• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
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    • 专利摘要:
    process for preparing a blank and a blank. the invention relates to a blank for preparing a dental piece such as inlay, onlay, crown or bridge, as well as a process for preparing the blank. so that, from the blank, a dental mold can be made without difficulty, especially with thin resistant walls, it is envisaged that the blank is composed of a ceramic glass material with a density between 30% and 60% of the density theoretical, and glass-ceramic powder particles with a particle size distribution d90 (less than equal) 80 (mi) m, with the content of lithium silicate crystals ranging from 10% by volume to 90% by volume.
    公开号:BR112015027765B1
    申请号:R112015027765-9
    申请日:2014-04-30
    公开日:2020-08-18
    发明作者:Stefan Fecher；Udo Schusser；Martin Kutzner；Heiner Horhold；Markus Vollmann
    申请人:Dentsply International Inc；
    IPC主号:
    专利说明:

    [0001] The invention relates to a blank for preparing a dental impression, such as inlay, onlay, crown or bridge, the blank containing more than 10% by volume of silicate crystals. lithium.
    [0002] In addition, the invention relates to a process for preparing a dental mold, such as inlay, onlay, crown or bridge. The invention also makes reference to a monolithic dental mold.
    [0003] In WO 2012/080513 A1 can be found a process for preparing a porous glass dental mold, which does not have crystalline content. The density of the blank is between 50% and 95% of the theoretical density of a densely sintered part. In this context, monolithic dental molds are prepared from a blank, such as crowns, partial crowns, bridges, inlays or onlays, through dry machining by means of cutters.
    [0004] WO 2011076422 A1 or WO 2012/059143 A1 contains lithium disilicate glass ceramics, which are used for the production of dental molds. The respective glass-ceramic materials must be distinguished by their good mechanical and optical properties.
    [0005] WO 2013/053865 A2 discloses a blank of a lithium silicate glass ceramic material, from which dental molds are produced. The corresponding glass ceramic must contain a trivalent metal oxide of the group Y2O3, La20s, Yb2θ3, BÍ2O3 and mixtures thereof. In addition, the glass ceramic must be essentially free of K2O and Na2O.
    [0006] To prepare a denture based on a lithium disilicate glass-ceramic material, it is also known to prepare cylindrical pellets, and then press them in a muffle (EP 1 484 031 B1).
    [0007] The present invention has the task of preparing a blank from which a dental mold can be made without problems. This means that very thin wall thicknesses must be obtained. The preparation must be able to be carried out through a small wear with the tools. The dental mold prepared from the blank must also be distinguished by good mechanical properties.
    [0008] At least one of the aspects mentioned above, in relation to a blank for preparing a dental mold, such as inlay, onlay, crown or bridge, is solved by the fact that the blank consists of a glass ceramic with a density between 30% and 60% of the theoretical density of the sintered blank and glass-ceramic particles with a grain size distribution dgo 80 pm, in particular a grain size distribution between 10 pm and 60 pm, with the content of crystals of lithium silicate is 10% vol up to 90% vol.
    [0009] A corresponding blank is made by milling, and it has been surprising that the tool wear is small, with tools equipped for example with diamonds not necessary. Sintered dental molds made from a corresponding blank show, in addition, a surprisingly high resistance, and compared to a denture that is processed from a densely sintered blank, there is an increase in strength between 10% and 50%. In particular, there is the possibility of obtaining thin-walled structures, which are not even destroyed by full sintering, since the blanks, due to the content of crystalline phases, have sufficient stability. Here, there is also the advantage of not requiring, in full sintering, supporting support, such as support structures or filling cavities.
    [00010] In particular it is predicted that the crystalline content of the blank is from 30% by vol to 60% by vol. In addition, the blank is distinguished by the fact that it has an open porosity between 50% in vol and 60% in vol, especially between 20% in vol and 50% in vol.
    [00011] Due to the dimensions of the selected parameters, in mechanical elaboration, which occurs particularly dry, it is guaranteed that a sufficiently smooth surface is obtained without, basically after sintering, there is a need for post-processing.
    [00012] Preferably, the glass ceramic powder should have a grain size distribution of 25 pm.
    [00013] By distributing the grain size and pore size from 0.1 pm to 5 pm, a packing density of the powder particles in the blank is produced, so that thin corner structures can be formed without problems. Damaged grains are not visible on the elaborated surfaces.
    [00014] In order to obtain small pore sizes in the range of 0.1 pm to 5 pm, it is particularly expected that the content of finely divided glass particles is correspondingly high.
    [00015] In particular, it is envisaged that the blank has a disc, cube, or shank geometry from which one or more dental molds can be made, to the desired extent and depending on the size of the blank. Thus, for fixing the blank in a milling machine, a means is provided that is disposed on a peripheral surface in a position diametrically opposite the center of gravity of the blank, by means of which the blank can be fixed. Thus, there is the possibility of unscrewing the recesses of the blank, cutouts in which the fixing agents of the processing machine are fixed. Alternatively, they can be inserted glued on the peripheral surface, for example adapters, which are determined to be supported on a machining machine. However, there is still the possibility of making projections on the blank, which serve as support.
    [00016] The invention is particularly distinguished by a blank of glass-ceramic particles with a composition in% by weight of: SiO2 46.0-72.0 Li2O 10.0-25.0 ZrO2 6.5-14 , 0 P2O5 1.0-10.0 AI2O3 0.1-8.0 K2O 0.1-5.0 CeO2 0.1-4.0 B2O3 0.0-4.0 Na2O 0.0-4.0 Tb4O7 0.0-2.5 as well as 0.0 to 4.0 of at least one additive.
    [00017] Preferably the composition of the glass ceramic particles of the blank is in% by weight: SiO2 49.0 - 69.0 Li2O 11.5-24.0 ZrO2 7.0-13.5 P2O5 1.5-9, 0 AI2O3 0.2 - 7.5 K2O 0.2-4.5 CeO2 0.2-3.5 B2O3 0.0-3.5 Na2O 0.0-3.5 Tb4O7 0.0-2.0 so as 0.0 to 4.0 of at least one additive.
    [00018] A composition of glass-ceramic particles for the blank in wt% should be highlighted: SiO2 52.0 -66.0 Li2O 12.0-22.5 ZrO2 7.5-13.0 P2O5 2.0- 8.5 AI2O3 0.3- 7.0 K2O 0.3-4.0 CeO2 0.3- 3.5 B2O3 0.0- 3.0 Na2O 0.0- 3.0 Tb4O7 0.0-2, 0 as well as 0.0 to 4.0 of at least one additive.
    [00019] In addition, a composition of the glass-ceramic particles for the blank in% by weight should be highlighted: SiO2 55.0-63.0 L2O 12.5-21.5 ZrO2 8.0-12.0 P2O5 2.5-8.0 AI2O3 0.4-6.5 K2O 0.4-4.0 CeO2 0.5-3.0 B2O3 0.0-3.0 Na2O 0.0-3.0 Tb4O7 0, 0-2.0 as well as 0.0 to 4.0 of at least one additive.
    [00020] Particularly noteworthy here is a composition of the glass-ceramic particles of the blank, in% by weight: SiO2 58.0-60.0 LI2O 13.5-20.5 ZrO2 8.5-11.5 P2O5 3.0-7.5 AI2O3 0.5-6.0 K2O 0.5-3.5 CeO2 0.5-2.5 B2O3 0.0-3.0 Na2O 0.0-3.0 Tb4O7 0, 0-1.5 as well as 0.0 to 4.0 of at least one additive.
    [00021] At least one additive is at least one additive in the color pigment group, fluorescence agent. In particular, the additive is expected to be at least one oxide of the group BaO, CaO, MgO, MnO, Er2O3, Gd2O3, Pr6011, Sm2O3, TiO2, V2O5, Y2O3 or contains such an oxide.
    [00022] It should be noted that the percentage by weight of the components of the powder mixture in each composition is 100% by weight.
    [00023] The invention is also particularly distinguished by a process for preparing a dental mold, such as inlay, onlay, crown or bridge, comprising the process steps:
    [00024] - Preparation of a melt of a composition in% by weight SiO2 46.0-72.0 Li2O 10.0-25.0 ZrO2 6.5-14.0 P2O5 1.0-10.0 AI2O3 0, 1-8.0 K2O 0.1-5.0 CeO2 0.1-4.0 B2O3 0.0-4.0 Na2O 0.0-4.0 Tb4O7 0.0-2.5 as well as 0.0 up to 4.0 of at least one additive, - preparation of a glass frit by atomising the melt and rapid cooling in a medium, - if appropriate preparation of powdered glass particles from a glass frit with a size distribution of dgo grain 80 pm, - recrystallization of lithium silicate crystals with a volume content between 10% and 90% by first heat treatment or glass frit or powdered glass particles in a first temperature range at a temperature Ti with 500 ° C <Ti <750 ° C for a time ti of 5 min <ti <120 min, - when the glass frit has undergone a heat treatment, the preparation of glass-ceramic particles is carried out with a distribution of dgo grain sizes <80 pm from the fry of vi heat-treated droplet, - pressing of the ceramic glass particles to form a blank, - roughing the part by milling to prepare a dental mold corresponding to the precast considering the contraction behavior of the part and - sintering the precast at a temperature T2 of 800 ° C <T2 <1050 ° C for a time t2 of 5 min <t2 <60 min.
    [00025] According to the invention there is a possibility that either the glass frit or is subjected to a heat treatment to form lithium silicate crystals, without having previously been crushed to obtain powdered glass particles , or the frit is first crushed, and powdered glass particles are also produced, so that the heat treatment can be carried out, so that vitroceramic particles are then present. The characteristic "pressing of glass-ceramic particles to form a blank" therefore includes glass-ceramic particles prepared according to process alternatives.
    [00026] In this case, there is the possibility of carrying out the first heat treatment in two stages within the first temperature range.
    [00027] In particular the melt has a composition in% by weight: SiO2 49.0-69.0 Li2O 11.5-24.0 ZrO2 7.0-13.5 P2O5 1.5-9.0 AI2O3 0, 2 - 7.5 K2O 0.2-4.5 CeO2 0.2 - 3.5 B2O3 0.0-3.5 Na2O 0.0-3.5 Tb4O7 0.0-2.0 as well as 0.0 up to 4.0 of at least one additive.
    [00028] Preferably the melt consists of a composition in% by weight: SiO2 52.0-66.0 LI2O 12.0-22.5 ZrO2 7.5-13.0 P2O5 2.0-8.5 AI2O3 0 , 3-7,0 K2O 0,3-4,0 CeO2 0,3-3,5 B2O3 0,0-3,0 Na2O 0,0-3,0 Tb4O7 0,0-2,0 as well as 0, 0 to 4.0 of at least one additive.
    [00029] Particularly noteworthy is a composition of the melts with a composition in% by weight: SiO2 55.0-63.0 Li2O 12.5-21.5 ZrO2 8.0-12.0 P2O5 2.5-8.0 AI2O3 0.4-6.5 K2O 0.4-4.0 CeO2 0.5-3.0 B2O3 0.0-3.0 Na2O 0.0-3.0 Tb4O7 0.0-2.0 as well as 0.0 to 4.0 of at least one additive.
    [00030] Preferably the melt is expected to have a composition in% by weight: SiO2 58.0-60.0 LI2O 13.5-20.5 ZrO2 8.5-11.5 P2O5 3.0-7.5 AI2O3 0.5-6.0 K2O 0.5-3.5 CeO2 0.5-2.5 B2O3 0.0-3.0 Na2O 0.0-3.0 Tb4O7 0.0-1.5 as well as 0.0 to 4.0 of at least one additive.
    [00031] At least one additive is at least one additive from the group of color pigments, fluorescent agent. In particular, the additive is expected to be at least one oxide from the group of BaO, CaO, MgO, MnO, Er2O3, Gd2O3, Pr6011, Sm2O3, TiO2, V2O5, Y2O3 or that contains such an oxide.
    [00032] According to another advice, it is envisaged that the blank, after a first heat treatment and before mechanical roughing, will be tempered at a temperature of T3 750 ° C T3 900 ° C, for a time of 5 min <ts 30 min
    [00033] Through these relevant heat treatment steps, it is guaranteed that the glass powder, in the quantity required to crystallize lithium crystals, simultaneously produces a small pore size and, therefore, a dense packing of the grain, making it possible to thin out without problems, among others, to reach more delicate areas (filigree).
    [00034] The crystal phase of lithium silicate thus encompasses lithium metasilicate and especially lithium disilicate.
    [00035] It is provided, in particular, that for the preparation of a blank in circular geometry, the glass-ceramic particles are first pressed axially, and then, after being introduced into a wrapper such as an internally coated polyethylene bag, are isostatically post-pressed the post-pressing is carried out especially at a pressure pn of 250 MPa <pn <350 MPa for a time of 4 s 5, 4 s s, in particular 5 s <15 s.
    [00036] For the preparation of a blank in square geometry, the invention provides that the glass-ceramic particles are pressed successively axially and, in particular, continuously with increasing pressure for a period of time ts, the maximum pressure being ps 50 MPa <ps 400 MPa, in particular 100 MPa <ps 200 MPa. The time span in which the pressure increase occurs is 10 s <ts 2 s.
    [00037] For the preparation of a blank in the form of rods, in particular of cylindrical geometry, it is envisaged that the glass ceramic powder is introduced in a form, in the form of rods, in particular of polyurethane, and then is compressed almost isostatically . Therefore, the following compression times and parameters should be especially considered. First, a slow pressure increase is preferred, to distribute the introduced glass ceramic powder evenly. Thereafter the pressure can be quickly raised to its maximum value. After reaching the maximum pressure, it is kept constant during the waiting time. There follows a phase of rapid pressure relief, in which the pressure is reduced to 10% of its maximum value. Complete depressurization then takes place slowly to avoid cracking in the glass ceramic blank.
    [00038] For mechanical roughing, where dry roughing is possible, it is foreseen in particular that a thick roughing first occurs and then a fine roughing (finishing).
    [00039] In rough roughing the cutter parameters are preferred: Cutter diameter: 2 to 5 mm, particularly 2 to 3 mm Feed: 500 to 4000 mm / min, particularly 2000 to 3000 mm / min Lateral pitch ae: 0.2 up to 3 mm, particularly 1 mm to 2 mm Cutting depth ap: 0.1 to 2 mm, particularly 0.5 mm to 1 mm Rotation speed of the cutter: 10,000 to 50,000 1 / min, particularly 10,000 to 20,000 1 / min . Carbide cutters are preferred as cutters.
    [00040] Regarding fine roughing, the following cutter parameters must be considered: Cutter diameter: 0.3 to 1.5 mm, particularly 0.5 to 1.0 mm Feed: 300 to 2000 mm / min, particularly 800 to 1500 mm / min Lateral pitch ae: 0.2 to 0.6 mm, particularly 0.1 mm to 0.2 mm Cutting depth ap: 0.05 to 0.3 mm, particularly 0.1 mm to 0.15 mm Cutter rotation speed: 20,000 to 60,000 1 / min, particularly 25,000 to 35,000 1 / min.
    [00041] Carbide cutters are also preferred here.
    [00042] Particularly good roughing results are then shown when a carbide spherical radius cutter is used as a cutter, with the spherical cutter having to be distinguished below by its cutting angle: Angle of attack / cutting: 0o to -13 °, particularly -9o to -11 ° Free angle: 0o to 15 °, particularly 11 to 13 Wedge angle: results from 90 ° minus the free angle minus the angle of attack / cut
    [00043] If it is not required that, before the compression of the glass ceramic particles, a binder is added, the invention is still not avoided if the corresponding binder, such as cellulose ether, is added with a weight content of up to 5%.
    [00044] In particular, it proved to be advantageous when the blank, therefore its glass-ceramic particles, after compression are immersed in silicic acid or alkaline silicate solution (aqueous glass) and after drying are mechanically ground. As a result, SiO2 bridges are formed between the glass particles, thanks to which the resistance is increased and thus the subsequent mechanical roughing, which includes a CAD / CAM roughing, is facilitated. Through the sintering of the roughed-out molds, free SiO2 is diffused into the glass ceramic, thus increasing the strength.
    [00045] The invention is also distinguished by a monolithic dental mold, which is prepared using a blank according to the invention. In particular, the monolithic dental mold can be a crown or comprise a crown edge with a thickness of DR of 0.05 mm <DR <0.4 mm, in particular 0.1 mm <DR <0.2 mm. The thickness of the crown edge extends from the edge of the end, at a distance of 2 to 4 mm.
    [00046] In addition, the monolithic mold is distinguished by a coefficient of thermal expansion, measured according to ISO 6872, by the fact that it is less than 12.5 x 10-61 / K, preferably between 9.5 x 10'61 / Ke 11.5 x 10 6 1 / K.
    [00047] For pressing ceramic glass particles, a pressure between 50 MPa and 400 MPa, in particular between 100 MPa and 200 MPa, is selected in particular. The temperature in the pre-sintering of the compacted glass powder, therefore of the blank in the form of the compressed glass body, should be in the range 500 ° C and 950 ° C, preferably between 600 ° C and 700 ° C.
    [00048] The external geometry of the compressed glass ceramic body can be in the form of discs or in the form of plates or rods, such as cylindrical, with the geometry of the cross section being freely selected. The volumetric content of the blank can be between 1 cm3 and 160 cm3.
    [00049] After the mechanical roughing of the blank consisting of crystalline porous glass-ceramics, where preferably a milling without cooling, the elaborated dental works are sintered in an appropriate sintering oven under consideration of an appropriate temperature cycle / time cycle . Sintering can be carried out in a temperature range between 700 ° C and 1100 ° C, preferably in the range between 850 ° C and 950 ° C. The total cycle time is less than 2 h, preferably less than 1 h. Due to the crystalline content, it is not necessary for the precast part to be supported. In addition, the precast can, for example, be placed in the sintering furnace on an AI2O3 firing pad.
    [00050] The preferred temperature / time cycle is given: Standby temperature 500 ° C, elevation gradient 50 ° C / min up to 90 ° C / min at 850 up to 900 ° C, wait time 1 up to 5 min, then it cools down slowly. For cooling, the slowest cooling step should preferably be selected.
    [00051] Other particularities, advantages and characteristics of the invention can be deduced not only from the claims and the characteristics that can be deduced from them both by itself or in combination, but also from the following examples of execution.
    [00052] The single figure shows a pressure course over time in the pressing of a blank.
    [00053] To prepare a dental mold, according to the invention, a blank consisting of pressed glass-ceramic powder is used. To make a glass ceramic powder available, first a powder is melted and a glass frit is prepared from the melt, which can have the following preferred compositions: SiO2 49.0-69.0 Li2O 11.5-24.0 ZrO2 7 , 0-13.5 P2O5 1.5-9.0 AI2O3 0.2 - 7.5 K2O 0.2-4.5 CeO2 0.2 - 3.5 B2O3 0.0-3.5 Na2O 0.0 -3.5 Tb4O7 0.0-2.0 as well as 0.0 to 4.0 of at least one additive.
    [00054] In particular, the molten glass is expected to have a composition in% by weight: SiO2 49.0-69.0 Li2O 11.5-24.0 ZrO2 7.0-13.5 P2O5 1.5-9, 0 AI2O3 0.2-7.5 K2O 0.2-4.5 CeO2 0.2-3.5 B2O3 0.0-3.5 Na2O 0.0-3.5 Tb4O7 0.0-2.0 so as 0.0 to 4.0 of at least one additive.
    [00055] Preferably the molten glass consists of a composition in% by weight: SiO2 52.0-66.0 Li2O 12.0-22.5 ZrO2 7.5-13.0 P2O5 2.0-8.5 AI2O3 0.3- 7.0 K2O 0.3-4.0 CeO2 0.3-3.5 B2O3 0.0-3.0 Na2O 0.0-3.0 Tb4O7 0.0-2.0 as well as 0 , 0 to 4.0 of at least one additive.
    [00056] Particular emphasis should be given to a composition of molten glass with a composition by weight: SiO2 55.0 -63.0 Li2O 12.5-21.5 ZrO2 8.0-12.0 P2O5 2.5-8 , 0 AI2O3 0.4- 6.5 K2O 0.4- 4.0 CeO2 0.5- 3.0 B2O3 0.0- 3.0 Na2O 0.0- 3.0 Tb4O7 0.0-2.0 as well as 0.0 to 4.0 of at least one additive.
    [00057] It should preferably be provided that the molten glass has a composition in% by weight: SiO2 58.0 -60.0 LI2O 13.5-20.5 ZrO2 8.5-11.5 P2O5 3.0-7, 5 AI2O3 0.5- 6.0 K2O 0.5- 3.5 CeO2 0.5- 2.5 B2O3 0.0- 3.0 Na2O 0.0- 3.0 Tb4O7 0.0-1.5 as well as 0.0 to 4.0 of at least one additive.
    [00058] At least one additive is an additive of at least the color pigment group, fluorescence agent. In particular, it is envisaged that the additive is at least one oxide of the group BaO, CaO, MgO, MnO, Er2O3, Gd2O3, Pr6011, Sm2O3, TiO2, V2O5, Y2O3 or contains such an oxide.
    [00059] The corresponding mixture of starting materials, for example in the form of oxides and carbonates, is then melted in a suitable crucible of fire-resistant material or noble metal alloy at a temperature between 1350 ° C and 1600 ° C for a time interval between 1 h to 10 h, in particular over a period of 4 h to 7 h at a temperature of 1540 ° C. At the same time or subsequently homogenization, for example by stirring. The liquid glass thus prepared is then preferably guided into a tipping nozzle, which is preferably set at a temperature in the range between 1250 ° C and 1450 ° C, in particular 1310 ° C. The nozzle can have a diameter between 1 mm and 2 mm. The oscillation frequency of the nozzle can be between 40 Hz and 60 Hz, in particular in the 50 Hz range. The liquid glass is then abruptly cooled in a suitable medium as a fluid, such as water or a high temperature cushion. The tempered glass frit thus prepared is then dried. Then crushing takes place, for example, in a ball mill. Sieving takes place, where a sieve with a mesh size between 50 pm and 500 pm can be used. If necessary, further crushing can take place, for example by means of a jet mill or a friction mill.
    [00060] Of the glass powders and glass particle powders thus prepared, those that correspond to a grain size distribution dgo 80 pm, in particular 10 pm <dõo 60 pm, are selected in particular. dgo or dso means that 90% or 50% of the particles present have a diameter smaller than the given value or are in that range.
    [00061] In order that the blank can be worked without problems, without the molded part prepared from the blank being unstable at full sintering, or the frit obtained after casting or pre-crushed or powdered powder are subjected to a crystallization step. Here, in a first heat treatment stage, the frit or powder is subjected to a temperature Ti between 500 ° C and 750 ° C for a time ti between 5 minutes and 120 minutes. The first heat treatment stage can also take place in two stages, that is, the first heat treatment stage at 640 ° C, preferably 660 ° C for 60 minutes and 750 ° C for 40 minutes.
    [00062] Preferably, then, another heat treatment in the form of tempering takes place, with the selected T3 temperature should be between 750 ° C and 900 ° C. The tempering step is carried out for a time interval ts in particular between 5 minutes and 30 minutes.
    [00063] And then the glass ceramic particles are pressed, where appropriate pressing processes are employed, depending on the geometry to be prepared, in particular an axial or isostatic pressing or combinations thereof. The compression occurs here in such a range that the density of the blank corresponds to 30% to 60% of the theoretical density of the blank material of approximately 2.64 g / cm3. In particular, the blank should have a density of approximately 50% of the theoretical density.
    [00064] For pressing the glass ceramic powder, it is preferably subjected to a pressure between 50 MPa and 400 MPA, in particular between 100 MPa and 200 MPa.
    [00065] The single figure shows as an example a pressure curve over time during the pressing of a blank. In a first phase P1, the pressure is increased from zero with a pressure gradient of, for example, 15 MPa / s to a pressure of, for example, 30 MPa. In a second phase P2, the pressure is raised from 30 MPa with a pressure gradient of 100 MPa / s to a pressure of approximately 200 MPa. In a third phase P3, the pressure is kept constant at a value of approximately 200 MPa for a maintenance time of approximately 10 seconds. In a fourth phase, a pressure reduction occurs preferably in two stages, where in a P4a phase the pressure is reduced from approximately 200 MPa to approximately 20 MPa with a pressure gradient of 40 MPa / s, and in a P4b phase the pressure is reduced from 20 MPa to 0 MPa gauge with a pressure gradient of approximately 10 MPa / s.
    [00066] After pressing, mechanical milling takes place, where roughing and then finishing can occur. Treatment can take place without cooling. Dry treatment is possible.
    [00067] During roughing, the following milling parameters should be observed: Cutter diameter: 2 to 5 mm, in particular 2 to 3 mm Feed: 500 to 4000 mm / min, in particular 2000 to 3000 mm / min Side step ae : 0.2 to 3 mm, in particular 1 mm to 2 mm Cutting depth ap: 0.1 to 2 mm, in particular 0.5 mm to 1 mm Rotation speed of the cutter: 10,000 to 50,000 1 / min, in 10,000 to 20,000 1 / min.
    [00068] The milling tool should be a carbide mill in particular.
    [00069] The cutter parameters for finishing should be: Cutter diameter: 0.3 to 1.5 mm, in particular 0.5 to 1.0 mm Feed: 300 to 2000 mm / min, in particular 800 to 1500 mm / min Side pitch ae: 0.2 to 0.6 mm, in particular 0.1 mm to 0.2 mm Adjustment of cutting depth ap: 0.05 to 0.3 mm, in particular 0.1 mm to 0.15 mm Cutter rotation speed: 20,000 to 60,000 1 / min, in particular 25,000 to 35,000 1 / min.
    [00070] The milling tool should be a carbide mill in particular.
    [00071] A carbide ball radius cutter is preferably used, which can be coated with titanium nitride. Here, the following cutting angles should be preferred: Cutting angle: 0o to -13o, in particular -9o to -11 ° Free angle: 0o to 15 °, in particular 11o to 13 ° Wedge angle: is given by 90 ° less free angle less cutting angle
    [00072] Thanks to the density of the blank and the crystalline portion, dental molds with delicate (filigree) edges can be prepared without problems. In the case of crowns, it has been shown that thicknesses of stable edges between 0.05 mm and 0.4 mm are formed.
    [00073] After processing, the dental mold prepared from the blank must be called a pre-molded piece, considering that this, in comparison with the fully sintered dental mold, presents a super dimension in what corresponds to the contraction of the blank material. Depending on the density of the blank, oversizing is calculated in order to provide a high-precision dental prosthesis as a final product after full sintering.
    [00074] Sintering and dense sintering occur at a temperature T2 between 800 ° C and 1050 ° C over a waiting time of between 5 min and 60 min. Waiting time here means that the blank is kept at the desired final sintering temperature.
    [00075] When sintering, the pre-molded mold is placed on a fire-resistant support such as a thermal pad or on crust-free metal layers. Supporting structures are not necessary since, based on the crystallization of the starting powder, the stability of the mold is guaranteed.
    [00076] Other characteristics of the invention emerge from the following examples, the parameters given having meaning in themselves and not necessarily in combination: 1. Preparation of a disk-shaped blank
    [00077] A quantity of 230 g of glass ceramic powder containing pre-crystallized lithium silicate crystal with the composition in% by weight: SiO2 58 - 60 Li2O 13,5-20,5 ZrO2 8,5-11,5 P2O5 3, 0-7.5 AI2O3 0.5-6.0 K2O 0.5-3.5 CeO2 0.5-2.5 B2O3 0 - 3 Na2O 0 - 3 Tb4O7 0-1.5 as well as 0 to 4 of hair minus one additive, with a grain size distribution of dso = 18.7 pm, are pre-pressed with a pressure of 50 MPa using a 105 mm diameter tool with a hydraulic press. Then the press is placed in a coated polyethylene bag, evacuated and water-tight welded. In a water / oil emulsion the pressed is post-pressed at 290 MPa for 10 seconds isostatically. After unpacking, heat treatment and light sintering at 650 ° C occur. The density of the blank is 1.88 g / cm3.
    [00078] The final geometry of the blank is prepared by a return to an outside diameter of 98.5 mm. For insertion into a milling machine, the front sides of each part are rotated.
    [00079] Dental molds with corresponding sintering dimensions are nested on the surface of the blank with a circular geometry. For crowns such as dental molds they have a very good fine crown edge and an exceptional milling surface.
    [00080] The sintering takes place in a dental curing oven on the AI2O3 firing pad with a stepped sintering program over a total time of 60 minutes. Step sintering program means that at least two different waiting times are foreseen, during which the respective temperature is kept constant. The maximum sintering temperature was 950 ° C, which was maintained for 10 minutes. The subsequent evaluation of the crowns resulted in an aesthetic appearance with a good dental fit. 2. Preparation of a cube-shaped blank
    [00081] A quantity of 9.6 g of pre-crystallized glass-ceramic powder of composition in% by weight: SiO2 58 - 60 LI2O 13.5-20.5 ZrO2 8.5-11.5 P2O5 3.0-7, 5 AI2O3 0.5-6.0 K2O 0.5-3.5 CeO2 0.5-2.5 B2O3 0 - 3 Na20 0 - 3 Tb4O7 0-1.5 as well as 0 to 4 of at least one additive, with a grain size distribution of dso = 21.3 pm it is axially compressed with continuously rising pressure to 120 MPa with a hydraulic press in a carbide mold and under an appropriate load of preferably 5 MPa again unmolded. The obtained press has a dimension of 20.2 x 19.1 x 15.9 mm and a density of 1.56 g / cm3. Then the press is subjected to a heat treatment in two stages in an elevator oven at 630 ° C and 700 ° C. The density of the blank increased after the heat treatment to 1.75 g / cm3.
    [00082] To be fastened to a machining machine, a mushroom-shaped adapter is glued to the narrow side of the blank. The roughing of the dental crown, increased to compensate for the contraction in the sintering, took place by means of a special quick cutter for a noticeably shorter milling time with a milling feed of up to 2000 mm / minute. This made it possible to visibly shorten the milling time compared to the part prepared in example 1. The crown had a smooth outer side and the crown edge was free of breakage. The sintering took place on an AI2O3 firing pad in a dental curing oven with a stepwise cycle for a total time of 65 minutes and a maximum sintering temperature of 950 ° C for 10 minutes. A subsequent evaluation of the crown resulted in an aesthetic color with a good dental fit. 3. Preparation of a rod-shaped blank
    [00083] A quantity of 210 g of pre-crystallized glass-ceramic powder of composition in% by weight: SiO2 58 - 60 LI2O 13.5-20.5 ZrO2 8.5-11.5 P2O5 3.0-7.5 AI2O3 0.5-6.0 K2O 0.5-3.5 CeO2 0.5-2.5 B2O3 0 - 3 Na2O 0 - 3 Tb4O7 0-1.5 as well as 0 to 4 of at least one additive, with a grain size distribution of dso = 19.1 pm is compressed with a Wet-Bag press at an almost isostatic pressure of 195 MPa to form a tube-shaped polyurethane tool. After deformation there is a heat treatment for additional crystallization at 620 ° C and preinterinter at 680 ° C. The final geometry of the blank is prepared by re-routing up to an outside diameter of 25 mm and a length of 198 mm. The density of the blank is 1.81 g / cm3.
    [00084] Dental crowns with a corresponding sintering dimension are milled from the stem-shaped glass-ceramic blanks on the front side. The crowns have a narrow, break-free crown edge and a good milling surface. Sintering takes place in small dental chamber curing ovens on small shelves with AI2O3 firing pads. A sintering program is employed with a total cycle time of 45 minutes. Maximum heat treatment temperature 980 ° C. At this temperature, the blank was kept for 5 minutes. Ready-made crowns have an aesthetic appearance with a good dental fit.
    权利要求:
    Claims (12)
    [0001]
    1. Process for preparing a dental mold such as inlay, onlay, crown or bridge, characterized by the fact that it comprises the steps of: (a) preparing a melt of the composition in% by weight: SiO2 46.0 to 72, 0 LI2O 10.0 to 25.0 ZrO2 6.5 to 14.0 P2O5 1.0 to 10.0 AI2O3 0.1 to 8.0 K2O 0.1 to 5.0 CeÜ2 0.1 to 4.0 B2O3 0.0 to 4.0 Na2Ü 0.0 to 4.0 Tb4O7 0.0 to 2.5 as well as 0.0 to 4.0 of at least one additive, (b) preparation of a glass frit by spraying the melt and sudden cooling in a medium, (c) if necessary, formation of glass dust particles from a glass frit with a grain size distribution dgo 80 pm, (d) recrystallization of lithium silicate crystals with a content volume between 10% and 90% by means of a first heat treatment of the glass frit or powdered glass particles in a first temperature range at a temperature Ti of 500 ° C <Ti <750 ° C for a time ti 5 minutes <ti <120 minutes, (e) and then, when the glass fries is subjected to a heat treatment, from the heat treated glass frit the production of glass-ceramic particles with a grain size distribution d90 80 pm occurs, (f) compression of the glass-ceramic particles to form a blank with a density between 30% and 60% of the theoretical density of the blank of 2.64 g / cm3, (g) elaboration of the blank by milling to prepare a dental mold from the respective pre-mold considering the shrinking behavior of the blank and (h) sintering the preform at a T2 temperature of 800 ° C <T2 1050 ° C for a time of 22 with 5 min <22 ^ 60 min.
    [0002]
    2. Process according to claim 1, characterized by the fact that a melt of the composition is prepared in% by weight: SiO2 49.0 to 69.0 Li2O 11.5 to 24.0 ZrO2 7.0 to 13, 5 P2O5 1.5 to 9.0 AI2O3 0.2 to 7.5 K2O 0.2 to 4.5 CeO2 0.2 to 3.5 B2O3 0.0 to 3.5 Na2Ü 0.0 to 3.5 Tb4O7 0.0 to 2.0 as well as 0.0 to 4.0 of at least one additive.
    [0003]
    3. Process according to claim 1, characterized by the fact that a melt of the composition is prepared in% by weight: SiO2 Li2O ZrO2 P2O5 52.0 to 66.0 12.0 to 22.5 7.5 to 13 , 0 2.0 to 8.5 Al2θ3 0.3 to 7.0 K2O 0.3 to 4.0 CeO2 0.3 to 3.5 B2O3 0.0 to 3.0 Na2O 0.0 to 3.0 Tb4O7 0.0 to 2.0 as well as 0.0 to 4.0 of at least one additive.
    [0004]
    4. Process according to claim 1, characterized by the fact that a melt of the composition is prepared in% by weight: SiO2 55.0 to 63.0 Li2O 12.5 to 21.5 ZrO2 8.0 to 12, 0 P2OÕ 2.5 to 8.0 AI2O3 0.4 to 6.5 K2O 0.4 to 4.0 CeO2 0.5 to 3.0 B2O3 0.0 to 3.0 Na2O 0.0 to 3.0 Tb4O7 0.0 to 2.0 as well as 0.0 to 4.0 of at least one additive.
    [0005]
    5. Process according to claim 1, characterized by the fact that a melt of the composition is prepared in% by weight: SiO2 58 to 60 Li2O 13.5 to 20.5 ZrO2 8.5 to 11.5 P2O5 3, 0 to 7.5 AI2O3 0.5 to 6.0 K2O 0.5 to 3.5 Ceθ2 0.5 to 2.5 B2O3 0 to 3 Na2O 0 to 3 Tb4O7 0 to 1.5 as well as 0.0 to 4 , 0 of at least one additive.
    [0006]
    Process according to any one of claims 1 to 5, characterized by the fact that the blank before elaboration and after the first heat treatment is tempered at a temperature T3 with 750 ° C <900 ° C for a time ts 5 minutes <ts 30 minutes.
    [0007]
    7. Process according to any one of claims 1 to 6, characterized in that for the preparation of a blank in the geometric shape of discs, the glass-ceramic particles are first pressed axially and then, after being inserted into a wrapper , like a bag lined with polyethylene, are isostatically redensified, the redensification being carried out especially at a pressure pn of 250 MPa <pn 350 MPa for a time t4 of 5 seconds <t4 <30 seconds, in particular 5 seconds <t4 <15 seconds.
    [0008]
    Process according to any one of claims 1 to 6, characterized in that for preparing a blank in the geometric shape of a cube, the glass ceramic particles are successively compressed in particular with increasing pressure over a period of time ts axially, the maximum pressure ps being 50 MPa <ps 400MPa, in particular 100 MPa <ps 200 MPa.
    [0009]
    Process according to any one of claims 1 to 6, characterized in that for the preparation of a blank in particular in the cylindrical geometric shape, the ceramic glass powder is introduced in a press form in the tubular form, in particular of polyurethane, and then almost isostatically.
    [0010]
    10. Process according to any one of claims 1 to 9, characterized by the fact that the blank is made by milling at least roughly and then is machined with precision, being considered preferred cutter parameters for the rough milling: Cutter diameter: 2 to 5 mm, in particular 2 to 3 mm Feed: 500 to 4000 mm / min, in particular 2000 to 3000 mm / min Lateral pitch ae: 0.2 to 3 mm, in particular 1 mm up to 2 mm Penetration depth ap: 0.1 to 2 mm, in particular 0.5 mm to 1 mm Rotation speed of the cutter: 10,000 to 50,0001 / min, in particular 10,000 to 20,0001 / min and / or the milling parameters for fine finishing, preference is given to: Cutter diameter: 0.3 to 1.5 mm, in particular 0.5 to 1.0 mm Feed: 300 to 2000 mm / min, in particular 800 to 1500 mm / min lateral ae: 0.2 to 0.6 mm, in particular 0.1 mm to 0.2 mm Penetration depth ap: 0.05 to 0.3 mm, in particular 0.1 mm to 0.15 mm Speed d and milling speed: 20,000 to 60,0001 / min, in particular 25,000 to 35,0001 / min.
    [0011]
    11. Process according to any one of claims 1 to 10, characterized in that the cutter with a spherical radius is used as the cutter with the following cutting angles: orthogonal cutting angle: 0 ° to -13 °, in particular - 9o to -11 ° free angle: 0o to 15 °, in particular 11o to 13 ° wedge angle: it is 90 ° minus the free angle minus the orthogonal cutting angle.
    [0012]
    12. Process according to any one of claims 1 to 10, characterized in that the blank is immersed in silicic acid or alkaline silicate solution (soluble glass), dried and then is made dry by machining or The part is prepared in the rough by machining and then, before sintering at the final density, it is immersed in silicic acid or alkaline silicate solution (soluble glass) and is dried.
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    同族专利:
    公开号 | 公开日
    CN105377216B|2018-08-31|
    ES2770505T3|2020-07-01|
    RU2696587C2|2019-08-05|
    WO2014177659A1|2014-11-06|
    CA2911284C|2019-07-23|
    AU2014261405B2|2018-11-15|
    US20160113845A1|2016-04-28|
    DE102013104561A1|2014-11-06|
    CN105377216A|2016-03-02|
    EP2991610A1|2016-03-09|
    EP3124010A1|2017-02-01|
    JP6542200B2|2019-07-10|
    AU2014261405A1|2015-11-26|
    CA2911284A1|2014-11-06|
    KR102055112B1|2019-12-13|
    JP2016522779A|2016-08-04|
    US9737465B2|2017-08-22|
    EP2991610B1|2019-12-18|
    KR20160010865A|2016-01-28|
    RU2015151586A|2017-06-08|
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    法律状态:
    2018-01-23| B07D| Technical examination (opinion) related to article 229 of industrial property law|
    2018-02-27| B06F| Objections, documents and/or translations needed after an examination request according art. 34 industrial property law|
    2018-05-15| B07B| Technical examination (opinion): publication cancelled|
    2019-07-30| B06U| Preliminary requirement: requests with searches performed by other patent offices: suspension of the patent application procedure|
    2020-04-07| B09A| Decision: intention to grant|
    2020-08-18| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 30/04/2014, OBSERVADAS AS CONDICOES LEGAIS. |
    优先权:
    申请号 | 申请日 | 专利标题
    DE102013104561.8|2013-05-03|
    DE201310104561|DE102013104561A1|2013-05-03|2013-05-03|Process for the production of a blank and blank|
    PCT/EP2014/058920|WO2014177659A1|2013-05-03|2014-04-30|Process for producing a blank, and a blank|
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