RU2375039C2 - Dental polymeric composition - Google Patents

Abstract

FIELD: medicine. ^ SUBSTANCE: invention relates to dental materials and can be applied as filling material for restoring and restoration of anatomical tooth form. Dental polymeric composition, contains methacrylic derivatives of polyacryloxyphosphazene, bisphenolglycidylmethacrylate (Bis-GMA), triethyleneglycol dimethylacrylate (TGM), ionol, camphoroquinone, 4-ethyldimethylaminobenzonate, aerosyl and barium glass filler with definite components ratio. Methacrylic derivatives of polyacryloxyphosphazene have general formula , in which Ar - diphenylpropane radical; R - methacrylic radical; n - integer from 1 to 100. ^ EFFECT: composition is stable at storing, has high strength characteristics, low water sorption and water solubility. ^ 3 cl, 2 ex, 1 tbl

Description

The invention relates to dental materials and can be used as a filling material for restoration and restoration of the anatomical shape of the tooth.

,Composite dental materials are known (US patent No. 4579880 of 08/01/1986, taken as a prototype), which include polymerization-capable methacrylate oligomers, for example triethylene glycol dimethacrylate (THM), chemical polymerization activators, fillers, for example silanized silica powder, an inhibitor (monomethyl ether) hydroquinone) and polymerization-capable phosphazene monomers of the general formula

,

where one of the radicals R ₁ and R ₂ (or both) contains at least 3 carbon atoms and is capable of copolymerization with acrylic monomers.

Specified in the prototype phosphazene monomers are added in an amount of from 20 to 70 wt.% To improve the physico-mechanical characteristics of the composition and obtained, as indicated in the prototype (example No. 1), by the interaction of hexachlorocyclotriphosphazene (HCF) with β-hydroxyethyl methacrylate in the presence of pyridine. As is known from the literature, pyridine itself is able to react with HCF with destructive cleavage of the cycle. When analyzing NMR ³¹ P-spectra of the prototype phosphazene monomer, we found that instead of the expected singlet (hexazubstituted HCF) or a signal system of type A ₂ B (five to eight lines), the spectrum of the phosphazene monomer of the prototype is a complex system with a predominance of signals of the phosphorus atom in groups P = O and P-OH. In addition, the phosphazene monomers obtained from the prototype are alkoxy derivatives of HCF with a carboxyl group in the β-position, which are extremely unstable substances that easily undergo a phosphazene-phosphazane rearrangement with further destruction of the phosphazene cycle.

Therefore, the main disadvantage of the polymerization-capable phosphazene monomers proposed in the prototype is their instability, which leads to instability of dental compositions containing such monomers, especially during long-term storage, including by reducing their compatibility with other components of the composition.

The objective of the invention is to create a storage stable dental polymer composition, while having high strength properties, low water absorption and water solubility.

A polymer composition is proposed comprising a mixture of polymerization-capable methacrylate oligomers, polymerization activators, inhibitors, fillers and polymerization-capable phosphazene compounds, namely methacrylic derivatives of polyaryloxyphosphazene (PAF) of the general formula

The novelty of the proposed composition is that:

- in the above formula, Ar is an aromatic radical, preferably diphenylolpropane; R is an unsaturated organic radical capable of homo- and copolymerization with the opening of a double bond, preferably methacrylate; n is an integer from 1 to 100;

- methacrylic derivatives of PAFs are prepared by reacting diphenylolpropane phenolates with hexachlorocyclotriphosphazene (HCF) in tetrahydrofuran medium followed by converting the resulting polyaryloxyphosphazene to the phenolate form and reacting with methacryloyl chloride;

- a mixture of bisphenol glycidyl methacrylate (Bis-GMA) and triethylene glycol dimethacrylate (THM) is used as the polymerization-capable methacrylate oligomers. Selected methacrylate oligomers in combination with methacrylic derivatives of PAFs provide strong, chemically stable spatially crosslinked polymer structures;

- as the polymerization activator, a photoinitiating system is used, for example, a mixture of camphoroquinone and 4-ethyl dimethylaminobenzoate, which allows the polymerisation of the composition with blue light at a wavelength of 450-500 nm for 20-40 seconds versus 1-2 minutes in the prototype. The components that make up the photoinitiating system are well compatible and stable during storage, which makes it possible to produce a dental composition in the form of a single paste, unlike the prototype, which provides for the preparation of two pastes for the separation of the activator and the chemical polymerization inhibitor;

- fillers use mixtures of highly dispersed silanized inorganic fillers based on oxides of silicon, aluminum, barium, magnesium or others, for example aerosil (particle size 7-40 nm) and silanized barium glass filler (particle size 0.4-5.0 μm). This combination of fillers with different particle sizes allows for dense "packing" of particles in an oligomeric matrix, a high level of filling of the composition, and hence high physical and mechanical properties;

- the composition of the proposed dental polymer composition of these components are included in the following ratios (wt.%):

Bisphenol Glycidyl Methacrylate (Bis-GMA) 7-18 Triethylene glycol dimethacrylate (THM) 5-13 Methacrylic derivatives of polyaryloxyphosphazene (PAF) 1-5 Ionol 0.001-0.005 Camphoroquinone 0.05-0.5 4-ethyldimethylaminobenzoate 0.05-0.5 Aerosil 0.5-10 Barium glass filler up to 100

Compliance with the criterion of "inventive step" is confirmed by the signs:

- as polymerization-capable phosphazene compounds, methacrylic derivatives of polyaryloxyphosphazene (PAF) of the general formula are used

in which Ar is an aromatic radical, preferably diphenylol propane; R is an unsaturated organic radical capable of homo- and copolymerization with the opening of a double bond, preferably methacrylate; n is an integer from 1 to 100.

The advantage of the methacrylic derivatives of PAFs that make up the proposed polymer composition is their stability, they are not capable of phosphazene-phosphazane rearrangement and are more thermally stable. They are better compatible with basic dental compositions, for example, containing bisphenol glycidyl methacrylate. The functionality of the proposed methacrylic derivatives of PAF can be varied within wide limits, changing both the number of unsaturated groups R in the component link and the chain length (number n). The proposed methacrylic derivatives of PAFs are, in fact, reinforcing nanofillers, strongly bonded to the base composition due to copolymerization over unsaturated groups R. The length of these reinforcing "nanofibers" can be controlled by the value of n specified in the synthesis.

An additional advantage compared with the prototype is that it is sufficient to introduce the proposed methacrylic derivatives of PAF in a small amount of 1-5% into the basic dental composition, which allows to obtain spatially crosslinked polymer structures with reduced water absorption, water solubility and increased strength characteristics. In the prototype, the introduction of phosphazenes 20-70%.

It is especially important that the resulting dental composition has good stability properties during long-term storage (more than two years). The table shows the physico-mechanical characteristics of a dental polymer composition that does not contain methacrylic derivatives of PAF (example 1) and contains methacrylic derivatives of PAF (example 2), confirming the stability of the proposed composition.

Preparation of a dental polymer composition

Example 1

In a vacuum homogenizer, a composition of the following composition is prepared, wt.%:

Bisphenol Glycidyl Methacrylate (Bis-GMA) 13,085 Triethylene glycol dimethacrylate (THM) 8,730 Ionol 0.005 Camphoroquinone 0.130 4-ethyldimethylaminobenzoate 0.130 Aerosil OX-50 (average particle size 40 nm) 2,080 Barium glass filler SCHOTT-8235 (average particle size 0.7 μm) 75,840

Obtained in the form of a paste, the dental polymer composition is placed in a sample preparation mold, irradiated for 40 seconds with a wavelength of 400-500 nm using an apparatus for light curing of dental materials. Cured samples of the dental polymer composition are immersed in distilled water and incubated in a thermostat at a temperature of 37 ± 2 ° C for 24 hours. At the end of the exposure of the samples under these conditions, they are subjected to tests according to the methods of GOST R 51202-98.

Example 2

In a vacuum homogenizer, a composition of the following composition is prepared, wt.%:

Bisphenol Glycidyl Methacrylate (Bis-GMA) 12,595 Triethylene glycol dimethacrylate (THM) 8,400 Methacrylic derivatives of polyaryloxyphosphazene 3,750 Ionol 0.005 Camphoroquinone 0.125 4-ethyldimethylaminobenzoate 0.125 Aerosil OX-50 (average particle size 40 nm) 2,000 Barium glass filler SCHOTT-8235 (average particle size 0.7 μm) 73,000

Obtained in the form of a paste, the dental polymer composition is placed in a sample preparation mold, irradiated for 40 seconds with a wavelength of 400-500 nm using an apparatus for light curing of dental materials. Cured samples of the dental polymer composition are immersed in distilled water and incubated in a thermostat at a temperature of 37 ± 2 ° C for 24 hours. At the end of the exposure of the samples under these conditions, they are subjected to tests according to the methods of GOST R 51202-98.

The stability of the composition according to example 2 is confirmed by the verification of its physical and mechanical properties over time (at different intervals from the date of manufacture of the composition), presented in the table.

The method of producing polymerization-capable methacrylic derivatives of polyaryloxyphosphazene PAF.

A solution of diphenylol propane in ethanol is added to a solution of sodium ethylate in anhydrous ethanol, and after a 15-minute boiling of the mixture, the alcohol is distilled off on a vacuum rotary evaporator. The ratio of sodium ethylate / diphenylolpropane is selected from the desired ratio of the resulting sodium and mono- and diphenolates of diphenylolpropane in the final mixture.

This mixture is extracted with water, filtered from the remaining diphenylol propane, and water is distilled off from the aqueous solution on a vacuum rotary evaporator. In the residue, a mixture of diphenylolpropane mono- and diphenolates is obtained in the ratio necessary to achieve a predetermined value of n.

To a suspension of a mixture of phenolates in tetrahydrofuran (THF), a solution of HCF in THF in molar ratio of sodium phenolate: HCF = 8: 1 is poured with stirring. The reaction mixture is boiled for 9 hours, cooled, filtered off from the resulting sodium chloride and removed from the THF solution. In the residue, polyaryloxyphosphazene (PAF) with M _n from 9000 to 20,000 is obtained. The residual chlorine content in PAF is 2-5%, which corresponds to the presence in their composition of a certain amount of tetra- and pentazubstituted phosphazene cycles.

The obtained PAF is converted into the phenolate form by treatment with sodium ethylate:

The calculated amount of methacryloyl chloride is added dropwise to a suspension of the sodium derivative of PAF in THF, stirred for 1 hour, sodium chloride is filtered off and THF is distilled off. The product is dissolved in chloroform, washed with water and the solution is dried with anhydrous sodium sulfate.

After removal of chloroform in vacuo, a methacrylic derivative of PAF with M _n 20000 and M _w 250000 is obtained.

The resulting product is characterized by the presence of ³¹ P NMR signals in the region of 9.8 ppm. (hexasubstituted triphosphazene rings), as well as groups of the AB ₂ system in pentasubstituted rings.

Table Physico-mechanical characteristics of polymer compositions Composition Destructive stress in compression (σ _squ ), MPa Bending stress
(σ _of ), MPa Water absorption, mcg / m ³ Water solubility, mcg / m ³ Example 1 290 96 14.2 3.0 Example 2 Right away 430 140 8.5 0.5 After 6 months 431 138 8.2 0.4 After 16 months 428 141 8.6 0.5 24 months later 428 139 8.4 0.5

The results of the tests of the samples of the dental polymer composition of the claimed composition shown in the table showed that the developed material has increased strength characteristics, reduced water dissolution and water absorption and exhibits stability of storage properties.

Claims (3)

1. Dental polymer composition containing polymerization-capable methacrylate oligomers, polymerization activators, an inhibitor, fillers and polymerization-capable phosphazene compounds, characterized in that methacrylic derivatives of polyaryloxyphosphazene of the general formula are used as polymerization-capable phosphazene compounds

in which Ar is a diphenylol propane radical; R is a methacrylate radical; n is an integer from 1 to 100, while the dental polymer composition contains wt.%:
Bisphenol Glycidyl Methacrylate (Bis-GMA) 7-18 Triethylene glycol dimethacrylate (THM) 5-13 Methacrylic derivatives of polyaryloxyphosphazene 1-5 Ionol 0.001-0.005 Camphoroquinone 0.05-0.5 4-Ethyldimethylaminobenzoate 0.05-0.5 Aerosil 0.5-10 Barium glass filler up to 100 2. The dental polymer composition according to claim 1, characterized in that the mixture of bisphenol glycidyl methacrylate (Bis-GMA) and triethylene glycol dimethacrylate (THM) acts as the polymerization-capable methacrylate oligomers, the polymerization activator is a photoinitiating system - a mixture of camphoroquinone and 4-ethynomethylate ionol, and as a filler, a mixture of aerosil and barium glass filler with different particle sizes is used. 3. The dental polymer composition according to claim 1, characterized in that the methacrylic derivatives of polyaryloxyphosphazene are prepared by reacting diphenylolpropane phenolates with hexachlorocyclotriphosphazene (HCF) in tetrohydrofuran medium followed by conversion of the resulting polyaryloxyphosphazene to the phenolate form and reaction of methacrylochloride.