U.S. patent application number 11/395387 was filed with the patent office on 2007-01-25 for light curing system and method.
Invention is credited to Andrew Lichkus, Scott Shaffer, Benjamin Jiemin Sun.
Application Number | 20070018346 11/395387 |
Document ID | / |
Family ID | 38441830 |
Filed Date | 2007-01-25 |
United States Patent
Application |
20070018346 |
Kind Code |
A1 |
Sun; Benjamin Jiemin ; et
al. |
January 25, 2007 |
Light curing system and method
Abstract
A method for light-curing polymerizable materials to form a
dental device is provided. A light-curing apparatus having at least
one integrated lighting and heating source, a curing volume, and a
temperature controller, preferably a fan, is used in the method.
The light source and temperature controller are used to heat a
first polymerizable material to temperatures within a first
temperature range. A second polymerizable material is applied on or
adjacent to the first polymerizable material. The light source and
temperature controller are used to heat the second polymerizable
material to temperatures within a second temperature range. The
first temperature range has a first midpoint and the second
temperature range has a second midpoint. The first midpoint
temperature is at least 10.degree. C. apart from the second
midpoint temperature. The system is particularly suitable for
making dental devices such as full dentures, removable partial
dentures, relines of full and partial dentures, nightguards, and
occlusal splints.
Inventors: |
Sun; Benjamin Jiemin; (York,
PA) ; Lichkus; Andrew; (York, PA) ; Shaffer;
Scott; (Jacobus, PA) |
Correspondence
Address: |
DENTSPLY INTERNATIONAL INC
570 WEST COLLEGE AVENUE
YORK
PA
17404
US
|
Family ID: |
38441830 |
Appl. No.: |
11/395387 |
Filed: |
March 31, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10106741 |
Mar 26, 2002 |
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11395387 |
Mar 31, 2006 |
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10103741 |
Mar 25, 2002 |
6676294 |
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10106741 |
Mar 26, 2002 |
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09682440 |
Sep 4, 2001 |
6592369 |
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10103741 |
Mar 25, 2002 |
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09670364 |
Sep 26, 2000 |
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09682440 |
Sep 4, 2001 |
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60237523 |
Oct 4, 2000 |
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Current U.S.
Class: |
264/16 |
Current CPC
Class: |
A61C 13/0003 20130101;
A61C 19/003 20130101 |
Class at
Publication: |
264/016 |
International
Class: |
A61C 13/00 20060101
A61C013/00 |
Claims
1. A method for light-curing polymerizable materials to form a
dental device, comprising the steps of: providing a light-curing
apparatus having a least one light source, a curing volume, and a
temperature controller; positioning a first polymerizable material
within said curing volume; controlling said light source and
temperature controller to heat said first polymerizable material to
a temperature within a first temperature range; maintaining said
first polymerizable material at a temperature within said first
temperature range for at least one minute; positioning a second
polymerizable material on or adjacent to said first polymerizable
material within said curing volume; controlling said light source
and temperature controller to heat said second polymerizable
material to temperatures within a second temperature range; and
maintaining said second polymerizable material at a temperature
within said second temperature range for at least one minute, said
first temperature range having a first midpoint and second
temperature range having a second midpoint, said first midpoint
temperature being at least 10.degree. C. apart from said second
midpoint temperature.
2. The method of claim 1, wherein said first temperature range is
within 5.degree. C. of said first midpoint temperature and said
second temperature range is within 5.degree. C. of said second
midpoint temperature.
3. The method of claim 1, wherein said first midpoint temperature
of said first temperature range is at least 15.degree. C. from said
second midpoint temperature of said second temperature range.
4. The method of claim 1, wherein said first temperature range has
a midpoint temperature between 100.degree. C. and 110.degree.
C.
5. The method of claim 1, wherein said first temperature range has
a midpoint temperature between 120.degree. C. and 150.degree.
C.
6. The method of claim 1, wherein the second polymerizable material
is a wax-like polymerizable material.
7. The method of claim 1, wherein the dental device is selected
from the group consisting of full dentures, partial dentures,
denture relines, nightguards, and occlusal splints.
8. The method of claim 7, wherein the dental device is a full
denture.
9. The method of claim 7, wherein the dental device is a partial
denture.
10. The method of claim 1, wherein the light-curing apparatus
further comprises a processor, said processor being connected by an
electrical conductor to said light source.
11. The method of claim 1, wherein the light-curing apparatus
further comprises a processor, said processor being connected by an
electrical conductor to said temperature controller.
12. The method of claim 11, wherein the temperature controller
comprises at least one fan.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 10/106,741 filed Mar. 26, 2002, which is a
continuation-in-part of U.S. patent application Ser. No. 09/682,440
filed Sep. 4, 2001, now U.S. Pat. No. 6,592,369, which is a
continuation-in-part of U.S. patent application Ser. No. 09/670,364
filed Sep. 26, 2000, now abandoned, further claiming the benefit of
U.S. Provisional Patent Application Ser. No. 60/237,523 filed Oct.
4, 2000. The disclosures of the foregoing applications are
incorporated herein by reference in their entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates generally to a light-curing system and
method. More specifically, the system provides controlled heating
of at least two different polymerizable materials within a chamber
at two different temperatures. A single source provides the
necessary curing light and heat to achieve polymerization of both
materials. The first polymerizable material is heated to
temperatures within a first temperature range, and the second
polymerizable material is heated to temperatures within a second
temperature range. The system is particularly suitable for making
dental devices such as full dentures, removable partial dentures,
relines of full and partial dentures, nightguards, occlusal
splints, and the like.
[0004] 2. Brief Description of the Related Art
[0005] Various light-curing systems are known in the dental arts
for making dental products. For example, Masuhara et al., U.S. Pat.
No. 5,135,686 ("the '686 Patent") discloses a method for curing
light-polymerizable objects by placing the objects on a conveyor
belt, which transports the objects through a curing apparatus. The
object is conveyed to a first station, where it irradiated with
visible light from a first source having relatively low radiation
intensity. Moving forward, the object enters a second station,
where it is irradiated with visible light from a second light
source having relatively high radiation intensity. The objective of
the method in the '686 Patent is to control the rate of
polymerization so that the object can be fully and uniformly cured.
The flux density of the irradiating light needs to be controlled in
order that the object does not cure too quickly according to the
'686 Patent. In one embodiment, a mixture of light-curing resins
was placed in a mold and a tooth specimen was embedded in the
resin--the resulting object was placed on a conveyor belt. A first
light source irradiated the object with visible light having low
intensity. Then, a second light source irradiated the object with
high intensity, and the object was polymerized. No cracks were
observed in the polymerized object upon removing it from the mold.
Thus, in the '686 Patent, multiple light sources having different
intensities are used to irradiate the article. The intensity of the
irradiated light varies depending upon the position of the
article.
[0006] Feurstein et al., U.S. Pat. No. 5,922,605 ("the '605
Patent") discloses a polymerization apparatus for light-curing
objects including dental workpieces. The '605 Patent recognizes
that the time for light-curing an object can be shortened when the
object is also heated. Thus, the '605 Patent describes a process,
whereby an object is placed in an apparatus, and a light source is
switched on. The light source begins to polymerize the object.
After the object has been irradiated with the light for a period of
time, for example, 10 minutes, a separate and independent heat
source is switched on. Heating takes place for another 10 minutes
or other suitable time period. Then, the heating and light sources
are switched off, and the object is cooled to end the
polymerization cycle. Thus, in the '605 Patent, the heat source is
used to heat the article sufficiently so that the time for curing
the article is reduced.
[0007] Although the foregoing light-curing systems might be
somewhat effective, it would be especially desirable to have a
system, whereby an integrated lighting and heating source could be
used to polymerize and cure the article. In such a system, one
lighting source for irradiating the article with light and a second
heating source for treating the article with heat would not be
needed. Rather, the same single source would provide sufficient
light and heat to polymerize the article. A system that used a
single source to provide curing light and heat would be
advantageous for several reasons. In such a system, the heat
generated from the light source could be used to internally melt
articles having a partial crystalline structure. At the same time,
the light generated by the lighting source would initiate
polymerization of the article. The heat would be controlled so that
the article did not substantially lose its mechanical integrity or
original shape, while the article was polymerized. The light would
be controlled so that the article could be uniformly and fully
polymerized. A system that produces a polymerized and cured article
according to the following steps would be particularly desirable. A
first polymerizable material would be light-cured using a lighting
and heating source having a temperature within a first temperature
range. Then, a second polymerizable material would be positioned on
or adjacent to the first polymerized material, and the second
material would be light-cured using a lighting and heating source
having a temperature within a second temperature range. In such a
system, the light and heat should be controlled so that the
materials do not substantially change their shapes while ensuring
that the materials are polymerized fully. The material must be
hardened sufficiently so that it has sufficient mechanical
integrity and strength. Such a system could be used advantageously
to produce full and partial dentures and other dental devices. The
present invention provides such a system.
SUMMARY OF THE INVENTION
[0008] The invention provides a light-curing method including the
steps of: providing a light-curing apparatus having at least one
integrated lighting and heating source and a curing volume. The
light-curing apparatus also includes a temperature controller,
which is preferably a fan. A first polymerizable material is
positioned within the curing volume. The light source and
temperature controller are controlled to heat the first
polymerizable material to temperatures within a first temperature
range. The light source and temperature controller are controlled
to maintain the first polymerizable material at temperatures within
the first temperature range for at least one (1) minute so that the
first material is at least partially polymerized. A second
polymerizable material is applied on or adjacent to the first
polymerizable material within the curing volume. The light source
and temperature controller are controlled to heat the second
polymerizable material to temperatures within a second temperature
range. The light source and temperature controller are controlled
to maintain the second polymerizable shaped material at
temperatures within the second temperature range for at least one
(1) minute. The first temperature range has a first midpoint and
the second temperature range has a second midpoint. The first
midpoint temperature is at least 10.degree. C. apart from the
second midpoint temperature. The system is particularly suitable
for making dental devices such as full dentures, removable partial
dentures, relines of full and partial dentures, nightguards,
occlusal splints, and the like.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 shows a schematic diagram of a light-curing apparatus
used for carrying out the method of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0010] The invention is now described with more particular
reference to FIG. 1, which shows a light-curing apparatus (10) for
use in carrying out the method of the invention. Light-curing
apparatus (10) has chamber wall (12) enclosing a curing volume
(14). Shaped, polymerizable material (16) is supported in curing
volume (14) on turntable (18). Processor (20) controls light/heat
source (22) and fan (24) by sending electrical signals through
electrical conductors (26) and (28).
[0011] The invention provides a method for light-curing dental
materials. The method is described herein as being used primarily
to treat two polymerizable dental materials. However, it should be
understood that the method refers to two dental materials for
illustrative purposes only and this should not be considered
restrictive. The method of this invention can be used to cure more
than two polymerizable materials if needed. In FIG. 1, at least two
polymerizable dental materials, independently and collectively
indicated as (16), are placed in a light-curing apparatus (10)
having an integrated lighting and heating source (22) for
transmitting light and heat onto the materials (16). The light and
heat causes the polymerizable materials (16) to be polymerized and
cured. The lighting/heating source (22) preferably includes at
least five incandescent bulbs. The light-curing apparatus further
includes a temperature controller, which is preferably a fan (24).
More preferably, the light-curing apparatus (10) includes at least
one intake fan, at least one exhaust fan and at least one
circulation fan. The rotation of each fan is preferably
independently controlled by the processor (20).
[0012] The intensity of light from the lighting/heating source
(22), which is irradiated onto the first polymerizable material
(16), and rate of rotation of each fan (24) are controlled to heat
the first material (16) to temperatures within a first temperature
range. Then, the lighting/heating source (22) and fan (24) are
controlled to maintain the first polymerizable material (16) at
temperatures within the first temperature range for at least one
(1) minute. In this first light-curing and heating phase, the
material (16) is at least partially polymerized without
substantially losing its original shape.
[0013] Then, a second polymerizable material (16) is positioned on
or adjacent to the first polymerizable material (16), which is at
least partially polymerized at this point, in the curing volume
(14). Before the second polymerizable material (16) is placed in
the curing volume (14), it is preferably heated. For example, the
second polymerizable material (16) may be heated to form a molten
resin, which then may be applied to the first polymerizable
material (16). The intensity of light from the lighting/heating
source (22), which is irradiated onto the second polymerizable
material, and rate of rotation of each fan (24) are controlled to
heat the second material to temperatures within a second
temperature range. Then, the lighting/heating source (22) and fan
(24) are controlled to maintain the second polymerizable material
(16) at temperatures within the second temperature range for at
least one (1) minute. In this second light-curing and heating
phase, the first and second materials (16) are polymerized without
substantially losing their original shapes. Significantly, the
first temperature range has a first midpoint and the second
temperature range has a second midpoint. The first midpoint
temperature is at least 10.degree. C. apart from the second
midpoint temperature. Preferably the first midpoint temperature is
at least 15.degree. C. apart from the second midpoint
temperature.
[0014] As described above, the system of this invention uses a
single lighting/heating source to irradiate the article with curing
light and heat. Suitable lighting/heating sources include, for
example, halogen lamps, xenon lamps, and mercury lamps, provided
that the intensities of the light and heat are in synchronization.
Halogen lamps are preferred, because these lamps are more
economically feasible. The heat generated from the light source
must be sufficient to internally melt materials having a partial
crystalline structure. In the system of the present invention, a
temperature controller, for example, a fan (24) is used to control
the heat's temperature. It is important to prevent excessive
heating of the material; otherwise, the shape and dimensions of the
material will substantially change. Thus, the heat energy is
sufficient to causes a phase change in the material, but the heat
energy is not so great so as to cause substantial deformation of
the material's shape. The heat energy is not used to shorten the
curing cycle as done in prior art systems; rather, it is used to
internally melt the crystalline material. At the same time, the
curing light is controlled so that the material is uniformly and
fully polymerized. That is, the intensities of the light and heat
are synchronized in the system of this invention. The levels of
light energy and heat energy imparted to the material are kept in
balance.
[0015] If there is no synchronization and the heat energy imparted
to the material is much greater than the imparted light energy,
there is excessive heating. This results in the shape of the
material becoming significantly deformed. The geometry and
dimensions of the material are substantially changed. On the other
hand, if the curing light energy imparted to the material is much
greater than the imparted heat energy, there is less internal
melting of the material's crystalline structure. The internal
temperature of the material is not increased sufficiently. And, the
crystalline structure becomes "locked in place." As a result, there
is low polymerization conversion. The material does not fully
polymerized and consequently has low mechanical strength and
integrity. More particularly, it there is excessive heating of the
material during the curing cycle so that the material is heated to
a temperature significantly greater than its glass transition
temperature (Tg), the shape of the material tends to substantially
change. On the other hand, if there is insufficient heating of the
material, so that the material is heated to a temperature
significantly less than its Tg, the material is not hardened
sufficiently. In such a case, the mechanical strength of the
material is weakened. If the material (device) is fixed on a
supporting model, the temperature profile may need to be slightly
above the Tg of the material to achieve improved strength. If the
material (device) is free standing and there is no supporting
model, the temperature profile may need to be slightly below the Tg
of the material for improved shape stability.
[0016] In one embodiment of the invention the first temperature
range is within 5.degree. C. of the first midpoint temperature and
the second temperature range is within 5.degree. C. of the second
midpoint temperature. For example, if the first midpoint
temperature is 95.degree. C., then the first temperature range
extends from 90.degree. to 100.degree. C. A first polymerizable
material (16) is placed on the turntable (18) within the curing
volume (14). In one embodiment, the first polymerizable material is
used to form a baseplate for a denture as described in further
detail below. The first polymerizable material may be a "wax-like"
polymerizable material. By "wax-like" as used herein, it is meant
any material which is flowable (fluid) above 40.degree. C. and
which becomes dimensionally stable (i.e., it solidifies and is
non-fluid) at a temperature of at least and below 23.degree. C.
Flowable wax-like material having a temperature in the range of
40.degree. C. to 100.degree. C. becomes dimensionally stable within
five minutes by cooling it to an ambient temperature in the range
of 0.degree. C. to 23.degree. C. Wax-like polymerizable materials
include, for example, methacrylate (or acrylate) compounds prepared
by reaction of a urethane pre-oligomer with
hydroxylalkylmethacrylate. Such wax-like polymerizable materials
are described in Sun et al., U.S. Pat. No. 6,592,369, the
disclosure of which is incorporated herein by reference. The
lighting/heating source (22) and fan (24) of the light-curing
apparatus (10) are controlled to heat the first polymerizable
material (16) to temperatures within a first temperature range. The
material (16) is maintained at temperatures within the first
temperature range for at least one (1) minute, whereby the material
(16) is partially polymerized without a substantial loss of its
original shape. A preferred first temperature range has a midpoint
temperature in the range of about 60.degree. to 11.degree. C. The
time period of the first curing cycle will vary, but it is
typically within the range of about 2 to about 10 minutes.
[0017] Subsequently, a second polymerizable material can be
positioned on or adjacent to the first polymerizable material,
which has been at least partially polymerized at this point. In one
embodiment, the second polymerizable material is used to line the
outer surface of the baseplate and affix the artificial teeth. The
second polymerizable material can have either the same or different
composition as the first polymerizable material. Preferably, the
second polymerizable material has a different composition. Wax-like
polymerizable materials, as described above, are used preferably as
the second polymerizable material in accordance with this
invention. The lighting/heating source (22) and fan (24) of the
light-curing apparatus (10) are controlled to heat the second
polymerizable material to temperatures within a second temperature
range. The second material is maintained at temperatures within the
second temperature range for at least one (1) minute, whereby the
first and second materials are polymerized. Significantly, the
heating of the first and second polymerizable materials is
controlled during this second heating phase so that the first and
second materials do not have a substantial loss of shape. A
preferred second temperature range has a midpoint temperature in
the range of about 90.degree. to 150.degree. C. The time period of
the second curing cycle will vary, but it is typically within the
range of about 2 to about 10 minutes.
[0018] In a preferred embodiment of the invention the curing zone
or volume (14) in the light-curing apparatus (10) has a diameter of
5 inches and a height of 3 inches. The curing lamp system provides
an intensity of at least 3 mW/cm.sup.2 of light having wavelengths
from 350-500 nm, (more preferably having wavelengths from 350-410
nm) wherein the light is substantially evenly distributed
throughout the curing zone (14). The turntable (18), which holds
the polymerizable material (16) preferably rotates at 3-7
revolutions per minute (rpm). The elevation of the turntable (18)
is adjustable, so that the upper face of the turntable (18), is
movable from the bottom plane of the curing zone (14), which is at
a height of 0 inches, to a raised height of about 2 inches.
[0019] The system is particularly suitable for making dental
devices such as, for example, full dentures, removable partial
dentures, relines of full and partial dentures, nightguards,
occlusal splints, and the like.
[0020] In one preferred embodiment, a full denture is made using
the system and method of this invention. To make the denture, a
dentist first takes an impression of a patient's dental anatomy
using techniques well known in the art. In one customary method, a
paste-like material, such as an alginate, is placed in a standard
or custom-made impression tray. The dentist inserts the tray in the
mouth of the patient, and the patient bites down into the tray.
Separate impression trays for the upper and lower dental arches are
used. The dentist removes the trays from the patient's mouth and
sets them aside. The dentist typically sends the hardened
impressions to a dental laboratory that will produce the denture.
The dental technician, at the laboratory, prepares casts (models)
of the upper and lower arches by pouring dental plaster into the
hardened impressions. The plaster typically contains gypsum. The
resulting plaster model has a shaped surface closely representing
the patient's dental anatomy. In the laboratory, the dental
technician applies a thin, smooth coating of a releasing agent (for
example, silicone or alginate) to the dental model and places the
coated model in a conditioning oven. Heating time and temperature
will vary, but the model is typically heated to a temperature in
the range of 120.degree. to 130.degree. F. (49.degree. to
54.degree. C.) for about 30 minutes.
[0021] The denture base (baseplate) is next prepared by molding a
first polymerizable material over the warm model. The polymerizable
resin is applied so that it fully covers the surface of the model.
The resin is carefully applied to the labial/buccal and
palatal/lingual surfaces on the model so as to avoid air
entrapment. The resin should be applied at a uniform thickness.
Using fingers and modeling instruments, the resin is applied
smoothly to the model. Any excess material is trimmed away using a
knife or other sharp instrument. Then, a thin layer of an air
barrier coating may be applied over the entire surface of the
resin-coated model. The air barrier coating helps to ensure optimum
curing of all surfaces. The resin-coated model then is placed in
the light-curing apparatus described above. Then, the resin-coated
model is irradiated with curing light and heated to a suitable
temperature. In one embodiment of a curing cycle, the temperature
of the light-curing apparatus is room temperature at 0 minutes,
about 75.degree. C. at two minutes, about 100.degree. C. at four
minutes, and about 140.degree. C. at ten minutes.
[0022] When the curing cycle has been completed, the cured
baseplate and supporting model are removed from the light-curing
apparatus. The baseplate/model should be allowed to cool until it
reaches ambient temperature. The cured baseplate is then removed
from the model. To facilitate removal of the baseplate from the
model, the baseplate/model assembly may first be soaked in tap
water for 5 to 15 minutes. Excess material may be trimmed from the
borders of the cured baseplate. The surfaces of the baseplate
should be smooth and even. Then, the dental laboratory technician
applies wax occlusal rims to the baseplate and sends the baseplate
to the dentist so that he can evaluate the fit of the baseplate in
the patient's mouth. The dentist may adjust the wax rims for proper
lip support and make occlusal and aesthetic markings (for example,
smile line) on the wax rims. The dentist then returns the baseplate
to the dental laboratory. The baseplate is mounted on the model and
the occlusal and aesthetic markings from the baseplate are
transferred to the model. While the baseplate is still on the
model, the wax material is cleaned from the baseplate by rinsing
with clean boiling water. After cooling, the outer surface of the
baseplate is roughened-up using a bur or diamond. This will help
improve bonding of the artificial teeth to the outer surface of the
baseplate. Then, the entire surface of the denture baseplate is
cleaned using a cleaning agent such as isopropyl or ethyl/denatured
alcohol and dried with blown air. The artificial teeth are now
ready to be set on the baseplate.
[0023] First, a sheet or rope of a polymerizable material, also
referred to as a set-up resin, is placed onto the outer surface of
the baseplate. The surface of the set-up resin is melted with an
electric spatula or hot air gun just prior to tooth placement. The
teeth are then pressed into the set-up resin while the resin is in
a softened condition. Then, a molten polymerizable material, also
referred to as molten contour resin, which has been prepared
previously by placing the resin in a melting pot set at a high
temperature, for example, at about 189.degree. F., is applied so
that it flows around the embedded artificial teeth. The contour
resin should flow between the embedded teeth smoothly and evenly,
because, once the resin hardened, it will hold the teeth in
position. As the contour resin flows around the embedded teeth, it
covers the set-up resin and any exposed baseplate. The uncured
denture is now ready to be sent to the dentist so that he or she
can place it in a patient's mouth as a "try in." The dental
laboratory sends the uncured denture to the dentist. Due to the
light-curing nature of the materials, the denture is sent in a
light-safe bag.
[0024] The dentist seats the denture in the patient's mouth and
evaluates its fit. This procedure is commonly referred to as a "try
in." It may be necessary to make adjustments to the baseplate and
embedded teeth according to the dental anatomy of the patient. The
denture should be fitted so that it conforms tightly to the
contours of the patient's oral cavity and there is good occlusion.
Since the denture is uncured and has an extended working time, the
dentist can make some minor chairside adjustments. Then, the
denture device is sent back to the dental laboratory so that the
final denture device can be prepared. If needed, the laboratory
technician can reposition the anterior and posterior teeth and make
other major adjustments.
[0025] At the laboratory, the denture is placed back on the model
(a new model may be prepared if needed), and an air barrier coating
is applied so that it covers all external resin surfaces and
embedded teeth. The denture and supporting model are placed in a
conditioning oven and heated at 130.degree. F. for at least one
hour. The denture/model is removed from the conditioning oven and a
model releasing agent is applied to the flange areas of the
denture. In one embodiment, the denture is sealed to the model by
applying a sealing gel to the borders of the denture. Next, the
denture/model is placed in the light-curing apparatus described
above. The denture/model is heated to a suitable temperature and
light-cured. In one embodiment, the temperature of the light-curing
apparatus is about 50.degree. C. at 0 minutes, about 85.degree. C.
at two minutes, about 95.degree. C. at four minutes, and about
105.degree. C. at ten minutes.
[0026] After the light-curing/heating cycle has been completed, the
denture/model is removed and allowed to cool until the denture
reaches ambient temperature. Then, the denture is separated from
the model. The cured sealing gel is removed from the denture and
the air barrier coating is washed away with water and a soft brush.
Finally, the denture is finished and polished using conventional
techniques. Workers skilled in the art will appreciate that various
modifications and additional steps can be made to above-described
method for making denture devices. The foregoing method is provided
for illustration purposes only and should not be considered
restrictive.
[0027] The invention is illustrated by the following examples,
which are not intended to be limiting. Exemplary compositions,
which may be used as the light-curable polymerizable materials, are
described in the following Examples 1-6. Exemplary dental devices,
which may be made from the light-curable polymerizable materials,
are described in the following Examples 7-9.
EXAMPLES
Example 1
Preparation of Oligomer
[0028] A reactor was charged with 1176 grams of
trimethyl-1,6-diisocyanato-hexane (5.59 mol) and 1064 grams of
bisphenol A propoxylate (3.09 mol) under dry nitrogen flow and
heated to about 65.degree. C. under a positive nitrogen pressure.
To this reaction mixture, 10 drops of catalyst dibutyltin dilaurate
were added. The temperature of the reaction mixture was maintained
between 65.degree. C. and 140.degree. C. for about 70 minutes and
followed by additional 10 drops of catalyst dibutyltin dilaurate. A
viscous paste-like isocyanate end-capped intermediate product was
formed and stirred for 100 minutes. To this intermediate product,
662 grams (5.09 mol) of 2-hydroxyethyl methacrylate and 7.0 grams
of BHT as an inhibitor were added over a period of 70 minutes while
the reaction temperature was maintained between 68.degree. C. and
90.degree. C. After about five hours stirring under 70.degree. C.,
the heat was turned off, and oligomer was collected from the
reactor as semi-translucent flexible solid and stored in a dry
atmosphere.
Example 2
Preparation of Monomer
[0029] A reaction flask was charged with 700 grams of
1,6-diisocyanatohexane and heated to about 70.degree. C. under a
positive nitrogen pressure. To this reactor were added 1027 grams
of 2-hydroxyethyl methacrylate, 0.75 gram of catalyst dibutyltin
dilaurate and 4.5 grams of butylated hydroxy toluene (BHT). The
addition was slow and under dry nitrogen flow over a period of two
hours. The temperature of the reaction mixture was maintained
between 70.degree. C. and 90.degree. C. for another two hours and
followed by the addition of 8.5 grams of purified water. One hour
later, the reaction product was discharged as clear liquid into
plastic containers and cooled to form a white solid and stored in a
dry atmosphere.
Example 3
Preparation of Polymerizable Denture Contour Material
[0030] A wax-like polymerizable dental material was prepared by
stirring at 85.degree. C., a liquid mixture of 63.0 grams of
oligomer made the procedure of Example 1 and 37.0 grams of compound
of Example 2, 0.35 gram of 2,4,6-trimethylbenzoyldiphenylphosphine
oxide, (Lucirin TPO made by BASF), 0.5 gram of solution containing
8.3% camphorquinone (CQ), 25% ethyl 4-dimethylaminobenzoate (EDAB)
and 66.7% 1,6-hexanediol dimethacrylate (HDDMA).
Example 4
Preparation of Polymerizable Denture Base Plate (or Reline)
Material
[0031] A light curable polymerizable material was prepared by
stirring at 85.degree. C., a liquid of 98.0 grams of TBDMA oligomer
of Example 1, 0.35 gram of 2,4,6-trimethylbenzoyidiphenylphosphine
oxide, (Lucirin TPO made by BASF), 1.5 gram of solution containing
8.3% camphorquinone (CQ), 25% ethyl 4-dimethylaminobenzoate (EDAB)
and 66.7% 1,6-hexanediol dimethacrylate (HDDMA), 0.1 gram of red
acetate fibers and 0.05 gram of pigment.
Example 5
Preparation of Polymerizable Wax-Like Denture Contour Material
[0032] A light curable wax-like polymerizable dental material was
prepared by stirring at 85.degree. C., a liquid mixture of 50.5
grams of oligomer of Example 1, 45.0 grams of monomer of Example 2,
and 4.0 grams of stearyl acrylate from Sartomer. To this mixture
were added 0.35 gram of 2,4,6-trimethylbenzoyidiphenylphosphine
oxide (Lucirin TPO), 0.1 gram of red acetate fibers and 0.05 gram
of pigment concentrates. The polymerizable wax-like material formed
becomes flowable at 65 to 68.degree. C.
Example 6
Preparation of Polymerizable Denture Set-Up Material
[0033] A light curable polymerizable material was prepared by
stirring at 85.degree. C., a liquid mixture of 84.5 grams of
oligomer of Example 1 and 15.0 grams of monomer of Example 2. To
this mixture, 0.35 gram of 2,4,6-trimethylbenzoyldiphenylphosphine
oxide (Lucirin TPO), 0.1 gram of red acetate fibers and 0.05 gram
of pigment were added.
Example 7
Preparation of a Denture without Forming a Mold Cavity of a Denture
Base
[0034] A plaster cast of a patient's mouth is coated with a release
agent (e.g., Al-Cote.RTM. and Isolant.RTM. sold by Dentsply
International Inc. or Teflon.RTM. solution such as Krytox.RTM. from
DuPont) and heated to 55.degree. C. in an incubator. An arch-shaped
baseplate resin containing 14 grams of the product of Example 4 is
applied and shaped onto the warm cast. The resin is shaped and
flowed to fully cover the cast, using finger pressure and trimming
to form a baseplate. The baseplate is cured for 10 minutes in the
visible light-curing unit. The temperature of the device is at room
temperature at 0 minute, around 75.degree. C. at 2 minutes,
100.degree. C. at 4 minutes, and 140.degree. C. at 10 minutes. A
sufficient quantity of the product of Example 6 is formed into a
rope. The rope is applied to the baseplate. Then artificial teeth
are pressed into the rope with the thickness of the rope adapted to
adequately cover the appropriate surfaces of the teeth to provide
support. Melted product of Example 5 from an 87.degree. C. wax pot
is applied by using an electric spatula between the teeth and the
baseplate to fully embed teeth and to flow into fissures between
teeth and to smooth the outer surface of the denture. Hot air from
a small nozzle hot air gun may also be applied to let the product
of Example 5 flow into fissures between teeth and smooth the outer
surface of the denture. The lingual and buccal surfaces of the
denture are contoured, trimmed and carved using a spatula. The
denture is placed in a patient's mouth for try-in at a dental
office and tooth positions are adjusted. The denture back is fitted
to the cast and the TRIAD Air Barrier Coating is painted on the
denture. The denture is placed into conditioning oven at 55.degree.
C. for at least 1 hour. A model release agent (MRA) sold by
Dentsply International Inc. is applied to around the border of
denture and the cast immediately. A strip of Triad gel is applied
on surface between the border and the cast and cured in a visible
light-curing unit for 10 minutes. The temperature of the device is
50.degree. C. at 0 minutes, around 85.degree. C. at 2 minutes,
95.degree. C. at 4 minutes, and 105.degree. C. at 10 minutes. When
cured, the denture is washed with water to remove all traces of Air
Barrier Coating. The denture is then finished and polished.
Example 8
Preparation of a Partial Denture without Forming a Mold Cavity
(investment) of a Denture Base
[0035] A removable partial denture framework is fabricated. A
separating medium is applied to a gypsum cast of the patient's
dentition. A sufficient quantity of the product of Example 4 is
applied onto the edentulous areas of the cast and adapted with
finger pressure or appropriate instruments. Excess material is
trimmed with a hot spatula. A sufficient quantity of the product of
Example 4 is adapted into the tissue side finish line of the
partial denture framework. The framework is seated on the cast
firmly, embedding the uncured material of Example 4. All rests and
tissue stops are varnished as correctly positioned on the cast,
indicating that the framework is fully seated. Excess material is
removed and these baseplate areas are cured in the visible
light-curing unit. The temperature of the device is at room
temperature at 0 minute, around 50.degree. C. at 2 minutes,
80.degree. C. at 4 minutes and 90.degree. C. at 10 minutes. A rope
of the product of Example 6 is adapted onto the precured
baseplate/edentulous areas. The rope has a thickness sufficient to
cover the ridge lap surfaces of the teeth to provide support for
the teeth and to seat the teeth, which are then set up in the rope.
A portion of the product of Example 5 is applied between the teeth
and the baseplate. A small nozzle hot air gun is used to melt the
product of Example 5 so that it flows into the fissures between
teeth as the outer surface smoothes. The lingual and buccal
surfaces of the edentulous areas are contoured, trimmed and carved
using an electric hot spatula, sharp tools and hot air gun. The
partial denture wax-up is removed from the cast for try-in. The
denture is placed in a patient's mouth for try-in at a dental
office and tooth positions adjusted if needed. The partial denture
is fitted to a modified cast (reduced soft tissue heights of
contour). TRAID Air Barrier Coating is painted onto the denture.
Then a mold release agent (MRA) sold by Dentsply International,
Inc. is applied around the posterior teeth and supporting resin. A
strip of triad gel is applied between teeth and on the surface of
the supporting resin to form a continuous circle. The denture is
then cured in the visible light-curing unit for 10 minutes. The
temperature of the device is at room temperature at 0 minutes,
around 80.degree. C. at 2 minutes, 95.degree. C. at 4 minutes, and
105.degree. C. at 10 minutes. When cured, the partial denture is
washed with water to remove all traces of Air Barrier Coating. The
partial denture is then finished and polished.
Example 9
Preparation Of A Night Guard Without Forming A Mold Cavity Of A
Night Guard
[0036] A plaster cast of a patient's teeth is coated with a release
agent. 20 grams of the product composition of Example 3 is applied
over the release agent and warmed to 50.degree. C. in an oven. The
composition is shaped using finger pressure and trimming to form a
night guard which hardens when cooling to room temperature. The
surfaces of the night guard are contoured, trimmed and carved using
an electric hot spatula and hot air gun. After the night guard is
examined and adjusted to fit articulator, the night guard is fitted
to the cast and a TRAID Air Barrier Coating is painted on the
denture and cured for 10 minutes. The temperature of the device is
at room temperature at 0 minutes, around 95.degree. C. at 2
minutes, 100.degree. C. at 4 minutes, and 110.degree. C. at 10
minutes. The clear night guard is then washed with water to remove
all traces of Air Barrier Coating. The night guard is then finished
and polished.
[0037] It should be understood that while the present invention has
been described in considerable detail with respect to certain
specific embodiments thereof, it should not be considered limited
to such embodiments but may be used in other ways without departure
from the spirit of the invention and the scope of the appended
claims.
* * * * *