U.S. patent application number 14/554451 was filed with the patent office on 2015-06-04 for systems and method for protection of optical system of laser-based apparatus.
The applicant listed for this patent is Convergent Dental, Inc.. Invention is credited to Charles H. Dresser, Nathan P. Monty.
Application Number | 20150150649 14/554451 |
Document ID | / |
Family ID | 52130837 |
Filed Date | 2015-06-04 |
United States Patent
Application |
20150150649 |
Kind Code |
A1 |
Dresser; Charles H. ; et
al. |
June 4, 2015 |
SYSTEMS AND METHOD FOR PROTECTION OF OPTICAL SYSTEM OF LASER-BASED
APPARATUS
Abstract
In an apparatus for directing a laser beam to a dental treatment
area, where the apparatus includes a hand piece having an optical
subsystem including a turning mirror for directing a laser beam to
a treatment area via an orifice of the hand piece, a fluid supply
subsystem creates a fluid flow within the hand piece proximate the
turning mirror so as to mitigate contamination thereof.
Inventors: |
Dresser; Charles H.;
(Bethel, ME) ; Monty; Nathan P.; (Shrewsbury,
MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Convergent Dental, Inc. |
Natick |
MA |
US |
|
|
Family ID: |
52130837 |
Appl. No.: |
14/554451 |
Filed: |
November 26, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61909896 |
Nov 27, 2013 |
|
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Current U.S.
Class: |
433/31 ;
433/215 |
Current CPC
Class: |
A61C 1/0046 20130101;
A61C 19/002 20130101; A61B 2018/0097 20130101; A61C 1/0061
20130101; A61B 2018/20359 20170501; A61C 1/0084 20130101 |
International
Class: |
A61C 1/00 20060101
A61C001/00; A61C 19/00 20060101 A61C019/00 |
Claims
1. An apparatus for directing a laser beam to a dental treatment
area, the apparatus comprising: a hand piece comprising an optical
subsystem including a turning mirror for directing a laser beam to
a treatment area via an orifice of the hand piece; and a fluid
supply subsystem for creating a fluid flow within the hand piece,
proximate the turning mirror so as to mitigate contamination of the
turning mirror.
2. The apparatus of claim 1, wherein the hand piece comprises at
least a portion of the fluid supply subsystem.
3. The apparatus of claim 1, wherein the fluid supply subsystem
comprises a conduit and a nozzle for directing a pressurized flow
of a fluid directly toward the turning mirror.
4. The apparatus of claim 1, wherein the fluid supply subsystem
comprises a conduit and a nozzle for directing a pressurized flow
of a fluid transversely across the turning mirror.
5. The apparatus of claim 1, wherein the fluid supply subsystem is
disposed upstream of the turning mirror.
6. The apparatus of claim 1, wherein the fluid supply subsystem is
adapted to pressurize an internal cavity of the hand piece.
7. The apparatus of claim 1, wherein the fluid supply subsystem is
further adapted to direct an air curtain across the orifice of the
hand piece.
8. The apparatus of claim 1, wherein the optical subsystem is
further characterized by an absence of an optical element
downstream of the turning mirror.
9. The apparatus of claim 1, wherein the fluid comprises air.
10. The apparatus of claim 1, wherein the fluid comprises a gas and
a liquid.
11. The apparatus of claim 1, further comprising a radio frequency
(RF) excited CO.sub.2 laser filled with gas at a pressure in a
range of about 260 to 600 Torr, for generating the laser beam.
12. A method of protecting during treatment an optical subsystem of
a treatment system, the method comprising: directing a laser beam
to a treatment area via a hand piece comprising a turning mirror
that is positioned to direct the laser beam to the treatment area
through an orifice of the hand piece; and generating, using a fluid
supply subsystem, a fluid flow within the hand piece and proximate
the turning mirror, so as to mitigate contamination of the turning
mirror.
13. The method of claim 12, wherein the hand piece comprises at
least a portion of the fluid supply subsystem.
14. The method of claim 12, wherein: the fluid supply subsystem
comprises a conduit and a nozzle; and generating the fluid flow
comprises directing a pressurized flow of a fluid through the
nozzle directly toward the turning mirror.
15. The method of claim 12, wherein: the fluid supply subsystem
comprises a conduit and a nozzle; and generating the fluid flow
comprises directing a pressurized flow of a fluid through the
nozzle transversely across the turning mirror.
16. The method of claim 12, wherein the fluid supply subsystem is
disposed upstream of the turning mirror.
17. The method of claim 12, wherein generating the fluid flow
comprises pressurizing an internal cavity of the hand piece.
18. The method of claim 12, further comprising directing an air
curtain across the orifice of the hand piece using the fluid supply
subsystem.
19. The method of claim 12, wherein the optical subsystem is
further characterized by an absence of an optical element
downstream of the turning mirror.
20. The method of claim 12, wherein the fluid comprises air.
21. The method of claim 12, wherein the fluid comprises a gas and a
liquid.
22. The method of claim 1, further comprising generating the laser
beam using a radio frequency (RF) excited CO.sub.2 laser filled
with gas at a pressure in a range of about 260 to 600 Torr.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit of priority to U.S.
Provisional Patent Application No. 61/909,896, entitled "Dental
Laser with Optical System Protection," filed on Nov. 27, 2013, the
contents of which are incorporated herein by reference in their
entirety.
FIELD OF THE INVENTION
[0002] The present disclosure generally relates to a dental laser
hand piece for use with a dental laser ablation system and, in
particular, to systems for cleansing optical components located in
the hand piece.
BACKGROUND OF THE INVENTION
[0003] FIG. 1 shows a cross-sectional view of a hand piece 10, used
for dental laser treatment, such as that described in U.S. Patent
Application Publication No. 2013/0059264 entitled Laser Based
Computer Controlled Dental Preparation System, the contents of
which are incorporated herein by reference in their entirety. The
hand piece 10 includes an optical subsystem that includes a
reflector 12, and the hand piece 10 has an orifice 14 through which
a laser beam can exit. In particular, the reflector 12 can reflect
the laser beam incident from a first optical axis 16 to a second
optical axis 18, and can direct the laser beam through the orifice
14. The optical subsystem may include additional similar or
different optical elements that are located inside the hand piece
10. For example, the optical subsystem may include one or more
lenses for focusing the laser beam, one or more mirrors, one or
more beam splitters, etc.
[0004] Treatment of dental hard tissue using a laser beam, which
typically causes ablation of the tissue, can result in the
formation of debris. A plasma plume may also form during ablative
laser treatment of hard tissue. Often, such debris may be ejected
adjacent to the plasma plume at high speeds and high
temperatures.
[0005] During treatment, the orifice 14 of the hand piece is
generally disposed parallel and open to a treatment area, placing
the reflector 12 in close proximity to the treatment area. For
example, the reflector 12 can be within 0.5-2 inches (or about 1-5
cm), or up to 3 inches (or about 7 cm) from the surface of the
tissue to be treated. As such, contaminants such as debris, water,
and other substances that may form in or around the mouth during
treatment may enter the hand piece 10 through the orifice 14 or
through other openings. Such debris can settle on one or more
components of the optical subsystem and may reduce the efficiency
thereof, and may even render the optical subsystem non-functional.
Frequently removing the optical subsystem from the hand piece 12
and replacing the optical subsystem after cleaning it, or
installing a new subsystem, can be cumbersome and costly, if not
impossible.
SUMMARY OF THE INVENTION
[0006] Various embodiments described herein feature systems and
methods that avoid, or at least reduce, contamination of an optical
subsystem mounted or disposed inside a hand piece from debris
generated during laser-based treatment provided using the hand
piece. This is achieved, at least in part, using a fluid supply
subsystem to create a fluid flow within the hand piece and
proximate a turning mirror included in an optical subsystem
disposed in the hand piece. During treatment, if any debris reaches
inside the hand piece the flow of the fluid (e.g., air) can prevent
such debris, or at least reduce the amount thereof, from attaching
to any components of the optical subsystem including the turning
mirror. Alternatively, or in addition, the fluid flow can cause any
debris attached to the components of the optical subsystem to be
blown away. This can avoid or reduce contamination of the optical
subsystem, and greatly reduce the frequency at which the optical
subsystem including the turning mirror needs to be removed from the
hand piece for cleansing.
[0007] Accordingly, in to one aspect, an apparatus for directing a
laser beam to a dental treatment area includes a hand piece having
an optical subsystem for directing a laser beam to a treatment area
via an orifice of the hand piece. The optical subsystem includes a
turning mirror. The apparatus also includes a fluid supply
subsystem for creating a fluid flow within the hand piece,
proximate the turning mirror so as to mitigate contamination of the
turning mirror. Mitigation of contamination can be indicated by
maintenance of reflectivity resulting in an increase in the lasing
time, which is typically the total time for which the mirror
receives and reflects laser radiation with sufficient reflectivity,
e.g., at least 40%, or 50%, or 60%, or 75% reflectivity, so that
transmission of the laser beam to a treatment area is not
significantly adversely affected and cleansing and/or replacement
of the mirror is not necessary.
[0008] The hand piece may include at least a portion of the fluid
supply subsystem, e.g. one or more conduits and/or one or more
nozzles. In some embodiments, the fluid supply subsystem includes a
conduit and a nozzle for directing a pressurized flow of a fluid
directly toward the turning mirror. Alternatively or in addition,
the fluid supply subsystem may include a conduit and a nozzle for
directing a pressurized flow of a fluid transversely across the
conduit. In some embodiments the fluid is or includes air, while in
other embodiments the fluid includes one or more gas and/or a
liquid. A cleansing agent such as soap may be added to the
fluid.
[0009] In certain embodiments, the fluid supply subsystem or at
least a portion thereof (e.g., a compressor, one or more conduits,
and/or one or more nozzles) is located upstream of the turning
mirror. The fluid supply subsystem may be adapted to pressurize an
internal cavity of the hand piece. The fluid supply subsystem may
be adapted to direct an air curtain across the orifice of the hand
piece. The optical subsystem may be configured such that no optical
element (e.g., a mirror, a lens, etc.) is positioned downstream of
the turning mirror. In some embodiments, the apparatus also
includes a radio frequency (RF) excited CO2 laser filled with gas
at a pressure in a range of about 260 to 600 Torr, for generating
the laser beam.
[0010] In another aspect, a method of protecting during treatment
an optical subsystem of a laser-based treatment system includes
directing a laser beam to a treatment area via a hand piece. The
hand piece includes a turning mirror that is positioned to direct
the laser beam to the treatment area through an orifice of the hand
piece. The hand piece may optionally include other optical elements
such as mirrors, lenses, beam splitters, etc. The method also
includes generating, using a fluid supply subsystem, a fluid flow
within the hand piece and proximate the turning mirror, so as to
mitigate contamination of the turning mirror.
[0011] The hand piece may include at least a portion of the fluid
supply subsystem, e.g., one or more conduits and/or one or more
nozzles. In some embodiments, the fluid supply subsystem includes a
conduit and a nozzle, and generating the fluid flow may include
directing a pressurized flow of a fluid through the nozzle directly
toward the turning mirror. Alternatively or in addition generating
the fluid flow may include directing a pressurized flow of a fluid
through the nozzle transversely across the turning mirror. The
fluid may include only air or may include one or more gases, one or
more liquids and/or one or more additives such as soap.
[0012] In some embodiments, the fluid supply subsystem is disposed
upstream of the turning mirror. Generating the fluid flow may
include pressurizing an internal cavity of the hand piece. The
method may additionally include directing an air curtain across the
orifice of the hand piece using the fluid supply subsystem. In some
embodiments, the optical subsystem is configured such that no
optical element is disposed downstream of the turning mirror. In
some embodiments, the method includes generating the laser beam
using a radio frequency (RF) excited CO.sub.2 laser filled with gas
at a pressure in a range of about 260 to 600 Torr.
BRIEF DESCRIPTION OF THE FIGURES
[0013] Various features and advantages of the present invention, as
well as the invention itself, can be more fully understood from the
following description of the various embodiments, when read
together with the accompanying drawings, in which:
[0014] FIG. 1 depicts a cross-section of a hand piece that includes
a turning mirror;
[0015] FIGS. 2 and 3 depict a cross-section of a hand piece that
includes a turning mirror, and a nozzle for directing a fluid flow
so as to prevent or at least reduce fouling of the turning mirror,
according to different embodiments;
[0016] FIG. 4A depicts a cross-section of a hand piece that
includes a turning mirror, a nozzle for directing a fluid flow so
as to prevent or at least reduce fouling of the turning mirror, and
a nozzle for an air curtain, according to one embodiment; and
[0017] FIG. 4B depicts a cross-section of a hand piece that
includes a turning mirror, a nozzle for directing a fluid flow so
as to prevent or at least reduce fouling of the turning mirror, and
a nozzle for a coolant, according to one embodiment.
DETAILED DESCRIPTION
[0018] With reference to FIG. 2, a fluid supply subsystem 20
includes one or more conduits, such as tubes 22, and one or more
nozzles 24. For example, the fluid supply subsystem 20 can provide
a positive pressure within the hand piece 10, creating a high
pressure cavity 26 therein. Due to a high pressure in the cavity
26, fluid (e.g., air) may flow substantially continuously within
the hand piece 10 and out of the orifice 14. The fluid flow can
impart forces opposing any contaminants ejected into the hand piece
10 through the orifice 14, or otherwise directed toward the
reflector (e.g., a turning mirror) 12. The fluid flow out of the
orifice is generally a function of fluid pressure and size of the
orifice. For an exemplary orifice that is about 2.5 mm in diameter,
a fluid pressure in the cavity 26 in a range from about 10 psi up
to about 100 psi can significantly minimize the amount of debris
attaching and/or remaining attached to the reflector 12. For
example, without the fluid pressure a turning mirror of a diameter
of about 5 mm can become sufficiently contaminated so as to prevent
effective treatment in about one minute of usage. In some
embodiments, the diameter of the mirror can be smaller, e.g., about
2 mm and in other embodiments the diameter can be larger, e.g.,
about 7 mm, 10 mm, etc. Mirrors of non-circular shapes of
comparable area may be used in some embodiments. With the pressure
in the cavity, the rate of contamination can be reduced such that
the turning mirror can reflect and redirect the laser beam, without
having to be removed from the hand piece 10 and cleansed, from at
least two minutes up to about 20 minutes of lasing time, e.g., the
total time for which the mirror receives and reflects laser
radiation with sufficient reflectivity, e.g., at least 40%, or 50%,
or 60%, or 75% reflectivity, so that transmission of the laser beam
to a treatment area is not significantly adversely affected and
cleansing and/or replacement of the mirror is not necessary.
Pressure is generated in a range from about 10 psi up to about 100
psi. Such a flow can be created using fluid compressed using a
commercially available air compressor (e.g., Gardner Denver Thomas
415ZC36/24) and regulator (e.g., SMC NARM1000-2A1-NOIG).
[0019] With reference to FIG. 3, a pressurized fluid flow within
the hand piece 10 is directed transversely over or across the
reflector (e.g., turning mirror) 12 using the nozzle 32. The
pressurized fluid flow can impart forces upon contaminants that are
on or near the surface of the reflector 12, preventing at least
some contaminants from adhering to a surface of the reflector 12
and/or removing at least some contaminants attached thereto. After
the laser beam is reflected by the reflector or turning mirror 12,
no other optical component such as another mirror, a lens, a beam
splitter, etc., interferes with or affects the laser beam, and the
laser beam may directly impinge upon the targeted treatment
area.
[0020] An exemplary pressure supplied to the nozzle 32 is about 55
psi for a typical nozzle size of about 1 mm in diameter. Air or
pure nitrogen may be supplied to the nozzle 32 to create the
transverse fluid flow. In some embodiments, the fluid may include
steam; a combination of two more gases; and a combination of a gas
and a liquid, such as water, soap water, a diluted weak acid/base,
a diluted solvent, etc. The transverse fluid flow can also decrease
the rate of contamination of the turning mirror or reflector 12, as
described above.
[0021] With reference to FIGS. 4A and 4B, a pressurized fluid flow
is generated within the hand piece 10 and is directed toward a
surface of the reflector (e.g., turning mirror) 12 using one or
more nozzles 42. The fluid may include a gas, such as air,
nitrogen, or steam; a combination of two more gases; and a
combination of a gas and a liquid, such as water, soap water, a
diluted weak acid/base, a diluted solvent, etc. The pressurized
flow of both the liquid and the gas may provide for removal of
contaminants from the optical subsystem, as well as cleaning or
rinsing of the optical subsystem components. A nozzle 52 receiving
an air supply from the fluid supply subsystem can form an air
curtain transversely across the orifice 14, minimizing the
likelihood of any debris entering into the hand piece 10.
Alternatively, or in addition, a nozzle 54 receiving one or more
fluids form the fluid supply subsystem can deliver a coolant such a
mist to the treatment area.
[0022] During a typical dental treatment procedure, a pulsed laser
beam may be generated and directed to a dental treatment area via
the hand piece 10. If the fluid flow according to various
embodiments described above includes one or more gases only, the
fluid flow can be maintained continuously ON during the course of
the treatment because the gas flow is not likely to interfere with
the laser beam. If the fluid flow includes a liquid and/or an
additive such as soap, the fluid flow can interfere with the laser
beam by absorbing at least some of the laser energy. Therefore, to
minimize such interference, the fluid flow or at least the flow of
liquid and/or additives may be switched OFF during a burst of
pulses and may be turned ON when substantially no laser pulses are
delivered during a period between two consecutive laser pulse
bursts.
[0023] Laser radiation at wavelengths in a range from about 9.3
.mu.m up to about 9.6 .mu.m can be effective in various dental
and/or surgical procedures including cutting of hard dental tissue
and/or a bone. To generate efficiently laser radiation at these
wavelengths, in the form of pulses having widths in a range from
about 1 .mu.s up to about 30 .mu.s, or up to about 100 .mu.s, or up
to about 250 .mu.s, or even up to about 500 .mu.s, a radio
frequency (RF) excited CO.sub.2 laser operated using gas at a
pressure in a range of about 260 Torr to about 600 Torr may be
used. Such a laser is described in U.S. Patent Application Pub. No.
2011-0189628A1, the contents of which are incorporated herein by
reference in their entirety. Various pulse delivery patterns of the
laser beam, which include a sequence of bursts of laser pulses, are
described in co-pending U.S. patent application Ser. No.
14/172,562, entitled "Dental Laser Apparatus and Method of Use with
Interchangeable Hand Piece and Variable Foot Pedal," filed on Feb.
4, 2014, the entire contents of which are incorporated herein by
reference in their entirety.
[0024] The peak reflectivity of the mirrors used in various
embodiments in the mid to far infrared (e.g., 8-12 .mu.m) range can
be at least 90%. During operation, the reflectivity may decrease
down to about 50%, e.g., due to contamination, when the reduced
reflectivity can interfere with the delivery of the laser beam and
cleansing or replacement of the mirror may be needed. Directing a
fluid flow in proximity of the mirror according to various
embodiments described herein can maintain a reflectivity of at
least 75% during a typical dental treatment session. As such, the
lasing time of the mirror can be increased from about 1 minute
without employing such a fluid flow up to about 2 minutes, 5
minutes, 10, minutes, and even up to about 20 minutes, within a
tolerance of e.g. 1 s, 5 s, 10 s, 30 s, etc., by employing the
fluid flows described in various embodiments.
[0025] Having described herein illustrative embodiments of the
present invention, persons of ordinary skill in the art will
appreciate various other features and advantages of the invention
apart from those specifically described above. It should therefore
be understood that the foregoing is only illustrative of the
principles of the invention, and that various modifications and
additions can be made by those skilled in the art without departing
from the spirit and scope of the invention. Accordingly, the
appended claims shall not be limited by the particular features
that have been shown and described, but shall be construed also to
cover any obvious modifications and equivalents thereof
* * * * *