FI58065B - TANDFYLLNINGSMATERIAL INNEHAOLLANDE EN BLANDNING AV ETT BINDEMEDEL OCH ETT FYLLMEDEL - Google Patents

Description

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Patent · och registrentyrelten 'AraMon uttagd och utUkriftun publicund 29.08.80 (32) (33) (31) Pyydetty atuolkw · -Bn ** prtorltut 2U. OU. 73 2U.0U.73 Engianti-England (GB) 19277/73 19270/73 (71) Imperial Chemical Industries Limited, Imperial Chemical House, Millbank,

London S.W.l, England-England (GB) (72) John Burnett Cantwell, Runcorn, Cheshire, Michael Edward Benet Jones,

Runcorn, Cheshire, Leuan Thomas, Runcorn, Cheshire, James Rodney Traynor, Runcorn, Cheshire, Edward Charles Dart, Runcorn, Cheshire,

Joseph Franciszek Jaworzyn, Runcorn, Cheshire, Jozef Nemcek, Runcorn, Cheshire, England-England (GB) (7U) Oy Kolster Ab (5U) Dental filler containing a mixture of binder and filler -Tandfyllningsmaterial innehällande en blandning av ett bindemedel och ett fme Ilme del

The invention relates to a dental filler comprising a mixture of a binder and a filler.

The invention is characterized in that the binder is a polymerizable material comprising a) a polymerizable prepolymer containing at least two ethylenically unsaturated groups and which is the reaction product of a urethane prepolymer and an acrylate ester having the formula

Bo B ^ R_

, 3, 6, T

CH 2 = C-C0-0-CH-CH-0H

wherein R 1 is hydrogen or methyl and R 8 and R 2 represent hydrogen or one of them is hydrogen and 8. the other methyl, wherein the urethane prepolymer is a reaction product of a diisocyanate of the formula OCH-R 2 iCO and a diol of the formula HO-R 8 -OH, in which R1 is a cycloaliphatic, aromatic or aliphatic group and Rg is a residue of a condensate between an alkylene oxide and a compound containing phenol groups, and 2,58065 h) up to 100% by weight of vinyl monomer, based on the amount of polymerizable prepolymer, and that the filler is present 90% by weight of the dental filler and that it is an inert, inorganic, finely divided filler, of which at least $ 50 of the particles have a maximum dimension of not more than 500 μm and a Knoop hardness of at least 100.

The tooth filler has such a consistency that it is sufficiently fluid that it can be easily modified at room temperature, for example by hand pressure alone. The material preferably has a paste-like composition.

The dental filler is preferably a mixture as described above, preferably containing a catalyst capable of effecting polymerization of the polymerizable prepolymer.

The dental filler can be applied to the tooth, for example in a hole in the tooth, and the polymerizable prepolymer can be polymerized so that the mixture forms a hard filling. This polymerization process is hereinafter referred to as mixture curing.

The urethane prepolymer is linear, contains isocyanate end groups and can be formed by reacting a diol with a diisocyanate to give a urethane prepolymer having the formula

OCNfR -NH-CO-O-Rg-O-OC-NH 2 R NCO I

wherein the diisocyanate has the formula OCN-R 1 -NCO and the diol HO-R 8 -OH, wherein R 1 and R 8 have the same meaning as above and n is an integer.

Reaction of the urethane prepolymer with an ethylenically unsaturated monomer that reacts with it results in a polymerizable prepolymer of the formula 1 3 r3

CH2 = C-X-BHfR -BH-CO-O-R.-O-OC-KH · »R, -NH-X-C-CH2 II

3,58065 wherein X is a divalent radical and R 1 is a hydrogen atom or a hydrocarbon group.

In order for the urethane prepolymer to have isocyanate end groups, it can be estimated that a molar excess of diisocyanate relative to diol must be used in the preparation of the prepolymer, the integer n value in the prepolymer depending on the diisocyanate to diol molar ratio used.

The formation of an isocyanate-terminated prepolymer can be aided by the use of catalysts known in the art to aid in the formation of polyurethane, e.g. tertiary amines and metal salts, e.g. stannous octoate and especially dibutyltin dilaurate.

The reaction between the diol and the diisocyanate can produce a viscous urethane polymer and especially when n is a large number, the prepolymer can be a solid and it is therefore desirable under these conditions that the reaction of the diol and the diisocyanate be performed in the presence of an inert diluent. Similarly, when the urethane prepolymer is highly viscous or solid, the reaction of the latter prepolymer with an ethylenically unsaturated monomer containing an isocyanate-reactive group to form a polymerizable prepolymer can preferably be performed in the presence of an inert diluent. The diluent must be substantially free of groups that react with the isocyanate groups, at least to the extent that the diluent does not interfere with the formation of the prepolymer. The diluent could be the liquid, ethylenically unsaturated monomer that copolymerizes with the prepolymer.

When the polymerizable prepolymer of structure II is prepared in an inert diluent, the prepolymer can be separated from the diluent, for example, by evaporating the diluent or adding an insoluble substance to the polymerizable prepolymer.

In order to have a higher strength and modulus and a higher shrinkage resistance as a filler made by vulcanizing a tooth filling mixture, it is recommended that the urethane prepolymer be formed of a polyisocyanate and a polyfunctional compound having at least one and preferably both a cyclic aromatic group, preferably an aromatic group. the urethane prepolymer of the isocyanate-reactive groups in the chain is formed from a diol and a diisocyanate having the structures HO-R 9 -OH and OCN-R 2 NCO, respectively, it is preferred that at least one of the divalent hydrocarbon radicals R 1 and R 2 is an internal cyclic aromatic group, preferably .

When it is desired to obtain a dental filler having a particularly high strength 1a modulus and shrinkage resistance, it is recommended that the polymerizable prepolymer in the dental filling composition 4,58065 has structure II in which R 1, R 2, R 2 and X have the same meaning as above, n is an integer 1 -20, at least one of the groups R2 and R2 contains at least one cyclic group in the prepolymer chain, the chain containing up to 30 carbon atoms between adjacent cyclic groups and when higher strength is desired, up to 20 and preferably up to 12 carbon atoms, and when n is 1 or only R? contains at least one cyclic group in the chain, the chain has at most 30 and preferably at most 20 and most preferably at most 12 carbon atoms between the cyclic group in radical R2 and the nitrogen atom attached to the group X, due to ease of preparation and most preferably less than 5 * so · the molar ratio between the isocyanate groups in the diisocyanate or mixture thereof and the hydroxyl groups in the diol or mixture thereof from which the isocyanate-terminated prepolymer is prepared is preferably 1.1: 1 or greater, and most preferably 1.2 : 1 or greater

Preferably, the value of n in the urethane prepolymer is not greater than 3 »i.e. the molar ratio between the isocyanate groups in the diisocyanate or mixture thereof and the hydroxyl groups in the diol or mixture thereof from which the urethane prepolymer is prepared is suitably 1.33: 1 or more.

Examples of diols containing cyclic groups which can be used to prepare the urethane prepolymer are, for example, cycloalkane diols, e.g. 1: 3 and 1: 4-cyclohexanediol and a diol having the structure

^. OH

in which case the group R2 in the urethane prepolymer has the structure OO ”‘ t} 0

Suitable diols from the mold include, for example, cycloalkanediol alkanols, e.g. cyclohexanedimethanol or cyclohexanediethanol and polycycloalkanediols, poly-cycloalkanediol alkanols, aryl dialkanolols and mechanized oxalates of alkylene oxides with aromatic compounds containing two phenols.

5 58065

Particularly preferred diols due to the desired properties of the fillers that can be prepared are diols having the structure

HOf CH - CH - 0> Ar 4 0 - CH - CH OH

II a I 1 D

R. Rc R., Rr- 4 5 4 5 so. oxyalkylated derivatives of phenolic compounds in which R and Rr are 4 hydrogen atoms or alkyl groups, e.g. methyl groups and Ar is a divalent aromatic group in which both free valencies are in aromatic carbon atoms and in which formulas a and b together are at most 8 and a is preferably at most b + 3 · In this case, the divalent group R2 has the structure CH - CH - O> Ar f O - CH - CH>.

St D

* * it H, Rc R Rr 4 5 4 5

Ar may be a mononuclear group, e.g. a phenylene group, a combined polynuclear group such as a naphthalene or anthracene group, or preferably has a structure wherein Y is a divalent bond, e.g. -O-, -SO 2 -, -SO- or -CH 2 or a group -CE2 substituted derivative, e.g.

CH, li • CH?

Preferably one of R 1 and R 2. is a hydrogen atom and the other is a methyl group or both R 1 and R 2. are hydrogen atoms, i.e. the diol can be prepared by reacting propylene oxide or ethylene oxide with a phenolic compound having the structure HO-Ar-OH, preferably H0 -o- ° H *

Preferably a + b is at most 4 · 6 58065

Examples of diols having no cyclic groups in the chain are, for example, ethylene glycol and propylene glycol, in which case R- has the structure -CH2-CH2 or -CH2-CH9-, butylene glycol, diethylene glycol and their derivatives in which one or more carbon atoms are replaced atoms or groups that do not react with the hydroxyl and isocyanate group.

Diisocyanates containing cyclic groups which can be used for the preparation of the urethane prepolymer are, for example, diisocyanates in which the free valence chain is provided with at least one aromatic group or at least one cycloaliphatic group or in which the free valence chain together contains at least one aromatic and cycloaliphatic group.

Cycloaliphatic diisocyanates are, for example, diisocyanates having the structure:

OCR NCO

x> · <y wherein -Ύ- is a divalent bond which may be, for example, -CHg- or a substituted derivative thereof, the -O-, -SO2-, -CO- and isocyanate groups are attached to the meta or para position relative to the Y group. A typical example is 4,4-dicyclohexylmethane diisocyanate.

Useful aromatic diisocyanates are, for example, 2: 4- or 2: 6-tolylene diisocyanates or mixtures thereof, in which case the divalent group has the structure CH, CH, O- or a combination of said structures.

Another suitable aromatic diisocyanate is one having the structure o ° »- (cB2) m hQk (οεΛ _ NC0> 7 58065 where M is an integer selected such that the urethane prepolymer derived therefrom preferably has up to 30 cyclic groups between them. A suitable diisocyanate having the latter structure is xylylene diisocyanar4 · 4 ·· '·

A particularly suitable aromatic diisocyanate is one having the structure: wherein Y is a divalent bond which may have the same meanings as indicated above and in which the isocyanate groups are attached at the meta or para position relative to the group Y. A preferred example is 4s4'-diisocyanatodiphenylmethane.

Hi-isocyanates that do not contain cyclic groups can be used in the preparation of the urethane prepolymer. Suitable such diisocyanates are, for example, tetramethylene diisocyanate, pentamethylene diisocyanate and hexamethylene diisocyanate, in which case the divalent group R 1 has the structure - (CH 2) 4 -, - or - (CH 2) g -,

The ethylenically unsaturated monomer reacted with the urethane prepolymer to produce a polymerizable prepolymer may have, for example, an isocyanate group or an isocyanate-reactive group, depending on whether the urethane prepolymer contains isocyanate groups or isocyanate-reactive groups, respectively.

The ethylenically unsaturated monomer which is reacted with the urethane prepolymer to produce a polymerizable prepolymer may be, for example, acrylic acid or a derivative thereof having the structure? 3

CH2 = C - C00H

having a hydrogen atom or a hydrocarbon group, for example, an alkyl group such as a methyl group. In this case, the group -X- in the polymerizable prepolymer II has the structure -C-

It is after the carbon dioxide has been removed from the reaction product originally formed.

8 58065

Other suitable ethylenically unsaturated monomers include, for example, hydroxyl group-containing monomers having the structure:

CH2 - C - COO - (CH2) p-OH

having a hydrogen atom, or a hydrocarbon group, e.g. an alkyl group such as a methyl group, and p is an integer of at least 2 and preferably just 2, or derivatives of said monomer in which one or more hydrogen atoms in the group - (CH 2 Jp-) are replaced by a hydrocarbon group, e.g. an alkyl group , such as methyl In this case, the group -X- in the polymerizable prepolymer has the structure -C00- (CH2) p-O-CO-.

Suitable examples are hydroxyethyl or hydroxypropyl acrylate or methacrylate prepared by reacting acrylic acid or methacrylic acid with ethylene oxide or propylene oxide, in which case the group X in the polymerizable prepolymer II has the structure -COO- (CH-C 1) -O-CO in which either both Rg and Ry are hydrogen atoms or one of Rg and Ry is a hydrogen atom and the other is a methyl group.

Other suitable isocyanate-reactive ethylenically unsaturated monomers include allyl alcohol, in which case the group X in the polymerizable prepolymer has the structure -CH 2 -O-CO-, and acrylamide and methacrylamide, in which case the group X in the polymerizable prepolymer X .

As discussed above, at least $ 50 of filler particles must have a maximum dimension of no more than 1000 microns. This means that the maximum dimension of the particles in any direction must not exceed 1000 microns. Thus, when the filler is in the form of spheres, at least 50% of the spheres should be at most 1000 microns in diameter. When the filler is in the form of fibers, at least $ 50 of the fibers should be no more than 1,000 microns in length. Preferably, the maximum dimension of substantially all of the filler particles is at most 1000 microns.

The blending of the filler into the polymerizable prepolymer generally becomes easier as the size of the filler particles decreases. The recommended maximum dimension of the particles in the filler is determined by the shape of the filler. Thus, when the filler is in the form of fibers, the maximum dimension of the fibers is preferably at most 500 microns and more preferably at most 100 microns. On the other hand, when the filler is in the form of spheres or sheets or is irregular in shape, the maximum dimension of the particles in the filler is preferably at most 500 microns and most preferably between 1 and 100 microns. In order for a hard tooth filling to be made by vulcanizing the it is desirable that the 5 58065 filler particles have a Knoop hardness of at least 100. In general, the higher the hardness of the filler particles in the mixture, the higher the hardness of the tooth-fill mass produced by vulcanizing the mixture and therefore it is recommended that the filler the hardness is at least 300 and preferably at least 500 * In general, inorganic fillers have the required hardness and in particular the recommended hardness.

In order for the tooth filling mass prepared by vulcanizing the dental filler to have the appearance of a natural tooth, it is recommended to use a translucent filler.

For example, a dental filler composition may contain $ 10-90 filler by weight of the composition, although in order to have particularly desirable abrasion resistance, hardness, low shrinkage in vulcanization, and low coefficient of thermal expansion, the dental fillings preferably contain 30-80 and most preferably 60-80. Mixtures of different excipients can also be used.

For example, the filler may be in the form of spheres, sheets, fibers or crystallizations, or it may be irregular in shape. Suitable fillers are, for example, apatite, soda glass, quartz, silica gel, borosilicate glass, synthetic sapphire (alumina) or metal fibers.

Mixing the polymerizable prepolymer with the filler to form a dental filler mixture can be accomplished by mixing the prepolymer and filler together. However, since the polymerizable prepolymer optionally together with the copolymerizable monomer can be viscous and thus difficult to mix with the filler to provide adequate mixing, the polymerizable prepolymer optionally together with the copolymerizable monomer can be easily diluted with a suitable diluent to reduce viscosity. Once the mixing has been completed, the diluent can be removed, for example, by evaporation. The diluent may suitably be a copolymerizable, ethylenically unsaturated monomer which, if desired, is completely removed after mixing has taken place, or when the tooth filling mixture is to contain a copolymerizable, ethylenically unsaturated monomer, the amount of monomer is then reduced to the desired level.

In order to prepare a tooth filling in which the filler adheres particularly well to the vulcanized polymerizable prepolymer in the filling mass, it is highly recommended that the filler be treated with a mating agent capable of reacting with both the filler and the polymerizable prepolymer before the filler and polymerizable prepolymer are mixed. The mating agent should have an effect that increases the strength of the bond between the filler in the filler and the vulcanized polymerizable prepolymer.

58065

Suitable mating agents for use with glass include silanes, e.g., Y-methacryloxypropyltrimethoxysilane, Y-aminopropyltriethoxysilane, and Y-glycidoxypropyltrimethoxysilane.

As discussed above, the dentifrice composition may contain a liquid ethylenically unsaturated monomer that copolymerizes in the polymerizable prepolymer lance and should contain such a monomer when the polymerizable prepolymer is solid in order for the dentifrice composition to be liquid and especially to have a pasty composition.

The amount of such ethylenically unsaturated monomer used is hopefully just sufficient to provide the desired fluidity to the tooth filling mixture. Since the use of such a monomer can lead to a reduction in the strength of the filler mass made from the blend, it is recommended that no more than 100 ethylenically unsaturated monomers based on the weight of the polymerizable prepolymer be used as the filler blend, and most preferably no more than 50.

Suitable liquid copolymerizable ethylenically unsaturated monomers, the polymers of which must be water-insoluble, include vinyl monomers, e.g. vinyl esters and acrylic and methacrylic acids. The monomers must be non-toxic.

Suitable vinyl esters are, for example, vinyl acetate, esters of acrylic acid of the formula CH2 = CH-C00R8, in which R1 is an alkylaryl, alkaryl, aralkyl or cycloalkyl group. The group R 1 may be, for example, an alkyl group having 1 to 20 and preferably 1 to 10 carbon atoms. Separate vinyl esters which may be mentioned are, for example, methyl acrylate, ethyl acrylate, n- and isopropyl acrylates and n-, iso- and tert-hutyl acrylates.

Other suitable vinyl esters are, for example, esters of the formula CH2 = C (R1) COORg, where Ry can be an alkyl group, e.g. a methyl group. In the ester of the formula CH2 = C (Ry) COORg, the groups Rg and Ry may be the same or different groups. Separate vinyl esters which may be mentioned are, for example, methyl methacrylate, ethyl methacrylate, n- and isopropyl methacrylate and n-, iso- and tert. -butyylimetakrylaatti.

Mixtures of acids and esters can also be used.

Polyfunctional vinyl monomers, i.e. monomers containing two or more vinyl groups are also suitable. Suitable monomers include, for example, glycol dimethacrylate, dialkyl phthalate and trialkyl cyanurate.

The dental filler composition of the present invention can be embedded in the dental filler to the desired shape and then vulcanized to form an image filling by polymerizing the polymerizable prepolymer, optionally together with an ethylenically unsaturated monomer copolymerizable therewith.

11 58065 - ~ Vulcanization of the mixture to produce tooth filling mass can be aided by a catalyst. It is desirable that the catalyst be able to vulcanize the mixture at a relatively low temperature, e.g., at or near ambient temperature, because the use of elevated temperatures can result in an unpleasant sensation in the patient being treated. Suitable catalysts capable of effecting vulcanization at a relatively low temperature are, for example, a mixture of peroxide and an accelerator, e.g. a peroxide and an amine, such as a mixture of benzoyl peroxide and N, N-dimethyl-p-toluidene. Other catalysts are a mixture of peroxide and a cobalt accelerator, such as methyl ethyl ketone peroxide and a mixture of cobalt octoate, cobalt naphthenate or cobalt naphthenate and dimethylaniline.

When the catalyst used is capable of effecting vulcanization of the mixture at a relatively low temperature, it is desirable that the catalyst be mixed into the dental composition just prior to use of the composition, otherwise an undesirable amount of vulcanization may occur before the mixture is shaped to the desired tooth filling.

The amount of catalyst used is generally between 0.01 and 20 $ of catalyst based on the weight of the polymerizable substance in the dental care composition, i. $ 0.01-20 $ by weight of polymerizable prepolymer plus copolymerizable monomer. Smaller or larger amounts of catalyst may be used if desired, although 0.1-10 p-tfo catalyst is recommended. It is most recommended to use 0.5-5 p-fo catalyst.

The catalyst used may be radiation activatable and in accordance with a preferred aspect of the invention there is provided the preparation of a dentifrice composition comprising a photosensitive catalyst comprising (a) at least one photosensitizer selected from the group consisting of fluorenone, substituted derivatives thereof and X-diketones having the structure :

A - C - C - A

ff rr o o wherein the groups A, which may be the same or different, are hydrocarbon groups or substituted hydrocarbon groups, and (b) at least one reducing agent capable of reducing the photosensitizer when in the excited state.

The dental compositions of this invention containing a photosensitive catalyst can be vulcanized by irradiating the mixture with ultraviolet radiation, i. with radiation having a wavelength between nm 2} 0 jvl and 400 ipu. The mixtures can also be vulcanized by irradiation with visible radiation and in particular with visible radiation

The mixtures can also be vulcanized by irradiation with visible radiation, and in particular with visible radiation having a wavelength of QQg, 400-500 ipu. Alternatively, a mixture of ultraviolet and visible radiation may be used.

in an α-diketone having the above structure, the groups A, when they are hydrocarbon groups, may be, for example, aliphatic groups such as alkyl groups having 1 to 10 carbon atoms, aromatic groups such as phenyl groups; cycloaliphatic groups such as cyclohexyl groups such as tolyl groups. Alternatively, the groups A may together form a divalent radical such that in the photosensitizer the groups A together with the carbonyl groups form a cyclic structure. For example, the groups A may form a divalent aliphatic group or they may form an aromatic group and in particular may form a fused aromatic ring system.

Suitable α-diketones are biacetyl having the structure CH_ - C - C - CH, 3 it n 3 0 · 0 benzyl, having the structure

OitG

α-naphthyl having the structure S-n "8 β-naphthyl having the structure

^ 1 CP

acenaphthacene of structure 5 80 65 13 or rabbit ricinone of structure

When the groups A are substituted and hydrocarbon groups, the substituent group or groups must not lead to a substantial inhibition of the polymerization of the polymerizable material. * Examples of photosensitizers in which the groups A are substituted hydrocarbon groups are ρ, ρ'-dimethoxybenzyl and p, pT-diklooribensiili.

A particularly recommended photosensitizer is gasoline.

The photosensitizer may be present in the dental filler, for example, in a concentration of 0.01 to 10 p-$ by weight of the polymerizable substance in the mixture, although concentrations outside this range may also be used if desired. The photosensitizer is preferably present in a concentration of between 0.5 and 5% by weight of the polymerizable substance in the mixture.

The reducing agent present in the photosensitive catalyst must be able to reduce the photosensitizer when in the Tried state. The reducing agent should have little or no anti-polymerization effect. Whether or not a reducing agent has a inhibitory effect can be determined by a simple experiment, for example, by polymerizing the polymerizable material in the mixture by thermal initiation alone and in the presence of the desired concentrated reducing agent and comparing the polymerization rates when reducing.

the active substance is and is not present. R

*

Suitable reducing agents include compounds having the structure RMR, wherein M is a group Vb element of the Periodic Table of the Elements and the groups R, which may be the same or different, are hydrogen atoms, hydrocarbon groups, substituted hydrocarbon groups or groups wherein two units R together with element M forms a cyclic ring system, with at most two units R being hydrogen atoms and in which the element M is not directly attached to the aromatic group.

Said periodic table of elements is that which F.A. Cotton and G. Wilkinson have published in Advanced Inorganic Chemistry, second edition (Interscience 1966).

h 58065

The element M in the reducing agent may be, for example, phosphorus or, preferably, nitrogen. If desired, M may be arsenic or antimony.

The reducing agent may be primary, secondary or tertiary, i.

in the structure ^

R - M - R

two, one or none of the units R may be hydrogen atoms. The reducing agent may be, for example, a primary, secondary or tertiary amine or phosphine.

One or more of the groups R may be a hydrocarbon group. The hydrocarbon group may be an alkyl, cycloalkyl or aralkyl group. Most preferably, the group R may be an alkyl group having 1 to 10 carbon atoms.

Examples of suitable reducing agents in which one or more of the units R is a hydrocarbon group are propylamine, hutylamine, pentylamine, hexylamine, dimethylamine, diethylamine, dipropylamine, tributylamine triphenylamine, dipentylamine, trimethylamine, triethylamine, triethylamine, triethylamine, triethylamine, triethylamine, amines, such as 0H, "HMe".

J-ο il £

It is to be understood that throughout this specification, when referring to specific examples of suitable reducing agents in which the element M is a nitrogen atom, it is intended to include those specific examples in which the element K is phosphorus, arsenic or antimony.

One or more of the units R may be a substituted hydrocarbon group and in particular the hydrocarbon group may have a substituent having the structure "E2 wherein M is an element of group Vb of the Periodic Table of the Elements and the unit R 1 is, for example, an alkylene chain and units R 1 which may be the same or different , doors for example hydrogen atoms or hydrocarbon groups.

Examples of reducing agents having the structure f R - M - R in which at least one of the units R is a substituted hydrocarbon group are diamines having the structure __R2 - (CH2) n - N H2 ®2 in which n is an integer of at least two and the groups R 1, which may be the same or different, are hydrogen atoms or hydrocarbon groups, especially alkyl groups. The reducing agent may be, for example, ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine or hexamethylenediamine or their N-hydrocarbon and in particular N-alkyl derivatives.

15 5 80 65

Other suitable reducing agents are derivatives having the structure R 2 / E 2 E> - (- 2> n in which one or more hydrogen atoms in the -CH 2 units have been replaced by - groups, in particular -NH 2, -.

Examples of reducing agents in which M forms part of the cyclic ring system are piperidine and the N-hydrocarbon and especially If alkyl derivatives of piperidine. Other reducing agents include riallylamine, (allyl) - (O-O-O (M-Callyyl)), allylthiourea and soluble salts of aromatic sulfinic acids.

The concentration of the reducing agent may suitably be in the ranges set out above for the photosensitizer. The reducing agent is preferably present in a concentration of 1-5 p- $ by weight of the polymerizable substance in the dental preparation.

The invention will now be illustrated by the following examples, in which all parts are by weight.

Example 1,552 parts of the condensate obtained by reacting 2: 2-bis- (p-hydroxyphenyl) propane and propylene oxide in a molar ratio of 1: 2 were heated to melt the condensate and stirred under reduced pressure to degas the condensate.

500 parts of 4: 4'-diisocyanatodiphenylmethane were heated in the same manner, stirred and degassed separately. The condensate and diisocyanate (molar ratio diisocyanate: condensate 2: 1) were then mixed together, and 556 parts of methyl methacrylate dried over calcium hydride were added to the mixture, followed by an additional 0.14 part of dihutyltin dilaurate. The mixture was cooled in an ice bath to control the exotherm produced by the urethane prepolymer formation reaction so that the temperature did not rise above 55 ° C. Stirring was continued for 1 l / 2 hours after the end of the exotherm.

260 parts of 2- (hydroxyethyl) methacrylate, previously distilled and degassed, were then added and the resulting mixture was stirred for 1 1/2 hours to form an ethylenically unsaturated polymerizable prepolymer.

A mixture of the polymerizable prepolymer and methyl methacrylate prepared above in 60 parts by weight was mixed with 180 parts of glass spheres (Ballotini J000 CPO 1. Plastichem Lts.), 80 of which had a diameter of between 4 and 44 μm.

The mixture was then stirred, more methyl methacrylate was added to facilitate stirring, and then 6 parts of a catalyst solution formed by dissolving 2 parts of gasoline in 4 parts of dimethylaminoethyl 16,58065 methacrylate and 4 parts of methyl methacrylate were added. After stirring for 15 minutes, the pressure was reduced and the methyl methacrylate added to facilitate stirring was removed by evaporation.

The pasty mixture was then drawn into a cylindrical glass mold and exposed to blue lamp radiation for 15 minutes to vulcanize the mixture.

The vulcanized material had the following properties: -2

Compression strength 178 N mm

Compression module 3690 N mm

Rpckwell hardness 171 scale H

Bending module I45OO N mm

Water absorption 0.75 p- $ (63 days immersion in 37 ° C water)

Example 2

The procedure of Example 1 was followed except that 30 parts of a mixture of ethylenically unsaturated polymerizable prepolymer and methyl methacrylate and 3 parts of catalyst solution and 60 parts of glass fibers ground in a hammer mill with dimensions of 10x200 microns (Glass Fibres) were used instead of glass spheres. Before the glass fibers were mixed with the other components of the mixture, they were surface-treated with Y-methacryloxypropyltrimethoxysilane by adding 100 parts of glass fiber preheated to 400 ° C and allowed to cool in a desiccator to a solution of 1 part of Y-methacryloxypropyltrimethoxy evaporating the methanol, sieving the fibers through a 62 mesh screen, and finally heating the fibers to 140 ° C to vulcanize the silane.

The vulcanized material had the following properties: _2

Compressive strength 201 N mm - 2

Compression modulus 3 ^ 40 N mm

Rpckwell hardness 82 scale B

Rockwell hardness 168 scale H

Abrasion resistance 0.03 mg mm

Example 3

The procedure of Example 1 was followed except that 15 parts of a mixture of ethylenically unsaturated polymerizable prepolymer and methyl methacrylate were used.

The vulcanized material had the following properties: _2

Compressive strength 157 »6 N mm _2

Compression module 3050 N mm

Rockwell hardness 81 scale B

Rockwell hardness 170 scale H

-2

Abrasion resistance 0.007 mg mm 17 58065

Linear coefficient of thermal expansion 33.7 ppm at 40 ° C

Example 4 500 g of freshly distilled 4 ', 4' - (ii) isocyanate diphenylmethane were washed with 300 ml of methylene chloride in a 5-liter flanged neck flask purged with nitrogen gas. The flask was then equipped with a glass anchor stirrer, a nitrogen purge, a water condenser and a thermometer.

352 s of molten condensate obtained by condensing 2,2-bis (p-hydroxydiphenol) propane and propylene oxide and 0.15 g of dibutyltin dilaurate were weighed into a 1 liter dropping funnel purged with nitrogen gas. 200 ml of methylene chloride was added to the dropping funnel to prevent the condensate from becoming solid.

The dropping funnel was then placed above the flask and its contents were added dropwise to the flask over 45 minutes, after which the reaction was allowed to proceed for about 45 minutes, adding 300 g of hydroxyethyl methacrylate along with 0.15 g of dibutyltin dilaurate over 3 minutes. The temperature of the contents of the flask rose and after falling, the flask was heated in a water bath (refluxing methylene chloride) and the contents were stirred under a nitrogen purge until the infrared spectrum of the resulting product indicated that only traces of isocyanate groups were present (ca. 3 days).

The water bath was then removed and methanol was added to the stirred contents of the flask, causing the polymerizable polymer therein to separate. The contents of the flask were allowed to settle and then the methanol layer was sucked off and discarded. The methanol wash was repeated as above several times until a clear methanol layer was obtained. The polymerizable prepolymer in the flask was then dried at room temperature under vacuum until a dry foam was obtained. The foam was then crushed and dried to remove residual methanol.

In the absence of blue light, 13.37 parts of polymerizable prepolymer powder was dissolved in 10.94 parts of ethylene glycol dimethacrylate, and then 0.625 parts of dimethylaminoethyl methacrylate was added to the solution, and then 0.0625 parts of camphorquinone was added to the solution. 75 parts of a borosilicate glass powder having a particle size of less than 53 and coated with 1β-β-methacryloxypropyltrimethoxysilane were mixed into the mixture, and the resulting liquid paste was passed through a roller through which gas was removed.

Cylindrical pasta samples 3 mm in diameter and 2.5 mm in length in polytetrafluoroethylene molds were irradiated with light for 2 minutes using a light source equipped with 18-inch fiber optics. The vulcanized samples were removed from the molds and stored under water at 37 ° C and tested after 1 hour, 24 hours and 1 week. The results are shown in the table below.

18 58065

Table

Time Wed s g gpuri s tu sluj new Average tensile strength Rockwell (H mm) (N mm) hardness (scale E) 1 hour 259 42 24 hours 274 45 115 1 week JOI 46

Example 5 2.585 parts of the polymerizable prepolymer prepared as described in Example 4 were dissolved in 2.115 parts of ethylene glycol dimethacrylate, and 0.1 part of fluorenone and 0.2 part of dimethylaminoethyl methacrylate were added to the solution. 7.5 parts of borosilicate glass powder (as in Example 4, but coated with 2 .mu.l of silane) were mixed with the resin while degassing, and then thick samples of the resulting paste were vulcanized as in Example 4 for 100 minutes using a low-intensity mercury lamp filtered to send 45 radiation. The depth of vulcanization was 1.5 mm.

Example 6

The paste was prepared and vulcanized as in Example 5 except that α-naphthol was used instead of fluorenone. The vulcanization depth was 2.5 mm. Examples 7-12 6.7 parts of the polymerizable prepolymer prepared as described in Example 4 were dissolved in 5.3 parts of methyl methacrylate, and 0.2 part of a solution of fluorenone (0.1 part) in dimethylaminoethyl methacrylate (4 parts) was added. 15 parts of the filler were mixed together and the resulting paste was drawn into a 6 mm diameter glass tube. Samples were cured by irradiation with light from a fluorescent tube for 30 minutes. The vulcanized samples were cut to a length of 12 mm and their compressive strengths were determined.

Example Filler Compressive strength No. (N mm “2) 7 Borosilicate glass (less than 53 microns) 178 8 Glass plates (dia. 1/32") 98 9 Ballotini glass spheres 158 10 Quartz (less than 53 microns) 158 11 Silica gel spheres (less than 53 microns) ) 120 12 Glass fibers ground in a hammer mill 202 (soda glass - diameter 10 microns, length 200 microns) 58065 19

Example 13 5.5 parts of a polymerizable prepolymer such as Example 4 was dissolved in 4.5 parts of ethylene glycol dimethacrylate and 0.025 part of N, N-dimethyl-p-toluidine was added to the solution.

0.3 part of the mixture was mixed for a few seconds with 0.7 part of the coated filler using a spatula. The coated filler was a coated borosilicate glass powder having a particle size of less than 53 microns and obtained by coating 23.33 g of ground glass successively with 0.23 parts of Y-methacryloxypropyltrimethoxysilane and 0.03 parts of benzoyl peroxide from methylene chloride.

The resulting paste was filled into 3 mm x 3 m cylindrical molds which were allowed to stand for several hours, after which the hard samples were removed and tested. The compressive strength of the hard material was 160 N n and the diameter compressive was 30 N mm '.

Example 14 33.33 parts of the polymerizable prepolymer prepared as described in Example 1 were dissolved in 16.66 parts of methyl methacrylate and 170 parts of Ballotin glass spheres (FP01 3000) having an average diameter of 4.4 microns were mixed into the solution. 5 parts of a solution of dimethylaminoethyl methacrylate (40 fo) and benzyl (20 ′ fo) in methyl methacrylate (40 fo) were added and the mixture was heated. Excess methyl methacrylate was added and then the mixture was stirred for 15 minutes, after which the excess methyl methacrylate was removed in vacuo.

The resulting paste was filled with 3 conical holes drilled in the teeth of a hare dog and vulcanized in situ using a light source equipped with an 18-inch fiber optic. The sites have remained in the teeth for 26 months and show no signs of major mechanical damage or free movement in the holes.

Examples 15-22 A polymerizable prepolymer was prepared as described in Example 4. In the absence of blue light, 3 * 1 g of the prepolymer was dissolved in 2.54 g of monomer (see) and 0.24 g of dimethylaminoethyl methacrylate, followed by 0.12 g of benzyl. 14 g of ground borosilicate glass having a particle size of less than 53 microns and coated with 2 .mu.l of Y-methacryloxypropyltrimethoxysilane were mixed into the mixture (such that the filler was 70 .mu.l of the mixture) and the resulting paste was passed through a roller. during which time the gas escaped.

Cylindrical paste samples 3 mm in diameter and 21/2 mm in length were vulcanized in polytetrafluoroethylene molds by irradiation for 1 hour from a 12-inch end from Thom sealing beam lamps. Samples were removed from the molds after 1 hour and tested for compressive strength and hardness.

20 58065

Example No. Monomer 15 Methylene methacrylate 16 Methacrylic acid 17 Hydroxyethyl methacrylate 18 Vinyl toluene 19 Styrene 20 Triethylene glycol dimethacrylate 21 Ethylene glycol dimethacrylate 22 Allyl methacrylate

Example No. Compressive strength (Nmm ~ 2) Rockwell hardness (scale H) 15 173 56 16 172 54 17 164 48 18 166 50 19 165 22 20 179 70 21 184 85 22 155 52

Example 25 A. The procedure of Example 21 was repeated except that after 1 hour of irradiation, the sample was removed from the mold and allowed to stand for 2 days before testing.

B. For comparison, the above Deva procedure was repeated using a different polymerizable prepolymer. The prepolymer was prepared as follows: Freshly distilled 2,4-toluene diisocyanate was washed in a flask with methylene chloride, and a mixture of 2,5-propane bis (5- (4-phenoxy) -1,2-hydroxypropane-1-methacrylate and dibutyltin dilaurate was added dropwise to the flask. The reaction was allowed to proceed until infrared analysis of the mixture indicated that only traces of isocyanate groups were present, methanol was added to the flask to cause separation of the resulting prepolymer, which was then dried and finally crushed.

C. For comparison purposes, the procedure of Am was repeated again using the prepolymer prepared according to B except that phenyl isocyanate was used instead of 2,4-toluene diisocyanate.

D. For comparison, the procedure of step A was repeated using the prepolymer prepared as in step B, but using anisidene diisocyanate instead of 2,4-toluene isocyanate.

E. In another comparative experiment, the procedure of step A was repeated again using a prepolymer prepared as in step B but using 21,58065 of 4,4'-diisocyanate diphenylmethane instead of 2,4-toluene diisocyanate.

Compressive strength Tensile strength Rockwell- Curing depth -2 v -2. hardness (mm) 100 0 second consumption mm) (Nmm) (scale H) tua A 197 37 105 4.7 B 178 32 88 C 149 28 sample fragmented D * E 201 34 96 3.1 ^ The material appeared to vulcanize very poorly and not testable samples obtained.

Example 24 A. 35.2 g (0.1 mol) of oxypropylated Bisphenol A was dissolved in about 100 g of methylene chloride and the resulting solution was added dropwise to a solution of 33.6 g (0.2 mol) of hexamethylene diisocyanate. and 100 g of methylene chloride under nitrogen. 4 drops of dibutyltin dialurate (available under the trademark Mellite 12 ") were added as a catalyst. The mixture was stirred under a stream of nitrogen for 1 hour, then heated to reflux for 9 hours. The mixture was then cooled and a solution of 26 g (0.2 moles) of 2-hydroxy ethyl methacrylate in 100 g of methylene chloride was added, after which the mixture was heated under reflux for 3 hours, then the mixture was cooled and the resulting polymerizable prepolymer was isolated as a viscous resin by treating the mixture with petroleum ether, followed by removal of the remaining solution on a rotary evaporator.

The following dental filling preparation was prepared from viscous resin:

Viscous resin 13.37 g ethylene glycol dimethacrylate 10.94 g camphorquinone 0.0625 g dimethylaminoethyl methacrylate 0.625 gx) borosilicate glass powder 75 g (diameter <53 microns) x) treated with 1% by weight si county a (rf 74) t <^ <mu.

To prepare the mixture, ethylene glycol dimethacrylate was weighed into a 250 ml container containing viscous resin. The mixture was stirred until the resin was dissolved, after which the amine and camphorquinone were added with stirring. After complete dissolution of the catalyst, the glass x) A 15 / w / 2lv G.E. quartz lamp ^ 58065 The powder filler was mixed with the preparation to obtain a paste, which was then placed in a vacuum dome where it was degassed for about 2 minutes.

Samples of the degassed formulation were poured into a polytetrafluoroethylene mold, 3 mm long and 3 mm in diameter, and then irradiated for 2 minutes with a standard lamp with 18-inch fiberglass optics and then immersed in 37 ° C water for 24 hours. and then experimented. The characteristics were as follows: -2

Compressive strength - average 323.4 N mm -2 - maximum 341.0 N mm - 2

Tensile strength - average 55.4 N mm in diameter _2 direction - maximum 59.4 N mm

Depth of curing (after 1 minute) 6 mm B. The above procedure was repeated for comparison, but using 4,4'-diisocyanatodiphenylmethane diisocyanate (0.2 moles) they see the base of the diisocyanate diisocyanate. .

C-G For comparison, 3 mm x 3 mm samples of conventional dental filler were prepared in a normal manner and tested.

C. Prestige dental filling product (Lee Pharmaceuticals) D. Cosmic dental filling product (De Trev) E. HL-72 dental filling product (Lee Pharmaceuticals) F. Conventional amalgam G. Encapsulated conventional amalgam

Property A B C D E F G

Compressive strength _2 323.4 260 298 267 253 266 350 (average) (H mm Ί

Tensile strength 9 (average) (N mm ”^) 55.4 46.0 45.0 48.0 41.0 43.0 49.0

Depth of curing after 1 minute (mm) 63 - - - -

The handling properties of preparations A and B were also compared. The polymerizable prepolymer in Preparation A is a viscose resin, while in Preparation B it is solid. Thus, Preparation A, which contains 75% by weight of excipient, is less tough and easier to handle than Preparation B. Alternatively, Formulation A is easier than Formulation B to fill 80% by weight or more of the filler, resulting in improved wear resistance and improved hardness of the fillings derived from the formulations.

Example 25 52.4 g (0.2 moles) of dicyclohexylmethane diisocyanate 4.4, 23 5 8 0 6 5 were placed in a flask with 30 ml of dry methylene chloride under a stream of nitrogen. 35.2 g (0.1 mol) of oxypropylated Bisphenol A was dissolved in 50 ml of dry methylene chloride and the solution was washed in a dropping funnel with 20 ml of dry methylene chloride. 10 drops of dibutyltin dialurate (Mellite 12) were added to the solution in a dropping funnel.

The mixture in the flask was heated until the methylene chloride slowly recovered and then the solution in the funnel was added dropwise with stirring over 1 hour. Stirring was continued for about 1 1/2 hours, after which 26 g (0.2 moles) of hydroxyethyl methacrylate and 10 drops of dibutyltin dialurate (Mellite 12) were added via addition funnel over 15 minutes. The mixture was stirred for a further 3 hours and then allowed to stand for about 70 hours. Infrared analysis of the mixture showed traces of isocyanate and the mixture was allowed to stand for a further 48 hours. The resulting polymerizable prepolymer was isolated as a solid by treating the mixture with petroleum ether followed by removal of the remaining solution on a rotary evaporator.

As described, a dental filling preparation of this solid prepolymer was prepared according to the composition described in Example 24. The samples were cured as also described in Example 24.

The prepolymerized paste had good flow properties and the cured material was very translucent. The curing depth reached in one minute was 6.1 mm and after the cured material was kept immersed in 37 ° C water for 24 hours (Example 24), its compressive strength (average) was 264.2 ° N / mm 2 and its tensile strength (average) 41 .7 N / mmz.

Example 26

A dental filling preparation was prepared and cured as described in Example 25 except that 34.8 g (0.2 moles) of 2,4-toluene diisocyanate was used instead of dicyclohexylmethane. The paste had good flow properties and the cured material was translucent. The curing depth in 1 minute was 5.5 mm. After being immersed in 37 ° C water for 24 hours, the material had a compressive strength (average) of 290.65 N / mm and a tensile strength (average) of 47.6 N / mm 2.

Claims (3)

A dental filler comprising a mixture of a binder and a filler, characterized in that the binder is a polymerizable material comprising a) a polymerizable prepolymer containing at least two ethylenically unsaturated groups and which is a reaction product of a urethane prepolymer and an acrylate ester of formula R_ Η / 'R', 3, 6 7 CH 2 = C-CO-O-CH-CH-OH where R 1 is hydrogen or methyl and R 8 and R 2 represent hydrogen or one of them is hydrogen and the other methyl, wherein the urethane prepolymer is a reaction product di an isocyanate of the formula OCN-R 1 -NCO and a diol of the formula H 0 -R 2 -OH, in which R 1 is a cycloaliphatic, aromatic or aliphatic group and R 8 is a residue of a condensate between an alkylene oxide and a compound containing phenol groups, and b ) up to 100% by weight of vinyl monomer, based on the amount of polymerizable prepolymer, and that the filler is 60-90% by weight of the dental filler and that it is inert, inorganic, finely divided. filler of which at least 50%. the particles have a maximum dimension of not more than 500 μm and a Knoop hardness of not less than 100. Dental filler according to Claim 1, characterized in that the polymerizable material contains a polymerization catalyst. 2 „58065 Dental filler according to claim 2, characterized in that the catalyst is a photosensitive catalyst comprising a) a photosensitizer which is fluorenone, biacetyl, benzyl, o (- or β-naphthyl, acenaphthene quinone or camphorquinone), and b) a reducing agent which is primary, secondary or tertiary amine or phosphine. Dental filler according to claims 1 and 2, characterized in that the polymerizable material comprises a) a polymerizable prepolymer which is a reaction product of a urethane prepolymer and 2-hydroxyethyl methacrylate, the urethane prepolymer being a reaction product of a diisocyanate diisocyanate diisocyanate diisocyanate , hexamethylene diisocyanate, 1 ', U'-dicyclohexylmethane diisocyanate, 2, U-tolylene diisocyanate or 2,6-tolylene diisocyanate, and a diol prepared by carrying 2,2-bis- (p-hydroxyphenyl ) propane to react with propylene oxide in a molar ratio of 1: 2, 5 58065 b) not more than 100% by weight, based on the vinyl monomer of the polymerizable prepolymer, which is an ester of the formula CE 2 = C (R 2) C An alkyl group having 1 to 10 carbon atoms, or the ester is ethylene glycol dimethacrylate or triethylene glycol dimethacrylate, and c) 0.01 to 10% by weight, based on the amount of polymerizable material, of a photosensitive k an analyzer comprising a photosensitizer which is fluorenone, benzyl, camphorquinone or <X-naphthyl and a reducing agent which is dimethylaminoethyl methacrylate, and that βθ-90 by weight, based on the amount of dental filler, is a transparent, inert, inorganic, inorganic, inorganic, inorganic substantially all particles have a maximum dimension of at most 100 ^ un and a Knoop hardness of at least 300. 26 5 80 65