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WO2025051863A1 - Corps moulé en vitrocéramique à usage dentaire - Google Patents

Corps moulé en vitrocéramique à usage dentaire Download PDF

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Publication number
WO2025051863A1
WO2025051863A1 PCT/EP2024/074841 EP2024074841W WO2025051863A1 WO 2025051863 A1 WO2025051863 A1 WO 2025051863A1 EP 2024074841 W EP2024074841 W EP 2024074841W WO 2025051863 A1 WO2025051863 A1 WO 2025051863A1
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Prior art keywords
shaped body
glass
weight
ceramic
temperature
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PCT/EP2024/074841
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German (de)
English (en)
Inventor
Christopher NEUN
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Vita Zahnfabrik H Rauter GmbH and Co KG
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Vita Zahnfabrik H Rauter GmbH and Co KG
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Publication of WO2025051863A1 publication Critical patent/WO2025051863A1/fr
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Classifications

    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C10/00—Devitrified glass ceramics, i.e. glass ceramics having a crystalline phase dispersed in a glassy phase and constituting at least 50% by weight of the total composition
    • C03C10/0009—Devitrified glass ceramics, i.e. glass ceramics having a crystalline phase dispersed in a glassy phase and constituting at least 50% by weight of the total composition containing silica as main constituent
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
    • C03C3/097—Glass compositions containing silica with 40% to 90% silica, by weight containing phosphorus, niobium or tantalum

Definitions

  • the present invention relates to a monolithic glass-ceramic shaped body for dental purposes, which contains a continuous gradient of zirconium dioxide, a process for its production, and the use for the production of dental restorations.
  • glass ceramics Due to this specific requirement profile, glass ceramics have become a common material for dental restorations, with their strength and aesthetic properties being particularly valued.
  • the crystalline component not only prevents the spread of cracks but also reflects and deflects light differently than with traditional glass. This creates a translucency very similar to that of natural teeth, which is why dental glass ceramics are used particularly in the aesthetic zone of the anterior teeth.
  • WO 2022/179936 A1 describes a glass ceramic with at least one quartz solid solution structure.
  • US 2016/0229742 A1 describes a lithium silicate glass ceramic in which a surface compressive stress is generated by exchanging lithium ions for other alkali metal ions, whereby the preform body is used as a molded body after the exchange of the ions.
  • US 2014/0000314 A1 describes a method for producing a dental restoration by molding a lithium silicate glass ceramic containing zirconium dioxide.
  • WO 2024/013368 A1 describes a glass-ceramic molded body for dental purposes, wherein lithium metasilicate is present as the dominant crystal phase in the molded body.
  • EP 2765119 describes a blank for dental purposes comprising at least two interconnected layers of lithium silicate glass, lithium silicate glass with nuclei, or lithium metasilicate glass-ceramic, wherein the layers differ in color and are monolithic. This should make it possible to closely mimic the optical properties of natural tooth material and achieve a shape without shrinkage.
  • WO 2013/086187 relates to a lithium silicate glass-ceramic containing 6 to 30 wt.% CS2O, 55 to 80 wt.% SiO2, 1 to 5 wt.% Al2O3 and B2O3, 7 to 16 wt.% U2O, and 1 to 5 wt.% P2O5, with the wt.% values referring to the total weight of the glass-ceramic.
  • This composition is said to enable the production of blocks with high transparency.
  • EP 2114348 describes a ceramic material made of yttrium-stabilized zirconium dioxide, which contains SiO2 58.0-74.0 wt.%, Al2O3 4.0-19.0 wt.%, U2O 5.0-17.0 wt.%, Na2O 4.0-12.0 wt.% and ZrO2 0.5-6.0 wt.%, which thereby achieves a high flexural strength with simultaneous translucency.
  • the object underlying the present invention is achieved by providing a monolithic glass-ceramic shaped body for dental restorations, comprising an amorphous portion and a crystalline portion, characterized in that the shaped body
  • (b) contains a continuously and gradually changing percentage by weight of zirconium dioxide crystals in the shaped body, wherein the shaped body has lithium disilicate as the main crystal phase and the shaped body has the following components: i) from 56 to 64 wt.%, preferably from 56 to 59 wt.% SiO2, ii) from 13 to 21 wt.%, preferably from 16 to 20 wt.%, U2O, iii) from 1 to 4 wt.% K2O, iv) from 3 to 8 wt.% P2O5 and v) from 8 to 15 wt.%, preferably from 8 to 12 wt.%, in particular from 9 to 11 wt.% ZrO2.
  • the monolithic glass-ceramic molded body has a crystalline portion with zirconium dioxide and crystals, with lithium disilicate being the main component of the crystal phase.
  • Main constituent of the crystal phase within the meaning of the present invention means that the crystal proportion in wt.% is the highest compared to the other crystals with a different chemical composition in the shaped body.
  • the main constituent makes up more than 30 wt.%, particularly preferably more than 40 wt.%, and in particular more than 50 wt.%, in each case based on the total weight of all crystals.
  • lithium disilicate is present in a higher weight proportion than lithium metasilicate.
  • the weight ratio of lithium disilicate to lithium metasilicate is preferably greater than 1:1, in particular greater than 1.1:1 or greater than 1.2:1.
  • the other crystals can preferably be selected from the group consisting of lithium metasilicate, lithium phosphate, lithium aluminum oxide, spodumene, virgilite, keatite, SiO2 polymorphs, o-quartz, ⁇ -quartz, o-tridymite, ⁇ -tridymite, o-cristobalite, ⁇ -cristobalite, and mixtures thereof.
  • the shaped body according to the invention can have lithium metasilicate and disilicate as dominant crystal phases. Dominant crystal phases are those crystal phases that are present in the highest weight fractions.
  • the shaped body is preferably free of spodumene and/or virgilite, wherein their proportion in the shaped body is preferably less than 1 wt. %, particularly preferably less than 0.5 wt. %, in particular less than 0.1 wt. %, and especially less than 0.01 wt. %, in each case based on the total weight of the shaped body.
  • the monolithic glass-ceramic shaped body according to the invention further comprises silicon dioxide, lithium oxide, potassium oxide, diphosphorus pentoxide and zirconium dioxide, the following amounts preferably being included in the shaped body according to the invention: i) from 56 to 64% by weight, preferably from 56 to 59% by weight of SiO2, ii) from 13 to 21% by weight, preferably from 16 to 20% by weight, U2O, iii) from 1 to 4% by weight of K2O, iv) from 3 to 8% by weight of P2O5 and v) from 8 to 15% by weight, preferably from 8 to 12% by weight, in particular from 9 to 11% by weight of ZrO2.
  • the monolithic glass-ceramic molded body according to the invention comprises aluminum oxide, preferably in an amount of 0.1 to 10 wt. %, more preferably 0.5 to 8 wt. %, and most preferably 1 to 4 wt. %, each based on the total weight of the molded body. This contributes to the stability of the glass-ceramic molded body.
  • the monolithic glass-ceramic molded bodies according to the invention contain at least one compound containing a d- and/or f-element, preferably its oxide, and/or mixtures thereof. Furthermore, the monolithic glass-ceramic molded body according to the invention can preferably contain inorganic and/or organic coloring components. These substances can be amorphous and/or crystalline.
  • the monolithic glass-ceramic shaped body according to the invention comprises a) from 56 to 64% by weight, preferably from 56 to 59% by weight of SiO2, b) from 13 to 21% by weight, preferably from 16 to 20% by weight, U2O, c) K2O from 1 to 4% by weight, d) P2O5 from 3 to 8% by weight, e) Al2O3 from 0 to 10% by weight, preferably from 1 to 4% by weight, f) from 8 to 15% by weight, preferably from 8 to 12% by weight, in particular from 9 to 11% by weight of ZrO2, g) at least one oxide of a d- or f-element of the Periodic Table of the Elements, preferably a compound of the structure MxOy , from 0 to 8% by weight, preferably from 0.1 to 7% by weight, particularly preferably from 1 to 4% by weight ; and h) optionally inorganic and/or organic coloring components, wherein the
  • the value of x is selected from the natural numbers 1-10, preferably from the numbers 1-5. Furthermore, it is possible to select the value of x based on y, which is determined via the oxidation state of the d or f element.
  • the oxidation states of the d or f elements are usually selected from (+1), (+11), (+III), (+IV), (+V), (+VI), (VII) or (VIII) and, depending on the compound, are known to the person skilled in the art.
  • Y can take on the natural numbers 1-10.
  • the d-elements of component g) are not zirconium and preferably not yttrium and/or hafnium.
  • components g) and h) are selected so that they are different substances, preferably chemically different.
  • the monolithic glass-ceramic molded body according to the invention is used for dental purposes, i.e., in particular for the restoration of individual teeth, full dentures of the upper and/or lower jaw, dental bridges, locator dentures, and/or dental crowns.
  • Other dental purposes are familiar to the person skilled in the art, so the application of the glass-ceramic molded body is not limited to these.
  • the monolithic glass-ceramic molded body according to the invention has an amorphous and a crystalline portion.
  • the amorphous portion is characterized by the fact that the atoms of the chemical compounds therein are not arranged in an ordered structure, but are irregularly arranged.
  • amorphous material is characterized by the fact that the structure only has short-range order, but no long-range order, and behaves isotropic.
  • crystalline means that the atoms in the chemical compounds have an ordered structure with both short-range and long-range order and produce discrete reflections in the X-ray diffraction pattern that can be assigned to the individual structures. This presence of both amorphous and crystalline portions can also be referred to as semi-crystalline to describe the property of this invention.
  • the weight ratio of the amorphous and crystalline fractions as well as the composition of the crystal phases can be determined by Rietveld analysis using AI2O3 as internal standard.
  • the gradients according to the invention in the monolithic glass-ceramic molded body are reflected in particular in a color and translucency gradient.
  • a natural tooth has a color gradient that follows a gradient from the gums to the cutting edge or chewing surface.
  • the gradient follows an axis that runs through the molded body.
  • the gradient runs perpendicular to the longest dimension of the molded body, preferably 90° to its longitudinal axis.
  • the gradient runs along the longest dimension of the molded body, preferably parallel to its longitudinal axis.
  • the former gradient is particularly advantageous for machining the molded body with a milling and/or grinding machine.
  • the gradient in the monolithic glass-ceramic molded body according to the invention is achieved by the continuously changing weight ratio of amorphous to crystalline portion and the continuously changing percentage weight fraction of zirconium dioxide crystals.
  • the gradient progression described above is not only limited to a gradual change in the crystalline and amorphous portions, but also applies to the proportion of zirconium dioxide crystals in the monolithic glass-ceramic molded body.
  • the zirconium dioxide in the monolithic glass-ceramic molded body according to the invention can be crystallized in such a way that a gradient is created which, in conjunction with the equally gradually changing ratio of the amorphous to the crystalline portion, produces a color and translucency profile that closely mimics the appearance of natural teeth.
  • the presence of the ZrO2 crystallites in the nanoscale also ensures that, despite the large difference in refractive index (ZrO2 compared to the rest of the molded body), an aesthetically pleasing material with sufficiently high translucency, even at the cervical level, is produced. Without being bound to any theory, it is assumed that the presence of nanoscale ZrO2 crystals contributes to the color and thus to the aesthetics of the molded body.
  • the translucency profile can be controlled by the varying amorphous portion in the molded body.
  • the monolithic glass-ceramic molded body according to the invention is intended in particular for the production of dental restorations and must be have sufficient strength for processing, but also be stable enough to withstand chewing forces. Therefore, an embodiment is preferred in which the shaped body according to the invention has a strength of 200 to 600 MPa, in particular 300 to 600 MPa, determined according to DIN EN ISO 6872:2019 in the 3-point bending test. Furthermore, a preferred embodiment of the shaped body according to the invention has a biaxial strength of 300 to 700 MPa, preferably 400 to 600 MPa. In a further preferred embodiment, the shaped body according to the invention has a Vickers hardness of 5000 to 8000 MPa, preferably 6000 to 7500 MPa after crystallization, determined according to ISO EN 6507:2018.
  • the blank according to the invention preferably has a fracture toughness of 1.0 to 3.0 MPa*ml/2, preferably 1.2 to 2.5 MPa*ml/2, each determined using the SEVNB method.
  • the gradient in the molded body is achieved by the continuously changing weight ratio of amorphous to crystalline portion and/or the proportion of zirconium dioxide crystals.
  • the gradient described above is not limited to a gradual change in the crystalline and amorphous portions, but also applies to the proportion of zirconium dioxide crystals in the glass-ceramic molded body.
  • the crystalline portion has different phases, with at least two of the phases differing from one another.
  • the optical properties of the monolithic glass-ceramic molded body according to the invention can be further adapted and optimized. These phases preferably differ with respect to at least one of the following properties:
  • the listed parameters influence the optical properties and can therefore be used as adjustments for further modifications.
  • the appearance of the molded article according to the invention can be individually adjusted.
  • the monolithic glass-ceramic molded body according to the invention consists of an amorphous and a crystalline portion.
  • the weight ratio of amorphous to crystalline portion ranges from 65:35 to 35:65, preferably from 60:40 to 40:60.
  • the present glass-ceramic molded body can be a monolithic molded body, thus achieving a seamless transition in the color and translucency gradient.
  • the molded body according to the invention is particularly distinguished by its optical properties. It has surprisingly been found that these properties develop particularly advantageously when the amorphous portion in the molded body lies within certain ranges. Therefore, an embodiment is preferred in which the amorphous portion in the molded body is 30 to 70 wt. %, preferably 40 to 60 wt. %, based in each case on the total weight of the molded body. In this way, a translucency profile corresponding to that of a natural tooth can be achieved.
  • the monolithic glass-ceramic molded body can comprise d and/or f elements. This can produce a color effect that differs from the color of the molded body without a crystalline component and can cause a continuous increase in color saturation.
  • Compounds of the d-elements can preferably be selected from the group consisting of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Nb, Mo, Ru, Rh, Pd, Ag, Cd, Lu, Ta, W, Re, Os, Ir, Pt and Au.
  • Compounds of the f-elements also known as lanthanides and actinides, can preferably be selected from the group consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb.
  • the d and f elements are preferably used as oxides.
  • oxides of the above-mentioned d- and/or f-elements can preferably be used in the monolithic glass-ceramic molded body according to the invention.
  • cerium oxide, terbium oxide, praseodymium oxide, erbium oxide, neodymium oxide, europium oxide, iron oxide, vanadium oxide and/or manganese oxide are preferred as compounds that support the desired color gradient.
  • the molded body according to the invention particularly preferably contains cerium oxide. This has made it possible to achieve particularly good color gradients that approximate natural tooth colors.
  • the d- and/or f-elements are particularly preferably present as oxides in an amount of 0.1 to 8 wt. %, particularly preferably 0.5 to 7 wt. %, and in particular 1 to 4 wt. Cerium oxide is especially preferred.
  • the compounds of the d- and/or f-elements are selected from the group consisting of oxides of the d- and/or f-elements, preferably selected from one or more oxides from the group consisting of cerium oxide, terbium oxide, praseodymium oxide, erbium oxide, neodymium oxide, europium oxide, iron oxide, vanadium oxide, and manganese oxide, as well as mixtures thereof.
  • oxides in particular, have demonstrated excellent color properties and, above all, an excellent color gradient in combination with the zirconium dioxide.
  • zirconium dioxide is preferably the host lattice, whose particles, usually zirconium, are replaced by a d- or f-element.
  • incorporation could be understood as meaning that the particles of the host lattice are substituted and/or inserted into existing gaps in the host lattice.
  • the resulting crystals are known to those skilled in the art as substitution and/or intercalation solid solutions.
  • ZrOz which is present as the main component, could impose its crystal structure on the compound of the d- and/or f-elements used, thereby changing the field of these cations in the lattice compared to that surrounding them in the glass matrix, resulting in a color effect.
  • incorporation of the crystals can be understood as doping of the ZrOz main crystal phase.
  • semiconductor technology a uniform distribution of the atoms in the main crystal phase is ensured by admixing the compounds of the d- and/or f-elements to be incorporated.
  • MzZn-zOz One way of describing the incorporated crystals in the main crystal phase is the above-mentioned expression MzZn-zOz, where M are metals selected from the compounds of the d- and/or f-elements present in the composition of the glass-ceramic molded body according to the invention.
  • z can be any rational number, preferably from 0.001 to 0.3, in particular from 0.002 to 0.1, especially from 0.003 to 0.05, which is determined by the reference domain.
  • the incorporation of the d and/or f elements can be ordered or random. This can be controlled using the melting temperature and/or crystallization temperature, which are known to the person skilled in the art.
  • the compounds mentioned can be incorporated into the monolithic glass-ceramic molded body in various forms Depending on the oxidation time and temperature, the compounds of the f- and d-elements are incorporated into the zirconium dioxide crystals. During the manufacturing process or crystallization, depending on the compound, the electron configuration of the incorporated f- or d-element can change, thus also altering the color saturation.
  • the monolithic glass-ceramic shaped body according to the invention can comprise the above-described mixed crystals MzZn-zÜ2, which are present as a crystal phase, preferably in an amount of 0.1 to 8 wt.%, in particular of 0.2 to 6 wt.% and particularly preferably of 0.3 to 4 wt.%, based on the total weight of the crystal phases in the shaped body, wherein M metals are selected from the group consisting of the compounds of the d and/or f elements present, wherein the metal is preferably an f element, very particularly preferably cerium.
  • mixed crystals comprise MzZn-zOz in a molar ratio of n(M)/n(Zr), where n(M) is the molar amount of the d- or f-element of the corresponding compound and n(Zr) is the molar amount of Zr from the ZrOz used, from 0.0001 to 0.6, preferably from 0.001 to 0.55, particularly preferably from 0.04 to 0.4, especially preferably from 0.1 to 0.3 and very particularly preferably from 0.1 to 0.2 based on the entire glass-ceramic shaped body, where M metals are selected from the group consisting of the compounds of the d- and/or f-elements present, where preferably the metal is an f-element, very particularly preferably cerium.
  • the gradual change in the percentage of zirconium dioxide by weight in the monolithic glass-ceramic molded body is responsible for the color effects and/or color saturation.
  • the color gradient and color saturation can be induced according to the gradual change in zirconium dioxide.
  • the gradient of the zirconium dioxide crystals, with the incorporated d- and/or f- elements, and the proportion of amorphous to crystalline portion preferably run from the tooth neck to the tooth enamel, so that the color saturation and/or the color gradient preferably increases from the tooth enamel to the tooth neck.
  • color saturation refers to how strongly a color differs from an achromatic stimulus, regardless of its brightness.
  • the colors white, gray, and black have a saturation of 0%, whereas bright colors have a saturation of 100%.
  • color saturation, chroma, colorfulness, color intensity, brilliance, color depth, and color strength are synonymous and thus interchangeable in the present invention.
  • the color can be characterized in particular by its L*a*b* value or by a color key commonly used in the dental industry.
  • Translucency is understood to mean the light transmittance of the glass-ceramic molded body according to the invention, which can change with the gradient.
  • Preferred values for L are from 60 to 90, particularly preferably from 70 to 80.
  • the value for a can be selected from the range from 0 to 6, particularly preferably from 0.1 to 5.
  • values from 5 to 40 are possible, preferably from 10 to 35. It is particularly preferred that for all parameters, i.e. L, a and b, higher values are selected at the tooth neck than at the tooth incisal edge for the respective parameter.
  • the color can be characterized by the difference in the L*a*b values.
  • the color difference between the tooth neck and the tooth incisal edge can be described by the difference in the L, a, and/or b values (hereinafter AL, Aa, and Ab).
  • AL can be from 0 to 10, preferably from 1 to 5, Aa from 0 to 5, preferably from 0.5 to 2.5, and Ab from 0 to 15, and preferably from 6 to 12.
  • the color difference can also be described using AE, which is familiar to those skilled in the art.
  • the AE is preferably from 0 to 15, particularly preferably from 0.5 to 10, for the color difference and/or color difference between the tooth neck and the tooth incisal edge.
  • the amorphous portion in the molded body changes only to a small extent, with a minimum amorphous portion being preferred.
  • the amorphous fraction in the shaped body along the gradient by at least 5 wt.%, preferably by at least 7 wt.%, but preferably by no more than 30 wt.%, in each case based on the total volume of the shaped body.
  • the change in the amorphous fraction in the shaped body along the gradient is in the range from 5 to 30 wt.%, preferably from 15 to 25 wt.%, in each case based on the total weight of the shaped body.
  • the glass-ceramic molded body according to the invention can also comprise at least one inorganic and/or organic coloring component.
  • coloring components are known to those skilled in the art.
  • Preferred coloring components are selected from the group consisting of compounds consisting of terbium, vanadium, manganese, and praseodymium, and in particular their oxides and/or mixtures of these compounds.
  • the compound of the structure M x O y is selected from cerium oxide, terbium oxide, praseodymium oxide, erbium oxide, neodymium oxide, europium oxide, iron oxide, vanadium oxide, and/or manganese oxide, and the same substances are additionally added as a coloring component. All combinations of M x O y and color pigments are possible.
  • a further preferred embodiment is a monolithic glass-ceramic molded body according to the invention, which has zirconium dioxide crystallites with a maximum size of 1000 nm, preferably 500 nm.
  • the size can be described by the Scherrer equation, which describes the extension of the crystal perpendicular to the lattice planes of the X-ray diffraction reflection.
  • crystals in this context mean a crystal cluster.
  • a zirconium dioxide crystal, or also called zirconium dioxide cluster is composed of several smaller zirconium dioxide (individual) crystals.
  • the size also called domain size, refers to the 2-dimensional view of a crystal or cluster (compare Fig. 1). Surprisingly, it was found that if the crystallites are too large, the shaped body becomes opaque. This is possibly due to a large difference in the refractive index.
  • the shaped body according to the invention thus has nanocrystalline ZrO2 (single) crystals in a cluster (compare Fig. 2), which preferably have a size of 200 nm or less, more preferably 100 nm or less, or especially preferably 50 nm or less.
  • the weight ratio of the zirconium dioxide crystals to the remaining crystalline and amorphous components changes gradually and continuously.
  • there can be an increase or decrease in the ratio of zirconium dioxide crystals present to the residual composition i.e. the sum of the amorphous and residual crystalline components.
  • the glass-ceramic molded body according to the invention can have a region that is virtually free of crystalline zirconium dioxide.
  • the expression "virtually free of crystalline zirconium dioxide” means that, in the preferred embodiment, less than 5 wt. %, more preferably less than 1 wt. %, and most preferably less than 0.1 wt. % of zirconium dioxide is present, based on the total weight of the zirconium-free region of the molded body. It is particularly preferred that the molded body has a region of 0 vol. % to 30 vol. %, from 1 vol. % to 35 vol. %, from 5 vol. % to 40 vol. % or from 10 to 50 vol.
  • the tooth cutting edge is the area in which the zirconium dioxide-free area of the glass-ceramic shaped body can preferably be present.
  • a particularly preferred embodiment is one in which the composition of the shaped body comprises from 56 to 59 wt.%, in particular from 56 to 58 wt.% SiO2, in each case based on the total weight.
  • composition of the shaped body comprises from 16 to 20 wt.% U2O, based on the total weight of the shaped body.
  • the molar ratio of Li2O:SiO2 in the molded body is from 1.5 to 2.5, which has proven to be particularly advantageous for the formation of a lithium silicate glass ceramic.
  • the composition of the shaped body comprises from 0.1 to 15 wt.%, preferably from 0.5 to 10 wt.% and particularly preferably from 1 to 8 wt.% zirconium dioxide in the shaped body, based on the total weight of the crystals of the shaped body.
  • the shaped body according to the invention can contain a proportion, preferably from 0 to 50% by volume, preferably from 5 to 40% by volume, in each case based on the total volume of the shaped body, which is almost free of zirconium dioxide crystals and in which the zirconium dioxide remains amorphous in the glass phase.
  • the glass ceramic shaped body according to the invention can comprise CeO2 in an amount of 0 to 6 wt.%, particularly preferably 0 to 4 wt.%, in particular 0.5 to 4 or 1 to 2.5 wt.% in the glass ceramic, in each case based on the total weight of the glass ceramic.
  • CeO2 causes a different color effect of the ZrC ⁇ crystals compared to the rest of the formed body.
  • the glass-ceramic shaped body according to the invention may comprise La2Ü3 in an amount of 0 to 1 wt.%, preferably 0.05 to 0.8 wt.%, in the glass-ceramic, in each case based on the total weight of the glass-ceramic.
  • the monolithic glass-ceramic shaped body according to the invention can be designed such that lithium disilicate is present as the main crystal phase, preferably in an amount of 51 to 75 wt.%, in particular of 52 to 65 wt.% and particularly preferably of 53 to 60 wt.%, based on the total weight of the crystal phases in the shaped body.
  • the monolithic glass-ceramic shaped body according to the invention is designed in a further preferred embodiment such that lithium metasilicate is present as a secondary crystal phase, preferably in an amount of 20 to 49 wt.%, in particular of 35 to 48 wt.% and particularly preferably of 30 to 47 wt.%, based on the total weight of the crystal phases in the shaped body.
  • lithium phosphate may be present as a secondary crystal phase, preferably in an amount of 5 to 15 wt.%, in particular 6 to 14 wt.% and particularly preferably 7 to 13 wt.%, based on the total weight of the crystal phases in the shaped body.
  • a further subject of the present invention is a method for producing a glass-ceramic molded body according to the invention, which comprises the following steps: a) providing a glass-ceramic blank that can form crystals by heat treatment, b) first homogeneous heat treatment preferably at a temperature of 500°C to 600°C for the preferential formation of nuclei, c) second homogeneous heat treatment at a temperature of 580°C to 720°C, wherein this temperature is preferably higher than the temperature in step b), in particular at a temperature of 610°C to 720°C for preferential pre-crystallization, and d) inhomogeneous heat treatment for the preferential formation of a preferably weight gradient of the zirconium crystals.
  • the gradient of the zirconium crystals is evident by a gradual increase in the weight of the zirconium crystals (concentration) along an axis running through the molded body.
  • the first homogeneous heat treatment is usually carried out with a holding time of more than 30 minutes, preferably from 30 minutes to 3 hours.
  • the second homogeneous heat treatment is typically carried out with a holding time of more than 30 minutes, preferably from 30 minutes to 3 hours.
  • the inhomogeneous heat treatment in step d) is typically carried out over a period of 15 to 220 minutes.
  • pre-crystallization is understood to mean a crystallization process that takes place at low temperatures and longer holding times and serves as a basis for the subsequent formation of smaller, in particular nanometer-sized ZrOz crystallites, as well as the main crystallization of the primary and secondary phases.
  • the inhomogeneous heat treatment of the blank in step d) preferably comprises at least one or more inhomogeneous heat treatments, which are carried out by setting an isothermal and/or non-isothermal heat gradient.
  • a first region of the blank is treated at a temperature TI and a second region of the blank is treated at a temperature T2, wherein the temperature difference between temperature TI and temperature 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 more and/or the temperature T2 is preferably higher than the temperature TI.
  • the temperature TI is preferably from 600 °C to 750 °C, particularly preferably in the range from 650 °C to 720 °C, while the temperature T2 preferably from 700 °C to 900 °C, particularly preferably from 740 °C to 860 °C, where T2 is higher than TI
  • the inhomogeneous heat treatment of the blank preferably takes place through contact with a heat source, whereby the contact can be direct or indirect.
  • the heat source can be a heat chamber or a heatable base.
  • the inhomogeneous heat treatment preferably imparts a heat gradient to the molded body, which preferably runs along an axis through the molded body.
  • the heat treatment is carried out by at least partially placing the blank, preferably in a form-fitting manner, into a heat chamber and heating the heat chamber. In this way, targeted heat treatment of individual areas of the blank can be achieved.
  • the heat chamber is preferably made of a thermally conductive material with a thermal conductivity of 50 to 500 W/(m*K), preferably 150 to 450 W/(m*K), determined by heat flow calorimetry.
  • the thermally conductive material is preferably selected from the group consisting of non-oxide ceramics, preferably selected from SiSn4, silicon carbide, and aluminum nitride, or metals.
  • the heating of the heating chamber can be adjusted depending on the intensity. In a preferred embodiment, the heating chamber is therefore heated indirectly by the new ambient atmosphere or, more preferably, directly through contact with a heat source.
  • the heat treatment of the blank can also be carried out using a heatable base onto which the blank is placed.
  • the contact can be indirect or direct, depending on the desired intensity. Therefore, an embodiment is preferred in which the heatable base is a heating plate onto which the blank is placed.
  • the heatable base can be a heat-conducting material that is heated, for example, via a heating plate, so that the heating of the blank occurs indirectly. Both types of heat treatment can also be combined.
  • the heat treatment is carried out in such a way that it takes place by the blank being at least partially, preferably in a form-fitting manner, introduced into a heat chamber and the heat chamber being heated, wherein, if appropriate, the temperature in the heat chamber is gradually increased in a further step, and/or the heat treatment is carried out by direct or indirect contact of the blank with a heat source, wherein the heat source is preferably a heating plate.
  • the present invention further relates to the use of the molded body according to the invention for producing dental restorations.
  • the molded body according to the invention is preferably used for producing dental restorations, preferably in the anterior tooth region, in particular veneers, crowns, inlays, and onlays.
  • the glass-ceramic molded body according to the invention is used in particular for restoring individual teeth, full dentures of the upper and/or lower jaw, dental bridges, and locator dentures.
  • Other dental purposes are familiar to the person skilled in the art, so the application of the glass-ceramic molded body is not limited to the list.
  • the present invention further provides a method for producing a dental restoration using the monolithic glass-ceramic molded body according to the invention, wherein, within the scope of the method according to the invention, a molded body according to the invention that has been subjected to at least a first inhomogeneous heat treatment is provided and subjected to a further, isothermal heat treatment.
  • the temperature of this isothermal heat treatment is preferably between 730 and 850 °C, particularly preferably in the range between 750 °C and 820 °C.
  • the holding time at this temperature is preferably between one and 60 minutes, particularly preferably between 5 and 30 minutes.
  • This process step can optionally also be directly linked to the first inhomogeneous heat treatment in the same furnace firing.
  • the method according to the invention further comprises machining the molded body to form the geometric shape of the dental restoration, preferably before the molded body is subjected to the further heat treatment.
  • Figure 1 shows the crystal structure and the size of the ZrOz crystal clusters of the glass-ceramic molded body according to the invention at the tooth neck, which was recorded via SEM.
  • Figure 2 shows a ZrO2 cluster according to the invention with the nanocrystalline ZrO2 crystals.
  • Figure 3 shows the change in the crystal structure of the glass-ceramic molded body according to the invention from the tooth neck (1) to the tooth incisal edge (12), which was recorded via SEM and XRD.
  • Figure 4 shows exemplary color measurements of different areas (platelet (1) tooth incisal to platelet (5) tooth neck) of the glass-ceramic body according to the invention, which were characterized via the color coordinate (measurement via reflection) and AE.
  • Figure 5 shows the crystalline composition of the crystal phase of the glass-ceramic molded body according to the invention from the tooth incisal (1) to the tooth neck (7), which was determined by Rietveld analysis, as well as a color measurement via transmission over a wavelength range of 360-750 nm.
  • Figure 6 shows the crystalline composition of the entire molded body (crystal phase and glass phase) of the glass-ceramic molded body according to the invention from the tooth incisal (1) to the tooth neck (7), which was determined by Rietveld analysis, as well as a color measurement via transmission over a wavelength range of 360-750 nm.
  • Figure 7 shows the temperature profiles of the process for producing a glass-ceramic molded body according to the invention.
  • Table 1 shows the measured reflection of four glass-ceramic molded bodies according to the invention. This is reflected as a color gradient from cutting edge to neck and is expressed as the characteristic L*a*b values.
  • Table 1 Color values for the different areas of the glass-ceramic molded body according to the invention
  • Table 2 shows the results of the Rietveld analysis of the molded bodies with MgO as the internal standard.
  • Four equal-sized sections A to D were prepared and measured at different locations on the molded body. The proportions are given in wt. %.
  • platelets were produced according to the glass-ceramic molding according to the invention. These platelets, shown in Fig. 4, were again examined for their color coordinates.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Dispersion Chemistry (AREA)
  • Glass Compositions (AREA)

Abstract

L'invention concerne un corps moulé en vitrocéramique monolithique pour restaurations dentaires, comprenant une proportion amorphe et une proportion cristalline, et est caractérisée en ce que le corps moulé contient (a) un rapport pondéral de la proportion amorphe sur la proportion cristalline variant de manière continue et progressive et (b) une proportion pondérale en pourcentage de cristaux de dioxyde de zirconium variant de manière continue et progressive dans le corps moulé ; le corps moulé comprenant du disilicate de lithium en tant que phase cristalline principale et le corps moulé comprenant les composants suivants : i) 56 à 64 % en poids, de préférence 56 à 59 % en poids de SiO2 ; ii) 15 à 21 % en poids, de préférence 16 à 20 % en poids de Li2O ; iii) 1 à 4 % en poids de K2O ; iv) 3 à 8 % en poids de P2O5 ; et v) 8 à 15 % en poids, de préférence 8 à 12 % en poids, plus précisément 9 à 11 % en poids de ZrO2.
PCT/EP2024/074841 2023-09-05 2024-09-05 Corps moulé en vitrocéramique à usage dentaire Pending WO2025051863A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP23195449 2023-09-05
EP23195449.6 2023-09-05

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WO2025051863A1 true WO2025051863A1 (fr) 2025-03-13

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2114348A2 (fr) 2007-03-06 2009-11-11 Hermsdorfer Institut für Technische Keramik e.V. Céramique pour incrustations vestibulaires pour des restaurations dentaires en dioxyde de zirconium stabilisé à l'yttrium et procédé de fixation d'incrustations vestibulaires sur des restaurations dentaires en dioxyde de zirconium stabilisé à l'yttrium
WO2013086187A1 (fr) 2011-12-08 2013-06-13 3M Innovative Properties Company Matière céramique à base de verre de type silicate de lithium, son procédé de production et d'utilisation
US20140000314A1 (en) 2010-04-16 2014-01-02 Ivoclar Vivadent Ag Lithium silicate glass ceramic and glass with ZrO2 content
EP2765119A1 (fr) 2013-02-12 2014-08-13 Ivoclar Vivadent AG Ébauche à des fins dentaires
US20160229742A1 (en) 2015-02-05 2016-08-11 Dentsply International Inc. Method for the production of a form body comprising or containing a lithium silicate glass ceramic as well as form bodies
WO2022179936A1 (fr) 2021-02-24 2022-09-01 Ivoclar Vivadent Ag Vitrocéramique comprenant une phase cristalline mixte de quartz
WO2024013368A1 (fr) 2022-07-14 2024-01-18 Vita Zahnfabrik H. Rauter Gmbh & Co. Kg Moulage de vitrocéramique à des fins dentaires

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2114348A2 (fr) 2007-03-06 2009-11-11 Hermsdorfer Institut für Technische Keramik e.V. Céramique pour incrustations vestibulaires pour des restaurations dentaires en dioxyde de zirconium stabilisé à l'yttrium et procédé de fixation d'incrustations vestibulaires sur des restaurations dentaires en dioxyde de zirconium stabilisé à l'yttrium
US20140000314A1 (en) 2010-04-16 2014-01-02 Ivoclar Vivadent Ag Lithium silicate glass ceramic and glass with ZrO2 content
WO2013086187A1 (fr) 2011-12-08 2013-06-13 3M Innovative Properties Company Matière céramique à base de verre de type silicate de lithium, son procédé de production et d'utilisation
EP2765119A1 (fr) 2013-02-12 2014-08-13 Ivoclar Vivadent AG Ébauche à des fins dentaires
US20160229742A1 (en) 2015-02-05 2016-08-11 Dentsply International Inc. Method for the production of a form body comprising or containing a lithium silicate glass ceramic as well as form bodies
WO2022179936A1 (fr) 2021-02-24 2022-09-01 Ivoclar Vivadent Ag Vitrocéramique comprenant une phase cristalline mixte de quartz
WO2024013368A1 (fr) 2022-07-14 2024-01-18 Vita Zahnfabrik H. Rauter Gmbh & Co. Kg Moulage de vitrocéramique à des fins dentaires

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