Liquid crystalline (meth)acrylate compounds, composition and method

A liquid crystalline compound, a polymeric product formed by polymerization of the liquid crystalline compound, a dental composition including the liquid crystalline compound and method of using the dental composition. Polymerization of the liquid crystalline compound results in an low volume percent shrinkage and a high conversion to polymer. The composition of the invention is useful for dental adhesive, primer, cement, pit and fissure sealant and restorative.

The invention relates to liquid crystalline (meth)acrylates suitable for 
dental and medical applications, as well as for optical, electrooptical 
application such as in liquid-crystal displays. The invention provides 
(meth)acrylate compounds which are liquid below 50.degree. C., and are 
useful in compositions for treating natural teeth, such as dental 
restorative, cement, adhesive, primer, sealant and root canal filling 
compositions. The invention provides dental cement compositions and 
methods of using them for binding hard tooth material, metal and ceramic. 
The cement compositions include polymerizable ethylenically unsaturated 
monomers. The cements have superior adhesion to tooth without separately 
acid etching dentin or enamel. Compositions of the invention are useful as 
dental cements, liners, bases and restoratives. Compositions of the 
invention include less reactive diluent than prior art compositions. 
Compositions of the invention polymerize to form polymeric material having 
low or no residual monomer, preferably less than 1 percent residual 
monomer. 
A series of acrylate, methacrylate or vinyl terminated compounds comprising 
a mesogenic or rigid rod-like moiety including (meth) acrylate terminated 
oligomers I and II with a mesogenic terephthaloyl ester moiety are 
disclosed by G. G. Barclay, C. K. Ober, Prog. Polym. Sci. 18 (1993) 899; 
D. J. Broer, G. N. Mol, Polym. Engng. Sci. 31 (1991) 625; R. A. M. Hikmet, 
J. Lub, J. A. Higgins, Polymer 34 (1993) 1736. 
##STR1## 
p-Hydroxy benzoic ester moieties incorporated into vinyl terminated 
compounds III are disclosed by D. J. Broer, J. Lub, G. N. Mol, Macromol. 
26 (1993)1244. 
##STR2## 
A diacrylate (wherein R is H) and a dimethacrylate (wherein R is CH.sub.3) 
having the formula IV which comprises a biphenylhydroxy moiety is 
disclosed by H. Litt Morton, Wha-Tzong Whang, Kung-Ti Yen, Xue-Jun Qian, 
in J. Polym. Sci., Part A,: Polym. Chem. 31 (1993) 183, Morton H. Lift US 
89-369205. 
##STR3## 
Acetylene terminated aromatic ester having the formula V are described by 
E. P. Douglas, Polymer Prep. 34 (1993) 702. 
##STR4## 
Methacrylates having the formula VI with a ridged rod-like moiety are 
disclosed in T. Shindo, T. Uryu, Liquid Crystals 15 (1993) 239). 
##STR5## 
A vinyl terminated bishydroxybenzoate having formula VII which comprises 
spacers and exhibits relatively low phase transition temperatures only on 
cooling (n=11: i65n62s.sub.A 47s.sub.B 31k) and relatively narrow liquid 
crystalline phases, are disclosed by H. Anderson, F. Sahlen, and U. W. 
Gedde, A. Hult, in Macromol. Symp. (1994) 339. 
Mixtures of (meth)acrylates comprising liquid crystalline monomers, 
dimethacrylates 
(2,2-Bis-[p-(2-hydroxy-3-methacryloyloxypropoxy)-phenyl]propane) and 
di(meth) acrylates comprising liquid crystalline monomers are described in 
EP 0379058. 
However, the known liquid crystalline mono- or difunctional molecules have 
melting temperatures and liquid crystalline behavior at temperatures above 
50.degree. C. (Table 1 below, page 28). An application of these molecules 
in the liquid crystalline phase require temperatures over their melting 
temperature (50 to 170.degree. C.). An application at room temperature is 
only possible in the solid state or in solution (25-30 volume % solvent). 
In accordance with the invention monomers are provided which are liquid at 
room temperature and which show liquid crystalline behavior at least 
between 20 and 40.degree. C. These liquid crystalline monomers are useful 
in dentistry, medicine, microelectronics and optoelectronics. 
It is an object of the invention to provide a polymerizable compound within 
the scope of the general formula: 
##STR6## 
wherein R.sub.1 is a group of the general formula 
EQU -A-, -A-Y.sub.1 -B-, -A-Y.sub.1 -B-Y.sub.2 -C 
or a steroidal moiety, preferably selected of the group of cholesteryl 
compounds, wherein 
each A, B and C independently is a substituted or unsubstituted aromatic 
moiety having 6 to 24 carbon atoms, a substituted or unsubstituted 
heteroaromatic moiety having 2 to 24 carbon atoms or a substituted or 
unsubstituted cycloalkylene moiety having 5 to 30 carbon atoms, a 
substituted or unsubstituted alkylene moiety having 2 to 20 carbon atoms 
each Y.sub.1 and Y.sub.2 independently is a covalent bond, OCO, N.dbd.N, 
CH.dbd.N, C.dbd.C, CO, O(CO)O, O, S, SO.sub.2, OCS, CH.sub.2 --O, CH.sub.2 
--S, 
##STR7## 
each L.sub.1 and L.sub.2 independently is a hydrogen, a alkylene having 1 
to 20 carbon atoms or CN 
R.sub.3 is a covalent bond or a substituted or unsubstituted alkylene 
having 1 to 20 carbon atoms, oxyalkylene having 1 to 20 carbon atoms, 
thioalkylene having 1 to 20 carbon atoms or a carboxyalkylene having 1 to 
20 carbon atoms 
R.sub.4 is hydrogen, a substituted or an unsubstituted alkyl having 1 to 20 
carbon atoms, cycloalkyl having 5 to 12 carbon atoms, or aryl rest having 
6 to 20 carbon atoms, 
M is a mesogenic group of the general formula 
EQU -A-Z, -A-Y.sub.1 -B-Z, -A-Y.sub.1 -B-Y.sub.2 -C-Z 
or a steroidal moiety, preferably selected of the group of cholesteryl 
compounds, wherein 
each A, B and C independently is a substituted or unsubstituted aromatic 
moiety having 6 to 24 carbon atoms, a substituted or unsubstituted 
heteroaromatic moiety having 2 to 24 carbon atoms or a substituted or 
unsubstituted cycloalkylene moiety having 5 to 30 carbon atoms 
each Y.sub.1 and Y.sub.2 independently is a covalent bond, OCO, N.dbd.N, 
CH.dbd.N, C.dbd.C, CO, O(CO)O, O, S, SO.sub.2, OCS, CH.sub.2 --O, CH.sub.2 
--S, 
##STR8## 
each L.sub.1 and L.sub.2 independently is a hydrogen, a alkylene having 1 
to 20 carbon atoms or CN 
Z is a hydrogen, halogen, CN, --OR, COOR, NO.sub.2, a halogen substituted 
or unsubstituted alkylene or alkenyl having 1 to 20 carbon atoms, a 
halogen substituted or unsubstituted oxyalkylene or oxyalkenyl having 1 to 
20 carbon atoms, a halogen substituted or unsubstituted thioalkylene or 
thioalkenyl having 1 to 20 carbon atoms, a halogen substituted or 
unsubstituted carboxyalkylene or alkanoylenoxy having 1 to 20 carbon 
atoms, 
X is a covalent bond, CO, NHCO, OCO 
n is an integer from 1 to 10.

BRIEF DESCRIPTION OF THE INVENTION 
The invention provides a polymerizable compound within the scope of the 
general formula: 
##STR9## 
wherein R.sub.1 is a group of the general formula -A-, -A-Y.sub.1 -B-, 
-A-Y.sub.1 -B-Y.sub.2 -C-, or a steroidal moiety, preferably selected of 
the group of cholesteryl compounds, wherein each A, B and C independently 
is a substituted or unsubstituted aromatic moiety having 6 to 24 carbon 
atoms, a substituted or unsubstituted heteroaromatic moiety having 2 to 24 
carbon atoms or a substituted or unsubstituted cycloalkylene moiety having 
5 to 30 carbon atoms, a substituted or unsubstituted alkylene moiety 
having 2 to 20 carbon atoms, each Y.sub.1 and Y.sub.2 independently is a 
covalent bond, OCO, N.dbd.N, CH.dbd.N, C.dbd.C, CO, O, S, SO.sub.2, 
O(CO)O, OCS, CH.sub.2 --O, CH.sub.2 --S, 
##STR10## 
each L.sub.1 and L.sub.2 independently is a hydrogen, an alkyl having 1 to 
20 carbon atoms, an alkylene having from 2 to 20 carbon atoms or CN, 
Alternatively, R.sub.1 is expressed as a group of the general formula 
-R.sub.10 -, -R.sub.10 -Z.sub.1 -R.sub.11 -, -R.sub.10 -Z.sub.1 -R.sub.11 
-Z.sub.2 -R.sub.12 -, or a steroidal moiety, preferably selected from the 
group of cholesteryl compounds, wherein each R.sub.10, R.sub.11, and 
R.sub.12 independently is a substituted or unsubstituted aromatic moiety 
having 6 to 24 carbon atoms, a substituted or unsubstituted heteroaromatic 
moiety having 2 to 24 carbon atoms or a substituted or unsubstituted 
cycloalkylene moiety having 5 to 30 carbon atoms, a substituted or 
unsubstituted alkylene moiety having 2 to 20 carbon atoms, each Y.sub.1 
and Y.sub.2 independently is a covalent bond, OCO, N.dbd.N, CH.dbd.N, 
C.dbd.C, CO, O, S, SO.sub.2, O(CO)O, OCS, CH.sub.2 --O, CH.sub.2 --S, 
##STR11## 
each L.sub.1 and L.sub.2 independently is a hydrogen, an alkyl having 1 to 
20 carbon atoms, an alkylene having from 2 to 20 carbon atoms or CN, 
R.sub.3 is a covalent bond or a substituted or unsubstituted alkylene 
having 1 to 20 carbon atoms, oxyalkylene having 1 to 20 carbon atoms, 
thioalkylene having 1 to 20 carbon atoms or a carboxyalkylene having 1 to 
20 carbon atoms, 
R.sub.4 is hydrogen, a substituted or an unsubstituted alkyl having 1 to 20 
carbon atoms, cycloalkyl having 5 to 12 carbon atoms, or aryl rest having 
6 to 20 carbon atoms, 
M is a mesogenic group of the general formula -A-Z, -A-Y.sub.1 -B-Z, 
-A-Y.sub.1 -B-Y.sub.2 -C-Z, or a steroidal moiety, preferably selected of 
the group of cholesteryl compounds, wherein each A, B and C independently 
is a substituted or unsubstituted aromatic moiety having 6 to 24 carbon 
atoms, a substituted or unsubstituted heteroaromatic moiety having 2 to 24 
carbon atoms or a substituted or unsubstituted cycloalkylene moiety having 
5 to 30 carbon atoms, each Y.sub.1 and Y.sub.2 independently is a covalent 
bond, OCO, N.dbd.N, CH.dbd.N, C.dbd.C, CO, O, S, SO.sub.2, O(CO)O, OCS, 
CH.sub.2 --O, CH.sub.2 --S, 
##STR12## 
Alternatively, M is expressed as a mesogenic group of the general formula 
-R.sub.10 -Z, -R.sub.10 -Z.sub.1 -R.sub.11 -Z, -R.sub.10 -Y.sub.1 
-R.sub.11 -Z.sub.2 -R.sub.13 -, or a steroidal moiety, preferably selected 
of the group of cholesteryl compounds, wherein each R.sub.10, R.sub.11 and 
R.sub.12 independently is a substituted or unsubstituted aromatic moiety 
having 6 to 24 carbon atoms, a substituted or unsubstituted heteroaromatic 
moiety having 2 to 24 carbon atoms or a substituted or unsubstituted 
cycloalkylene moiety having 5 to 30 carbon atoms, each Z.sub.1 and Z.sub.2 
independently is a covalent bond, OCO, N.dbd.N, CH.dbd.N, C.dbd.C, CO, O, 
S, SO.sub.2, O(CO)O, OCS, CH.sub.2 --O, CH.sub.2 --S, 
##STR13## 
each L.sub.1 and L.sub.2 independently is a hydrogen, an alkyl having 1 to 
20 carbon atoms, an alkylene having from 2 to 20 carbon atoms or CN, 
Z is a hydrogen, halogen, CN, --OR, COOR, NO.sub.2, a halogen substituted 
or unsubstituted alkylene or alkylidene having 1 to 20 carbon atoms, a 
halogen substituted or unsubstituted oxyalkylene or oxyalkylidene having 1 
to 20 carbon atoms, a halogen substituted or unsubstituted thioalkylene or 
thioalkylidene having 1 to 20 carbon atoms, a halogen substituted or 
unsubstituted carboxyalkylene or alkanoylenoxy having 1 to 20 carbon 
atoms, 
X is a covalent bond, CO, NHCO, OCO and n is an integer from 1 to 10. 
DESCRIPTION OF THE INVENTION 
Preparation of liquid crystalline (meth)acrylates 
In accordance with the invention are prepared liquid crystalline 
(meth)acrylates within the scope of general formula 1 which have at least 
two polymerizable double bonds and at least two rigid rod-like moieties 
R.sub.1 and M 
##STR14## 
General formula 1 is alternatively written as general formula 1A as 
follows: 
##STR15## 
In formula 1 and 1A R.sub.1 is a group of the general formula 
EQU -A-, -A-Y.sub.1 -B-, -A-Y.sub.1 -B-Y.sub.2 -C- 
or a steroidal moiety, preferably selected of the group of cholesteryl 
compounds, wherein 
each A, B and C independently is a substituted or unsubstituted aromatic 
moiety having 6 to 24 carbon atoms, a substituted or unsubstituted 
heteroaromatic moiety having 2 to 24 carbon atoms or a substituted or 
unsubstituted cycloalkylene moiety having 5 to 30 carbon atoms, a 
substituted or unsubstituted alkylene moiety having 2 to 20 carbon atoms 
each Y.sub.1 and Y.sub.2 independently is a covalent bond, OCO, N.dbd.N, 
CH.dbd.N, C.dbd.C, CO, O(CO)O, O, S, SO.sub.2, OCS, CH.sub.2 --O, CH.sub.2 
--S, 
##STR16## 
each L.sub.1 and L.sub.2 independently is a hydrogen, an alkyl having 1 to 
20 carbon atoms, an alkylene having from 2 to 20 carbon atoms or CN 
R.sub.3 is a covalent bond or a substituted or unsubstituted alkylene 
having 1 to 20 carbon atoms, oxyalkylene having 1 to 20 carbon atoms, 
thioalkylene having 1 to 20 carbon atoms or a carboxyalkylene having 1 to 
20 carbon atoms 
R.sub.4 is hydrogen, a substituted or an unsubstituted alkyl having 1 to 20 
carbon atoms, cycloalkyl having 5 to 12 carbon atoms, or aryl rest having 
6 to 20 carbon atoms, 
M is a mesogenic group of the general formula 
EQU -A-Z, -A-Y.sub.1 -B-Z, -A-Y.sub.1 -B-Y.sub.2 -C-Z 
or a steroidal moiety, preferably selected of the group of cholesteryl 
compounds, wherein 
each A, B and C independently is a substituted or unsubstituted aromatic 
moiety having 6 to 24 carbon atoms, a substituted or unsubstituted 
heteroaromatic moiety having 2 to 24 carbon atoms or a substituted or 
unsubstituted cycloalkylene moiety having 5 to 30 carbon atoms 
each Y.sub.1 and Y.sub.2 independently is a covalent bond, OCO, N.dbd.N, 
CH.dbd.N, C.dbd.C, CO, O(CO)O, O, S, SO.sub.2, OCS, CH.sub.2 --O, CH.sub.2 
--S, 
##STR17## 
each L.sub.1 and L.sub.2 independently is a hydrogen, an alkyl having 1 to 
20 carbon atoms, an alkylene having from 2 to 20 carbon atoms or CN 
Z is a hydrogen, halogen, CN, --OR, COOR, NO.sub.2, a halogen substituted 
or unsubstituted alkylene or alkenyl having 1 to 20 carbon atoms, a 
halogen substituted or unsubstituted oxyalkylene or oxyalkenyl having 1 to 
20 carbon atoms, a halogen substituted or unsubstituted thioalkylene or 
thioalkenyl having 1 to 20 carbon atoms, a halogen substituted or 
unsubstituted carboxyalkylene or alkanoylenoxy having 1 to 20 carbon 
atoms, 
X is a covalent bond, CO, NHCO, OCO 
n is an integer from 1 to 10. 
Compounds with the scope of general formulas A and B are within the scope 
of general formula 1 and 1A. 
Preferably liquid crystalline (meth)acrylates have structures A and B. 
##STR18## 
A macromonomer within the scope of general formula 5 is formed by reaction 
of a 2,3-epoxypropyl (meth)acrylate compound within the scope of general 
formula 4, a diphenol compound within the scope of general formula 3 and a 
diepoxide compound within the scope of general formula 2 as follows. 
##STR19## 
In general formulas 2 through 5 R.sub.2 is a group of the general formula 
EQU -A-, -A-Y.sub.1 -B-, -A-Y.sub.1 -B-Y.sub.2 -C- 
or a steroidal moiety, preferably selected of the group of cholesteryl 
compounds, wherein 
each A, B and C independently is a substituted or unsubstituted aromatic 
moiety having 6 to 24 carbon atoms, a substituted or unsubstituted 
heteroaromatic moiety having 2 to 24 carbon atoms or a substituted or 
unsubstituted cycloalkylene moiety having 5 to 30 carbon atoms, a 
substituted or unsubstituted alkylene moiety having 2 to 20 carbon atoms 
each Y.sub.1 and Y.sub.2 independently is a covalent bond, OCO, N.dbd.N, 
CH.dbd.N, C.dbd.C, CO, O(CO)O, O, S, SO.sub.2, OCS, CH.sub.2 --O, CH.sub.2 
--S, 
##STR20## 
each L.sub.1 and L.sub.2 independently is a hydrogen, an alkyl having 1 to 
20 carbon atoms, an alkylene having from 2 to 20 carbon atoms or CN 
R.sub.4 is hydrogen, a substituted or an unsubstituted alkyl having 1 to 20 
carbon atoms, cycloalkyl having 5 to 12 carbon atoms, or aryl rest having 
6 to 20 carbon atoms, 
R.sub.1 is a substituted or unsubstituted aryl having from 6 to 24 carbon 
atoms and/or a substituted or unsubstituted cycloalkyl having from 5 to 12 
carbon atoms. Preferably R.sub.1 is 
##STR21## 
wherein R.sub.5 is hydrogen, alkyl having from 1 to 12 carbon atoms, 
cycloalkyl having from 5 to 12 carbon atoms, aryl having from 6 to 18 
carbon atoms and 
Y is substituted or unsubstituted alkylene having from 1 to 5 carbon atoms, 
0, CO, OCO, S, SO.sub.2 and, 
n is an integer from 1 to 10. Preferably n is 1, 2, or 3. 
The reaction of epoxide di(meth)acrylates compounds within the scope of 
general formula 5 with organic acids within the scope of general formula 6 
or derivatives thereof, with isocyanates within the scope of general 
formula 7 or alcohols 8 within the scope of general formula leads to 
modified di(meth)acrylates having ester moieties, urethane linkages or 
ether moieties 1 and 1A within the scope of general formula. 
##STR22## 
In the general formulas 6, 7 and 8 are R.sub.3 is a covalent bond or a 
substituted or unsubstituted alkylene having 1 to 20 carbon atoms, 
oxyalkylene having 1 to 20 carbon atoms, thioalkylene having 1 to 20 
carbon atoms or a carboxyalkylene having 1 to 20 carbon atoms 
M is a mesogenic group of the general formula 
EQU -A-Z, -A-Y.sub.1 -B-Z, -A-Y.sub.1 -B-Y.sub.2 -C-Z 
or a steroidal moiety, preferably selected of the group of cholesteryl 
compounds, wherein 
each A, B and C independently is a substituted or unsubstituted aromatic 
moiety having 6 to 24 carbon atoms, a substituted or unsubstituted 
heteroaromatic moiety having 2 to 24 carbon atoms or a substituted or 
unsubstituted cycloalkylene moiety having 5 to 30 carbon atoms 
each Y.sub.1 and Y.sub.2 independently is a covalent bond, OCO, N.dbd.N, 
CH.dbd.N, C.dbd.C, CO, O(CO)O, O, S, SO.sub.2, OCS, CH.sub.2 --O, CH.sub.2 
--S, 
##STR23## 
each L.sub.1 and L.sub.2 independently is a hydrogen, an alkyl having 1 to 
20 carbon atoms, an alkylene having from 2 to 20 carbon atoms or CN 
Z is a hydrogen, halogen, CN, --OR, COOR, NO.sub.2, a halogen substituted 
or unsubstituted alkylene or alkenyl having 1 to 20 carbon atoms, a 
halogen substituted or unsubstituted oxyalkylene or oxyalkenyl having 1 to 
20 carbon atoms, a halogen substituted or unsubstituted thioalkylene or 
thioalkenyl having 1 to 20 carbon atoms, a halogen substituted or 
unsubstituted carboxyalkylene or alkanoylenoxy having 1 to 20 carbon 
atoms, 
The esterification, etherification and urethane formation of the 
di(meth)acrylate hydroxyl groups is carried out in solutions. As solvents 
for the esterification were used tetrahydrofurane, dioxane, CH.sub.2 
Cl.sub.2, DMF or others, or polymerizable monomers such as 
triethyleneglycol bismethacrylate, diethyleneglycol bismethacrylate, 
dioxolan bismethacrylate, vinyl-, vinylene- or vinylidene-, acrylate- or 
methacrylate substituted spiroorthoesters and 
2,2-bis[p-(acryloxyethoxy)phenyl] propane. 
For example a liquid crystalline di(meth)acrylate within the scope of 
structural formula 9 is synthesized in the following manner: 2,3-epoxy 
propoxy methacrylate and 4,4'-dihydroxy biphenyl are mixed and reacted for 
15 hours at 115.degree. C. to form a methacrylate terminated macromonomer 
having hydroxyl groups. The macromonomer hydroxyl groups are then 
esterified by mixing at 23.degree. C. with 4'-cyano-biphenyl 4-oxy-valeric 
carboxylic acid and dicyclohexylcarbodiimid and than for further 24 hours 
at 23.degree. C. to form a compound of the structural formula: 
##STR24## 
The compositions of the invention are formulated as one, two or more 
components, UV curable, visible light curable, self cure, and/or dual cure 
product or combinations of these. The composition of a preferred 
embodiment of the invention includes polymerizable carboxylic acid 
monomer, an optional filler and/or diluent, a cationic elutable glass or 
other source of polyvalent cations, and a polymerization catalyst system. 
Fillers which are suited for use in compositions of the invention are 
organic and/or inorganic particles, for example inorganic glasses such as 
are used in glass ionomer cements. Exemplary of such fillers are those of 
U.S. Pat. No. 4,814,362 which is incorporated herein by reference in its 
entirety. Preferred fillers are glasses formed from or including, barium, 
calcium, strontium, lanthanum, tantalum, and/or tungsten silicates and 
aluminates and/or aluminosilicates, silica, including submicron silica, 
quartz, and/or ceramics for example, calcium hydroxy apatite. In a 
preferred embodiment of the invention reactive cations, especially those 
of calcium, strontium and aluminium, and anions especially fluoride ions; 
are eluted from the fillers. The fillers used in the invention preferably 
are reduced in particle size and are preferably silanated before they are 
incorporated into such compositions. Preferred levels of filler are from 
about 20% to about 85% based on the total weight of the composition, with 
from about 40% to about 85% being more preferable and about 50-80% being 
most preferred. If a more finely particulated filler is used, amounts of 
filler may be decreased due to the relative increase in surface area which 
attends the smaller sizes of particles. Preferred particle size 
distributions are from 0.02 to 50 microns, more preferably 0.1 to 10 
microns, and most preferably 1 to 6 microns. 
Mixing the compositions of the present invention may be achieved using 
standard compounding techniques. For example, liquids, photoinitiator(s), 
and accelerator(s) are blended first, and fillers are added incrementally 
thereafter. When blending light sensitive compositions, however, a 
photosafe room illumination, i.e., one that does not contain substantial 
amounts of wavelengths of electromagnetic radiation that would activate 
the photoinitiating system is used to avoid initiating polymerization of 
the composition prematurely. 
The compounds of the present invention also have medical applications such 
as in self adhesive bone cements. However, they are most preferred to use 
in dental treatment by application to a tooth or a number of teeth in 
vivo, in the mouth of a live patient by a dentist or dental practitioner. 
The application of the compositions of the invention is preferably as a 
polymerizable dental composition applied to tooth. In a preferred 
embodiment of the invention a dental cement composition includes a 
compound within the scope of general formula 1, and other ingredients, 
such as curing catalysts, initiators, accelerators, diluents and/or 
adjuvants. The composition is applied as a cement using conventional 
techniques and preferably cured with application of visible light in a 
conventional manner. Cements in accordance with the invention are self 
adhesive to dentin and enamel. These cements are used in bonding denin to 
structures, for example, to bond a ceramic inlay to a prepared cavity of a 
tooth. Inlays preferably are polymers, or ceramics which are cast or 
built-up from porcelain frits and fired. Alternatively, inlays are 
machined from metal such as titanium or gold or performed polymeric 
composite or homogeneous monolithic polymer compositions, for example by 
CAD-CAM procedures. In accordance with a preferred embodiment of the 
invention metal or ceramic superstructures for crowns, and bridges and/or 
orthodontic appliances are bonded to teeth using cement compositions of 
the invention. Such cement compositions join metal or ceramic to tooth by 
application of the cement composition by bringing them into contact until 
the cement hardens. 
A preferred composition of the invention includes a two-part system. One 
part includes an initiator. The second part comprises filled and the 
co-initiator. The two parts are spatuled to form a cement prior to 
placement on tooth. The placement is by standard technique(s). Preferably 
the cement includes a visible light and/or a self-curing redox 
polymerization initiator system. In a preferred embodiment of the 
invention luting cement compositions have low viscosity and film 
thicknesses less than about 25 .mu.m to bond close fitting appliances to 
prepared teeth. In one embodiment luting cement compositions of the 
present invention may be prepared of such high viscosity and consistency 
that they form adhesive "glue" lines of thicknesses up to several hundred 
microns to lute less close fitting restorations, for example inlays 
prepared using present state-of-the-art CAD-CAM devices. Compositions of 
the invention are mechanically strong, abrasion resistant, and are 
esthetically suitable and serve as the sole structural element to retain 
inlay, crowns and bridges or other appliances to tooth structure. 
A preferred dental treatment in accordance with the invention is the 
application of dental filling compositions which include an initiator and 
at least one compound within the scope of general formula 1. Preferably 
the dental filling composition includes finely divided filler. Preferably 
the composition is applied to a tooth as a filling material using 
conventional techniques as a one-component material and is cured with 
application of visible light in conventional manner. 
In a preferred embodiment of the invention a one or two component pit and 
fissure sealant which includes at least one compound within the scope of 
general formula 1 is applied to anatomic defects and/or the exterior of 
teeth. The sealant limits the ability of caries-forming bacteria to 
colonize the pits, fissures and other surfaces of the teeth. Pit and 
fissure sealant compositions in accordance with the invention are an 
especially valuable means of reducing caries by filling and eliminating 
enamel defects. The pit and fissure sealants of the invention are 
preferably applied with or without prior acid etching or the use of rubber 
dam to teeth. In one embodiment fluoride eluting compounds and glasses are 
preferably included in compositions of the invention. Fluoride is eluted 
to reduce the incidence of caries in tooth substance adjacent the 
compositions of the invention. 
Preferred compositions of the invention include two or more ethylenically 
unsaturated materials are included in compositions of the invention. The 
polymerizable monomer is preferably liquid at 23.degree. C., and comprises 
from about 0.5 to about 99.998% by weight of the composition, with amounts 
ranging from about 1 to about 99.98% being preferred, and amounts ranging 
from about 1.5 to about 99.8% being more preferred. 
Preferred compositions of the invention include an adhesion promoter for 
example a phosphorus-containing adhesion promoter which is free from any 
halogen atoms covalently or otherwise bonded directly to a phosphorus 
atom. The phosphorus derivative may be polymerizable or non-polymerizable, 
however the preferred phosphorus-containing adhesion promoters comprise 
polymerizable phosphorus materials having ethylenic unsaturation and 
include, among others, organic esters of one or more acids of phosphorus 
(hereinafter referred to as phosphorus acid esters), wherein the organic 
portion of the ester contains at least one polymerizable ethylenically 
unsaturated group. The organic portion of the ester may be alkenyl, 
alkenoxy, cycloalkenyl, aralkenyl, or alkenaryl, and preferably may have 
from 2 to 40 carbon atoms. The organic portion may be straight chain, 
branched, or cyclic, can contain skeletal hetero atoms, i.e., atoms other 
than carbon, and can be unsubstituted or substituted with moieties which 
do not interfere with the free radical polymerization of the phosphorus 
acid esters. 
Examples of saturated and unsaturated phosphorus acid esters which may be 
used include, but are not limited to, monomers containing phosphoric acid 
groups such as hydroxyethyl methacrylate monophosphate, 2,2,'-bis(alpha 
-methacryloxy- beta -hydroxypropoxyphenyl) propane diphosphonate (BIS-GMA 
diphosphonate), BIS-GMA diphosphate, dibutyl phosphite, di-2-ethylhexyl 
phosphite, di-2-ethylhexyl phosphate, glyceryl-2-phosphate, 
glycerylphosphoric acid, methacryloxyethyl phosphate, and glyceryl 
dimethacrylate phosphate. Other suitable polymerizable phosphorus acid 
esters are disclosed, for example, in U.S. Pat. No. 4,499,251 to Omura et 
al, U.S. Pat. No. 4,222,780 to Shibantani et al, U.S. Pat. No. 4,235,633 
to Tomioka, U.S. Pat. No. 4,259,117 to Yamauchi et al, U.S. Pat. No. 
4,368,043 to Yamauchi et al. Of the polymerizable phosphorus acid 
compounds disclosed in the above patents and application, each of which is 
incorporated herein by reference, the preferred compounds are those 
polyethylenically unsaturated monophosphates of the formula: 
##STR25## 
and salts thereof, in which R is an organic radical having a valency of 
n+1; and R may be interrupted by one or more oxygen atoms and may be 
substituted or unsubstituted, and may comprise an aliphatic radical, or a 
cycloaliphatic radical, or an aryl radical; 
R.sup.1 is a hydrogen atom, alkyl having from 1 to 3 carbon atoms, halogen 
or --C.dbd.N, and 
n is an integer of at least 1. Preferably n is an integer of 2 or more, and 
more preferably from 3 to 6. Examples of the preferred compounds include 
pentaerythritol triacrylate monophosphate, pentaerythritol trimethacrylate 
monophosphate, dipentaerythritol pentaacrylate monophosphate, and 
dipentaerythritol pentamethacrylate monophosphate. When included the 
phosphorus acid compound may comprise from about 0.25 to about 99.998% by 
weight of the adhesive composition, with amounts ranging from about 1 to 
about 50% being preferred. In a more preferred embodiment the phosphorus 
acid compound would comprise from about 2 to about 29.8% by weight of the 
composition. 
Preferred compositions of the invention include a catalyst component which 
may comprise any free radical initiators normally used in conjunction with 
polymerizable ethylenically unsaturated materials, although those which 
will initiate polymerization at room temperature are more preferred. Thus, 
the catalyst may comprise, for example, an organic peroxide type initiator 
such as dibenzoyl peroxide, dilauroyl peroxide, acetyl peroxide, t-butyl 
peroxybenzoate, cumene hydroperoxide and the like. In a preferred aspect, 
the catalyst comprises an actinic light sensitive initiator, such as 
ultraviolet light-sensitive initiators or visible light sensitive 
initiators. As examples of suitable ultraviolet light-sensitive initiators 
there may be mentioned the monoketals of an aromatic 1,2-diketone, 
benzophenones, substituted benzophenones, benzoin methyl ether, 
isopropoxybenzoin, benzoin phenyl ether or benzoin isobutyl ether. Among 
the suitable visible light sensitive initiators, alpha-diketones, such as 
camphoroquinone, are particularly preferred. The preferred initiators are 
the visible light sensitive initiators. The catalyst generally is employed 
in the range of from about 0.001 to about 10% of the composition. In a 
preferred embodiment the catalyst is used within the range of from 0.01 to 
about 5%. In a still further preferred embodiment, from about 0.1 to about 
2% by weight of catalyst is employed. 
In a preferred embodiment of the invention, polymerizable compositions are 
provided which include an accelerator system comprising (1) an amine or 
amine salt and/or (2) a sulfinic acid or salt thereof and/or (3) a metal 
salt or organo metal compound. In a preferred embodiment both the amine or 
amine salt and the sulfinic acid or salt thereof are present. The amine or 
amine salt may be present in an amount from 0 to about 20% by weight of 
the composition, whereas the sulfinic acid or salt thereof is present in 
an amount of from about 0 to about 10%, the combined amount being from 
about 0.001 to about 20 percent. In a preferred embodiment, the amine or 
amine salt is in the range of 0.001 to about 10% by weight of the 
polymerizable composition, and the sulfinic acid or a sulfinic acid salt 
is in the range from about 0.01 to about 5 percent by weight of the 
polymerizable composition, the combined weight being in the range from 
about 0.01-15% by weight. In a still more preferred embodiment, the amine 
or amine salt is in an amount from about 0.1-8 percent by weight of the 
polymerizable composition and the sulfinic acid or salt thereof is in an 
amount from 0.1-2 percent by weight of the polymerizable composition, the 
combined amount ranging from about 0.2 to 10 percent by weight of the 
polymerizable composition. 
The amine or amine salt employed in a preferred embodiment of this 
invention desirably is a secondary or tertiary amine rather than a primary 
amine, since the use of a secondary or tertiary amine leads to 
significantly accelerated curing. Examples of suitable amines include 
N,N-dimethylaniline, N,N-dimethyl-p-toluidine, 
N-methyl-N-beta-hydroxyethylaniline. 
Primers and adhesives of the invention may be filled to such an extent that 
they would serve not only as primers and adhesives, but also as pit and 
fissure sealants and dental filling composites. A primer, composition of 
the invention comprises by weight about 5-20% PENTA, 0-61% hydroxyethyl 
methacrylate, 0.1% butylated hydroxytoluene. 
All of the percentages recited herein are by weight based on the weight of 
the entire composition unless otherwise stated. 
EXAMPLE 1 
Synthesis of 4.4'-Bis-(2-hydroxy-3-methacryloylpropoxy)-biphenyl 
60.00 g (0.422 mol) 2,3-Epoxypropoxy methacrylate, 0.40 g 
2,6-Di-tert.-butyl-cresol, 39.3 g (0.211 mol) 4,4'-Dihydroxybiphenyl and 
250 ml 1-Methoxy-2-propanol are heated until a homogeneous clear liquid is 
formed. After adding 0.30 g 1,8-Diaza-bicyclo-[5.4.0]-undec-7-ene the 
mixture were kept for 15 hours at 115.degree. C. Then the mixture is 
concentrated and dropped into petrolether and cooled onto 0.degree. C. The 
separated solid is filtered and washed with petrolether and dried. The 
crude product is recrystallized from 200 ml ethanol dissolved in a small 
amount DMSO and filtered over Al.sub.2 O.sub.3 (act. II/III, app. 500 g) 
using acidic ethyl ester/petrol ether. After removing the solvents 14 g of 
pure 4,4'-Bis-(2-hydroxy-3-methacryloylpropoxy)-biphenyl is obtained. 
.sup.1 H NMR: 7.6/7.05 (Ar), 6.1/5.7 (CH.sub.2 .dbd.C--), 5.45 (OH), 4.3, 
4.1 (CH, CH.sub.2 OCO), 4.0 (CH.sub.2 OAr), 1.9 (CH.sub.3). 
.sup.13 C NMR: 166.3 (CO), 157.4/132.3/127.1/114.7 (Ar), 135.6 (C.dbd.), 
125.8 (CH.sub.2 .dbd.), 69.0 (CH.sub.2 O), 66.6 (CH), 65.5 (CH.sub.2 OCO), 
17.8 (CH.sub.3). 
Esterification of 4.4'-bis-(2-hydroxy-3-methacryloylpropoxy)-biphenyl with 
4'-Cyano-biphenyl-4-oxyvaleric carboxylic acid 
6,50 g (22 mmol) 4'-Cyano-biphenyl-4-oxyvalerian carboxylic acid, 4,71 g 
(10 mmol) 4,4'-bis-(2-hydroxy-3-methacryloylpropoxy)-biphenyl and 0,25 g 
dimethylamino pyridine were dissolved in 85 ml CH.sub.2 Cl.sub.2 /DMF 
(vol.-ratio 9:8). To the mixture were added 5,00 g (24,2 mmol) 
dicyclohexyl carbodiimid. Then the mixture were stirred for 24 hours at 
room temperature. After this time the precipitated solid was filtered off. 
To the filtrate were added 0,1 g BHT and the solvent was removed by vacuum 
distillation. The viscose residue was dissolved in 100 ml CH.sub.2 
Cl.sub.2 and cooled to 0.degree. C. The precipitating solid was removed 
and the filtrate was washed twice with 50 ml 1 n HCl, 50 ml 1 n 
NaHCO.sub.3 solution and with 150 ml water and filtered over silica. 
Furthermore, the solution was dried over NaSO.sub.4 and the solvent was 
removed to obtain 5.5 g of 
4,4'-bis-(2-hydroxy-3-methacryloylpropoxy)-biphenyl esterified with 
4'-Cyano-biphenyl-4-oxyvaleric carboxylic acid. 
APPLICATION EXAMPLE 1 
To 5.00 g liquid crystalline di(meth)acrylate of Example 1 are added and 
0,05 g JRAGCURE 651 (Ciba--Geigy). Using a curing unit (Dentsply De Trey) 
the mixture is polymerized by irradiation with visible light during 40 
seconds. The degree of polymerization is about 85%. The obtained material 
shows a volume shrinkage of 2.4 percent. The thermo-mechanical properties 
are shown in FIG. 1 wherein E' (storage modulus) is 2.8.multidot.10.sup.9 
Ps (25.degree. C.), E" (loss modulus) is 2.9.multidot.10.sup.8 Pa 
(25.degree. C.) and tan .delta. (E"/E') is 0.22. 
COMATIVE EXAMPLE 1 
To 7.000 g of 
(2,2-Bis-[p-(2-hydroxy-3-methacryloyloxypropoxy)-phenyl]propane) and 3.000 
g of triethyleneglycol dimethacrylate were added 0,050 g 
N,N-di-(.beta.-hydroxyethyl)-p-toluidine and 0.050 g champhorquinone. 
Using a curing unit (Dentsply De Trey) the mixture was polymerized by 
irradiation with visible light during 40 seconds. The degree of 
polymerization is about 65%. The obtained material shows a volume 
shrinkage of 6.5 percent. 
Synthesis of 4,4'-bis-(2-hydroxy-3-methacryloylpropoxy)-biphenyl as 
described in example 1 
Esterification of 4,4'-bis-(2-hydroxy-3-methacryloylpropoxy)-biphenyl with 
4'-Cyano- biphenyl-4-oxyundecane carboxylic acid 
11.39 g (30 mmol) 4'-Cyano-biphenyl-4-oxyundecane carboxylic acid, 6.59 g 
(14 mmol) 4,4'-bis-(2-hydroxy-3-methacryloylpropoxy)-biphenyl and 0.32 g 
(2,6 mol) dimethylamino pyridine were dissolved in 160 ml CH.sub.2 
Cl.sub.2 /DMF (having a volume ratio 5:3). To the mixture were added 6,60 
g (32 mmol) dicyclohexyl carbodiimid. Then the mixture were stirred for 27 
hours at room temperature. After this time the precipitated solid was 
filtered off. To the filtrate were added 0.15 g BHT and the solvent was 
removed by vacuum distillation. The viscose residue was dissolved in 250 
ml CH.sub.2 Cl.sub.2 and cooled to 0.degree. C. The precipitating solid 
was removed and the filtrate was washed twice with 150 ml with 1 n HCl, 
150 ml 1 n NaHCO.sub.3 solution and with 75 ml water and filtered over 
silica. Furthermore, the solution is dried over NaSO.sub.4 and the solvent 
is removed. 
Yield: 6.9 g 
Table 1 shows the Melting Points (.degree. C.) of LC-Monomers II-VI and the 
glass transition temperatures of Examples 1 and 2. 
______________________________________ 
LC-Monomer R/X Melting point (.degree. C.) 
______________________________________ 
II H 108 
II CH.sub.3 86 
III -- 52 
IV 84 
V Cl 157 
V OCH.sub.3 154 
V CH.sub.3 169 
VI H 87-89 
VI CH.sub.3 98-99 
Example 1 18* 
Example 2 6** 
______________________________________ 
*At 18.degree. C. the glassy product of Example 1 becomes a liquid and 
from 18 to 67.5.degree. C. remains in the nematic phase. 
**At 6.degree. C. the glassy product of Example 2 becomes a liquid and 
from 6 to 59.5.degree. C. remains in the nematic phase. 
EXAMPLE 3 
Self-Curing, Two Component, Powder and Liquid Cement 
0.92 grams of the dried product prepared as described in Example 2 and 0.08 
grams of triethyleneglycol dimethacrylate are dissolved in one another to 
form a liquid. 1.0 grams of this liquid is added to 2.0 grams of the 
strontium aluminofluorosilicate containing powder. The consistency of the 
mixture is suitable for use as a luting or crown and bridge or orthodontic 
cement or as a filling material. Polymerization is induced by the redox 
polymerization system of benzoyl peroxide, ascorbyl palmitate and copper 
acetyl acetonate. The powder and liquid compositions are as follows: 
______________________________________ 
PERCENT 
BY 
WEIGHT 
______________________________________ 
POWDER 
Strontium fluoroaluminosilicate cement 98.83 
(Glass) 
Benzoyl peroxide 1.00 
ascorbyl palmitate 0.15 
copper acetyl acetonate 0.02 
LIQUID 
Product of example 2 92.00 
Triethylene glycol dimethacrylate 8.00 
______________________________________ 
The powder and liquid are mixed in a 1:1 ratio by volume to form a cement. 
This cement is adhesive to dentin and enamel without further treatment 
except cleansing with pumice. 
EXAMPLE 4 
Esterification of 
(2,2-Bis-[p-(2-hydroxy-3-methacryloyloxypropoxy)-phenyl]propane) with 
11-[4'(trans-4-propyl-cyclohexyl)-phenoxy]-undecane carboxylic acid 
1.50 g (3.73 mmol) 11-[4'(trans-4-propyl-cyclohexyl)-phenoxy]-undecane 
carboxylic acid. 0.87 g (1.69 mmol) 
(2.2-Bis-[p-(2-hydroxy-3-methacryloyloxypropoxy)-phenyl]-propane) and 0.05 
g dimethylamino pyridine were dissolved in 20 ml CH.sub.2 Cl.sub.2. To the 
mixture were added 0.85 g (4.10 mmol) dicyclohexyl carbodiimid at 
0.degree. C. Then the mixture stirred for 24 hours at room temperature. 
After this time the precipitated solid was filtered off. To the filtrate 
were added 0.05 g BHT and the solvent was removed by vacuum distillation. 
The viscose residue was washed with pentane and filtered over aluminum 
oxide. The separation of the disubstituted product from mono-substituted 
impurities occurs by column chromatography(silica, CHCl.sub.3). After 
evaporation of the solvent was obtained a highly viscous, slightly yellow 
liquid crystalline substance. The liquid crystalline dimethacrylate 
exhibits a glass transition temperature of T.sub.g -10.degree. C. It shows 
a liquid crystalline behavior between -10 and 19.degree. C. (smectic 
phase). The yield is 0.77 g. 
.sup.13 C-NMR: 14.4 (CH.sub.2 --CH.sub.3). 18.3 (C.dbd.C--CH.sub.3). 20.1 
(CH.sub.2 --CH.sub.3). 24.9-37.0 (aliphatic CH.sub.2 and cyclohexyl). 29.5 
(C--CH.sub.3). 39.8 (CH.sub.2 -cyclohexyl). 43.7 (C--CH.sub.3). 62.9 
(COO--CH.sub.2). 66.3 (Ph--OCH.sub.2). 69.4 (CH--O). 114.2-135.8 (aromatic 
carbons). 126.2 (.dbd.CH.sub.2). 135.8 (.dbd.C). 157.2-157.5 (aromatic 
carbons). 166.9 (.dbd.C(CO.sub.2)--). 173.1 ((CH.sub.2).sub.4 --CO.sub.2 
--). 
##STR26## 
It should be understood that while the present invention has been described 
in considerable detail with respect to certain specific embodiments 
thereof, it should not be considered limited to such embodiments but may 
be used in other ways without departure from the spirit of the invention 
and the scope of the appended claims.