Glass ceramics containing a quartz mixed crystalline phase

Abstract

Quartz solid solution glass ceramics and their precursors are described, which are characterized by very good mechanical and optical properties and can be used as restorative materials, especially in dentistry. The invention is based on the problem of providing glass ceramics that have a high strength and good translucency in combination. The glass ceramics should also have a thermal expansion coefficient that can be adjusted over a wide range. The glass ceramics should also be easy to process into dental restorative materials and therefore suitable in an excellent manner as restorative dental materials.

Description

[Technical Field]

[0001] The present invention relates to glass ceramics containing a quartz solid solution phase, which are particularly suitable for use in dentistry, preferably for the manufacture of dental restorative materials, and to precursors for the manufacture of these glass ceramics. [Background technology]

[0002] Glass ceramics containing a quartz solid solution phase are basically known from the prior art.

[0003] DE2507131A1 describes a special magnesium aluminosilicate glass ceramic containing 20-35 wt% Al2O3 and 9-15 wt% MgO. The substrate made from this glass ceramic has a heterogeneous structure in which the crystal structure of the surface layer differs from the crystal structure inside the substrate. The resulting surface compressive stress has a very significant impact on the mechanical properties; therefore, machining of the surface layer can lead to a decrease in mechanical properties. A high-temperature quartz solid solution was detected in the surface layer, while a low-temperature quartz solid solution was detected inside the substrate.

[0004] JP2000 / 063144A discloses magnesium aluminosilicate glass for the preparation of a substrate for a storage medium containing 30-60 mol% SiO2 and a large amount of B2O3.

[0005] GB2172282A describes a magnesium aluminosilicate glass ceramic containing 10-40 wt% Al2O3. The glass ceramic is intended for microelectronic applications, particularly as a coating on substrates such as aluminum, and in addition to its high strength, it has a suitable dielectric constant in the range of 7-10 and high electrical resistance.

[0006] WO2012 / 143137A1 describes a glass ceramic substrate containing at least 10.1% by weight of Al2O3 and having different crystalline phases in different regions.

[0007] In the paper by M. Dittmer and C. Russel, J. Biomed. Mater. Res. Part B: 100B: 463-470 (2012), there is described a glass-ceramic containing a high-temperature quartz or low-temperature quartz solid solution phase as the main crystalline phase and containing at least 25.9 wt% of Al2O3. Generally, the strength achieved by these known glass-ceramics and also their optical properties are not entirely satisfactory for dental material applications.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Means for Solving the Problems

[0009] Therefore, the present invention is based on the problem of providing a glass-ceramic having a combination of high strength and good translucency. The glass-ceramic should also have a coefficient of thermal expansion that can be adjusted over a wide range. The glass-ceramic should also be easy to process into dental restorative materials and thus be suitable in an excellent manner as a restorative dental material.

[0010] This problem is solved by the glass-ceramics containing a quartz solid solution phase according to claims 1 to 16 and 19. Also, the subject matter of the present invention is the starting glass according to claims 17 to 19, the process according to claims 20 and 23, and the use according to claims 21 and 22. In embodiments of the present invention, for example, the following items are provided. (Item 1) The following ingredients Table 11 A glass ceramic comprising a solid solution of at least one quartz phase. (Item 2) A glass ceramic as described in item 1, comprising at least two different quartz solid solution phases. (Item 3) The glass ceramic according to item 1 or 2, comprising at least one, preferably at least two, stoichiometric or non-stoichiometric aluminosilicate crystalline phases, particularly preferably at least one, preferably at least two non-stoichiometric aluminosilicate crystalline phases. (Item 4) 57.0 to 66.5%, preferably 59.0 to 66.0%, and particularly preferably 62.1 to 65.5% by weight of SiO 2 Glass ceramics, including any one of items 1-3. (Item 5) Li in a weight of 13.3-18.0, preferably 16.1-17.5, and especially preferably 16.5-17.0%. 2 Glass ceramics, including O, as described in any one of items 1-4. (Item 6) 0.5 to 1.7, preferably 1.1 to 1.5, and especially preferably 1.2 to 1.4% by weight of K 2 Glass ceramics, including O, as described in any one of items 1-5. (Item 7) 2.0 to 3.8%, preferably 1.6 to 3.6% by weight of Al 2 O 3 Glass ceramics, including any one of items 1 through 6. (Item 8) P in a weight of 4.3-6.0, preferably 4.5-5.9, and particularly preferably 5.1-5.8%. 2 O 5 Glass ceramics, including any one of items 1 through 7. (Item 9) 7.2 to 13.0, preferably 9.0 to 12.0 wt% ZrO 2 Glass ceramics, including any one of items 1 through 8. (Item 10) 1.0 to 8.0, preferably 1.0 to 5.5, and especially preferably 1.5 to 2.5% by weight of Na 2 O, Rb 2 O, Cs 2 Monovalent element oxides Me selected from the group consisting of O and mixtures thereof I 2 Glass ceramics, including O, as described in any one of items 1 through 9. (Item 11) 0.05-5.0, particularly 0.07-1.5, preferably 0.08-1.0, especially preferably 0.09-0.4, most preferably 0.1-0.2 wt%, of a divalent element oxide Me selected from the group consisting of CaO, MgO, SrO, ZnO and mixtures thereof. II O is included, and the Me II A glass ceramic according to any one of items 1 to 10, wherein O is preferably MgO. (Item 12) 0-5.0, preferably 1.0-4.0, particularly preferably 2.0-3.0% by weight, B 2 O 3 、Y 2 O 3La 2 O 3 , Ga 2 O 3 In 2 O 3 and trivalent element oxides Me selected from the group of mixtures thereof III 2 O 3 Glass ceramics, including any one of items 1 through 11. (Item 13) SiO2 in a molar ratio in the range of 1.5 to 6.0, particularly 1.55 to 3.0, preferably 1.6 to 1.8, and especially preferably 1.65 to 1.75. 2 and Li 2 Glass ceramics, including O, as described in any one of items 1 to 12. (Item 14) A glass ceramic according to any one of items 1 to 13, wherein the main crystalline phase is lithium disilicate or lithium metasilicate, preferably containing lithium disilicate as the main crystalline phase. (Item 15) A glass ceramic according to any one of items 1 to 14, comprising at least 20% by weight, preferably 25 to 55% by weight, and particularly preferably 30 to 55% by weight of lithium disilicate crystals. (Item 16) A glass ceramic according to any one of items 1 to 15, comprising 0.2 to 28% by weight, preferably 0.2 to 25% by weight, of a quartz solid solution. (Item 17) Starting glass containing the glass-ceramic components described in any one of items 1 through 13. (Item 18) The starting glass according to item 17, comprising nuclei for crystallization of a quartz solid solution phase, preferably also comprising nuclei for crystallization of lithium disilicate or lithium metasilicate. (Item 19) The glass ceramic and the starting glass are in the form of a powder, granules, blank or dental restorative material, as described in any one of items 1 to 16 or as the starting glass described in item 17 or 18. (Item 20) A process for producing glass ceramics according to any one of items 1 to 16, comprising subjecting a starting glass according to item 17 or 18, particularly in the form of fine particles, preferably in the form of powder, particularly preferably in the form of a powder molded body, to at least one heat treatment in the range of 600 to 1000°C, preferably 650 to 900°C, particularly sintering. (Item 21) Preferably, use of a glass ceramic as described in any one of items 1 to 16 or 19, or a starting glass as described in any one of items 17 to 19, as a dental material for coating a dental restorative material, and particularly preferably for manufacturing a dental restorative material. (Item 22) Use for manufacturing the dental restorative material described in item 21, wherein the glass ceramic or the starting glass is given the shape of a desired dental restorative material, in particular a bridge, inlay, onlay, veneer, abutment, partial crown, crown or facet, by pressing or machining. (Item 23) A process for manufacturing dental restorative materials, in particular bridges, inlays, onlays, veneers, abutments, partial crowns, crowns or facets, wherein a glass ceramic as described in any one of items 1-16 or 19, or a starting glass as described in any one of items 17-19, is given the shape of a desired dental restorative material by pressing or machining. [Modes for carrying out the invention]

[0011] The glass ceramic according to the present invention has the following components [Table 2] It is characterized by containing and containing at least one quartz solid solution phase.

[0012] This glass ceramic, also referred to hereafter as "glass ceramic containing a quartz solid solution phase" in this specification, surprisingly exhibits a favorable combination of mechanical and optical properties desirable for restorative dental materials. While possessing high strength, the glass ceramic can be easily molded into the shape of a dental restorative material by pressing or machining. Furthermore, the inclusion of one or more quartz solid solution phases unexpectedly resulted in remarkably good optical properties. This is because many secondary crystalline phases have a negative effect on the optical properties of glass ceramics. For example, they can reduce translucency and impair the possibility of imparting color to the glass ceramic, making it considerably difficult to mimic the color of the natural dental material being replaced.

[0013] Furthermore, it was shown that the thermal expansion coefficient of the glass ceramic according to the present invention can vary over a wide range depending on the type and amount of the quartz solid solution phase formed. Finally, it was also found that the glass ceramic according to the present invention can be densely sintered at higher temperatures compared to lithium silicate-quartz glass ceramic without losing their shape.

[0014] The term "quartz solid solution phase" refers to a crystalline phase of SiO2 in which foreign atoms are incorporated into the SiO2 lattice either at interstitial or lattice positions. These foreign atoms may be, in particular, Al, as well as Li, Mg, and / or Zn. Al may be present in a molar concentration corresponding to the sum of the molar concentrations of Li, twice the molar concentration of Mg, and twice the molar concentration of Zn.

[0015] In a preferred embodiment, the glass ceramic contains at least two different quartz solid solution phases.

[0016] At least one quartz solid solution phase may be either stoichiometric or non-stoichiometric. A stoichiometric quartz solid solution phase means a crystalline phase in which the number of silicon atoms and the number of one of the foreign atoms are in the ratio x:y (where x and y are integers in the range of 1 to 8, particularly 1 to 5). In a preferred embodiment, the glass ceramic contains at least one, preferably at least two, non-stoichiometric quartz solid solution phases.

[0017] At least one of the quartz solid solution phases may be a stoichiometric or non-stoichiometric aluminosilicate crystalline phase. In a preferred embodiment, the glass ceramic contains at least one, preferably at least two, stoichiometric or non-stoichiometric aluminosilicate crystalline phases. In a particularly preferred embodiment, the glass ceramic contains at least one, preferably at least two, non-stoichiometric aluminosilicate crystalline phases. In this context, a stoichiometric aluminosilicate crystalline phase is understood to be a crystalline phase in which the number of silicon atoms and the number of aluminum atoms are in the ratio x:y (where x and y are integers in the range of 1 to 8, particularly 1 to 5). Examples of stoichiometric aluminosilicate crystalline phases include eucryptite (LiAlSiO4), spodumene (LiAlSi2O6), and petalite (LiAlSi4O6). 10 ) and cordierite (Mg2Al4Si5O 18 )

[0018] The quartz solid solution phase of the glass ceramic according to the present invention is particularly Cu Kα It can be detected by X-ray powder diffraction using irradiation. The quartz solid solution phase exhibits a characteristic peak pattern, each of which originates from the peak pattern of low-temperature quartz but shifts to a different 2Θ value.

[0019] The glass ceramic containing the quartz solid solution phase according to the present invention contains 57.0 to 66.5%, preferably 59.0 to 66.0%, and especially preferably 62.1 to 65.5% by weight of SiO2.

[0020] The glass ceramic according to the present invention preferably further contains Li2O in an amount of 13.3 to 18.0, preferably 16.1 to 17.5, particularly preferably 16.5 to 17.0% by weight. It is assumed that Li2O reduces the viscosity of the glass matrix and thus promotes the crystallization of the desired phase.

[0021] Moreover, the glass ceramic preferably contains K2O in an amount of 0.5 to 1.7, preferably 1.1 to 1.5, particularly preferably 1.2 to 1.4% by weight.

[0022] In a preferred embodiment, the glass ceramic according to the present invention contains Al2O3 in an amount of 2.0 to 3.8, preferably 1.6 to 3.6% by weight.

[0023] In another preferred embodiment, the glass ceramic contains P2O5 in an amount of 4.3 to 6.0, preferably 4.5 to 5.9, particularly preferably 5.1 to 5.8% by weight. P2O5 is assumed to act as a nucleating agent.

[0024] The glass ceramic more preferably contains ZrO2 in an amount of 7.2 to 13.0, preferably 9.0 to 12.0% by weight.

[0025] Moreover, the glass ceramic contains an oxide Me2O of a monovalent element selected from the group consisting of Na2O, Rb2O, Cs2O, and mixtures thereof in an amount of 1.0 to 8.0, preferably 1.0 to 5.5, particularly preferably 1.5 to 2.5% by weight. I 2O.

[0026] Particularly preferably, the glass ceramic contains at least one, particularly all, of the following oxides Me2O of monovalent elements in the indicated amounts: I 2O: [Table 3]

[0027] The glass ceramic according to the present invention preferably contains 0.05 to 5.0, particularly 0.07 to 1.5, preferably 0.08 to 1.0, more preferably 0.09 to 0.4, and most preferably 0.1 to 0.2 by weight of a divalent element oxide Me selected from the group consisting of CaO, MgO, SrO, ZnO and mixtures thereof. II It contains O, Me II O is preferably MgO. Divalent element oxide Me II O, and especially MgO, is thought to promote the formation of one or more quartz solid solution phases, thus avoiding the formation of undesirable crystalline phases, particularly cristobalite, which can have detrimental effects on the coefficient of thermal expansion and optical properties.

[0028] In another preferred embodiment, the glass ceramic contains less than 2.0% by weight of BaO. In particular, the glass ceramic is substantially BaO-free.

[0029] Preferably, the glass ceramic is an oxide of the following divalent element Me II Contains at least one, and especially all, of the following O in the indicated amounts: [Table 4]

[0030] 0-5.0, preferably 1.0-4.0, and particularly preferably 2.0-3.0 wt% of trivalent element oxides Me selected from the group consisting of B2O3, Y2O3, La2O3, Ga2O3, In2O3 and mixtures thereof. III Glass ceramics containing 2O3 are even more preferred.

[0031] Particularly preferred is the glass ceramic having the following trivalent element oxides Me III Contains at least one, and especially all, of the 2O3 species in the indicated amounts: [Table 5]

[0032] Furthermore, 0 to 10.0, particularly preferably 0 to 8.0 wt%, of tetravalent element oxides selected from the group consisting of TiO2, SnO2, CeO2, GeO2 and mixtures thereof, are added. IV Glass ceramics containing O2 are preferred.

[0033] Particularly preferred is the glass ceramic having the following tetravalent element oxides Me IV Contains at least one, and especially all, of the following types of O2 in the indicated amounts: [Table 6]

[0034] In another embodiment, the glass ceramic contains 0 to 8.0, preferably 0 to 6.0 wt% of a pentavalent element oxide Me selected from the group consisting of V2O5, Ta2O5, Nb2O5 and mixtures thereof. V It contains 2O5.

[0035] Particularly preferred is the glass ceramic having the following pentavalent element oxides Me V Contains at least one, and especially all, of the 2O5 species in the indicated amounts: [Table 7]

[0036] In another embodiment, the glass ceramic contains 0 to 5.0, preferably 0 to 4.0 wt% of a hexavalent element oxide Me selected from the group consisting of WO3, MoO3, and mixtures thereof. VI O 3 It contains.

[0037] Particularly preferred is the glass ceramic, which is the following oxide Me VI Contains at least one, and especially all, of the O3 species in the indicated amounts: [Table 8]

[0038] In further embodiments, the glass ceramic according to the present invention contains 0 to 1.0, particularly 0 to 0.5% by weight of fluorine.

[0039] Glass ceramics containing at least one, preferably all, of the following components in the indicated amounts are particularly preferred: [Table 9] In the table, Me I 20, Me II O, Me III 203, Me IV O2, Me V 2O5 and Me VI O3 is defined as described above.

[0040] In another specific preferred embodiment, the glass ceramic comprises at least one, preferably all, of the following components in the indicated amounts: [Table 10]

[0041] Some of the above components can serve as colorants and / or fluorescent agents. The glass ceramic according to the present invention may further contain additional colorants and / or fluorescent agents. These may be selected, for example, from Bi2O3 or Bi2O5, and in particular from additional inorganic pigments and / or oxides of elements d and f, such as oxides of Mn, Fe, Co, Pr, Nd, Tb, Er, Dy, Eu, and Yb. These colorants and fluorescent agents make it possible to easily color the glass ceramic to mimic the desired optical properties of, in particular, natural tooth material. It is remarkable that this is easily possible despite the presence of one or more quartz solid solution phases.

[0042] In preferred embodiments of the glass ceramic, the molar ratio of SiO2 to Li2O is in the range of 1.5 to 6.0, particularly 1.55 to 3.0, preferably 1.6 to 1.8, and especially preferably 1.65 to 1.75. Surprisingly, the preparation of the quartz solid solution phase glass ceramic of the present invention is possible within this wide range.

[0043] The glass ceramic according to the present invention is even more preferably to contain lithium disilicate or lithium metasilicate as a further crystalline phase, particularly as the main crystalline phase.

[0044] The term "principal crystalline phase" refers to the crystalline phase that has the highest weight fraction of all crystalline phases present in the glass ceramic. The amount of the crystalline phase is determined, in particular, by the Rietveld method. A suitable procedure for the quantitative analysis of the crystalline phase by the Rietveld method is described, for example, in the academic paper "Glaser und Glaskeramiken im System MgO-Al2O3-SiO2mit ZrO2als Keimbildner" by M. Dittmer, University of Jena 2011.

[0045] The glass ceramic according to the present invention preferably contains at least 20% by weight, preferably 25 to 55% by weight, and particularly preferably 30 to 55% by weight of lithium disilicate crystals.

[0046] The glass ceramic according to the present invention more preferably contains 0.2 to 28% by weight, preferably 0.2 to 25% by weight, of a quartz solid solution.

[0047] The glass ceramic containing the quartz solid solution phase according to the present invention is characterized in particularly good mechanical and optical properties and can be formed by heat treatment of the corresponding starting glass or a starting glass having the corresponding nucleus. Therefore, these materials can serve as precursors for the glass ceramic containing the quartz solid solution phase according to the present invention.

[0048] The type and, in particular, the amount of crystalline phase formed can be controlled by the composition of the starting glass, as well as by the heat treatment applied to produce the glass ceramic from the starting glass. The examples illustrate this by varying the composition of the starting glass and the heat treatment applied.

[0049] The glass ceramic has a high biaxial fracture strength, preferably at least 200 MPa, and particularly preferably 250-460 MPa. The biaxial fracture strength was determined according to ISO 6872 (2008) (piston-on-three-balls test).

[0050] The glass ceramic according to the present invention is particularly 3.0 to 14.0.10 -6 K -1 Preferably 5.0-14.0·10 -6 K -1 Particularly preferred is 7.0 to 14.0.10 -6 K -1 It has a coefficient of thermal expansion CTE (measured in the range of 100 to 500°C). The CTE was determined according to ISO 6872 (2008). Adjustment of the coefficient of thermal expansion to a desired value is performed in particular by the type and amount of crystalline phase present in the glass ceramic, as well as by the chemical composition of the glass ceramic.

[0051] The translucency of the glass ceramic was determined with respect to the contrast value (CR value) according to British standard BS 5612, and this contrast value was preferably between 40 and 92.

[0052] Due to a specific combination of the properties of glass ceramics according to the present invention, glass ceramics can even be used as dental materials, particularly as materials for preparing dental restorative materials.

[0053] The present invention also relates to precursors of corresponding compositions that can be used to produce glass ceramics containing a quartz solid solution phase according to the present invention by heat treatment. These precursors are correspondingly composed starting glass and starting glass having correspondingly composed nuclei. The term "corresponding composition" means that these precursors contain the same components in the same amounts as the glass ceramic, and the components are calculated as oxides, as is typical for glass and glass ceramics, with the exception of fluorine.

[0054] Therefore, the present invention also relates to a starting glass containing components of a glass ceramic according to the present invention, which includes a quartz solid solution phase.

[0055] Therefore, the starting glass according to the present invention contains particularly suitable amounts of SiO2, Li2O, K2O, Al2O3, P2O5, and ZrO2, which are necessary for forming the glass ceramic containing the quartz solid solution phase according to the present invention. Furthermore, the starting glass may also contain other components as shown above for the glass ceramic containing the quartz solid solution phase according to the present invention. All such embodiments are preferred for the components of the glass ceramic containing the quartz solid solution phase according to the present invention and for the components of the starting glass indicated as preferred.

[0056] Particularly preferred is the starting glass in the form of powder, granules, or a powder molded body pressed from powder or granules. In contrast to glass monoliths, such as those obtained by pouring molten glass into a mold, the starting glass of the above form has a large inner surface where subsequent crystallization of one, preferably several, quartz solid solution phases can occur. This may have the advantage of requiring fewer heat treatment steps to form one or more quartz solid solution phases compared to the crystallization of glass monoliths.

[0057] The present invention also relates to such starting glass containing nuclei for the crystallization of a quartz solid solution phase. Preferably, the starting glass also contains nuclei for the crystallization of lithium disilicate or lithium metasilicate.

[0058] The starting glass is produced by melting a mixture of particularly suitable starting materials, such as carbonate and oxide, at a temperature of approximately 1500-1700°C for 0.5-4 hours. To achieve particularly high homogeneity, the resulting glass molten material can be poured into water to form glass frit, which is then remelted.

[0059] The molten material is then poured into a mold, for example, a steel or graphite mold, to produce a blank of starting glass, a so-called solid glass blank or monolithic blank. Typically, these monolithic blanks are first stress-relieved by holding them at 800–1200°C for 5–60 minutes, and then slowly cooled to room temperature.

[0060] In a preferred embodiment, the molten material is poured into water to produce a frit. This glass frit can be processed into a powder or granules by grinding. Preferably, the powder or granules thus obtained can be pressed, after the addition of further components such as colorants and fluorescent agents as needed, to form a blank, a so-called powder molded body. By using powders of several different colors, a multicolor blank having several areas with different color characteristics can be obtained in a simple manner. Thus, the present invention enables the production of highly aesthetic multicolor dental restorative materials that can particularly well mimic the optical properties of natural tooth materials.

[0061] A further precursor starting glass containing a nucleus can be produced by heat treatment of the starting glass. Subsequently, the glass ceramic containing the quartz solid solution phase according to the present invention can be produced by heat treatment of this further precursor. Alternatively, the glass ceramic containing the quartz solid solution phase according to the present invention can be formed by heat treatment of the starting glass.

[0062] It is preferable to heat-treat the starting glass at a temperature of 400 to 600°C, particularly 450 to 550°C, for a period of 5 to 120 minutes, preferably 10 to 60 minutes, to produce a starting glass having nuclei for the crystallization of the quartz solid solution phase.

[0063] It is even more preferable to produce a glass ceramic containing a quartz solid solution phase by subjecting the starting glass or starting glass with a nucleus to at least one heat treatment at a temperature of 600 to 1000°C, preferably 650 to 900°C, particularly preferably 750 to 900°C, for a period of 1 to 240 minutes, preferably 5 to 120 minutes, and particularly preferably 10 to 60 minutes. In a particularly preferred embodiment, the starting glass or starting glass with a nucleus is subjected to a first heat treatment at a temperature of 600 to 800°C, preferably 650 to 750°C, particularly preferably 650 to 700°C, for a period of 1 to 120 minutes, preferably 5 to 120 minutes, and particularly preferably 10 to 60 minutes, and then to a second heat treatment at a temperature of 750 to 950°C, preferably 800 to 900°C, particularly preferably 800 to 850°C, for a period of 1 to 120 minutes, preferably 5 to 120 minutes, and particularly preferably 10 to 60 minutes.

[0064] Accordingly, the present invention also relates to a process for producing glass ceramics comprising a quartz solid solution phase according to the present invention, particularly comprising subjecting a starting glass or nucleus having a starting glass or nucleus in the form of fine particles, preferably in the form of powder, particularly preferably in the form of a powder molded body, to at least one heat treatment at a temperature in the range of 600 to 1000°C, preferably 650 to 900°C, for a time particularly of 1 to 240 minutes, preferably 5 to 120 minutes, particularly preferably 10 to 60 minutes, particularly sintering.

[0065] At least one heat treatment performed in the process according to the present invention may also be performed in the process of hot pressing or sintering the starting glass according to the present invention or the starting glass having a nucleus according to the present invention.

[0066] The glass ceramics and glass according to the present invention exist, in particular, as powders, granules, or blanks of any shape and size, such as plates, cubes, or cylinders, e.g., monolithic blanks, or powder molded bodies. In these forms, they can be easily processed further into, for example, dental restorative materials. However, they can also be in the form of dental restorative materials, e.g., inlays, onlays, crowns, veneers, facets, or abutments.

[0067] Particularly preferable is the glass ceramic according to the present invention in the form of a multicolor blank, and more particularly in the form of a multicolor pre-sintered or sintered powder molded body.

[0068] Dental restorative materials, such as bridges, inlays, onlays, crowns, veneers, facets, or abutments, can be manufactured from glass ceramics and glass according to the present invention. Therefore, the present invention also relates to their use in the manufacture of dental restorative materials, particularly multi-color dental restorative materials. It is preferable that the glass ceramic or glass be given the desired shape of the dental restorative material by pressing or machining.

[0069] Pressing is typically carried out under high pressure and high temperature. Pressing is preferably carried out at a temperature of 700-1200°C. Pressing is even more preferably carried out at a pressure of 2-10 bar. During pressing, the desired change in shape is achieved by the viscous flow of the material used. Starting glass according to the present invention, starting glass having a nucleus according to the present invention, and glass ceramics containing a quartz solid solution phase according to the present invention can be used for pressing. In particular, the glass and glass ceramics according to the present invention can be used in the form of blanks of any shape and size, for example, in unsintered, partially sintered, or densely sintered forms, for example, in the form of powder molded bodies.

[0070] Machining is typically carried out by material removal processes, particularly by milling and / or grinding. Machining is particularly preferably carried out using a CAD / CAM process. The starting glass according to the present invention, the starting glass having a nucleus according to the present invention, and the glass ceramics comprising a quartz solid solution phase according to the present invention can be used for machining. The glass and glass ceramics according to the present invention can be used in particular in the form of blanks, for example, unsintered, partially sintered, or densely sintered forms, for example, in the form of powder molded bodies.

[0071] For example, after a dental restorative material has been manufactured by pressing or machining to form the desired shape, it can be further heat-treated, for example, to reduce the porosity of the porous powder molded body used.

[0072] However, the glass ceramics and glass ceramics according to the present invention are also suitable as coating materials for ceramics and glass ceramics, for example. Therefore, the present invention also applies to the use of the glass or glass ceramics according to the present invention, particularly for coating ceramics and glass ceramics.

[0073] The present invention also relates to a process for coating ceramics, metals, metal alloys and glass ceramics, wherein the glass ceramic or glass according to the present invention is applied to a corresponding substrate and subjected to a high temperature.

[0074] This can be done, in particular, by sintering an overlay manufactured by CAD-CAM, or by joining it with a suitable glass solder or adhesive and preferably by pressing. When sintering, the glass ceramic or glass is applied in a conventional manner, for example, as a powder, to the material to be coated, such as ceramic or glass ceramic, and then sintered at a high temperature. In preferred pressing, the glass ceramic or glass according to the present invention, for example in the form of a powder molded body, is pressed at a high temperature, for example, 700 to 1200°C, while applying a pressure, for example, 2 to 10 bar. In particular, the process described in EP231773 and the press furnace disclosed therein can be used for this purpose. A preferred furnace is, for example, the Programat EP 5000 made by Ivoclar Vivadent AG, Liechtenstein.

[0075] Due to the above-described properties of the glass ceramics and glass according to the present invention, they are particularly suitable for use in dentistry. Therefore, a further subject of the present invention is the use of the glass ceramics or glass according to the present invention as dental materials, preferably for coating dental restorative materials, and particularly preferably for manufacturing dental restorative materials such as bridges, inlays, onlays, veneers, abutments, partial crowns, crowns, or facets.

[0076] Accordingly, the present invention also relates to a process for manufacturing dental restorative materials, in particular bridges, inlays, onlays, veneers, abutments, partial crowns, crowns, or facets, wherein the process imparts the desired shape of the dental restorative material to a glass ceramic or glass according to the present invention, particularly by pressing or machining, in a CAD / CAM process. Multicolor dental restorative materials are preferred. Such restorations can particularly well mimic the optical properties of natural tooth material.

[0077] The present invention will be described in more detail below by non-limiting examples. [Examples]

[0078] (Examples 1-9) Composition and crystalline phase A total of nine types of glass and glass ceramics according to the present invention, having the compositions shown in Table I, were produced by melting the corresponding starting glass and subsequently heat-treating it for controlled crystallization.

[0079] The heat treatments applied are also shown in Table I. The following meanings apply. T g Glass transition temperature determined by DSC T Kb and t Kb Temperature and time applied for nucleation of the starting glass T C and t C Temperature and time applied for crystallization

[0080] For this purpose, the starting glass was first melted from conventional raw materials in a platinum-rhodium crucible at 1500-1700°C.

[0081] In Examples 1-3, glass monoliths were produced by pouring molten starting glass into graphite or steel molds. These glass monoliths were then stress-released and slowly cooled to room temperature. They were then subjected to a nucleation temperature T Kb time t Kb A first heat treatment over a certain period, followed by a temperature T for crystallization. C time t C It was subjected to another heat treatment.

[0082] In Examples 4-9, glass frit, or glass granules, were produced by pouring molten starting glass into water. The glass frit was ground to a particle size of <45 μm using a ball or mortar mill and pressed into a powder molded body using a powder molding press. The powder molded body was subjected to a temperature T for nucleation and crystallization, as needed. Kb time t Kb Heat treatment over a period of time, temperature T C1 time tC1 A first heat treatment over a certain period, and at a temperature T C2 time t C2 It was subjected to a second heat treatment.

[0083] The meaning in Table I below: QMK: quartz solid solution phase SP: Spodumene (LiAlSi2O6) [Table 1-1] [Table 1-2] [Table 1-3]

Claims

1. The following ingredients Table 11 A glass ceramic comprising a quartz solid solution phase, wherein the quartz solid solution phase refers to a crystalline phase of SiO₂ in which foreign atoms are incorporated into the SiO₂ lattice either at interstitial or lattice positions, and the foreign atoms comprise at least one of Al, Li, Mg, and Zn.

2. The glass ceramic according to claim 1, comprising at least two different quartz solid solution phases.

3. The glass ceramic according to claim 1 or 2, comprising at least one, preferably at least two, stoichiometric or non-stoichiometric aluminosilicate crystalline phases, particularly preferably at least one, preferably at least two non-stoichiometric aluminosilicate crystalline phases.

4. 57.0 to 66.5, preferably 59.0 to 66.0, and particularly preferably 62.1 to 65.5% by weight of SiO ２ A glass ceramic according to any one of claims 1 to 3, including the glass ceramic.

5. 13.3 to 18.0, preferably 16.1 to 17.5, particularly preferably 16.5 to 17.0% by weight of Li ２ A glass ceramic according to any one of claims 1 to 4, comprising O.

6. 0.5 to 1.7, preferably 1.1 to 1.5, and particularly preferably 1.2 to 1.4% by weight of K ２ A glass ceramic according to any one of claims 1 to 5, comprising O.

7. 2.0 to 3.8%, preferably 1.6 to 3.6% by weight of Al ２ O ３ A glass ceramic according to any one of claims 1 to 6, including the glass ceramic.

8. 4.3 to 6.0, preferably 4.5 to 5.9, and particularly preferably 5.1 to 5.8% by weight of P ２ O ５ A glass ceramic according to any one of claims 1 to 7, including the glass ceramic.

9. 7.2 to 13.0, preferably 9.0 to 12.0% by weight of ZrO ２ A glass ceramic according to any one of claims 1 to 8, including the glass ceramic.

10. 1.0 to 8.0, preferably 1.0 to 5.5, particularly preferably 1.5 to 2.5% by weight of Na ２ O, Rb ２ O, Cs ２ O and oxides Me of monovalent elements selected from the group consisting of mixtures thereof Ｉ ２ O, the glass ceramic according to any one of claims 1 to 9.

11. A glass ceramic according to any one of claims 1 to 10, comprising 0.07 to 1.5, preferably 0.08 to 1.0, particularly preferably 0.09 to 0.4, and most preferably 0.1 to 0.2% by weight of MgO.

12. 0 to 5.0, preferably 1.0 to 4.0, particularly preferably 2.0 to 3.0% by weight of B ２ O ３ , Y ２ O ３ La ２ O ３ Ga ２ O ３ In ２ O ３ and trivalent element oxides Me selected from the group of mixtures thereof ＩＩＩ ２ O ３ A glass ceramic according to any one of claims 1 to 11, including the glass ceramic.

13. The molar ratio of SiO₂ to Li₂O is in the range of 1.5 to 6.0, particularly 1.55 to 3.0, preferably 1.6 to 1.8, and especially preferably 1.65 to 1.

75. ２ and Li ２ A glass ceramic according to any one of claims 1 to 12, comprising O.

14. A glass ceramic according to any one of claims 1 to 13, wherein lithium disilicate or lithium metasilicate, preferably lithium disilicate, is the main crystalline phase.

15. A glass ceramic according to any one of claims 1 to 14, comprising at least 20% by weight, preferably 25 to 55% by weight, and particularly preferably 30 to 55% by weight of lithium disilicate crystals.

16. A glass ceramic according to any one of claims 1 to 15, comprising 0.2 to 28% by weight, preferably 0.2 to 25% by weight, of a quartz solid solution.

17. A starting glass comprising the glass ceramic component described in any one of claims 1 to 13.

18. The starting glass according to claim 17, comprising nuclei for crystallization of a quartz solid solution phase, preferably also comprising nuclei for crystallization of lithium disilicate or lithium metasilicate.

19. The glass ceramic according to any one of claims 1 to 16 or the starting glass according to claim 17 or 18, wherein the glass ceramic and the starting glass are in the form of a powder, granules, blank or dental restorative material.

20. A process for producing a glass ceramic according to any one of claims 1 to 16, comprising subjecting a starting glass according to claim 17 or 18, particularly in the form of fine particles, preferably in the form of a powder, and especially preferably in the form of a powder molded body, to at least one heat treatment in the range of 600 to 1000°C, preferably 650 to 900°C, particularly sintering.

21. Preferably, the use of a glass ceramic according to any one of claims 1 to 16 or 19, or a starting glass according to any one of claims 17 to 19, as a dental material for coating a dental restorative material, and particularly preferably for manufacturing a dental restorative material.

22. Use for manufacturing the dental restorative material according to claim 21, wherein the glass ceramic or the starting glass is given the shape of a desired dental restorative material, in particular a bridge, inlay, onlay, veneer, abutment, partial crown, crown or facet, by pressing or machining.

23. A process for manufacturing dental restorative materials, in particular bridges, inlays, onlays, veneers, abutments, partial crowns, crowns or facets, wherein a glass ceramic according to any one of claims 1 to 16 or 19, or a starting glass according to any one of claims 17 to 19, is given the shape of a desired dental restorative material by pressing or machining.

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