CH625120A5 - Materials containing fluorine compounds for dental purposes - Google Patents

Description

The invention relates to materials for dental purposes based on monomeric, oligomeric and / or polymeric substances or substance mixtures in combination with fluorine compounds, which are characterized according to claim 1 or 6.

The rest Ri in the fluorosilanes represents an organophilic group which primarily determines the compatibility with the monomeric, oligomeric and / or polymeric substances and thus a homogeneous distribution of the fluorosilanes in the materials.

Possible materials for dental purposes in polymeric form are, for example, prosthesis, crown and bridge materials and materials for plastic teeth. The polymeric substances can be dissolved in solvents e.g. for sealing materials and dental lacquers. A monomeric or oligomeric polymerizable substance can also be used as the solvent for the polymeric substance, tooth enamels being obtained, for example, if the monomeric or oligomeric substance is in excess, e.g. paste-like filling materials or starting materials for teeth, crowns, bridges or dentures, if the polymer substance is present in a higher proportion. The monomeric and / or oligomeric substances can also be used as sealing materials and dental lacquers without the addition of a polymeric substance, optionally with the addition of a solvent.

Monomeric, oligomeric and / or polymeric dental materials are known per se.

The radical Rj in the fluorosilane preferably contains at least one of the groups

/ 0 \? H

■ CH - CH - or - C -

I.

H

substituted phenyl or benzyl radical, a styryl radical, a hydroxyalkyl radical having 3 to 8 carbon atoms esterified by acrylic or methacrylic acid or a cyclohexylalkyl radical, in which the alkyl radical contains 2 to 5 carbon atoms and the cyclohexyl radical by one or two hydroxyl groups and / or lower Alkoxy groups or substituted by an epoxy oxygen atom.

Particularly preferred dental materials are those in which Ri is the group in fluorosilane

625-20

4th

ch2 «a - c - o - ch.

- CH. £ - Cïï2

CH- 0?

or represents a / 3-cyclohexyl-ethyl radical, in which the cyclohexyl radical in positions 3 and 4 is substituted by two hydroxyl groups, a hydroxyl group and a lower alkoxy group or by an epoxy oxygen atom.

The fluorosilane content of the materials according to the invention is generally about 1 to 20, preferably about 2 to 10 wt .-%.

The fluorosilanes can be prepared by hydroxyl groups or alkoxy groups (in which the alkyl groups contain 1 to 3 carbon atoms) in a silane of the formula in which R 1 has the meaning given above and R 2 to R 1, which can be identical or different from one another. represent, at least one of the radicals R2 to R4 exchanged for fluorine by reaction with hydrofluoric acid.

The production of the fluorosilanes can e.g. by reacting methacryloxypropyltrimethoxysilane with hydrofluoric acid. The silane is expediently diluted with an alcohol and reacted with the hydrofluoric acid in a reaction vessel which is resistant to hydrofluoric acid and suitably consists of plastic. An exothermic reaction occurs here. After the reaction mixture has cooled, stirring is continued for a certain time. The solvent is then evaporated off and the residue is dried. When using the above-mentioned starting material, oxy-propyl methacrylic difluoro-hydroxysilane is obtained as a low-viscosity residue.

The fluorosilanes of the above formula are insoluble in water in contrast to the fluorine compounds commonly used to combat caries. In contrast, they dissolve easily in most organic solvents such as acetone, trichlorethylene, alcohol and monomeric methyl methacrylate.

Fluorine-containing plastics can e.g. B. can be obtained by converting a material according to the invention, containing fluorosilanes dissolved in monomeric methyl methacrylate, into a plastic mass using the known dough method with peroxide-containing methyl methacrylate, which in a gypsum mold according to the hot pressing technique is converted to a test specimen at elevated temperatures, e.g. do about 100 ° C, polymerized.

A test specimen obtained in this way shows good flexural, tensile and compressive strength even after storage in water for several months. In comparison, test specimens with additions of water-soluble sodium fluorides show far worse results in the strength test after storage in water; the test specimens also show a strong white color.

In addition to their good mechanical strength properties, the test specimens obtained with the materials according to the invention also show good results in the release of fluorine. The hydrogen fluoride that slowly emerges from them through hydrolysis diffuses very easily through the water-impermeable plastic and can thus continuously release the fluoride ions required for consolidation to the tooth enamel. The fluorosilanes of the above formula are therefore very suitable as additives for denture materials, crown and bridge materials and 10 materials for acrylic teeth.

In a similar way, fluorine-containing dental lacquers consisting of a liquid component A and a solid component B can be produced. A lacquer for fissure sealing usually consists of 80 to 40% of a liquid 15 phase, which e.g. from monomeric methyl methacrylate, the di-functional esters of acrylic or methacrylic acid with ethylene glycol and an initiator, e.g. Dimethyl-p-toluidine, while the solid phase contains 20 to 60% polymethyl methacrylate and a cold polymerization catalyst, e.g. Benzoyl peroxide. If the known organic or inorganic water-soluble fluorine compounds, such as sodium fluoride etc., are replaced by the water-insoluble fluorosilanes of the above formula, e.g. by oxypro-pyl methacrylic difluoro hydroxysilane, an inventive material for sealing fissures is obtained, which adheres firmly to the teeth, is insensitive to signs of dissolution by the saliva of the oral cavity, meets the requirements for good abrasion resistance and also meets the requirements for the caries control shows the desired effect of evenly releasing fluorine ions to the tooth enamel over a long period of time. This steady release of fluorine over a longer period of time prevents de-mineralization and enables remineralization of the tooth enamel, which makes the fluorosilanes of the above formula very suitable as a prophylactic treatment for caries.

The materials according to the invention containing fluorosilanes are suitable for filling materials. Today, these are mostly manufactured as a two-component system. A base paste of 15 to 20% of an organic binder, e.g. the long-chain oligomer based on bisphenol-A and glycidyl methacrylate (hereinafter referred to as bis-GMA) known from U.S. Patent 3,060,112, 10 to 5% of a conventional difunctional crosslinker, e.g. Triethylene glycol di-methacrylate, 5 to 2% free methacrylic acid to achieve a higher reaction rate, 10 to 3% of a fluorosilane and 60 to 70% finely divided silicon dioxide. Paste component A contains a peroxide catalyst, e.g. Benzoyl peroxide, and paste component B as an initiator, a tertiary amine, e.g. Dimethyl-p-toluidine. An excellent filling material is thus obtained which retains its good mechanical properties through the addition of the fluorosilane and continuously releases fluoride ions in a suitable number to its surroundings. The cariostatic effect is achieved which has been shown to significantly reduce the formation of caries.

The invention is illustrated by the examples below.

example 1

100 g of commercially available methacryloxypropyltrimethoxysilane are diluted 1: 1 with isopropanol in a polypropylene vessel, and 50 g of 40% hydrofluoric acid are slowly introduced into this solution. The reaction is exothermic. After the mixture has cooled, it is evaporated in a rotary evaporator (Rotavapor) at 60 ° C. The resulting low-viscosity, polymerizable fluorosilane compound oxypropyl methacrylic difluorohydroxysilane has the following formula:

25th

30th

35

40

45

50

55

60

5

625 120

CH, 0

i * t

CH «- C - C • £ 0

This substance is water-insoluble, but soluble in organic solvents and also easy to polymerize.

10 g of the fluorosilane compound obtained above are added to a mixture of 35 g of monomeric methyl methacrylate and 65 g of peroxide-containing polymethyl methacrylate. The mixture according to the invention is polymerized by the dough method in a cuvette using the hot press technique for prosthesis materials at 100 ° C. In the same way, a monomer-polymer mixture is polymerized, to which 5% 15 finely powdered sodium fluoride has previously been added. Furthermore, a mixture is polymerized without addition.

The plastics obtained are sawn into test specimens, on which the usual mechanical strength tests are carried out before and after water storage. The test specimens, which contain sodium fluoride, are white-opaque, while those with fluorosilane show the same appearance and the same transparency as the polymer without addition.

The test specimens are compared in the following table: 25

Weight

By

By increasing bend with bend at after

35/50 N

35/50 N

7 days after in water

7 days

4 weeks

in water in water

1.5% 2.3 / 4.2 2.0 / 4.1 35

0.9% 2.1 / 3.4 2.0 / 3.3

2.0% 2.0 / 2.0 2.0 / 3.0

40

With weight gain after 7 days of water storage, the plastic differs only slightly from that with fluorosilane. The plastic with sodium fluoride shows such low values because a large part of the water-soluble NaF salt has already been dissolved out of the polymer; 45 a direct comparison is therefore not possible.

Bending test tests are carried out according to DIN draft 13 907 from July 1973. A 50 mm long, 10 mm wide and 2.5 mm thick test specimen is produced from plastic without additives, plastic with NaF and plastic with the fluorosilane used according to the invention. The test specimens are loaded with 35N or 50N after 7 days and after 4 weeks of water storage and the deflection is measured in mm. The plastic with fluorosilane shows better values, especially with a load of 50N, i.e. the 55 high flexural strength desired for prosthesis materials is not impaired by the addition of fluorosilane.

Furthermore, after 12 hours of storage in boiling water, the polymer with NaF shows a rough and pitted surface, while the polymer with fluorosilane remains smooth. 60

To test for the release of fluorine ions, a small block of methyl methacrylate is polymerized, in which a natural tooth is embedded. The block is carefully sanded until the enamel of the natural tooth is on the surface. The enamel is polished with a rubber polisher. One half of the enamel is isolated with a suitable varnish. Press on the surface of the plastic block and thus also on the enamel

P

/

■ CH «- GH« - 31 - OH 2 2 x

\ F

a piece of polymer containing fluorosilane and stored in water at 27 ° C. for 24 hours. After the water has been stored, the cover containing fluorosilane is removed and the half of the tooth insulated with lacquer is cleaned. The surface of the enamel is etched for 30 seconds with 5% citric acid. The etched tooth surfaces are assessed under the microscope. The non-fluoridated half of the enamel is heavily etched (it appears black in the bright field of the microscope), while the half fluoridated with fluorosilane remains shiny and completely smooth.

Example 2

The material according to the invention for a fissure sealing lacquer consists of a component A and a component B, component A being a polymethyl methacrylate enriched with 1% benzoyl peroxide. Component B consists of 34% bis-GMA, 2% free methacrylic acid, 60% triethylene glycol dimethacrylate as a diluent, 0.8% dimethyl-p-toluidine as an initiator and 3.2% oxypropylmethacrylatedifluorohydroxy-silane.

If you mix 20% of component A with 80% of component B, you get a thin solution that can be applied with a brush to the carefully cleaned and dried teeth. The compound hardens quickly and forms a varnish-like protective film with high transparency and abrasion resistance, which strengthens the enamel while continuously releasing fluorine ions and thus confirms its caries-prophylactic properties.

Example 3

A suitable material for a filling material consists of 18% bis-GMA, 7% triethylene glycol dimethacrylate, 2% free methacrylic acid, 3% oxypropyl methacrylic difluorohydroxysilane and 70% finely divided silicon dioxide in the form of a paste.

If you divide the paste into two equal halves A and B and add 1% benzoyl peroxide to paste A and 1.5% dimethyl-p-toluidine to paste B, mix equal parts of component A and component B to obtain a tooth restoration material , which has satisfactory characteristics with regard to its physical properties, but is due to its caries-preventing effect due to the constant release of fluorine over a longer period of time than the level of the commercially available filling materials.

Example 4

25 gß- (3,4-Epoxycyclohexyl) -ethyltrimethoxysiIan and 50 g isopropyl alcohol are slowly mixed in a polypropylene vessel with a mechanical stirrer with 6 g about 70% hydrofluoric acid. The inflow of hydrofluoric acid is kept so low that the temperature does not rise above 40 ° C. After the hydrofluoric acid has been added, stirring is continued for another hour and the solution is evaporated on a water bath. The fluorosilane compound thus obtained theoretically contains 39.2% fluorine. The theoretical value is checked using the method as described in “Analyst, Dec. 1968, Vol. 93, pages 827-831”. The value found using this method gives 38.5% fluorine.

4.8 g of the low-viscosity fluorosilane compound thus obtained and 96 g of a commercially available tooth enamel (Plusprotector) are mixed and the mixture is used as a fluorine-containing tooth enamel. The paint was tested in vivo in a clinical test

CH,

Plastic without additives Plastic with NaF plastic with fluorosilane

625 120

6

applied to molars that had to be extracted to regulate tooth position. A tooth was extracted for control before the varnish was applied. After 11 or 14 days, the teeth treated with fluorine varnish were also removed and compared with the control tooth without fluorine treatment. The results, which show the clear fluorinating effect of the lacquer, are summarized in the following table:

5

Tooth patient fluorine varnish Fluorine concentration in ppm in the enamel at different depths in the mouth 5 / t 10 «15,« 27 ß 30 «40 / <60«

painted

A

14 days

1650

-

520

150

-

100

-

Control tooth

850

300

100

-

100

-

painted

B

! 1 day

1620

5 (10

320

-

300

-

100

Control tooth

-

450

250

160

-

200

-

100

s

Claims (9)

625 120 2nd PATENT CLAIMS 1. Materials for dental purposes based on monomeric, oligomeric and / or polymeric substances or mixtures of substances in combination with fluorine compounds, characterized in that as fluorine compound they contain at least one water-insoluble fluorosilane of the formula 10th contain in which Rj is an aliphatic, alicyclic, aromatic or heterocyclic radical having 5 to 12 carbon atoms, the latter being bonded to the Si atom via a carbon atom, and R2 and R3, which may be the same or different from one another, Fluorine, represent a hydroxyl group or alkoxy groups in which the alkyl groups contain 1 to 3 carbon atoms or a radical as defined under Rj. 2. Materials according to claim 1, characterized in that the rest Rt in the fluorosilane at least one of the groups CH = C -I X or / ° \ CH - CH - or - OH i C -I H wherein X represents hydrogen or a methyl group. 3. Materials according to claim 1 or 2, characterized in that R! in the fluorosilane a phenyl radical optionally substituted by lower alkyl groups or a vinyl group on the nucleus or by acrylic or methacrylic acid esterified hydroxyalkyl radical having 3 to 8 carbon-2o atoms. 4. Materials according to claim 1, characterized in that Rj in the fluorosilane the group CH2 - Ç - c - 0 CH3 0 represents. 5. Materials according to one of claims 1 to 4, characterized in that their fluorosilane content is 1.0 to 20, preferably 2 to 10 wt .-%. 6. Materials for dental purposes based on monomeric and / or polymeric substances or substance mixtures in combination with fluorine compounds, characterized in that they have at least one water-insoluble fluorosilane of the formula as the fluorine compound - CR.- - CH2 - CH2 contain, wherein Rj represents a radical having at most 12 carbon atoms, which is optionally substituted by lower alkyl groups or a vinyl group on the nucleus benzyl or styryl or cyclohexylalkyl, wherein in the cyclohexylalkyl radical the alkyl radical contains 2 to 5 carbon atoms and the cyclohexyl radical by one or two hydroxyl groups and / or lower alkoxy groups or substituted by an epoxy oxygen atom, and R2 and R3, which may be the same or different, Fluorine, represent a hydroxyl group or alkoxy groups in which the alkyl groups contain 1 to 3 carbon atoms or a radical as defined under Rt. 7. Materials according to claim 6, characterized in that the rest Rj in the fluorosilane at least one of the groups - CH C - I. X or / ° \ CH - CH - or - 0H I C -I H wherein X represents hydrogen or a methyl group. 8. Materials according to claim 6, characterized in that Ra represents a / J-cyclohexyl-ethyl radical in fluorosilane, wherein the cyclohexyl radical in positions 3 and 4 by two hydroxyl groups, a hydroxyl group and a lower alk- 55 oxy group or is substituted by an epoxy oxygen atom. 9. Materials according to one of claims 6 to 8, characterized in that their fluorosilane content is 1.0 to 20, preferably 2 to 10 wt .-%. Dental caries is one of the most common diseases today, especially in the industrialized nations. It is known that it is related to the high sugar consumption and consumption of sugary foods. The development of caries has largely been clarified by intensive research in recent times. The formation of demineralized zones in enamel and dentin, the dental hard tissues, is closely related to the formation and presence of the glue-like, tough dental plaque. These arise through the action of microorganisms, mainly on sucrose, formation of glucose and reconstruction to dextrans. The plaque forms an ideal breeding ground for streptococci, which break down glucose to aliphatic acids such as lactic acid, acetic acid, etc. The hard tooth substances become due to the acid attack 3rd 625 120 demineralized so that defects arise which can only be achieved by drilling out the carious dentin and filling the cavity with suitable materials, e.g. Amalgam, dental cements, etc. can be remedied. The frequency of caries defects also depends heavily on oral hygiene. The research showed that the fluorine content of the tooth enamel continues to play an important role and that by incorporating fluorine ions into the lattice of the hydroxyapatite with the formation of fluorapatite, so-called enamel hardening is possible and thus there is better resistance to the attack of acids. In this way it is possible to reduce the susceptibility to caries. It has been taken into account by fluoridating drinking water, using fluorine compounds in toothpastes, mouthwashes and the like. Of the numerous proposed fluorine compounds, preference is given to alkali metal fluorides, tin fluorides, sodium fluorine monophosphate and organic fluorine compounds, in particular amine fluorides. In addition to general caries, dimple and fissure caries play an important role on the molar chewing surface. An attempt has been made here to have a prophylactic effect by using fluorine-containing lacquers or by sealing the fissures. The fluorides used are water-soluble and are applied to the tooth enamel in dissolved form (toothpaste, mouthwash, varnish). The disadvantage of these water-soluble fluorine compounds is that they are diluted relatively quickly by the saliva of the oral cavity and largely washed away again, so that the incorporation of the fluorine ions into the tooth enamel is repeatedly interrupted. 30th Attempts have already been made to cover the fresh fluoride layer with an adhesive varnish which remains on the tooth surface until the fluorine has been stably incorporated into the lattice structure of the tooth enamel. Attempts have also been made to incorporate water-soluble fluorides into plastics (prostheses, 35 artificial teeth, crown and bridge materials, filling and sealing materials) in order to have a reservoir of fluorine ions available which the natural teeth can use for a longer period of time with the necessary dose Fluorine supplied. 40 In this form of application, however, the water-soluble fluorides have major disadvantages. If you install them in plastics, they quickly lose their good strength properties, i.e. they are softened by the saliva and the bending and compressive strength values drop quickly. The same applies to paints that are attacked, destroyed and washed away shortly after their application. In addition, the distribution of the salt-like fluorides in the hydrophobic plastic or lacquer is irregular, since they are not dissolved, but only dispersed. This causes the 50 - CH = C - or I X wherein X represents hydrogen or a methyl group. With the help of these groups, the fluorosilanes can be chemically incorporated into the desired product when using the dental materials, e.g. They can be used as comonomers with the monomeric and / or oligomeric substances or as grafting monomers with the polymeric substances, so that homogeneous copolymers 65 or graft copolymers are obtained. In particular, R, in fluorosilane, could give a fluorine ion, possibly through lower alkyl groups or a vinyl group on the core, only at many small points on the tooth surface and not on a homogeneous layer. It has also been demonstrated that the fluorine ions are only released to the underlying enamel surface from highly water-permeable and thus unstable plastics or paint films, whereas water-impermeable plastics, which naturally adhere much better to the tooth enamel, completely prevent the effect of the fluorides built into them. The object on which the invention is based is to provide materials containing fluorine compounds for dental purposes, in which the fluorine compounds are homogeneously distributed and have a permanent cariostatic effect on the tooth enamel due to the constant elimination of fluorine ions. Furthermore, the dental materials for prostheses, plastic teeth, crowns and bridges, for filling and sealing materials and dental enamel should not lose their good physical properties, such as superior abrasion resistance, low water absorption, small volume changes and great transparency, due to the content of the fluorine compounds.