U.S. patent application number 11/166320 was filed with the patent office on 2005-12-01 for silver-containing dental composition.
This patent application is currently assigned to Kerr Corporation. Invention is credited to Qian, Xuejun.
Application Number | 20050265931 11/166320 |
Document ID | / |
Family ID | 29717853 |
Filed Date | 2005-12-01 |
United States Patent
Application |
20050265931 |
Kind Code |
A1 |
Qian, Xuejun |
December 1, 2005 |
Silver-containing dental composition
Abstract
A dental composition comprising a silver-containing ceramic
having antimicrobial and color stabilizing properties and methods
for using the composition. The composition comprises a
silver-containing glass powder or a silver-containing zeolite
powder, at least one monomer having at least one ethylenically
unsaturated group, and a polymerization initiator system. Other
components, such as a filler, may also be included. The inventive
composition possesses antimicrobial properties and exhibits
excellent mechanical properties upon curing. Additionally, when the
polymerization initiator is a two-part redox initiator system, the
composition has improved color stability. The inventive composition
can be used as a dental restorative composition, an endodontic
composition, an orthodontic composition, and/or a prosthetic
composition.
Inventors: |
Qian, Xuejun; (Foothill
Ranch, CA) |
Correspondence
Address: |
WOOD, HERRON & EVANS, LLP
2700 CAREW TOWER
441 VINE STREET
CINCINNATI
OH
45202
US
|
Assignee: |
Kerr Corporation
Orange
CA
92867
|
Family ID: |
29717853 |
Appl. No.: |
11/166320 |
Filed: |
June 24, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11166320 |
Jun 24, 2005 |
|
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10177055 |
Jun 21, 2002 |
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6924325 |
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Current U.S.
Class: |
424/49 ;
523/115 |
Current CPC
Class: |
A61K 6/869 20200101;
A61K 6/887 20200101; A61K 6/30 20200101; A61K 6/20 20200101; A61K
6/69 20200101 |
Class at
Publication: |
424/049 ;
523/115 |
International
Class: |
A61K 007/16; A61F
002/00 |
Claims
What is claimed is:
1. A dental composition comprising a silver zinc zeolite, at least
one monomer having at least one ethylenically unsaturated group, a
polymerization initiator, and at least one finely divided filler
selected from the group consisting of an inorganic salt, an
inorganic oxide, and combinations thereof.
2. The composition of claim 1 wherein the inorganic oxide is zinc
oxide.
3. The composition of claim 1 wherein the filler has a mean
particle size of less than about 20 .mu.m.
4. The composition of claim 1 wherein silver zinc zeolite is at a
concentration in the range of about 0.01%.sup.w/w to about
10%.sup.w/w of the composition.
5. The composition of claim 1 wherein the silver zinc zeolite is a
powder.
6. The composition of claim 5 wherein the silver zinc zeolite
powder has a mean particle size less than about 30 .mu.m.
7. The composition of claim 5 wherein the silver zinc zeolite
powder is aluminosilicate zeolite with silver ions and zinc ions at
ion-exchangeable sites.
8. The composition of claim 7 wherein the aluminosilicate zeolite
is selected from the group consisting of A zeolite, X zeolite, Y
zeolite, mordenite, and combinations thereof.
9. The composition of claim 1 wherein the ethylenically unsaturated
group is selected from the group consisting of a vinyl group, a
methacrylate group, an acrylate group, and combinations
thereof.
10. The composition of claim 1 wherein the polymerization initiator
is selected from the group consisting of a photo-initiator, a redox
initiator, a heat initiator, and combinations thereof.
11. The composition of claim 1 wherein the silver zinc zeolite
further comprises copper.
12. The composition of claim 1 further comprising a component
selected from the group consisting of a second filler, a solvent, a
colorant, a stabilizer, an ultraviolet light absorber, and
combinations thereof.
13. The composition of claim 12 wherein the second filler is
selected from the group consisting of inorganic metal, silicate,
aluminosilicate, aluminoborosilicate, fluoroaluminosilicate,
colloidal silica, precipitated silica, polymeric filler,
polymerized composite filler with inorganic particles,
bariumaluminosilicate, bariumaluminoborosilicate,
strontiumaluminosilicate, zincaluminosilicate,
bariumaluminofluorosilicat- e, strontiumaluminofluorosilicate,
zirconia, zirconiumaluminosilicate, fumed silica, and combinations
thereof.
14. The composition of claim 12 wherein the solvent is selected
from the group consisting of water, acetone, methanol, ethanol,
isopropanol, and combinations thereof.
15. The composition of claim 1 wherein the composition is selected
from the group consisting of a resin composite, a resin-ionomer,
and a resin-modified glass-ionomer.
16. The composition of claim 1 wherein the composition is selected
from the group consisting of a restorative composition, an
endodontic composition, an orthodontic composition, a prosthetic
composition, and combinations thereof.
17. The composition of claim 16 wherein the restorative composition
is selected from the group consisting of a filling material, a
cement, a liner, a base, a primer, an adhesive, a sealant, a
sealer, an inlay, an onlay, a crown, a bridge, a denture, and
combinations thereof.
18. The composition of claim 1 for use to improve color
stability.
19. A dental composition comprising a silver zinc zeolite, at least
one monomer having at least one ethylenically unsaturated group, a
polymerization initiator, and a zinc oxide filler.
20. The composition of claim 19 further comprising a component
selected from the group consisting of a second filler, a solvent, a
colorant, a stabilizer, an ultraviolet light absorber, and
combinations thereof.
21. A dental composition comprising at least one monomer having at
least one ethylenically unsaturated group, a polymerization
initiator, and a composition comprising a silver zinc zeolite and
zinc oxide.
22. The composition of claim 21 further comprising a component
selected from the group consisting of a second filler, a solvent, a
colorant, a stabilizer, an ultraviolet light absorber, and
combinations thereof.
23. A method for providing an antimicrobial composition to a tooth
comprising preparing the composition of any of claims 1, 2, 12, 19,
20, 21, or 22, and providing the composition to the tooth.
24. The method of claim 23 further comprising the step of curing
the composition after providing the composition to the tooth.
25. The method of claim 23 further comprising the step of curing
the composition before providing the composition to the tooth.
Description
RELATED APPLICATION
[0001] This application is a Divisional of U.S. patent application
Ser. No. 10/177,055, filed on Jun. 21, 2002, the disclosure of
which is hereby incorporated herein by reference in its
entirety.
FIELD OF THE INVENTION
[0002] This invention relates to a dental composition comprising a
silver-containing ceramic that exhibits antimicrobial properties
and improved color stability without compromising mechanical
properties.
BACKGROUND OF THE INVENTION
[0003] Resin based dental restorative materials are becoming the
material of choice by dentists and patients due to their desirable
aesthetic properties. However, gap formation occurs between the
restorative material and tooth structure as a result of inadequate
adhesive bonding, polymerization shrinkage stress, thermal stress,
and mechanical stress (mastication force). This leads to
microleakage and, subsequently, secondary caries.
[0004] A restorative material that possesses antibacterial
properties and inhibits bacterial growth around the restoration
would be desirable. Various antibacterial agents have been
incorporated into oral products such as rinse solutions,
toothpastes, coatings, and dental restorative compositions to kill
bacteria or inhibit bacterial growth. Those antibacterial agents
include phenols/essential oils (U.S. Pat. Nos. 5,260,062 and
6,326,417), quaternary ammonium compounds (U.S. Pat. Nos.
4,820,507; 5,330,746; and 6,355,704), and metal salts containing
zinc (U.S. Pat. No. 4,522,806).
[0005] Silver has been shown to be an effective antibacterial
agent. For example, U.S. Pat. No. 5,340,850 discloses a method to
physically implant silver ions onto the surface of an inorganic
filler or into a resin matrix using a special ion implantation
apparatus. U.S. Pat. No. 6,379,712 discloses a
nanosilver-containing antibacterial granule comprising a metallic
silver core surrounded by silver oxide, obtained by precipitating
silver from solution onto cut stalk marrow, and grinding the
nanosilver-containing stalk marrow. U.S. Pat. No. 6,267,590
discloses an orthodontic dental bracket and arch wire coated with
an antimicrobial polymeric coating composition comprising a zeolite
particle containing silver ions. U.S. Pat. No. 4,911,898 discloses
preparation of zeolite particles containing silver ions having
antibacterial properties, prepared by doping the zeolite particle
with silver ions through ion-exchange in a silver-ion-containing
aqueous solution.
[0006] None of the aforementioned references disclose a dental
composition containing ethylenically unsaturated monomers and
polymerization initiators in which a silver-containing ceramic
provides desirable properties, such as antimicrobial properties and
color stabilization, without sacrificing the mechanical strength of
the dental composition.
SUMMARY OF THE INVENTION
[0007] One embodiment of the invention is directed to an
antimicrobial dental composition comprising a silver-containing
ceramic, at least one monomer having at least one ethylenically
unsaturated group, and a polymerization initiator system. The
composition may contain other components such as a filler, a
stabilizer, an ultraviolet light absorber, a colorant, solvents to
modify its viscosity, etc. The silver containing ceramic is either
a glass powder or a zeolite powder; in one embodiment it is present
at a concentration in the range of about 0.01%.sup.w/w to about
10%.sup.w/w of the composition, and in another embodiment it is
present in the range of about 0.05%.sup.w/w to about 5%.sup.w/w of
the composition. In one embodiment the powder mean particle size is
less than about 30 .mu.m, and in another embodiment the powder mean
particle size is less than about 5 .mu.m. The glass powder may be
silveraluminophosphate glass or silveraluminosilicate glass. The
zeolite powder may be aluminosilicate zeolite with silver ions at
its ion-exchangeable sites. The silver containing ceramic may also
include other elements, such as copper and zinc. The ethylenically
unsaturated group in the composition may be a vinyl group, a
methacrylate group, and/or an acrylate group. The polymerization
initiator system in the composition may be a photo-, redox-, and/or
a thermal initiator system. The composition may be a resin
composite, a resin-ionomer, and/or a resin-modified
glass-ionomer.
[0008] Another embodiment of the invention is directed to a
color-stabilized two-part (catalyst part and base part) dental
composition comprising a silver-containing ceramic, at least one
monomer having at least one ethylenically unsaturated group, and a
redox polymerization initiator system with each part containing one
component of the redox initiator system. The catalyst part
containing the oxidizing agent of the redox initiator system, such
as a peroxide, exhibits improved shelf color stability when a
silver-containing ceramic is incorporated. The composition may
optionally contain a filler.
[0009] Another embodiment of the invention is a method of providing
an antimicrobial composition to a tooth. A composition of a
silver-containing ceramic antimicrobial, at least one monomer
having at least one ethylenically unsaturated group, and a
polymerization initiator system is prepared. The composition may
optionally contain a filler. The composition may be provided to the
tooth and then cured, or may be cured and then provided to the
tooth. The composition may be used as a dental restorative
composition, an endodontic composition to seal and/or fill a root
canal, an orthodontic composition, or a prosthetic composition.
[0010] These and other embodiments of the inventive composition
will be apparent in light of the following detailed description and
examples.
DETAILED DESCRIPTION OF THE INVENTION
[0011] The inventive composition comprises a silver-containing
ceramic, one or more monomers having at least one ethylenically
unsaturated functional group, and a polymerization or curing
initiator system. The silver-containing ceramic, providing an
antimicrobial effect, may be either a silver-containing glass
powder or a silver-containing zeolite powder, and may contain
additional antimicrobial agents such as zinc and/or copper. Other
components may also be included, such as a filler, a colorant, a
stabilizer to improve the shelf-life of the composition, a
stabilizer against the effects of ultraviolet (UV) light, etc.
[0012] The silver-containing ceramic provides a sustained release
of active components, i.e. silver, into an oral environment
surrounding a restoration, and helps to prevent secondary caries
adjacent to the restoration where gaps develop between the
restoration and the tooth structure. When incorporated into dental
restorative compositions, the mechanical strength, optical
properties, and shelf-stability of the resulting material was not
compromised.
[0013] The silver-containing ceramic and at least one monomer
having at least one ethylenically unsaturated group may be used in
a two-part dental composition containing a redox polymerization
initiator. The two parts are the catalyst part and the base part,
with each part containing one component of the redox initiator
system. The base part usually contains the reducing agent of the
redox initiator system, while the catalyst part contains the
oxidizing agent of the redox initiator system. The composition is
cured when the catalyst part is mixed with the base part,
initiating free radical polymerization, and the composition is said
to be a self-cure composition (without external activation source
such as light or heat). A photo-initiator can be optionally
incorporated in the base part of the composition to obtain a
dual-cure (self-cure and light-cure) two-part composition. It was
known to dental manufacturers and dental practitioners that the
catalyst part containing the oxidizing agent generally had a
limited color stability and became discolored after storage for
about six months. However, when the silver-containing ceramic was
incorporated into the composition, the catalyst part exhibited
significantly improved color stability, providing a two-part dental
composition of more consistent color.
[0014] The silver-containing ceramic is a silver-containing glass
powder or a silver-containing zeolite powder. In one embodiment,
the powders have a mean particle size of less than 30 .mu.m. In
another embodiment, the powders have a mean particle size less than
5 .mu.m. The silver-containing glass can be silveraluminophosphate
glass or silveraluminosilicate glass. The glass may also contain
other antibacterial elements, such as zinc and/or copper, to
enhance the antimicrobial effect. During the glass making process,
additional elements may be introduced for ease of manufacture, for
imparting radiopacity to the dental composition, for release of
fluoride, etc. Examples of such elements include boron, phosphor,
fluorine, calcium, barium, strontium, or other alkali/alkaline
metal elements. The silver is incorporated into the glass by
melting together the silver-containing compound with other glass
forming ingredients during manufacture of the glass. One
silver-containing glass antimicrobial additive is Irgaguard.RTM.
B7000 (Ciba Specialty Chemicals Corporation, Tarrytown N.Y.).
Irgaguard.RTM. B7000 is a mixture of silver-zinc glass fine powder
and barium sulfate fine powder, with a mean particle size of 1.8
.mu.m.
[0015] The silver-containing zeolite powder can be prepared by
replacing some or all of the ion-exchangeable metal ions, usually
alkali or alkaline metal ions, of zeolite particles with silver
ions through an ion-exchange process in an aqueous solution
containing silver ions. Antibacterial zeolites and their
preparation are disclosed in U.S. Pat. Nos. 4,911,899 and
4,775,585, each of which is expressly incorporated by reference
herein in its entirety. Either natural or synthetic zeolite may be
used. Zeolite is generally aluminosilicate having a
three-dimensional grown skeleton structure generally expressed by
xM.sub.2/nO Al.sub.2O.sub.3 ySiO.sub.2 zH.sub.2O where M represent
an ion-exchangeable metal (alkali or alkaline) ion; n represent the
valence of the metal; x is the molar coefficient of the metal oxide
in relation to Al.sub.2O.sub.3; and y is the molar coefficient of
silica in relation to Al.sub.2O.sub.3; z is the number of water of
crystallization. Zeolites include A zeolite, Z zeolite, Y zeolite,
and mordenite. Other antimicrobial metal ions such as zinc and
copper ions, in addition to silver ions, can also be incorporated
by the ion-exchange process. In one embodiment, silver-zinc zeolite
is used where silver ions and zinc ions are incorporated onto the
ion-exchangeable sites of the zeolite through an ion-exchange
process. One silver-zinc zeolite is Irgaguard.RTM. B5000 (Ciba
Specialty Chemicals Corporation, Tarrytown N.Y.). Irgaguard.RTM.
B5000 has a mean particle size of 0.3 .mu.m.
[0016] The concentration range for the silver-containing ceramic
ranges from about 0.01%.sup.w/w to about 10%.sup.w/w of the
composition. In one embodiment, the concentration range is from
about 0.05%.sup.w/w to about 5.0%.sup.w/w of the composition.
[0017] Any monomers having at least one ethylenically unsaturated
group may be used. Examples of ethylenically unsaturated groups
include vinyl, acrylate, and methacrylate groups. Examples of
monomers include, but are not limited to, the following, where
(meth)acrylate denotes acrylate or methacrylate: hydroxyethyl
(meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl
(meth)acrylate; glycerol di(meth)acrylate, glycerol
mono(meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate,
propyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate,
octyl (meth)acrylate, lauryl (meth)acrylate, decyl (meth)acrylate,
tridecyl (meth)acrylate; 2-ethoxyethyl (meth)acrylate,
2'-ethoxy-2-ethoxyethyl (meth)acrylate, ethyleneglycol
di(meth)acrylate, diethyleneglycol di(meth)acrylate,
triethyleneglycol di(meth)acrylate, tetraethyleneglycol
di(meth)acrylate, polyethyleneglycol mono-(meth)acrylate,
polyethyleneglycol di-(meth)acrylate, polypropyleneglycol
mono-(meth)acrylate, polypropyleneglycol di-(meth)acrylate,
polytetramethyleneglycol mono-(meth)acrylate,
polytetramethyleneglycol di-(meth)acrylate, hexanediol
di(meth)acrylate, trimethyloylpropane tri(meth)acrylate, UDMA
(reaction product of 2-hydroxyethyl methacrylate with
2,4,4-trimethylhexane diisocyanate),
2,2-bis[4-(2-hydroxy-3-methacry- loylpropoxy)-phenyl]-propane
(Bis-GMA), ethoxylated bisphenol A dimethacrylate (EBPADMA-n, n is
the total number of moles of ethylene oxide in the molecule; in one
embodiment n is 2-20 units), tetrahydrofurfuryl (meth)acrylate, or
a mixture thereof. In various embodiments, the monomers contain
more than one ethylenically unsaturated group per molecule.
[0018] The free-radical polymerization initiator may be any
initiator that can initiate free radical polymerization of monomers
with an ethylenically unsaturated group, and may be one or more
photo-initiator(s), redox initiator(s), and/or heat (thermal)
initiator(s). Examples of photo-initiators include benzoin, benzoin
ethers and esters, 2,2-diethoxy acetophenone, diketone compounds,
bisacylphosphine oxide, diaryliodonium salt, and/or
triarylsulfonium salt. Additionally, an activator such as a
tertiary amine can be used with the photo-initiators to enhance
curing efficiency. Photo-initiator systems may include
camphoroquinone and a tertiary amine such as ethyl
4-(N,N-dimethylamino) benzoate,
2-(ethylhexyl)-4-(N,N-dimethylamino) benzoate, and
N,N-dimethylaminoethyl methacrylate. A redox initiator system has
at least one reducing agent and at least one oxidizing agent. The
reducing agent may be a tertiary amine or an organic compound
containing the --SO.sub.2M (where M is H or alkali metal ion)
group. In various embodiments, the reducing agent may be
N,N-dihydroxyethyl p-toluidine, N,N-dimethyl p-toluidine,
N,N-dimethylaminophenylethyl alcohol, N,N-dimethylaminophenylacetic
acid, benzenesulfinic acid, toluenesulfinic acid, sodium
benzenesulfinate, potassium benzenesulfinate, sodium
toluenesulfinate, potassium toluenesulfinate. The oxidizing agent
may be a peroxide, such as benzoyl peroxide, hydrogen peroxide,
di-t-butyl peroxide, t-butyl hydrogen peroxide. A heat initiator
may be a peroxide, persulfate, or azo compound, such as benzoyl
peroxide, potassium persulfate, 2,2'-azo-bis(isobutyron itrile),
and 1,1'-azo-di-(hexahydrobenzonitrile).
[0019] The photo-initiator, redox initiator, and heat initiator can
be used alone or in combination. A heat initiator may be used in a
single part, heat-cure only system such as in an inlay, onlay, or
crown composition. A photo-initiator may be used in a single part,
light-cure only system, such as in a light-cure composite filling
material or light-cure veneer cement. The redox initiator may be
used in a two-part self-cure (i.e. curing without the activation of
light or heat) composition with each part containing one component
(either the oxidizing agent or the reducing agent) of the redox
initiator system. The photo-initiator can be used in combination
with the redox initiator system to make the system dual-cure, i.e.
both light-cure and self-cure. The heat-cure initiator and
photo-initiator can be used together in a single part dual-cure
system, i.e. both light-cure and heat-cure. The concentration of
the initiator(s) is in the range of about 0.01%.sup.w/w to about
5.0%.sup.w/w. In one embodiment, the concentration of the
initiator(s) is in the range of about 0.05%.sup.w/w to about
3.0%.sup.w/w.
[0020] A filler is optional, depending upon the application. While
most compositions require the use of a filler, a primer or an
adhesive composition may not contain a filler. A filler may be used
to enhance mechanical properties, reduce polymerization shrinkage,
improve rheological properties, and increase radiopacity of the
composition for easy detection of gaps or voids. Examples of
fillers include inorganic metal, salt, oxide, silicate,
aluminosilicate, aluminoborosilicate, fluoroaluminosilicate,
colloidal silica, precipitated silica, polymeric filler, and/or
polymerized composite filler with reinforcing inorganic particles.
Inorganic fillers for increased x-ray contrast include metals,
silicates, aluminosilicates, salts and oxides containing elements
of high atomic number including strontium, bismuth, tungsten,
barium, yterbium, ytrium etc. Examples include barium sulfate,
silver, strontium fluoride, barium fluoride, yterbium fluoride,
ytrium fluoride, barium tungstate, zinc oxide, zirconia,
bismuth(III) oxide, bariumaluminosilicate,
bariumaluminoborosilicate, strontiumaluminosilicate,
bariumaluminofluorosilicate, strontiumaluminofluorosilicate,
zincaluminosilicate, zirconiumaluminosilicate, etc. Fumed silica,
colloidal silica, or precipitated silica can also be incorporated
to improve the dispersion of the filler, as well as the rheological
and handling properties of the material. Examples of colloidal
silicas are "Aerosil" series "OX-50", "OX-130", and "OX-200" silica
sold by Degussa (Ridgefield Park N.J.), "Cab-O-Sil M5" and
"Cab-O-Sil TS-530" silica sold by Cabot Corporation (Tuscola Ill.).
The fillers also include nano-particles fillers such as those
obtained through sol-gel process as disclosed in U.S. Pat. Nos.
4,567,030 and 5,609,675, the disclosure of each is expressly
incorporated by reference herein in its entirety. Mixtures of
different fillers can be used.
[0021] For inorganic fillers, the surface of the filler may be
treated or coated with a coupling agent such as
amma-methacryloyloxypropyltrimethoxy- silane (A-174). A coupling
agent enhances the interfacial bonding between the filler and resin
matrix, and improves mechanical properties of the composition. Mean
particle sizes of the filler are less than 20 .mu.m, and in one
embodiment are less than 5 .mu.m. The concentration range of total
filler(s) is 0% up to about 95% by weight, depending on the
application. For primer or adhesive applications, the concentration
range is 0% up to about 60%. For cement applications, the
concentration range is about 20% up to about 75%. For filling
materials, the concentration range is about 30% up to about
95%.
[0022] Other components may be incorporated in the inventive
composition, including colorants, stabilizers, UV absorbers, and
other antimicrobials. Colorants are used to achieve a desired
shade, and may be inorganic pigments or organic dyes. Stabilizers
are polymerization inhibitors to improve the shelf stability of the
composition. Most commonly used stabilizers include
2,6-di-(tert-butyl).sub.4-methylphenol (BHT) and 4-methoxyphenol
(MEHQ). UV absorbers are used to improve the color stability of the
restorative material upon exposure to UV light. An example of UV
absorber is 2-hydroxy-4-methoxybenzophenone (UV-9).
[0023] The inventive compositions may be used as a dental
restorative composition, an endodontic composition, an orthodontic
composition, or a prosthetic composition. A restorative composition
may be a dental filling material, a dental cement, a dental liner,
a dental base, a dental primer, a dental adhesive, or a dental
pit/fissure sealant composition. An endodontic composition may be
an endodontic sealing and/or filling material for sealing and/or
filling of a root canal. These may be of the type disclosed in U.S.
Pat. No. 6,353,041 and co-pending application Ser. No. 09/657,961,
each of which is expressly incorporated by reference herein in its
entirety. An orthodontic composition may be an orthodontic primer,
adhesive, or cement composition for adhering an orthodontic
appliance to a tooth surface. A prosthetic composition may include
a dental inlay, onlay, crown, bridge, or a denture composition.
[0024] The composition may be a purely resin-based composite, or
may be a hybrid material such as a resin-ionomer (RI) or
resin-modified glass-ionomer (RMGI), as disclosed in U.S. Pat. Nos.
5,859,089; 6,127,451; 4,872,936; 5,063,257; 5,154,762, each of
which is expressly incorporated by reference herein in its
entirety. RMGI is a hybrid material that contains at least an
acidic monomer or polymer, water, a monomer with at least one
ethylenically unsaturated group, an ion-leachable filler that can
undergo a setting reaction with the acidic monomer or polymer, and
a polymerization initiator. The acidic monomer or polymer
preferably contains at least one ethylenically unsaturated group.
The polymerization initiator can be a photo-initiator, a redox
initiator, or a combination of both. A resin-ionomer material, also
called a compomer, contains at least an acidic monomer with at
least one ethylenically unsaturated group, at least one co-monomer
with at least one ethylenically unsaturated group, an ion-leachable
filler, and a polymerization initiator. A resin-ionomer does not
contain water as an intentionally added component.
[0025] The inventive composition may also incorporate a solvent,
which may be used to modify the viscosity of the composition. In
one embodiment, the solvent is added when a primer, an adhesive, or
cement composition is formulated. Solvents include water, methanol,
ethanol, isopropanol, acetone, and methyl ethyl ketone (MEK).
[0026] The inventive composition is applied to the tooth or tooth
structure, t hen is hardened or cured (intra-oral curing) through
free radical polymerization. If the composition is used as a
permanent prosthetic such as a crown/bridge or denture material,
the composition is cured extra-orally through free radical
polymerization by light, heat, and/or a redox initiator system, and
is then adhered to the prepared dentition using an adhesive and/or
a cement.
EXAMPLES
[0027] The following examples illustrate how the composition is
applied and do not limit the scope of the invention.
[0028] Bacterial Growth Inhibition Test
[0029] A bacteria growth inhibition test against Streptococcus
mutans was conducted according to American Association of Textile
Chemist and Colorist (MTCC) Test Method 100. Cured specimens of 38
mm.times.38 mm square plate with a thickness of 0.4 mm were
prepared and inoculated with .about.2.times.10.sup.5 CFU (colony
forming unit) of Streptococcus mutans. Plate counts were performed
at the time of inoculation (0 time) and after 24 hours of
incubation at 37 C. The percent of bacterial reduction was
determined from the counts taken at 0 time and after 24 hours
incubation.
[0030] Compressive Strength (CS) Test
[0031] The specimens were prepared by condensing the paste into a
stainless-steel mold with a dimension of 4 mm (diameter).times.3 mm
(height), and then photo-curing the paste with a Demetron Optilux
401 curing light (Kerr Corporation, Orange Calif.) for 30 seconds
from each side. The cured disk was removed from the mold and
conditioned in 37.degree. C. water for 24 hours before subjecting
to mechanical testing on an Instron Universal Tester (Model 4202)
in compression mode with a crosshead speed of 0.50 mm/minute. The
peak load at which the specimen broke was used to calculate the
compressive strength and was expressed in MPa unit. Six specimens
were tested for each formula.
[0032] Diametral Tensile Strength (DTS) Test
[0033] The specimens were prepared by condensing the paste into a
stainless-steel mold with a dimension of 6 mm (diameter).times.3 mm
(height), and then photo-curing the paste with a Demetron Optilux
401 curing light (Kerr Corporation, Orange Calif.) for 30 seconds
from each side. The cured disk was removed from the mold and
conditioned in 37 C water for 24 hours before subjecting to
mechanical testing on an Instron Universal Tester (Model 4202) in
compression mode with a crosshead speed of 10 mm/minute. The load
was applied in the diameter direction in compression mode. The peak
load at which the specimen broke was used to calculate the
compressive strength and was expressed in MPa units. Six specimens
were tested for each formula.
[0034] Flexural Strength (FS) and Young's Modulus (E) Tests
[0035] FS and E were measured from the same flexural test according
to ISO 4049 standard as known to one skilled in the art. The
specimens were prepared by condensing the paste into a
stainless-steel mold with a dimension of 2 mm.times.2 mm.times.25
mm, and then photo-cured from both sides. The cured disk was
removed from the mold and conditioned in 37.degree. C. water for 24
hours before subjecting to mechanical testing on an Instron
Universal Tester (Model 4202) in three-point bending mode with a
crosshead speed of 0.5 mm/minute. The peak load at which the
specimen broke was used to calculate the FS and was expressed in
MPa units. E was obtained from the slope of stress-strain curve in
the initial linear region. Six specimens were tested for each
formula.
[0036] Color Measurement
[0037] Color measurement was conducted using a portable
spectrophotometer (Model SP60, X-Rite Inc.) in reflectance mode
against the white background of an opacity card (Form 2A, Leneta
Co.). The color is expressed as L*a*b* using the CIELAB scale where
L* defines the lightness, a* denotes the red/green value, and b*
denotes the yellow/blue value. For color measurement, 1 mm thick
specimens were used.
Example 1
[0038] Three pastes (A, B and C) were made based on Nexus.TM. 2
base clear paste (Kerr Corporation, Orange Calif.). Bacterial
growth inhibition tests according to the AATCC 100 method were
conducted on thethhree compositions. Paste A was same as Nexus.TM.
2 base clear shade composition and served as the control, paste B
was made by incorporating 3.0% Irgaguard.RTM. B7000 (an
antimicrobial silver-zinc glass powder from Ciba Specialty
Chemicals Corporation, Tarrytown N.Y.) into Nexus.TM. 2 base clear
shade composition, and paste C was made by incorporating 0.4%
Irgaguard.RTM. B5000 (an antimicrobial silver-zinc zeolite from
Ciba Specialty Chemicals Corporation) into Nexus.TM. 2 base clear
composition. The specimens for the bacterial inhibition test were
prepared according to above described method and the curing of the
specimen was achieved by light-curing the specimen for one
minute.
[0039] The results of the bacterial growth inhibition test against
Streptococcus mutans are shown in Table 1. While Paste A (Nexus.TM.
2 base clear, control) did not inhibit bacterial growth, Paste B
(Nexus.TM. 2 base clear containing 3.0% Irgaguard.RTM. B7000)
reduced the bacterial count by 99.11%, and Paste C (Nexus.TM. 2
clear containing 0.4% Irgaguard.RTM. B5000) reduced the bacterial
count by more than 99.95%.
1TABLE 1 Bacterial Growth Inhibition of Silver-Containing Additives
Against S. mutans (AATCC100 Method) CFU (Colony Forming Units)
Percent 24 hour Reduction Formula Composition Initial contact (%)
Paste A Nexus .TM. Base Clear 210000 550000 No reduction
(increased) Paste B Nexus .TM. Base Clear 180000 1600 99.11% with
3.0% Irgaguard .RTM. B7000 Paste C Nexus .TM. Base Clear 190000
<100 >99.95% with 0.4% Irgaguard .RTM. B5000
Example 2
[0040] Irgaguard.RTM. B7000 was incorporated in the catalyst paste
of a commercial core buildup material (CoreRestore.RTM. 2, Kerr
Corporation, Orange Calif.) at 3%.sup.w/w concentration. The color
stability of the catalyst pastes with and without Irgaguard.RTM.
B7000 was measured initially and then at different time intervals
after the pastes were stored at elevated temperatures (37.degree.
C. and 42.degree. C.). The results are shown in Table 2.
[0041] A CoreRestore.RTM. 2 catalyst paste without Irgaguard.RTM.
B7000 became significantly more yellow (b* value becoming more
positive) and somewhat more green (a* value becoming more negative)
than CoreRestore.RTM. 2 catalyst paste with Irgaguard.RTM.
B7000.
[0042] The overall color change was calculated using following
equation:
.DELTA.E={(L*.sub.1-L*.sub.0).sup.2+(a*.sub.1-a*.sub.0).sup.2+(b*.sub.1-b*-
.sub.0).sup.2}.sup.1/2
[0043] Where L*.sub.0, a*.sub.0, and b*.sub.0 were the initial
color coordinates of freshly prepared material before aging; and
L*.sub.1, a*.sub.1, and b*.sub.1 were the color coordinates after
aging.
2TABLE 2 Effect of B7000 Additive on Color Stability of CoreRestore
.RTM. 2 Catalyst Paste CoreRestore .RTM. 2 with 3% Storage Storage
CoreRestore .RTM. 2 Irgaguard .RTM. B700 Temp. Time L* a* b*
.DELTA.E L* a* b* .DELTA.E Initial 74.84 -1.79 4.41 74.56 -1.72
4.22 37.degree. C. 11 days 74.43 -2.10 6.80 2.44 74.35 -1.81 4.80
0.62 18 days 74.10 -2.18 6.97 2.69 74.43 -1.98 4.91 0.75 25 days
73.49 -2.62 9.60 5.43 73.84 -1.96 5.70 1.66 32 days 73.16 -3.42
12.35 8.28 73.95 -2.09 6.10 2.01 39 days 73.27 -3.67 13.25 9.17
74.22 -2.36 6.85 2.73 42.degree. C. 4 days 74.39 -1.90 5.24 0.95
74.47 -1.80 4.46 0.27 8 days 74.08 -2.14 6.49 2.24 74.46 -1.84 4.77
0.57 11 days 73.76 -2.22 7.42 3.23 74.37 -1.89 5.01 0.83 14 days
73.33 -2.67 9.43 5.32 74.01 -1.93 5.09 1.05
[0044] The color change (.DELTA.E) for the CoreRestore.RTM. 2
catalyst paste with the silver-zinc glass additive (Irgaguard.RTM.
B7000) was much less than that for the CoreRestore.RTM. 2 catalyst
paste without Irgaguard.RTM. B7000. Therefore CoreRestore.RTM. 2
catalyst paste with the silver-zinc glass additive was much more
color stable than CoreRestore.RTM. 2 catalyst paste without the
additive.
Example 3
[0045] Irgaguard.RTM. B7000 was incorporated in the catalyst paste
of a commercial resin cement (NexuS.TM. 2 Kerr Corporation, Orange
Calif.) at 3%.sup.w/w concentration. The color stability of the
pastes with and without Irgaguard.RTM. B7000 was measured initially
and then after aging at 42.degree. C. for twenty-two days.
[0046] The results are shown in Table 3. Nexus.TM. 2 catalyst paste
without Irgaguard.RTM. B7000 became significantly more yellow (b*
value becoming more positive) and somewhat more green (a* value
becoming more negative) than Nexus.TM. 2 catalyst paste with
Irgaguard.RTM. B7000. The color change (.DELTA.E) for the Nexus.TM.
2 catalyst paste with Irgaguard.RTM. B7000 was much less than that
for the Nexus.TM. 2 catalyst paste without Irgaguard.RTM. B7000.
Therefore Nexus.TM. 2 catalyst paste with the silver-zinc glass
additive was much more color stable than Nexus.TM. 2 catalyst paste
without the additive.
3TABLE 3 Color stability of Nexus .TM. 2 Catalyst Pastes Nexus .TM.
2 with 3% Storage Storage Nexus .TM. 2 Irgaguard .RTM. B700 Temp.
Time L* a* b* .DELTA.E L* a* b* .DELTA.E Initial 72.01 -1.88 5.06
71.86 -1.90 4.92 42.degree. C. 22 days 71.07 -3.57 11.05 6.29 71.89
-2.75 7.98 3.18
Example 4
[0047] Irgaguard.RTM. B7000 3%.sup.w/w was introduced into
Nexus.TM. 2 base clear paste. The mechanical properties
(compressive strength, diametral tensile strength, and flexural
strength) were tested according to the procedures mentioned above,
and the specimens were light-cured with a Demetron Optilux 401
curing light (Kerr Corporation, Orange Calif.) from each side. The
results are listed in Table 4.
4TABLE 4 The Effect of B7000 Additive on Mechanical Properties of
Nexus .TM. 2 Base Paste Nexus .TM. 2 with 3% Mechanical Properties
Nexus .TM. 2 Irgaguard .RTM. B7000 Compressive Strength, MPa 374
.+-. 12 395 .+-. 24 Diametral Tensile Strength, MPa 56.6 .+-. 4.6
55.3 .+-. 5.2 Flexural Strength, MPa 156 .+-. 7 154 .+-. 16 There
are no statistically significant differences between the mechanical
properties of Nexus .TM. 2 base clear paste and Nexus .TM. 2 base
clear paste with 3%.sup.w/w Irgaguard .RTM. B7000. Therefore,
incorporating a silver-zinc glass additive into the Nexus .TM. 2
base paste did not adversely affect its mechanical properties.
Example 5
[0048] Irgaguard.RTM. B7000 (3%.sup.w/w) was introduced into a
resin composite filling material, Prodigy.TM. (Kerr Corporation,
Orange Calif.) which is a light-curable single-part paste. The
mechanical properties were tested and the specimens were
light-cured with a Demetron Optilux 401 curing light (Kerr
Corporation, Orange Calif.) for 30 seconds from each side. The
results are shown in Table 5.
5TABLE 5 The Effect of Irgaguard .RTM. B7000 Additive on Mechanical
Properties of Prodigy Prodigy .TM. with 3% Mechanical Properties
Prodigy .TM. Irgaguard .RTM. B7000 Compressive Strength, MPa 418
.+-. 20 405 .+-. 16 Diametral Tensile Strength, MPa 62.1 .+-. 6.9
66.9 .+-. 3.9 Flexural Strength, MPa 138 .+-. 10 140 .+-. 11 There
are no statistically significant differences between the mechanical
properties of Prodigy .TM. and Prodigy .TM. with 3%.sup.w/w
Irgaguard .RTM. B7000. Therefore, incorporating silver-zinc glass
additive into the Prodigy .TM. paste did not adversely affect its
mechanical properties.
[0049] The above examples demonstrated the usefulness of
silver-containing glass or zeolite ceramics in resin-based dental
restorative materials. While imparting excellent antibacterial
properties, they also greatly improved the color stability of the
catalyst paste of any two-part system with no negative effect on
the mechanical properties of the material.
[0050] The silver-containing glass or zeolite ceramic can also be
incorporated into other dental restorative, endodontic,
orthodontic, and prosthetic compositions. The use for the material
incorporating the antibacterial additives can be temporary (last
less than three months) or permanent (last more than three months).
Orthodontic adhesives or cements incorporating silver-containing
glass or zeolite can be especially useful for orthodontic
applications where good oral hygiene may be difficult to maintain
and bacterial growth is more difficult to control. The
antibacterial additives can be incorporated into a single-part
dental restorative material, such as a light-curable material (with
a light-cure initiator), or heat-curable material (with a heat-cure
initiator), or a combination of heat- and light-curable material.
The light-curable material can be a composite filling material, a
cement, a pit/fissure sealant, a base, or a liner. The heat-curable
material can be a prosthetic material such as an inlay, an onlay,
or a crown material that is polymerized extra-orally by heat or a
combination of light and heat, and then adhered to the tooth
structure with an adhesive and/or a cement. The antibacterial
additives can also be incorporated into a two-part dental material
such as a self-curable (with a redox initiator system) or
dual-curable (combination of self-cure and heat-cure, or
combination of light-cure and self-cure) material. Overall any
configurations (such as light-cure versus self-cure or dual-cure;
one-part versus two-part; filling material versus cement, liner, or
adhesive, or endodontic sealing material; composite resin versus
hybrid material such as resin-ionomer or resin-modified
glass-ionomer) can be easily obtained by incorporating different
curing initiators (photo-initiator, heat-cure initiator, redox
initiator, or a combination thereof), filler type (reactive filler
and/or non-reactive filler), and modifying viscosity (varying
filler concentration, and/or use of solvent).
[0051] The above examples are for illustrations only, and should
not be construed to limit the scope of this invention. It should be
understood that the embodiments of the invention shown and
described in the specification are only preferred embodiments of
the inventor who is skilled in the art and are not limiting.
Therefore, various changes, modifications or alterations may be
made or resorted to without departing from the spirit of the
invention and the scope of the following claims.
* * * * *