Note: Descriptions are shown in the official language in which they were submitted.
S~
This invention relates to dental compositions.
It is well known that dental compositions which
contain polymerizable monomers which are to be used ~or the
~illing o~ teeth ~nd for dentures can be hardened by a polymeri-
zation reaction induced by radicals~ Esters of acrylic acid
and methacrylic acid are monomers which are suitable for these
purposes. If bifunctional acrylic acid esters are employed
in such polymerization reactions, three-dimensional, cross-
linked thermosetting masses of great hardness and abrasion
resistance are obtained. U.S. Patent 3,066,112 describes the
use of one dimethacrylic acid ester, derived from bisphenol A
and obtainable by its reaction with glycidylmethacrylate, to
be used specifically for the preparation of tooth fillings~
Similar products, which however are free of any hydroxyl groups,
are described by British Patent 1,267~564 and U.S. Patent
3,~23,740 which are identical with German Patent 1,921,~69.
The polymers obtained by means of these substances have the
advantage that they will remain dimensionally stable even in
the presence of wàter due to the absence of the hydroxyl groups
which is in contrast to the masses described by U.S. Patent
3,066~112 which, being produced by the addition of the bisphenol
A to the epoxy group of the glycidylmethacrylate, contain two
hydroxyl ~roups per molecule of the dimethacrylic acid compound.
These known bifunctional methacrylic acid esters are
utilized in combination with radical-forming polymerization
catalysts or initiators, especially in dentistry as masses
or compositions for the filling of teeth and represent a
definite improvement when compared with the previously used
Bi
. . - . - . . . . . 1
:, ' ' . ,. ~ ,1, . ,
. . .
5~7
methylmethacrylates. They will polymerize quickly and thoroughly
without any residual monomers and have a lesser con~raction at
polymerization which is a main advantage. The hardened materlal
possesses a high compressive strength as reported in the papers
writ~en by Henry L. Lee et al in J. Dent. Res. 48, pages 526
to 535 (1969) and by H. Durner in "Zahnaerztliche Welt/Reform",
81, page 764 ~1972).
However, these masses obtained by the use of known
bifunctional methacrylic esters, in spite of the relatively
great strength of the fillings and dentures, still do not meet
all dental re~uirements. Tooth fillings a~d dentures are
5ubjected in the course of their use to an enormous chewing
pressure and to wear by abrasion. It is for this reason that
many dentists, in spite of the availability of these prepara-
tions, are still using amalgam for the filling of teeth although
this latter material is deficient in esthetic respect and there
are some objections to its use in view of its mercury content.
Attempts have been made by the admixture of fillers~ especially
powdered silica or fine amorphous silicic acid, to improve
still further the strength and abrasion characteristics of the
polymerized masses. Such attempts, also including the use of
tri- and tetra-functional methacrylic acid esters, were proposed
by the published German application~ 24 05 578, 24 32 013 and
24 38 411. However, the resulting products were not satisfactory.
~ he compressive strength values attained at the present
time are in the general range of 2,200 to 2,~0 kg/cm~O Such
products are acceptable in many instances but there is still a
- 3 -
desire for tooth fillings and dentures of even greater strength
and resistance to abrasion which are based on easily obtainable
raw materials which can then be rapidly polymerized by the use
of standard polymerization catalysts and initiators and which
will fully harden within a short period of time, even without
any increase in temperature.
In one embodiment, the present invention provides a
dental composition, especially for tooth fillings and dentures,
including at least two components, one component comprising a
polymerizable diacrylic acid ester selected from the group
consisting of the diacrylic acid or dimethacrylic acid ester
of bishydroxymethyltricyclo [5.2.1. o2 ~6] -decane and mixtures
thereof, the other component comprising a radical-forming sub-
stance. The term "radical-forming substance" will be under-
stood to include a compound which will form radicals under
irradiation by light.
In another embodiment, the present invention provides
a method for forming dental fillings and prosthetic dental appli-
ances in which a polymerizable diacrylic or di~ethacrylic acid
ester is polymerized to form a hardened product, the improvement
~herein at least 20 percent by weight of said polymerizable
ester is the ester of bishydroxymethyltricyclo [5.2.1. o2 ~ 6]_
decane.
In still another embodiment, the present invention
provides an improved dental composition having shortened harden-
ing time and after hardening, increased compressive stren~th and
abrasion resistance comprising a polymerizable acrylic or metha-
crylic acid ester or diester and a radical-forming compound, at
least 20 percent of the polymerizable ester being the diacrylic
acid or dimethacrylic acid ester of bishydroxymethyltricyclo
[5,2.1.02'6]-decane.
_ 4 _
-
It has been found unexpectedly and surprisingly that
diacrylic or dimethacrylic acid esters of blshydroxymethyl-
tricyclo [5.2.1.O2'6]-decane are particularly suitable poly-
merizable components for dental materials and will lead t~
dimensionally stable and hard polymerization products. The
diacrylic or dimethacrylic acid ester compounds can be produc-
ed easily by esterifying dihydroxymethyltricyclodecane with
aerylic or methaerylic acid or a derivative thereof by means
of standard processes.
Dihydroxymethyltricyclo [5.2.1.02'6]-decane is com-
mercially available and can be expressed by the following
structural formula
: I~ ~f H20H
H~H2 - ~ 4 (I)
As a result o~ the standard processes used for the
preparation of this tricyclodecane derivative, the hydroxy-
methyl radicals can be in the 3- and 4-position as well as in
the 9- and 8-position of the tricyclodecane molecule. The
commercially available product, described for example in the
published German patent application 1 618 384, normally will
contain these isomeric compounds. The published German applica-
tion 1 694 868 describes the use of such compound for the manu-
~aeturing of polyadducts based in triglycidylisocyanurate.
B~ - 5 -
.
The bifunc~ional bisacrylic acid esters or bismeth-
acrylic acid esters of the dihydroxymethyltricyclodecane are
compounds expressed by the general formula
(2)
~2~ ~ / \ / (2) (II)
H H2
where R represents the methylene acrylate radical of the
formula
-CH -OC0-C - CH (III)
and where R' can be either H or CH30
In the general formula (II), the symbol CH~2~ is
meant to indicate that two H~atoms are present at this C-atom
of the isomeric compound if the radical R is not present there.
These esters can be easily prepared in accordance
with conventional methods by esterifying the dihydroxymethyl-
tricyclodecane with the free acrylic acids in the presence of
suitable catalysts, or by trans-esterification and the use of
acrylic acid esters of lower alcohols, for example methacrylic
aeid methylester. By the admixture of polymerization inhibitors,
such as p-methoxyphenol, during esterification or trans-ester_
ification, undesirable polymerization at higher temp~ratures
ean thus be preven-ted in known manner.
,.,
The bifunctional ac~ylic esters of formula (II) are
colorless, very fluid oils which due to their viscosity (which
is relatively light in comparison with the bifunctional
methacrylic acid esters used heretofore in dentistry), can
be processed very readily. The compositions prepar~d in
accordance with the present invention can contain known radical-
pxoducing substances used for such polymerization purposes
and in the same amounts as generally used for such purposes.
Suitable polymerization catalysts are, among other substances,
peroxide ox azo-compounds, especially lauroyl peroxide,
chlorobenzoyl peroxide and the like. For ields of application
requiring rapid polymerization at room temperature, especially
in the case of materials used for the ~illing of teeth, the
known oxidation-reduction systems are preferably used, which
systems usually consist of one peroxide and one reducing
agent. The reducing agent can be, for example, amines,
sulphinic acids, substituted sulphones, so-called CH-active
compounds such as barbituric acids or ~-diketones. Non~dis-
coloring redox systems are preferably used. I~ amine-containing
xedox-systems are employed, amines should be selected which
are relatively stable with respec~ to discoloring, especially
N,N-bishydroxyalkyl-3,5-xylidines or N,N-bis-hydroxyalkyl-3,5-
di~t-butylanilines.
If compounds are present which will initiate polymeri-
zation when subjected to visible or ultra~violet light, it
becomes possible to attain a rapid polymexization by irradiation,
a particularly advantageous feature for many purposes.
7 --
Compositions containing suitable W initiators
are very stahle in the dark and the substances proposed by
the invention will therefore permit the manufacture of single-
unit preparations which are ready for use. For this purpose,
a conventional initiator for ultra-violet polymerization, for
example, benzoin, benzoin ether, ~-substituted benzoins or
benzoin ethers~ benzil, benzilketals, halogeneous aromatic
compounds such as halogen-methylated benzophenones and the like
is dissolved in the bifunctional esters. The admixture of
small quantities of organic phosphites will lead to an even
gxeater acceleration of rapidly progressing polymerization by
ultra-violet light.
Single-unit preparations containing polymerization
initiators which react to visible light can be hardened with
particular ease. Initiators of this type are, for example,
combinations of quinones and aliphatic amines, or combination
of benzilketals, benzophenones or quinones with amines.
Preparations containing such initiator systems are suficiently
stable in the dark and allow sufficient time for processing
under daylight or other light of usual intensity. ~Iowever,
polymerization will be rapid if the substance is subjected
to an intensive visible irradiation furnished by a special
light source.
~ he bifunctional esters of the present invention
are designed for materials to be used in the dental field
which includes tooth fillers as well as preparations for
building up portions of a tooth, coating and sea1ing masses,
.
: . :
priming materials for cavities, materials for jackets, bridges
and facings, masses for the manu~acture of artificial teeth,
materials for prosthetic devices as well as orthodontic devices.
In practice, these materials can be utilized in all cases
where synthetic or polymerizable materials are normally used
in the dental field.
The substances can be used either as two-component
systems, for example, as preparations consisting of one unit
containing the monomer and one filling-material unit which
contains the polymerization catalyst, or in the form of two
liquid components or two paste components, with the two
components o redox-systems distributed among the two units.
It is also possible to prepare the substances proposed by the
invention in a pre-apportioned form, that is, in plastic
containers where the components are originally kept separately
and where a mechanical mixing process will occur when the two
components are combined with each other. Another advantageous
use is possible in the polymerization of tooth-filling and
sealing masses initiated by ultra-violet or visible light,
where the masses are furnished, preferably in the form of
single units ready for use.
The bifunctional methacrylic acid esters which are
used in accordance with the present invention result in an
increase in the strength of the materials in comparison with
materials used heretofore. It is possible, for example, to
raise the compressive strength of tooth fillings, accomplished
with standard paste-paste preparations, from approxima~ely
2,500 kg/cm2 to approximately 4,000 l~g/cm2 simply by replacing
the known bifunctional methacrylic esters with the esters
proposed by the present invention. Furthermore, the hardening
will then also be greatly accelerated. If standard redox-
systems are being used, the time elapsing from the start of
the gelling up to the final hardening will be reduced to one-
half or even one-fourth of the conventional time without any
change in the processing time (that is, the time up to the
start of the polymerization). This feature is particularly
important in case of preparations which are applied inside the
mouth, especially when tooth fillings are being inserted.
The bifunctional esters used in accordance with the
present invention can be mixed with conventional monofunctional
acrylic esters and methacrylic esters. They can also be util-
ized in conjunction with known bifunctional methacrylic esters.
For example, an admixture of bifunctional esters disclosed by
British Patent 1,267,564, U. S. Patent 3,923,740 or German
Patent 1,921,869, which are free of hydroxyl groups, can be
used to define a specific refractive index, or the co-use oE
esters which were disclosed by U. S~ Patent 3,066,122 and
- which do contain hydroxyl groups, can serve to define a low
but specifica]ly desired water absorption by the polymeriza-
tion products which in many cases is expedient in order to
avoid marginal leaking of tooth fillings. The combinations
of the substances proposed by the invention with these known
monomeric d:iacrylates or alkanedioldiacrylates result sur
prisingly in polymerization products possessing a strength
which is only slightly lower and in some instances even greater
~3 - 10 -
.
j . , . , . , . ,, . . , . ,, ,, . ~ . . . ...
5~
than the strength of the substances of the invention employed
without any admixture. Such mixtures should contain at least
20 percent of the particular tricyclodecane monomers proposed
by the invention, based on the total polymerizable monomeric
content of the composition. I~nown bifunctional monomers which
are particularly suitable for this novel combination with the
monomeric compounds of the invention are the diacrylate or di-
methacrylate of hexanediol, 2,2-bis-[p-(~-hydroYyethoxy)-
phenyl]-propane or of 2,2-bis-[p-(~-hydroxypropoxy)-phenyl]-
10 propane. On the basis of such combinations, it becomes possibleto create particularly high-grade dental preparations, especial-
ly compositions for the filling and sealing of teeth, either on
a paste/paste basis or in the form of single-unit systems. In
the case of the first-mentioned method, one paste can contain a
tricyclodecane monomer substance proposed by the invention,
and the other a known monomeric substance, if the redox catalyst
system is used, one paste will contain the peroxide and the
other paste the activator. The single-unit systems comprise
mixtures of the diacrylates proposed by the invention and known
monomers such as hexanedioldimethacrylate. After the mixture of
o~ the two pastes tor after irradiation of the compositions
which contain polymerization activators responsive to light),
hardening will occur, resulting in polymerization products
with superior strength characteristics.
The use of conventional fillers is possible and
eff~ctive. Especially suitable are quartz and quartz glass, as
well as other glasses, for example, glasses having alumino-
silicate bases, and glasses which will provide the dental mat-
erials with some opacity to X-rays, such as barium and lanthanum
glasses. These inorganic fillers are silanized in a ~nown manner.
The same applies to fibers, for example, quartz or glass fibers,
which can be admixed to improve the mechanical c~aracteristics
B
$~7
of the materials. Insoluble inorganic salts or minerals, for
example, calcium fluoride, can also be used as fillers. The
exclusive or additional use of micro-fine fillers, especially
amorphous SiO2 or A1203, with particle sizes ranging from 10
to 10 6 mm, can also lead to advantageous results, especially
for the stabilization of viscosity.
The admixture of organic polymers generally used for
dental medicine and technology, especially in connection with
the manufacture of dentures, is also feasible. Particularly
applicable are the polymethacrylic esters, usually available in
pearl-form and tinted to match the color of the teeth. Obvious-
ly, conventional pigments, soluble dyes and so-called brighten-
ers, used to produce a white fluorescence, etc. can also be
admi~ed with the materials proposed by the in~ention.
In order to prevent premature polymerlzation, it will
be expedient to admix antioxidants, especially of the phenolic
type, for example, p-methoxyphenol, hydroquinone or 2,6-di-t-
butyl-p-cresol, into the composition of the present invention.
The compositions can also contain UB-absorbing s~abilizers to
prevent discoloration caused by light, for example, derivatives
of benzotriazoles, benzophenones or benzoic acid phenyl esters.
The latt~r admixtures are especially useful for preparations
which are not polymerized by ultra-violet light.
The various additional ingredients such as W-initia-
tors, fillers, pigments, antioxidants and the like described a
above are utilized in the composition of the present invention
in amounts corresponding to those generally utilized for such
materials in compositions according to the present state of -the
art.
- 12 -
~ .
; . . - . I
Th~ invention is additionally illustrated in connec-
tion with the following Examples which are to be considered as
illustrative of the present invention. It should be understood,
however, that the invention is not limited to the specific
details of the Examples. In these Examples, ~he bis-hydroxy-
methyltricyclo-[5.2.1.02'6]-decane is referred to as T-diol, and
its diacrylic acid and dimethacrylic acid esters as T-diacrylate
or T-dimethacrylate, respectively.
E_AMPLE 1
~Preparation of the bifunctional methacrylester of the T-diol)
98 grams of T-diol, 129 grams of methacrylic acid
and 200 ml of cyclo~exane are heated in the presence of 7
grams of p-toluenesulphonic acid and 0.3 grams of picric acid
for 24 hours while the water is distilled off. The reaction
product is then rinsed repeatedly with a 2N-caustic soda
solution and water and decolorized by treating it with A12O3.
10 mgrams of p-methoxyphenol are admixed as a stabilizer to
prevent premature polymerization, and the cyclohexane, used
as solvent, is removed by evacuation.
The reaction yields 124 grams of dimethacrylate
ester in the form of an almost colorless, very fluid oil
having the following properties:
Viscosity at 25~C 1.~ P
1.~008
Double bond equivalent 170; 169
.
~ ~$~
EXAMPLE 2
(Prepara~ion of the bifunctional acr~vlic ester of the T-diol)
196 grams of T-diol, 216 grams of acrylic acid and
400 ml of hexane are heated in the presence of 14 grams of
p-toluenesulphonic acid and 0.7 gram of picric acid for six
hours while t}le water is distilled off. After processing as
described in Example 1, there is obtained 171 grams of a
colorless oil with the following properties:
Viscosity at 25C 1.2 P
nD0 1.5040
Double bond equivalent 155; 158
EXAMPLE_3
(Preparation of an acrylic-methacrylic mixed ester of
the T-diol)
59 grams of T-diol, 22 grams of acryllc acid, 52
grams of methacrylic acid, 100 ml of cyclohexane, 4 grams of
p-toluenesulphonic acid and 0.16 grams of picric acid are
together heated and the reaction mixture is processed as
described in Example 1. There is obtained 71 grams o~ a
colorless oil with the following properties:
Viscosity at 25C 1.2 P
nDO 1.5020
Double bond equivalent 168, 172
Approximately 40% of the ester groups of the resulting product
are acrylic acid radicals.
~B 1~
5~
EXAMPLE 4
(Comparative Test, polymerization by heat)
For this comparative test, the known product used is
a dimethacrylate derived from bisphenol-A, produced in accordance
with the example 10 of German Patent 1,921,869.
In order to determine the compressive stren~th of the
ultimate polymerization products, the known dimethacrylate as
well as the T-dimethacrylate of the invention (formed in a
manner as in Example 1) are each mixed with 0.6% of lauroyl
peroxide, the two solutions are filled into ten cylindrical
forms, each form possessing a diameter of 4 mm and a height
of 8 mm, and heated, at a temperature of 130C for 30 minutes.
The following average values for compressive strength
are found when the test specimens are measured:
Product according to the
present invention1 720 kg/cm2
Product according to example 2
10 of German Patent 1,921,869 1 150 kg/cm
EXAMPLE 5
(Comparative Test, oxidation-reduction polymerization)
Two solutions are prepared containing the same
amount of T-dimethacrylate. Dissolved in one solution is
0.8% of N,N-bis-hydroxyethyl-3,5-di t-butylaniline and dissolved
in the other solution is 1.0% of p-chlorobenzoyl peroxide~
After mixing of equal parts of the resulting solutions, forms
are filled in the same manner as described in Example 4. ~
hard, transparent polymerization product is obtained after a
few minutes.
- ~5 -
In the same manner, there are prepared similar solu-
tions from the dimethacrylate of 2,2-bis-[p-(~-hydroxypropoxy)-
phenyl]-propane, the synthesis o~ which is described in German
Patent 1,921,869. These solutions are processed to form speci-
men or like dimensions.
The specimens are stored for 24 hours at 36C.The following data are then found for the average compressive
strength:
Product acco.rding to the 2
present invention 1 640 kg/cm
Product of the present 2
state of the art 1 160 kg/cm
EXAMPLE 6
(Paste/paste preparation for tooth fillings)
Two pastes(denominated "A" and "B") are prepared by
kneading together the following: .
Paste A) 2.4 grams of N,N-bishydroxyethyl-3~5-di-t-
butylaniline, dissolved in 300 grams of T-
methacrylate
1.8 grams of amorphous, silanized SiO2 with
an average primary particle size of 12 nm and
990 grams of silanized quartz powder ( ~60~um)
tinted to match the tooth color
Paste B~ 300 grams of T-dimethacrylate
1.8 grams of the SiO2 as used in Paste A
990 grams of silanized quartz powder (C 60/um
tinted to match the tooth color and containing
6.0 grams of p-chlorobenzoyl peroxide.
B - 16
..~ 7
~ hen equal parts of the two pastes A and B are mixed
together, a relatively smooth, easily applied mass is obtained
which can be inserted in the usual manner into pre-finished
cavities and which will harden there within approximately
three minutes. The filling can then be finished and polished.
EXAMPLE 7
(Comparative Test)
The process described in E~ample 6 is repeated and
~ive cylindrical forms are prepared for each paste with the
dimensions as listed in Example 4.
For comparison purposes, two pastes are prepared
with the same composition as in Example 6 except that the di-
methacrylate disclosed in German Patent 1,921,869 and listed
in Exampl~ 5 above, is substituted for the T-dimethacrylate.
Cylindrical forms are prepared in the identical-manner for each
c~omposition. After 24-hour storage at 36C, the following
average values for compressive strength are found:
Pastes based on T-dimethacrylate 4,050 kg/cm2
Pastes according to the present 2
state of the art 2,630 kg/cm
EXAMPLE 8
(Paste/paste preparation for tooth fillings)
Two pastes (denominated "A" and "B`' are prepared by
kneading together the following:
- 17 -
......
- ~ :
- Paste A) 1.8 grams of ~ bis-hydroxyethyl-3,5-di-t-
butylaniline, dissolved in 300 grams of T-
diacrylate
1.8 grams of amorphous, silanized SiO2
at an average primary particle size of 12 nm
and
990 grams of silanized quartz powder (<60 ~lm~,
tinted to match the tooth color, and
Paste B) 300 grams of T-diacrylate
1.8 grams of SiO2 as used in Paste A
990 grams of silanized quartz powder (~O~um),
tinted to match the tooth color and containing
6.0 grams of p-chlorobenzoyl peroxide.
When equal parts of the two pastes are mixed together,
the processing span (counting from the beginning of the inter-
mixing) is approximately 1 minute and 50 seconds at 24~C. The
hardening process is then checked by means of a rheometer and
it is thus determined that the mass has substantially solidi-
fied and hardened after an additional 25 seconds~
The comparative paste/paste mixtu.re prepared in
Example 7 in accordance with the present state of art requires,
at the identical processi~g span and temperature, approximately
90 seconds for the subsequent hardening which shows that the
compositions prepared in accordance with the present invention
harden more rapidly, allowing an earlier finishing operation,
thus advantageously reducin~ the waiting time for the dentlst
and patient for the completion of a filling.
E~ 18 -
.
EXAMPLE 9
(Combination of T-diacrylate of the present invention
~ith a dimethacrylate prepared in accordance with the
present state of the art)
Two pastes (denominated "A" and "B") are prepared~
Paste A corresponds to Paste ~ of Example 8. Paste B (the
peroxide-containing paste) corresponds to Paste B of Example 8
except that the dimethacrylate of 2,2-bis-[p-(~-hydro~ypropoxy-)
phenyl]-propane disclosed ~y German Patent 1,921,S69 is utilized
in place of the T-diacrylate.
The pastes are mixed in a ratio (by weight) of 1 : 1
and the compressive strength is determined by means of test
specimen as described in Example 4. The average value so
measured is 3,640 kg/cm2 which is definitely higher than for
standard preparations for the filling of teeth even though
only one of the components was prepared on the basis of a
substance proposed by the present invention.
EXAMPLE 10
~Preparation for tooth fillings in a pre-apportioned form)
Mixing containers àS proposed by the published
German application 23 24 296 are used. 96 mgrams of T-
diacrylate, containing 0.3~ of N,N-bis-hydroxyethyl-3,5-di-t-
butylaniline are fused as individual units into foil cushions
which consist of aluminum lined wi'h polypropylene. The
cushions are fastened under a clasp which embraces the main
pocket. The main pocket is filled in each case with 330 mgrams
of silanized quartz powder (~60 ~m), tinted to match the tooth
color and containing 0.2% of p-chlorobenzoyl peroxide.
19
: . ' ' ; .: '' . ,
Pressure is then exerted upon the clasp by a suitable
device, causing the foil cushion to burst and its contents
to enter the main pocket. The container is then placed into
a mechanical shaker, mixed and the resulting mi~ture is inserted
directly into a properly prepared tooth cavity. The processing
span is approximately 2 minutes at 23C, and the hardening ls
substantially completed after another 1 minute.
EXAMPLE 11
(Comparative abrasion tests)
Paste/paste preparations based on T-dimethacrylate
as defined in Example ~ and based on the diester disclosed by
German Patent 1,921,869 as defined in Example 7, in each case
mixed in a 1 : 1 ratio, are prepared.
In order to test the abradability of these compositions,
round test specimen of 20 mm diameter and 1.5 mm thickness are
produced in properly formed metallic molds. Their weight is
then determined. The specimen are then contacted for 24 hours
by a suspension of calcium carbonate in water (weight ratio
of 1 : 1.5) and by motor-driven standardi~ed circular brushes
of 10 mm diameter rotating at 60 rpm. The bearing weight of
the brushes is 500 grams. After drying, the loss of weight
of the specimen is determined with the following results:
Abrasion Loss
Preparation based on T-dimethacrylate 0.3 mgram
Preparation according to the state 2O7 mgram
of the art
-- ~0 --
~ ~r~5~7
~ he already low abrasion of the preparation according
to the state of art is reduced still further by use of a sub-
stance propos~d by the invention, approximately by a power of
ten, thus again proving the superiority of the novel preparation
of the present invention for the filling of teeth.
EXAMPLE 12
. . .
(Tooth-filling material which is polymerizable by ultra-violet light)
A composition for tooth filling which can be hardened
by ultra-violet light and which is ready for use is prepared
by first mixing 100 grams of T-dimethacrylate with 0.5 gram
of ~-(2-cyanethyl)-benzoinmethylether and kneading the resulting
mixture with 5 grams of the SiO2 powder defined in Example 8
and 345 grams of silanized quartz powder (particle size ~!60 ~n),
tinted to match the color of the tooth.
When irradiated by a commercially available UV
polymerization unit with a 70 mW output, a mass with a thickness
of 2 mm hardens after six seconds.
EXAMPLE 13
. .
(Tooth-filling material which is polymerizable by visible light)
By kneading together of 20 grams of T-acrylate, 88
grams of silanized quartz powder (~60 ~ ), tinted to match the
tooth colox, 1 gram of SiO2 as defined in Example 8, 0.8 gram
of methacrylic acid-(N,N-dimethylamino)-ethylester and 4 mgrams
of phenanthrenequinone, there is obtained a preparat~on for the
filling of teeth which is ready for use an~ which will remain in
~.
- 21
_. :
5~ ~
easily workable condition in diffused daylight or under a
standard 65-watt bulb for more than five minutes. Hardening
is accomplished by irradia~ion with a halogen-projector lamp
(12 V, 75 watt) and cold-light mirror. Light with wavelengths
~400 nm is screened off by a filter. After an irradiation time
of 20 seconds, the mass with a thickness of 2.5 mm is hardened.
EXAMPLE 14
(Sealing composition for dental-enamel fissures)
Two solutions are prepared based on T-dimethacrylate,
with one solution containing 0.45% of N,N-bishydroxyethyl-p-
toluidine and the other 0.4~ of chlorobenzoyl peroxide. Equal
portions of these solutions are then mixed together.
The sealing composition so produced is applied to
the enamel of the tooth after it has been slightly etched in
the usual manner with a 30~ solution of phosphoric acid.
Hardening begins after approximately one minute and is substan-
tially complete after approximately two minutes, resulting in
a seal that is smooth and resistant to abrasion.
EXAMPLE 15
(Coating preparations for too h fillings which can be hardened
by ultra-violet light including the combination of known diacrylates
with substances proposed by the invention)
The various diacrylates listed in the Table below
are admixed in the parts by weight indicated therein. 0.3%
hy wei~ht of benzildimethylketal and 0.5% by weight of didecyl-
phenylphosphite are dissolved in each mixture and 35~ by weight
o~ silanized, pyro-SiO2 is added and uniformly distributed.
The coating compositions so obtained can be spread easily.
The compressive strength of coatings based on these
compositions is measured by the use of specimen having the di-
mentions 2 x 2 x 4 mm. Hardening is accomplished by irradia-
tion with a commercially available W-polymerization unit with
an output of 70 mW. The values obtained are shown in the
Table below.
Compressive
10 Composition strength2
(in parts by weight) (kg/cm )
. . . ~
T-diacrylate T-dimeth- hexane- hexane-
acrylate diol- diol-
dimeth- diacrylate
acrylate _ _ __
100 o o o 3,940
0 100 0 0 3,900
-0 50 0 5,750
0 50 50 0 6,030
o 66.7 33.3 o 5,300
0 0 50 5,~00
_ ._ _ . _ . . .
Surprisingly, combinations of the diester compounds
proposed by the present invention with the hexanedioldi(meth)-
acrylate in weight ratios ranging from 1 : 1 to 2 1 show
substantially greater compressive strength values than when
-only the substances proposed -by the invention are used. The
use of a coating composition based on the pure hexanedioldi-
(meth)acrylate wlthout the admixture of T-diacrylate and/or
- 23 ~
- .
~$~
T-dimethacrylate is not Ieasible in practice due to the enor-
mous brittleness of the hardened mass~ The combination with the
the T-diester compound in the manner proposed by the present
invention reduces this brittleness and, at the same time, im-
proves the compressive strength of the hardened composition.
EXAMPLE 16
(Manufacture of a jacket crown)
A paste is made of T-acrylate-methacrylate (mixed
esters prepared in accordance with Example 3) and solid poly-
methylmethacrylate in pearl form, commercially available invarious tooth color schemes in a ratio of 2 : 3. The several
color shades o~ the pearl polymerization product were previous-
ly mixed in each case with 0.4% of lauroyl peroxide.
Onto an isolated tooth base, serving as a model/
there are deposited layers of the necessary color shades to
match the color of the natural teeth. Each layer is briefly
heated to approximately 140C by a flow of hot air. After the
completion of the crown, polymerization is carried out for 10
minutes at 150aC. The crown so obtained is very highly resis-
tant to abrasion and appears very close to the natural teeth.
EX~MPLE-17
(~acing of a bridge consisting of noble metals)
T-methacrylate and polymethylmethacrylate-pearl poly-
merization product, tinted to match the color of the teeth and
previously impregnated with 0.4% of lauroyl peroxide are used.
- 24 -
as in Example 16, by making the two components into a paste,
at a ratio of 2 : 3.
Onto the frame of the bridge (which is provided in
the usual manner with retaining means) the individual color
shades are applied in layers at the front side, with each layer
hardened as described in Example 16.
The facings are distinguished by their excellent
stability and especially by a high resistance to abrasion
throughout their use inside the mouth. In addition, their
appearance is faultless.
The principles, preferred embodiments and modes of
operation of the present invention have been described in the
foregoing specification. The invention which is intended to
be protected herein, however, is not to be construed as limited
to the particular forms disclosed, since these are to be regarded
as illustrative rather than restrictive. Variations and changes
may be made by those skilled in the art without departing from
the spirit of the invention.
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. . .
