Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02296227 2000-O1-19
1
Dental materials based on polysiloxanes
The invention relates to dental materials based on
methacrylate-modified polysiloxanes capable of polymerization.
Dental materials based on silanes capable of polymerization
are known. DE 36 10 804 A1 discloses dental resin compositions
which contain siloxane polymers, monomers which are co-
polymerizable with the siloxane polymer, and a polymerization
catalyst. The dental resin compositions are said to have an
improved compressive strength, abrasion resistance and
flexural strength after polymerization.
DE 34 07 087 A1 and WO 92/16183 relate to the use of compounds
based on organically modified silicic acid polycondensates for
coating teeth and tooth-replacement parts . The cured coats are
said to be resistant to the build-up of plaque.
Dental resin compositions based on polymerizable polysiloxanes
are known from DE 41 33 494, which are manufactured by
CA 02296227 2000-O1-19
hydrolytic condensation of one or several silanes of which at
least one is substituted by a 1,4,6-trioxaspiro-[4,4]-nonane
radical or a (meth)acrylate group, the latter preferably
containing a thioether function. The dental resin compositions
are said to show only a small change in volume during curing,
however silanes with orthoester groups are difficult of access
and less storage-stable whereas thioether groups are sensitive
to oxidation.
DE 196 19 046 discloses low-shrinkage polymerizable compounds
based on mercapto- or norboronnene silanes and a reaction
partner for the en-thiolpolymerization. The curing of these
compositions is accompanied by low polymerization shrinkage
and results in products with high mechanical strength which
however also contain thioether groups sensitive to oxidation.
The object of the invention is the provision of dental
materials based on polysiloxanes which can be covalently
incorporated in organic-inorganic composite materials and do
not contain spiro- or thioether groups.
The object is achieved by dental materials which contain at
least one polysiloxane based on one or several silanes
according to the formula (I)
[ (Wq-R6-Z ) P-R3 JmY-RZ-SiXnRls-n Formula ( I )
in which
X stands for a halogen atom, a hydroxyl, alkoxy and/or
acyloxy group;
n is equal to 1 to 3;
R1 stands for an alkyl, alkenyl, aryl, alkylaryl,
arylalkyl group;
CA 02296227 2000-O1-19
-3-
RZ stands for an alkylene group;
R3 stands for a p-times substituted, straight, branched or
cyclic, saturated or unsaturated, aromatic or aliphatic
organic radical with 2 to 40 carbon atoms and optionally
1 to 6 heteroatoms;
R6 stands for a q-times substituted, straight, branched or
cyclic organic radical with 1 to 20 carbon atoms or is
absent;
p is equal to 1 to 6;
q is equal to 1 to 6;
y stands for -NR4-, N or -(C=0)-NH-
m is equal to 2 for Y = N and equal to 1 for Y = -NR'- or
-(C=0)-NH-;
R4 stands for an alkyl or aryl group;
Z stands for 0, S, -(C=0)-0-, -(C=0)-NH-, -0-(C=0)-NH-
or is absent;
W stands for CHZ=CR5- ( C=0 ) -0-; and
RS stands for a hydrogen atom or an alkyl group.
Suitable heteroatoms are phosphorus and preferably oxygen.
In the whole description as well as the claims, alkyl,
acyloxy, alkoxy, alkenyl groups and alkylene groups are
understood to mean radicals which preferably contain 1 to 25
carbon atoms, particularly preferably 1 to 10 carbon atoms and
quite particularly preferably 1 to 4 carbon atoms, and
optionally carry one or several subsituents such as for
example halogen atoms, nitro groups or alkyloxy radicals. Aryl
means radicals, groups or substituents which preferably have
6 to 10 carbon atoms and can be substituted as stated above.
The above definitions are also valid for compound groups such
as for example alkyl aryl and aryl alkyl groups . An alkyl aryl
CA 02296227 2000-O1-19
group thus describes for example an aryl group defined as
above which is substituted by an alkyl group as defined above.
The alkyl, acyloxy, alkoxy, alkenyl groups and alkylene groups
can be straight-chained, branched or cyclic.
Preferred definitions, which can be chosen independently from
each other, for the individual variables, are:
X - a methoxy a_nd/or ethoxy group;
n - 2 or 3;
R1 - a C1 to C3 alkyl group, in particular a methyl
group:
RZ - a C1 to C4 alkylene group;
R3 - a p-times substituted, straight, branched or
cyclic, saturated or unsaturated, aromatic or
aliphatic organic radical with 2 to 10 carbon atoms
and optionally a heteroatom, preferably an oxygen
atom, particularly preferably a C1 to C4 alkenylene
radical or a monocyclic radical with 4 to 10, in
particular 5 to 8 carbon atoms;
R6 - a q-times substituted, straight, branched or
cyclic organic radical with 1 to 4 carbon atoms,
particularly preferably a C1 to C3 alkylene radical;
p - 1 or 2, in particular 1;
q - 1 or 2;
Y - N or -(C=O)-NH-;
Z - -(C=0)-O-; and/or
RS - a hydrogen atom or a methyl group.
Concrete examples of particularly preferred silanes according
to formula (I) are:
' O'
~~O%~ I ~O
I t O ,I
C~~~ o
S ~~~2H5~3
CA 02296227 2000-O1-19
_j_
O~ . ~O
° O
O ~C~a O
S i (OCZH~)3
O O
O I
~O N%'~ ~/O
O
O C H~
~ -~ a O
S i (OC H3),;
O O
0 0
~o i o~ I
C~~3 0
CN3-5~~~2H5)2
O O
O ~Hz ~ O CH~-O
-O i O-CH O I
O-CHZ CCH~s~ CHZ-O
S~(OC~H~~;
O O
0 o i
~o-c
o ~ ~ I ' ~ cH~-o 0
HC-O N
I ~ ~ O-CH
~~--CHZ (CH2~~ CHZ~
CH3-S i (OC,H$~
O
O
0 o I
O O-CH, ' ,CH2-O
HC -O N'~~O-C H
~O-C H
~C rid, ~ C H_-O'~
S i (OC: H~);
CA 02296227 2000-O1-19
-6-
p
4-CHZ O O CH2~ O
p HC-O ~ O-CH
~O-C H~ (C Hz~ 3 C
S 1 (OC H3)3
oc o l oc. o
.o~ ~~! ~ o~
_ ~ o
o
~c ~ ~c .
HN-(C H~);-S i (OC~HS)s ~--(C H2)3-S I (OC~H;)3
O O C~ O
p p
I O \ ~ O
~O O=C
HN-(CHZ)3-St(OC~HS)3 ~(C~J~ SI(OC~H;)3
O O C~ O
Cy~ p
p
D=C
HN-(CH2)s-Si(OC2~~ HN-(CE'~z~3-'SI(OCZf"ts)~
O
O O
C O-O~ I ~~ ~ i
o co 0
0 1
HN-(C H=);-S i {OC ZH~); HN-(CHI);-S i (OC?HS)3
. . ... . ::.. _ . ._.. _.~ ._._. ____._.,._ . =__= ~ _ ~~~;;, _..
__. _ _ ~.. , ._... .,;~:
CA 02296227 2000-O1-19
O
CHI-Q
C~ O~ CHZ-O
I H CO--p-CH O
CHZ-p ~ CH,-O
OC
1 OC
HN-(CH2)s-Si(OC=H5)3 HN-(CH~)3-Si(OC2H5)3 4
O O
O' CHZ--fl - CH~,-p
y-O--~H O O O-CH
I / i
CH~-O ~ O CHZ-O
O=C - '~-CO
1
HN-(CHZ)3'wSi (OC2 H5)3 ~(C ~~--5 I(OC2''~)3
O
CHZ--~
O /O-CH O J
CO CH2-O
O
D=C CO
~1-(CH~~-Si(OC2H~)3 HN- CH -- '
_ ( 2~~ S~(OC~HS)3
CA 02296227 2000-O1-19
_g_
O
CH__.C O
O . O_O_CH
CH -O
, o o~ o _
C
1
HIS--(CHI);-Si(OC~H~~ ~(C~~; _Si(OCZH3);
The silanes of formula (I) are accessible via addition and
condensation reactions known per se, the number of
hydrolyzable groups,_ groups capable of polymerization.,_ and
further functional groups being able to be varied by the
appropriate selection of educts.
Silanes in which Y has the meaning -NR4- or N are for example
accessible by addition of an aminosilane compound to an m-
times unsaturated group R3:
(W Z)p (R3-2mH) + HmY R2 SiX,~R~
3-n
r
. (~ Z) . R3 Y R2 S~X~R~
3-n
Thus e.g., bis[2-(2-methacryloyloxyethoxycarbonyl)-ethyl)-(3-
triethoxysilylpropyl)amine is obtained by reacting 3-amino-
propyltriethoxysilane with 2-acryloyloxyethylmethacrylate:
CA 02296227 2000-O1-19
_g_
.
O~O ~~ f H2N Si(OC2H5)3
O
o r o
O~O N'~O~O
i
O ~CH~~ 3 O
Si OC H
2 5~3
Silanes in which Y is equal to -(C=0)-NH- are accessible for
example by reacting an isocyanatosilane with a carboxylic acid
which contains p radicals W capable of polymerization:
(W . . Z)p R3 COOH + OCN R2 SiX~R~ ~n
< _Cp2 ,
{W Z)p R3 Y R2 , SiX~R~ 3_~
(Y = CO-NHS
CA 02296227 2000-O1-19
-10-
The reaction of 3-isocyanatopropyltriethoxysilane with 2-
methacryloyloxyethyl-hydrogen-succinate results in e.g. 2-
methacryloxyethyl-3-[(3-triethoxysilyl)propylamino-
carbonyl]propionate:
O
pH + OCN Si(OC2H5~
~O
O O _C02
O
- ~ N Si(OC~H;~s
O
O O
Suitable carboxylic acid methacrylates can be obtained by
reacting di- or tetracarboxylic acid mono or dianhydrides with
suitable OH-functionalized compounds capable of polymerization
such as for example 2-hydroxyethylmethacrylate or glycerine
dimethacrylate.
To synthesize silanes in which Y is equal to -(C=0)-NH-, the
synthesis methods known in peptide chemistry, such as a . g. the
DCC method or the mixed anhydrides method, can moreover also
be used to react carboxylic acids with amino-group containing
compounds, for example the reaction of an aminosilane with a
carboxylic acid which contains p radicals W capable of
polymerization:
(W-~p-R~-COOH + H2N-R~SDC~R~3-n
- HZO
(W-~p-R3-Y- RZ,-SiX~R~3-r,
(Y = CO-NH)
CA 02296227 2000-O1-19
-11-
Thus, the reaction of 3-aminopropyltriethoxysilane with 2-
methacryloyloxyethyl-hydrogen-succinate also results in 2-
methacryloxyethyl-3-[(3-triethoxysilyl)propylaminocarbo-
nylJpropionate:
O
p~ OH + H2 Si(OCZH,}3
O v O
O _H20
_ O ~ _
p~0 NH~~Si(OC2H5}3
O O
The silanes (I) are stable compounds and can be processed to
give the polysiloxanes, either alone or together with other
hydrolytically condensable compounds of silicon, aluminium,
zirconium, titanium, boron, tin, vanadium and/or phosphorus.
These additional compounds can be used either as such or
already in pre-condensed form.
Preferred further hydrolytically condensable compounds of
silicon are silanes of the general formula (II)
R'k(Z'Rg)mSiX'4_tk+m> Formula (II)
in which
R' stands for a Ci to C$ alkyl, CZ to CiZ alkenyl- or
C6 to C14 aryl group;
CA 02296227 2000-O1-19
- 12-
R8 stands for a C1 to C8 alkylene, Cz to
Clz alkenylene or C6 to C14 arylene group;
X' stands for a hydrogen or halogen atom or a C1 to
C8 alkoxy group;
Z' stands for a glycidyl, acryl, methacryl, vinyl,
allyl or vinyl ether group;
k is equal to 0, 1, 2 or 3;
m is equal to 0, 1, 2 or 3; and
k+m is equal to 0, 1, 2 or 3.
Preferred definitions, which can be chosen independently from
each other, for the individual variables, are:
R' - a C1 to C3 alkyl, Cz to C5 alkenyl or a phenyl
group;
R$ - a C1 to CS alkylene, Cz to C5 alkenylene or a
phenylene group;
X' - a halogen atom, a methoxy or ethoxy group;
Z' - an acryl or methacryl group;
k - 0 and 1;
m - 0 and 1;
k+m - 0, 1 or 2.
Such silanes are described for example in De 34 07 087 A1.
Particularly preferred silanes of formula (II) are:
CH3-SiCl3, CH3-Si ( OCzHS ) 3, CzHS-SiCl3, CzHS-Si ( OCzHS ) s. CHz=CH-
Si ( OCZHS ) 3, CHz=CH-Si ( OCH3 ) 3, CHz=CH-Si ( OCZH40CH3 ) 3, ( CH3 )
zSiClz,
(CHs)zSl(OCZHS)zr (CzHs)3S1-C1, (CZHs)2S1(OCZHS)zr (CHs)sSl-C1,
( CHgO ) gSl-C3H6NHZ i ( CH30 ) 3S1-C3H6SHZ r
CA 02296227 2000-O1-19
-13-
O
(CH~)3-SI(OCH3)3 CH2-NCH-CH2-O-(CH~3-Si(4CH3)3
Silanes of the general formula (II) or pre-condensed products
derived from them are preferably used in a quantity of 0 to 90
mol-~, particularly preferably 1 to 60 mol-~ and quite
particularly preferably 1 to 40 mol-~ relative to the total
mass of silanes of formulae (I) and (II) or pre-condensed
products derived from them.
Preferred zirconium and titanium compounds are those according
to formula (III)
MeX "yR9~ Formula ( II I )
in which
Me stands for Zr or Ti;
R9 stands for a hydrogen atom, a substituted or
unsubstituted C1 to ClZ alkyl, C1 to C15 alkyl aryl or C6 to
C14 aryl group;
X" stands for a halogen atom, a hydroxyl or C1 to
C8 alkoxy group;
Y ~is equal to 1 to 4;
Z is equal to 0 to 3.
Preferred definitions, which can be chosen independently from
each other, for the individual variables, are:
R9 - a C1 to CS alkyl or a phenyl group;
X" - a halogen atom, a methoxy, ethoxy or propoxy group;
Y = 4;
Z = 0 or 1, in particular 0.
r
CA 02296227 2000-O1-19
- 14-
Particularly preferred zirconium and titanium compounds are
ZrCl4, Zr(OCZHS)4, Zr(OC3H~)4, Zr(OC4H9)4, ZrOClZ, TiCl4,
Tl ( OCZHS ) 4, Tl ( 0C3H~ ) 4 and Tl ( 0C4H9 ) 4 .
The zirconium and titanium compounds of the general formula
(III) or pre-condensed products derived from them are
preferably used in a quantity of 0 to 70 mol-%, particularly
preferably 0 to 50 mol-% or 0 to 30 mol-% and quite
particularly preferably 0 to 20 mol-% relative to the total
mass of compounds of_formulae (I) and (III) or pre-condensed
products derived from them.
Preferred aluminium compounds are those according to formula
( IV)
AlRl°3 Formula ( IV)
in which
R1° stands for a halogen atom, a hydroxyl or C1 to
C8-alkoxy group, preferably for a halogen atom or a C1 to
CS-alkoxy group.
Particularly preferred aluminium compounds are A1(OCH3)3,
Al ( 0CzH5 ) 3, A1 ( 0C3H~ ) 3, Al ( 0C4H9 ) 3 and A1C13 .
The aluminium compounds of the general formula (IV) or pre-
condensed products derived from them are preferably used in a
quantity of 0 to 70 mol-%, particularly preferably 0 to 30
mol-% and quite particularly preferably 0 to 20 mol-% relative
to the total mass of compounds of formulae (I) and (IV) or
pre-condensed products derived from them.
CA 02296227 2000-O1-19
-1~-
In addition, complexed compounds of zirconium, titanium and
aluminium can be used, acids and J3-dicarbonyl compounds being
preferred as complexing agents. Preferred acids are acrylic
and methacrylic acids or other methacrylate carboxylic acids
such as e.g. 2-methacryloyloxyethyl hydrogen succinate or the
1:1-adducts of glycerine dimethacrylate and carboxylic acid
anhydrides, such as e.g. succinic acid or phthalic anhydride.
Preferred ~i-dicarbonyl compounds are acetylacetone,
acetoacetic acid ethyl ester and in particular 2-
acetoacetoxyethyl methacrylate. These complexing agents are
preferably reacted with alkoxy derivates of zirconium,
titanium or aluminium in the molar ratio of l:l.
In addition, boron trihalides, stannic tetrahalides, stannic
tetraalkoxides and/or vanadyl compounds are suitable for co-
condensation with the silanes according to fomula (I).
When using additional hydrolytically condensable compounds,
the proportion of silanes according to formula (I) in the
polysiloxanes is preferably 10 to 99 mol-%, particularly
preferably 40 to 99 mol-%, each relative to the initial
monomer compounds. The proportion of silanes (I) and (II)
together is preferably at least 20 mol-%, particularly
preferably at least 80 mol-%, likewise relative to the initial
monomer compounds.
The manufacture of the polysiloxanes is carried out by
hydrolytic condensation of the above-listed compounds. In the
case of the silanes of the general formulae (I) and (II), the
hydrolyzable groups X are first split off, silanoles, silane
diols and silane triols being obtained which condense to
polysiloxanes with an inorganic network of Si-O-Si units
accompanied by splitting-off of water.
r
CA 02296227 2000-O1-19
-16-
The hydrolytic condensation of the silanes generally takes
place by reacting the silicon compound to be hydrolized,
either directly or dissolved in a suitable solvent, at room
temperature or accompanied by slight cooling, at least with
the quantity of water stoichiometrically required for complete
hydrolysis and stirring the resulting mixture for one or
several hours. Aliphatic alcohols such as for example ethanol
or isopropanol, dialkyl ketones such as acetone or
methylisobutyl ketone, ethers such as for example diethyl
ether or tetrahydrofuran (THF), esters such as for example
ethyl or butyl acetate and mixtures thereof are in particular
suitable as solvents.
The hydrolysis and condensation of the initial mixture
preferably takes place in the presence of a condensation
catalyst, with compounds splitting off protons or hydroxyl
ions, such as organic or inorganic acids or bases, and also
compounds releasing fluoride ions, such as ammonium fluoride
or sodium fluoride, being preferred. Particularly preferred
are volatile acids or bases, in particular hydrochloric acid
or ammonia. During the hydrolysis and condensation, it has
proved worthwhile to adopt sol-gel techniques, as described
for example in C.J. Brinker et al., "Sol-Gel-Science",
Academic Press, Boston, 1990.
If the hydrolytic condensation is carried out in the presence
of zirconium, titanium or aluminium compounds, the water is
preferably added stepwise, the temperature preferably being
kept in the range of approximately 0 to 30°C. It is often
advantageous to add water in the form of hydrous solvents such
as for example aqueous ethanol, or to produce it in situ, for
example by chemical reactions such as esterifications.
CA 02296227 2000-O1-19
-17-
The polysiloxanes obtained can be used directly or after
partial or complete removal of the solvent. It is often
advantageous to replace the solvent used for the hydrolytic
condensation with another solvent. The silanes (I) and in
particular the polysiloxanes show only a low volatility
because of their high molecular weight and therefore can
largely be processed safely. With regard to the mechanical
properties of the polysiloxanes, it is advantageous to perform
the hydrolytic condensation up to a degree condensation of 65
to 95 mol-~, the degree of condensation being able to be
measured by Z9Si-NMR.
The complete curing of the polysiloxanes takes place by the
addition of suitable initiators and optionally further
components capable of polymerization by thermal, photochemical
or redox-induced polymerization. Several curing mechanisms,
e.g. radical and cationic polmerization, can also be used
simultaneously or in successive steps when different groups
capable of polymerization, e.g. (meth)acryl and epoxide
groups, are present.
To initiate the radical polymerization, thermal and/or
photoinitiators are_preferably used.
Preferred initiators for the thermal curing are peroxides such
as for example dibenzoyl peroxide, dilauryl peroxide, tert.-
butylperoctoate and tert.-butylperbenzoate as well as
azobisisobutyroethyl ester, benzpinacol and 2,2-
dimethylbenzpinacol.
Preferred photoinitiators are benzophenone and benzoin as well
as their derivatives, cx-diketones and their derivatives such
as for example 9,10-phenanthrenequinone, diacetyl and 4,4-
CA 02296227 2000-O1-19
- is -
dichlorobenzil. Particularly preferred photoinitiators are
camphorquinone and 2,2-methoxy-2-phenyl-acetophenone and in
particular combinations of o~-diketones with amines as reducing
agents such as for example N-cyanoethyl-N-methylaniline, 4-
(N,N-dimethylamino)-benzoic acid ester,N,N-dimethylaminoethyl
methacrylate, N,N-dimethyl-sym.-xylidine or triethanolamine.
In addition, acylphosphines such as for example 2,4,6-
trimethylbenzoyldiphenyl or bis-(2,6-dichlorobenzoyl)-4-N-
propylphenyl phosphinic oxide, are suitable as
photoinitiators. - _
Diaryliodonium or triarylsulfonium salts such as for example
triphenylsulfoniumhexafluorophosphate and
triphenylsulfoniumhexafluoroantimoniate are particularly
suitable for the dual curing of radically and cationically
polymerizable systems.
Redox initiator combinations such as for example combinations
of benzoyl or lauryl peroxide with N,N-dimethyl-sym.-xylidine
or N,N-dimethyl-p-toluidine are used as initiators for a
polymerization at room temperature.
The --polymerization- of polysiloxanes with 2 or more
(meth)acrylate radicals results in three-dimensional organic
networks, in which the mechanical properties such as for
example strength and flexibility, as well as the physico-
chemical properties of the cured materials such as for example
adhesivity, water absorption and refractive index, can be
varied via the distance between the Si atoms and the
(meth)acrylate radicals capable of polymerization, i.e. via
the length of the spacer group -RZ-Y-R3-Z-R6-, as well as via
the presence of further functional groups, and optimally
matched to the requirements of each application case. The use
CA 02296227 2000-O1-19
-19-
of aliphatic groups as spacers results in relatively flexible,
and the use of aromatic groups relatively rigid products.
The crosslinking density of the cured materials can be set by
the number of (meth)acrylate groups capable of polymerization,
which allows a further influencing of the properties and
possible uses of the polysiloxanes.
If the monomeric silanes contain, in addition, sonically
crosslinkable groups_such as for example epoxide or oxathane
groups, a further increase in the crosslinking density can be
achieved by their simultaneous or subsequent ionic
polymerization.
The polysiloxanes can be used mixed with suitable sonically
and/or radically polymerizable mono- or multifunctional
monomers. Preferred monomers are mono(meth)acrylates, such as
methyl, ethyl, butyl, benzyl, furfuryl or phenyl
(meth)acrylate, multifunctional acrylates and methacrylates
such as for example bisphenol-(A)-di(meth)acrylate, bis-GMA
(an addition product of methacrylic acid and bisphenol-A-
diglycidyl ether), UDMA (an addition product of 2-hydroxyethyl
methacrylate and 2,2,4-hexamethylene diisocyanate), di-, tri-
and tetraethylene glycol-di(meth)acrylate,
decanedioldi(meth)acrylate, trimethylol propane
tri(meth)acrylate, pentaerythritol tetra(meth)acrylate and
butane diol-di(meth)acrylate, 1,10-decanediol-di(meth)acrylate
or 1,12-dodecanediol-di(meth)acrylate.
The polymerizable monomers are preferably used in a quantity
' of 1 to 80 wt-%, particularly preferably 5 to 50 wt-% and
quite particularly preferably 5 to 30 wt-% relative to the
CA 02296227 2000-O1-19
_?
total mass of polymerizable monomer and silanes of the formula
(I) or pre-condensed products derived from them.
The mixtures can moreover contain further additives such as
colorants (pigments and dyes), stabilizers, flavoring agents,
microbiocidal active ingredients, plasticizers and/or UV
absorbers.
Furthermore, to improve the mechanical properties, the
compositions can be filled with organic or inorganic particles
or fibres. Preferred inorganic particulate fillers are
amorphous spherical materials based on mixed oxides of Si02,
Zr02 and/or TiOZ (DE 40 29 230 Al), microfine fillers such as
pyrogenic silicic acid or precipitation silicic acid as well
as macro- (particle size 5 ~m to 200 Vim) or minifillers
(particle size 0.5 to 5 um) such as quartz, glass ceramic or
glass powders with an average particle size of 0.5 um to 5 ~m
as well as X-ray opaque fillers such as ytterbium trifluoride.
In addition, glass fibres, polyamide or carbon fibres can also
be used as fillers.
The compositions are in particular suitable as dental
materials such as adhesives, coating materials, dental cements
and filling materials.
The dental materials according to the invention preferably
contain
(a) 5 to 99.9 wt-~, preferably 5 to 90 wt-~,
particularly preferably 10 to 70 wt-~ polysiloxane; and
(b) 0.1 to 5.0 wt-~, preferably 0.2 to 2.0 wt-$
polymerization initiator; and preferably
(c) 1.0 to 80 wt-~, preferably 5.0 to 50 wt-~
CA 02296227 2000-O1-19
-21-
ionically and/or radically polymerizable monomer; and
preferably
(d) 1.0 to 90 wt-%, preferably 2.0 to 80 wt-
fillers.
The figures given are in each case relative to the total mass
of the dental material.
In the following, the invention is explained in more detail
with reference to embodiments.
Example 1
Synthesis of bis[2-(2-methacryloyloxyethoxycarbonyl)-ethyl]
(3-triethoxysilylpropyl)amine
O O
O
Ow/'~O ~ O
!O
p C H~ 3
C I ')
Si(OCZH,)3
43 g (0.25 mol) 3-aminopropyl triethoxysilane in 40 ml
anhydrous acetonitrile are added dropwise accompanied by ice-
cooling to 92 g (0.5 mol) 2-acryloyloxyethyl methacrylate in
85 ml acetonitrile. After 48 h stirring at room temperature,
the aminosilane has completely reacted. The solvent is
evaporated off accompanied by the introduction of air at
reduced pressure at the rotary evaporator at maximally 46 °C.
132.2 g (98 % yield) of a lightly-coloured clear oily liquid
are obtained.
CA 02296227 2000-O1-19
-22-
1H-NMR (400 MHz, CDC13): 8 = 0.58 (t, 2H, SiCHZ), 1.22 (t, 9H,
CH3),1.52 (m, 2H, CHZ), 1.95 (s, 3H, CH3=C), 2.45 (m, 6H,
NCHZ) , 2. 78 (t, 4H, 0=C-CHz) , 3. 82 (q, 6H, OCHZCH3) , 4.34 (s,
8H, OCHZCHZO) , 5 . 59 and 6 . 16 ( 2s, 4H, =CHZ) ppm.
IR (film): 2974 (s), 1724 (s), 1637 (w), 1320 (m), 1296 (m),
1163 ( s ) and 1078 (m) cm-1.
Example 2
Synthesis of the adduct of 3-aminopropylsilane to 2(1)
acryloyloxy-1(2),3-dimethacryloyloxypropane
15' Step: 2(1)-acryloyloxy-1~2).3-di(methacryloyloxy~pro~ane
O O
I~ o
O~O
//
64 g ( 0 . 7 mol ) acrylic acid chloride in 290 ml ether are added
dropwise to an ice-cooled solution of 135 g (0.6 mol)
glycerine dimethacrylate (GDMA) and 85 g (0.7 mol) collidine
in 290 ml ether. After 16 h stirring at room temperature, the
collidinium hydrochloride precipitate formed is filtered off
and the ether solution washed twice with 100 ml 1N HC1 each
time, twice with 100 ml 10% sodium hydrogen carbonate solution
each time and 3 times with 100 ml water each time. The ether
phase is dried over anhydrous NaZS04, stabilized with 20 mg~
hydroquinone monomethyl ether (MEHQ) and the solvent distilled
off accompanied by introduction of air at the rotary
CA 02296227 2000-O1-19
-23-
evaporator at reduced pressure. 79 g (98 ~ yield) of dark
yellow, clear liquid are obtained.
1H-NMR (400 MHz, CDC13): 8 = 1.94 (s, 6H, CH3), 4.20-4.44 and
5.48 (m, 5H, CHO, CHZO) and 5.60-6.78 (m, 7H, =CHz, CH=CHZ)
ppm.
A detailed comparison of the integral ratios shows that the
reaction is complete and the product contains 13 ~ GDMA.
IR (film): 2960 (m),
and 116 3 { s ) cm-1.
1728 {s), 1638 (s), 1407 {s), 1294 (s)
2n~ Step: Reaction of 3-amino~ropylsilane with 2(1)-
acryloyloxy-1(21,3-difmethacryloyloxy)propane
/S I(OC2H~)3
O O
~O~
_O J OO
O
A solution of 63.3 g (224 mmol) 2(1)-acryloyloxy-1(2),3-
dimethacryloyloxypropane, 24.8 g (111 mmol) 3-
aminopropyltriethoxysilane, 50 mg MEHQ in 200 ml absolute
methanol is stirred for 6 d under argon at 40 °C. The methanol
is removed on the rotary evaporator, accompanied by
introduction of dry air, at 40 °C and at reduced pressure. 79
g (89 % yield) of a dark yellow, clear liquid are obtained.
CA 02296227 2000-O1-19
-24-
1H-NMR (400 MHz, CDC13): 8 - 0.59 (t, 2H, SiCH2), 1.25 (q,
CH3), 1.50-1.52 (m, 2H, CHZ), 1.96 (s, 12H, CH3), 2.42-2.44 (m,
6H, NCHZ), 2.76 (t, 4H, 0=C-CHZ), 3.56 (s, OCH3), 3.80 (t,
OCHZ), 4.19-4.40 and 5.18 (m, lOH, CHO and CHZO) and 5.60 and
6.15 (2s, 8H, =CH2) ppm.
The 1H-NMR-spectrum shows that an ester interchange partially
took place with the solvent methanol at the triethoxysiyl
group during the reaction.
IR (film): 3504 (w), 2954 (m), 1724 (s), 1637 (m), 1453 (m),
1296 (s) and 1162 (s) cm-1.
Examgle 3
Synthesis of 2-methacryloyloxyethyl-3-[(3-triethoxysilyl)
propylaminocarbonyl)propionate
15' Step: 2-methacryloyloxyethyl hydrocten succinate
0
coon
0
0
40 g (0.4 mol) succinic acid anhydride, 52 g (0.4 mol) HEMA
and 80 mg MEHQ in 200 ml dioxane are mixed with 2 drops of
conc. sulphuric acid and heated for 5 hours to 80°C. The
dioxane is largely distilled off at the rotary evaporator with
applied oil pump vacuum ( 1-5 mbar) accompanied by introduction
of air. The product is then~taken up in 100 ml methylene
chloride and washed 3 times with 100 ml water each time and
dried over anhydrous sodium sulphate. After renewed
CA 02296227 2000-O1-19
-2~-
stabilizing with 40 mg MEHQ, the solvent is removed under
reduced pressure and accompanied by introduction of air. 80 g
(87 ~ yield) of a yellow-coloured liquid are obtained.
1H-NMR (400 MHz, CDC13): 8 - 1.93 (s, 3H, CH3), 2.53-2.64 (m,
4H, CHZCHzCOOH) , 4 . 31 ( s, 4H, OCHZCHZO) , 5 . 61 and 6 . 11 ( 2s, 2H
=CHZ) and 10.70 (br, 1H, COOH) ppm.
IR (film): 3400-2400 (br), 2960 (m), 1722 (s), 1698 (s), 1636
(m), 1406 (m) and 1147 (s) cm 1.
2nd Step
2-methacryloylox3~ethyl-3-[J3-triethoxysilyl)propyl-
aminocarbonyl]-propionate
O O
i j
p O ( NN
~'SI~OC~H5~3
O
20 g ( 87 mmol ) 2-methacryloyloxyethyl hydrogen succinate, 21. 5
g (87 mmol) 3-isocyanatopropyl triethoxysilane and 2 drops of
dibutyl tin dioctoate are stirred at room temperature in 50 ml
methylene chloride until no more isocyanate can be detected in
the IR spectrum (approx. 3 days). The reaction solution is
stabilized with 30 mg MEHQ and the solvent distilled off with
introduction of dry air at the rotary evaporator. 33.7 g (90
yield) of a coloured liquid are obtained.
1H-NMR (400 MHz, CDC13): s = 0.65 (t, 2H, CHZSi), 1.23 (t, 9H,
CH3), 1.61-1.62 (m, 2H, CH2), 1.95 (s, 3H, CH3), 2.51-2.67 (m,
4H, CHZCHZCOZ) , 3 . 10-3 . 20 (m, 2H, CHIN) , 3 . 81, (q, 6H, CHzO) ,
4.27 (br, 1H, NH), 4.37 (s, 4H, OCHZCHZO) and 5.45 and 6.14
(2s, 2H, =CHZ) ppm.
CA 02296227 2000-O1-19
-2G-
IR ( film) : 3346 (w) , 2975 (m) ,1724 ( s ) , 1639 (w) , 1297 (m) and
1159 (s) cm-1.
Example 4
Hydrolytic condensation of
bis(methacryloylethoxycarbonylethyl)-[3
(triethoxysilylpropyl)]amine
100 mmol of the silane from example 1 are dissolved in 30 ml
anhydrous ethanol. The pre-hydrolysis of the silane is carried
out by adding 300 mmol of water in the form of a 0.1 N NH4F
solution. After 16 to 20 h stirring at room temperature, the
volatile components are removed under vacuum and a low-
viscosity resin (~ - 1.6 Pas) is formed which, after the
addition of a radical initiator, can be used as a component
for a light-curing coating or a light-curing dental material.
Example 5
Hydrolytic condensation of
bis(methacryloylethoxycarbonylethyl)-[3
(triethoxysilylpropyl)]amine and subsequent silylation
100 mmol of the silane from example 1 are dissolved in 250 ml
EtOH. The hydrolysis of the silane is carried out by the
addition of 300 mmol of water in the form of a 0.1 N NH4F
solution. After 16 to 22 h stirring at room temperature, the
volatile components are removed under vacuum. The viscous
resin formed is dissolved in 80 ml THF and, for silylation of
0
still-present Si-OH groups mixed accompanied by cooling with
100 mmol collidine as a base and 100 mmol
trimethylchlorosilane (TMCS). To complete the reaction, the
CA 02296227 2000-O1-19
-27-
mixture is stirred for 12 to 24 h at room temperature before
the precipitate formed is filtered off. After the removal of
the volatile components under vacuum, a low-viscosity resin (r~
- 4.9 Pas (23 °C)) is obtained which, after the addition of a
radical initiator, can be used as such or as a component for
a light-curing coating or a light-curing dental material.
To measure the mechanical properties, corresponding testpieces
were produced from the resin and cured by illumination (6
minutes ) with a Spectramat dental radiation source ( Vivad_ent ) .
The polymerization shrinkage (~V) was calculated from the
difference of the resin and polymer density measured by gas
pycnometry and the flexural strength (FS) or the flexural-E-
moduus (FEM) measured according to ISO standard 4049 (1988),
each testpiece being dried at 37 °C for 24 h. The results are:
FS - 67 MPa, FEM - 1950 MPa, 4V - -7.3 vol-%. A glass
transition temperature of the polymerisate of T~ = 95 °C was
measured by means of a dynamic-mechanical analysis.
Example 6
Hydrolytic condensation of the adduct of 3-aminopropylsilane
with 2(1)-acryloyloxy-1(2),3-di(methacryloyloxy)propane
100 mmol of the silane from example 2 are dissolved in 300 ml
anhydrous ethanol. The pre-hydrolysis of the silane was
carried out by adding 150 mmol water in the form of a 0.1 N
NH4F solution. After 16 to 20 h of stirring at room
temperature, the volatile components are removed under vacuum
and a low-viscosity resin (r~ - 2.8 Pas) is obtained which,
after the addition of a radical initiator, can be used as a
component for a light-curing coating or a light-curing dental
material.
CA 02296227 2000-O1-19
-ZS-
Example 7
Preparation of a dental cement
A dental cement of the following formulation is prepared on
the basis of the resin from example S obtained after
hydrolytic condensation and subsequent silylation:
Resin from example S: 31.6 wt-~
UDMA: - 7.8 wt-o
Silanized OX-50: 41.4 wt-~
YbF3 : 18 . 7 wt- o
Photoinitiator*) 0.5 wt-
OX-50 = silanized pyrogenic silicic acid (Degussa),
primary particle size 40 nm
YbF3 - ytterbium fluoride (Rhone-Poulenc)
*) mixture of equal proportions of camphorquinone
and N-(2-cyanoethyl)-N-methylaniline
The components are processed to a paste with an Exakt-type
triple roll mill {Exakt Apparatebau) and testpieces are then
manufactured and tested analogously to example 5. The results
are: FS = 62 MPa, FEM = 3260 MPa and ~V = -3.6 vol-~.
