Note: Descriptions are shown in the official language in which they were submitted.
20~8~
The present invention relates to a dental material that is in
the form of a paste, that hardens in the presence of an
initiator to a mass that can be polished to a high lustre,
said dental material consisting of a polymerisable organic
binding agent and a fine-grained filler. The material
contains at least one polymerisable methacrylate and an
optionally silanisable, new type, filler based on functional
polysiloxanes as binding agent. In addition to this,
initiators for starting polymerisation, additional fillers
such as finely-ground glasses, highly dispersed silicic acid
or preformed polymers, pigments and stabilisers can also be
contained in it. Other additives such as softeners or
additives to improve impact strength can also be used.
The term "dental material" includes, for example, filling
materials for use in caries defects or other tooth defects
within the mouth, inlays, crown and bridge materials, blends,
substances for sealing and protective coatings, plastic
strengthening materials for holding inlays or crowns and
bridges, materials used to build up broken teeth, materials
used for prostheses, and the materials used for the
production of false teeth.
Conventional dental substances of the type described above
contain at least one monomer ester of methacrylic acid, but
mostly a mixture of a plurality of such esters. Suitable
monofunctional esters of methacrylic acid are, for example,
methyl methacrylate, ethyl methacrylate, isopropyl
methacrylate, n-hexyl methacrylate, and 2-hydroxyethyl
methacrylate.
Recently, multifunctional esters of methacrylic acid with
high molecular weights have also been used, these being
ethyleneglycoldimethacrylate, butanediol-1,4-dimethacrylate,
triethyleneglycoldimethacrylate, dodecandiol-1,12-
dimethacrylate, decandiol-1,10-dimethacrylate, 2,2-bis-
[p(gamma-methacryloxy-beta-hydroxypropoxy)-phenyl]-propane,
., , . , ~ . :
.
8 ~
the diaduct oE hydroxyethylmethacrylate and
trimethylhexamethylenediisocyanate, the diaduct of
hydroxyethylmethacrylate and isophorondiisocyanate,
trimethylolpropanetrimethacrylate,
pentaerythrittrimethacrylate, pentaerythrittetramethacrylate,
and 2,2-bis[p(beta-hydroxy ethoxy)-phenyl]
propanedimethacrylate (bis-GMA).
The materials used for dental purposes can be hardened in
various ways, depending on the purpose Eor which they are
used. There are both photohardened as well as self-hardened
(autopolymerising) substances used for tooth filling
materials. The photohardened substances contain
photoinitiators such as benzoinalkylether, benzilmonoketales,
acylphosphinoxides, or aliphatic and aromatic 1,2-diketo
compounds such as campherchinon and polymerisation
accelerators such as aliphatic or aromatic tertiary amines
(e.g., N,N-dimethyl-p-toluidin triethanolamine) or organic
phosphites, and harden when irradiated with ultra-violet or
visible light.
As a rule, the self-hardened materials consist of a catalyst
paste and a base paste, of which each contains a component
element of a redox system and which polymerise when the two
components are mixed. The one component of the redox system
is in most instances a peroxide, such as, for example,
dibenzoylperoxide and the other is mostly a tertiary aromatic
amine such as, for example, N,N'-dimethyl-p-toluidine.
Other dental materials such as plastics used for dental
prostheses or plastic substances used for the production of
false teeth can be polymerised by the action of heat. ~ere,
as a rule, peroxides such as dibenzoylperoxide,
dilaurylperoxide or Bis(2,4-dichlor-benzoylperoxide) are used
as initiators.
2~0~1
As a rule, den-t~1 materials also contain pigments which,
added in the appropriate quantities, serve to match the
colour of the dental masses to the various shadings of
natural teeth. Suitable pigments used Eor this purpose are,
for example, iron oxide black, iron oxide red, iron oxide
yellow, iron oxide brown, cadmium yellow and cadmium orange,
zinc oxide and titanium dioxide.
In addition, dental materials contain mostly organic or
inorganic fillers. This is done in order to prevent the
plastic substance shrinking during polymerisation. Pure
monomer methylmethacrylate shrinks by approximately 20%-
volume on polymerisation, for example. This shrinkage can be
reduced to approximately 5-7~ by the addition of
approximately 60 parts-weight of solid pearl polymeride (DE-
PS 24 03 211).
Other organic fillers are obtained in that one produces apolymerisate that essentially consists of esters of
methacrylic acid and is either not cross-bonded or cross-
bonded. Optionally, this polymeriside contains surface-
treated fillers. It is produced as a polymerisate and can beadded to the dental material in this form; in contrast to
this, it can be produced by substance polymerisation in
compact form, so that prior to incorporation in the dental
material it must first be ground to form a so-called splinter
polymerisate.
In addition to the previously discussed pearl and splinter
polymerisates, preformed polymerisates that are frequently
used are homopolymerisates of th~ methacrylic acid
methylesters or, preferably not cross-bonded, copolymerisates
of the methacrylic acid methylester with a small fraction of
esters of methacrylic acid or acrylic acid with 2 to 12 C
atoms in the alcohol component, more appropriately in the
form of a pearl polymerisate. Other suitable polymerisates
, ' , ' ' , . ,
.' :.
20~081
are uncross-bonded products based on polyurethanes,
polycarbonates, polyesters and polyethers.
Inorganic fillers are, for example, ground glasses or quartz
with mean particle sizes between approximately 1 and 10 ~m as
well as highly dispersed SiO2 with a mean particle size
between approximately lo and ~oO nm.
I'he glasses are preferably aluminum silicate glasses that can
be doped with barium, strontium, or rare earths (DE-PS 24 58
380).
With regard to the finely ground quartz or the finely ground
glasses, as well as with regard to the highly dispersed sio2,
it should be noted that, as a rule, the inorganic filler is
silanised prior to being mixed with the monomers so as to
enhance the bond to the organic matrix. To this end, the
inorganic fillers are coated with silane coupling agents that
in most instances have a polymerisable double bond for
reaction with the monomer esters of the methacrylic acid.
Suitable silane coupling agents are, for example,
vinyltrichlorsilane, tris-(2-methoxyethoxy)-vinylsilane,
tris-(acetoxy)-vinylsilane and 3-methacryloyloxy-
propyltrimethoxysilane.
The newly used monomers, discussed above, which are of high
molecular weight, also bring about a reduction of
polymerisation shrinkage. Now, the above-described inert
inorganic finely-ground glasses or organic fillers or
mixtures of these are added to these monomers up to
approximately 85%-wt, whereby a further reduction of the
shrinkage to approximately 1%-vol can be achieved.
The inorganic fillers not only bring about a reduction of
polymerisation shrinkage, but also effect a considerable
strengthening of the organic polymer structure.
20150~1
This strengthening can be plainly seen in an improvement of
the mechanical properties, as well as in an increase of the
resistance to wear (R. Janda, Quintessenz ~Quintessence), 39,
1067, 1243, 1393 (1988). Good mechanical properties and a
high level of resistance to wear are important requirements
that must be possessed by a dental mass that is intended to
provide a permanent replacement for the hard substance in a
tooth.
In addition to satisfying the requirement for strengthening
properties, the fillers must also be able to satisfy other
material parameters. One important parameter in this
connection is the degree to which it can be polished. The
capability of being polished to a high lustre is of
considerable importance for filling materials and crown and
bridge materials for at least two reasons:
- For esthetic reasons, a highly lusterous and completely
homogenous surface is demanded of filling material so that
the filling can no longer be distinguished from the
surrounding, absolutely smooth and natural tooth material.
In addition, this high-lustre filling surface must retain its
character over the long term.
- An extremely smooth surface for the filling is also
important in order that plaque or staining media can find no
mechanical anchoring points.
Now, however, it has been shown that the above-described
finely-ground quartz or glass fillers have good strengthening
properties although they do not meet the requirements for
polishability. For this reason, attempts have been made to
grind these inorganic fillers more finely in order to obtain
a more homogenous surface. However, limits are imposed on
the physical grinding methods used, so that average grain
sizes of smaller than 1 micrometre are extremely difficult to
obtain.
20~08:~
When one used highly dispersed silicic acid (mean particle
size 10-400 nm) as a filler in clental substances (DE-PS 2~ 03
211), it was shown, most surprisingly, that a considerable
improvement in polishability could be achieved by using these
fillers. A disadvantage of the highly dispersed silicic
acid is its marked thickening effect, so that today, as a
rule, it is not possible to achieve filling levels above 52%-
wt, unless one is satisfied with inade~uate processing and
machining characteristics.
Furthermore, materials filled with highly dispersed silicic
acid exhibit greatly reduced strength and hardness compared
to those Eilled with quartz or finely-ground glasses.
It is the task of the present invention to describe a new
light, heat, or self-hardened dental materials produced from
a polymerisable organic binding agent and a finely-divided
filler that can, on the one hand, be polished to a high
lustre and thereby satisfy the esthetic demands imposed on
dental material, and on the other, which have improved
physical properties compared to the polishable dental
materials that represent the present state of the art.
Accordingly the invention provides a new paste-form,
hardening dental material that hardens in the presence of an
initiator and can be polished to a hiyh lustre and which is
produced from a polymerisable organic binding agent and a
finely-divided filler has been developed, this c`ontaining an
organopolysiloxane as the filler, this being composed of
units of the formula
-0-Si-0
2 ~
and units of ~he formula
R1
I
-o-si-o-
I (II)
wherein R1 stands for a linear or branched alkyl group with
1-6 C atoms that is connected to an acrylate or methacrylate
radical/ or for a simple olefin unsaturated, preferably end-
position unsaturated linear, optionally branched, hydrocarbon
radical with 2-8 C atoms, or for a cyclic, simply olefin
unsaturated hydrocarbon radical with 5-8 C atoms, or for a
linear, optionally branched alkyl group with 1-8 C atoms, a
phenyl group, a cycloalkylene group with 5-8 C atoms, or an
alkylaryl group, and/or units of the formula
R2
-0-l i-o- (III)
R 2
.
in which R2 stands for a methyl, ethyl, or phenyl group, and
the free valencies of the oxygen atoms bonded to the silicon
atoms are saturated in the units (I), (II), and (III) as in
the silicic acid structures by a silicon atom of an equal or
different unit, the ratio of the silicon atoms from the units
of formula ~I) to the sum of the silicon atoms of the units
(II) and (III) amounting to.3:1 to 100:1.
The units of formula (I) to (III) can naturally exist in
various forms that differ from each other, i.e., they can be
in the form of a statistical copolycondensate or in the form
of a block copolycondensate, or in the form of a so-called
mixed copolycondensate. According to the present invention,
.,
,, .:
'
201~081
relative to the units of formula (I) to (III), the fillers of
the new dental material can be present in each of the above
forms and in mixtures thereof.
This means, that in the case of a purely statistical
copolycondensate, that contains units of formula (I), (II),
and/or (III), a purely statistical distribution of the
components corresponding to the moLecular ratio of the
starting products is formed.
In the case of a so-called block-copolycondensate, there is a
formation of blocks of equal units of formula (I) and (II)
and/or (III). Finally, a so-called mixed copolycond~nsate
has both the structure of a statistical copolycondensate and
of a block-copolycondensate as well.
The fillers according to the present invention are used in
dental substances in a quantity of 20 to 90%-wt, and
preferably 50 to 85%-wt. The unsaturated organic radical
that may exist on the units of formula (II) can serve
primarily to provide for a more solid bonding of the
polysiloxane filler to the polymer matrix that is
subsequently produced from the polymerisable organic binding
agent.
For this reason, organic radicals Rl, in which a double bond
is easily accessible sterically, are particularly suitable.
This applies in particular for the group
O CH3
Il I
- 1 CH2 ) 3-o-C-C=CH2
because its particularly easily obtained polymerisa~ility is
known and, in addition, in the polymer matrix in which the
2Dl~
filler is to be incorporated this i5, as a rule, a
methacrylate system, both for linear hydrocarbon radicals
with an end position double bond, such as, for example, the
vinyl-butenyl- or octenyl radical. But cyclic hydrocarbon
radicals with polymerisable double bonds are also suitable.
In many cases, Rl can be one of the double-bond free organic
radicals that are also cited under formula (II).
A particularly advantageous composition of the filler, which
is distinguished by simple realization and primarily by the
technical availability of the starting materials, makes
provision for the fact that an organopolysiloxane is used as
a ~iller, this consisting only of the units of formula (I)
and the special units of formula (II),
o O CH3
O-Si- ~ CH2 ) 3-o-C-C=CH2
the molecular ratio of the units of formula (I) to the units
of (II) amounting to 3:1 to 100:1. A filler of this type is
distinguished by the fact that in order to be introduced into
the methacrylate matrix, it is in principle no longer
silanized, i.e., it has to be treated with a methacrylsilane,
after which these methacryl groups are already present in the
filler in a homogenously distributed state.
25 However, this does not preclude the fact that in an
individual case, with regard to further hydrophobising with
additional strengthening of the bonding between the
organopolysiloxane filler and the organic polymsr matrix,
additional silanisation of the filler will be undertaken.
2 ~ 8 ~
Most surprisingly, when the invention was being prepared, it
was found that very good mechanical properties and
polishability of the dental material can also be achieved if
the organosiloxane filler that is used containes no
unsaturated, but only saturated ~1 radicals.
This applies both to the filler, the units of formula (I),
(II) and (III), and for such fillers that contain only units
of formula (I) and (II). Such organopolysiloxane fillers
that are not double-bond functional should be treated with a
suitable organosilane compound, preferably 3-methacryloyloxy-
propyltrimethoxy- or 3-methacryloyloxypropyltriethoxysilane,
before being introduced into the organic polymer matrix.
The same thing applies to a filler composition that is
advantageous because of the particularly easy availability of
the starting materials, this composition forseeing building
up the polysiloxane from units of formula (I) and the special
units of formula (III),
CH3
-o-si-o
. I
,, CH3
the molecular ratio of the units according to formula (I) to
the units of formula (III) amounting to 3:1 to 100:1.
The monomer building blocks of the fillers according to the
present invention are compounds that are known in principle,
for example Si(OC2Hs)4 as a monomer component for one unit of
formula (II) and a compound
O CH3
(H3C0)3Si-tCH2~3-O-C-C=CH2
(H3Co)3Si-CH2CH2CH3
-- 10 ~
20150~1
as a monomer building block for units of formula (II) and a
compound (H3C)2Si(oC2H5)2 as a monomer building block for
units of formula (III).
The composition of the dental substances according to the
present invention that can be built up therefrom can be
described, for example, by formulas for a particular polymer
unit such as
CH3
2 H2 C 1~ 0-(CH2)35io3l2- ~CH3)2sio2/
o
23 7 3 / 2 I H5 C2 ~ 2 Si2 t 2
50 SiO2~H ~C)zSiO2/2
l H3
30 SiO2 CH2:C-C-o-(CH2)3Sio3~2
o
A typical acid catalyst is, for example, hydrochloric acid or
acetic acid, whereas, for example, in addition to ammonia,
amines represent a typical base catalyst.
With regard to physical properties, fillers of a composition
according to the present invention are particularly well
suited for use in the dental materials according`to the
present invention if they have a specific weight per unit
area of approximately 0 to 200 m2/g, preferably approximately
0 to 100 m2/g, and a particle size of 0.01 ~m, preferably 0.1
~m to 30 ~m.
The fiilers contained in the dental material according to the
present invention can be obtained by various methods. One of
these foresees that an alkoxysilane of the general formula
-- 11 --
. . .
.. . ..
~5~
si(~R3~ (IV)
wherein R3 stands for a linear or branched alkyl group with 1
to 5 C atoms, and an alkoxysilane of tha general formula
R1 - Si(oR3)3 (V)
in which R1 is of the same value as in formula (II) and/or an
alkoxysilane of the general formula
~R2)2Si~oR3)2 (VI)
in which R2 is the same value as in formula (III~, is
dissolved in a largely water miscible solvent which, however,
dissolves the sil.anes of formula (IV), (V) and (VI); then a
quantity of water that is at least sufficient for complete
hydrolysis and condensation is added during stirring; the
reaction mixture is then precondensed during continued
stirring at a specific temperature in the range from room
temperature to 200C, the solids that are forming are
stirred, optionally with the addition of further solvent or
water for a further 1 hour to 6 hours at 60C to 200C, at
normal pressure or at a pressure that corresponds to the sum
of the partial pressures at the particular temperature, and
then the polysiloxane that has been formad if processed,
optionally after changing the medium and/or pH value for 4
hours to 5 days at 100C to ~50C in the liquid phase; then,
using the customary techniques, it is separated off from the
liquid phase, and the polysiloxane is optionally washed,
dried at room temperature to 200C, optionally in an
atmosphere of protective gas or in a vacuum, and then,
optionally, this is tempered for 1 to 100 hours at
temperatures from 150C to 250C in an atmosphere of
protective gas or in a vacuum; one then optionally grinds
and/or grades this; when this is done one processes the
organopolysiloxane that has been separated off from the
liquid phase and optionally washed prior to or after one of
- 12 -
2~1~081
the stages of drying, tempering, grinding, grading, in water,
a water/alcohol mixture or in pure alcohol, in the presence
of an acid or base catalyst, preferably in the presence of
ammonia, for a period varying from 1 hour to 5 days at
temperatures from 60C to 250C at a pressure that
corresponds to the sum of the partial pressures at the
particular temperature.
The advantageous application characteristics of the new
fillers are attributable to the acid or alkyline temperature
treatment prior to or after drying or in a processing stage
that is optionally still applied, since above all else a
consolidation of the polymer structure is achieved by this.
In principle, in place of the alkoxy compounds, the
corresponding halogenide or phenoxy compounds can be used as
starting materials for the process, although their use offers
no advantages but can cause difficulties, for example in the
case of the chlorides, because of the hydrochloric acid that
is liberated during hydrolysis.
Hydrolysis of the monomers must be carried out in a largely
water miscible solvent that, however, dissolves the starting
materials. It is preferred that alcohols are used that
corresponds to the alkoxy groupings on the monomer starting
substances.
Especially suitable are methanol, ethanol, n- ana i-propanol,
n- and i-butanol and n-pentanol. Mixtures of such alcohols
can be used as solvents during the hydrolysis.
of course, in place of alcohols, one can also use other polar
solvents that are largely water miscible, although this is
not as useful for reasons of process technology because of
the solvent mixture that is formed with the hydrolytically
separated alcohol.
- 13 -
2~50~1
It is preferred that one carries out the hydrolysis with an
excess of water beyond the stoichiometric required quantity.
The quantity of water that is required for hydrolysis depends
on the speed of hydrolysis of the monomers used in each case,
such that more rapid hydrolysis takes place as the quantity
of water increases, although an upper limit can be set by
separation and formation of a two-phase system that occurs.
As a matter of principle, hydrolysis in a homogenous solution
is to be preferred.
Because of the above aspects, in practice, the maximum
quantity of water by weight is used as is used in total with
regard to the silane monomers. (redo)
The polycondensation can be carried out at di~ferent
temperatures. Because of the fact that polycondensation
takes place quickest at higher temperatures, it is preferred
that this be done at reflux temperature or just below this.
In principle, hydrolysis and polycondensation can be carried
out at still higher temperatures than reflux temperature,
i.e., under pressure.
The reaction mixture can solidify to a solid mass during
polycondensation. For this reason, it is appropriate to add
a suitable quantity of solvent or water in order to thin it.
When this is done, the solvent will, as a rule, be the same
as was used during the hydrolysis of the silanes; i.e., a low
alcohol with 1 to 5 C atoms is preferred.
Of course, water can be used for the thinning as an
alternative to thinning with a solvent. Whichever is used in
an individual case will depend on which physical properties
the copolycondensate that is produced is to have. Depending
on circumstances, one of the processing stages such as
washing, drying, tempering, grinding and grading can be
- 14 -
2~ns~
omitted or else the sequence can be carried out in a
different order.
Separation of the solid that is formed can be effected by
available techniques such as filtering, decanting,
centrifuging, or by distilling off the liquid phase. Washing
of the solid that is formed using the solvent used during
precipitation or with water is preferred.
The dried or tempered product can be ground in various
apparatuses and graded into various grain sizes. Depending
on circumstances, one or the other of the stages such as
washing, drying, tempering, grinding and yrading can be
eliminated, or they can be carried out in a different
sequence.
Grading can, for example, be carried out on a product that i5
moist or, optionally, previously dried or tempered.
The duration of the hydrolysis will depend on the amenability
of the starting material to hydrolysis and on the
temperature. The rate of hydrolysis depends, in particular,
on the siiicon-bonded alkoxy groups, the methoxy group
hydrolysing the most rapidly, with the process slowing down
as the chain length increases or with increasing branching.
Hydrolysis and polycondensation can be accelerated by the
addition of organic or inorganic bases such as, for example,
ammonia or amines, or organic or inorganic acids, such as,
for example, hydrochloric acid, or of conventional
condensation catal~sts such as, for example,
dibutylstannousdiacetate.
In order to compensate for the varied hydrolysis and
polycondensation behaviour of the monomer components of a
statistical copolycondensate, according to one production
variant, the monomer components of formula (IV), (V) and/or
(VI) can be precondensed. To this end, these monomer
- 15 -
2~0~
components are precondensed wi-thout or with the use of a
solvent that dissolves the starting substances, linear or
branched alcohols with 1 to 5 C atoms that correspond to the
alkoxy groups being preferred, in the presence of a quantity
of water that is not sufficient for complete hydrolysis,
preferably 1 to loo mol-~ of the quantity required, for a
period of 5 minutes to up to 5 days at room temperature to
200C.
In order to enhance this precondensation effect, an acid or
lo base condensation catalyst can be added. Examples of
preferred catalysts are hydrochloric acid, acetic acid,
ammonia, caustic soda, or caustic potash, that are used in
gas form or dissolved in water or in an organic solvent.
After successful precondensation, complete hydrolysis and
polycondensation, optionally after the addition of extra
water and optionally after the addition of additional
solvent, is carried out as described.
According to one other method, so-called block
copolycondensates are obtained, in which a formation of
blocks of equal units of formula (I) and ~ and/or (III)
are present. This process provides for the fact that one
precondenses the monomer components according to formula
(IV), (V) and/or (VI) independently of each other, without or
with the use of a solvent that dissolves the starting
substances, the linear or branched alcohols with`l to 5 C
atoms that correspond to the alkoxy groups being preferred,
in the presence of a quantity of water that is insufficient
for complete hydrolysis, preferably of 1 to 100 mol-~ of the
quantity required for this purpose, for a period of time that
varies from 5 minutes to 5 days at room temperature to 200C,
next combines the condensates so obtained, and then
optionally carries out the hydrolysis and polycondensation as
described, optionally after the addition of extra solvent.
- 16 -
2 1~ 8 3L
Of course, one of the above-described condensation catalysts
can be used in this production variant according to the
present invention.
According to another method, so-called mixed
copolycondensates are obtained in which in part there is
formation of blocks of the same units as in formula ~I) and
(II) and/or (III) in which, however, always at least one
monomer component is not precondensed and at least one
monomer component is precondensed.
This process provides for the fact that of the monomer
components of formula (IV), (V), and/or (VI) one precondenses
at least one monomer but at most two monomers independently
of each other, without or with the use of a solvent that
dissolves the starting substances, linear or branched
alcohols with 1 to 5 C atoms, preferably corresponding to the
alkoxy groups being preferred, in the presence of a quantity
of water that is insufficient for complete hydrolysis,
prefarably from l to 100 mol-% of the quantity required for
this purpose, over a period of 5 minutes to up to 5 days at
room temperature to 200C, and then combines the
precondensates so obtained and at least one not precondensed
component with each other and then, optionally after the
addition of extra water and optionally after the addition of
extra solvent, carries out complete hydrolysis and
polycondensation as described heretofore.
The use of an acid or base condensation catalyst and/or one
that contains metal for precondensation is also possible in
this production variant and the further processing of the
polycondensate so formed is set up in the same way as in the
other production method described above.
The quantity of water that is used during precondensation
will depend on which degree of oligomerisation, i.e., which
block size, is to be achieved. When more water is used for
- 17 -
~0~081
precondensation and/or longer precondensation times are used,
nat~lrally, fundamentally greater units will result than when
less water and/or shorter reaction times are used. As has
already been described the duration of the precondensation
depends generally on the amenability of the monomer
components to hydrolysis, and the temperature.
The filler materials for the new dental materials are
distinguished in particular on the basis of the quantitative
hydrolysis and condensation yield and element analysis. From
the purely visual point of view there is no difference
between the copolycondensates obtained by means of the
various production processes. Depending on treatment, the
fillers according to the present invention have surfaces of
approximately 0 to 200 m2/g~ The desired particle size
diameter of 0.01 ~m to 100 ~m can be adjusted without any
problem by the use of existing grinding techniques.
A further object of the present invention is the use of the
dental material according to the preceding demands for the
production of tooth fillings, inlays, tooth sealing, overlays
to protect the surface of the teeth, crowns, blends, bridges,
dental prostheses, artificial teeth, and adhesives for
securing in-lays, crowns and bridges as well as for building
up broken teeth.
The present invention is explained in greater detail below on
the basis of embodiments.
I. Production of the fillers to be used according to the
present invention:
~L
1,465.2 g (7.03 Mol) Si(OC2Hs)4 and 34.8 g (0.234 Mol)
(CH3)2Si(oC2H5)2 were dissolved in 750 ml ethanol. The
solution was heated to refluxing temperature when 525 ml of
- 18 -
2 ~
10% aqueous ammonia solution were added. Stirring was first
carried out for one-half hour during refluxing and then the
- solid that was formed was thinned with 750 ml water. After a
further 2 hours of stirring during refluxing the suspension
was cooled to room temperature and the white solid that had
been formed was filtered off from the liquid phase and washed
with a total o~ 500 ml of water. 700 ml of 2% NH3 solution
' was added to the solid and it was then moved into an
autoclave. After 24 hours of temperature processing of the
autoclave contents at 150C, the solid was dried for 24 hours
at 120C in a drying cabinet in an atmosphere of nitrogen and
then ground for 24 hours in a ball mill.
437.2 g (99.4% of the theoretical yield) of a dental filler,
consisting of polymer units of the formula
(CH3)2siO2/2~3osio2 was obtained.
Specific wei~ht per surface unit: 22 m2/g
Analysis: % C % H % ~i
Theoretical 1.28 0.32 46.4
Found 1.12 0.40 45.6
Example 2
1,456.5 g (6.99 Mol) Si(oC2H5)4 and 43.5 (0.175 Mol)
methacryloyloxypropyltrimethoxysilane were combined in 750 ml
of ethanol. The solution was heated in a 6-l triple neck
flask with KPG stirrer and reflux cooler during stirring at
reflux temperature. 500 ml 5% NH3 solution was mixed in at
boiling temperature. After approximately one-half hour of
stirring during refluxing the white solid that formed was
thinned with 750 ml of water. Stirring was continued for a
further 5 hours during refluxing and then the suspension was
cooled to room temperature and the solid filtered off from
-- 19 --
2 0 ~
the liquid phase. 500 ml of 5~ ammonia solution was mixed
with the solid and this was then moved into an autoclave.
After 48 hours of stirring of the autoclave contents at 130DC
the solid was washed until it was free of ammonia and then
dried for 24 hours at 100C in an atmosphere of nitrogen and
finally ground for 12 hours in a ball mill. 450 g (99.6% of
the theoretical yield) of a dental filler consisting of units
of formula Cll
2 11 2)3 SiO3~2 40SiO2
o
were obtained.
Specific wei~ht per surface unit: 23 m2/g
Analysis: % C % H % Si
Theoretical 3.26 0.43 44.6
Found 3.12 0.34 44.0
15 Example 3
1,431-8 g (6-87 Mol) Si(oc2Hs)4~ 42.7 g (0.172 Mol)
methacryloyloxypropyltrimethoxysilane and 25.5 g
(CH3)2Si(oC2H5)2 were combined in 750 ml of methanol. The
solution was heated to reflux temperature when 450 ml of 5%
ammonia solution were added to it. After a further
processing as in Example 2, 450 g (98.6% of the theoretical
yield) of a dental filler, consisting of units of the formula
C H 3
CH2-C_c-o-~cH2~3-sio3l2- ~C~3125iO2/2 ~SiQ2
were obtained. 0
Specific weight per surface unit: 32 m2/g
- 20 -
- .
2~1~081
Analysis: % C % H % Si
Theoretical 4.07 0.64 44.4
Found 3.82 0.59 43.4
Example 4
722.9 g (3.47 Mol) Si(oC2~5)4, 14.3 g (0.0867 Mol) n-C3H7-
Si(OCH3)3 and 12.9 g (0.0867 Mol) (CH3)2si(OC2H5)2 were
dissolved in 375 ml of ethanol. The solution was heated to
reflux temperature and 200 ml ln-HCl solution were added to
it. The solid, which formed after 1 hour, was diluted with
400 ml of methanol and then stirred for an additional half
hour during refluxing. The solid that was next filtered off
had 500 ml of 10% ammonia solution added to it and was
stirred for 15 hours in an autoclave at 150C. After
additional processing as in Example 2, 220.0 g (98.6% of the
theoretical yield) of a dental filler, consisting of units of
the formula
3H7Sio3/2 ~cH3)2sio2/2 . ~0 Si02
were obtained.
Specific weiqht per surface unit: 56 m2/g
Analysis: % C % H~ % Si
Theoretical 2.3 0.51 45O9
Found 2.1 0.40 44.8
Example 5
727.8 g (3.49 Mol) Si(oC2~5)4 and 22.2 g (0.1165 Mol) CH2=CH
Si(oC2H5)3 were combined with each other. The mixture was
- 21 -
. . . : ......... : . ,
.
~ ..... ' " ' ' ,
2 ~
stirred with 300 ml Oe o. 1 n acetic acid solution for 3 hours
at 80C.
After this precondensation, ~00 ml of ethanol and 200 ml of
water were added to the mixture and it was then stirred agai
during refluxing. The solid that was formed after 2 hours of
refluxing was filtered off and aEter being washed with a
total of 1-1 of water was subjected to further processing as
in Example 4. 216.0 g (98.5% of the theoretical yield) of a
dental filler, consisting of units of the formula
CH2=CH-sio3l2 30Sio
were obtained.
S~ecific weiqht per surface unit: 22 m2/g
Analysis: % C % H % Si
Theoretical 1.28 0.16 46.3
Found 1.17 0.20 45.8
Example 6
727.8 g (3.49 Mol) Si(oC2H5)4 were added to 200 ml of 1%
aqueous ammonia solution and stirred for 2 hours at 100C.
Simultaneously, 19.0 g (0.07 Mol) (C6H6)2si(0C2H6)2 were
added to 5 ml of ethanol and 0.5 ml of 2% aqueous ammonia
solution and stirred for 10 hours at 100C. Next, the
precondensates were combined and 500 ml of ethanol and 150 ml
of 2% aqueous NH3 solution were added to it and it was then
stirred for a further 3 hours during refluxing. The solid
that formed was filtered off and after being washed with 500
ml of ethanol was subjected to further processing as in
Example 4.
- 22 -
.
., . ~ .
' ~ ' .
~ ~ ' - . ,
2 0 ~
After a subsequent 24 hour tempering at 150C in a nitrogen
atmosphere, 220.0 g (98.1% of the theoretical yield) of a
dental filler consisting of units of the formula
( C6~15) 2Si2/2 50sio2
were obtained.
Specific weiqht per surface unit: 31 m2/g
Analysis: % C % H % Si
Theoretical 4.50 0.31 44.7
Found 4.40 0.26 43.9
Example 7
17.3 g (0.087 Mol) (C6H5)Si(oCH3)3 had 0.2 ml of 2% methanol
NH3 solution added to it and initially stirred for 5 hours at
60C. Then the precondensate was combined with 727.8 g (3.49
Mol) Si(oC2H5)4. After further processing as in Example 7,
216.3 g (98.2% of the theoretical yield) of a dental filler,
consisting of units of the formula
~ 5 3~2 /OSiOz
were obtained.
Specific weiqht per surface unit: 48 m2/g
Analysis: % C % H % Si
: Theoretical 2.85 0.20 45.5
Found 2.95 0.31 45.8
.
, :., ' :
,
''' , : ~
~0~ 81
II. Production of the dental substance according ~o the
present invention
After production of the dental substances according to the
present invention, the fillers from Examples no. 1 to no. 5
were ground down to a mean grain size o~ approximately 3 to 7
~m in a ball mill. The fillers were then silanised with 3-
methacryloyloxypropyltrimethoxysilane, using the usual
process.
The fillers were introduced in quantities from approximately
70 to 73% (m/m) into a monomer matrix as is customarily used
for dental plastics. Initiators were added and the mass was
kneaded to form a homogenous paste.
A number of physical characteristics were determined on
hardened test bodies produced from the various pastes and
compared with commercially available products and laboratory
comparison samples (Table I).
Checking and assessing polishability
Test bodiés, 15 mm diameter and 3 mm thick, were produced
from all the materials. The surfaces of all the test bodies
were first abraded evenly with fine abrasive paper (600
grit). Then they were polished with the finest possible
grade of aluminum oxide (mean grain size 0.0~ ~m) on à cotton
cloth.
The polishability was assessed visually and noted by means of
a point scale ranging from 1 to 5, where l = matt and 5 = a
high lustre.
Examples for the dental ~ubstances according to the pres~nt
invention
- 24 -
. ~ :
':
20~508~
1. Heat hardened dental substances according to the present
invention
Production of the test bodies from the heat hardened dental
substances according to the present invention was effected
such that the masses were pressed into appropriate test-body
moulds and then hardened in a water bath at a pressure of 6
atmospheres at 90~C for 30 minutes.
The following abbreviations are used in the examples which
follow:
Bis-GMA: 2,2-Bis-[p-(~-methacryloyloxy-~-
hydroxypropoxy)-phenyl]-propane
TEDMA: Triethylenglykoldimethacrylate
Example 9 (data in parts by weight):
73.0 filler as in Example 1
18.2 Bis-GMA
8.5 TEDMA
0.3 dibenzoylperoxide
Example 10 (data in parts by weight):
70.0 filler as in Example 2
20.3 Bis-GMA
9.4 TEDMA
0.3 dibenzoylperoxide
- 25 -
201~i0~
Example ll tdata in parts by weight):
70.0 filler as in Example 3
20.3 Bis-GMA
9.4 TEDMA
5 0.3 dibenzoylperoxide
Example 12 (data in parts by weight):
71.0 filler as in Example 4
19.6 BiS-GMA
9.1 TEDMA
0.3 dibenzoylpereoxide
Example 13 (data in parts by`weight~:
73.0 filler as in Example 5
18.2 Bis-GMA
8.5 TEDMA
0.3 dibenzoylperoxide
2. Photohardened dental substances according to the present
invention
The photohardened dental masses according to the present
invention consists of a white paste that is hardened by
exposure to a dental halogen lamp (Translux, Kulzer). The
radiation time amounts to 100 seconds.
- 26 -
,
- ' ~' , '~ ' '' :
201~8~
Example 14 (data in parts by weight):
70.0 filler as in Example 2
19.0 Bis-GMA
8.7 TEDMA
0.2 Campherchinon
0.1 N,N-Dimethyl-p-toluidine
Commercial products, with which the dental substance
according to the present invention as set out in Table I are
compared:
Conventional composite (Estilux, Kulzer):
A silanised lithium-aluminum glass of an average grain size
of approximately 4 ~m serves as a filler. The filler content
is approximately 75% (m/m).
Hybrid composite (Degufill H, Degussa):
Silanised barium-aluminum-silicate glass with an average
grain size of approximately 2 ~m but which is up to 100%
finer than 5 ~m serves as a filler as does as a silanised
highly dispersed SiO2. The degree of filler in the glass
amounts to approximately 70% (m/m) and that of the highly
dispersed sio2 is approximately 11% (m/m). This results in a
total content of inorganic fillers of approximat~ly 8% (mjm).
; Microfiller composite (Durafill, Kulzer & Co. GmbH):
~ . .
A silanised highly dispersed SiO2 with a mean grain size
between 0.01 and 0.04 ~m serves as a filler. The degree of
filling amounts to approximately 50% (m/m).
- 27 -
, . . . :
, ' : - ':
-
,, :- , . ~ ' - ' '~
- ~ ~ . ' '
20~5081
All of these substances were hardened with a translux lamp
(Kulzer) with a radiation time of 40 seconds.
Thermo-hardened laboratory test product = VP (data in parts
by weight):
VP1:17 Bis-GMA
7.7 TEDMA
Barium-aluminum-silicate glass, silanised
(average grain size approximately 4
mlcro-
metres)
0.3 Dibenzoylperoxide
VP2:35 Bis-GMA
14.7 TEDMA
highly dispersed sio2 silanized (average
grain size 0.1 - 0.04 ~m)
0.3 Dibenzoylperoxide
These pastes were hardened as were the heat hardened
substances according to the present invention.
- 28 -
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