JPS5936602B2 - Processing materials for teeth - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dental material comprising polymerizable monomers and/or polymers suitable for dental applications and a finely divided filler.

Processed materials for teeth include, for example, cavity filling materials, fixed cements, temporary sealing and protective covering materials, crown prosthetic denture materials, denture base materials, and artificial teeth whose main components are polymerizable monomers and/or polymers. means a substance for manufacturing.

Monomers or polymers suitable for dental applications include, for example, polyvinyl chloride, polystyrene and their copolymers, polyamides, epoxy compounds, polyurethanes, especially the monomeric and polymeric acrylates and methacrylates [Ullmans Enticlopedii der. Tehinisien.

Hemi (UllmannsEn2yklo-diede
rTechnischenChemie), Volume 5, 1
954, pp. 717-721]. Artificial teeth or tooth parts are usually produced from polymethacrylates in the form of bead or chip polymers, which can be processed in the customary manner by heating in molds with addition of the corresponding monomers.

Mixtures of monomeric methacrylates and polymeric methacrylates are used, for example, as denture base materials, crown prosthetic bridge materials, and the monomers contained in the mixture are completely polymerized in the presence of the polymer. The monomers alone are usually used as fixing cements, temporary sealants and protective coverings, and also as filling materials. In the following, we will mainly discuss denture base materials and filling materials, since special problems exist with these processed materials.

During the polymerization of the commonly used monomers acrylic or methacrylic esters, significant shrinkage occurs. For this reason, a slurry consisting of bead polymer and monomer (weight ratio 2:1) has been used very easily in the production of denture base materials. In this case the concentration is still 7%. Furthermore, in this case there is a high coefficient of linear expansion (TK) of 81.0 x 10-6 m/Mm/°C. In comparison, the TK of natural teeth is only about 1/8 of that, ie, 11.4 x 10-6. Long chain monomers based on bisphenol A and glycidyl methacrylate were most recently disclosed in U.S. Pat.
66112, it was first used as a tooth filling material and for similar purposes. This new monomer (hereinafter abbreviated as bis-GMA) has a small shrinkage rate. To further reduce shrinkage, the monomer is further mixed with about 3 parts by weight of an inert inorganic filler. In other words, is this a combination? about 25% of a cold polymerizable monomer mixture;
inorganic fillers, preferably aluminum and silicon oxides,
or about 75% of silicate glass or calcium carbonate (in various shapes such as spherical and fibrous). This not only reduces the above-mentioned polymerization shrinkage to a level that is acceptable for all applications, e.g. about 1%, but also
The TK also decreases to about 20 to 30 x 10-゜rei/lrei/℃. Instead of the monomer bis-GMA, this binder mixture may also contain other derivatives of bisphenol A or urethane derivatives, for example produced by addition from diisocyanates and hydroxyalkyl methacrylates.
- Generally short-chain methacrylic acid esters and/or known cross-linking agents such as triethylene glycol dimethacrylate are added to reduce the viscosity. Fillers are generally produced by mixing together two pastes, each containing a binder and a filler.

Redox systems (e.g. peroxide amines) used in polymerization reactions require one paste to contain only the peroxide catalyst;
The other paste is also proportioned to contain an amine initiator. The inorganic filler is coated with silane before mixing, ie coated with a suitable unsaturated silane compound, to improve its bonding to the organic matrix.

Known as a composite material, this material, with a filler content suitable for the intended use, is suitable for filling the cavities of anterior teeth, as a fixing cement, for fissure sealing and as a protective tooth covering. It is used to prevent dental caries, and as a denture material for crown prosthetics. However, it has been found that although these processed materials generally have very good mechanical properties, they are significantly inferior in abrasiveness and, moreover, often have insufficient transparency.

Attempts have therefore been made to improve the polishing properties by using finely divided inorganic fillers with a diameter not larger than about 30 microns (see DE 21 26 419). However, by making the particles finer, the transparency deteriorates significantly. This surface is initially uneven and becomes rough after a short time due to uneven wear, causing discoloration. When the particle size of the inorganic filler particles is reduced to a minimum of about 0.8-8μ and a maximum of about 3-20μ (West German Patent Application No. 2312258)
However, the abrasiveness and transparency of tooth filling materials are still insufficient. Furthermore, West German Patent Application Publication No. 192883
No. 1 and West German Patent Application Publication No. 2126,41
No. 9, No. 2164668 and No. 2224683, in addition to inorganic fillers commonly used in tooth filling materials,
It is known that silicon dioxide can be added in amounts of up to 8% by weight, based on the total weight of the tooth filling material. However, the addition of silicon dioxide with the above-mentioned particle size only has the purpose of thickening the monomer and thereby preventing precipitation of relatively large filler particles. German Patent Application No. 2164668 points out that particles smaller than 0.7 μm must be removed by a suitable method. This is because particles of this type significantly reduce the transparency of the filling material. Further, in West German Patent Application Publication No. 2126419, it is stated that silicon dioxide with a particle size of 50 to 2000λ used as a thickening agent is about 5% of the total amount.
It is suggested that it should be used only in small amounts of ~8% by weight. The disadvantages described in this document when using silicon dioxide with a particle size smaller than 1 μm are due to the use of silicon dioxide in conjunction with larger amounts of larger particle size fillers.

Surprisingly, however, it has been found that when using inorganic fillers with particle sizes smaller than 400 mμ, it is possible to improve the mechanical properties as well as the polishability of processed materials used for dental purposes without impairing their transparency. found.

According to the invention, therefore, the dental material contains polymerizable monomers and/or polymers suitable for dental applications in an amount of from 10 to 90%, based on the weight of the additive material, and from 10 to 40%.
and a fine inorganic filler having a particle size in the range of 0 mμ.

Advantageously, at least 50% of the finely divided inorganic filler particles are 10
It has a particle size in the range ~40 mμ.

The finely divided inorganic fillers make the monomer viscous and give the material thixotropic properties, so that the processed material can be easily reliquefied by stirring. When using highly viscous monomers and monomer-polymer mixtures, it is advantageous to add finely divided inorganic fillers in small amounts within the ranges mentioned, so that the mixture does not become too viscous.

However, the amount of finely divided inorganic filler can also be determined in the case of monomers or mixtures with higher starting viscosities, such that their specific surface area is
It can be increased by selecting fillers smaller than 0i/7. The specific surface area of this type of fine filler is approximately 3
It is preferable that it is 0-80m1/7. The amount of finely divided inorganic filler is advantageously in the range from 20 to 80%, preferably from 40 to 75%, based on the total weight of the processed material.

The most preferred range depends, as mentioned above, in particular on the specific surface area of the filler and the viscosity of the polymerizable monomer and/or polymer. The finely divided inorganic filler is preferably silicon dioxide and/or aluminum oxide. It is also possible to use glasses such as borosilicate glasses, lithium aluminum silicate glasses, glasses containing barium oxide or lanthanum oxide, and similar fillers, provided that their particle size is smaller than 400 mμ. . Mixtures of finely divided fillers can also be used, in which case the glass preferably has a low coefficient of thermal expansion and is added in an amount of up to 25% by weight of the total filler. Fine fillers are, for example, trimethoxy-(3-
It is preferably coated with silane by treatment with (methacryloyloxypropyl)-silane.

This silane coating is carried out in a conventional manner using a silane having a polymerizable organic group. The polymerizable groups react with the polymerizable monomers of the organic matrix, thereby creating a strong bond between the organic component of the material and the inorganic filler. Coating the fine inorganic fillers used in the present invention with silane is not absolutely necessary, unlike the crude fillers used heretofore. The color of the tooth material according to the invention can be matched to the color of natural teeth by adding organic or inorganic coloring pigments and/or opacifying agents.

The particle size of such additives should not be larger than 400 mμ. Furthermore, the invention relates to artificial teeth and partial tooth replacement materials, such as tooth fillings, dental crowns, bridges (in particular their shells), veneers and similar replacement parts manufactured from the tooth processing material according to the invention. Regarding.

Due to the presence of fine inorganic fillers in the proportion of 20 to 80% by weight of the processed material, this tooth processed material has an exceptionally high pressure resistance, excellent transparency, and an extremely smooth and uniform final surface. It can be used to make things.

The differences in surface quality that exist between commercially available materials, such as filled materials and those containing fine mineral fillers, can be observed with the naked eye. This difference is even more clearly seen under the microscope. Subtle? In the case of fillers containing fillers, individual particles are not visible (their surface appears as a homogeneous unit), but in the case of commercially available fillers, individual particles can be observed in the form of fragments or spheres. By using fine fillers, it is possible to overcome the conventional difficulties in obtaining high transparency and good polishability at the same time. Furthermore, the tooth processing material according to the present invention has opalescence. This fact represents an important improvement in terms of cosmetic effects.
This is because this resin layer is yellow in transmitted light and bluish-white in incident light, as in the case of natural teeth. The processed material according to the invention is therefore particularly suitable as an anterior tooth filling material. Good results have been obtained using the following polymerizable monomer binders: mono-, di- and higher esters of methacrylic acid, especially bis-GMA (which optionally contains dilutable monomers, such as methyl methacrylate). can be obtained more advantageously by using Other examples of monomeric binders include bis-[4-(
2-Hydroxy-3-methacryloyloxypropoxy)-phenyl]-dimethylmethane, 2,2-bis-[4
-(2-hydroxyethoxy)-phenyl]-propane dimethacrylate and triethylene glycol dimethacrylate. However, it is also possible to use other derivatives of bisphenol A or reaction products of hydroxyalkyl methacrylates and isocyanates. This monomer often has a relatively high viscosity, so in order to reduce this viscosity further short-chain monomeric methacrylic esters are generally added. Difunctional esters of acrylic acid or methacrylic acid can be added as cross-linking agents. Inorganic fillers are fine fillers. As polymerization catalysts, for example organic peroxides such as dibenzoyl peroxide, tert-butyl peroctoate or azo compounds such as 2,2'-azobisisobutylonitrile (AI
BN) can be added.

Also, for example, dibenzoyl peroxide/dimethyl-p-
It is also possible to use redox systems customary for dental plastics, such as toluidine or dibenzoyl peroxide/trimethylbarbituric acid. So-called composite materials consisting of two separately stored components A and B, preferably in paste form, can also be produced for filling and other purposes. Both contain an organic binder system and a filler; furthermore, one of the components contains a catalyst and the other an activator. The amount of inorganic filler to be added can also be changed depending on the purpose of use. For example, in the case of composite materials for filling, this is 60
~65% and the organic host is bis-GMA2
O~22% and ethylene glycol dimethacrylate 1
It consists of 5-18%. The organic binder mixture is intimately mixed with the finely divided inorganic filler until a pasty substance results.

The first component additionally contains zero benzoyl peroxide.
．． 5-2% and 0.5-1% dimethyl para-toluidine are added to the second component. Test specimens are prepared by taking approximately equal amounts of pastes A and B and mixing them in a mixing proc.

In contrast to the usual filling materials, it is also possible to use a metal spatula. The processing time of the material is approximately 2 minutes,
After 5 minutes the mixture polymerizes into a solid specimen. The measured compressive strength is between 4000 and 6000 kg/Cd, depending on the amount of fine filler used and the variation of the organic matrix, which is better than that of amalgam. Horizontal crushing strength is 11-16kg
/1, and the water adsorption is 0.5 to 1.5 after 2 months.
%.

The surface quality of the commercially available filler material and the filler material prepared as described above are compared under a microscope, before the surfaces of both are polished in a conventional manner to produce optical selection. In this case, the filling material with fine fillers has a homogeneous and completely non-porous surface, whereas in the case of commercially available filling materials it is observed that individual fragment-like or spherical particles are embedded in the matrix. . Another unexpected effect is that the fine filling material exhibits an opalescent appearance, i.e. yellow in transmitted light and bluish-white in incident light, and thus corresponds well to the optical properties of natural tooth enamel, especially between the anterior teeth. This is extremely favorable for filling. Furthermore, finer filling materials can be used to produce significantly improved workpieces for crowns, inlays and bridges.

For this purpose, for example, the crystalline dimethacrylate of modified bisphenol A is dissolved in an organic solvent, for example chloroform or ether, and the finely divided filler is added to this solution with continuous stirring. This gives a paste, which is kneaded until the solvent is completely evaporated. The powder is ground in a ball mill and eg benzoyl peroxide is added as a catalyst. After sieving the mixture, a material suitable for manufacturing dental crowns and bridges is obtained. For example, a dental crown is manufactured as follows.

The powder thus produced is heated in a porcelain colander above the melting point of the crystalline monomer to produce a dilute liquid slurry that can be processed with a brush or spatula. If the slurry is applied in layers to separate tooth impressions and the layers are polymerized, for example in a stream of hot air, dental crowns with excellent clarity and extremely high wear resistance are obtained. However, the dental crown can also be polymerized in conventional manner from a polymer/monomer slurry to which appropriate amounts of fine fillers have been added by layering in a dental flask and heating in a water bath. Furthermore, the fine filler is mechanically mixed with beaded polymethyl methacrylate, and the slurry obtained by adding monomer is polymerized while being pressed in a metal mold at an elevated temperature, e.g. 100°C, to form an artificial tooth or A vestibule can also be molded.

The teeth produced in this way had very good gloss, good physical properties such as compressive strength and transverse fracture strength, and were clearly superior to conventional materials.

The fine filler is made extremely uniform by making a slurry from the monomer methyl methacrylate and the fine filler, polymerizing it under pressure and elevated temperature to form a block, and then crushing it to form a chip polymer. can be distributed in polymers.

The polymer thus obtained can be mixed with fillers and used in the customary manner for the production of artificial teeth or tooth parts or as a base material for dentures. In general, fine fillers can be used to obtain improved dental materials, which have significantly higher compressive strength, good polishability, excellent transparency and low abrasion resistance, and whose gloss is Comparable enough to the appearance of natural tooth enamel.

The tooth processing material according to the invention gives good results in the production of tooth filling materials and is also suitable for the production of dental crowns, bridges, prefinished veneers or artificial teeth; At least the outer layer of the artificial tooth is manufactured from the tooth processing material according to the present invention.

Next, the present invention will be explained in detail based on Examples.

For example, silicon oxide (average particle size 10-20 mμ, specific surface area 50μ/
7) Silanize 61.57 using methacryloxypropyltrimethoxysilane in the conventional manner and shake in a laboratory kneader.

To this are added Bis-GMA 227 and 16.5 y of ethylene glycol dimethacrylate and the mixture is kneaded until a uniform, spot-free paste results. This paste 4
0.67 of 50% benzoyl peroxide is added to 407 (paste A), and 0.17 of dimethyl para-toluidine is added to main paste 407 (paste B). When equal amounts of pastes A and B are mixed in a mixing block, a material suitable for filling tooth cavities is obtained.

The treatment time is 2 minutes and the material hardens after 5 minutes. Specimens are prepared in this way and stored in water at 37° C. for 24 hours. The above specimen and a comparative specimen made from a commercially available composite material for tooth filling (approximately 75% SiO2, average particle size 3
0μ) for 5 minutes using a rubber polisher.

Examine the surfaces of both specimens under a microscope. As a result, the polished surface image of the material containing fine silicon dioxide shows a uniform, smooth, non-porous surface, but in the case of commercially available materials, it is clearly recognized that individual particles are distributed within the matrix. The following table shows some comparative values.

Example 2 2,2-bis-[4-(2-hydroxy-ethoxy)-
Phenyl]-propane dimethacrylate 20y is dissolved in chloroform 50y.

Silane-coated silicon dioxide 217 with an average particle size of 30 mμ and a specific surface area smaller than 80rr1/7 is added to this solution.
Add. The paste thus produced is dried with continuous stirring until the crystalline monomer solidifies again and the solvent evaporates. In this way, the silicon dioxide is completely uniformly distributed in the monomer. 0.5% benzoyl peroxide is apportioned to the powder by grinding in a Bonoremill and subsequently sieving.

This mixture is stable unless heated above 42°C.
For processing, the powder was melted in a porcelain colander at 50 to 6°C,
It is applied in layers with a brush or spatula onto separate tooth impressions, each layer being polymerized at approximately 150° C. in a stream of hot air. The dental crowns thus obtained are compared with dental crowns manufactured from commercially available materials. The tooth crown with finely divided fillers has an opalescent appearance, ie it appears bluish-white in the incident light and therefore cosmetically closely resembles natural tooth enamel.

When both crowns were tested by brushing them with purified chalk using a toothbrush, the polymer containing fine silicon dioxide was clearly more wear resistant. This difference is evident from some comparative values: Example 3 The finely divided filler (but not silane coated) 100f7 used in Example 1 was mixed with unpigmented polymethyl methacrylate 30V in the form of a bead polymer as well as 50% benzoyl peroxide. Mix with 2y.

A monomer mixture is prepared consisting of 35% monomer methyl methacrylate and the reaction product 35y of hydroxyethyl dimethacrylate and hexamethylene diisocyanate.

The powder and liquid are mixed mechanically in a closed container using a vibratory mixer until a viscous slurry forms. This slurry was packed into tooth shapes and polymerized at 110° C. for 4 minutes. The artificial tooth thus obtained exhibits a clear opalescence, ie it is yellow in transmitted light and turns bluish-white in incident light. Its indentation hardness is 2800k9/Cwi, while a comparative tooth made with commonly used methacrylate as its main component has a hardness of 14
00kg/Cd. The stability of artificial teeth containing fine fillers is clearly better compared to monomers, chloroform or boiling water. , the invention will now be explained with reference to the drawings: 1st
The figure shows a longitudinal sectional view of the artificial tooth.

FIG. 2 is a sectional view taken along the line A-A in FIG. 1, and as is clear from FIG. 2, this tooth has a core 1 made of plastic without filler and an outer layer 2 made of the tooth material according to the invention. and has. FIG. 3 shows an anterior dental crown manufactured from the tooth material according to the invention. Embodiments of the present invention and related matters are listed below: (1) Processing according to the claims, characterized in that at least 50% of the fine inorganic filler components have a particle size within the range of 10 to 40 mμ. material.

(2) The processed material according to claim 1 or the above item 1, wherein the amount of the fine inorganic filler is within the range of 40 to 75% based on the weight of the processed material. (3) The scope of the claim or the above-mentioned item 1~ characterized in that the fine inorganic filler is made of silicon dioxide, aluminum oxide, or glass.
Processed material according to one of clauses 2.

(4) The processed material according to item 3 above, wherein the fine inorganic filler is made of borosilicate glass, lithium aluminum glass, or glass containing barium oxide or lanthanum oxide.

5. Processed material according to claim 3 or 4, characterized in that, in addition to the fine silicon dioxide filler, further fine glass is present in an amount of up to 25% by weight of the total filler content.

(6) A claim characterized in that a fine inorganic filler is coated with silane or one of the above-mentioned items 1 to 5.
Processing materials listed in .

(7) The processed material according to item 6, wherein the fine filler is silane-coated with trimethoxy-(3-itacryloyloxypropyl)-silane.

(8) The ester as a polymerizable monomer binder is bis-[4-(2-hydroxy-3-methacryloyloxypropoxy)-phenyl]-dimethylmethane or 2.
Processed material according to claim 1 or one of the preceding claims, characterized in that it is 2-bis-[4-(2-hydroxyethoxy)-phenyl]-propane dimethacrylate.

(9) The processed material according to claim 1 or one of the items 1 to 8, characterized in that it contains a colored pigment and/or an opacifying agent.

al Processed material according to the claims as actually described in Example 1 or 2.

al) An artificial tooth manufactured from the tooth processing material according to the claims or one of the above items 1 to 10.

A replacement member for a part of a tooth manufactured from the tooth processing material according to the claims or one of the above items 1 to 10.

(Self) An artificial tooth and a replacement member for a part of the tooth, having an outer layer manufactured from the tooth processing material according to the claims or one of the above items 1 to 10.

[Brief explanation of the drawing]

Figure 1 is a schematic vertical cross-sectional view of the artificial tooth, and Figure 2 is A--A in Figure 1.
A schematic cross-sectional view along line A, FIG. 3 is a schematic view of the veneer crown. 1...Nuclear, 2...Outer layer.

Claims (1)

[Claims] 1. In a tooth processing material containing at least one polymerizable monomer acrylate or methacrylate and a fine inorganic filler, (a) as the acrylate or methacrylate, (i) an acrylic ester or methacrylic ester of a dihydroxy or polyhydroxy organic compound; ,
(ii) a reaction product from a hydroxyalkyl methacrylate and a diisocyanate, or (iii) the above (i)
) and (ii), and (b) as an inorganic filler, the particle size is 10 to 400 mμ and the specific surface area is 20
A processed material for teeth, characterized in that it contains a fine inorganic filler smaller than 0 m^2/g in a proportion of 20 to 80% by weight of the processed material.