SE519990C2 - Powdered material for use in manufacture of ceramic material for dental purposes has composition and/or structure suitable for giving ceramic material translucence in hydrated state - Google Patents

Abstract

Powdered material has a composition and/or structure suitable for giving ceramic material translucence in the hydrated state. It has a binder phase consisting of a cement-based system, and has the capacity, following saturation with a liquid reacting with the binder phase, to hydrate to a chemically bonded ceramic material, preferably for dental purposes.

Description

15 20 25 30 35 519 990 2 P1621 .Mt r. Hydration fluid before application of the material or in situ in a cavity, e.g. a dental cavity.

Later it was shown in SE 502 987 that for cement systems complete hydration (which was then considered to reduce the risk of dimensional changes) can take place if complete soaking and subsequent compaction of the cement system takes place with the help of a specially designed stopper. Again later it has been shown in SE 514 686 that a cement system of the type referred to in SE 463 493 or SE 502 987 can be made to exhibit dimensionally stable long-term properties when the material comprises one or more expansion compensating additives.

Materials manufactured in accordance with SE 463 493, SE 502 987 or SE 514 686 have certainly been shown to meet the krav most requirements which, as stated above, can be imposed on dental filling materials.

However, it has been shown that the aesthetics of the material suffer, despite tooth color, because the material is opaque, which means that the material does not have sufficient optical properties to look natural. Natural tooth transmits light, especially enamel. The way in which light is diffused through the tooth is described as translucent, which must be distinguished from transparent. A definition of a translucent material reads: “A material that reflects, transmits and absorbs light. Objects cannot be clearly seen through the material when the material is placed between the object and the observer "(Lemire, Burk, Color in dentistry, J. M. Ney Company (l975))". One way to measure translucency is to determine the ratio between the amount of reflected light with a white background and with a black background (ISO 9917). A material is described as translucent if it has an opacity between 35 and 90%, opaque above 90% and transparent below 35%. Natural dentin has an opacity of about 70% while natural enamel has an opacity of about 35%. The ability of a dental filling material to mimic the appearance of the natural tooth is largely dependent on the material being translucent.

In the abstract to JP 57209871 it is mentioned that translucency can be achieved in a material of Portland cement and water glass.

JP 51111828 describes a method for producing 3CaOIAl2O306H2O. In the method, the raw materials for the binder phase are already mixed with an excess of water for 1-20 hours and light heating, from room temperature to 100 ° C. It is stated that hydrated calcium aluminate is formed in the form of 3CaOOAl2O306H2O. This hydrated calcium aluminate is heated to between room temperature and 100 ° C and pressed simultaneously at 519 990 f; d P162l together at 50-800 MPa for 10-60 minutes, possibly after adding additional water, to a ceramic which is then dried at 60-250 ° C without drifting sticky water. Thus, in the method described in JP 51111828, the mechanical compression of already hydrated material is performed. However, it is claimed that the ceramic formed exhibits translucency.

A related problem is to achieve radioopacity at the same time as translucency, which is required of a dental filling material in order for it to be clearly distinguishable from natural tooth and caries attack, respectively, by X-ray. The problem is due to the fact that the X-ray contrast agents that are common today, e.g. ZrOQ and SnOg, interferes with translucency. Another problem is to achieve other optical effects (lurniniscence) of the material at the same time as translucency and radioopacity, which optical effects are similar to optical effects in natural tooth. A natural tooth fl uoresces e.g. when lighting in light that contains UV light, e.g. daylight. Fluorescence means that a material exhibits the ability to absorb light of a short wavelength (high energy) and then emit light of another, longer wavelength (lower energy). This property gives the tooth life and is experienced as whiter in daylight than in room lighting (which does not contain UV). According to Monsénégo, Burdairon, Clerjaud, Fluorescence of dental porcelain, The journal of prosthetic dentistry, Vol. 69, no. 1, Jan 1993, natural tooth has its emission maximum at a light wavelength of 450 nm, which corresponds to blue light.

Fluorescence in combination with translucency in teeth makes the ores uorescent light appear to come from inside the material. It is desirable for a material scarred for dental fillings to combine translucency and uorescence in order for it to be experienced as a natural tooth. As I said, it is also desirable that these properties are combined with the ability to provide X-ray contrast as this is used to check the quality of the repair. Also other optical effects such as e.g. luster of the material and so-called opal effect, ie simulated translucence, can be desirable to achieve the desired aesthetics of a dental filling material which consists of a chemically bonded ceramic material whose bonding phase consists mainly of a cement-based system.

DESCRIPTION OF THE INVENTION An object of the present invention is to provide a ceramic material of the type indicated in the introduction, which material exhibits translucency. Preferably, the material should at the same time exhibit radioopacity as well as possibly also other optical properties that mimic the appearance of natural tooth, e.g. fl uorescence, luster and / or opal effect. The invention also aims to provide a powder material which has the ability to hydrate after soaking with a binder phase reacting liquid to a chemically bonded ceramic material of the type intended according to the invention.

In the following description, the term “material” refers to both the powder material and the chemically bonded ceramic material, unless otherwise specified.

The term binder phase refers to a cement component in the material, regardless of whether it is the powder material or the hydrated ceramic product.

The desired and other properties are achieved according to the invention in that the material has a composition and / or structure suitable for giving the ceramic material translucence, in a hydrated state.

According to one aspect of the invention, the binder phase is optimized for translucency of the ceramic material, preferably in terms of physical or chemical properties of the binder phase. Alternatively, the material is optimized for translucency of the ceramic material in the form of properties of one or more of the additives suitable to give the core material translucency.

According to another aspect of the invention, the ceramic material exhibits a translucency corresponding to 35-90%, preferably 40-85% and even more preferably 50-80% opacity, in a hydrated state.

According to another aspect of the invention, it is preferred that the material comprises an additive which is adapted to impart radioopacity to the ceramic material, while simultaneously maintaining or increasing the translucency of the ceramic material.

According to another aspect of the invention, the material has a composition and / or structure which is also suitable for giving the ceramic material other optical effects which mimic optical effects of natural tooth, which optical effects are constituted by any effect in the group consisting of fl uorescence, luster, opalescence, iridescence and opalescence.

The powder material must furthermore meet the above requirements for formability and durability, and be easy to handle in connection with its wetting and application in the cavity, e.g. a dental cavity. The ceramic material formed should furthermore, for dental applications, meet the requirements imposed on such materials as described above. It is particularly preferred that the powder material is in the form of a crude body having a compact of 55-67% by volume of solid phase, preferably 57-63% by volume of solid phase and even more preferably 58-61% by volume of solid phase, before hydration. , in the manner described in SE 463 493. However, the invention is also fully applicable in connection with a wet-formed material which is in loose powder form before hydration, such as the powder material described in SE 502 987. The material may also comprise one or more expansion compensating additives suitable for giving the ceramic material dimensionally stable long-term properties, as described in SE 514 686. In this case, it generally applies that said binder phase consists at least mainly of calcium aluminate cement. However, the addition of another or other cement binder phases in total contents of less than 30% by volume can be used, preferably 1-20% by volume and even more preferably 1-10% by volume. Additives of ordinary Portland cement (OPC cement) or crystalline silica are advantageously used. Furthermore, it is desirable that the ceramic material have a hardness of at least 50 HV, in a hydrated state, preferably at least 100 HV and even more preferably 120-300 HV.

DETAILED DESCRIPTION OF THE INVENTION In the following, various aspects which aim to achieve translucency, radioopacity, uorescence or other optical properties of a ceramic material of the type mentioned in the introduction will be described in greater detail.

Whiteness of the binder phase For calcium aluminate cement, the translucency can be improved by using powder raw material for the binder phase, ie the calcium aluminates, which have a whiteness value above 70, preferably above 74 according to ASTM E313. In white raw materials, the absorption of light is low, which contributes to improved translucency. Especially transition metals (in metal or oxide form) give a grayer or colored powder, which is thus not desirable. Therefore, it is preferred that the content of transition metals in the powder mixture is below 0.6% by weight, preferably below 0.5% by weight. However, small contents of oxides of transition metals can be used to color the material to resemble natural tooth color.

Especially iron oxides can be used for this purpose, but then in contents of less than 0.5% by weight, preferably less than 0.3% by weight.

Refractive index Refractive index in visible light of additives in the material also affects the translucency.

It is preferred that the refractive index of the additives be as similar to the refractive index of the binder phase in the hydrated state as possible. For this purpose, additives (filer) can be used P162l only for the purpose of improving translucency. However, it is also possible to achieve radioopacity with only slightly reduced, maintained or improved translucency, by utilizing additives which provide radioopacity, but which have a refractive index which is close to the refractive index of the binder phase in a hydrated state. 1.6 is given below as the refractive index of the calcium aluminate, which is an average of the phases 3CaOOAl2O3 ~ 6H2O (1.63) and Al2O3O3HZO (1.57) which are the final phases of the hydrated binder phase. It is preferred that the refractive index of the additive does not deviate more than 15% from the refractive index of the hydrated binder phase, preferably not more than 10% and even more preferably not more than 5%.

In order to obtain radioopacity, the additive must also contain an atom type with a density above 5 g / cms (calculated on pure element), ie heavy metals from V and up in the periodic table, preferably Ba, Sr, Zr, La, Eu, Ta and / or Zn. An advantage of using an additive that includes barium and / or strontium is that since barium and strontium are in the same atomic group as calcium, barium and / or strontium can enter the binding phase and replace calcium in certain places.

In general, this is a desire, ie the use of additives that interact with the binder phase and / or go into solid solution therein.

It is preferred that the additive be a glass, i.e. amorphous phase, most preferably a silicate glass. It is also preferred that the additive also contain fl uor.

Examples of additives which meet one or more of the stated requirements are: silicate glass, barium aluminum-borosilicate glass, barium aluminum florosilicate glass, barium sulphate, barium floride, zirconium-zinc-strontium-borosilicate glass, apatite, fl uorapatite and similar materials. In these materials, barium can be replaced by strontium and the materials can also contain fl uor. The additive materials may further exhibit any morphology or shape, including: spheres, regular or irregular shapes, whiskers, plates or the like. Particles of the additive material should be less than 50 μm, preferably less than 20 μm and even more preferably less than 10 μm.

The size of the particles is measured by laser diffraction and is calculated as the volume average value D [4,3].

The additives of this type may be present in total amounts of at least 3% by volume, preferably at least 5% by volume and even more preferably at least 10% by volume, but not more than 55% by volume, preferably not more than 50% by volume and even more preferably at most 45% by volume, in the powder material. 1019 20 25 30 35 519 990 Pl62l Porosity The translucency can be improved by a low porosity level in the finished ceramic material, preferably a porosity level below 20%, even more preferably below 10% and even more preferably below 5%. This is also due to phenomena that have to do with the refractive index. In the mouth, the pores are filled with saliva / water, which has a refractive index of 1.33. Thus - the smaller the porosity, the smaller the amount of saliva / water that deviates in refractive index compared to the binder phase. The size of the pores should be less than 5 μm, preferably less than 1 μm and even more preferably less than 300 nm.

The porosity can be affected by grinding the powdered binder phase and controlling the mechanical pressure in the manufacture of the hydrated material. When manufacturing a raw press body, e.g. the mechanical pressure should preferably be 40 - 300 MPa and even more preferably 70 - 250 MPa and the degree of compactness achieved thereby should be as stated above for raw compacts. When manufacturing in the form of slurry of dissolved powdery material in the liquid reagent, an initial pre-drainage is preferably carried out at a pressure of less than 10 MPa, to a compact degree of 35-50% by volume of solid phase. Then final compaction is carried out under a pressure of at least 20 MPa, preferably at least 30 MPa, even more preferably at least 50 MPa and up to 300 MPa, to a final compact degree of 47-70% by volume solid phase, preferably> 51% by volume solid phase and even more preferably> 55% by volume solid phase. When made from a granular powder material, a compression molding is carried out at a pressure of preferably 40-300 MPa, even more preferably 70-250 MPa, to a final compact degree of 47-70% by volume solid phase, preferably> 51% by volume solid phase and even more preferably> 55% by volume solid phase.

Particle size The particle size of phases included in the material, especially of the binder phase, is important because the light is scattered within the grain boundaries. The particle size should therefore be optimized with regard to strength and light scattering. Particle sizes below 80 microns, preferably below 20 microns and even more preferably below 15 microns are preferred. The particle size is measured by laser diffraction and the volume-weighted average value is given (also called D [4,3]).

In addition, the translucency can be further improved if the amount of particles of the same size as the wavelength of visible light, ie 300 - 800 nm, is minimized. It is then preferred with particle sizes in the material above 3 μm, preferably above 2 μm and even more preferably above 1 μm and / or particle sizes below 300 nm, preferably below 519 990 8 P1921 200 nr. This can e.g. is achieved by sieving the powdered binder phase.

Sifting can take place through a number of different techniques that are known per se, e.g. wind screening or wet screening with canvas.

Phase composition By controlling the composition of the binder phase, the number of phases in the final product can be minimized, leading to reduced opacity. This is because the light refraction decreases e fi because the difference in refractive index between grains of the same phase is zero.

Particularly preferred is a mixture of the phases 3CaOOAl2O3 and CaOøAl2O3 in the powder material with a simultaneous minimization of CaOO2Al2O3. This leads to the amount of Al2O3 ~ 3H2O in the final product being minimized or completely excluded, whereby instead only 3CaO ~ Al2O306H2O is formed by the binder phase. According to one aspect of the invention, the binder phase of the powder material is at least 70% by weight, preferably at least 80% by weight and even more preferably at least 90% by weight of CaO 2 AlgO

By using in this way essentially only CaO : 10.

Surface The surface of the ceramic material, in a hydrated state and after any final treatment of the material, can also affect the translucency. Preferably, the surface has a surface unit, measured as R., which is lower than 10 μm, preferably lower than 2 μm and even more preferably lower than 1 μm. This can be achieved by sanding / polishing the surface with a sufficient sanding / polishing part or sanding / polishing tool.

Another way of affecting the surface and thus the translucency is to ensure that the finished ceramic material has a surface layer which functions to refract index-match between the material and the surrounding layer. This layer may be a liquid rlrri, e.g. water or saliva. The formation of such a film on the hydrated material can be achieved by giving the material a hydro surface, which in turn can be achieved by pre-hydrating the powder material, by chemical or physical coating of a hydrochloric substance on the material or by chemical exposure of the material so that a hydro fi l surface is created. The wetting angle of saliva or water on the material is suitably between 130-160 °, preferably 130-150 °, even more preferably 135-145 °. 10 15 20 25 30 519 990 P162l Additives that give b / ster Ceramic layer materials, ie materials with a given cleavage surface e.g. mica and feldspar, can be used as additives to give the material luster and mechanical strength.

Particularly preferred is the use of fl uor mica, as it is a beneficial source of fl uor for the teeth. Suitably at least 1% by volume, preferably at least 5% by volume, but not more than 20% by volume, preferably not more than 15% by volume of layer material, is used in the powder material.

Mechanical strength can also be achieved with the aid of such a ceramic layer material thanks to its lamellar structure, which makes it function as a reinforcing material. The particles should be less than 50 microns, preferably less than 20 microns and even more preferably less than 10 microns.

Fluorescent additives For the production of fluorescents, fluorescent additives are suitably used, especially substances containing ions of rare earth metals: Ce, Pr, Nd, Prn, Sm, Eu, Gd, Tb and Dy. Particularly preferred are additives containing Eu ions as they give a ores uorescence similar to that of the natural tooth. In another aspect, it is preferred with ores uorescent additives containing F ions. Examples of preferred fl uorescent additives are fl uorapatites with dissolved lanthanide and oxides of lanthanides.

The additives of this type may be present in total amounts of at least 0.1% by volume, preferably at least 0.5% by volume and even more preferably at least 1% by volume, but not more than 15% by volume, preferably not more than 10% by volume and even more preferably not more than 8% by volume, in the powder material.

The opal effect Opal effect, implying the impression of translucency, can be achieved by using orange and blue hues in the material or on the surface of the finished ceramic material.

EXAMPLE 1 A series of experiments were performed to study the effect of various translucency or radioopacity promoting additives on light opacity and radioopacity of the hydrated ceramic material. Description of raw materials Calcium alumininate of the phases CaOvAlzOg and CaOO2Al; O3 contained in e.g. Ca-aluminate cement (Alcoa alternatively LaFarge) BaFQ, BaSO4 (Merk), AlgOg (Baikalox), SnG; (Aldrich), Dental glass (Schottsvenska), Silicate glass (Schottsvenska) The experiments a) -]) below describe: a) The opacity of hydrated calcium aluminates, without action or additive, but with radioopacity giving results (reference). (b) Effect of removal of radiopaulents on (a) (c) Effect of radiopacity-providing or on b), BaSO4 d) e) Effect of radiopacity-giving agents on b), BaO-SiO2-B2O3-A12O3 glass. t) Effect of radiopacity-giving elements on b), BaO-F-SiO2-B2O3-A12O3 glass g) Effect of radioopacity-giving elements on b), SiO2-B2O3-Al2O3-F-SrO-NazO-CaO-ZnO-La2O3-ZrO2 glass . h) Effect of hardening fi ller on b), A120; i) Effect of opacity reducing fi or on b), silicate glass j) Effect of combination of different additives on b) Calcium aluminates, CaO-Al 2 O 2; and CaOO2Al2O3, with a molar ratio of 1: 1 mixed with part or particles and secondary additives (all content indications in relation to the calcium aluminate content) as below. a) Addition of ore, 15 vol-% SnOg (refractive index 2) b) No addition of ore. c) Addition of 15 vol% BaSO4 (refractive index 1.6) d) Addition of 15 vol% BaFg (refractive index 1.48) e) Addition of 40 vol% glass with the composition 30 wt% BaO-50 wt% SiO 2 -10 wt% B; O3-1O wt% AlgO 2, (refractive index 1.55) i) Addition of 40 vol% glass with the composition 30 wt% BaO-1 wt% F-49 wt% SiO 10% by weight of Al 2 O 3; (refractive index 1.55) g) Addition of 40 vol% glass with the composition 30 wt% SiO 2 -S wt% B; O3-5 wt% Al wt% CaO-10 wt% ZnO-5 wt% La2O3-10 wt% ZrO2 (refractive index 1,606). h) Addition of 40% by volume of Al 2 O 3; (refractive index 1.76) i) Addition of 40 vol% silicate glass (refractive index 1.46) j) Addition of secondary phases in the form of 10 vol% silicate glass and 30 vol% BaO-SiO2 glass. 10 15 20 519 990 ll »P1621 The mixtures are ground in a ball mill with inert grinding balls of silicon nitride with a degree of filling of 35%. Isopropanol is used as the grinding fluid. After evaporation of the solvent, cylindrical crude bodies with a diameter of 10 mm and a height of 1 mm were prepared, which were wetted with water. The materials were then kept moistened at 37 ° C for one week before measurements of translucency / light opacity or radioopacity. The measurements of opacity were performed according to ISO 9917 (100% means opaque and 35% to 90% translucency) and the measurements of radioopacity according to AN SI / ADA Specification No. 27 (1 mm specimen as opaque as 2mm Al). The results are reported in Table 1.

Table l Test designation Opacity (%) Radioopacity (C010) A 100 Yes B 73 No C 75 Yes D 77 Yes E 65 Yes F 65 Y a G 55 Y a H 73 No I 63 No J 63 Yes The results show that a translucent and radiopaque product can be produced. Furthermore, it appears that the refractive index of the additive material is crucial for both radioopacity and translucency to be obtained simultaneously.

EXAMPLE 2 Experiments were performed to study the effect of grain size of the calcium aluminate and porosity of the hydrated material on the opacity of the hydrated material.

Description of raw materials Calcium aluminate of the phases CaO ~ Al2O3 and CaOø2Al2O3 included in e.g. Ca-aluminate cement (Alcoa or LaFarge). 516 20 25 30 35 519 990 12 P1621 The examples below a) -g) bes / Wiver a) The opacity of the calcium aluminate in hydrated aluminate (reference). Impact of reduced average comorbidity of calcium aluminates on. c) Impact of reduced average grain size of the calcium aluminate compared to b) on a). Effect of sieving c on a). Effect of reduced porosity of the finished hydrated material on. f) Effect of increased porosity of the finished hydrated material on a) g) Effect of d) and e) on a) Calcium aluminates, CaO fi AlgO 2 and CaOO 2 Al 2 O 3, with the molar ratio 1: 1 used in the examples.

The materials are ground in a ball mill with inert mills of silicon nitride with a degree of fidelity of 35%. Isopropanol is used as the grinding fluid. To vary the grain size of the calcium aluminates, the meal time was varied. The grain size was measured by laser diffraction and was determined weighted against the volume mean value D [4,3]. The porosity of the hydrated material was varied by using different mechanical pressures in the manufacture of the specimens. Porosity was measured using a scanning electron microscope and image analysis.

After evaporation of the solvent, cylindrical crucibles with a diameter of 10 mm and a height of 1 mm were prepared, which were wetted with water. The materials were then kept moistened at 37 ° C for one week before measuring opacity. The measurements of opacity were performed according to ISO 9917.

In the examples, the following actions were performed: a) The calcium aluminates were ground to a grain size distribution with all grains below 40 micrometers. By controlling the mechanical pressure in the manufacture of the hydrated material, the porosity of the finished hydrated material was controlled to 10%. b) The calcium aluminates were ground to a grain size distribution with all grains below 20 micrometers. By controlling the mechanical pressure in the manufacture of the hydrated material, the porosity of the finished hydrated material was controlled to 10%. c) The calcium aluminates were ground to a grain size distribution with all grains below 10 micrometers. By controlling the mechanical pressure in the manufacture of the hydrated material, the porosity of the finished hydrated material was controlled to 10%. 10 15 20 25 Pl62l d) Q 519 990 n 13 The calcium aluminates were ground to a grain size distribution with all grains below 10 micrometers. When grinding, most of the grains were less than 3 micrometers away. After sieving, 90% of the grains were found between 3 and 10 micrometers. By controlling the mechanical pressure in the manufacture of the hydrated material, the porosity of the finished hydrated material was controlled to 10%.

The calcium aluminates were ground to a grain size distribution with all grains below 40 micrometers. By controlling the mechanical pressure in the manufacture of the hydrated material, the porosity of the finished hydrated material was controlled to 5%.

The calcium aluminates were ground to a grain size distribution with all grains below 40 micrometers. By controlling the mechanical pressure in the manufacture of the hydrated material, the porosity of the finished hydrated material was controlled to 20%.

The calcium aluminates were ground to a grain size distribution with all grains below 10 micrometers. After grinding, most of the grains were sifted under 3 micrometers away.

90% of the grains were found between 3 and 10 micrometers. By controlling the mechanical pressure in the manufacture of the hydrated material, the porosity of the finished hydrated material was controlled to 5%.

The results are reported in Table 2.

Table 2 Sample designation Opacity (%) (C010) A 74 B 70 C 86 D 64 E 66 F 96 G 60 The results show that a low porosity and a narrow grain size distribution are advantageous to achieve a lower opacity.

EXAMPLE 3 Experiments were performed to study the effect of the surface unit on the opacity of the material. 10 15 20 25 30 519 990 H P1621 Description of raw materials Calcium aluminate of the phases CaO-Al 2 O 2; and CaOO 2 Al 2 O 3 contained in e.g. Ca- aluminate cement (Alcoa alternative LaFarge).

Description of grinding and polishing To produce surfaces with different roughness, the hydrated material was sanded with sandpaper from 80 mesh (SiC) down to 1 micrometer of diamond particles on canvas. Before measuring translucency, the roughness of the surface (IQ value) was measured using a trailing needle (Alpha-step, Tencor Instruments).

The examples below aj- e) describe a) the translucency of the calcium aluminate in hydrated aluminate, coarsely ground with 80 mesh SiC paper. b) Impact of grinding with 320 mesh SiC paper on a) c) Impact of grinding with 500 mesh SiC paper on a) d) Impact of grinding with 1200 mesh SiC paper on a) e) Impact of polishing with diamond paste ( one micrometer diamond grain) on a) Calcium aluminates, CaO-AlQO; and CaOOZAI2O3, with a molar ratio of 1: 1 were used in the examples.

The mixtures are ground in ball mills with inert mills of silicon nitride with a degree of filling of 35%. Isopropanol is used as the grinding fluid. After evaporation of the solvent, cylindrical crucibles with a diameter of 10 mm and a height of 1 mm were prepared, which were wetted with water. The hydrated specimens were then ground with sandpaper according to the test schedule. The materials were then kept sealed at 37 ° C for one week before measuring opacity. The measurements of opacity were performed according to ISO 9917. The results are reported in Table 3. 10 15 20 25 30 519 990 P 162 1/5 Table 3 Sample designation Opacity (%) Ra (um) (C070) A 1 00 1 5 B 76 2 C 71 0.5 D 67 0, 1 E 63 0.04 The results show that a translucent product can be obtained by checking the roughness of the surface.

EXAMPLE 4 Experiments were performed to study the effect of the composition on the binder phase on the opacity of the hydrated material.

Description of raw materials Calcium aluminate of the phases CaOvAlzOg and CaO22A12O3 and 3CaO0A12O3.

Experiments a) -aD below describe: a) Opacity of hydrated calcium aluminate, hydrated from a powder mixture with the molar ratio CaOvAlgOg: CaO ~ 2A12O3 = 1: 1 (reference). b) Opacity of hydrated calcium aluminate, hydrated from a powder mixture consisting of CaOOAl2O3. c) Opacity of hydrated calcium aluminate, hydrated from a powder mixture with the mole ratio 3CaOOAl2O3: CaO-AlZO; = 1: 1. d) Opacity of hydrated calcium aluminate hydrated from a powder mixture consisting of 3CaOOAl2O3 Isopropanol is used as the grinding fluid. Evaporation of the solvent produced cylindrical crude bodies with a diameter of 10 mm and a height of 1 mm, which were wetted with water. The materials were then kept oriented at 37 ° C for one week before measuring opacity. The measurements of opacity were performed according to ISO 9917. The results are reported in Table 4. 10 15 20 25 30 519 990 P1621 in agg: get 14, in Table 4 Sample designation Opacity (%) (Cor / o) A 74 B 60 C 55 D 40 Of the results it appears that a translucent product can be prepared. Furthermore, it is possible that the opacity can be reduced by choosing the phase composition of the binder phase.

EXAMPLE 5 Experiments were performed to study the effect of mica on the lyme of the material.

Description of raw materials Calcium aluminate of the phases CaOßAlgOg and Ca002Al2O3 included in e.g. Ca- aluminate cement (Alcoa or LaFarge), mica (Chernieni minerals).

The examples below a) - e) describe a) The gloss of the calcium aluminate in hydrated aluminate, without action or additive. b) Effect of mica addition on a) Calcium aluminates, CaOOA12O3 and CaO02Al2O3, with a molar ratio of 1: 1 mixed with secondary additives (all content indications in relation to the calcium aluminate content) as below. a) No additive. b) Addition of 10 vol% mica The mixtures are ground in ball mills with inert mills of silicon nitride with a degree of filling of 35%. Isopropanol is used as the grinding fluid. After evaporation of the solvent, cylindrical crucibles with a diameter of 10 mm and a height of 1 mm were prepared, which were wetted with water. The materials were then kept moist at 37 ° C for one week before visual inspection of the appearance.

The results visually show that a greater luster is obtained in the material. 10 15 20 25 30 519 990 P1621 'li? EXAMPLE 6 Experiments were performed to study the effect on fl uorescence of the material of various fl uorescence-promoting additives.

Description of raw materials Calcium aluminate of the phases Ca00Al2O3 and CaO02Al2O3 included in e.g. Ca-aluminate cement (Alcoa alternative LaFarge), CaFz (Aldrich), or uorapatite with lanthanide dissolved, oxide of lanthanide The examples below a) - e) describe a) the ores uorescence of calcium aluminate in hydrated aluminate (reference). b) Effect of secondary phase on a), CaFg c) Effect of secondary phase on a), fl uorapatite with dissolved lanthanide (Eu) d) Effect of secondary phase on a), oxide of lanthanide e) Effect of combination of different additives on and calcium aluminates, CaO-AIQO; and CaOO2Al2O3, with a molar ratio of 1: 1 mixed with part or particles and secondary additives (all content indications in relation to the calcium aluminate content) as below. a) No addition of or. b) Addition of 5 vol% CaFg c) Addition of 5 vol% or uorapatite with dissolved Eu d) Addition of 5 vol% ceria oxide e) Addition of 3 vol% CaFg and 3 vol% fl uorapatite with dissolved Eu The mixtures are ground in ball mill with inert silicon nitride grinding balls with a filling degree of 35%. Isopropanol is used as the grinding fluid. After evaporation of the solvent, cylindrical crucibles with a diameter of 10 mm and a height of 1 mm were prepared, which were wetted with water. The material was then kept moistened at 37 ° C for one week before ores uorescence measurements. The measurements of oresorescence were performed on a spectrophotometer (Minolta).

The results are reported in Table 5. 10 l5 20 25 519 990 P1621 l8 Table 5 Sample designation Fluorescence, excited with UV light 7L <400 nm.

A No B Yes, blue C Yes, blue D Yes, blue-green E Yes, blue The results show that a fluorescent product can be obtained by adding a fluorescent substance.

EXAMPLE 7 Experiments were performed to study the effect of different whiteness of raw materials on the opacity of the material.

The raw materials used were calcium aluminate of the phases CaOOAl 2 O 3 and CaOO 2 Al 2 O 3 contained in e.g. Ca-aluminate cement (Alcoa alternative LaFarge).

Experiments a-b) describe the effect of whiteness (according to ASTM E313) of the raw materials on the opacity of the hydrated material. a) Calcium aluminate with a whiteness of 60 b) Calcium aluminate with a whiteness of 72 The mixtures are ground in a ball mill with inert mills of silicon nitride with a degree of filling of 35%. Isopropanol is used as the grinding fluid. After evaporation of the solvent, cylindrical test pieces of 10 mm diameter and 1 mm height were prepared, which were wetted with water. The materials were kept moist at 37 ° C for one week before measuring opacity.

The measurements of opacity were performed according to ISO 9917 (100% means opaque and 35% to 90% translucency). The results are reported in Table 6, Table 6 Test designation Opacity (%) (Co fl o) A 98 B 73 519 990 P1621 'af -. CI The results show that the whiteness of the raw materials has an effect on the opacity of the material, in such a way that a whiter raw material gives a lower opacity.

The invention is not limited to the reported embodiments but can be varied within the scope of the patent claims.

Claims (1)

1. 0 15 20 25 30 35 519 990 P1621 i .ZÖ PATENTKRAV. Powder material, the binder phase of which consists mainly of a cement-based system, which powder material has the ability to hydrate after permeation with a liquid reacting with the binder phase to a chemically bonded ceramic material, preferably for dental purposes, characterized in that the powder material has a composition and / or structure to give the ceramic material translucency in a hydrated state. Powder material according to claim 1, characterized in that said binder phase consists at least mainly of calcium aluminate cement. . Powder material according to claim 1 or 2, characterized in that said composition and / or structure is suitable for giving the ceramic material a translucency corresponding to 35-90%, preferably 40-85% and even more preferably 50-80% opacity. . Powder material according to any one of claims 1-3, characterized in that it is in the form of a crude press body which has a compact degree of 55-67% by volume of solid phase, preferably 57-63% by volume of solid phase and even more preferably 58-61. volume% solid phase. . Powder material according to one of Claims 1 to 3, characterized in that it is present in loose powder form or in the form of granules. . Powder material according to any one of the preceding claims, characterized in that the binder phase is optimized for translucency of the ceramic material, preferably in terms of physical or chemical properties of the binder phase and / or in that the powder material is optimized for translucency of the ceramic material, preferably in the form of one or fl your additives suitable to give the ceramic material translucence. . Powder material according to one of the preceding claims, characterized in that the binder phase of the powder material is optimized for translucency of the ceramic material, preferably in teeth of whiteness value and / or particle size and / or choice of phase composition of the binder phase. P162l 519 990 .2 / Å Powder material according to claim 7, characterized in that the whiteness value of the binder phase exceeds 70, preferably exceeds 74 according to ASTM E313. Powder material according to claim 7, characterized in that the particle size of the majority of particles is less than 80 μm, preferably less than 20 μm and even more preferably less than 15 μm, but exceeds 1 μm, preferably exceeds 2 μm and even more preferably exceeds 3 μm or less than 300 nm, preferably less than 200 nm. Powder material according to claim 7, characterized in that the binder phase is mainly ll. consists of 3CaOOAl2O3 and / or CaOøAlgOg. Powder material according to any one of the preceding claims, characterized in that it comprises one or more additives which have a refractive index in visible light which deviates no more than 15%, preferably no more than 10% and even more preferably no more than 5% from the refractive index refractive index when the binder phase is hydrated . Powder material according to claim 1 1, characterized in that said additive 13. 14. 15. consists of glass particles, preferably particles of silicate glass. Powder material according to claim 1, characterized in that said additive is also suitable for giving the ceramic material radioopacity, said additive containing an atom type with a density above 5 g / cma, preferably Zr, La, Ta, Zn, Ba and / or Sr, and which additive preferably constitutes a glass, most preferably a silicate glass, and / or which additive preferably also contains fl uor. Powder material according to any one of the preceding claims, characterized in that its composition and / or structure is also intended to give the ceramic material luminescence or other optical effects which are similar to optical effects in natural tooth, wherein said luminescence or optical effects constitute some effect. in the group consisting of luster, fl uorescence, opalescence, iridiscence and opal effect. Powder material according to any one of the preceding claims, characterized in that it comprises one or more additives which are suitable for giving the ceramic material fluorescence, preferably one or more additives which comprise ions of rare earth metals, preferably ions of Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb and / or Dy, most preferably ions of Eu and / or one or fl era fl uorescent 10 15 20 25 30 35 P1621 16. 17. 18. 19. 20. 21. 22. 23. 23. 519 990 22 additives comprising fl uoride ions. Powder material according to any one of the preceding claims, characterized in that it comprises one or more additives which give the ceramic material luster, preferably an additive which comprises a ceramic layer material, and / or that the powder material comprises one or more additives which give the ceramic material an opal effect. form of blue and orange colors. Chemically bonded ceramic material whose bonding phase consists mainly of a cement-based sister, preferably for dental purposes, is characterized in that the material has a composition and / or structure which gives the material translucence. Ceramic material according to claim 17, characterized in that said binder phase consists at least mainly of calcium aluminate cement. Ceramic material according to claim 18, characterized in that said binder phase has a molar ratio of Al2O303H2O to 3CaOOAl2O306H2O of at most 2: 1, preferably less than 1: 5 and even more preferably less than 1:10. Ceramic material according to any one of claims 17-19, characterized in that it has a translucency corresponding to 35-90%, preferably 40-85% and even more preferably 50-80% opacity. Ceramic material according to any one of claims 17-20, characterized in that it has a hardness of at least 50 HV, preferably at least 100 HV and even more preferably 120-300 HV. Ceramic material according to any one of claims 17-21, characterized in that it has a porosity below 20%, preferably below 10% and even more preferably below 5%. Ceramic material according to any one of claims 17-22, characterized in that it has a surface, which surface gives the material translucence, said surface preferably having a surface unit, measured as Ra, lower than 10 μm, preferably lower than 2 μm and even more preferably lower than 1 μm, and / or has a surface layer matching 519 990 P1621 'f 2.3 refractive index between the material and air. Ceramic material according to any one of claims 17-23, characterized in that it has a wetting angle for saliva or water on the material between 130-160 °, preferably 130-150 °, even more preferably 13 5-145 °. Ceramic material according to any one of claims 17-24, characterized in that it is composed of a hydrated powder material according to any one of claims 4-16.