IE58156B1 - Intermediate substance for dental and related purposes, process for its production and the use thereof - Google Patents

Abstract

1. Claims for the Contracting States : BE CH DE FR GB IT LI LU NL SE Composition for the preparation of plastic or hard materials for dental technical, (dental) medical and related purposes, which includes a thermoplastic material and ordinary additives, characterised in that the said composition also contains 0.05 to 10 wt.% jojoba oil. 1. Claims for the Contracting State : AT Process for the production of a preparation for plastic or hard compositions for dental technical, (dental) medical and related purposes, which includes a thermoplastic material and ordinary additives, characterised in that the said composition also contains 0.05 to 10 wt.% jojoba oil.

Description

The invention concerns a substance for the preparation of plastic and/or hard substances for odontotechnical, medicodental and related purposes, a process for its production and the use thereof.

The use of acrylic or methacrylic acid esters for medicodental and odontotechnical purposes, especially when taking jaw impressions, as well as for the inner lining of plastics dentures etc., is known. It is also known that additives such as plastics of another type, cellulose derivatives, (natural) resins (eg copal, sandarac), paraffin, wax, oil, dyes and fillers may be added for this purpose to the acrylic or methacrylic acid esters. DE-OS 27 18 017 describes the addition of metal soap and/or metal silicate to such plastic or hard sustances for odontotechnical and medicodental purposes.

The acrylic or methacrylic acid esters are generally used in such a way that a powder, bead or splinter granulate of a polymer or mixed polymer of these compounds is dissolved in a liquid monomer and this solution is hardened optionally with addition of promoters. But when using such mixtures there are certain drawbacks.

While the dissolution of the powder in the liquid is relatively time-consuming, in the case of cold polymerization in the powder-liquid system, parts of the polymer remain undissolved, which causes a loss of stability and homogeneity of the material. It is desirable to create a substance which ensures easier processing, optionally on the basis of improved viscosity and plasticity of the material.

The cold polymers containing monomeric methyl methacrylate are also regarded as irritating to mucous membranes. In this respect too it is desirable to create an improved dental substance which would avoid or reduce this disadvantage. In addition burns can result in the mouth from the rapid polymerization of cold polymers. When producing linings from momomeric methyl methacrylate, the products do not always have perfectly smooth surfaces, and are therefore partially absorbent of the saliva, making them more easily attacked by the microflora in the mouth.

The invention is therefore based on the object of creating a substance of this type mentioned above which, owing to its improved viscosity, ensures easier and faster processing, has better mechanical strength and develops a healing effect at pressure points and inflammations in the oral region as well as in articulated dentures, forms smooth surfaces, is devoid of smell and taste as well as being compatible with the mucous membranes, while maintaining optimal fitting over lengthy periods of time. The substance should be easily adjustable if necessary to the required consistency, eg hard or elastic or remaining soft, respectively.

The object above is solved inventively by the provision of a substance of the type mentioned above, which is characterized in that it comprises, apart from the thermoplastic and conventional additives, from 0.05 to 10% by weight of jojoba oil.

This oil as used in the invention is the oil of the jojoba plant, which belongs to the buxaceae family, after extraction and purification. Hereifafter the term jojoba oil, as used in the invention, also covers jojoba wax.

It is preferable to use the jojoba oil together with the other components for the manufacture of plastic or hard substances according to the invention in a concentration of 0.1 to 5% by weight.

By adding jojoba oil to the substance for the production of plastic or hard substances as in the invention, it is possible to improve the workability, toughness, hardness and strength as well as the surface properties and the durability in the mouth (no aging manifestations, such as brittleness, odor formation, and unattractive color formation) while the inventive substance develops a healing effect at the pressure points and inflammations in the oral region as well as with articulated dentures, and to obtain non-porous, non-brittle and non-shrinking substances which are also especially compatible with the mucous membranes and which are suitable for the most varied medicodental and odontotechnical and other purposes to an outstanding degree. Using the inventive substances it is in particular possible to attain elastic, hard or permanently soft molding materials or inner linings as desired, in which the hardness or the elasticity can be regulated fully as required. In particular the inventive substance is characterized by the fact that an optionally plastic or hard odontotechnical or medicodental substance can be produced which maintains its optimal fitting and viscosity or plasticity in the mouth over long periods, develops a healing effect at the pressure points and inflammations in the oral area as well as with articulated dentures, and possesses a good mucous membrane compatibility.

As the solvent or dispersion agent for the homo-, co-, or mixed polymer share, the methyl ester of acrylic and/or of methacrylic acid can be used, while in the hot polymerization of acrylates the methyl ester additive can be omitted. This embodiment of the invention is especially relevant when hot polymerization is effected, or when polymerization in the mouth of the patient himself is omitted. An especially preferred composition according to the invention contains however no substantial proportion or (especially advantageous) no proportion at all of monomeric esters of acrylic acid or methacrylic acid, but instead of them high boiling point ester derivates of the named acids are used. Here special consideration is given to a content of at least one monomeric acrylic and/or methacrylic acid ester having from 6 to 10 carbon atoms. Examples are provided by 2,3-epoxypropyl-, n- or t-butyl, n- or cyclohexyl methacrylic acid ester or mixtures of these monomers. Equally good use can be made of the analogous esters of the acrylic acid, while it may be especially expedient to use mixtures of the named monomeric acrylic acid esters and methacrylic acid esters. Although the use of ester derivatives with a total of from 6 to 10 carbon atoms is preferred, at least partial use may be made of ester derivates of acrylic or methacrylic acid whose total carbon number is below the range shown as preferred above, from 6 to 10 carbon atoms, for example methacrylic acid dodecyl ester, methacrylic acid triethylene glycol monoethyl ester, methacrylic acid ethylhexyl ester etc. A specially advantageous monomer is, lastly, a reaction product of glycidyl methacrylate and bisphenol A.

The polymers may be basically polyacrylates and polymethacrylates or mixed and/or copolymers thereof. In addition certain proportions of plastics of another type may be present, such as polyvinyl chloride, polyvinyl acetate, or polyvinyl alcohol. Preferred is a mixture of polymethacrylates of average molecular weight. Among them especially favourable are those which have good solubility properties in the proportions of monomers used and in the solvent proportions partly contained therein. Such poly (methylmethacrylate) mixtures of average molecular weight, which for example are soluble in esters, ketones, chlorinated aliphatic hydrocarbons, cyclic ethers etc, and have thermoplastic properties, can be obtained commercially.

Preferably the thermoplastic resin is thus, before polymerization, a mixture of monomers and polymers or of mixed polymers of acrylic and methacrylic acid esters. This mixture is preferably present as a paste or as a solution.

The proportion of polymer in the monomeric solution, which optionally contains additives, can vary within wide limits. Proportions of polymers between about 10 and 70% by weight, based on the total composition, will normally be present. A specially preferred range of the proportion by weight of the polymer amounts to from 10 to 40% based on the total substance, since it very easily provides fluid-to-pasty and doughy compositions which can be cast, injected, distributed with the spatula or squeezed as fluid, doughy or pasty substances from pressure vessels and distributed.

To these solutions or syrups, the pastes or doughy compositions of polymers or mixed polymers in the monomer mixture there are added metal soaps and/or silicates, a catalyst and optionally an accelerator, for hardening.

Stearates, laurates, oxystearates, palmitates, montanates, oleates or ricinoleates of metals such as aluminium, magnesium or calcium have been found suitable as the metal soaps. Preferred are the alkaline earth soaps, which metal soaps should be present in finely divided form. Special preference is given to the use of magnesium stearate and calcium stearate. The added amounts of metal soap(s) and their mixtures add up advantageously to from 0.1 to 10% by weight, based on the total substance.

Among the silicates whose addition has been found favourable it is primarily alkali metal silicates which are considered, especially the commercially available, soluble waterglass compounds of which both sodium and potassium silicate or mixed alkali metal silicates can be used. Especially suitable is alkali metal aluminium silicate. The amount of such a silicate added is preferably 1.5% to 5% based on the total amount of the substance. In these waterglass preparations, the socalled oil number should not be more than 26, while an oil number of about 22 has performed especially well.

In the event that special stress will be applied to the plastic or hard substance for odontotechnical or medicodental and related uses, it may be expedient to provide a proportion of a cross-linking agent in the inventive composition. Among the known substances effective for the cross-linking of methacrylate or of acrylate, special suitability attaches to olefinic dimethacrylates such as ethylene dimethacrylate, propylene dimethacrylate and polyethylene glycol dimethacrylate. It is expedient that the optionally used polyethylene glycol dimethacrylate cross-linking agent should have a relatively low molecular weight.

The cross-linking agent which is especially suitable for prevention of the later emergence of stress cracks can for example be added in amounts of from 0.1 to 10% by weight, based on the total composition.

The cross-linking agent can however also be used in larger amounts and can partly replace the monomeric (meth)acrylate. According to one embodiment of the invention, which can be regarded as preferred for certain applications, the monomer proportion is totally replaced by a monomeric cross-linking agent. In the latter case, the polymer content would thus be exclusively dissolved in the monomeric cross-linking agent.

In one preferred embodiment the inventive substance for the manufacture of plastic or hard substances for odontotechnical and medicodental purposes consists of a two-component system, with special preference for a powder system and a liquid system, in which the powder system includes the polymer plastic and optionally the metal soap, filler and peroxide (catalyst), while the liquid system includes the monomeric acrylate, the softener and the accelerator as well as the jojoba oil.

Moreover to increase the shelf life of the compositions according to the invention, a small amount of stabilizers or inhibitors can be added thereto, which prevent unintended further polymerization of the solution when it is stored. For this purpose eg phenol compounds such as aminophenols, dibutylmethyl phenol, or butylhydroxyanisole or even hydroquinone, pyrogallol or pyrocatechol may be considered. These inhibitors can be added in amounts of from about 2 to 100 ppm of the substance.

Methacrylates usually have a typical bitter aftertaste, which temporarily, for example when fitting the (functional) impression tray charged with moulding material, or the lining of a denture, may be found disturbing.

To overcome this problem, there may usefully be added sweeteners free of carbohydrates, such as cyclamates, or of anti-cariogenic sugar substitutes on a carbohydrate base, for example xylite; a mixture of sodium cyclamate with 10% saccharin, well known in commerce, has been found specially useful. Moreover the solution can contain the usual added colorants.

The catalyst used to harden the plastics substance can be added, basically, in powder form. But it is used with advantage in the form of a solution in a solvent in which it is preferably easy to dissolve, since in this way it is distributed easily and evenly in the acrylate solution. In the manner known per se, for the catalysts or initiators one can use peroxides, such as hydrogen peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, as well as dialkyl and diaryl peroxides, ketone peroxides, diacyl peroxides such as dibenzoyl peroxide, or peroxy acids, as well as azo compounds, such as azo-di-isobutyric acid nitrile and azodicarbonamide, which are used optionally in solvents such as dibutyl phthalate, methanol, acetic ester, acetone or methyl ethyl ketone.

In the case of catalyst systems which are selfhardening, ie the hardening is to be effected without the additional use of heat, an accelerator or activator, which effects the decompositon of the initiator and thus the start of the polymerization of the monomer into polymer, should be included in the actual catalyst or initiator. For such acceleration, tertiary amines, alkylamines, alkylarylamines and oxyalkylamines have proved satisfactory, as well as reducing agents such as sulphinic acids or dithionites, which can be added in amounts of from 1 to 3 % by weight. But instead of the above listed catalyst systems, all the other systems usable for the polymerization of acrylates or methacrylates may of course be employed. For example as the accelerator, consideration may be given to para-toluidine in amounts of between 0.5 and 2% by weight. The accelerator is preferably contained in the syrup or paste or in the liquid itself, according to the invention.

But the hardening can be performed even in the absence of accelerators, for example by the influence of ultra-violet rays. In the case of hot polymerization the hardening is achieved without accelerator by supplying heat. i I The inventive compositions are preferably made in such a way that, directly before the use of the substance, in a two-component system which consists of a powder system comprising the polymer, optional fillers and' metal soaps, and catalyst, and a liquid system consisting of the monomeric acrylate, which optionally i comprises softener, accelerator and the inventive jojoba oil, the mixing is performed. i In the practical use of the inventive composition, for example for lining a prosthesis, the substance is applied on the previously roughened surface of the prosthesis which has expediently been solvated with a solvent, and is inserted in the mouth of the patient, where within a few minutes the substance fully polymerizes under pressure and optionally with the exclusion of air. When carrying out repairs to dental prostheses for example it is advantageous to cover the applied inventive composition with glass- or cellophane paper, since the hardening should take place expediently with exclusion of air.

Using the inventive substances in medicodental or odontotechnical work has the great advantage that now only the finished polyacrylate solution can be made to solidify in the minimal time by adding a catalyst solution, preferably in the form of a two-component system comprising a powder system and a liquid system, without any shrinkage or aging of the material taking place in the course of time, while the optimal fitting and moulding can be attained by the moulding or lining material. According to requirements, elastic, permanently soft or hard dental substances can be obtained, and the polymerization can take place entirely in the mouth of the patient, without burns, erosions or irritation of the mucous membranes occurring, even in the case of cold polymerization.

The inventive substances are primarily suitable for dental purposes, such as the individual production of an adapted function impression tray with the corresponding moulding for the manufacture of a dental prosthesis, as the moulding and lining material for the production of a tooth guard, especially for sportsmen, and generally as impression substances, for linings and repairs of dental prostheses. But they can also be used in other ways, for example as fingernail replacements or for otoplasty, the repair of hearing aids, as well as for the lining of leg and arm prostheses and the like, as skin replacements, for the production of soft and bone portions in medicine as well as for cosmetic corrections in medicine.

A special advantage in the use of the inventive compositions consists of the fact that owing to their easy manipulation, they can also be used in self-medication, eg for those who use partial or total prostheses, for cosmetic corrections in self-medication, such as for example correction of the laughing wrinkles for users of prostheses.

The following examples are to explain in more detail the inventive composition as well as the process for its production and its use, without limiting the scope of the invention.

Example 1 In a mixing vessel, 25 parts by weight of a copolymer consisting of 96 parts by weight methyl methacrylate and 4 parts by weight of ethyl acrylate are mixed into 75 parts by weight of acrylic acid cyclohexyl ester, to which 1% p-toluidine and 2% 1,4-butandiol dimethacrylate have been added. Instead of the cycloalkyl ester one can also use 65 parts by weight of a mixture of methacrylic acid tertiary-butyl ester and methacrylic acid methyl ester in a ratio of 1:1 or of 1:2. To the syrup thus obtained 2% of a normal commercial alkali metal aluminium silicate and 2.5% of magnesium stearate as well as 1% of jojoba oil are added.

When using, a solution of 5 parts by weight benzoyl peroxide in 25 parts by weight of dibutyl phthalate is added to this mixture dropwise. After a short time the substance begins to become viscous, so that it can now be applied to the prepared prosthesis and inserted in the patient's mouth. In a few minutes it hardens, forming a hard inner lining.

Example 2: parts of a copolymer, consisting of 96 parts by weight of methyl methacrylate and 4 parts by weight of ethyl acrylate, are dissolved in a mixture of 50 parts methacrylic acid tertiary-butyl ester, methacrylic acid methyl ester and methacrylic acid n-hexyl ester, which are mixed in a ratio of 1:1:1. To this quantity 3% of magnesium stearate and 1% of a commercial alkali metal aluminium silicate, 1% p-toluidine and 1% jojoba oil are added. As in example 1, to work up this mixture, a benzoyl peroxide solution is added dropwise and in a short time a viscous substance is obtained which is easy to spread on the prosthesis and quickly provides an elastic lining which has an excellent fit, is stable and shows almost no shrinkage.

Example 3: A dental guard for sportsmen was prepared as follows, wherein the starting point was a function impression tray such as is described in DE-OS 27 18 017. This impression tray of a thermoplastic material is adjusted to the individual dental and jaw situation by light pressure after immersion in hot water at 70°C in order to soften it.

A moulding/lining material consisting of 40% by weight polyacrylate, about 55% by weight methacrylic acid hexyl ester, 1% by weight calcium stearate and 1% by weight jojoba oil, with conventional hardeners and accelerators, was subsequently poured into the function impression tray, and the latter again adapted to the dental and jaw conditions in the mouth. The above-named moulding/lining material was produced from a two-component system which was mixed directly before use. After about 10 minutes the elastic moulding/lining material has polymerized and forms a soft buffer zone between the relatively hard material of the tray and the teeth. To the extent that the impression tray used is provided with recesses in the occlusal overlay area, a part of the moulding/lining material penetrates beyond that area through said recesses when pressed by the impression tray filled with the moulding/lining material, is polymerized there and forms a soft buffer zone between the lower and upper rows of teeth. Since the process can be carried out simply, such a dental guard as that described above can be produced by the sportsman himself.

In the same way the above material may also serve, as a moulding material which is poured into a prepared impression tray already adapted to the jaw situation of the patient, to obtain a more exact, non-shrinking impression which is true to the model. It is especially advantageous according to the invention that when using an impression tray of acrylate plastic with the moulding material also based on acrylate, the use of an adhesive is not required, as it is with the commercial moulding materials. Thereby in a simple way an improved function impression tray or situation impression for making a denture or partial denture can be made, while also producing better-fitting and better-placed prostheses.

Claims (26)

Claims :

1. Substance for the preparation of plastic and/or hard compositions for odontotechnical, medicodental and related purposes wherein the substance comprises, apart from a thermoplastic resin and conventional additives, from 0.05 to 10% by weight of jojoba oil.

2. Substance as claimed in claim 1, herein the concentration of jojoba oil amounts to from 0.1 to 5% by weight.

3. Substance as claimed in claim 1 or 2, wherein the thermoplastic resin consists before polymerization of a mixture of monomers and polymers and/or mixed polymers of acrylic and methacrylic esters.

4. Substance as claimed in claim 3, wherein the thermoplastic resin comprises monomeric and/or polymeric methyl methacrylate.

5. Substance as claimed in claim 3, wherein the thermoplastic resin comprises an acrylic or methacrylic ester with a total of 6 to 10 C-atoms or a mixture thereof.

6. Substance as claimed in claim 5, wherein the ester is a hexyl ester.

7. Substance as claimed in claim 3, wherein the acrylate plastic material comprises substantially no methyl methacrylate.

8. Substance as claimed in claim 3, wherein the thermoplastic resin, before polymerization, is a solution or a paste of polymer(s) or mixed polymers in monomeric acrylic and/or methacrylic acid ester.

9. Substance as claimed in claim 8, wherein the proportion by weight of the polymer amounts to from 10 to 40%, based on the total mass.

10. Substance as claimed in claim 1, wherein it comprises conventional hardeners and accelerators.

11. Substance as claimed in claim 10, wherein it comprises one component of a two-component accelerator or hardening system.

12. Substance as claimed in claim 1, wherein it comprises a proportion of metal soap and/or silicate.

13. Substance as claimed in claim 12, wherein the metal soap is present in a concentration of from 0.1 to 10% by weight.

14. Substance as claimed in claim 12, wherein the metal soap is calcium stearate and/or magnesium stearate.

15. Substance as claimed in claim 12, wherein the silicate is present in a concentration of from 1.5 to 5% by weight.

16. Substance as claimed in claim 15, wherein the silicate is an aljcali metal aluminium silicate.

17. Substance as claimed in claim 1, wherein it contains a cross-linking agent.

18. Substance as claimed in claim 17,. wherein the cross-linking agent is an olefinic dimethacrylate or a (poly)ethylene glycol dimethacrylate, which is added to the monomeric (meth)acrylate or constitutes exclusively the monomer component.

19. Substance as claimed in one or more of the preceding claims, wherein it consists of a powder system and a liquid system, where the powder system comprises the polymeric plastics material and optionally the metal soap, filler and catalyst, and the liquid system comprises the monomeric acrylate, the softener, and the accelerator as well as the jojoba oil.

20. Process for the production of the substance as claimed in one of claims 1 to 19, wherein a two-component system, consisting of a powder system which comprises the polymer, optionally the filler, metal soap and catalyst, and a liquid system consisting of the monomeric acrylate, which comprises optionally ~ the softener, accelerator and jojoba oil, is mixed.

21. Use of the substance as claimed in one of claims 1-19 for production of odontotechnical and medicodental moulds and inner lining materials.

22. Use of the substance as claimed in one of claims 1-19 for production of inner linings of artificial limbs.

23. Use of the substance as claimed in one of claims 1-19 as the mould material for the production of a tooth guard, especially for sportsmen and sportswomen, as well as in the preparation of an individually fitted (functional) impression tray.

24. Substance for the preparation of plastic and/or hard substances for odontotechnical, medicodental and related purposes, substantially as herein described.

25. Process as claimed in claim 20, substantially as herein described.

26. Substance use as claimed in any of claims 21-23, substantially as herein described.