DE2914537A1 - METHOD OF MANUFACTURING TOOTH CROWNS FROM PLASTIC - Google Patents

Description

- ⁴ - 29H537

The invention relates to a method for the simple and rapid production of high quality dental crowns under Use of special photo-curable resin or synthetic resin mixtures. The invention relates not only to the manufacture of dental crowns made entirely of resin material consist (jacket crowns made of resins or synthetic resins), but also on the production of metal crowns with a Resin layer are coated. The present invention is therefore also applicable to the manufacture of large dental bridges.

In the manufacture of synthetic resin dental crowns, the box casting and coating processes are known in particular. So far, the coating process has been of particular interest. which is easier for technical reasons. For example, in U.S. Patents 3,470,615 and 3,471,596, the coating method exists therein, first a polymerizable powder and a polymerizable liquid component together to mix into a slurry, to apply this mixture to a metal frame and to shape it, to prepolymerize the mixture by means of a jet of hot air and finally the product obtained to burn at high temperature. In such a known method, however, a thin layer must be repeated applied from the mixture and treated with a hot jet to allow complete polymerization of the slurry mixture , i.e. this process is time-consuming and labor-intensive. The scope of education of bubbles, sores during polymerization and the Shrinkage due to the thermal treatment depends to a large extent on the experience of the worker in applying in layers of the mixture so that, for example, cracks and peeling may occur. With some resin materials used the wear and tear resistance are not good, and water-absorbent food residue can easily adhere to the resin material.

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The invention is therefore based on the object of an effective Specify a process for the production of high quality dental crowns from resin material, the properties of which are largely are adapted to those of the property room, the method requiring no extraordinary expenditure of time and effort. According to the invention, a certain, photo-curable Resin mixture used, in particular the photo-curing properties are used.

The method according to the invention is essentially distinguished by first applying a photohardenable resin mixture to a plaster model or to a metallic frame a frontal crown while maintaining the shape of the tooth crown; the photo-curable resin mixture contains a polymerizable methacrylate and / or acrylate and one Photosensitizer and / or a filler. The resin mixture is then uniformly exposed using a actinic radiation cured.

First, a photo-curable one that can be used in the present invention is used Resin mixture described.

It is known that dental technology or dental prosthetic resin materials generally meet the following requirements:

Λ. The material should be transparent or translucent and easy to color in order to enable it to be adapted as precisely as possible to the area of the floor;

2. the material should not discolor after the preparation within ³ ^ or outside of the mouth or bleach;

3 · the material should be used during manufacture or during does not expand, shrink, or deform from use;

4. the strength, elasticity and abrasion resistance should be sufficient for permanent use;

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5. The material should be insoluble in the oral fluid

and are not influenced by them; 6. The material should not absorb any food residues and should be easy to clean like the mouth and teeth; 7 · the material should be tasteless, odorless, non-toxic and not be irritating to the tissues of the pharynx;

8. The specific gravity should be low and the thermal conductivity be high and

9 · the softening point of the material should be significantly higher than the temperature of the food.

Extensive investigations are within the scope of the invention has been carried out to provide the best photocurable resin material which can meet all of the above requirements. Included it has been found that polymerizable methacrylates and / or acrylates best meet these requirements.

Below are the preferred starting materials for preparation of such a polymer listed as a photo-curable resin:

I. polyester-polymethacrylates and / or polyester-polyacrylates,

II. Polyol-polymethacrylates and / or polyol-polyacrylates,

III. Epoxy-polymethacrylate and / or epoxy-polyacrylate,

IV. A reaction product of acrylic acid and / or methacrylic acid with a monoepoxide and an acid anhydride,

V. monomethacrylate and / or monoacrylates with a carboxy! Group in the molecule and having a boiling point of 250 g ⁰ G at Ätmosphärendruck,

VI. Monomethacrylates and / or monoacrylates with terminal ends Ep oxy.gr upp en,

VII. Polyurethane polymethacrylates and / or polyurethane polyacrylates,

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YIII. Polyamide methacrylates and / or polyamide acrylates,

IX. the polymethacrylate and / or polyacrylate of the alcohol adduct of a phenol and an oxide,

X. monomethacrylates and / or monoacrylates and

XI. Oligomers of the above methacrylates and / or acrylates.

These materials can be used according to the intended use can be used individually or in combination.

It is not disadvantageous if a small amount of a polymerization inhibitor is used even after production in the polymerizable methacrylates described above and / or acrylates (hereinafter referred to as resin base material referred to) or if xveniger than 300 ppm of a polymerization inhibitor can be added to improve the durability of the resin system.

Preferably the photosensitizer is used for the polymerizable Methacrylates and / or acrylates selected among others from the following group: benzene, benzoin methyl ether, Benzoin ethyl ether, benzoin propyl ether or Benzoin butyl ether. These materials can be used individually or in ' Combination can be used. Although the amount of photosensitizer added depends on the type of resin base material, the curing speed, the compound ratio of the other additives (such as pigments and fillers), etc. the photosensitizer is generally used in an amount of from 0.2 to 10 percent by weight, preferably from 0.5 to 8 percent Percentage by weight, based on the resin base material.

Furthermore, the curing can be achieved through the use of a peroxide as a catalyst, such as diary peroxides, e.g. benzoyl peroxide, and hydroperoxides, diacyl peroxides, diacyl peroxides and peroxyesters, in addition to the photosensitizer and through supports the utilization of the heat generated by the actinic radiation. It should be noted, however,

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that when using more than 2 percent by weight of the peroxide catalyst "based on the resin base material, the durability of the photo-curable resin will be impaired can. Therefore, if the peroxide catalyst is added, the amount should remain below 2 percent by weight.

The photo-curable resin used in the present invention is obtained one from a uniform mixture and solution of the above additives. A suitable plasticizer can also be used and a suitable dye can be added. In addition, a phenolic substitute such as p-methoxyphenol and 2,6-di-tert-butyl-p-cresol, alc polymerization inhibitor with free remainder to increase the shelf life of the compound during storage.

According to the invention, the photocurable is used for the production of the tooth crown Resin applied and molded. The resin should be in the form of a paste for deforming. According to the invention an organic or inorganic filler is added to the photo-curable resin. Examples of organic fillers are water-soluble or x ^ water-insoluble polymers, such as Methacrylate polymers and / or acrylate polymers, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyl aldehyde, polystyrene, Polyvinyl ethers, polyvinyl pyrrolidone, copolymers of butadiene and acrylonitrile, polyamides, polyester, vinylon, vinylon or silicone synthetic resin; of these fillers can be 5 to 80 percent by weight, based on weight of the resin base material.

Suitable inorganic fillers are glass granulate, aluminum oxide, sintered alumina, aluminum hydroxide, calcium carbonates, clay, crystal quartz, fused quartz, etc. Of these materials are crystal quartz and fused quartz in terms of, for example, mechanical strength, the refractive index and the coefficient of thermal expansion are particularly preferred and are preferred

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used in a proportion of 20 to 80 percent by weight, based on the resin base material. When inorganic fillers are used, the surface of the product "is preferably treated with a silanizing agent in order to increase the affinity for the resin base material after the impurities have been removed by, for example, an acid such as hydrochloric acid. Examples of the silanizing agent are vinylic acid. tris- (ß-methoxyethoxy) -silane. Ύ -methacryloxypropyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, T-glycidoxypropyltrimethoxysilane, T-aminopropyltrimethoxysilane.

The inorganic fillers approach the coefficient of thermal expansion of the photo-curable resin material to that of the teeth or the metal and support the increase the mechanical strength of the resin material. Furthermore, the inorganic filler lasts for a long time the use under the thermal conditions of the pharynx effectively prevents the resin crown from breaking, that in the case of a frontal crown it detaches itself from the metal frame, that water-absorbing residues are taken up and that discoloration occurs.

Organic and inorganic fillers can be used at the same time. Fine silica anhydride (grain size 7 to 4-0 ταμ) can also be added as a thickener for the photohardenable resin mixture and as a precipitation inhibitor for the filler. .

The production of the dental crown according to the invention is described below explained in more detail. According to the recess in the pharynx, a plaster mold and a holding mold are first made; furthermore, a metal frame is manufactured in the manufacture of a frontal crown. After coating the holding mold with a mold release agent a pulpy, photocurable resin mixture, the color of which is similar to that of the tooth,

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applied to the holding form or the metal frame in the case of a frontal crown while maintaining the shape of the tooth crown. The mixture is then irradiated with actinic radiation for curing. With a frontal crown is preferred an xirite pigment such as titanium pigment, the photohardenable Resin mixture added to achieve the natural color of the tooth so that the color of the metal frame is covered will.

Photocuring is done using "an actinic"

Radiation with a wavelength of 3400 A or more. as Light source can, for example, be a quoke via a vapor lamp, a carbon arc lamp, a UV fluorescent lamp, a tungsten lamp, a xenon lamp, an argon glow lamp, a Lamp or sunlight. The for Photohardening time required depends slightly on the type of photohardenable resin mixture (type and mixing ratio resin base material, photosensitizer, etc.), actinic radiation intensity and thickness of the resin mixture, etc. from. With a thickness of the resin mixture of about 2 mm, the photo-curing is within 60 seconds practically completed, whereby excellent dental crowns made of resin material are obtained. If the resin layer to be applied should be much thicker, the resin mixture can be applied repeatedly and photo-cured several times.

Furthermore, according to the invention, the outer surface of the tooth crown obtained can be coated with the liquid, polymerizable methacrylate and / or acrylate containing the photosensitizer, coated and cured by exposure, to get a shiny surface.

As stated above, in the method according to the invention In contrast to the previously known coating process, no repeated and multiple coating and prepolymerization a small amount of a slurry mixture from the liquid and the powdery component

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necessary. The method according to the invention enables the production of tooth crowns by one to three times Applying the resin mixture and exposing it to radiation for a short period of time. Also requires the inventive method no firing for main or JÜTachhardening after photohardening, so that the required The time and effort required is greatly reduced. The obtained resin material dental crown is, for example, in view of the abrasion resistance, the discoloration properties and mechanical strength is excellent.

In the following examples according to the invention the term "parts" is parts by weight and when specifying "percent" by weight percent. 15th

example 1

13 parts of 2,2-bis- ^ 4 ~ (3-methacryloxy-2-hydroxypropoxy) -phenyl / -propane, 1.8 parts of 2,2-bis (4-methacryloxydiethoxyphenyl) propane, 3 »6 parts of trimethyrene propane trimethacrylate, 0.009 parts 2,6-di.-tert.-butyl-p-cresol, 0.3 parts of benzoin methyl ether and 0.1 part benzil mixed and melted. Furthermore, 82 parts of crystal quartz powder with a grain size of less than 20 / µm pretreated with a silanizing agent 2 parts of fine silica anhydride (AEROSIL R-972 from Nippon Aerosil Industry Co.) and a small one Amount of a dye mixed and kneaded to obtain a pulpy photo-curable resin composition A.

Example °

0.4 part of benzoin methyl ether and 0.01 part of 2,6-di-tert-butyl-p-cresol are dissolved in 20 parts of oligoacrylate ("ARONIX M-7100" from Toagosei Chemical Industry Co.). Further 30 parts of a copolymer of methyl methacrylate and acrylonitrile, 20 parts of crystal quartz powder (grain size less than 20 jim) after a silane treatment and a low Amount of a dye added, and kneaded; it will

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a photo-curable resin mixture B obtained.

Ö-ütetest

Allow the resulting photocurable resin mixture to cure A and B using a high voltage mercury vapor lamp of 100 W (IM-102, UM-IOj? B from Ushio Electric Co.) measurements of the photo-curing rate, the flexural strength, the flexural modulus of elasticity, the compressibility, the Tensile strength, surface hardness and water absorbency carried out.

At 10 cm irradiation distance, the photocuring speed becomes measured based on the time required for the 2mm thick mixture to fully cure. The flexural strength, the flexural modulus of elasticity and the tensile strength are determined using a 3 × 10 × 60 mm sample of the cured Mixture using an Instron universal tester, point-to-point bending distance of 50 mm or pulling speed measured at 3 mm / min. The compressibility is measured using a tubular sample (6 mm diameter and 12 mm length) was measured using an Instron universal test device at a compression speed of 3 mm / min. The surface hardness is measured as Rockwell hardness on the 15 W scale. The water absorbency is determined according to the Measured by Japanese industry standard JIS T-6508. The results are listed in Table I.

For control purposes, Table I below the physical properties of a comparative sample are given, which are made of a conventional resin material for dental crowns has been produced in the usual coating technology.

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speed (seconds) Photohardenable
Resin mixture 20th B. 20th 29H537 114-0 Part I Flexural strength (kg / cm) A. 1250 94-0 205 Flexural modulus of elasticity
(kg / cm ² ) 15 χ 3 comparative
resin 82 Compressibility (kg / cm ^) 3600 A 0.7 Tensile strength (kg / ccr) 47O Surface hardness (HR) 90 780 laFasserabsorbable-
speed (mg / cm3) 0, 4-4- 4-
10 4-, 5 χ 10 2.2 x 10 1850 3OO 84- , 3 0,

For example, jacket crowns for the upper incisors are made by applying and shaping the above-described, photocurable resin mixture A and by only two exposure to actinic radiation from the above-described high-voltage mercury vapor lamp prepared for 30 seconds each. Mixture A is light deformable, and the jacket crowns obtained can easily be adapted to the tooth. Clinical conducted after a year Investigations show no significant abrasion or discoloration.

Further, frontal crowns for the upper incisors are made using the above-described photohardenable Resin mixture B and by irradiating only once with the aid of the high-voltage mercury vapor lamp during 30 seconds established. Mixture B shows good moldability, and the frontal crowns obtained can easily be adapted to the tooth to be treated. One year after the mission Clinical examinations performed on the frontal crowns show no significant abrasion and discoloration.

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15 parts of oligoacrylate ("ARONIX M-7100" Supra), 5 parts of oligoacrylate ("ARONIX M-715O"), 0.5 part of benzoin methyl ether and 0.01 part of 2,6-di-tert-butyl-p-cresol is mixed and used to form a Photohardenable resin mixture G dissolved. The obtained mixture C is in the liquid phase with a viscosity of about 8OGOcP at 25 ° C, and the photocuring rate is within 10 seconds. The crowns made of resin material coated with the photo-curable resin mixtures A and B thinly xiTorden are, show excellent shine.

Example 4-

20 parts of "ARONIX M-7IOO" (Supra), 0.7 parts of Benzil and 0.01 part of 2,6-di-tert-butyl-p-cresol v / earth mixed and kneaded with the addition of 20 parts of titanium oxide; a white, photo-curable resin mixture D is obtained.

The resulting mixture D is about 25 / in thickness to one 14K dental prosthetic alloy plate applied and with Irradiated with the help of a high-voltage mercury vapor lamp. The mixture is completely hardened within 15 seconds, and the frontal crowns have a natural color, the metallic color of the alloy plate being completely is covered.

Haitb arke it st e st

In each case 20 cm of the photocurable resin mixtures obtained according to Examples 1 to 4- are placed in a 50 cm container which is transparent to UV radiation. The resistance of these mixtures is determined by storage at 35 to 40 ⁰ G. Gelation and abnormal discoloration are also checked. The results are shown in Table II.

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Resin mixture A. - 15 - 2914537 1 It B. Table II Abnormal discoloration Il C. Storage time no 5 Il D. over 6 months Il Il 6 " II 6 " Il 'Il g

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Claims (12)

VOSSIUS ■ VOSSIUS · HiLTL · TAUCHNER · HEUNEMANN PATENT ADVOCATE SIEBERTSTRASSE 4 - 8O00 MÖNCHEN 86 · PHONE: (O89) 474O75 CABLE: BENZOL PATENT MÜNCHEN -TELEX 5-29 45 3 VOPAT O uZ: P O72 (He / H)
Case: PF 14-37 SAKKIiT INDUSTRY CO., LTD Osaka, Japan! "Process for the production of dental crowns made of plastic" Priority: April 11, 1978, Japan, No. 42889/78 Claims 1.J Process for the production of dental crowns from plastic or synthetic resin, characterized by the following process steps: a) Applying a photo-curable synthetic resin mixture on a plaster mold or on a metal frame a frontal crown, wherein the photohardenable synthetic resin mixture a polymerizable methacrylate and / or acrylate, a photosensitizer and / or a filler, and b) Curing of the synthetic resin mixture by uniform exposure to actinic radiation while maintaining it the shape of the tooth crown. 2. The method according to claim 1, characterized in that one or more compounds from the group of benzil and benzoin ethers is used as the photosensitizer.
35 909843 / 079S 3. The method according to claim 2, characterized in that the proportion of the photosensitizer based on the polymerizable Methacrylate and / or acrylate is 0.2 to 10 percent by weight. 4. The method according to any one of claims 1 to 3 »characterized in that that the filler in the photocurable synthetic resin is a water-soluble or a water-insoluble, having organic polymer. 5. The method according to claim 4, characterized in that the organic polymer has a proportion of 5 to 80 percent by weight based on the polymerizable methacrylate and / or acrylate.
15th 6. The method according to any one of claims 1 to 3 »characterized in that that the filler in the photocurable synthetic resin contains an inorganic polymer. 7. The method according to claim 6, characterized in that the inorganic polymer in the photocurable synthetic resin has a proportion of 20 to 85 percent by weight on the polymerizable methacrylate and / or acrylate Has.
25th 8. The method according to claim 6 or 7, characterized in that the inorganic filler is a silane treatment is subjected. 9. Method according to one of Claims 1 to 3, characterized in that that the filler is a water-soluble or insoluble, organic polymer and an inorganic polymer Contains polymer. 10. The method according to any one of claims 1 to 9, characterized in, that the photo-curable synthetic resin mixture 909843/0798 1 a peroxide as a catalyst and the photosensitizer contains. 11. The method according to claim 10, characterized in that 5 DiaCyl peroxide is used as the peroxide catalyst. 12..Verfahren according to claim 11, characterized in that 0.01 "to 2 percent by weight of dxacyl peroxide based on the polymerizable methacrylate and / or acrylate are used 10 become. 13 »Method according to one of claims 1 to 12, characterized in that that photocuring by exposure to actinic radiation with a wavelength of 15 at least 3400 A. 14, method according to claim 13 »characterized in that: with 2 mm thickness of the photo-curable synthetic resin, the curing by the actinic radiation within
20 60 seconds takes place. 909843/0798