DENTAL PROSTHESIS WITH A MULTIPART DESIGN, AND METHOD AND DEVICE FOR PRODUCING SAME

Abstract

The invention relates to a dental prosthesis comprising a first inner sub-region which has a first organically polymerized material and a second outer sub-region, which has a second organically polymerized material that is an organically modified and organically polymerized silicic acid (hetero)polycondensate. The first inner sub-region has a flexural strength of over 80 MPa according to DIN EN ISO 4049: 2009 and a lower elastic modulus than the second outer sub-region, while the second, outer sub-region has a flexural strength of at least 100 MPa according to DIN EN ISO 4049: 2009. The first organically polymerized material is preferably also an organically modified and organically polymerized material.

The dental prosthesis can be generated preferably using a mold system consisting of at least one first and a second negative mold, and the second negative mold is shaped so as to form a second cavity, Either both negative molds consist of at least two parts or the first negative mold is a single part and has an opening for the admission of light or IR radiation.

Claims

1. Dental prosthesis comprising a first, inner sub-region which has a first organically polymerized material and a second outer sub-region, which has a second organically polymerized material that is an organically modified and organically polymerized silicic acid (hetero)polycondensate, wherein the first inner sub-region has a flexural strength of over 80 MPa and a lower elastic modulus than the second outer sub-region, while the second outer sub-region has a flexural strength of at least 100 MPa.

2. Dental prosthesis according to claim 1, wherein the first organically polymerized material is polymerized using organically polymerizable groups which are copolymerizable with groups of the second organically polymerized material, and/or where the first organically polymerized material is a first organically modified and organically polymerized silicic acid (hetero)polycondensate.

3. Dental prosthesis according to claim 1, wherein the first, inner sub-region and/or the second outer sub-region each have a flexural strength of at least 130 MPa, where the flexural strength of the second outer sub-region may be greater than that of the first, inner sub-region.

4. Dental prosthesis according to claim 1, wherein the elastic modulus of the first, inner sub-region is at least 5.0 GPa and the elastic modulus of the second outer sub-region is at least 7.5 GPa.

5. Dental prosthesis according to claim 1, wherein the translucency of the first inner sub-region is smaller than the translucency of the second outer sub-region.

6. Dental prosthesis according to claim 1, wherein the organic polymerization of the first, inner sub-region and/or of the second outer sub-region was carried out at least partially via vinyl groups, preferably (meth)acrylic groups, and particularly preferably via methacrylate groups.

7. Dental prosthesis according to claim 1, wherein the first organically polymerized material is a first organically modified and organically polymerized silicic acid (hetero)polycondensate that is modified with phenyl group-containing organic residues and/or where the organically polymerized silicic acid (hetero)polycondensate of the second, outer sub-region is modified with phenyl group-containing organic residues.

8. Dental prosthesis according to claim 1, wherein the organically polymerized silicic acid (hetero)polycondensate of the second, outer sub-region is modified with organic residues having free hydroxy groups.

9. Dental prosthesis according to claim 1, wherein the first, inner sub-region and/or the second outer sub-region consists of a composite that has 15 to 55 wt.-%, preferably 20 to 50 wt.-% of organically polymerized silicic acid (hetero)polycondensate and 45 to 85 wt.-%, preferably 50 to 80 wt.-% of filler, or that has this composite in a proportion of preferably at least 75 wt.-%.

10. Dental prosthesis according to claim 9, wherein the filler consists of glass with an average primary particle size between 0.01 m and 5 m, preferably between 0.1 and 3.0 m.

11. Dental prosthesis according to claim 10, wherein the glass used as filler is silanized.

12. Dental prosthesis according to claim 1, wherein the first inner sub-region is provided with an adhesion promoter on its outer surface and/or has a roughened surface and/or the second outer sub-region is provided with an adhesion promoter on its inner surface.

13. Dental prosthesis according to claim 1, wherein the first inner sub-region has a protrusion that is suitable as locking pin or anchor.

14. Method for manufacturing a dental prosthesis according to claim 1, wherein (a) an organically polymerizable material as a precursor for the first, inner sub-region of the dental prosthesis is filled into a first negative mold and solidified therein, (b) the solidified first, inner sub-region in part of a second negative mold, which has a cavity with substantially the shape of the dental prosthesis, is provided with an organically polymerizable silicic acid (hetero)polycondensate as precursor for the second, outer sub-region, (c) the second negative mold is closed, (d) the second outer sub-region is solidified by heat curing, and (e) the dental prosthesis is taken out of the mold.

15. Method according to claim 14, wherein the first negative mold consists of two or more partial sub-regions (U-I/O-I), and is closed after the filling according to step (a), whereupon the first inner sub-region is solidified by heat curing.

16. Method according to claim 14, wherein the first negative mold (UI) remains open after filling according to step (a) and the first, inner sub-region is solidified by exposure to electromagnetic radiation, preferably by light or infrared radiation.

17. Method according to claim 14, wherein the solidified first, inner sub-region of the dental prosthesis is taken out of the first negative mold and transferred to the second negative mold.

18. Method according to claim 14, wherein the solidified first, inner sub-region of the dental prosthesis is left in a sub-region (U-I) of the first negative mold, whereby this part of the first negative mold together with another negative partial mold (O-II) forms the second negative mold.

19. Method according to one of claim 14, wherein the first negative mold has an additional cavity connected to the negative mold for the first, inner sub-region of the dental prosthesis, into which silicic acid (hetero)polycondensate that has not yet organically polymerized is filled in step (a) of the method, such that a locking or gripping pin is formed onto the first, inner sub-region.

20. Method according to claim 14, wherein the first inner sub-region is roughened and/or provided with an adhesion promoter after it has solidified and before it is provided with the second not yet polymerized (hetero)polycondensate.

21. Method according to claim 14, wherein during the solidification according to step (a) the first inner sub-region is not yet fully cured and its complete curing is performed together with step (d).

22. Mold system comprising at least a first and a second negative mold for the production of duromer-curing dental prostheses having an inner region and at least one further sub-region, wherein the inner region and the at least one additional sub-region of the dental prosthesis can be formed of materials with different properties, wherein the second negative mold (U-II/O-II;U-I/O-II;U-II/O-I;U-I/O-I) is configured such that it forms a second cavity having essentially the shape of the dental prosthesis, wherein (a) each negative mold consists of at least two parts (U/0), and (i) the first negative mold (U-I/O-I) is formed such that a first cavity is formed which has a smaller volume than the second cavity, and wherein the geometry of the first cavity is selected such is that the surface of an inner region of the dental prosthesis produced with the first negative mold can be completely or partially coated with an outer layer in the second negative mold or with the at least one additional sub-region of the dental prosthesis so that the finished dental prosthesis or the inner region and the at least one additional sub-region of the dental prosthesis is/can be formed, and/or (ii) the second negative mold consists of one of the parts of the first negative mold (U-I) and an additional part (O-II), or (b) the first negative mold (U-I) is a single part and has an opening for the admission of electromagnetic radiation such as light and the second negative mold consists of the first negative mold (U-I) or a first part of a second negative mold (U-II), each in combination with a second part (O-I), wherein the molds are designed such that together they form a cavity having a geometry that is selected such that the surface of an inner region formed with the first negative mold of the dental prosthesis can be coated completely or partially with an outer layer in the second negative mold so that the finished dental prosthesis is/are formed, wherein all of the named negative forms have a maximum of one or two openings after being assembled from the perspective parts through which excess resin and/or air can escape.

23. Mold system according to claim 22, characterized in that the mold system comprises at least one additional two-part negative mold with which an intermediate layer between the inner region and the outer layer can be produced.

24. Mold system according to claim 22, characterized in that the first cavity of the first negative mold (U-I) is connected to a second cavity in said first negative mold that enables the formation of a locking or gripping pin to the dental prosthesis.

25. Method for producing a duromer-curing dental prosthesis, in which a mold system according to claim 22 is used and the first negative mold is first filled with at least one first composite that is subsequently cured, and subsequently an inner region of the dental prosthesis thereby formed is introduced into at least one additional mold, which is then filled with the first or a second composite that is subsequently cured, so that the surface of the inner region is completely or at least substantially coated with the first or second composite.

26. Use of a dental prosthesis according to claim 1 as a CAD/CAM block for producing single- or multi-layer crowns, inlays, onlays or veneers, or as prefabricated single or multi-layer crowns, wherein the final finishing of the dental prosthesis is performed via a CAD/CAM process.

Description

[0072] In the following, the invention is explained in more detail with reference to specific exemplary embodiments.

A. MEASUREMENT METHODS

(1) Test Body Preparation and PerformanceVickers Hardness Test

[0073] The test body was prepared and tested according to the test standard DIN EN 843-4 [0074] The hardness was determined by preparing test discs 2 mm in height and with a diameter of 18 mm using a non-stick-coated stainless-steel mold [0075] A glass plate covered with PET film was used as an even surface [0076] Filling in the degassed resin/composite [0077] A glass plate covered with PET film was placed on top of the composite as an even surface [0078] After curing (as described in the Examples) the test bodies were removed from the molds [0079] Storage was at room temperature [0080] The test was performed with the hardness tester V-100-C1 from Leco [0081] The measurement was performed with a force of 1 kp for a holding time of 10 s.

(2) Test Body Preparation and PerformanceThree-Point Bending Test

[0082] The test body preparation and testing was carried out according to the test standard DIN EN ISO 4049: 2009 [0083] To determine the flexural strength and the elastic modulus, cuboid test rods with dimensions of 2 mm2 mm25 mm were prepared by means of non-stick metal molds [0084] Filling in the degassed resin/composite [0085] To prevent the formation of an oxygen inhibitor layer, the resin/composite that was filled into the mold was covered with a level layer of polyethylene terephthalate (PET) film [0086] After curing (as described in the Examples), the rods were removed from the molds and both side surfaces sanded using sandpaper with a grain size of 1200 for demolding, and stored as described in the Examples. [0087] Storage was at 40 C. for 24 hours for the thermally cured rods or 36 hours for the photocured rods [0088] The universal test machine Z100 from Zwick/Roell was used as the test device. [0089] The measurement was thereby performed with a standard force transducer of 100 N. The span length of the support rollers was 20 mm, their radius and that of the bending punch was 1 mm and the test speed 3 mm/min.

TABLE-US-00001 Overview of existing materials Natural dentin-enamel PMMA Glass ceramics Flexural strength n.d. 50-130 150-420 [MPa] Elastic modulus [GPa] 11-85 2.0-3.5 30-95

[0090] In contrast to natural dentin/enamel, PMMA demonstrated a very low elastic modulus, resulting in a high self-abrasion. Glass ceramics show very high values with respect to strength and the elastic modulus is in the range of natural dentin/enamel. A disadvantage of glass ceramics is the extensive processing and the deficits noted in the description.

TABLE-US-00002 Minimum requirements on the inventively employable resins/composites (in the cured state) Melting range Dentin range Flexural strength [MPa] >100 >80 Elastic modulus [GPa] >7.5 (preferably >11) >5

[0091] The strength and elastic modulus of the dentin core should have the minimum values shown in the table. As the outer layer, the enamel composite should, among other factors, achieve a high level of abrasion resistance with respect to strength/elastic modulus that are ideally in the range of natural dentin-enamel.

(3) Preparation of Test Specimens and PerformanceTranslucency Measurement

[0092] Round test discs 2 mm in height and with a diameter of 18 mm were prepared from the composites using stainless steel molds. PET films were used to obtain an airtight seal on the top and bottom sides of the composite, and glass plates used to provide smooth contact and coverage areas. The thermally curing composites were cured at 100 C. for 4 h in the oven and the light-curing composites for 100 s with a blue light emitter (wavelength of approximately 380-520 nm) from both sides at a distance of 0.5 cm, respectively. The translucency measurement was performed with a spectrophotometer Color i7 from X-Rite over a wavelength range of 360 to 750 nm.

B. PREPARATION OF TEST SPECIMENS AND ANTAGONISTS AND PERFORMANCE OF THE ABRASION TESTS

[0093] The wear behavior of composites was investigated using the chewing simulator CS-4.8 from SD Mechatronik. The specimens were embedded using sample holders of aluminum having a diameter of approximately 1.5 cm (see FIG. 3, which shows the sample holder before and after preparation of the composite). An excess of the corresponding composites was filled in the sample holder. The thermally curable composites were cured at 100 C. in the oven for 4 hours, the light-curable composite cured for 100 s with a blue light emitter (wavelength between approximately 380-520 nm) at a distance of 0.5 cm. The cured test specimens were stored for 24 hours at 23 C. and at a humidity of 40% until testing and prior to the measurement sanded flat using a sander with sending paper with a grain size of 4000 at 300 rpm.

[0094] For embedding the antagonists (abrading body), tapered antagonist holders of aluminum with a diameter of about 1.5 cm were used. Balls of Degussit, a high-density aluminum oxide ceramic, with a diameter of 5 mm were used as antagonists and fixed with PMMA. FIG. 4 shows such an antagonist holder of aluminum before and after preparation with the Degussit antagonist balls.

[0095] The sample holders prepared with material are mounted in the sample chambers and the prepared antagonist holders to the antagonist's punches.

[0096] The following test parameters were set on the device:

[0097] Load of samples during the test: 5 kg per sample

TABLE-US-00003 Up and downward stroke: 2 mm Up and downward speed: 60 mm/s Horizontal movement: 1 mm Horizontal speed: 40 mm/s Movement cycles: 300,000

[0098] The options time-optimized movement and minimum impulse on impact were activated.

[0099] The following settings were used for the thermocycling:

[0100] Temperatures of the rinse water: 5 and 55 C.

TABLE-US-00004 Rinsing time: 30 s Draining time of the water 11 s

C. EXAMPLES FOR THE PREPARATION OF THE RESINS AND COMPOSITES

C1. Resin Systems

C1A. Resin System A (Synthesis According to DE 44 16 857 C1)

[0101] Triphenylphosphine as catalyst, BHT (3,5-di-tert-butyl-4-hydroxytoluene) as stabilizer and then 47.35 g (0.550 mol) of methacrylic acid are added dropwise to 125.0 g (0.503 mol) 3-glycidyloxypropylmethyldiethoxysilane under a dry atmosphere and stirred at 80 C. (approximately 24 h). The conversion can be followed by the reduction of the carboxylic acid concentration by means of acid titration and the epoxide conversion by epoxide titration/NMR. After addition of ethyl acetate (1000 ml/mol silane) and H.sub.2O for hydrolysis with HCl as catalyst, the mixture is stirred at 30 C. The reaction is worked up after several days of stirring by shaking out with aqueous NaOH and water and filtrating through a hydrophobic filter. The mixture is first spun off and then drawn off under an oil pump vacuum. The result is a liquid resin with a viscosity of 3-5 Pa.Math.s at 25 C. and a refractive index n.sub.D1.477.

C1B. Resin System B (from DE 10 2014 115 751)

1st Step

Reaction Scheme:

[0102] ##STR00001##

(Proportion of educt: =0.6, =0.42):

[0103] 0.42 g triphenylphosphine as catalyst, 0.04 g BHT (2,6-di-tert-butyl-4-methyl phenol), 14.7 g (0.12 mol) of benzoic acid and then 7.23 g (0.084 mol) of methacrylic acid are added to 50.2 g (0.202 mol) 3-glycidyloxypropylmethyldiethoxysilane and stirred at 85 C. (approx. 24 h). The reaction can be followed as described in Example C1A. After addition of ethyl acetate (1000 ml/mol silane) and H.sub.2O for hydrolysis with HCl as catalyst, the mixture is stirred at 30 C. The course of hydrolysis is followed by water titration. The reaction is worked up after several days of stirring by shaking out with aqueous NaOH and water and filtrating through hydrophobic filter. The mixture is first spun off, and then drawn off under an oil pump vacuum. The result is a liquid resin without the use of reactive diluents (monomers) with a viscosity of about 19-26 Pa.Math.s at 25 C. and a refractive index n.sub.D1.506.

2nd Step

[0104] Note: the isocyanate group reacts not only with the hydroxy group of the 1st stage reaction products, but also with the vicinal hydroxy groups of the unreacted starting material if its cyclic ether groups were opened hydrolytically; a mixture of isomers results.

[0105] 6.52 g (0.042 mol) isocyanatoethyl methacrylate is added dropwise to 19.9 g (0.07 mol based on Si) of the 1st stage reaction mixture and optionally 0.026 g BHT under a dry atmosphere at 30 C. with stirring and further stirred at 30 C. The reaction can be followed via the reduction of the OCN band by IR spectrum. The band characteristic of the OCN group appears in the IR spectrum at 2272 cm.sup.1 The result is a liquid resin with a viscosity of approximately 102-128 Pa.Math.s at 25 C. and a refractive index n.sub.D1.504.

C1C. Resin System C (from WO 2015/018906 A1)

1st Step: Basic Reaction Principle:

[0106] ##STR00002##

(1=0.2):

[0107] 2.48 g (0.0123 mol) of diphenylphosphine oxide and 0.2 ml of 1,8-diazabicyclo[5.4.0] undec-7-ene (DBU) as catalyst are added to 16.0 g (0.0615 mol) of resin system A with stirring. The resulting reaction mixture is stirred at 50 C. until addition is completed. The reaction can, for example, be followed by NMR. After conventional work-up, e.g., in ethyl acetate (shaking out with water, filtrating through hydrophobic filter, spinning off and subsequent drawing off with an oil pump vacuum) a liquid resin results with a viscosity of approximately 37 Pas at 25 C. and a refractive index n.sub.D1.500.

2nd Step:

[0108] 17.2 g (0.4 mol) of methacrylic acid-isocyanatoethyl ester are added dropwise to 83.2 g of the product of step 1 (molar ratio=1:0.4) and optionally 0.043 g BHT (2,6-di-tert-butyl-4-methyl phenol) under a dry atmosphere at 30 C. with stirring, and stirring continued at 30 C. The conversion can be followed e.g., via the reduction of the OCN band by IR spectrum. The band characteristic of the OCN group appears at 2272 cm.sup.1 in the IR spectrum. The result is a liquid resin with a viscosity of approximately 98 Pa.Math.s at 25 C. and a refractive index n.sub.D of approximately 1.500. Further work-up is usually not required.

C1D. Resin System D (from WO 2015/018906 A1)

1st Step: (1st Variant: Ratio Resin System A:Thiophenol=1:0.4)

[0109] 6.61 g (0.079 mol) of thiophenol are added dropwise to 39.7 g (0.15 mol) of resin system A with stirring. The result is a liquid resin with a viscosity of approximately 7.0-7.2 Pas at 25 C. and a refractive index n.sub.D of approximately 1.506. Further workup is not required.

1st Step: (2nd Variant: Ratio Resin System A:Thiophenol=1:0.45)

[0110] 22.8 g (0.207 mol) of thiophenol are added dropwise to 121.4 (0.460 mol) of resin system A with stirring. The result is a liquid resin with a viscosity of approximately 6.9-7.0 Pas at 25 C. and a refractive index n.sub.D of approximately 1.508 (the slightly increased refractive index is due to the higher thiophenol proportion). Further workup is not required.

2nd Step:

Basic Reaction Principle:

[0111] ##STR00003##

(=0.8):

[0112] 1st variant: 6.21 g (0.04 mol) of methacrylic acid-isocyanatoethyl ester are added dropwise to 15.4 g of first stage product, 1st variant (0.05 mol) and 0.043 g BHT (2,6-di-tert-butyl-4-methyl phenol) under a dry atmosphere at 30 C. with stirring and stirring continued at 30 C. The conversion can e.g., be tracked via the reduction of the OCN band by IR spectrum. The band characteristic of the OCN group appears in the IR spectrum at 2272 cm.sup.1. The result is a liquid resin with a viscosity of approximately 36 Pa.Math.s at 25 C. and a refractive index n.sub.D of approximately 1.502. Further workup is not required.

[0113] 2nd variant: 54.6 g (0.352 mol) of methacrylic acid-isocyanatoethyl ester are added dropwise to 138 g of first stage product, 2.sup.nd variant (0.440 mol) and 0.096 g BHT (2,6-di-tert-butyl-4-methyl phenol) under a dry atmosphere at 30 C. with stirring and stirring continued at 30 C. The band characteristic of the OCN group appears in the IR spectrum at 2272 cm.sup.1. The result is a liquid resin with a viscosity of approximately 43 Pa.Math.s at 25 C. and a refractive index n.sub.D of approximately 1.506. Further workup is not required.

C1E. Resin System E (from DE 103 49877.8)

Basic Reaction Principle:

[0114] ##STR00004##

(Proportion of educt: =0.7):

[0115] 54.3 g of methacrylic acid-isocyanatoethyl ester (0.70 mol) are added dropwise to 130.3 g (0.50 mol) of the resin system A and 0.09 g BHT under a dry atmosphere at 30 C. with stirring and stirring continued at 30 C. After complete conversion, a liquid resin results with a viscosity of approximately 22-28 Pas at 25 C.

C2: Composite and their Properties in the Cured State

[0116] The components given below are mixed, placed in molds, and cured using the indicated measures. The measurement of properties was performed by the determination methods above

C2A. Composites for the Dentin Core

Example C2A-a

[0117] 50 wt.-% resin system B+2 wt.-% DBPO

[0118] 50 wt.-% filler proportion, silanized (Schott GM32087 glass), consisting of 100 wt.-% Ultrafine, primary particle size: 0.4 m (3 passages in the three-roll mill)

[0119] Thermal curing for 4 hours at 100 C., 1 d dry storage at 40 C.

[0120] Breaking strength: 1369 MPa

[0121] Elastic modulus: 5.30.2 GPa

[0122] Translucency: 56%

Example C2A-b

[0123] 40 wt.-% resin system B+2 wt.-% DBPO

[0124] 60 wt.-% filler proportion, silanized (Schott GM27884 glass), consisting of 100 wt.-% Ultrafine, primary particle size: 0.7 m (3 passages in the three-roll mill)

[0125] Thermal curing for 4 hours at 100 C., 1 d dry storage at 40 C.

[0126] Breaking strength: 1606 MPa

[0127] Elastic modulus: 6.80.3 GPa

[0128] Translucency: 68%

Example C2A-c

[0129] 40 wt.-% resin system B+2 wt.-% DBPO

[0130] 60 wt.-% filler proportion, silanized (Schott GM27884 glass), consisting of [0131] 67 wt.-% Ultrafine, primary particle size: 0.4 m (3 passages in the three-roll mill) [0132] 33 wt.-% Ultrafine, primary particle size: 0.7 m (4 passages in the three-roll mill)

[0133] Thermal curing for 4 hours at 100 C., 1 d dry storage at 40 C.

[0134] Breaking strength: 1595 MPa

[0135] Elastic modulus: 6.50.3 GPa

[0136] Translucency: 61%

Example C2A-d

[0137] 27 wt.-% resin system C+2 wt.-% DBPO

[0138] 73 wt.-% filler proportion, silanized (Schott GM27884 glass), consisting of [0139] 18 wt.-% Ultrafine, primary particle size: 0.18 m (3 passages in the three-roll mill) [0140] 14 wt.-% Ultrafine, primary particle size: 0.4 m (3 passages in the three-roll mill) [0141] 68 wt.-% Standard Grind K6, primary particle size: 3 m (6 passages in the three-roll mill)

[0142] Thermal curing for 4 hours at 100 C., 1 d dry storage at 40 C.

[0143] Breaking strength: 17113 MPa

[0144] Elastic modulus: 10.60.1 GPa

[0145] Hardness: 81 HV

[0146] Translucency: 25%

Example C2A-e

[0147] 40 wt.-% resin system D (2nd variant)+1 wt.-% LTPO

[0148] 60 wt.-% filler proportion, silanized (Schott GM27884 glass), consisting of [0149] 60 wt.-% Ultrafine, primary particle size: 0.4 m (2 passages in the three-roll mill) [0150] 40 wt.-% Ultrafine, primary particle size: 0.7 m (3 passages in the three-roll mill)

[0151] Light hardening for 2100 s, 1.5 d dry storage at 40 C.

[0152] Breaking strength: 1586 MPa

[0153] Elastic modulus: 6.30.223 GPa

[0154] Translucency: 62%

[0155] Hardness: 41 HV 1/10

Example C2A-f

[0156] 40 wt.-% resin system D (2.sup.nd variant)+1 wt.-% LTPO

[0157] 60 wt.-% filler proportion, silanized (Schott GM32087 glass), consisting of [0158] 40 wt.-% Ultrafine, primary particle size: 0.4 m (2 passages in the three-roll mill) [0159] 60 wt.-% Ultrafine, primary particle size: 5 m (5 planetary mixture)

[0160] Light hardening for 2100 s, 1.5 d dry storage at 40 C.

[0161] Breaking strength: 15410 MPa

[0162] Elastic modulus: 10.70.334 GPa

[0163] Translucency: 37%

[0164] Abrasion: 1.49 mm.sup.3 volume wear

[0165] Hardness: 78 HV 1/10

Example C2A-g

[0166] 50 wt.-% resin system D (2.sup.nd variant)+1 wt.-% LTPO

[0167] 50 wt.-% filler proportion, silanized (Schott GM27884 glass), consisting of [0168] 100 wt.-% Ultrafine, primary particle size: 0.7 m (2 passages in the three-roll mill)

[0169] Light hardening for 2100 s, 1.5 d dry storage at 40 C.

[0170] Breaking strength: 15016 MPa

[0171] Elastic modulus: 5.50.370 GPa

[0172] Translucency: 75%

[0173] Hardness: 35 HV 1/10

C2B. Composite for the Enamel Layer

Example C2B-a

[0174] 50 wt.-% resin system A+2 wt.-% DBPO

[0175] 50 wt.-% filler proportion, silanized (Kstrosol 3550), consisting of 100 wt.-% of nanoparticles, primary particle size: 0.1 m

[0176] Thermal curing for 4 hours at 100 C., 1 d dry storage at 40 C.

[0177] Breaking strength: 1118 MPa

[0178] Elastic modulus: 4.40.1 GPa

[0179] Translucency: 73%

Example C2B-b

[0180] 30 wt.-% resin system A+2 wt.-% DBPO

[0181] 70 wt.-% filler proportion, silanized (Kstrosol 3550 and Schott G018-307 glass), consisting of [0182] 25 wt.-% of nanoparticles, primary particle size: 0.1 m [0183] 75 wt.-% Ultrafine, primary particle size: 0.7 m (4 passages in the three-roll mill)

[0184] Thermal curing for 4 hours at 100 C., 1 d dry storage at 40 C.

[0185] Breaking strength: 16513 MPa

[0186] Elastic modulus: 8.70.4 GPa

[0187] Translucency: 29%

Example C2B-c

[0188] 35 wt.-% resin system A+2 wt.-% DBPO

[0189] 65 wt.-% filler proportion, silanized (Schott G018-307 glass), consisting of 100 wt.-% Ultrafine, primary particle size: 0.7 m (4 passages in the three-roll mill)

[0190] Thermal curing for 4 hours at 100 C., 1 d dry storage at 40 C.

[0191] Breaking strength: 15511 MPa

[0192] Elastic modulus: 7.70.3 GPa

[0193] Translucency: 66%

Example C2B-d

[0194] 30 wt.-% resin system A+2 wt.-% DBPO

[0195] 70 wt.-% filler proportion, silanized (Kstrosol 3550 and Schott G018-307 glass), consisting of [0196] 25 wt.-% of nanoparticles, primary particle size: 0.1 m [0197] 25 wt.-% Ultrafine, primary particle size: 0.4 m (3 passages in the three-roll mill) [0198] 50 wt.-% Ultrafine, primary particle size: 0.7 m (4 passages in the three-roll mill)

[0199] Thermal curing for 4 hours at 100 C., 1 d dry storage at 40 C.

[0200] Breaking strength: 15511 MPa

[0201] Elastic modulus: 8.10.6 GPa

[0202] Translucency: 28%

Example C2B-e

[0203] 20 wt.-% resin system A+2 wt.-% DBPO

[0204] 80 wt.-% filler, silanized (Kstrosol 3550 and Schott G018-307 glass), consisting of [0205] 25 wt.-% of nanoparticles, primary particle size: 0.1 m [0206] 25 wt.-% Ultrafine, primary particle size: 0.7 m (4 passages in the three-roll mill) [0207] 50 wt.-% Standard Grind K5, primary particle size: 5 m (4 passages in the three-roll mill)

[0208] Thermal curing for 4 hours at 100 C., 1 d dry storage at 40 C.

[0209] Breaking strength: 1697 MPa

[0210] Elastic modulus: 130.5 GPa

[0211] Hardness: 91 HV

[0212] Translucency: 22%

[0213] Abrasion: 0.47 mm.sup.3 (300000 cycles, 5 kg load)

Example C2B-f

[0214] 30 wt.-% resin system D+1 wt.-% Lucirin-TPO

[0215] 70 wt.-% filler proportion, silanized (Schott GM27884 glass), consisting of [0216] 33 wt.-% Ultrafine, primary particle size: 0.7 m (3 passages in the three-roll mill) [0217] 67 wt.-% Standard Grind K6, primary particle size: 3 m (315 min in planetary mixer, 40 rpm)

[0218] Light-initiated curing 100 s on both sides, 1.5 d dry storage at 40 C.

[0219] Breaking strength: 15111 MPa

[0220] Elastic modulus: 7.90.3 GPa

[0221] Translucency: 61%

Example C2B-g

[0222] 24 wt.-% resin system E+2 wt.-% DBPO

[0223] 76 wt.-% filler proportion, silanized (Kstrosol 3550)+silanized Schott G018-307 glass consisting of: [0224] 14 wt.-% nanoparticles, primary particle size: 0.08 m [0225] 36 wt.-% GM27884, primary particle size: 0.4 m (2 passages in the three-roll mill) [0226] 50 wt.-% GM27884, primary particle size: 5 m (5 passages in the three-roll mill)

[0227] Thermal curing for 4 h at 100 C., 1 d dry storage at 40 C.

[0228] Breaking strength: 1596 MPa

[0229] Elastic modulus: 13.00.517 GPa

[0230] Translucency: 22%

[0231] Abrasion: 0.53 mm.sup.3 (300000 cycles, 5 kg load)

[0232] Hardness: 101 HV 1/10

Example C2B-h

[0233] 24 wt.-% resin system E+2 wt.-% DBPO

[0234] 76 wt.-% filler proportion, silanized Schott G018-307 glass consisting of: [0235] 14 wt.-% G018-307, primary particle size: 0.4 m (2 passages in the three-roll mill) [0236] 36 wt.-% G018-307, primary particle size: 0.7 m (2 passages in the three-roll mill) [0237] 50 wt.-% G018-307, primary particle size: 5 m (5 passages in the planetary mixer)

[0238] Thermal curing for 4 h at 100 C., 1 d dry storage at 40 C.

[0239] Breaking strength: 1486 MPa

[0240] Elastic modulus: 11.70.735 GPa

[0241] Translucency: 38%

[0242] Abrasion: 0.85 mm.sup.3 volume wear

[0243] Hardness: 100 HV 1/10

Example C2B-i

[0244] 40 wt.-% resin system E+2 wt.-% DBPO

[0245] 60 wt.-% filler proportion, silanized (Kstrosol 3550)+silanized Schott G018-307 glass consisting of: [0246] 29 wt.-% nanoparticles, primary particle size: 0.08 m [0247] 71 wt.-% GM27884, primary particle size: 0.4 m (3 passages in the three-roll mill)

[0248] Thermal curing for 4 h at 100 C., 1 d dry storage at 40 C.

[0249] Breaking strength: 15110 MPa

[0250] Elastic modulus: 7.80.336 GPa

[0251] Translucency: 31%

[0252] Abrasion: 0.38 mm.sup.3 (300000 cycles, 5 kg load)

[0253] Hardness: 69 HV 1/10

Example C2B-j

[0254] 40 wt.-% resin system E+2 wt.-% DBPO

[0255] 60 wt.-% filler proportion, silanized Schott G018-307 glass consisting of: [0256] 29 wt.-% GM27884, primary particle size: 0.4 m (2 passages in the three-roll mill) [0257] 71 wt.-% GM27884, primary particle size: 0.7 m (3 passages in the three-roll mill)

[0258] Thermal curing for 4 h at 100 C., 1 d dry storage at 40 C.

[0259] Breaking strength: 1598 MPa

[0260] Elastic modulus: 7.40.224 GPa

[0261] Translucency: 60%

[0262] Abrasion: 0.71 mm.sup.3 (300000 cycles, 5 kg load)

[0263] Hardness: 70 HV 1/10

Example C2B-k

[0264] 27 wt.-% resin system C+2 wt.-% DBPO

[0265] 73 wt.-% filler proportion, silanized (Schott GM27884 glass) consisting of: [0266] 18 wt.-% Ultrafine, primary particle size: 0.18 m (3 passages in the three-roll mill) [0267] 14 wt.-% Ultrafine, primary particle size: 0.4 m (3 passages in the three-roll mill) [0268] 68 wt.-% Standard Grind K6, primary particle size: 3 m (6 passages in the three-roll mill)

[0269] Thermal curing for 4 h at 100 C., 1 d dry storage at 40 C.

[0270] Breaking strength: 17113 MPa

[0271] Elastic modulus: 10.60.1 GPa

[0272] Hardness: 81 HV 1/10

[0273] Translucency: 25%

D. EXAMPLES FOR THE PRODUCTION OF MULTI-LAYER PROSTHETIC TEETH

Example D1

[0274] The moldings parts are coated with a non-stick coating and for better flow behavior of the composite brought to a temperature of 45 C. First, the bottom mold- and top mold of the dentin mold are filled with dentin composite (see FIG. 2), which is also preheated to 45 C., using a syringe. Then, the top mold is placed onto the bottom mold part, the mold is closed and the composite cured at 100 C. in the oven for 4 h (suitable for the Denton composite with DBPO as initiator in the specific case; may be optionally changed). After the mold is opened, the polymerized dentin core is pushed out from below using the locking pin, sandblasted to achieve mechanical retention, and then inserted into the bottom part U-II, which together with the top part O-II represents the negative mold of the final tooth plus enamel region. The composite for the enamel layer that was kept at a temperature of 45 C. is filled into the top and bottom mold parts using a syringe. A small round opening in the top part serves as a drain for excess material. The curing process and the removal of the prosthetic tooth correspond to the procedure for the dentin. Lastly, after removing the prosthetic tooth from the mold, the pin is detached from the bottom of the tooth.

Example D2

[0275] To produce the two-layer prosthetic teeth, two-part molds are used that have the contour of the negative mold for the dentin core (bottom part U-I and top part O-I) or after exchanging the mold top O-I with O-II, have the enamel layer and thus the entire prosthetic tooth (bottom part U-I and top part O-II). These negative molds are slightly tapered towards the top, in order to facilitate removal of the tooth prosthesis after polymerization. In contrast to the molds of Example D1, these molds do not have a cavity for the formation of a locking pin. They are shown in FIG. 5; there an embodiment is shown with which a plurality of teeth can be produced. Of course, this molding system variant can also be realized with only one cavity for the production of a tooth or tooth part.

[0276] The molding parts are coated with non-stick coating and heated at 45 C. to achieve a better flow behavior of the composite. First, the bottom mold- and top mold of the dentin mold are each with dentin composite, which is also pre-heated to 45 C., using a syringe. Then, the top mold is placed onto the bottom mold part, the mold is closed and the composite cured at 100 C. in the oven for four hours. After the mold is opened, the region of the polymerized dentin core that projects from the mold and onto which the composite for the enamel layer is then coated, and which is at a temperature of 45 C., is sandblasted to achieve mechanical retention. The mold is closed with the second top mold part O-II, which represents the negative mold of the final tooth including enamel region, whereby a small circular opening in the top serves as a drain for excess material. After curing at 100 C. in oven for four hours, the prosthetic tooth is removed from the mold.

Example D3

[0277] To prepare the two-layer denture teeth, a single mold (bottom part U-I) is used in a first step (see FIG. 6), which has the contour of the negative mold of the dentin core. For the subsequent buildup of the enamel layer or of the entire prosthetic tooth, a two-part mold (bottom part U-II and top part O-I) is used. The negative molds are slightly tapered towards the top, in order to facilitate the removal of the dentin core or the prosthetic tooth after polymerization. In addition, the mold sections (U-I and U-II) have a round opening with a diameter of about 3 mm in the center and over the entire height to the bottom part (basal side) of the later tooth, which serves as a locking and catch pin.

[0278] The molding parts are coated with non-stick coating and heated at 45 C. to achieve a better flow behavior of the composite. First, the bottom mold of the dentin mold (U-I) is filled with dentin composite, which is also pre-heated to 45 C., using a syringe and thermally cured at 100 C. in an oven for four hours by blue light emitters (e.g., for 100 s) or IR emitters. The infrared emitter (IR emitter) is at a distance of 7 cm from the filled mold. The IR power and the effective duration of the irradiation can be varied. A maximum power is set for the composites to ensure the necessary decomposition temperatures for the respective thermal initiators or to exclude material damage. This can, for example, be 200 watts. The polymerized dentin core is pushed out from below using the locking pin, sandblasted to achieve mechanical retention, and then inserted into the bottom part of U-II, which together with the top part O-II represents the negative mold of the final tooth, including the enamel region. The composite at a temperature of 45 C. for the enamel layer is filled using a syringe into both the top mold and bottom mold and the mold is then closed. A small round opening in the top part serves as a drain for excess material. After curing the composite at 100 C. in the oven for four hours, after opening of the mold the polymerized prosthetic tooth is pushed out from below via the locking pin and the pin detached from the bottom of the tooth.

E. CURED PROSTHETIC TEETH

E1

[0279] The method for the preparation of prosthetic teeth was performed with the dentin composite C2A-c and the enamel composite C2B-e according to the method D1. The results of the compression tests on the prosthetic teeth constructed from these composites showed that at 3.1 kN they withstand a several-fold larger force than the human bite force of 0.14 to 0.73 kN reported in the literature.

E2

[0280] The method for the preparation of prosthetic teeth was performed with the dentin composite C2A-e and the enamel composite C2B-g according to the method D3 (light-curing for dentin composite+thermal curing for the enamel composites). The results of the compression tests on the prosthetic teeth constructed from these composites showed that at 3.70.4 kN they withstand a several-fold larger force than the human bite force of 0.14 to 0.73 kN reported in the literature.

[0281] Both methods E1. and E2., together with the high compression until fracture and the flexibility thereby shown, speak for a highly successful production and functionality of the two-layer prosthetic teeth.