Blank and method for manufacturing the blank

Abstract

The present invention relates to a blank for use in the production of a dental product comprising, or containing, ZrO 2 stabilized with Gd 2 O 3 as a main stabilizer in an amount of 2 to 6 mol% based on the content of ZrO 2 and at least one oxide from the group of Y, Yb, Dy, Nd, Ca, Ce, Mg, Sm, Er, Tb, La as a secondary stabilizer in an amount of 0.05 to 2.0 mol% based on the content of ZrO 2 and to a method for producing the blank.

Description

Technical Field

[0001] The present invention relates to a blank for use in the manufacture of dental products, such as dental restorations, veneers, or implant components, which consists of or contains at least gadolinium(III) oxide (Gd 2 O 3 )-stabilized zirconium dioxide (ZrO 2 ).

Background Art

[0002] The corresponding blank can be found in EP2956427B1. In order to achieve the purpose of providing a dental ceramic with good mechanical properties, the content of tetragonal zirconium dioxide is 94% to 96% by volume.

[0003] WO99 / 47065A1 discloses a method for manufacturing a dental prosthesis based on a zirconium dioxide blank that can be mounted on a pre-prepared residual root. The blank consists of a pre-sintered zirconium dioxide disk, from which a mold corresponding to the dental prosthesis is machined taking into account the shrinkage behavior during full or final sintering. The starting powder may contain coloring elements in the form of oxides.

[0004] Inorganic-inorganic composite materials and methods for their manufacture are known from WO2005 / 070322A1. To manufacture the composite material, after shaping and pre-sintering, a porous crystalline oxide ceramic compact is produced from an oxide ceramic powder of ZrO 2 (zirconium dioxide), an infiltrant is applied to this under vacuum at room temperature, and the oxide ceramic is sintered in an air atmosphere and at normal pressure to compress the inorganic-inorganic composite material. This means is intended to bring about an improved aesthetic effect.

[0005] WO2015 / 199018A1 discloses a colored translucent zirconia body composed of zirconia stabilized with yttrium oxide, erbium oxide, iron oxide, cobalt oxide, and aluminum oxide.

[0006] Blanks made of zirconia, which are used in the manufacture of dental prostheses and consist of multiple layers with different chemical compositions, are known from US8936845B2. The individual layers have different proportions of yttrium oxide.

[0007] A zirconia blank for the manufacture of dental products according to WO2014 / 062375A1 has at least two material regions with different proportions of tetragonal and cubic crystal phases, with the proportion being large in one region and less than 1 in the other region.

[0008] EP2371344A1 relates to a ceramic body enriched with a stabilizer from the surface to a desired depth.

SUMMARY OF THE INVENTION

[0009] An object of the present invention is, inter alia, to achieve that the blank has the strength required for use as a dental product, particularly a restoration or an implant, while at the same time exhibiting the optical properties desired to meet aesthetic requirements. A blank intended for dental restorations should have an appearance corresponding to natural teeth.

[0010] To achieve one or more aspects, the present invention provides that zirconia is stabilized with GdO as a main stabilizer having a content of 2 - 6 mol% with respect to the content of ZrO 2 and at least one oxide from the group of Y, Yb, Dy, Nd, Ca, Ce, Mg, Sm, Er, Tb, La as a secondary stabilizer having a content of 0.05 - 2.0 mol% with respect to the content of ZrO 2 O 3 and ZrO 2 is defined as being stabilized.

[0011] Surprisingly, when gadolinium(III) oxide is used as the main stabilizer, high fracture toughness can thereby be achieved simultaneously with good optical properties, and when at least one other stabilizer is used as a co-stabilizer, the fracture toughness does not decrease significantly, but at the same time an increase in strength has been found. As the content of the stabilizer increases, the optical properties also improve.

[0012] In particular, it is specified that the blank contains at least one coloring oxide from the group of Pr, Er, Fe, Co, Ni, Ti, V, Cr, Cu, Mn, Tb.

[0013] The present invention preferably has a proportion of Gd 2 O 3 which is specified to be 2 to 5 mol%, particularly preferably 2.5 to 4 mol%, very particularly preferably 3 to 4 mol% with respect to the content of ZrO 2

[0014] It should also be emphasized that the tetragonal crystal phase of zirconium dioxide in the blank is 40 to 80% by volume, particularly 45 to 75% by volume.

[0015] In contrast to the blank containing Gd 2 O 3 as the main stabilizer, the proportion of the tetragonal phase of stabilized zirconium dioxide is intentionally reduced in order to obtain a relatively high proportion of the cubic crystal phase in order to achieve the desired translucency. However, regardless of this, the required strength or fracture toughness and bending strength are provided in order to meet the mechanical requirements for restorations or implant components.

[0016] Due to the essential inclusion of at least one coloring oxide, an optical appearance that meets aesthetic requirements can be achieved. The coloring of the implant component presents the advantage that it is hardly noticeable compared to, for example, an implant made of titanium when the implant becomes visible due to a change in the gingiva.

[0017] In particular, when a single co-stabilizer or several co-stabilizers are present, the content of the co-stabilizer should be 0.05 to 2.0 mol%, particularly 0.2 to 0.8 mol%, based on the zirconium dioxide content.

[0018] Regarding the color effect to be achieved, in particular, the proportion of one or more coloring oxides is defined to be at most 1.5% by weight of the blank.

[0019] When it is possible to provide a single layer, and thus a monochromatic blank, in accordance with the teachings of the present invention, in particular, the blank is defined to have at least two regions with different compositions from each other.

[0020] The total content of the stabilizer can be the same in each region.

[0021] In other words, the total content of the stabilizer in each layer can be the same, and the content of the coloring oxide in the layer is different from each other.

[0022] However, the total content and / or the stabilizer may also be different in the regions. Y 2 O 3 When Y is used as a stabilizer, its content in the layer can be the same.

[0023] As described above, Gd of the stabilizer 2 O 3 is the main stabilizer, that is, this is mainly used for stabilizing the tetragonal crystal phase of zirconium dioxide, so the additional stabilizer is called a co-stabilizer.

[0024] Therefore, the ratio of the main stabilizer Gd 2 O 3 to the total of the co-stabilizer or co-stabilizers is 1:1 to 1:120, preferably 1:2 to 1:40, particularly preferably 1:4 to 1:10, and particularly preferably 1:5 to 1:7.

[0025] Particularly for dental restorations manufactured from blanks, in order to achieve the desired fluorescence properties, the blank or a region of the blank contains at least one element that produces a fluorescence effect, particularly at least one oxide from the group of Bi, Tb, Tm, Pr, in a proportion of 0.005 to 2.0 wt%, preferably 0.005 to 0.5 wt%.

[0026] To enable the production of dental restorations, such as frameworks, bridges, crowns, partial crowns, from blanks that can be made available without costly reworking, while simultaneously meeting the desired aesthetic requirements and having the necessary strength in very stressed regions, it is proposed in particular that a first region has cavities in which a second region having a composition different from that of the first region extends.

[0027] The first region can optionally have different internal shapes and have a plurality of cavities in which a plurality of second regions extend. The first region has greater translucency than the second region, and the strength of the second region is greater than the strength of the first region.

[0028] In particular, the blank is a multi-layer comprising at least one bottom layer and one top layer of different compositions. The layers contain at least one first coloring oxide, and its proportion in the bottom layer having the first coloring oxide is lower than its proportion in the top layer having the first coloring oxide.

[0029] Regardless of this, the blank should have at least three layers. The intermediate layer between the upper layer and the lower layer consists of the materials of the upper layer and the lower layer.

[0030] Particularly to meet aesthetic requirements, a further proposal of the present invention is that the first coloring oxide is at least one oxide from the group of Co, Mn, Ni, Cr, particularly Co 2 O 3 or MnO 2 or a mixture thereof.

[0031] The present invention also relates to a method for manufacturing a blank intended for manufacturing dental products, in particular dental restorations, veneers, implant parts, wherein a powder ceramic material containing zirconium dioxide stabilized with at least one stabilizer is pressed and then subjected to at least one heat treatment, whereby the zirconium dioxide is stabilized with gadolinium(III) oxide (Gd 2 O 3 ) as a main stabilizer in a content of 2 to 6 mol% relative to the zirconium dioxide content, and at least one oxide from the group of Y, Yb, Dy, Nd, Ca, Ce, Mg, Sm, Er, Tb, La as a secondary stabilizer in a content of 0.05 to 2.0 mol% relative to the content of ZrO 2 . The method is characterized in that.

[0032] At least one coloring oxide from the group of Pr, Er, Fe, Co, Ni, Ti, V, Cr, Cu, Mn, Tb is preferably added to the ceramic material.

[0033] In particular, the present invention relates to a method for manufacturing a blank from a ceramic material, wherein at least two layers of the ceramic material consisting of the above mixture are introduced into the die in layers, the layers can have different compositions, and then after the introduction of the layers, they are pressed and then sintered. After the introduction of the first layer, when viewed along its surface, the first layer is structured on the surface such that in some regions it has different heights, i.e., does not have a uniform filling height, and then a second layer having a composition different from that of the first layer is introduced into the mold. The method is characterized by this.

[0034] Alternatively, after the first layer is applied, an intermediate layer made of a ceramic material from a mixture according to the present invention, which is different from the mixture of the first layer, may be filled into the die, the material of the first layer is mixed with the material of the intermediate layer, and then the second layer may be introduced into the die. It is particularly provided that the material of the intermediate layer is mixed with the material of the first layer over a height corresponding to twice or approximately twice the height of the intermediate layer, starting from the free surface of the intermediate layer. Further, it is particularly provided that the material used for the intermediate layer is identical to the material of the second layer.

[0035] According to the present invention, according to a first alternative, a first layer of a pourable powder material is introduced into the die. After the material is introduced, the surface is then smoothed in order to form a structure such that in particular there are ridges and valleys that are parallel to each other, in particular concentric or parallel to each other. For this purpose, it is particularly provided that the structure is formed by an element that moves relative to the first layer, in particular rotates, and structures the first layer in a cross-section formed in particular like a wave, a comb, or a sawtooth in its surface area. The surface is, so to speak, "raked" in order to form a structure, i.e., alternating ridges and valleys.

[0036] In particular, it is specified that the structure is introduced such that the volume of the ridges is the same as or approximately the same as the volume of the depressions or valleys.

[0037] The sawtooth element should preferably be symmetric and have V-shaped teeth whose sides enclose an angle of 15° to 45°. The distance between consecutive teeth, i.e., the distance from tip to tip, should be 1 to 4 mm, preferably 1 mm to 3 mm.

[0038] Next, a pourable powdered second ceramic material is introduced into the mold, which starts from the depressions within the structure formed by the valleys and increases in quantity, so that as a result, the proportion of the second layer increases quasi-continuously over the height of the ridges. After the surface is smoothed, the layer is pressed.

[0039] Subsequently, pre-sintering is carried out at a temperature in the range of 700 °C to 1100 °C, particularly 800 °C to 1000 °C, for a period of, for example, 100 minutes to 150 minutes. The blank thus produced is then machined, for example by milling and / or grinding, so that the desired dental restoration is produced, which is then sintered.

[0040] Sintering is carried out at a temperature in the range of 1200 °C to 1600 °C for a time of, for example, 10 minutes to 250 minutes.

[0041] In particular, sintering should be carried out in the temperature range of 1400 °C to 1500 °C, preferably 1400 °C to 1450 °C.

[0042] The temperatures and times of the pre-sintering or sintering described above apply to different layer shapes, layer sequences, and different numbers of layers. Of course, this also includes the production of blanks consisting of a uniform material, i.e., blanks that do not consist of layers or regions of ceramic materials with different compositions with respect to the starting materials.

[0043] Immersing the layers has the advantage that different physical and optical properties can be achieved over the height of the blank. Thus, if the first layer is colored to the required degree, a tooth-colored edge region can be achieved after sintering, i.e., finishing or full sintering, which has a continuous decrease in strength over the transition region created by the materials of the first and second layers that penetrate each other. The dental restoration is then produced from the blank, taking into account the path of the layers, particularly by milling, and the dental restoration is "fitted" into the blank such that the cutting edge of the tooth is within the region of the second layer.

[0044] According to the teachings of the present invention, there is a continuous transition between the layers such that the color or translucency decreases or increases continuously.

[0045] Using Gd as the main stabilizer 2 O 3 brings the advantage that particularly high edge stability of the dental product can be achieved. Using Y as the main stabilizer2 O 3 ZrO stabilized by 2 Compared with, the wall thickness can be up to 20% thinner.

[0046] Preferably, in order to create a structure that can also be described as wavy or serrated by shifting the material on the surface to achieve the first layer, the structuring element is rotated around an axis running particularly along the longitudinal axis of the mold, so that the layer material can be mixed. It is also possible to form the structure by a pressure element acting in the direction of the surface on the first layer, which particularly has a bulge on its surface and a depression therebetween, and the concave shape is imprinted on the surface of the first layer by an element that can also be called a plunger. Next, as described above, the ceramic material of the second layer is filled, then only the layers are pressed together, and then the pressed part is smoothed for pre-sintering.

[0047] The subject matter of the present invention is also a dental restoration, particularly a dental product in the form of a crown, partial crown, or bridge, wherein the restoration comprises at least a first layer on the root side and a second layer on the incisal side when viewed in the tooth axis direction, the strength of the first layer is greater than the strength of the second layer, and the light transmittance of the second layer is greater than the light transmittance of the first layer.

[0048] The layer should contain a first coloring oxide, particularly at least one oxide from the group of Co, Mn, Ni, Cr, preferably Co 3 O 4 or MnO 2 or a mixture thereof, and the proportion in the first layer is lower than the proportion in the second layer.

[0049] Furthermore, it is proposed that the dental product is an integrated implant system consisting of an implant and an abutment, but this can also be made into two parts in the usual way.

[0050] Further details, advantages, and features of the present invention result not only from the claims, the features individually and / or combined therefrom, but also from the following description of preferred exemplary embodiments taken from the drawings and their description.

Brief Description of the Drawings

[0051]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0052] To manufacture a blank, a powdered ceramic material is first produced, the main component of which is stabilized zirconium dioxide stabilized with Gd as the main stabilizer 2 O 3 and one or more sub-stabilizers. At least one oxide from the group of Y, Yb, Dy, Nd, Ca, Ce, Mg, Sm, Er, Tb, La with a content of 0.05 to 2.0 mol% with respect to the content of ZrO 2 is considered as a sub-stabilizer.

[0053] Therefore, the ratio of the main stabilizer to the total of the secondary stabilizer or secondary stabilizers should be 1:1 to 1:120, preferably 1:2 to 1:40, particularly preferably 1:4 to 1:10, and especially preferably 1:5 to 1:7 in mol% based on zirconium dioxide.

[0054] The total content of the stabilizer should be 2 mol% to 8 mol%.

[0055] At least one coloring oxide is also added, and its proportion by weight in the ceramic material should be 1.5 wt% or less. In particular, as the coloring oxide, Fe 2 O 3 , Er 2 O 3 , Co 3 O 4 or Tb 2 O 3 or a mixture of two or more of these oxides is selected.

[0056] The mixture contains HfO 2 < 3.0 wt%, Al 2 O 3 < 0.3 wt%, and unavoidable admixtures ≤ 0.2 are also included. If necessary, elements that bring about a fluorescence effect such as bismuth or thulium can be added, and the content of each oxide should be 0.005 to 2.0 wt%, particularly 0.005 to 0.5 wt%.

[0057] The correspondingly prepared mixture 1 is poured into the mold or die 2 and pressed. The green body produced in this way, after being removed from the mold, is then subjected to a first heat treatment in the range of 800 °C to 1000 °C for a period of 100 minutes to 150 minutes. The first step is debinding if a binder has been added to the starting mixture, and then pre-sintering. The pre-sintered blank is then machined, for example, to mill artificial teeth. Next, sintering, i.e., full sintering in a temperature range preferably of 1400 °C to 1500 °C, is carried out, and values in the range of 1400 °C to 1450 °C are of particular note. The sintering process is carried out over a period of 10 minutes to 250 minutes. In this way, monochromatic dental products are manufactured. This can be a dental restoration or, for example, an implant system which, when emphasized in particular, consists of an implant and an abutment and can thus be manufactured in one piece or (as usual) in two parts.

[0058] Using Gd as the main stabilizer 2 O 3 contrary to the proposals from the prior art, has the advantage that the proportion of the tetragonal crystal phase is relatively small, specifically 40 vol% to 80 vol%, preferably 45 vol% to 75 vol%, and as a result, the proportion of the cubic crystal phase is relatively high, and thus the desired light transmittance can be achieved. Regardless of the relatively small proportion of the tetragonal crystal phase, the corresponding sintered blank has the strength, fracture toughness, and hardness required for use in the dental field.

[0059] With respect to the zirconium dioxide content, the content of Gd 2 O 3 is 3 mol% of Gd 2 O 3The biaxial strength measured in accordance with ISO 6872 using stabilized zirconia dioxide ranges from 750 MPa to 1000 MPa depending on the sintering temperature, and for zirconia dioxide stabilized with gadolinium(III) oxide (3 mol%) as the main stabilizer and ytterbium oxide (0.5 mol%) as the secondary stabilizer, it is in the range of 750 MPa to 850 MPa (a value achievable only when the tetragonal crystal phase exceeds 90% by volume). Experiments have shown this. 2 This is the value that can only be achieved at

[0060] 3 mol% Gd 2 O 3 -stabilized zirconia dioxide had a fracture toughness K IC in units of MPa m 0.5 and was in the range of 10 to 12 at a sintering temperature of 1350 °C to 1450 °C. A mixture of stabilizers consisting of 3 mol% gadolinium(III) oxide as the main stabilizer and 0.5 mol% ytterbium oxide as the secondary stabilizer had a K IC value of 8 to 10.5 MPa m 0.5 .

[0061] In contrast, for Y 2 O 3 (3 mol%)-stabilized ZrO 2 , the K IC value was 4 to 5 MPa m 0.5 .

[0062] With reference to Figures 2 to 7, a further aspect of the present invention is revealed for manufacturing monolithic products having regions close to the contour of the restorations for which the blanks are manufactured, particularly dental restorations such as crowns, partial crowns, or bridges.

[0063] It should be explained that blanks with regions of ceramic materials having different compositions and thus properties can be manufactured to achieve the desired optical and mechanical properties. The advantage of monolithic dentures is that, after being machined from the blank and then sintered, they can in principle be used immediately, for example, without the need to manually apply and bake the incisal edge.

[0064] The desired strength value can be set to meet the target. The same applies to color, translucency, and fluorescence properties.

[0065] According to Figure 2a, the die 10 is filled with powder of the first composition, which is used, for example, as a cutting material. The powder can contain a binder. The powder has, by way of example, the composition described above.

[0066] After filling the die 10 with the material 14, the open cavity 18 is formed by the press plunger 16, and the material itself is not in principle pressed. Rather, the material is shifted or slightly compressed. After the cavity is formed (Figure 2b), the press plunger 16 is removed to fill the cavity with the second ceramic material 20, and the second ceramic material 20 can be different from the first ceramic material 14 in that the content of the stabilizing oxide present in the material is the same for each material, but the added coloring oxides differ from each other in terms of either the element, the weight ratio, or a combination thereof.

[0067] The same is true when components intended to achieve fluorescence properties are added.

[0068] However, although each material may contain different amounts of stabilizer, at least each material contains Gd as the main stabilizer 2 O 3 and also a further secondary stabilizer.

[0069] After filling the cavity 18 with the second ceramic material 20 (Fig. 2c), in order to achieve compression, the material 14, 20, or a layer or region formed therefrom is then pressed by the lower and / or upper plungers 22, 24 within the die 10 of the press 12.

[0070] After pressing, the green body 28 has a density of about 3 g / cm 3 (Fig. 3). The pressing can be carried out within a desired conventional range, for example, at a pressure of 1000 - 2000 bar.

[0071] As can be seen from Fig. 3, after being compressed by the press plungers 22, 24 or, optionally, after pre-sintering, a second cavity 26 can be machined into the second material 20, for example, by milling.

[0072] However, in order to fill the material 20 that completely fills the bottom-side open cavity 18 according to Fig. 2c with a further material that should have a different composition from the material previously filled in the die, it is also possible to form a corresponding second cavity 26 by a press plunger (not shown).

[0073] Regardless of whether the second cavity 26 is present or not, the blank 28 is pre-sintered after pressing, particularly in the range of 800 °C to 1000 °C for a period of 100 to 150 minutes. If there is a binder in the material, debinding is carried out first and then pre-sintering.

[0074] The blank is provided with a holder for machining, for example, by milling and / or grinding, so that a desired dental product such as teeth can be machined from the blank 28 as described with reference to Fig. 5.

[0075] The manufactured tooth is preferably at least virtually arranged within the blank 28 such that the cutting region is within the region 32 formed by the first ceramic material 14 and the dentin region is partially within the second region 34 formed by the second ceramic material 20. Next, considering this data, the blank 28 is machined taking into account the shrinkage behavior of the materials.

[0076] FIG. 4 shows filling the first cavity 18 in the first ceramic material 14, filling the cavity 18 with the second ceramic material 20, and then introducing the second cavity 36 as required according to the method of FIG. 2b, and then introducing into the cavity 36 thus formed a third ceramic material 38 whose composition is different from that of the second ceramic material so that a particularly high strength can be achieved.

[0077] As explained in connection with FIG. 3, a cavity 40 can also be formed in the third ceramic material 38.

[0078] FIG. 5 shows how the tooth 42 in an exemplary embodiment, which is a dental restoration, is machined from the blank 28. For this purpose, after knowing the paths of the first region 32 made of the first ceramic material 14 and the second region 34 made of the second ceramic material 20 within the blank 28, the manufactured tooth 42 is virtually arranged within the regions 32, 34 such that the cutting edge is within the first region 32 and the dentin is within the second region 34.

[0079] After the tooth 42 virtually positioned in this way is machined from the blank 28, it can in principle be used immediately, especially if dental prostheses are available that do not require veneers. Monolithic teeth are manufactured. In this case, the machining of the blank is facilitated by the fact that the second region 34 already has the open cavity 26, as explained in connection with FIG. 3 and as can be seen in FIG. 5.

[0080] As can be seen in FIG. 6, there is also a possibility of forming a blank 28 having a number of regions 52, 54, 56, which are made of a second and optionally a third ceramic material and can have different shapes so as to be able to produce corresponding teeth of different shapes. The so-called second regions 52, 54, 56 formed from the second ceramic material 20 are embedded in, i.e., surrounded by, the first ceramic material as can be seen in the drawing.

[0081] There is of course no departure from the present invention if the dental product is machined preferably from a pre-sintered blank before the blank is fully sintered or optionally from a green body, or if important machining is carried out only after the blank has been fully sintered.

[0082] Further embodiments of the teachings according to the present invention result from FIGS. 7 and 8.

[0083] To produce a blank consisting of regions or layers of different compositions in which a continuous transition with respect to the desired properties is achieved between the layers, i.e., for example, when a tooth is produced in which the incisal region is more translucent than the dentin region and the strength of the dentin region is greater than the strength of the incisal region, the die 110 of a press 112 containing a powdery starting material based on zirconium dioxide stabilized with at least gadolinium(III) oxide as the main stabilizer and optionally one or more secondary stabilizers is filled with a first material (layer 114). One or more coloring oxides and / or elements exhibiting fluorescence properties are mixed to the extent necessary. A binder may also be added.

[0084] After filling the die 110 with the first material, the surface is smoothed and structured according to FIG. 7b. For this purpose, in an exemplary embodiment, an element 116 in the form of a disk, plate, or web having a serrated shape on the layer side is used so that a concave structure corresponding to the surface 118 of the layer 114 is formed by shifting the material. This structure appears as concentric ridges and the valleys surrounded by them. The structure should be designed such that the volume of the ridges is equal to or approximately equal to the volume of the depressions or valleys.

[0085] According to FIG. 7c, a layer 124 made of a second material different from the first material is then filled into the die 110 with respect to the content or composition of the stabilizer, or with respect to other components in the case of a stabilizer with a constant content.

[0086] The fact that the material of the second layer 124 penetrates to the bottom of the valleys 126 of the surface 118 of the layer results in a continuous transition between the properties of the layers 114 and 124 after the layers 124 and 114 are pressed according to FIG. 7d. The transition layer is indicated at 128 in FIG. 7d.

[0087] As described, the layer 124 is made of a material different from the layer 114. In particular, in the case of color additives and when one or more elements that generate fluorescence are mixed, there should be a deviation in the proportion.

[0088] Regarding possible deviations in the stabilizer, it should be noted that the second layer 124 should have a lower proportion of the tetragonal crystal phase in the layer 124 than in the layer 114.

[0089] An alternative method for manufacturing a so-called 2D blank, i.e., a blank in which an area that matches the contour of the dental product to be manufactured is not formed as described with reference to FIGS. 2 to 6, and thus the blank can be called a 3D blank, can be seen in FIG. 8.

[0090] A first ceramic material in powder form, which can correspond to the first ceramic material of layer 114 according to FIG. 7, is thus introduced into die 110. The corresponding layer is shown as 214 in FIG. 8a. The height of this layer 214 can be half of the height of all the layers introduced into die 110.

[0091] Next, layer 227 is applied to layer 214, for example, with a thickness of 1 / 10 of the total height of the layer. The material of layer 227 can correspond to the material of the second layer 124 according to FIG. 7. Then, layer 227 is mixed with the surface portion of layer 214 over a depth corresponding to the thickness of layer 227. Thereby, an intermediate layer 228 having a thickness of 2 / 10 of the total height of the layer is formed as shown above. Next, a further layer 224 corresponding to the second layer 124 according to FIG. 7 is applied to the intermediate layer 228.

[0092] Therefore, in an exemplary embodiment, the height of layer 224 is 4 / 10 of the total height H. Thereafter, layers 224, 228, 214 are pressed as a whole to perform the method steps of pre-sintering, machining, and sintering (full sintering) as described. Machining after sintering can of course also be performed.

Claims

1. Zirconium dioxide (ZrO) in tetragonal phase 2 In a blank for use in the manufacture of dental products containing (Gd), such as dental restorations, veneers, or implant components, the zirconium dioxide is provided with gadolinium(III) oxide (Gd) as the main stabilizer. 2 O 3 ) and stabilized with at least one oxide selected from the group comprising Y, Yb, Dy, Nd, Ca, Ce, Mg, Sm, Er, Tb, and La as a secondary stabilizer. The zirconium dioxide is used as the main stabilizer Gd 2 O 3 And, ZrO 2 It is stabilized with a secondary stabilizer in an amount of 0.2 to 0.8 mol% relative to the content of the substance, and the tetragonal phase of zirconium dioxide is present in an amount of 40 to 80 volume percent. The content of the Gd 2 O 3 is 2.5 to 4 mol% with respect to the content of ZrO 2 , characterized by a blank.

2. The blank according to claim 1, characterized in that the blank contains at least one colored oxide from the group consisting of Pr, Er, Fe, Co, Ni, Ti, V, Cr, Cu, Mn, and Tb.

3. The blank according to claim 1 or 2, characterized in that the tetragonal phase of zirconium dioxide is present in an amount of 45 volume% to 75 volume%.

4. The blank according to claim 2, characterized in that the proportion of one or more colored oxides is 1.5% by weight or less in weight percent of the blank.

5. The blank according to claim 1, characterized in that the blank has at least two regions having different compositions, wherein either the total content of the stabilizer and / or the composition of the stabilizer in the regions are different.

6. The blank according to claim 1, characterized in that the blank or region of the blank contains at least one oxide of an element that produces a fluorescence effect, selected from the group Bi, Tb, Tm, and Pr, in a proportion of 0.005 to 2.0% by weight.

7. A first region has a cavity, within which a second region having a different composition from the first region extends, and the first region has a plurality of cavities, within which a plurality of second regions extend. The first region has greater light transmittance than the second region, and the intensity of the second region is greater than the intensity of the first region. A blank according to claim 1, characterized by the following:

8. The blank according to claim 1, wherein the blank has at least three layers, and the intermediate layer between the upper and lower layers contains the materials of the upper and lower layers.

9. The blank according to claim 1, wherein the blank is a multilayer comprising at least one bottom layer and one top layer of different compositions, the layers of the blank contain at least one first colored oxide from the group consisting of Co, Mn, Ni, and Cr, and the proportion of the first colored oxide in the bottom layer is lower than the proportion in the top layer.

10. The main stabilizer Gd 2 O 3 The blank according to claim 1, characterized in that the content ratio of the auxiliary stabilizer to the blank is 1:1 to 1:

120.

11. A method for manufacturing a blank intended for manufacturing a dental product, comprising pressing a powder ceramic material containing zirconium dioxide stabilized with at least one stabilizer, and then subjecting it to at least one heat treatment, wherein the zirconium dioxide is gadolinium(III) oxide (Gd 2 O 3 ) and stabilized with at least one oxide from the group Y, Yb, Dy, Nd, Ca, Ce, Mg, Sm, Er, Tb, La as a secondary stabilizer, the zirconium dioxide contains a tetragonal phase, The aforementioned powdered ceramic material is gadolinium(III) oxide (Gd 2 O 3 ) 2-5 mol%, ZrO 2 A method characterized by containing 0.2-0.8 mol% of the aforementioned auxiliary stabilizer relative to the amount of [the substance], and the amount of the tetragonal phase of zirconium oxide being 40-80 volume%.

12. The method according to claim 11, characterized in that at least one colored oxide from the group consisting of Pr, Er, Fe, Co, Ni, Ti, V, Cr, Cu, Mn, and Tb is added to the ceramic material.

13. The method according to claim 11 or 12, characterized in that a layer of a first ceramic material having a first composition is introduced into a die, at least a first open cavity is formed in the layer and a second ceramic material having a second composition is introduced therein, and the materials are pressed together and then heat-treated, preferably after the second ceramic material has been introduced therein, a second open cavity is introduced and a third ceramic material is introduced therein, the composition of which is different from the composition of the first and / or second ceramic material.

14. The method according to claim 13, characterized in that a first layer of a first ceramic material is introduced into a die, the layer is structured on its surface so as to form ridges and depressions, a second ceramic material is then introduced into the die, and the first layer is at least partially mixed with the second layer so as to form an intermediate layer.

15. A dental product manufactured from a blank according to claim 1 or 2, in the form of a dental restoration, particularly a crown, partial crown, or bridge, or an implant system consisting of an implant and an abutment, A dental product characterized in that the strength of the first layer is greater than the strength of the second layer, and the light transmittance of the second layer is greater than the light transmittance of the first layer.

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