for example, with glue.
[0077] Element 10 has a curved member 15 with side walls 12 and 13
at the terminating edges of curved member 15, and a crescent-shaped
ledge 14 extending perpendicularly away from the convex surface of
member 15. Coordinates x, y, and z are included in FIG. 6 to assist
in describing the elements. With reference to these coordinates,
the concave surface of member 15 is symmetric about the x axis,
perhaps following a parabolic curve that might be defined by the
equation x=az.sup.2 for |y| y.ltoreq. and 0.ltoreq.z.ltoreq.z,
where a is a positive constant. Member 15 may be said to be concave
in the x and z dimensions, and linear in the y dimension. An
archway is thus formed by member 15 in the space where
0<x>az.sup.2. The crescent-shaped ledge 14 lies on the x-z
plane at y=-y, between the curve x=az.sup.2 and curve
x=(a+.DELTA.)z.sup.2-b, .DELTA. and b being positive constants. On
the concave surface of member 15 there is a plurality of
light-generating devices 16, for example, light emitting diodes
(LEDs). In FIG. 6, the LEDs are arranged in an array having
columns. Ledge 14 includes an array of holes 17.
[0078] Element 11 has a curved member 18 that has a slightly larger
curvature than the curvature of member 15 (e.g., following the
curve x=(a+.DELTA.)z.sup.2-b). Aside from being positive, the
constants .DELTA. and b are adjusted so that the vertical edges of
curved member 18 mate with the outside edges of walls 12 and 13
when the curved bottom curved edge of member 18 mates with the
outside curved edge of ledge 14. Element 11 also has an upper ledge
20 that the same shape as ledge 14. Thus, when elements 10 and 11
are mated, a hollow space is created within the resulting
mouthpiece 100.
[0079] Element 11 also has a circular opening 19 (see the
perspective back view of element 11 in FIG. 7) roughly at the
center of member 18 (shown in FIG. 6), and on the convex side of
member 18 there is a housing 23, substantially covering opening 19,
within which a fan 21 is installed. The fan is arranged so that
when elements 10 and 11 are mated and, as indicated above, a hollow
space is created within the mouthpiece, fan 21 causes air to be
drawn out of the hollow space of mouthpiece 100, with air being
sucked into the hollow space through the array of holes 17. This
air draws out the heat that is generated within mouthpiece 100 by
virtue of the inherent inefficiencies in converting electrical
energy to light (in the light-generating devices).
[0080] It should be understood that, with reference to the elements
described so far, the most important aspect of mouthpiece 100 is
the fact that light-generating devices are situated on the
mouthpiece and arranged to face the teeth of a patient. Other
relatively important aspects of the elements described so far are
the concave, substantially symmetric, surface of mouthpiece 100,
and the means for passing air through the mouthpiece.
[0081] A concave surface on which the light-generating devices are
placed is preferable because it more easily allows the creation of
a relatively uniform field of light intensity (power per unit area)
at a patient's teeth, which are situated within gums that form a
generally symmetric and convex surface. Other shapes are possible,
of course, with some being less conducive to focusing of light onto
a patient's teeth (for example, a flat surface 15), while others
being more conducive to focusing of light onto a patient's teeth
(for example, a surface that follows the equation
x=az.sup.2+by.sup.2, as shown in FIG. 8).
[0082] The means for passing air is advantageous because, at least
with present day technology, the known light-generating devices
that can be placed on surface 15 generate heat as a natural
by-product of the inefficiency associated with converting
electrical energy to light. One might think of it as "I.sup.2R
heat." It has been determined that it is best to remove this heat
by blowing air through mouthpiece 100, exiting away from the
patient's face. Accordingly, the disclosed embodiment includes
holes 17 and opening 19 at the back of element 11, housing 23 and
fan 21. This, of course, is merely illustrative, and other methods
for removing the heat may be employed. For example, housing 23 can
be merely a nipple to which a hose is attached. Fan 19 (or any
other device for creating a pressure differential) might be on the
remote end of the hose.
[0083] Returning to the description of the mouthpiece in FIG. 6 the
mouthpiece 100, side walls 12 and 13 include two light emitting
diodes each (31, 32, and 33, and 34, respectively) which are useful
for guiding the position of mouthpiece 100 in front of the
patient's teeth. These diodes may be conventional LEDs that emit
light in the visible range (e.g., red) and include focusing lens,
designed to create a light beam that points in a preselected
direction. Specifically, the light beams that are created by LED 31
and 32 are arranged to meet at a preselected point in space, and
that point may be selected to be on the surface of a patient's face
when mouthpiece 100 is positioned at its proper place relative to
the patient's mouth in order to achieve good teeth bleaching
results from the light emitted by the light-generating devices of
surface 15. To achieve such beam positioning, the bear created by
LED 31 may be tilted toward LED 32, and the beam created by LED 32
may be titled toward LED 31. Advantageously, the beams are focused
to a point at the very spot where the two beams (from LED 31 and
32, respectively) meet, but that is not a requirement. Collimated
beams can be used, as well as beams that diverge slightly. The
lenses required for creating the beams of LEDs 31 and 32 are
perfectly conventional. The pair of LEDs 33 and 34 are arranged in
the same way as the pair of LEDs 31 and 32. It should be understood
that using a pair of LEDs is merely illustrative. Even one LED may
be used, for example, if it is focused to effectively a point at a
predetermined distance from surface 15. Certainly, it is also
possible to use more than the two pairs of LEDs shown in FIG.
6.
[0084] Again, the positioning approach that involves the use of the
above-described LED pairs is merely illustrative. It has the
advantage of not requiring anything of the patient except sitting
still. Another illustrative positioning approach is suggested by
dimple 5 in FIG. 6. This approach, which is quite simple, requires
the patient to bite on a positioning device, not unlike bite block
6, depicted in FIG. 6, and requires the positioning of the end of
device 6 that is distal to the patient in dimple 5 of surface
15.
[0085] Directing attention to FIG. 7, housing 23 includes circular
indentations 24, which form the means for connecting mouthpiece 100
to an arm arrangement that is not unlike the conventional arm
arrangement to which a dentist's light is attached. Such an
arrangement includes an end piece for coupling housing 23, for
example, as illustrated in FIG. 9.
[0086] Ideally, in providing a catalytic light to the surface of a
patient's teeth, each portion of each tooth would get "just the
right amount of light." However, the situation presents many
variables that are difficult to control or ascertain (e.g. shape of
teeth, size of teeth, distance of teeth from the points of focus on
the patient's face, etc.) and, therefore, one has to deal with
"roughly the right amount of light." It has been found that a
reasonable goal in connection with the user of this invention to
provide a substantially uniform light intensity to all of the
teeth, and to direct as much of the available light to the
teeth.
[0087] Most devices that generate light do not generate collimated
light but, rather, create a light beam that expands with distance
from the light source. Ideal point sources generate light that is
uniform (in intensity) in all directions. That is, at any point in
space, the light intensity corresponds strictly to the distance of
the point from the point source. Stated differently, all points on
a hemisphere centered about the point source receive the same light
intensity. In two dimensions, this can be represented by a
semicircle centered on the point source, because the distance from
the center to any point on the semicircle (corresponding to the
magnitude of the intensity vector) is a constant. Non-ideal light
sources do not produce the same light intensity in all directions
and, typically, the highest intensity is some direction that is
related to the structure of the light-generating device. LEDs, for
example, typically produce the highest light intensity at a
direction that is perpendicular to the surface of the LED's
semiconductor substrate. In two dimensions, the light intensity
profile of a non-ideal light-generating device might be something
not unlike curve 51 of FIG. 100. At angles close to the
aforementioned perpendicular, the light intensity--represented by
the length of the vector from the origin to curve 51 is high. At
angles significantly away from the perpendicular, the light
intensity is lower; and at angles that are close to 90.degree. from
the perpendicular, the light intensity is practically zero. The
light emanating from ideal, as well as non-ideal, light sources can
be focused with a lens, for example, to generate a light intensity
profile curve more like curve 52. It should be remembered, by the
way, that curves 51 and 52 are a light intensity profile curves
when viewed in two dimensions. They represent three-dimensional
surfaces (akin in shape to hot air balloons) that are often
referred to as "lobes."
[0088] Given a light intensity profile curve, and given that the
light-generating devices 16 in a row on surface 15 (i.e., on an x-z
surface) are spatially separated from each other, if the
light-generating devices 16 are non-coherent, the light intensity
profile that results from a plurality of lights along a row on
surface 15 corresponds to the power addition of the individual
light intensity profile curves. To illustrate, FIG. 11 shows
light-generating devices 52, 53, 54 and 55 (with appropriate
lenses) within a row on surface 15 that generate light beams with
light intensity profile curves 56, 57, 58 and 59, respectively.
Those light beams add (power addition) so that at point 60, for
example, the light intensity corresponds to a sum of three factors:
one related to the length of vector 61, one related to the length
of vector 62, and one related to the length of vector 63. Note that
beam 59 contributes no light at point 60. At point 68, for example,
the light intensity corresponds to a sum of four factors: one
related to the length of vector 64, one related to the length of
vector 65, one related to the length of vector 66, and one related
to the length of vector 67.
[0089] It is noted that FIG. 11 shows all of the light-generating
devices producing identical light intensity curves that are
symmetric about an axis of symmetry (e.g. axis 69 of curve 59).
Moreover, the axes of symmetry are perpendicular to the tangent of
curve 15 at the situs of the light sources (e.g., source 55). Given
that a generally uniform light intensity is desired at a surface of
the patient's teeth, a designer of mouthpiece 100 has numerous
parameters under his or her control that allow the designer to
achieve this goal. That includes: [0090] the curvature of surface
15; [0091] the spacings between the light-generating devices along
a row of surface 15 (which do not have to be uniform); [0092] the
overall light intensity emitted by the individual light-generating
devices (both, buying light-generating devices that produce
different amounts of light for a given amount of driving current,
and driving the light-generating devices with different amounts of
driving current); [0093] the shapes of the light intensity profile
curves (controlled by the lens of the light-generating devices);
and [0094] the directions of the axes of symmetry of the individual
light-generating devices.
[0095] It should be also remembered that the light produced by the
light-generating devices serves as a catalyst that speeds up the
bleaching process in teeth whitening, and that time of exposure is
also a variable that can be employed. That is, it bears remembering
that it is not just light intensity per se that is important, but
the integral of the light intensity over time that is
important.
[0096] The discussion above basically addresses the two dimensions
represented by the x and z axes of FIG. 6. Of course, mouthpiece
100 is a three-dimensional object with light-generating devices
both in rows along the curvature of surface 15, and in columns that
are perpendicular to the rows. Further, the generally uniform light
intensity that is desired is over a surface in which the patient's
teeth are found; which is a surface that is roughly convex in the
x-z axes, and roughly independent of position along they axis,
within a certain distance from the origin. In other words, it is a
surface that roughly mates with surface 15. If the light-generating
devices are capable, in aggregate, of generating a sufficiently
intense light, in the range of 10 to 300 mw/cm.sup.2 at the surface
of the teeth, and if the lens that are integral with the
light-generating devices are designed to provide--when aggregated
over the row of light-generating devices--a substantially uniform
light on the upper and lower teeth of a person, as shown in FIG.
12, then a single row of light-generating devices in mouthpiece 100
would suffice.
[0097] The above-mentioned range of light intensities is fairly
broad, but that is because the duration of time that light needs to
be applied to a patient's teeth or order to get a specific
beneficial results is inversely proportional to the intensity of
light applied to a patient's teeth. Hence, with a low intensity of
light the procedure takes a long time, and with a high intensity of
light the procedure takes a short time. While a simple tradeoff of
time for intensity is technically acceptable, it has been concluded
that the above-mentioned range comes close to the commercially
acceptable procedure-time limits. We find that an intensity that is
nominally set at 130 mw/cm.sup.2 (i.e., 130.+-.10 mw/cm.sup.2)
works well to get a beneficial result in one hour. Higher
intensities are, of course, permitted to be used, and we believe
that a light intensity of as much as 200 mw/cm.sup.2 is still
safe.
[0098] Aside from the commercial notion that one might not wish to
have a procedure that takes hardly any time, because it is
difficult to charge a reasonable fee therefor, in today's
technology there is an additional reason to be concerned with very
high intensities, and that is heat. That is, although the
physiological effects of heat are most pronounced for radiation in
the infrared (IR) wavelengths of light (750 nm to 2,500 nm), there
is some perception of heat at somewhat shorter wavelength as well.
The light wavelengths at which the light-sensitive bleaching gels
used in today's practice benefit from the application of light are
in the 300 to 900 nm range. Clearly, there is an overlap between
wavelengths at which the bleaching gels are effective, and
wavelengths that produce heat. Compounds can be selected that are
most strongly activated with light that is closer to the
blue/violet side of visible light, and heat from sources that
produce such a light does not present a problem. However, even
light sources that produce a preponderance of light intensity in
the blue/violet range nevertheless produce some light in the IR
range and, moreover, produce a fair amount of heat from the
inefficiencies in the conversion of electrical energy into light.
Further some devices (such as LEDs) are current devices that are
typically controlled with a voltage and a series resistor, and such
resistors produce heat. That heat is extracted from mouthpiece 100,
as described above, with fan 21.
[0099] We have discovered that the objects of this invention can be
satisfied with LEDs that produce light having a bulk of their
energy in the range of 475.+-.40 nm. Such LEDs can be obtained, for
example, from the US distributor of Nichia (a Japanese LED
manufacturer). It is noted that the Nichia LEDs can be obtained
with two types of integral lenses. One that produces a cone of
15.degree., and one that produces a cone of 30.degree.. A cone of
15.degree. means that the angle .alpha. (see FIG. 11) between the
center of symmetry and the point along the light intensity profile
curve where the intensity is one half the peak intensity is
7.5.degree..
[0100] Returning to the question of the necessary number of rows of
light-generating devices on surface 15, with today's technology it
is unlikely that a single row of devices would suffice (from the
standpoint of the light intensity that can be generated from an
LED) and, because of that, the FIG. 6 mouthpiece is shown with a
plurality of light-generating devices arranged in columns. FIG. 13
shows an arrangement where a column of light-generating devices has
only two devices: 56 and 57. With a reasonably simple lens design
the row of light-generating devices that contains device 56 can
handle the upper teeth of a patient (e.g., tooth 71 attached to
upper gum 72), and the row of light-generating devices that
contains device 57 can handle the lower teeth of a patient (e.g.,
tooth 73 attached to lower gum 74). If one row of devices (per
tooth) is not sufficient because of light power output limitations
of the devices used, or because a single device cannot provide the
desired uniformity of light intensity on the teeth, a plurality of
light-generating devices that is greater than two devices per
column might be used, and appropriately focused. One might note
that the light profile of the light-generating devices of FIG. 12
is broader and more flattened (i.e., more equal intensity) in the
neighborhood of an axis that is perpendicular to surface 15 than
the light profile of the light-generating devices of FIG. 13. This
intends to demonstrate the flexibility that a design of the lenses
that are placed in front of the light source (whether integral to
the light-generating device, and/or positioned in front of the
light-generating devices) can impart.
[0101] FIG. 14 shows an arrangement where 5 LEDs in a column are
focused with appropriate lens incorporated in the individual LEDs.
When the LED's that can be obtained have built-in lens that output
a light beam whose axis of symmetry is perpendicular to the
substrate of the LED, then the lobe of the LEDs need to be angled
by some other means. One embodiment positions additional lens in
front of the LEDs so as to tilt the generated beam in the desired
direction. Another embodiment angles the LEDs, as shown in FIG. 14,
by means of angling, triangular shaped, pedestals 81 that produce
the appropriate tilting. Incorporating the proper angling within
the curved surface of member 15 may attain the same results. That
is, there is no requirement that the surface of member 15 needs to
be a simple, smooth, mathematical curve. Yet another embodiment,
which angles the LEDs employs a curved surface like the one
depicted in FIG. 8, is shown in FIG. 15. We found that largest
angle that is useful to direct a lobe away from the perpendicular
is about 15.degree..
[0102] The FIG. 6 arrangement of the light-generating devices
creates a two dimensional array of devices (if surface 15 is
"flattened out"). This arrangement, which is also shown in FIG. 16
is not a requirement. The lights can form any desired pattern and,
for example, a uniform light intensity pattern may be more easily
achieved with a staggered pattern like the one shown in FIG. 17, or
even a "honeycomb" pattern.
[0103] Regardless of the pattern that is employed, and whether
surface 15 is straight, like illustrated in FIG. 13; with angling
pedestals like illustrated in FIG. 14, curved like illustrated in
FIG. 15, or has a complex shape where different points on the
surface have specified normals that are dictated by the directions
in which the light lobes need to be pointed to in order to get a
uniform light intensity field, the LEDs, can be easily placed on
surface 15. That is, the LEDs can be purchased separately (each of
which has two electrical leads), surface 15 can be manufactured
with a pair of feed-through holes for each LED, and the LEDs are
installed by feeding the leads of the LEDs through the feed-through
holes.
[0104] FIG. 18 shows a portion of the back view of element 10, with
a column of printed-circuit type feed-through holes 24 for the
anodes of the LEDs in a column, and an adjacent column of
printed-circuit type feed-through holes 25 for the cathode of the
LEDs in a column. Holes 24 are connected to bus 26, and holes 25
are connected to bus 27. Buses 26 and 27 are connected to
electrical terminals (not shown) through which power is supplied to
buses 26 and 27. When the LEDs are inserted into holes 24 and 25
and soldered to the feed-through holes, the construction is
complete. It may be noted that LEDs are current devices, in the
sense that the light output is a function of the LED current. To
impart accurate control over the currents of the individual LEDs, a
series current circuit (as simple as a resistor) is advantageously
included with each LED, allowing the energy applied to buses 26 and
27 to be a controlled voltage. The current circuit, which is a
well-known electrical element is not shown in FIG. 18 for sake of
simplicity.
[0105] The drawing depicted in FIG. 18 employs a common electrical
control of the LEDs inserted into surface 15. A control that is
different for each different row, or for each different column of
the LEDs is easily implemented with a different wired arrangement
on the back end of element 10, including electronic circuits that
are placed within the hollow space of mouthpiece 100 to provide
individual power control of the LEDs. The electronic circuits can
be analog, providing a light intensity control via the magnitude of
the voltage applied to the LEDs, or can be digital, providing a
light intensity control via duration control of the voltage of the
LEDs.
[0106] LED's are generally considered to be very reliable, at least
with respect to whether they generate light or not. It is expected
that they will not be as reliable with respect to the intensity of
the light output. While mouthpiece 100 is fairly inexpensive, in
and of itself, there may be arrangements where it would be
disadvantageous to replace the entire mouthpiece when one, or a few
LEDs start to generate light at below some expected intensity. This
is true, for example, when mouthpiece 100 is an integral part of an
entire arm assembly. FIG. 19 presents an arrangement where the
columns of LEDs are slideably coupled to mouthpiece 100. That is, a
plurality of LEDs are manufactured on circuit board strips that are
somewhat flexible, as depicted in FIG. 19, with printed circuit
board leads on the back, in a manner not unlike the one shown in
FIG. 18. Those strips are slid into troughs 36 in surface 15 of
element 10 to form mouthpiece 100, and when the strips are properly
positioned in troughs 36, the anode and cathode leads of the strip
make contact with corresponding contacts on the back of surface 15
to provide the electrical power. Element 10 in the FIG. 19
embodiment needs to be somewhat thicker than element 10 in the FIG.
6 embodiment (when troughs are used), but the difference is not
significant.
[0107] FIG. 20 shows a slightly different embodiment. Instead of
sliding in LED-laden strips effectively within surface 15 of
element 10, small circuit boards 37 that have edge-mounted LEDs are
inserted into element 10 effectively perpendicularly to surface 15
of element 10.
[0108] FIG. 6 aims to cover all of the patient's teeth at once.
While that is a salutary goal, there are times when only one, or a
few, of a patient's teeth need to be whitened. A modified version
of the FIG. 6 assembly can be created using the principles
disclosed herein, basically employing an assembly with
light-generating devices on the assembly, and the light-generating
devices--such as LEDs--being selected to produce light in the
spectral range disclosed above, focused, and directed so that the
lobes of light generated by the LEDs overlap at a preselected
distance form the assembly. A health-care professional can then
apply the assembly at this preselected distance from the tooth, or
teeth of the patient. When it is desired to use such an assembly to
whiten the entire set of a patient's teeth, the health-care
professional can scan the device over the teeth.
[0109] The inventive apparatus, when constructed with multiple
LED's arranged in a manner to focus light on the surface of the
teeth, demonstrates a surprising phenomenon. A focused LED array,
having many relatively low power density point sources of light,
creates a "sweet spot" region of higher power density in the
vicinity of the focal plane (in the case of an arcuate LED array
apparatus for doing tooth whitening, the focal plane has a
curvature which runs more or less parallel to the surface of the
patient's teeth). A focused LED array can be designed to provide
the highest power density within the sweet spot; a patient is then
positioned so that her teeth fall within this area to obtain the
best effects from the light energy. Not only does the light energy
decrease as the patient's teeth are moved further from the focused
LED array, but light energy also decreases when the patient's teeth
are moved closer to the LED array. This phenomenon provides a high
margin of safety for the patient, if the patient accidently comes
too close to the LED array, the power density would be less than
that in the sweet spot.
[0110] The above discloses the principles of this invention by way
of illustrative embodiments. It should be understood that various
modifications and additions might be introduced by persons skilled
in the art without departing from the spirit and scope of this
invention, which is delineated by the appended claims. For example,
an additional control variable over the light-generating devices is
the size of the devices used (e.g., LEDs with larger, or smaller,
active areas). Also, different LEDs in the assembly can be selected
to have different spectral ranges.
[0111] Further, the positioning of the light-generating devices on
the curved surface is shown to be with feed-through holes and with
slideable strips. Clip-on strips can also be used. More
interestingly, surface 15 can include means to attach a flexible
membrane on which the entire plurality of LEDs can be manufactured,
for example through a semiconductor growth process. Still further,
while the above discusses creating a field of uniform intensity,
embodiments may be created to provide whatever light intensity
profile may be desired. Yet further, the entire assembly of
elements 10 and 11 can be manufactures to allow some flexibility in
the shape of curved surface 15. This allows for tailoring of the
FIG. 6 device to the shape of the mouth of different patients.
[0112] Further, in embodiments where lenses that are not integral
to the light-generating means are employed, the lenses can be
created as a group, within a clear membrane that is positioned in
front of member 15.
[0113] The following examples set forth preferred embodiments of
the invention. These embodiments are merely illustrative and are
not intended to, and should not be construed to, limit the claimed
invention in any way.
EXAMPLE I
[0114] In order to determine the ability of the inventive
compositions to eliminate tooth stain, a preliminary in vitro study
on stained bovine enamel was performed. Squares of dental enamel 4
mm on a side were cut, using a diamond-cutting disk, from bovine
permanent incisors. Using a mold, the enamel squares were embedded
in clear polyester casting resin (NATCOL Crafts Inc., Redlands,
Calif.) to provide 1.5 cm square blocks with the labial surface
exposed. The top surface of the polyester blocks was ground flush
with the leveled labial surface of the enamel squares by means of a
dental model trimmer. The surface was then smoothed by hand sanding
on 400-grit emery paper using water as the lubricant until all
grinding marks were removed. Finally, the top surface of the blocks
was hand polished to a mirror finish using a water slurry of GK1072
calcined kaolin (median particle size=1.2 microns) on a cotton
cloth. The finished specimens were examined under a dissecting
microscope and were discarded if they had surface
imperfections.
[0115] In preparation for the formation of artificial stained
pellicle on the enamel, the specimens were etched for 60 seconds in
0.2M HCl followed by a 30-second immersion in a saturated solution
of sodium carbonate. A final etch was performed with 1% phytic acid
for 60 seconds, then the specimens were rinsed with deionized water
and attached to the staining apparatus.
[0116] The pellicle staining apparatus was constructed to provide
alternate immersion into the staining broth and air-drying of the
specimens. The apparatus consisted of an aluminum platform base
which supported a Teflon rod (3/4 inch in diameter) connected to an
electric motor, which by means of a speed reduction box, rotated
the rod at a constant rate of 1.5 rpm. Threaded screw holes were
spaced at regular intervals along the length of the rod. The tooth
specimens were attached to the rod by first gluing the head of a
plastic screw to the back of a specimen. The screw is then
tightened within a screw hole in the rod. Beneath the rod was a
removable, 300-ml capacity trough, which held the pellicle,
staining broth.
[0117] The pellicle staining broth was prepared by adding 1.02
grams of instant coffee, 1.02 grams of instant tea, and 0.75 grams
of gastric mucin (Nutritional Biochemicals Corp., Cleveland Ohio
44128) to 250 ml of sterilized trypticase soy broth. Approximately
50 ml of a 24-hour Micrococcus luteus culture was also added to the
stain broth. The apparatus, with the enamel specimens attached and
the staining broth in the trough was then placed in an incubator at
37.degree. C. with the specimens rotating continuously through the
staining broth and air. The staining broth was replaced once every
24 hours for ten consecutive days. With each broth change the
trough and specimens were rinsed and brushed with deionized water
to remove any loose deposits. On the eleventh day the staining
broth was modified by the addition of 0.03 grams of
FeCl.sub.3.6H.sub.2O, and this was continued with daily broth
changes until the stained pellicle film on the specimens was
sufficiently dark. Then the specimens were removed from the
staining broth, brushed thoroughly with deinonized water, and
refrigerated in a humidor until used.
[0118] Absorbance measurements over the entire visible spectrum
were obtained using the CIELAB color scale (Commission
International de L'Eclairage, Recommendations on uniform color
spaces, color difference equations, and psychometric color terms,
Supplement 2 to CIE publication 15 (E-13.1) 1971 (TC-1.3), 1978,
Paris: Beaurea Central de la CIE, 1978). The CIELAB color scale
evaluates color in terms of three axes of a color sphere, called L,
a, and b. The "L" value is the axis in the color sphere which
relates lightness and darkness on a scale from 0 (black) to 100
(white). The "a" value is the axis which relates color on a yellow
to blue scale, with a 0 value in the center of the sphere, positive
values toward the yellow, and negative values toward the blue. The
"b" value is the axis which relates color on a red to green scale,
with a 0 value in the center of the sphere, positive values toward
the red, and negative values toward the green.
[0119] The stained enamel specimens were allowed to air-dry at room
temperature for at least one hour before absorbance measurements
were made. Measurements were conducted by aligning the center of a
4-mm square segment of stained enamel directly over the 3-mm
aperture of the Minolta spectrophotometer. An average of 3
absorbance readings using the L*a*b* factors were taken for each
specimen.
[0120] The difference between the pre-treatment (baseline) and
post-treatment readings for each color factor (L*, a*, and b*)
represented the ability of a test solution to eliminate chromogens
from the stained teeth.
[0121] The overall change in color of stained pellicle was
calculated using the CIELAB equation
.DELTA.E=[(.DELTA.L*).sup.2+(.DELTA.a*).sup.2+(.DELTA.b*).sup.2].sup.1/2
A "Corrected .DELTA.E" value was calculated by eliminating from the
above formulation the contribution of any positive .DELTA.a or
.DELTA.b values (positive .DELTA.a and .DELTA.b values are changes
in tooth color in the opposite direction from zero, and hence
construed to add color, rather than remove it).
[0122] The following oxidizing composition was prepared, which
contained approximately 15% by weight hydrogen peroxide and 1
percent by weight of the photosensitizer precursor
1-hydroxyethylidene-1,1'-diphosphonic acid (Dequest 2010, Monsanto
Corp., St. Louis, Mo.). Highly purified water (18.2 megaohm,
filtered through a 0.2 micron filter) was utilized in order to
maintain good stability of the composition during storage. The
composition was thickened with a carboxypolymethylene polymer
(Carbopol 974P, B.F. Goodrich Co., Cleveland, Ohio) to the
consistency of a light, non-runny gel. Glycerin was added in a
small percentage as a humectant and stabilizer (as a free radical
scavenger), and the Carbopol 974P was neutralized to a pH of 5.00
with ammonium hydroxide, resulting in the formation of a
transparent and thixotropic gel. TABLE-US-00001 Ingredient
Percentage Distilled water 49.400
1-hydroxyethylidene-1,1-diphosphonic acid 1.000 Glycerin 99.7%
5.000 Hydrogen peroxide 35% 42.900 Carbopol 974P 1.700 Ammonium
hydroxide 29% to pH 5.5 TOTAL 100.000
[0123] The above composition was prepared in a plastic mixing
chamber by combining, under agitation with a Teflon-coated mixing
paddle until a clear solution was obtained, the distilled water,
the 1-hydroxyethylidene-1,1-diphosphonic acid, and the glycerin.
The Carbopol 974P was then sifted slowly into the vortex created by
the mixing paddle and allowed to mix until a homogeneous slurry of
the polymer was obtained. Finally, the ammonium hydroxide was added
in a constant, dropwise fashion over a period of about 5 minutes
until thickening and clarification of the slurry occurred. A pH
probe was inserted periodically and the ammonium hydroxide addition
proceeded until a pH of exactly 5.00 was obtained. The resulting
gel contained 15% by weight hydrogen peroxide, and was highly
transparent and thixotropic (non-slumping) in character.
[0124] Each stained bovine enamel slab was coated with a 1-2 mm
film of the composition in Example I above for a specified period
of time and exposed to actinic radiation from one of several light
sources. Table 1 below shows some comparative results obtained by
exposing gel-treated enamel slabs to either Argon plasma arc (AR)
or tungsten halogen (TH) light sources. This particular protocol
called for the fiber optic light guide to be placed 5 mm from the
surface of the enamel during light exposures. The energy of each
pulse was adjusted with a power density meter prior to each
exposure regimen and measured again after each regimen to verify
consistent output of the light source over the duration of the
test. The results are listed in Table 1 below: TABLE-US-00002 TABLE
1 Bovine Light Total Gel Number of Energy/Pulse Corrected Tooth #
Source Contact Time Pulses (Joules) Delta E* B311 None 30 min 0
0.00 12.76 B388 AR None 30 1.66 1.41 B277 AR 30 min 30 1.66 29.28
B214 AR 30 min 30 3.35 29.75 B283 AR 10 min 10 3.29 18.62 B147 AR
10 min 10 4.90 25.98 B401 AR 10 min 30 4.97 32.18 B211 AR 5 min 15
4.84 20.05 B213 AR 5 min 30 4.93 31.02 B35 TH 5 min 15 1.29 12.88
B35 TH 5 min 15 1.29 19.39 B35 TH 5 min 15 1.29 20.01 B35 TH 5 min
15 1.29 23.61 B35 TH 5 min 15 1.29 25.35 B35 TH 5 min 15 1.29 26.41
*Elimination of positive .DELTA.a and .DELTA.b values from
calculation
[0125] The data in Table 1 demonstrates that:
[0126] (1) In the in vitro model described, exposure of bovine
enamel slabs, contacted with the inventive gel composition above,
to pulsed actinic radiation from a Argon plasma arc light source
resulted in significantly reduced tooth stain as compared to slabs
treated either with just gel alone (and not exposed to the light
source) or light source exposure only (no gel).
[0127] (2) Six sequential treatments (over 30 minutes) of a single
stained bovine enamel slab (B35) with gel and concurrent exposure
of said slab to pulsed actinic radiation from a tungsten halogen
light source (5 minute exposure periods) resulted in an increasing
level of tooth stain removal over the period of the test. The
result was significantly lighter in color than that achieved in
tooth number B311, which was also in contact with the inventive gel
composition, but did not get exposed to a light source.
EXAMPLE II
[0128] A comparative study of light transmission through various
light and/or heat activated tooth whitening gels was undertaken.
Spectral energy curves were generated using an Ocean Optics
spectrometer with a 50 micron fiber for gather emission data. Light
transmission through a glass microscope slide was used as a control
and the test consisted of coating the slide with a 1-2 mm thick
layer of each tooth whitening gel and illuminating with a metal
halide light source connected to an 8 mm glass fiber optic light
guide. The light was filtered through a 505 nm short pass filter
(only wavelengths less than 505 nm pass through) prior to entering
the light guide. The spectrometer's fiber optic probe was placed
against the opposite side of the slide from the gel in order to
detect the wavelengths of light allowed to pass through the gel on
the slide. The spectral curves of FIGS. 4 A-E clearly demonstrate
the degree of light attenuation caused by all of the commercially
available compositions. The spectral curves of FIGS. 4 A-E clearly
demonstrate the degree of light attenuation caused by all of the
commercially available compositions: FIG. 4A--Control, FIG.
4B--Inventive Example I; FIG. 4C--Shofu Hi-Lite; FIG.
4D--QuasarBrite; Figure E-Opalescence Xtra.
[0129] The attenuation of power density, measured in mW/cm.sup.2,
was determined for the same four compositions by again placing a
1-2 mm layer of each gel or paste on a glass microscope slide and
placing the slide/gel assembly in the path between the light source
and the detector well of the power density meter. Due to the depth
and shape of the detector well, the slide was 7 mm above the actual
detector surface, rather than directly in contact with it. The
power density was recorded at the beginning (B) and at the end of a
60 minute light exposure (E). The power density without slide or
gel in the light path was adjusted to 175 mW/cm.sup.2. The results
are shown in Table 2 below. TABLE-US-00003 TABLE 2 Energy Density
Composition U.S. Pat. No. (m W/cm.sup.2) Control (slide only) --
165 Example I (B) + (E) -- 160 & So Shofu Hi-Lite (B) 5,032,178
25 Shofu Hi-Lite (E) 5,032,178 50 QuasarBrite (B) 5,240,415 110
QuasarBrite (E) 5,249,415 111 Opalescence Xtra (B) 5,785,527 65
Opalescence Xtra (E) 5,785,527 94
EXAMPLE III
[0130] Another transparent hydrogen peroxide gel was prepared that
had a lower concentration of oxidizer (3% by weight of
H.sub.2O.sub.2), but at a pH of 7.0 and a much higher viscosity
(approximately 1,000,000 cps). The gel below was prepared in
accordance with the procedure in Example I, except that a Kynar
coated Ross Double Planetary vacuum mixer (Charles Ross & Sons,
Haupaugge, N.Y.) was used to handle the elevated viscosity achieved
during and after neutralization with the ammonium hydroxide. Sodium
stannate was added as an additional stabilizer for the hydrogen
peroxide. TABLE-US-00004 Ingredient Percentage Distilled water
81.010 Glycerin 99.7% 5.000 1-hydroxyethylidene-1,1-diphosphonic
acid 0.400 Sodium stannate 0.015 Hydrogen peroxide 35% 8.570
Carbopol 974P 5.000 Ammonium hydroxide 29% to pH 7.0 TOTAL
100.000
[0131] The ability of the 3% hydrogen peroxide gel, transparent to
visible light between the wavelengths of 380 and 700 nanometers, is
demonstrated in Table 3 below. TABLE-US-00005 TABLE 3 Wavelength
Power Energy/ Bovine Oxidizing Time Light Range Pulses/ Density
Pulse Tooth # Gel Period Source (nanometers) Period (mW/cm2)
(Joules) Delta E* B388 Example II 5 min AR 380-505 15 4.84 19.67
B388 Example II 5 min AR 380-505 15 4.84 29.43 B388 Example II 5
min AR 380-505 15 4.84 32.74 B365 Example II 5 min None -- 0 0 3.41
B365 Example II 5 min None -- 0 0 4.23 B365 Example II 5 min None
-- 0 0 5.78 B365 Example II 5 min AR 380-505 15 4.84 23.49 B365
Example II 5 min AR 380-505 15 4.84 30.27 B367 Example I 30 min TH
400-520 Continuous 250 32.26 *Elimination of positive .DELTA.a and
.DELTA.b values from calculation.
EXAMPLE IV
[0132] Extracted human teeth (HE) that were non-carious and free of
amalgam or resin-based restorative materials were utilized to study
the ability of the inventive compositions to eliminate the stains
from human enamel and dentin. The teeth were coated with a 1-2 mm
thick film of an oxidizing gel and irradiated according to the
regimens shown in Table IV below. The resulting change in tooth
color (.DELTA. Shades) was recorded as the number of VITA.RTM.
shade difference between the original baseline VITA.RTM. shade
value and the final VITA.RTM. shade value. TABLE-US-00006 TABLE 4
Light Exposure Pulses/ Joules/ Shade Shade .DELTA. Tooth # Gel
Source Time (min) Minute Pulse (Initial) (Final) Shade: HE2 Example
I AR 30 1 4.84 B4 C2 6 HE3 Example I AR 30 1 4.84 A4 A3.5 3 HE4
Example I AR 30 1 4.84 A3 B2 6 HE5 Example I AR 30 1 4.84 B3 D4 3
HE6 Example I AR 30 1 4.84 B3 B2 8 HE7 Example I AR 30 1 4.84 A3 A1
7 HE8 Example I AR 30 1 4.84 A3.5 A2 7 HE9 Example I AR 30 1 4.84
A3 A1 7 HE10 Example I AR 30 1 4.84 A4 A3.5 6 HE11 Example I AR 30
1 4.84 A3.5 A2 7 HE12 Example I AR 30 2 4.84 A3.5 A2 7 HE13 Example
I AR 30 2 4.84 B3 B2 8 HE14 Example I AR 30 2 4.84 A3.5 B2 9 HE15
Example I AR 30 2 4.84 A4 A1 13 HE16 Example I AR 30 2 4.84 B4 B1
12 HE17 Example I AR 30 1 1.64 A3 A2 4 HE18 Example I AR 30 1 1.64
B4 B2 10 HE19 Example I AR 30 1 1.64 C4 D3 6 HE20 Example I AR 30 1
1.64 B3 A2 6 HE21 Example I AR 30 1 1.64 B3 B2 8 HE22 Example I No
light 30 0 0 B3 A2 2 HE23 Example I No light 30 0 0 A3 A2 4 HE24
Example I No light 30 0 0 B3 D4 3 HE25 Example I No light 30 0 0 D3
B2 7 HE26 Example I No light 30 0 0 B3 A2 6 HE27 Example I Tungsten
60 Continuous 250 B3 A1 9 Halogen mW/cm2
EXAMPLE V
[0133] Human extracted teeth were whitened as follows by applying a
1-2 mm thick film of gel on the enamel surface and exposing the
same surface to varying power densities from a metal halide light
source with a 505 nm short pass internal filter. Comparisons were
done to two controls, one of which was Gel exposure only (no light)
and light exposure only (no Gel). Exposure regimens, consisting of
gel application (except in the case of light only/no Gel), followed
by 20 minutes of continuous light exposure, were repeated three
times (3.times.20 minutes) TABLE-US-00007 TABLE 5 Power Light
Density Test Initial Final Shade Tooth # Gel Source (mW/cm2) Filter
Duration Shade Shade Change HE101 Example I MH 250 505 3 .times. 20
min A3.5 A1 7 HE102 Example I MH 250 505 3 .times. 20 min B4 A2 8
HE103 Example I MH 175 505 3 .times. 20 min A3 B1+ 8 HE104 Example
I MH 175 505 3 .times. 20 min A4 B2 12 HE105 Example I MH 175 505 3
.times. 20 min B3 B2 8 HE106 Example I MH 175 505 3 .times. 20 min
A3 B1+ 8 HE107 Example I MH 175 505 3 .times. 20 min A4 A2 10 HE108
Example I No light 3 .times. 20 min A3.5 A3 3 HE109 Example I No
light 3 .times. 20 min A4 D3 5 HE110 Example I No light 3 .times.
20 min A3.5 A3.5 0 HE111 Example I No light 3 .times. 20 min A4 A3
6 HE112 Example I No light 3 .times. 20 min A4 A3.5 3 HE113 None MH
175 505 3 .times. 20 min A3 A3 0 HE114 None MH 175 505 3 .times. 20
min A4 A4 0 HE115 None MH 175 505 3 .times. 20 min A3.5 A3 3 HE116
None MH 175 505 3 .times. 20 min B3 B3 0
EXAMPLE VI
[0134] A pulpal chamber of an endo-tooth in a cooperative and
informed patient was wired using a thermal probe and
thermo-conducting paste. Pulpal temperatures were measuring during
an actual whitening procedure, in which the illumination was
supplied using the currently available Union Broach Illuminator and
the device described in the instant application used at the most
preferred wavelengths of 400 to 505 nanometers. Measurements of the
energy densities at the tooth surface showed comparable energy
densities for each device (230 milliwatts/cm.sup.2 for the Union
Broach Illuminator and 200 milliwatts/cm.sup.2 for the device
described in the instant application, respectively). The results
are shown below in Table 6.
[0135] Illumination using the device described in the instant
application in the preferred wavelength range from about 400 to 505
nanometers raised pulpal chamber temperature less than did the
Union Broach device. In this experiment, temperatures rose to a
maximum by twenty minutes and were then stable. In contrast to the
temperature rise seen with the Union Broach device, at no time did
the temperature using the device disclosed in the instant
application rise above the 5.5.degree. C. which could result in
thermally induced pulpitis if maintained for a significant period
of time. The temperature changes seen are likely to be greater than
those seen with vital teeth as endo-teeth have no blood supply to
provide additional cooling. TABLE-US-00008 Temperature Rise Time
(deg. C. from ambient) (min.) Union Broach BriteSmile 2000 5 4 2.9
10 8 4.5 15 9 5.3 20 9 4.2 25 9.5 4.5 30 9 4.3
EXAMPLE VII
[0136] In order to determine the ability of the inventive apparatus
described in FIGS. 6-20 to catalyze a light-activated tooth
whitening gel and eliminate tooth stain, an in vitro study on
stained bovine enamel was performed. Stained bovine enamel slabs
were obtained that had been prepared as described in Example I
above.
[0137] Enamel surface reflectance measurements over the entire
visible spectrum were obtained using the CIELAB color scale
(Commission International de L'Eclairage, Recommendations on
uniform color spaces, color difference equations, and psychometric
color terms, Supplement 2 to CIE publication 15 (E-13.1) 1971
(TC-1.3), 1978, Paris: Beaurea Central de la CIE, 1978). The CIELAB
color scale evaluates color in terms of three axes of a color
sphere, called L, a, and b. The "L" value is the axis in the color
sphere which relates lightness and darkness on a scale from 0
(black) to 100 (white). The "a" value is the axis which relates
color on a yellow to blue scale, with a 0 value in the center of
the sphere, positive values toward the yellow, and negative values
toward the blue. The "b" value is the axis which relates color on a
red to green scale, with a 0 value in the center of the sphere,
positive values toward the red, and negative values toward the
green.
[0138] The stained enamel specimens were allowed to air-dry at room
temperature 60 seconds before reflectance measurements were made.
Measurements were conducted by aligning the center of a 4-mm square
segment of stained enamel directly over the 3-mm aperture of the
Minolta 503i reflectance spectrophotometer. An average of 5
reflectance readings using the L*a*b* factors were taken for each
specimen.
[0139] The difference between the pre-treatment (baseline) and
post-treatment readings for each color factor (L*, a*, and b*)
represented the ability of the inventive LED array apparatus, in
conjunction with the light-activated tooth whitening gel
composition described below, to eliminate chromogens from the
stained bovine teeth.
[0140] The overall change in color of stained pellicle was
calculated using the CIELAB equation
.DELTA.E=[(.DELTA.L*).sup.2+(.DELTA.a*).sup.2+(.DELTA.b*).sup.2].sup.1/2
[0141] A "Corrected .DELTA.E" value was calculated by eliminating
from the above formulation the contribution of any positive
.DELTA.a or .DELTA.b values (positive .DELTA.a and .DELTA.b values
are changes in tooth color in the opposite direction from zero, and
hence construed to add color, rather than remove it).
[0142] The light-activated tooth whitening composition used in
conjunction with the inventive apparatus contained approximately
15% by weight hydrogen peroxide and 0.30 percent by weight of the
photosensitizer precursor 1-hydroxyethylidene-1,1-diphosphonic acid
(Dequest 2010, Monsanto Corp., St. Louis, Mo.). Highly purified
water (18.2 megaohm, filtered through a 0.2 micron filter) was
utilized in order to maintain good stability of the composition
during storage. An additional stabilizer, potassium stannate, was
also present in the mixture at a concentration of 0.02% by weight.
The composition was thickened with a carboxypolymethylene polymer
(Carbopol 974P, B.F. Goodrich Co., Cleveland, Ohio) to the
consistency of a light, non-runny gel. Glycerin was added in a
small percentage as a humectant and stabilizer (as a free radical
scavenger), and the Carbopol 974P was neutralized td a pH of 6.50
with ammonium hydroxide, resulting in the formation of a
transparent and thixotropic gel. TABLE-US-00009 TABLE 6 Ingredient
Percentage Distilled water 75.830
1-hydroxyethylidene-1,1-diphosphonic acid 0.300 Potassium stannate
0.020 Glycerin 5.000 Hydrogen peroxide 15.000 Carbopol 974P 1.700
Ammoniuin hydroxide 29% (add until 2.150 pH = 6.5) TOTAL
100.000
[0143] The above composition was prepared initially in a plastic
mixing chamber by combining, under agitation with a Teflon-coated
mixing paddle the distilled water, the
1-hydroxyethylidene-1,1-diphosphonic acid, the potassium stannate,
and the glycerin until a homogeneous slurry was obtained. The
Carbopol 974P was then sifted slowly into the vortex created by the
mixing paddle and allowed to mix until a homogeneous slurry of the
polymer was obtained. Finally, the ammonium hydroxide was added in
a constant, dropwise fashion over a inserted periodically and the
ammonium hydroxide addition proceeded until a pH of exactly 6.50
was obtained. The resulting gel contained 15% by weight hydrogen
peroxide, was highly transparent and had a thixotropic rheological
properties (was non-slumping on a vertical surface). The viscosity
of the resulting gel was 450,000 centipoise, as measured with a
Brookfield RVT viscometer at 25 degrees C., spindle #5, and 0.5
rpm.
[0144] Each of 10 stained bovine enamel slabs was coated with a 1-2
mm thick film of the composition above for 20 minute periods and
exposed during that time to actinic radiation from the inventive
LED array apparatus. Table 7 below shows the results obtained by
exposing gel-treated bovine enamel slabs to the LED array apparatus
at a distance of approximately 1.75 inches from the surface of the
array. This distance corresponded to a power density of
approximately 130 mW/cm.sup.2, which was confirmed using an Ophir
Nova power meter connected to a 30A-SH thermopile detector. A
separate group of 10 bovine enamel slabs was also coated with a 1-2
mm thick film of the same composition, but in this case not exposed
to light in order to demonstrate the effect of the light in
catalyzing the stain removing abilty of the gel. Those results are
also listed in Table 7 below: TABLE-US-00010 TABLE 7 Total Gel
Power Bovine Contact Time Density Corrected Tooth # Light (minutes)
(mW/cm.sup.2) Delta E Delta E* B361 NO 20 0 22.24 22.24 B311 NO 20
0 23.03 23.03 B354 NO 20 0 17.01 16.97 B147 NO 20 0 27.33 27.33 B85
NO 20 0 19.24 18.99 B211 NO 20 0 15.96 15.54 B419 NO 20 0 17.79
15.97 B249 NO 20 0 23.66 23.14 B345 NO 20 0 21.10 21.10 B114 NO 20
0 18.72 18.72 AVG = 20.30 SD = 3.74 B248 YES 20 130 37.62 37.62
B111 YES 20 130 43.20 43.20 B283 YES 20 130 36.57 36.57 B200 YES 20
130 36.92 36.92 B420 YES 20 130 35.95 35.95 B317 YES 20 130 36.13
36.13 B399 YES 20 130 30.28 30.28 B368 YES 20 130 34.06 34.06 B270
YES 20 130 40.54 40.54 B277 YES 20 130 37.19 37.19 AVG = 36.85 SD =
3.45 *Elimination of positive .DELTA.a and .DELTA.b values from
calculation
[0145] The data in Table 1 demonstrates that:
[0146] (1) In the in vitro model described, exposure of bovine
enamel slabs, contacted with the inventive gel composition above,
to actinic radiation from an LED array light source resulted in
significantly (p<0.001) reduced tooth stain as compared to slabs
treated with just gel alone (and not exposed to the light
source).
[0147] Upon reading the subject application, various alternative
constructions and embodiments will become obvious to those skilled
in the art. These variations are to be considered within the scope
and spirit of the subject invention. The subject invention is only
to be limited by the claims which follow and their equivalents.
* * * * *