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KR-20260065608-A - Dental glass ceramic molded body

KR20260065608AKR 20260065608 AKR20260065608 AKR 20260065608AKR-20260065608-A

Abstract

The present invention relates to a monolithic glass ceramic molded body for dental restoration comprising an amorphous portion and a crystalline portion, wherein the molded body is characterized in that (a) the weight ratio of the amorphous portion to the crystalline portion changes continuously and gradually, and (b) the weight percentage of zirconium dioxide crystals within the molded body changes continuously and gradually; the molded body comprises lithium disilicate as the main crystalline phase and comprises the following components: i) 56 to 64 wt%, preferably 56 to 59 wt% of SiO₂ ; ii) 15 to 21 wt%, preferably 16 to 20 wt% of Li₂O ; iii) 1 to 4 wt% of K₂O ; iv) 3 to 8 wt% of P₂O₅ ; and v) 8 to 15 wt%, preferably 8 to 12 wt%, particularly 9 to 11 wt% of ZrO₂ .

Inventors

  • 노인, 크리스토퍼

Assignees

  • 비타 찬파브릭 하. 라우터 게엠베하& 코.카게

Dates

Publication Date
20260508
Application Date
20240905
Priority Date
20230905

Claims (14)

  1. A monolithic glass ceramic molded body for dental restoration, comprising an amorphous portion and a crystalline portion, wherein the molded body is characterized by the following: (a) The weight ratio between the amorphous portion and the crystalline portion changes continuously and gradually, and (b) The weight percentage of zirconium dioxide crystals in the molded body changes continuously and gradually, and the molded body comprises lithium disilicate as the main crystalline phase and comprises the following components: i) 56 to 64 weight%, preferably 56 to 59 weight% of SiO2 , ii) 15 to 21 weight%, preferably 16 to 20 weight% of Li₂O , iii) 1 to 4 weight% of K₂O , iv) 3 to 8 weight% of P₂O₅ , and v) 8 to 15 weight%, preferably 8 to 12 weight%, particularly 9 to 11 weight% of ZrO2 .
  2. A glass ceramic molded body according to claim 1, wherein the molded body comprises a compound of elements d and/or f, preferably, the compound of elements d and/or f is selected from the group consisting of oxides of elements d and/or f, and more preferably selected from the group consisting of cerium oxide, terbium oxide, praseodymium oxide, erbium oxide, neodymium oxide, europium oxide, iron oxide, vanadium oxide, manganese oxide, and mixtures thereof.
  3. A glass ceramic molded body according to claim 1 or claim 2, characterized in that the size of the zirconium dioxide crystal grains is 1000 nm or less, preferably 500 nm or less, and preferably the individual ZrO2 crystals are nanocrystals having a size of 200 nm or less.
  4. A glass ceramic molded body characterized in that, in any one or more of claims 1 to 3, the proportion of zirconium dioxide crystals in the molded body is 0.1 to 15 weight%, preferably 0.5 to 10 weight%, more preferably 1 to 8 weight% based on the total weight of the crystals.
  5. A glass ceramic molded body characterized by comprising 0 to 6 weight%, more preferably 0 to 4 weight%, particularly 0.5 to 4 weight% or 1 to 2.5 weight% of CeO2 based on the total weight of the glass ceramic in any one or more of the prior claims.
  6. A glass ceramic molded body characterized in that, in any one or more of the prior claims, lithium disilicate is the main crystalline phase, and said lithium disilicate is included in an amount of 51 to 75 weight%, particularly 52 to 65 weight%, more particularly preferably 53 to 60 weight% based on the total weight of the crystalline phase in said molded body.
  7. A glass ceramic molded body characterized in that, in any one or more of the prior claims, the lithium metasilicate is a secondary crystal phase, and the lithium metasilicate is included in an amount of 20 to 49 weight%, particularly 35 to 48 weight%, more preferably 30 to 47 weight% based on the total weight of the crystal phase in the molded body.
  8. In any one or more of the prior claims, the M z Zr 1-z O 2 exists in a crystalline phase, and a) Preferably, the M z Zr 1-z O 2 is included in an amount of 0.1 to 8 weight%, particularly 0.2 to 6 weight%, more preferably 0.3 to 4 weight% based on the total weight of the crystalline phase in the molded body, and/or b) Preferably, the M z Zr 1-z O 2 has a molar ratio of n(M)/n(Zr) of 0.0001 to 0.6, preferably 0.001 to 0.55, and more preferably 0.04 to 0.4 based on the entire glass ceramic molded body, and A glass ceramic molded body wherein M is a metal selected from existing compounds of the elements d and/or f, preferably the metal is element f, more preferably cerium, and z is preferably a rational number from 0.001 to 0.2.
  9. A method for manufacturing a glass ceramic molded body according to any one or more of claims 1 to 8, comprising the following steps: a) a step of providing a glass ceramic blank capable of forming crystals by heat treatment, b) A first homogeneous heat treatment step, preferably performed at a temperature of preferably 500°C to 600°C to promote nucleation, c) a second homogeneous heat treatment step, performed at a temperature of 580°C to 720°C, which is higher than the temperature of step b), preferably at a temperature of 610°C to 720°C, and preferably to induce pre-crystallization, and d) Preferably, a heterogeneous heat treatment step for forming a gradient of zirconium crystals.
  10. A method according to claim 9, wherein the heterogeneous heat treatment is performed at a temperature T1 in a first region of the blank and at a temperature T2 in a second region of the blank, wherein the temperature difference between T1 and T2 is at least 10°C, preferably at least 20°C, more preferably at least 30°C or at least 40°C or at least 45°C, or greater, and/or preferably T2 is higher than T1.
  11. A method according to at least one of claim 9 or 10, wherein T1 is in the range of 600°C to 750°C, preferably 650°C to 720°C, and/or T2 is in the range of 700°C to 900°C, preferably 740°C to 860°C, and T2 is higher than T1.
  12. A method according to at least one of claims 9 to 11, wherein the heat treatment is performed by inserting the blank into a heating chamber at least partially, preferably through a positive connection, and heating the heating chamber, wherein the temperature inside the heating chamber may optionally be gradually increased through an additional step, and/or the heat treatment is performed by bringing the blank into direct or indirect contact with a heat source, wherein the heat source is preferably a heating plate.
  13. Use for manufacturing a dental restoration of a molded body according to at least one of claims 1 to 8.
  14. A method for manufacturing a dental restoration, comprising the steps of providing a molded body according to at least one of claims 1 to 8 that has undergone at least one heterogeneous heat treatment, and exposing the body to an additional isothermal heat treatment.

Description

Dental glass ceramic molded body The present invention relates to a dental monolithic glass ceramic molded body comprising a continuous gradient of zirconium dioxide, a method for manufacturing the same, and the use of the same for manufacturing dental restorations. Modern dental prosthetic materials must meet high requirements for stability and aesthetics. The balance between effort and quality is a critical factor, as all dental restorations are fabricated individually to fit each patient. During the manufacturing process, reproducing the aesthetic appearance of the tooth is particularly important, as this is directly related to patient comfort. Therefore, restorations must possess a certain level of translucency or opacity depending on their intended use. Furthermore, the materials used must be able to withstand the mechanical and chemical stresses generated during daily food intake. Glass ceramics have established themselves as the standard material for dental restorations by meeting these unique requirements, and their strength and aesthetic properties are particularly highly valued. The crystal structure not only inhibits crack propagation but also reflects and refracts light, unlike ordinary glass. As a result, translucency very similar to natural teeth is achieved, which is why dental glass ceramics are particularly preferred in the aesthetic area of the anterior teeth. WO 2022/179936 A1 discloses a glass ceramic having at least one quartz mixed crystal structure. US 2016/0229742 A1 discloses a lithium silicate glass ceramic that generates surface compressive stress by substituting lithium ions with other alkali metal ions, wherein the preform after ion exchange is used as a molded body. US 2014/0000314 A1 discloses a method for manufacturing a dental restoration by forming a lithium silicate glass ceramic containing zirconium dioxide. WO 2024/013368 A1 discloses a dental glass ceramic molded body, characterized in that lithium metasilicate exists as a dominant crystalline phase within the molded body. EP 2 765 119 discloses a dental blank comprising at least two layers joined together, wherein the layers are made of lithium silicate glass, lithium silicate glass containing a core, or lithium metasilicate glass ceramic, and are of different colors from each other, and the layers form a monolithic structure. Accordingly, it is stated that the optical properties of natural tooth materials can be well mimicked and molded without shrinkage. WO 2013/086187 relates to a lithium silicate glass ceramic comprising 6 to 30 wt% Cs₂O , 55 to 80 wt% SiO₂ , 1 to 5 wt% Al₂O₃ and B₂O₃ , 7 to 16 wt% Li₂O , and 1 to 5 wt% P₂O₅ , wherein each wt% is based on the total weight of the glass ceramic. In particular, it is stated that a block having high transparency can be obtained. EP 2 114 348 discloses a ceramic material composed of yttrium-stabilized zirconium dioxide comprising 58.0-74.0 wt% SiO2 , 4.0-19.0 wt% Al2O3 , 5.0-17.0 wt% Li2O , 4.0-12.0 wt% Na2O , and 0.5-6.0 wt% ZrO2 , which is described as providing high flexural strength and translucency at the same time. Figure 1 shows the crystal structure and size of ZrO2 crystal clusters in the cervical portion of a glass ceramic molded body according to the present invention, recorded using SEM. FIG. 2 shows a ZrO2 cluster according to the present invention having nanocrystalline ZrO2 crystals. FIG. 3 shows the change in crystal structure from the cervical portion (1) to the incisal edge (12) of a glass ceramic molded body according to the present invention, recorded using SEM and XRD. FIG. 4 shows exemplary color measurement results characterized by color coordinates (reflective measurements) and ΔE of different regions (from the incisal edge of plate (1) to the cervical portion of plate (5)) of a glass ceramic molded body according to the present invention. FIG. 5 shows the crystal composition of the crystal phase from the tooth cutting edge (1) to the cervical portion (7) of the glass ceramic molded body according to the present invention, determined by Rietveld analysis, and the color measurement by transmission in the wavelength range of 360 to 750 nm. FIG. 6 shows the crystal phase composition from the tooth cutting edge (1) to the cervical portion (7) of the entire molded body (crystalline phase and glass phase) of the glass ceramic molded body according to the present invention, determined by Rietveld analysis, and the color measurement results by transmission in the wavelength range of 360-750 nm. Figure 7 shows the temperature profile of the method for manufacturing a glass ceramic molded body according to the present invention. Exemplary composition of a glass ceramic molded body according to the present invention. Values are in weight percent: Table 1 shows the measured reflectance values of four glass ceramic molded bodies according to the present invention. This is reflected as a color gradient from the incisal edge to the cervical region and is presen