U.S. patent application number 12/476918 was filed with the patent office on 2009-09-24 for dental prosthetics comprising curable acrylate polymer compositions and methods of their use.
This patent application is currently assigned to SCIENTIFIC PHARMACEUTICALS, INC. Invention is credited to David V. Butler, Alice Chin, Jan A. Orlowski.
Application Number | 20090239969 12/476918 |
Document ID | / |
Family ID | 34983968 |
Filed Date | 2009-09-24 |
United States Patent
Application |
20090239969 |
Kind Code |
A1 |
Orlowski; Jan A. ; et
al. |
September 24, 2009 |
DENTAL PROSTHETICS COMPRISING CURABLE ACRYLATE POLYMER COMPOSITIONS
AND METHODS OF THEIR USE
Abstract
Disclosed herein are acrylic and methacrylic acid ester-based
polymeric materials containing as flexibilizing and brittleness
reducing agents 1-60% of C.sub.4-C.sub.8 polyalkylene or
polyalkyldiene compounds, preferably having a molecular weight of
300-2100, and the use of such materials in dentistry and
medicine.
Inventors: |
Orlowski; Jan A.; (Altadena,
CA) ; Butler; David V.; (West Covina, CA) ;
Chin; Alice; (Monterey Park, CA) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET, FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Assignee: |
SCIENTIFIC PHARMACEUTICALS,
INC
Pomona
CA
|
Family ID: |
34983968 |
Appl. No.: |
12/476918 |
Filed: |
June 2, 2009 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10914972 |
Aug 10, 2004 |
|
|
|
12476918 |
|
|
|
|
Current U.S.
Class: |
523/116 ;
427/2.29; 433/226; 526/319; 526/324 |
Current CPC
Class: |
A61L 24/046 20130101;
A61K 6/30 20200101; A61C 19/003 20130101; A61K 6/887 20200101; A61K
6/893 20200101; A61K 6/20 20200101; A61K 6/887 20200101; C08L 33/04
20130101; A61K 6/887 20200101; C08L 23/18 20130101; A61K 6/893
20200101; C08L 75/16 20130101; A61K 6/30 20200101; C08L 75/16
20130101; A61K 6/20 20200101; C08L 75/16 20130101; A61K 6/20
20200101; C08L 23/18 20130101; A61K 6/30 20200101; C08L 23/18
20130101; A61K 6/30 20200101; C08L 33/04 20130101; A61K 6/20
20200101; C08L 33/04 20130101; A61K 6/893 20200101; C08L 75/16
20130101; A61K 6/30 20200101; C08L 75/16 20130101; A61K 6/30
20200101; C08L 23/18 20130101; A61K 6/30 20200101; C08L 33/04
20130101; A61K 6/20 20200101; C08L 75/16 20130101; A61K 6/20
20200101; C08L 23/18 20130101; A61K 6/20 20200101; C08L 33/04
20130101; A61K 6/887 20200101; C08L 33/04 20130101; A61K 6/887
20200101; C08L 23/18 20130101 |
Class at
Publication: |
523/116 ;
526/319; 526/324; 427/2.29; 433/226 |
International
Class: |
A61K 6/083 20060101
A61K006/083; C08F 222/10 20060101 C08F222/10; B05D 3/00 20060101
B05D003/00; A61C 5/04 20060101 A61C005/04 |
Claims
1. A method of performing a dental procedure, comprising obtaining
a curable composition comprising: 10-90% by weight of one or more
acrylic monomers; and 1-60% by weight of an olefinic component
comprising oligomers or polymers of one or more straight chain or
branched C.sub.4-C.sub.6 monomers having one or two double bonds
per monomer molecule; applying the composition to at least one
surface of a tooth or dental appliance; and allowing the
composition to cure.
2. The method of claim 1, wherein the allowing the composition to
cure comprises applying heat to the composition.
3. The method of claim 1, wherein the allowing the composition to
cure comprises applying UV or visible light to the composition.
4. The method of claim 1, wherein the curable composition is in two
parts.
5. The method of claim 4, further comprising mixing the two parts
prior to applying.
6. The method of claim 1 wherein the one or more acrylic monomers
are esters of acrylic or methacrylic acid having one to three
acrylate or methacrylate groups per molecule.
7. The method of claim 1, wherein the one or more acrylic monomers
are selected from the group consisting of (C.sub.1-C.sub.4)
alkylene glycol dimethacrylate, diurethane dimethacrylate,
ethoxylated bis-phenol-A dimethacrylate, 2,2-bis[4-(2-hydroxy-
-3-methacryloylpropoxy)phenyl]propane, hydroxyethyl methacrylate,
hydroxypropyl methacrylate, hydroxybutyl methacrylate, and
tetrahydrofurfuryl methacrylate.
8. The method of claim 1, wherein the olefinic component comprises
polybutene, polybutadiene, and/or isoprene.
9. A medical or dental device made from a composition comprising:
10-90% by weight of one or more acrylic monomers; and 1-60% by
weight of an olefinic component comprising oligomers or polymers of
one or more straight chain or branched C.sub.4-C.sub.6 monomers
having one or two double bonds per monomer molecule; wherein said
device is a dental restorative material, prosthesis, cement, cavity
liner, varnish or sealer.
10. The composition of claim 9 wherein the one or more acrylic
monomers are esters of acrylic or methacrylic acid having one to
three acrylate or methacrylate groups per molecule.
11. The composition of claim 9, wherein the one or more acrylic
monomers comprises (C.sub.1-C.sub.4) alkylene glycol
dimethacrylate.
12. The composition of claim 9, wherein the one or more acrylic
monomers comprises diurethane dimethacrylate.
13. The composition of claim 9, wherein the one or more acrylic
monomers comprises ethoxylated bis-phenol-A dimethacrylate.
14. The composition of claim 9, wherein the one or more acrylic
monomers comprises 2,2-bis[4-(2-hydroxy-
-3-methacryloylpropoxy)phenyl]propane.
15. The composition of claim 9, wherein the one or more acrylic
monomers comprises a hydroxy (C.sub.2-C.sub.4) alkyl
methacrylate.
16. The composition of claim 15, wherein the hydroxy
(C.sub.2-C.sub.4) alkyl methacrylate, comprises hydroxyethyl,
hydroxypropyl and/or hydroxybutyl methacrylate.
17. The composition of claim 9, wherein the one or more acrylic
monomers comprises tetrahydrofurfuryl methacrylate.
18. The composition of claim 9, wherein the one or more acrylic
monomers comprises (C.sub.1-C.sub.5) alkyl monomethacrylates.
19. The composition of claim 9, wherein the olefinic component
comprises polybutene.
20. The composition of claim 9 wherein the olefinic component
comprises polybutadiene.
21. The composition of claim 9 wherein the olefinic component
comprises isoprene.
22. The composition of claim 9, wherein the olefinic component has
an average molecular weight of 300-2500 and viscosity of 25-4500 cp
at 23.degree. C.
23. The composition of claim 9 further comprising one or more
additives selected from the group consisting of polymerization
initiators, polymerization activators, stabilizers, UV light
absorbers, colorants, fillers, therapeutic agents, flavoring agents
and viscosity/rheological modifiers.
24. The composition of claim 9 further comprising 1-60% by weight
of one or more inorganic fillers.
25. The composition of claim 24 wherein the inorganic filler
comprises glass, quartz silica, aluminum oxide, zirconium oxide,
barium sulfate or mixtures thereof.
26. The composition of claim 9 wherein the composition is curable
by heat.
27. The composition of claim 9, wherein the composition comprises a
first part comprising a peroxide polymerization activator and a
second part comprising a tertiary aromatic amine polymerization
activator.
28. The composition of claim 27 wherein the polymerization
activator comprises benzoyl peroxide or its halogen substituted
derivatives.
29. The composition of claim 27, wherein the tertiary aromatic
amine comprises N,N bis-(2-hydroxyethyl) p-toluidine or N,N
diethyl-p-toluidine.
30. The composition of claim 27, further comprising camphoroquinone
and tertiary aliphatic amine as light-induced
polymerization-activating additives.
31. The composition of claim 30, wherein the amine is selected from
the group consisting of trialkylamines,
methacroylalkyl-dialkylamines, and combinations thereof.
32. The composition of claim 9 wherein the composition is curable
by light.
Description
RELATED APPLICATION INFORMATION
[0001] This application is a divisional of U.S. patent application
Ser. No. 10/914,972, filed Aug. 10, 2004.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to modified, acrylate polymer
compositions featuring reduced brittleness, such polymers being
particularly suitable as dental/medical cements and restorative
materials and for manufacturing dental prosthetics.
[0004] 2. Description of the Related Art
[0005] Polymeric materials based on the esters of methacrylic acid
have found widespread industrial and medical applications. Their
role is particularly prominent in dentistry where they have become
a base for modern restorative materials, cements, varnishes, cavity
liners and sealers. In medicine perhaps the most important uses of
acrylic resins include contact lenses and cements used for hip
restorations.
[0006] Many of these applications require the material to meet a
combination of requirements with respect to their chemical, optical
and mechanical properties and, frequently, biological
compatibility. While acrylic resins, due to a variety of available
monomers, usually make it possible to compound a blend which, upon
cure, will result in a polymer meeting the requirements of tissue
biocompatibility, wear resistance, translucency, mechanical
strength or hardness, they frequently fail or are less than
satisfactory in applications requiring flexibility. It is
especially true in situations where thin layers of polymers are
exposed to flexural forces; for example, while placing or removing
a well-fitted device. Another example of situations where the
greater flexibility and impact resistance of acrylic polymers would
be highly desirable are applications where the devices made of such
polymeric materials are exposed to rapid or repetitiously applied
forces. Especially vulnerable are thin areas of such objects.
[0007] In applications requiring longevity, mechanical strength and
resistance to exposure to environments which may have a
deteriorating effect on the polymeric material by means of wear,
chemical reaction, exposure to heat, light, etc., cross-linked
acrylic polymers are generally preferred over the linear ones.
Consequently, in addition to monounsaturated monomers frequently
used in such applications, exemplified by alkylmethacrylates,
tetrahydrofurfuryl methacrylate and hydroxyalkyl methacrylates,
di-, tri- or even higher polymethacrylates are employed. Such
polyfunctional monomers may be used in blends with monofunctionals
serving as cross-linking agents, or in compositions where
monofunctional monomers are absent. In applications requiring high
mechanical strength and chemical and wear resistance, in addition
to low polymerization shrinkage and low exotherm of the curing
process, higher molecular weight dimethacrylates are generally the
monomers of choice. Such monomers are particularly useful in
formulating modern self- and light-cured dental restorative
materials, prostheses, cements, cavity liners, varnishes and
sealers. Their use is also expanding in orthopedic surgery, where
they are replacing, or being used as adjuncts to, monomethacrylate
monomers to enhance mechanical properties and chemical resistance
of resulting polymers.
[0008] Acrylic resins have unique features making them difficult to
replace with other types of monomers, especially in particular or
very demanding applications. These include ease of control of
working and curing times, good biocompatibility, and a broad
selection of available monomers, and relative ease of synthesizing
new ones, having desirable molecular structures allows for
modifying or controlling relevant characteristics of cured polymers
such as water absorption, solubility, hydrophobicity, adhesive
properties, compatibility with various additives, optical
properties, mechanical strength, chemical resistance and resistance
to heat and UV light. These properties allow for multiple ways of
inducing polymerization, such as by chemical means, heat, or
light.
[0009] These advantages make acrylic resin unique, important and
often irreplaceable in many applications, especially in a dental
field that has been revolutionized by their advent and consequent
expansion.
SUMMARY OF THE INVENTION
[0010] Compositions according to preferred embodiments, in which
olefinic polymers are used as additives to acrylic polymers,
provide more flexible and impact-resistant acrylate polymers
suitable for a variety of uses, particularly those related to
medical and dental fields. Preferred compositions also effectively
address the reducing or eliminating of the oxygen-inhibited layer
and/or reducing the exothermic effect of the polymerization
process.
[0011] Another advantage of polymers in accordance with preferred
embodiments, particularly important in medical and dental
applications, is their general lack of toxicity as well as a low
incidence or absence of allergenic reaction and tissue
irritation.
[0012] In accordance with preferred embodiments, there is provided
a curable composition comprising about 10-90% by weight of one or
more acrylic monomers; and about 1-60% by weight of an olefinic
component comprising oligomers or polymers of one or more straight
chain or branched C4-C6 monomers having one or two double bonds per
monomer molecule. The compositions may further comprise one or more
additives selected from the group consisting of polymerization
initiators, polymerization activators, stabilizers, UV light
absorbers, colorants, fillers, therapeutic agents, flavoring agents
and viscosity/rheological modifiers. The compositions may exist as
one part or component, or they may be in two parts that are mixed
together prior to use. The composition may be used in medical
and/or dental applications as a medical device such as a
restorative material, prosthesis, cement, cavity liner, varnish or
sealer.
[0013] In accordance with one embodiment, there is provided a
method of performing a dental procedure, comprising obtaining a
curable composition comprising 10-90% by weight of one or more
acrylic monomers and 1-60% by weight of an olefinic component
comprising oligomers or polymers of one or more straight chain or
branched C4-C6 monomers having one or two double bonds per monomer
molecule; applying the composition to at least one surface of a
tooth or dental appliance; and allowing the composition to
cure.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0014] The technology disclosed herein relates to heat, chemically
(i.e. self-curable) or light (UV and/or visible) curable acrylate
acrylic resin-based formulations as well as polymers or objects
resulting from curing of such formulations.
[0015] Although acrylic resins have the numerous possible
advantages noted above, certain intrinsic characteristics of
acrylic resins have limited their scope of application or have
complicated their handling or reliability. Such characteristics
include brittleness of cured polymers, oxygen-inhibited thin liquid
layer remaining on the surface of the cured polymer that leaves a
dull surface after being wiped off, and high exothermicity
accompanying the polymerization process. Although the high
exothermicity is observed primarily during rapid polymerization of
unfilled or low-filled lower molecular weight acrylate monomers,
such compositions and requirements of fast cure are considered
highly desirable in certain clinical applications. Examples of
applications raising concern with regard to exothermic effects
generated during cure of acrylic monomers include cured or cemented
in situ medical and dental devices such as hip prostheses, dental
fissure sealers, temporary or permanent crowns and bridges and
cemented orthodontic appliances.
[0016] There were several prior attempts to address the problems
related to the shortcomings of acrylic resins. One such attempt was
to use high molecular weight monomethacrylate monomers. While this
approach effectively lowered the exothermic effect of the curing
process, the resulting polymer was mechanically weak, brittle and
the oxygen-inhibited layer was pronounced. A second attempt was to
use polyethylene glycols and/or polymeric particulate fillers as
inert, nonreactive ingredients. Although polymerization occurred
with no excessive heat, the cured material was brittle and cracked
easily, even when exposed to weak forces. Oxygen-inhibited layer
was, however, slightly reduced. A third attempt was to use
inorganic particulate fillers, however, the cured material was
brittle and very hard; although the exothermic effect of
polymerization and oxygen-inhibited layer were significantly
reduced. Another attempt was to add phthalic acid esters and other
polymers flexibilizing additives. It was found that such additives,
although efficient when incorporated in other type polymers, were
of little use in acrylic resin. In addition, concerns were raised
about their safety when employed in dental/medical materials.
[0017] Disclosed herein are modified, chemically-, heat- or
light-curable acrylate compositions and objects made of such
compositions. One of the principal features of such compositions,
in preferred embodiments, is their temporary or permanent
flexibility. (The term "temporary flexibility" is herein defined as
transient flexural characteristics of the material during a defined
time, usually 1-5 minutes after initial cure.) Such materials also
generally exhibit significant improvement over unmodified acrylic
polymers in their resistance to breaking under stress. In addition,
the oxygen-inhibited layer after polymerization is virtually or
entirely eliminated and, if desired, so is the exothermic effect
generated during the curing process of the formulations of this
invention.
[0018] In preferred embodiments, the compositions and objects made
of such compositions comprise:
[0019] 10-90% by weight of one or more esters of acrylic or
methacrylic acid containing one or more acrylate or methacrylate
moieties per molecule.
[0020] 1-60% by weight of one or more polymers or oligomers of
olefinic monomers having four to six carbon atoms and one or two
double bonds per molecule, such polymers preferably having
molecular weight of 300-2500 and viscosity of 25-4500 cp.
[0021] In the present specification and claims, ranges for
components such as those above mean that if there is one recited
component, it is present at a concentration within the stated range
(as compared to the weight of the entire composition) and if there
are two or more species of the recited component present, the total
combined weight of all such species will fall within the stated
range. Within the range is to be read as inclusive of the upper and
lower limits.
[0022] The composition optionally comprises one or more of one or
more of the following compounds and/or materials: polymerization
activating agents, UV absorbers, stabilizers for preventing
premature polymerization, organic and/or inorganic fillers,
colorants, such as pigments and/or dyes (for aesthetic, diagnostic
or use-facilitating purposes), and other desirable additives to
enhance mechanical or visual/optical properties of the material.
Polymerization activators include, but are not limited to, amines,
preferably tertiary amines, and/or peroxides. Preferred
polymerization activators include, but are not limited to, benzoyl
peroxide, halogen substituted derivatives of benzoyl peroxide, N,N
bis-(2-hydroxyethyl) p-toluidine, N,N diethyl-p-toluidine,
camphoroquinone, tertiary aliphatic amines, trialkylamines,
methacroylalkyl-dialkylamines, and combinations of the foregoing.
If present, the one or more polymerization activators are
preferably present at concentrations of about 0.5-2% by weight.
Stabilizers include, but are not limited to BHT, and, if
stabilizers are present, they are preferably present at about
0.01-0.1% by weight, or in sufficient quantity to prevent premature
polymerization of the material during storage and/or transport.
Preferred fillers include glass, silica (amorphous and/or fumed),
quartz silica, aluminum oxide, zirconium oxide, barium sulfate, and
mixtures thereof. If present, fillers preferably comprise about
10%-30% of the composition by weight, including about 15%-25%.
[0023] The composition may be produced and stored as a single part
or it may be as two or more parts, each of which has some or all of
the component chemicals and materials of the composition. The two
(or more) parts are mixed prior to application or use. Two or more
part formulations are preferred for those formulations of the
composition which self-cure or chemically cure. For those
compositions having two or more parts, the constitution of the
composition and the amounts of the component parts refer to the
composition following mixing, i.e. the composition as it is used.
Accordingly, the individual parts may comprise varying amounts of
materials and may be mixed in any proportion such as from 1:20
(v/v) to 20:1 (v/v), provided that the final composition is
according to the description herein. In a preferred embodiment, the
two parts (Part A and Part B) are mixed in a 1:1 (v/v) ratio by
hand or static mixer.
[0024] It was unexpectedly found that the addition of such olefinic
polymers to acrylic monomers results, after curing of such blends,
in a polymeric material having desirable flexural and other
mechanical properties, including resistance to impact and breakage.
These characteristics made them particularly useful in dental and
medical applications. The presence of such olefinic monomers did
not interfere with the curing process of the acrylic monomers
regardless of whether the curing was done by heat, by chemical
means or by light. In addition to desirable mechanical properties
of the cured acrylate monomers modified which such olefinic
polymers, the surfaces of the resulting product are free, or
virtually free, of the oxygen-inhibited layer. Furthermore, the
exothermic effect (high exothermicity) of polymerization is
virtually not detectable or insignificant.
[0025] The discovery of the present compositions came as a total
surprise, as polyolefins were known only as modifiers of
thermoplastic polymers and elastomers, and not for thermosetting
polymers, to which category acrylate polymers belong. Furthermore,
it was surprising to find that such olefinic polymers are
compatible with a large variety of acrylate monomers and/or their
blends, and are useful in a broad range of their molecular
weights.
[0026] Blends comprising olefinic polymers or oligomers, preferably
liquid polymers having molecular weights in the range of
approximately 100-700, and aliphatic or aromatic acrylate monomers
were found to be particularly advantageous in certain aspects. In
some applications, methacrylic acid esters are preferred over
acrylic acid ones.
[0027] The acrylate component of preferred compositions preferably
comprises about 10-90% by weight of an acrylic monomer or a blend
of acrylic monomers, including about 50-80%, about 60-80%, about
50-70%, about 60-80%, about 70-80%, and about 50-60% by weight. As
used herein, a composition comprising a monomer may be purely
monomers, or it may contain some or all of dimers, trimers or other
oligomers. The acryate component comprises esters of acrylic or
methacrylic acid containing one or more acrylate or methacrylate
moieties per molecule. Examples of acrylate monomers suitable for
use in formulations of this invention include, but are not limited
to: ethylene and propylene glycol dimethacrylates, di-, tri- and
polyethylene and propylene glycol dimethacrylates (including, but
not limited to, di-polyethylene glycol dimethacrylate,
tri-polyethylene glycol dimethacrylate, di-propylene glycol
dimethacrylate, and tri-propylene glycol dimethacrylate),
tri-methylolopropane trimethacrylate, hydroxyethyl methacrylate,
hydroxypropyl methacrylate, tetrahydrofurfuryl methacrylate,
1,6-hexanediol dimethacrylate
7,7,9-trimethyl-4,13-dioxo-3,14-dioxa-
-5,12-diazahexadecane-1,16-diol dimethacrylate (commonly known as
diurethane dimethacrylate),
2,2-bis[4-(2-hydroxy-3-methacryloylpropoxy)phenyl]propane (commonly
known as bis-GMA) and ethoxylated bisphenol-A-dimethacrylate
(commonly known as EBA). In certain applications, the use of the
following aliphatic monomethacrylate monomers, preferably in
mixtures with di- or poly-dimethacrylates is desirable:
C.sub.1-C.sub.12 alkyl methacrylates, cyclohexyl methacrylate,
hydroxy-(C.sub.2-C.sub.4) alkyl methacrylates and glycerol
methacrylates.
[0028] The olefinic component of preferred compositions preferably
comprise about 1-60% by weight of polymers or oligomers of olefinic
monomers having four to six carbon atoms, including about 1-10%,
about 1-20%, about 10-20%, about 10-30%, about 1-40%, and about
10-40% by weight. Examples of suitable olefinic polymers or
oligomers include various olefinic polymers or oligomers derived
from C.sub.4-C.sub.6 mono- or bi-unsaturated monomers, preferably
those originated or derived from monomers having four carbon atoms
in their lineal chain such as butene, butadiene or methyl butadiene
(isoprene). In most applications polybutene is preferred, being
inexpensive and commercially available in a desirable range of
molecular weights.
[0029] The compositions disclosed herein may be formed or molded
into medical devices or used as a cement in a medical application,
such as a bone cement in orthopedic surgical procedures. The
materials may also be molded or formed to create a prosthesis or
dental restorative, or it may be applied to a tooth and/or a dental
appliance (including but not limited to crowns, bridges, whether
permanent or temporary), thereby being used as a cement, cavity
liner, varnish, sealer, veneer or a "bonding" material to fill in
dental imperfections or a missing portion of a tooth. In accordance
with one embodiment, there is provided a method of performing a
dental procedure, comprising obtaining a curable composition as
disclosed herein in various embodiments; applying the composition
to at least one surface of a tooth or dental appliance; and
allowing the composition to cure. Accordingly, this disclosure also
includes the use of a curable composition as disclosed herein as a
cement, cavity liner, varnish, sealer, veneer, bonding material,
prosthesis or dental restorative in the treatment of a diseased
tooth (such as a tooth having a cavity or decay (caries)), broken
tooth, or discolored tooth.
[0030] The following examples are given for better understanding of
the character of this invention and ways of its implementation;
however, with no intention of outlining its scope, defined in the
claims.
EXAMPLE 1
[0031] A heat curable composition consisted of:
TABLE-US-00001 %(by weight) Diurethane dimethacrylate 73.58
Polybutene 9.68 BHT 0.05 Benzoyl peroxide 1.06 Silica 15.63
[0032] The components were mixed and the material composition was
cured in the oven at 100.degree. C. for 1 hour. The properties of
cured material are: Barcol hardness: 25-30; Flexural strength: 71
Mpa. The product was judged suitable for intended use, such as for
a temporary crown and bridge material.
EXAMPLE 2
[0033] A light curable composition consisted of:
TABLE-US-00002 %(by weight) Diurethane dimethacrylate 73.75
Polybutene 8.38 Camphoroquinone 0.26 Methacroyl ethyl diethylamine
0.75 Silica 16.86
[0034] The material was mixed and then cured for 20 seconds using
an Optilux.RTM. dental curing device (light curing). The product
was judged suitable for intended use.
EXAMPLE 3
[0035] A chemically curable composition consisted of a 1:1 (v/v)
mixture of Parts A and B:
TABLE-US-00003 %(by weight) Part A Diurethane dimethacrylate 78.96
N,N bis(2-hydroxyethyl)-p-toluidine 0.39 Silica 20.65 Part B
Diurethane dimethacrylate 73.58 Polybutene 9.68 BHT 0.05 Benzoyl
peroxide 1.06 Silica 15.63
[0036] The material was soft cured in 110 seconds and hard cured in
150 seconds at 23.degree. C. (soft cure is defined as a stage at
which the material becomes solid but exhibits flexibility). The
properties of cured material are: Barcol hardness: 42-45; Flexural
strength: 61 Mpa. The product was judged suitable for use.
EXAMPLE 4
[0037] A self curable composition consisted of a 1:1 (v/v) mixture
of Parts A and B:
TABLE-US-00004 %(by weight) Part A EBA 17.29 Triethylene glycol
dimethacrylate 20.47 Bis-GMA 14.09 Polybutene 30.18 BHT 0.01 N,N
bis(2-hydroxyethyl)-p-toluidine 1.87 Silica 16.09 Part B EBA 18.61
Triethylene glycol dimethacrylate 21.7 Bis-GMA 14.88 Polybutene
16.28 BHT 0.08 Benzoyl peroxide 0.77 Silica 27.68
[0038] The material reached soft curing stage in 175 seconds and
hard cured in 210 seconds at 23.degree. C. The product was judged
suitable for use, but was somewhat inferior to the product of
Example 3.
EXAMPLE 5
[0039] An alternative self curable composition similar to that of
Example 3 but with different filler, consisted of a 1:1 (v/v)
mixture of Parts A and B:
TABLE-US-00005 %(by weight) Part A Diurethane dimethacrylate 53.92
N,N bis(2-hydroxyethyl)-p-toluidine 0.38 Silica 12.97 Glass powder
32.73 Part B Diurethane dimethacrylate 73.58 Polybutene 9.68 BHT
0.05 Benzoyl peroxide 1.06 Silica 15.63
[0040] The cured material had similar properties to that of Example
3.
EXAMPLE 6
[0041] A chemically curable composition similar to that of Example
3, but with different flexibilizing additive (polybutadiene instead
of polybutene), consisted of a 1:1 (v/v) mixture of Parts A and
B:
TABLE-US-00006 %(by weight) Part A Diurethane dimethacrylate 79.09
N,N bis(2-hydroxyethyl)-p-toluidine 0.56 Silica 20.35 Part B
Diurethane dimethacrylate 67.03 Polybutadiene 12.21 BHT 0.08
Benzoyl peroxide 1.00 Silica 19.68
[0042] The material reached soft curing stage in 85 seconds and
hard cured in 140 seconds at 23.degree. C. The product was judged
suitable for use.
EXAMPLE 7 (REFERENCE)
[0043] A chemically curable composition similar to that of Example
3 but not containing flexibilizing additive (polybutene), consisted
of a 1:1 (v/v) mixture of Parts A and B:
TABLE-US-00007 %(by weight) Part A Diurethane dimethacrylate 72.77
N,N bis(2-hydroxyethyl)-p-toluidine 0.51 Silica 26.72 Part B
Diurethane dimethacrylate 76.33 BHT 0.05 Benzoyl peroxide 1.15
Silica 22.47
[0044] The properties of cured material are: Barcol hardness:
50-55; Flexural strength: 83 Mpa. The cured product was judged not
suitable as a temporary crown and bridge material because of lack
of flexibility.
* * * * *