NL8102128A - POLYMERISABLE MIXTURE FOR DENTAL USE AND METHOD FOR PREPARATION THEREOF. - Google Patents

Description

·. * - A

_________ ___________ \ ^ '"? 7 | vo 1892 ·. \

14ME981 I

Polymerizable mixture for dental use, as well as a method of preparation thereof

The invention generally relates to polymerizable mixtures for dental use and more particularly to such mixtures which are capable of curing at high speed to form a polymerization product in which the amount of insoluble component is relatively high. The invention also relates to a method for preparing the said mixtures.

Polymerizable dental mixtures, based on the use of methacrylate monamers, for example the reaction product of the bisglycidyl ether of bisphenol-A and methaeryl acid (hereinafter referred to as BIS-GMA), are widely used as fillings, dimples and crevices sealants and are advantageously adapted for a wide variety of dental repair techniques. Such mixtures include, for example, one or more methacrylate monamers and at least one component of a free-radical (redox) polymerization system for said monomer (s). Usually, the monomer mixture thus composed comprises the peroxy-type (oxidant) catalyst, which is contacted later with the reducing agent (reductant) shortly before dental use. Upon contact of the oxidant mixture with the reductant mixture, which mixtures are usually conveniently supplied as pastes, polymerization occurs, resulting in the formation of a polymerization product with physical properties necessary to maintain good structural integrity within the oral cavity, for example, high compression strength, high insolubles, etc. The latter condition is highly desirable to minimize the leaching of vital ingredients and the resulting deterioration of the polymerization product.

Rapid and complete curing are therefore highly desirable objectives. To some extent, increasing the catalyst concentration enhances the cure speed; however, mutually relative increases in the degree of curing are not necessarily obtained.

8102128 _ - ~ 2- "4 **** - * 9

In fact, it does. often the case where large catalyst concentrations adversely affect the degree of curing, resulting in a relatively greater percentage of soluble and leachable components in the final polymerization product. In addition, larger amounts of peroxide catalyst increase the possibility of prepolymerization of methacrylate comonomer, that is, prior to contact with the reducing agent, often requiring the use of adjuvants, often in unusually large amounts, which have a stabilizing or polymerization retarding effect. However, such retarding effects inevitably show to some extent during the contact between monomer, oxidant and reductant, the. curing speed and inevitably the degree of curing are reduced.

It is a first object of the invention. providing polymerizable dental mixtures in which the aforementioned and related drawbacks are eliminated or at least substantially mitigated.

Another object of. The invention is to provide polymerizable dental mixtures capable of a high cure speed, thereby compounding a polymerization product having a relatively high insoluble component content.

Yet another object of the invention is to provide such a mixture that has good structural stability within the environment of the human oral cavity.

Yet another object of the invention is to provide such a mixture, in which any need to use larger catalyst concentrations to achieve an effective rate and degree of curing is avoided.

Another object of the invention is to provide such mixtures having the above-described beneficial characteristics, despite the absence of filler and / or coupling component and the like.

Yet another object of the invention is to provide such mixtures in which, in a particularly effective embodiment, the stability of the monomer in the presence of a peroxy catalyst is effectively improved.

Yet another object of the invention is to provide a method for using such blends, wherein a high quality polymerization product is prepared.

Other objects and advantages of the invention will become apparent from the following description.

The said and related objects are achieved according to the invention, which in the broader form is a polymer honorable mixture for dental use and provides a method for its use, wherein the mixture has an accelerated cure speed and a high degree of cure and consists of at least one methacrylate monomer having 2 to b polymerizable double bonds, further, based on the monaner, about 0 to about 100% of an inorganic filler consisting of very small individual particles, again based on said monomer, about 0 up to 3% of a silane coupling agent, an effective catalyst-activating amount of an accelerator containing cupric ions, and again based on the monaner, about 0.5 to 3% of (a) a free radical releasing polymerization catalyst consisting of an organic peroxy compound, (b) a reducing agent for said peroxy compound and (c) m angels of (a) and (b), and wherein the concentration (b) is no greater than about b-0% of the total amount of (a) and (b).

Cupri ions are very easily supplied in the form of copper salts with organic and inorganic acids. Particularly preferred materials to be used herein include eupri acetate, cupric acetylacetonate, cupric chloride and cupric sulfate. The compounds can be used alone or as a mixture of two or more representatives. In addition, cuprous ions may also be present with the aforementioned compounds, although it has been found that the cupric compounds are generally more effective in obtaining both a high degree of transparency and a high curing speed. It is therefore particularly preferred that at least about 30% of the total copper ions used consist of cupric ions, Cu. However, as will be shown below, the use of cuprous salts alone provides a significant improvement over tests where copper ions are completely omitted. Whether this is due to the presence of cupric ions, which are always present in the available cuprous salts, or of the cuprous ions, or the combination of both, has not yet been clearly established.

8102128. * · * -H-

The amount of copper ions present in the monomer mixture is extremely small and is generally about 5 to 100 ppm, preferably 8 to 50 ppm, based on total monomer. In other words, the amount of copper ions is at least as many as is necessary to produce effective catalyst activating or accelerating effects. The term "total monomer" here means the total amount of monomer that would be present when polymerization actually occurs. Thus, according to a preferred embodiment, peroxy catalyst, monomer and filler, if used, are present in a first paste mixture, which is referred to as "oxidant" paste, while the reducing agent for said peroxy catalyst is incorporated in a second one. "reductant" paste included with. preferably contains the same components as the first paste, except for the peroxy catalyst. The pastes are mixed shortly before the dental application, after which polymerization is initiated. The copper ions can be added to one of the two pasta mixtures or to both pasta mixtures, the presence in the oxidant mixture being preferred. In any case, the concentration of copper ions in this embodiment is based on the total amount of monomer present in both the oxidant paste and the reductant paste. Based on the catalyst, the copper ion concentration is about 0.02 to 0.8% of the peroxy compound.

In general, addition of the copper compound to the liquid monomer systhesis (in which filler is absent) and intended as the oxidant paste is preferred.

The copper compound can be added to the mixture by adding it to the monomer component (s), which is usually liquid. The required dispersion can be accomplished by adding the copper compound to the monomer as a solution in the solvent, preferably a low boiling point polar organic solvent, such as ether or a low alcohol, for example, methanol. Since the solvent merely acts as a support for the copper compound, it is highly desirable that it be highly volatile so that generally most of the solvent, if not the entire solvent, in subsequent handling operations, for example, mixing, etc., is removed.

The amount of solvent used is very low, for example 81 02 128 -5-.

> i • ^ 1 ».

8θdpi Cu is supplied while using only a 1 # 's solution in methanol, the volume of the solvent being only 12.5 # of the monomer volume and 2.5 # of a suitable paste on a weight basis. If a filler is used, the copper compound can also be sorbed on that component, for example silicon dioxide, to be mixed with the monomer component or monomer components.

In addition to the copper compound, the composition of the preferred mixtures is as follows: 10 parts by weight

Monomer or monomers 100

Inorganic filler consisting of very small individual particles 0-400 15 Silane coupling agent 0.5-5.0

Peroxy catalyst 0.5-5> 0

Reducer 0.3-2.0

The methacrylate monomer is selected from materials having at least two and preferably two to four polymerizable double bonds per molecule, so that the cured mixture is cross-linked and is therefore more suitable for use in the oral cavity.

The most preferred monomers are those containing two polymerizable double bonds per molecule.

Desired features for such monomers include low polymerization shrinkage, low exotherm during polymerization, low water sorption, and ability to cure rapidly and completely in the mouth.

It is also desirable that the monomers have low volatility and are not irritating to the gums.

Methacrylate monaers which are particularly useful in accordance with the invention are those corresponding to the general formulas 1, 2, 3, 5, and 6, wherein M represents methacryloyloxy, i.e., CH 2 = C 1 CH 2 JCOG-; M represents methacryloyloxy or hydroxyl; A an alkylene group with 1-3 carbon atoms, such as methylene, propylene, isopropylene, a hydroxyalkylene group with 1-3 carbon atoms, such as hydroxymethylene, 2-hydroxypropylene, or an acetoxyalkyl group with 3-5 carbon atoms in the alkylene group, such as 2-acetoxypropylene, 3-acetoxyamylene, etc.; 8102 128 -6- equals 1-4, preferably 1 or 2; m equals 2 or 3 and p equals 1 .or 2, provided that the sum of m and p equals 4; R represents: hydrogen, methyl, ethyl, or -A-M, wherein A and M have the aforementioned meanings; Ar represents phenylene, for example o-phenylene, m-phenylene or p-phenylene. or alkyl-substituted phenylene, for example, tolylene or 5-t-butyl-m-phenylene or a cycloaliphatic group having 6 to 10 carbon atoms, such as 1,3-cyclohexylene; B a group \ / ¾.

Where C 1 and R 4 independently represent one another: hydrogen, alkyl, for example, C 1 to C 1 alkyl, or substituted alkyl; and R 'represents an alkylene group with 2-12 carbon atoms, such as ethylene, dodecylene, etc., or the group -R (OR 40R. -, in which R is an alkylene group with 2 to 3 carbon atoms, such as ethylene, propylene .... 3 or isopropylene; and x equals zero to 5; and R represents phenylene, tolylene, methylene-bis-phenylene or an alkylene group having 2-12 carbon atoms.

Monomers of the above formulas are well known and are commercially available. Also, they can be easily obtained by conventional synthetic routes, for example, by reacting a phenolic compound such as diphenolic acid, phloroglucinol or bis-phenol-A in the presence of various tertiary amines with glycidyl methacrylate or by reacting methacrylic acid with an epoxide containing compound, such as the diglycidyl ether of a bisphenol. Some of these monomers can also be prepared by reacting suitable alcohols with methacrylic acid, methacrylyl chloride or methacrylic anhydride.

Examples of monomers corresponding to these formulas include: a compound of the formula 7; a compound of the formula 8; C-E CH 2 OCO (CH 3) = CH 5]; CH3CH2CI CH2 -O-C (= O) -C (CH3) = CI2] 3; CH2 = C (O¾) COO (CH2) ^ OCOC (CH3) = CH2; CH2 = C (C123) C00CH2CH20CH2CH20CH2C120C0C (CH2) = CH2; a compound of the formula 9; 8102128 τ ί -; a compound of the formula 10; a compound of the formula 11; a compound of the formula 12; a compound of the formula 13.

Monitoring with formulas 1, 2, 3 and 4 is preferred in practice according to the invention. Of these monomers, the compounds of formulas 1, 2 and 3 are particularly preferred, while monomers of formula 4 are more often used in mixtures with one or more of the monomers of formulas 1, 2 and 3.

Other suitable methacrylate monomers which can be used in the practice of the invention include those corresponding to the following formulas, wherein M and Ar have the meanings mentioned above: (MR ^ OAr) C (CH, L, wherein R 1 represents isopropylene;

C ^ * d ^ C

(MR'OAr) and (MR'O) Ar, wherein R '2 represents 2-hydroxypropylene; o 6 MAS M, wherein R is hydroxycyclopentyl or hydroxycyclchexyl and A represents 2-hydroxyethylene; and 8 8 M2R, wherein R 0 represents a group of the formula 14, 15, 16 or IJ.

Preparative details for many of these samples are given in U.S. Pat. Nos. 3,066,112; 3-721,644; 3,730,749; 3,770,311 and 3,774,305. A tertiary eutectic monomer mixture, which can also be used in this invention, is described in U.S. Patent 3,539,526. All these references relate to the patents in their entirety.

It is to be remembered that mixtures of two or more suitable methacrylate monomers are also within the scope of the invention.

In fact, depending on the choice of samples, mixtures are often highly desirable to optimize the characteristics of the resulting dental mixture. For example, it is preferred that the monomer or monomer mixture has a viscosity of about 10 "1 Pa.s to about 10 Pa.s determined at room temperature using a Brookfield viscometer at 20 rpm.

The inorganic particulate filler, which is used in the mixtures according to the invention, comprises aerated silicon dioxide, quartz, crystalline silicon dioxide, 8102128 -8-amorphous silicon dioxide, sodium glass granules, glass rods, ceramic oxides individual particles "existing silicate glass, radiopaque glasses (" barium and strontium glass) and synthetic minerals, such as beta-eucryptite (LiAlSiO4), the latter of which has a negative thermal expansion coefficient. It is also possible to use finely divided materials and powdered hydroxylappatite, although materials which react with silane coupling agents are preferred. As fillers, there are also available polymer-coated colloidal silicon dioxide or silicon dioxide with a particle size of less than 1 micron. Small amounts of pigments can also be included to match the mixture to the various shades of the teeth. Suitable pigments are. iron oxide black, cadmium yellows and cadmium oranges, fluorescent zinc oxides, titanium dioxide, etc., among others. The filler particles should generally have a diameter of less than about 50 µm and preferably less than 30 µm. It should be noted that the filler is an optional ingredient and that blends which do not contain a filler are used when the dental mixture is for use as a coating, space sealant, or amalgam repair gap, or adhesive .

The silane coupling agents or adjusting agents ("keying agents") are substances which contain at least one polymerizable double bond which can react with the methacrylate monomers. Examples of suitable coupling agents are vinyl trichlorosilane, tris (acetoxy) -25 vinyl silane, 1-N- (vinyl benzyl aminoethyl) aminopropyl trimethoxysilane-3 and 3-methacryloxypropyl trimethoxysilane. The latter material is preferred to be used with methacrylate monomers because the reactivity of the double bonds is the same.

Peroxy catalysts which are suitable for the invention and which can initiate the polymerization of the methacrylate monomer or methacrylate monomers are well known for this purpose and include, inter alia: conventional peroxy and hydroperoxy compounds such as cumene hydroperoxide, p-menthan hydroperoxide , diisopropylbenzene hydroperoxide and t-butyl hydroperoxide. Hydroperoxides are preferably used among the organic peroxy-polymerization catalysts, while cumene hydroperoxide (CHP) is particularly preferred. If desired, peroxide stabilizers such as ascorbic acid, 8102128-9 maleic acid and the like may also be included in small amounts.

The reductants suitable for the invention generally include all materials which are capable of reacting with the peroxy compounds, the polymer being known to form 5 initiating free radical suppliers. Particularly suitable for the invention is a substituted thiourea of formula 18, wherein X represents H or Y, wherein Y may have any of the following meanings: an alkyl group having 1 to 8 carbon atoms, such as methyl, butyl, octyl; a cycloalkyl group with 5 or 6 carbon-10 atoms, such as cyclopentyl, cyclohexyl; an alkyl group of 1 to 8 carbon atoms, such as chloroethyl, mercaptoethyl, hydroxymethyl and chloroethyl, substituted by chlorine, hydroxyl or mercapto; an alkenyl group with 3 to 1 carbon atoms, such as allyl or methallyl; an aryl group with 6 to 8 carbon atoms, such as phenyl or xylyl and a phenyl group substituted by chlorine, hydroxyl, methoxy or sulfonyl, such as chlorophenyl, phenylsulfonyl, hydroxyphenyl and methoxyphenyl, an acyl group with 2 to 8 carbon atoms, such as acetyl, butyryl, octanoyl; an acyl group substituted by chlorine or methoxy, such as chloroacetyl, chlorobenzoyl, chlorotoluoyl and methoxybenzoyl; an aralkyl group with 20 to 8 carbon atoms, such as benzyl, or an aralkyl group substituted by chlorine or methyl, such as methoxybenzyl; while Z represents 3Ξ, 3ΞΧ or IlXg. Examples of compounds of this type which are suitable for use in practice are: methylthiourea, isopropylthiourea, butylthiourea, octylthiourea, benzylthiourea, acetylthiourea, benzoylthiourea, octanoylthiourea, cyclohexylthiourea, allylthiourea trimethylthiourea, 2,2'-xylylthiourea, p-tolylsulfonyl-thiourea, 1-octyl-3-phenylthiourea, o-methoxyphenylthiourea, m-hydroxy-phenylthiourea, 1,1-diallylthourea, 1,3-diallylthiourea -methoxybenzylthiourea, 1- (hydroxymethyl) -3-methylthio-30 urea, 1,1-dibutylthiourea, 1,3-dibutylthiourea, 1- (p-chlorophenyl) -3-methyltiourea, 1-butyl-3-butyrylthiourea acetyl-3-phenylthiourea, 1-methyl-3- (p-vinylphenyl) thiourea, 1-methyl-3-ol olthourea, 1-methyl-3-pentylthiourea, 3Hethyl-1,1-diphenylthiourea and 1-acetyl- 3- (2-mercaptoethyl) thiourea. While any of the aforementioned thio-urea derivatives may be used in the practice of the invention, preference is given to the mono-substituted thiourea derivatives, ie those having the aforementioned formula, wherein X equals 8102 12 8 -TO- equals H and Z equals HH. Phenylthiourea, acetylthiourenm and allylthiourea are particularly preferred. The mixture preferably contains about 0.5 to about 1% by weight of the reducing agent.

The invention is further elucidated by means of the following examples.

Examples I-X1Y

Radiopaque reductant pastes with the following compositions were prepared:

Composition 'in wt. $ 10 Ingredient A B £ £ -JL5 HUPOL ^ 10.27 10.2¾. 10.27 10.27 10.27 10.27 10.27 10.27 IMDMA ^ 10.27 10.2¾ 10.27 10.27 10.27 10.27 10.27 10.27 A-1T4 1.03 1, 02 1, 03 .1.03 1, 03 '1, 03 1, 03 1.03

Acetylthiourea .0.43 0.43 0.43 0.43 0.43 0.43 0.43 0.43 15 Ascorbic acid - 0.07 - - - - -

Cu ++ ^ - - 0.00022 0.00044 0.0011 0.0022 0.0033 0.044

Imsil A-10 5) 41.8641.86 41.86 41.86 41.86 41.86 41.86 41.86

Corning 7724 ^ 36.14 36.14 36.14 36.14 36.14 36.1¾. 36.14 36.14

Total 100 100 100 100 100 100 100 100 20 ^ BIS (GMA) 2) 1,6-hexanediol dimethacrylate 3).

2-methacryloxy-propyl-trunethoxyslane In the form of a methanolic solution of cupric acetate added to the monamer mixture.

25 Amorphous Silicon Dioxide (Illinois Minerals) 6) Barium Glass (Coming).

Furthermore, radiopaque oxidant pastes with the following compositions were prepared: 8102128 -11-

Composition in percent%

Τηρ Reducer Mixture I Mixture J

OlTupol 9.94 9 78 78 HMDMA 9.9 9 9.78 5 A-m 0.99 0.98

Maleic acid - 0.41

As corbic acid 0.07 -

Cumene hydroperoxide ($ 80) 1.05 · 1 »05

Imsil A-10 JU, 93 41.79 10 Corning 7724 36.06 36.22

Total 100 100

The oxidant and reductate pastes were successively mixed with 1: 1 by weight in the manner indicated in the following table. The curing times are given in minutes and also include the time required for mixing: about 30 seconds.

The time at which the curing reaction ceased was determined by the fact that the material could no longer be cut or dented with a spatula. This moment could also be determined by measuring the percentage of polymerization product, which was insoluble in methanol after completion of the curing reaction. Samples of the polymer-forming mass were taken during the curing reaction at timed intervals; the cessation of this reaction was indicated by the moment after which the percentage of insolubles remained almost constant. The results are summarized as follows: 81 02 128 -12-

Example Oxidant Reductant dpa Cu Curing Temp.

Ho. pasta pasta in reductant time, min ° C

_ _ _ pasta _ _ IJC 2.2 3.5 - ^. 3 21 5 II "DM 2.8-3.2 23 III" E. 11.0 1.8-2.2 23 IV "F 22.0 1.7-2.2 20.5 V "G 33.0 1.5-1.8 21.5 VI" H kk, 0 1.3-1.8 23.10 VII ”. A none 0-5.0 27 VIII "C 2.2 3.3-3.8 21 IX" D 2.73.5 22.5 X "E. 11.0 1.8-2.2 23 XI" F 22 , 0 1.7-2.0 20.5 15X11 "G 33.0 1.3-1.7 21 XIII" Η Ιώ, Ο 1.25-1.6 23 XIV "A none 3.3- ^, 0 21

In each of the tests, curing was carried out in air, i.e. in an open vessel. Increased Cu concentration yielded faster cures.

Compared to Examples VII and XIV, where the copper accelerator is omitted, the numbers for the present invention indicate a marked improvement in the cure speed.

Similar combinations (1: 1) of reductant paste B with mixture I and mixture J gave similar results.

Examples XV-XVII

The procedure followed in the previous examples was repeated, except that a monomer mixture of Nupol: HMDMA in the weight ratio of 71:29 was used in each of the oxidant and reductant mixtures.

The filler was completely omitted in each of the examples.

Copper ions were supplied by the following compounds:

Example Ho. Accelerator: - XV cupric acetate XVI cupric chloride 35 XVII cupric acetonyl acetonate (no solvent) 810 2 12 8 Z. i -

When the results were compared with identical control tests, omitting the copper compound, an improved cure speed was achieved in each case.

Examples XVEII-XX.

The procedure mentioned in Examples XV-XVTI was repeated, but with the difference that the following substances were used as accelerators:

Example No. Accelerator (weight ratios) XVIII cupric acid / cuprous chloride (50:50) 10 XIX Cupric acetate / cuprous chloride (50:50) XX cupric chloride / cuprous chloride (50:50)

The results were similar to those of the previous examples.

Examples XXI-XXXIV

Each of Examples I-XIV was repeated with the difference that the cupric acetate was sorbed on the trap and then added to the monomer mixture. A similar improvement in cure speed was obtained in comparison to control tests where the copper compound was omitted.

20 Examples XXXV-XXXVCI

The following reductant-containing and oxidant-containing mixtures were prepared:

Reductant

Composition in wt / S

25 Ingredient Mixture K Mixture L Mixture M

NUPQL 9.9 9.9 9.9 HMDMA. 9.9 9.9 9.9

Acetylthiourea 0.1 + 5 0.1 + 5 0.1 + 5

Cu ** 0.0002 0.0005 0.0010 30 Corning TT2l + a) 36.25 36.25 36.25 IMS ID A-10a) 1 + 2.25 1 + 2.25 1 + 2.25

Silicon colloxal 1.30 1.30 1.30 a) x-oxylated 8102128 • A '

<"-1W

Oxidant mixture - IT

Ingredient Composition in wt% ICOL 9.325 HMIMA. 9.325 CHP (QO%) 1.05

Corning 772 ^ 36.25 IMSIL A-1.0a ^ ^ 2.25

Colloidal Silicon Dioxide 1.80 a. Silanized 10 On a clean glass plate, the oxidant paste was mixed with each of the three reduetant pastes in a 1: 1 ratio. The cure times were determined for each of the three blends by the time required for the blended material to resist incision or indentation by a plastic spatula. The results are summarized as follows:

Example Oxidant Paste Reductant-dpa Cu in Curing at 23 ° C

Ho. pasta reductant- in minutes ____________ _______________ ___ pasta_ _ XXXV H K 2 1 *, 2-5.0 20 XXXVI E N 5 2.5-3.0 XXXVII Η M 10 2.3-2.8

In each of the above tests, curing was performed in air (performing under glass or in a matrix strip covered cavity would result in shorter curing times). It is clear that increasing the concentration of Cu results in a shorter curing time.

Similar results were obtained when the foregoing examples were repeated, except that the following peroxy catalysts and reductant compounds were used, taking into account the previously defined ranges of quantities: as peroxygen catalysts: p-menthan hydroperoxide, diisopropylbenzene hydroperoxide and t-butyl hydroperoxide ; as a reductant and: allylthiourea, phenylthiourea and 3-allyl-1,1-diethylthiourea.

8102128

Claims (2)

1. A polymerizable dental mixture with an accelerated cure rate, consisting of at least one methacrylate monomer with 2 to h polymerizable double bonds, about 0 to about 100% 3, based on the said monomer, of an inorganic from highly small individual particulate filler, about 0 to 5% a based on said monomer, of a silane coupling agent, an effective catalyst activating amount of an accelerator containing cupric ion and about 0.5 to 5.0% based on said monomer, of (a) a free radical-releasing polymeric peroxy compound polymerization catalyst, (b) a reducing agent for said peroxy compound, and (c) mixtures of (a) and (b ), and wherein the concentration of (b) is no greater than about kQfe of the total amount of (a) and (b). A mixture according to claim 1, wherein the ratio of 15 (a) to (b) is about 2: 1. A mixture according to claim 1 or 2, wherein the reducing agent consists of a substituted thiourea compound. k. Mixture according to claim 3, wherein the reducing agent is a thiourea substituted by allyl or acetyl. Mixture according to claim h9, wherein the peroxygen compound consists of eumene hydroperoxide and the reducing agent is acetylthiourea. Mixture according to claim, wherein the peroxygen compound consists of eumene hydroperoxide and the reducing agent consists of allylthiourea. Mixture according to any one of the preceding claims, wherein the cupric ions are present as cupric acetate, cupric acetylacetonate, cupric chloride or mixtures thereof. Mixture according to any one of the preceding claims, wherein the concentration of the cupri ions is about 5 to 100 ppm, based on the monomer. 9. Mixture according to any one of the preceding claims, wherein the cup cupric ions are dispersed in the monomer. 10. Mixture according to any one of the preceding claims, wherein at least about ko% of the monomer consists of the reaction product of glycidyl methacrylate and bisphenol-A. 8102128 4: 11. A mixture according to claim 10, wherein at most 60% of the monomer consists of 1,6-hexanediol dimethacrylate. 12. Mixture according to any one of the preceding claims, wherein the mixture contains at most 50% by weight, based on the weight of the cupric ions, of cuprous ions. Mixture according to any one of the preceding claims, wherein the mixture has a pasty consistency. b. Process for forming a polymerization product suitable for dental applications, characterized in that methacrylate monamer with 2-k polymerizable double bonds is contacted with a redox polymerization catalyst capable of initiating polymerization of the methacrylate monomer and containing an organic peroxygen compound and a reducing agent therefor, the contact being conducted in the presence of an amount of cupric ion effective for activating the catalyst. 810 2 12 8 z 2 [(M- A - 0) n - Ar] 2 -B (M - A - 0C0) 2Ar 3 4 5 - (M - A) m CR p MgR '(M - A - OCO - NH) gR 3 6 7 CHo-M. "| 0 ^ 0 (0 ^) 0000 ^ 0 ^ -000 - ^^ - ^ - 00001 ^ 01 ^ 0000 (0¾) ^ ¾ CH - M 'ca, - k ^ 8 0 ^ = 0 (0 ^) - 000 - ^^^ = 0¾ OH CH3 CH3 oh 9 CH2 = C (CH3) COOCH2Ci (OH) CH2-0- ^ j-0-CH2-CH (OH) CH2OCOC (CH3) = CH2 1 ° c (ch3) cooc (CH3) 2 O-COC (CH3) = 0¾ n CH2 ~ C (CH3) C00-CK2CH (0H) CHg-0 - ^^ - ^^ - 0CHgCH (0H) CH20C0C (CH'3) »CH2 0CH2CH (0H ) 0C0C (CH3) = CH2 12 i “3 .. CH-2 = C (CH3) COO-CH2CH2OCONH- ^ ^^ JTHCOOCH CH OCOC (CH) = CH 2. V 3 2 8102 128 Colgate-Palmolive Company 13 · CH CH = C (CH) C00-CH2CH-0C0NH-CH2CH2C-gC-CH-NHC00CH-CH2-0C0-C (CH3) = CH2 CH CH CH CH to - CH3 _ - / H WVhY w ch3 ^ / 15 -CH2 - / ^ \ - CH2- 16 17 -012η (Ο) -0 ^ Ο} - [Η2- -CH2 ^ CH2- YSX — H - C — Z 810 2 12 8 Colgate-Palmolive Company _