JP5662914B2 - Process for the preparation of dental restorations - Google Patents

Description

  The present invention relates to a process for the preparation of dental restorations in which lithium silicate glass ceramics and glasses having a high content of elements having a high atomic number are used.

Lithium silicate glass ceramics are characterized by very good mechanical properties, and for this reason these glass ceramics are long-term in the dental field and mainly for the preparation of dental crowns and small bridges. Has been used. Known lithium silicate glass ceramics usually as a main _{component, SiO 2, Li 2 O,} Al 2 O 3, alkali metal oxides (e.g., Na ₂ O or _K 2 O) and nucleating agent (e.g., _{P 2} O ₅ ). Furthermore, these glass ceramics can contain further components, for example, further alkali metal oxides and / or alkaline earth metal oxides and / or ZnO. Glass ceramics are also known which contain small amounts of further metal oxides, in particular coloring and fluorescent metal oxides.

Patent Document 1, 0 wt% to 2 wt% of ZrO _2, and 0.5 wt% to 7.5 wt%, and in particular coloring metal oxide from 0.5% to 3.5% by weight and fluorescence A lithium silicate glass ceramic is described which may further contain a functional metal oxide. US Pat. No. 6,057,031 is substantially free of ZnO and may contain 0 wt% to 4 wt% ZrO ₂ in addition to the above amounts of colorable and fluorescent metal oxides. Although a lithium silicate glass ceramic is described, in this document, a lower amount of ZrO ₂ between 0 wt% and 2 wt% is preferred to achieve high strength. These glass ceramics are processed into the desired dental restoration, in particular in the form of a lithium metasilicate glass ceramic, by CAD / CAM processes, where the subsequent heat treatment is performed on the metasilicate phase to a high strength disilicate phase. Cause a change.

U.S. Patent No. 6,099,059 relates to a lithium disilicate glass ceramic that may also contain transition metal oxides in addition to other components. In particular, it has been proposed to add small amounts of heavy elements (eg Sr, Y, Nb, Cs, Ba, Ta, Ce, Eu or Tb) for the purpose of increasing the refractive index of the glass matrix. Thus, for example, CeO ₂ and Tb ₄ O ₇ can be used in an amount of 0% to 1% by weight, and Nb ₂ O ₃ and Ta ₂ O ₅ are used in an amount of 0% to 2% by weight. And ZrO ₂ and Y ₂ O ₃ can be used in amounts of 0% to 3% by weight. In one embodiment, _Ta 2 _{O 5} is a specific example although containing this oxide up to 2.02 wt.%, Described as may be present in an amount of 0.5 wt% to 8 wt% ing.

Patent Documents 4 and 5, for the manufacture example of the crockery, discloses a glass ceramic, the glass ceramic, as a coloring agent, a specific transition metal oxides (e.g., CeO _2, Co ₃ O _4, Cr ₂ O ₃ , CuO, Fe ₂ O ₃ , MnO ₂ , NiO and V ₂ O ₅ ) may be contained in an amount of 0.01% to 7% by weight.

U.S. Patent Nos. 6,099,036 and 5,037,973 describe processes for forming dental restorations and glass ceramics that can be used in these processes. These glass-ceramics are particularly disilicate and lithium glass ceramic, 0 wt% to 5 wt% of coloring oxides _{(e.g., SnO 2, MnO, CeO,} Fe 2 O 3, Ni 2 O, V 2 O ₃ , Cr ₂ O ₃ or TiO ₂ ).

European Patent Application No. 1505041 European Patent Application No. 1688398 US Pat. No. 6,455,451 US Pat. No. 5,176,961 US Pat. No. 5,219,799 US Pat. No. 5,507,981 US Pat. No. 5,702,514

  Known glass ceramics based on lithium silicate often have optical properties that do not fully satisfy the aesthetic requirements, especially with respect to use as dental materials. Thus, known glass ceramics often have an undesirable refractive index. In particular, with glass ceramics, there is the problem that the refractive index of the crystalline phase and the refractive index of the glass phase are usually significantly different from each other, which in most cases leads to undesirable haze of the glass ceramic. Similar problems exist, for example, in the case of composites. This is because the refractive index of a known glass ceramic and the refractive index of glass are usually different from the refractive index of the polymer phase. Accordingly, there is a need for a lithium silicate-based glass ceramic whose refractive index can be easily changed, while other properties are not substantially compromised. Furthermore, such glass ceramics can be prepared and crystallized under conditions comparable to conventional glass ceramics, and these glass ceramics can be advantageously processed into dental restorations (eg inlays or crowns). It is desirable to be able to do so.

  The object of the present invention is to provide a process for preparing dental restorations in which glass ceramics and / or glasses can be used, which can avoid the above drawbacks and can be advantageously processed into the desired restoration. It is.

In order to solve the above problems, the present invention provides, for example:
(Item 1)
Process for the preparation of a dental restoration, wherein the lithium silicate glass ceramic or the lithium silicate glass is
(I) formed into the dental restoration by pressing or (ii) machining, wherein the glass ceramic and the glass contain at least 8.5 wt% transition metal oxide, A process selected from the group consisting of oxides of yttrium, oxides of transition metals having atomic numbers from 41 to 79, and mixtures of these oxides.
(Item 2)
Process according to the preceding items, wherein the dental restoration is selected from inlays, onlays, crowns, veneers, occlusal aspects and abutments.
(Item 3)
The process according to any one of the preceding items, wherein the pressing is carried out at a temperature of 700C to 1200C.
(Item 4)
Process according to any one of the preceding items, wherein the pressing is performed at a pressure of 2 bar to 10 bar.
(Item 5)
The process according to any one of the preceding items, wherein the machining is performed in a CAD / CAM process.
(Item 6)
The process according to any one of the preceding items, wherein the glass ceramic is a lithium metasilicate glass ceramic or a lithium disilicate glass ceramic.
(Item 7)
Process according to any one of the preceding items, wherein the glass comprises nuclei suitable for the formation of lithium metasilicate crystals and / or lithium disilicate crystals.
(Item 8)
The glass ceramic or the glass contains at least 8.5% by weight of a transition metal oxide, and the transition metal oxide includes an oxide of Y, an oxide of Nb, an oxide of La, an oxide of Ta, The process according to any one of the preceding items, selected from the group consisting of oxides of W and mixtures of these oxides.
(Item 9)
The glass ceramic or the glass has the following components:
Ingredient Weight%
SiO ₂ 54.0-80.0, especially 60.0-70.0
Li ₂ O 11.0 to 19.0, especially 13.0 to 17.0
Al ₂ O ₃ 0.2~8.0, especially 1.0 to 7.0
K ₂ O 0.5~13.5, especially 1.0 to 7.0
Alkaline earth metal oxides 0-6.0, especially 0.1-5.0
ZnO 0-6.0, especially 0.1-5.0
Transition metal oxide 8.5-30.0, especially 9.0-25.0
P ₂ O ₅ 0.5~12.0, especially 2.5 to 6.0
ZrO ₂ 0.1-4.0, especially 0.5-2.0
Colorant 0.1-8.0, in particular 0.2-2.0, and fluorescent agent,
A process according to any one of the preceding items, containing at least one and preferably all of the above.
(Item 10)
The process according to any one of the preceding items, wherein the glass ceramic and the glass are used in the form of a blank.
(Item 11)
The process according to any one of the preceding items, wherein after the machining, at least one heat treatment is performed to convert the formed glass or the formed glass ceramic into a lithium disilicate glass ceramic. process.
(Item 12)
A process according to any one of the preceding items, wherein the dental restoration is a lithium disilicate glass ceramic base.
(Item 13)
Use of a lithium silicate glass ceramic or a lithium silicate glass for preparing a dental restoration, wherein the glass ceramic or the glass is
(I) formed into the dental restoration by pressing or (ii) machining, and the glass ceramic and the glass contain at least 8.5% by weight of a transition metal oxide, the transition metal oxide Use selected from the group consisting of oxides of yttrium, oxides of transition metals having atomic numbers from 41 to 79, and mixtures of these oxides.

(Summary)
The present invention relates to a process for preparing a dental restoration in which a lithium silicate glass ceramic or lithium silicate glass containing at least 8.5% by weight of a transition metal oxide is used. Is selected from the group consisting of oxides of yttrium, oxides of transition metals having atomic numbers from 41 to 79, and mixtures of these oxides.

  The object is achieved by a process according to the appended claims 1-12. The subject of the invention is also the use according to claim 13.

  The present invention provides a process for preparing dental restorations in which glass ceramics and / or glasses can be used that can be advantageously processed into the desired restoration.

The process for preparing a dental restoration according to the present invention comprises a lithium silicate glass ceramic or a lithium silicate glass,
(Ii) characterized in that it is formed into a dental restoration by pressing or (ii) machining, wherein the glass-ceramic and the glass contain at least 8.5% by weight of a transition metal oxide; The transition metal oxide is selected from the group consisting of oxides of yttrium, oxides of transition metals having atomic numbers from 41 to 79, and mixtures of these oxides.

  The prepared dental restorations are preferably inlays, onlays, crowns, veneers, occlusal aspects and abutments.

  Preferably, dental restorations such as lithium silicate glass ceramic or a composite in which lithium silicate glass is coated on zirconium oxide ceramic are excluded. Particularly preferably, dental restorations comprising such composites are excluded.

  This dental restoration is preferably based on a lithium disilicate glass ceramic so as to have excellent optical and mechanical properties.

  The glass ceramic and the glass are preferably used in the form of a blank (eg block or cylinder) in the process according to the invention.

  Glass ceramic or glass pressing or machining processes the glass ceramic or glass into the desired dental restoration shape. Preferably, the press does not include pressing on another material (eg, zirconium oxide ceramic). Such a press serves to coat another material.

  This pressing is usually performed at high temperature and pressure. The pressing is preferably performed at a temperature of 700 ° C to 1200 ° C. Furthermore, the pressing is preferably carried out at a pressure of 2 bar to 10 bar. During pressing, the shape change is caused by the viscous flow of the material used.

  This machining is usually carried out by a material removal process and in particular by grinding and / or cutting. This machining is particularly preferably carried out in a CAD / CAM process. Furthermore, for the purpose of converting the formed glass or the formed glass ceramic to a lithium disilicate glass ceramic, it is preferable to carry out at least one heat treatment after machining.

  The lithium silicate glass ceramic used in the present invention is at least 8.5 selected from the group consisting of oxides of yttrium, oxides of transition metals having atomic numbers from 41 to 79, and mixtures of these oxides. It contains a transition metal oxide by weight%.

  In general, the glass ceramic used in the present invention or the transition metal oxide as a component of the glass used in the present invention has a substantial color change compared to the corresponding glass ceramic or the corresponding glass to which this component is not added. It is preferable not to cause it. Specifically, the transition metal oxide is colorless and / or non-fluorescent.

  The transition metal oxide is preferably selected from the group consisting of oxides of Y, Nb, La, Ta, W, and mixtures of these oxides.

  8.5 wt% to 30.0 wt%, preferably 9.0 wt% to 25.0 wt%, especially 9.5 wt% to 20.0 wt%, preferably 10.0 wt% to 18.0 Transition metal oxidation selected from one or more of the above groups by weight%, more preferably 10.5 wt% to 16.0 wt%, and most preferably 11.0 wt% to 15.0 wt% Glass ceramics containing the product are preferred.

  Surprisingly, according to the present invention, by using a high content of transition metal with a high atomic number, the refractive index of lithium silicate-based glass ceramics and glasses is substantially unaffected by other properties. Can be easily adjusted. In particular, unpredictably, a high content of transition metals with high atomic numbers usually does not interfere with the desired crystallization of lithium disilicate and does not result in the formation of undesirable secondary crystalline phases. As a result, the present invention results in a glass ceramic having excellent optical and mechanical properties.

54.0 wt% ～80.0 wt%, and glass-ceramic in particular containing 60.0 wt% 70.0 wt% of SiO _2, more preferably.

Furthermore, glass ceramics containing 11.0% to 19.0% by weight and in particular 12.0% to 15.0% by weight of Li ₂ O are preferred.

It has been shown to be particularly preferred when the glass-ceramic contains 0.5% to 12.0% by weight and in particular 2.5% to 6.0% by weight of nucleating agent. Preferred nucleating agents are selected from P ₂ O ₅ , TiO ₂ , metals (eg Pt, Pd, Au, Ag), or mixtures thereof. Particularly preferably, the glass ceramic contains P ₂ O ₅ as a nucleating agent. Surprisingly, P ₂ O ₅ , especially as a nucleating agent, results in the formation of the desired lithium disilicate crystals, while greatly preventing the formation of undesirable secondary crystal phases.

The glass ceramic used in the present invention preferably contains 0.5% to 13.0%, preferably 1.0% to 7.0%, and particularly preferably further alkali metal oxides. It is contained in an amount of 2.0% to 5.0% by weight. The term “further alkali metal oxide” refers to an alkali metal oxide other than Li ₂ O. This further alkali metal oxide is in particular K ₂ O, Cs ₂ O and / or Rb ₂ O, and particularly preferably K ₂ O. The use of K ₂ O is hypothesized to contribute to the strengthening of the glass network compared to Na ₂ O used in conventional glass ceramics. The glass ceramic preferably contains Na ₂ O of less than 2.0, in particular less than 1.0, preferably less than 0.5% by weight, and particularly preferably essentially free of Na ₂ O.

  It is further preferred that the glass ceramic contains up to 6.0% by weight and in particular 0.1% to 5.0% by weight of alkaline earth metal oxide, wherein the alkaline earth metal oxide is In particular, CaO, BaO, MgO, SrO or a mixture thereof.

  More preferably, the glass-ceramic contains up to 6.0% by weight and in particular 0.1% to 5.0% by weight of ZnO.

  The glass ceramic used in the present invention may also contain further components, in particular these trivalent element oxides, further tetravalent element oxides, further pentavalent element oxides, melting Selected from accelerators, colorants and fluorescent agents.

Glass containing 0.2% to 8.0% by weight, in particular 1.0% to 7.0% by weight and preferably 2.5% to 3.5% by weight of oxides of trivalent elements Ceramics are preferred, and the oxide is selected in particular from Al ₂ O ₃ , Bi ₂ O ₃ and mixtures thereof, and is preferably Al ₂ O ₃ .

The term “an oxide of a further tetravalent element” refers to an oxide of a tetravalent element other than SiO ₂ . Examples of further tetravalent element oxides are ZrO ₂ , SnO ₂ and GeO ₂ , in particular ZrO ₂ .

The term “further pentavalent oxide” refers to oxides of pentavalent elements other than P ₂ O ₅ . An example of a further pentavalent oxide is Bi ₂ O ₅ .

  Preference is given to glass-ceramics containing at least one further tetravalent oxide or further pentavalent oxide.

  An example of a melting accelerator is fluoride.

  Examples of colorants and fluorescent agents are chromogenic or fluorescent oxides of element d and element f (eg Sc, Ti, Mn, Fe, Ag, Ce, Pr, Tb, Er and Yb, in particular Ti, Mn, Fe, Ag, Ce, Pr, Tb, and Er oxides).

The following ingredients:
Ingredient weight%
SiO ₂ 54.0-80.0, especially 60.0-70.0
Li ₂ O 11.0 to 19.0, especially 12.0 to 15.0
K ₂ O 0.5~13.5, especially 1.0 to 7.0
Al ₂ O ₃ 0.2~8.0, especially 1.0 to 7.0
Alkaline earth metal oxides 0-6.0, especially 0.1-5.0
ZnO 0-6.0, especially 0.1-5.0
Transition metal oxide 8.5-30.0, especially 9.0-25.0
P ₂ O ₅ 0.5~12.0, especially 2.5 to 6.0
ZrO ₂ 0.1-4.0, especially 0.5-2.0
Particular preference is given to glass-ceramics containing at least one and preferably all of the colorants 0.1 to 8.0, in particular 0.2 to 2.0 and the fluorescent agent.

  The term “primary crystal phase” used below refers to a crystal phase having the highest volume ratio compared to other crystal phases.

  The glass ceramic used in the present invention preferably has lithium metasilicate as the main crystal phase. In particular, the glass ceramic contains more than 5% by volume, preferably more than 10% by volume and particularly preferably more than 15% by volume of lithium metasilicate crystals relative to the total glass ceramic.

  In a further preferred embodiment, the glass ceramic has lithium disilicate as the main crystalline phase. In particular, the glass ceramic contains more than 5% by volume, preferably more than 10% by volume and particularly preferably more than 15% by volume of lithium disilicate crystals relative to the total glass ceramic.

  The lithium disilicate glass ceramic used in the present invention is characterized by particularly good mechanical properties and can be produced by heat treatment of the lithium metasilicate glass ceramic used in the present invention. This can also be affected by high temperature pressing on the desired dental restoration according to the present invention.

  Despite its high content of transition metals with high atomic numbers, the lithium disilicate glass ceramics used in the present invention usually have good translucency and have an amorphous-amorphous phase. It is also surprising that no separation occurs.

  In addition to good mechanical properties, the lithium disilicate glass ceramic used in the present invention also has high chemical resistance.

  Also in the process according to the invention, lithium silicate glass containing the components of the glass ceramic used in the invention can be used. With regard to this preferred embodiment of the glass, reference is made to the preferred embodiment of the glass ceramic used in the present invention. Surprisingly, despite the high content of transition metals with high atomic numbers, homogeneous transparent glasses can be obtained, such as amorphous-amorphous phase separation or spontaneous crystallization. It was shown not to exhibit the undesirable phenomenon of These glasses are suitable for the preparation by heat treatment of the glass ceramic used in the present invention.

  Particularly preferred are lithium silicate glasses having nuclei suitable for the formation of lithium metasilicate crystals and / or lithium disilicate crystals.

  The glass used in the present invention with nuclei can be produced by heat treatment of a correspondingly constructed starting glass. By further heat treatment, a lithium metasilicate glass ceramic according to the invention can then be formed, which can then be converted into a lithium disilicate glass ceramic according to the invention by further heat treatment. Starting glass, glass with nuclei, and lithium metasilicate glass ceramic can consequently be considered precursors for the production of high strength lithium disilicate glass ceramic. The heat treatment required for this conversion can also be affected during pressing at high temperatures. This not only affects the formation of the glass or glass ceramic used for the desired dental restoration, but also converts these glass or glass ceramic (eg, glass with nuclei to glass ceramic). Or the conversion of lithium metasilicate glass ceramic to lithium disilicate glass ceramic.

  The glass and glass ceramic used in the present invention are usually in the form of blanks. This is because these blanks can easily be further processed in this form.

  The process for the preparation of the glass ceramic used in the present invention and the glass with core used in the present invention is such that the glass ceramic or the starting glass having the components of the glass is in the range of 450 ° C to 950 ° C. It is characterized by being subjected to at least one heat treatment.

The starting glass thus contains at least 8.5% by weight of at least one transition metal oxide as defined above. In addition, the starting glass also preferably contains suitable amounts of SiO ₂ and Li ₂ O in order to allow the formation of a lithium silicate glass ceramic. In addition, the starting glass may also contain additional components such as those given above for the lithium silicate glass ceramic used in the present invention. Embodiments given as preferred for glass ceramics are also preferred.

  In order to prepare the starting glass, the procedure is notably a mixture of suitable starting materials (eg carbonates, oxides, phosphates and fluorides), especially at temperatures of 1300 ° C. to 1600 ° C., preferably 1450 ° C. to 1500 ° C. And a process that is melted for 2 to 10 hours. In order to achieve a particularly high homogeneity, the resulting glass melt is poured into water for the purpose of forming glass granules, and the resulting granules are then melted again.

  This melt can then be poured into a mold to produce a starting glass blank (so-called solid glass blank or monolithic blank). The cooling is preferably performed from a temperature of 500 ° C. to room temperature at a cooling rate of 3 K / min to 5 K / min. This is particularly advantageous for producing stress-free glass products.

  It is also possible to put this melt back into water for the purpose of preparing granules. The granules can then be pressed after grinding and optionally adding further ingredients (eg colorants and fluorescent agents) to form blanks (so-called powder green compacts).

  Finally, the starting glass can also be processed to form a powder after granulation.

  The starting glass is then subjected to at least one heat treatment in the range of 450 ° C. to 950 ° C., for example in the form of a solid glass blank, powder green compact or powder. The first heat treatment is performed at a temperature in the range of 500 ° C. to 600 ° C. in order to prepare the glass used in the present invention having suitable nuclei for forming lithium metasilicate crystals and / or lithium disilicate crystals. It is preferable to carry out first. The glass can then preferably be subjected to at least one further temperature treatment at higher temperatures (especially greater than 570 ° C.) to cause crystallization of lithium metasilicate or lithium disilicate.

  This at least one heat treatment can also be carried out during pressing at high temperatures in the process according to the invention. It is also possible by this heat treatment to convert the glass or glass ceramic used after it has been machined, and in particular to convert this glass or glass ceramic into a high strength lithium disilicate glass ceramic.

  Dental restorations (eg, inlays, onlays, crowns, veneers, occlusal aspects or abutments) can be prepared from the glass ceramic used in the present invention and the glass used in the present invention. The invention therefore also relates to the use of these glass ceramics or glasses for the preparation of dental restorations. In this connection, the glass ceramic or glass is preferably formed into the desired dental restoration by pressing or machining. This pressing is carried out in particular at high pressure (eg 2 bar to 10 bar) and high temperature (eg 700 ° C. to 1200 ° C.). In particular, the process and press furnace disclosed in EP 231 773 can be used. A suitable furnace is, for example, the Program EP 5000 from Iechclar Vivadent AG from Liechtenstein. For pressing, in particular the starting glass according to the invention, and preferably the glass with the core according to the invention, the lithium metasilicate glass ceramic according to the invention, and the lithium disilicate glass ceramic according to the invention are, for example, in the form of blanks. And can be used.

  Machining is usually carried out in a CAD / CAM process, which in particular uses the lithium metasilicate and lithium disilicate glass ceramics of the invention, preferably in the form of suitable blanks. This machining is performed in particular by a material removal process (eg grinding and cutting).

  After the preparation of a dental restoration shaped into the desired shape by pressing or machining, the dental restoration is further heat treated in particular to obtain a precursor (eg starting glass, glass with nuclei or lithium metasilicate). Can be converted to lithium disilicate glass ceramic.

Finally, the glasses and glass ceramics according to the invention can also be mixed with other glasses and glass ceramics to give dental materials with desirable tuned properties. Thus, a glass or glass ceramic containing a glass according to the invention or a glass ceramic according to the invention represents a further embodiment of the invention. Thus, the glass according to the invention or the glass ceramic according to the invention can in particular be used as the main component of an inorganic / inorganic composite or can be used in combination with a number of other glasses and / or glass ceramics. These composites or combinations are preferably used as dental materials. It is particularly preferred to use these composites and combinations in the form of a sintered blank. Examples of other glasses and glass-ceramics for producing inorganic-inorganic composites and mixtures are DE 43 14 817, DE 44 23 793, DE 44 28 839, DE 196 47 739, DE 197 25 552 and DE 100 31. 431. These glasses and glass ceramics belong to the group of silicates, borates, phosphates or aluminosilicates. Preferred glass and glass ceramic are SiO ₂ —Al ₂ O ₃ —K ₂ O type (having cubic or tetragonal leucite crystals), SiO ₂ —B ₂ O ₃ —Na ₂ O type, alkali Silicate type, alkali-zinc-silicate type, silico-phosphate type and / or SiO ₂ —ZrO ₂ type. By mixing such glasses and / or glass ceramics with the glasses and / or glass ceramics according to the invention, for example, the coefficient of thermal expansion is in the desired manner 6-20 × 10 ⁻⁶ × 1 / K. It is possible to adjust in a wide range.

  The invention is described in more detail below with reference to examples.

Examples 1 to 10-Composition and crystal phase
A total of 10 glasses and glass-ceramics having the compositions given in Table I (each in wt%) were prepared by melting the corresponding starting glass followed by heat treatment for controlled nucleation and crystallization. .

  These starting glasses were first converted to glass frit on a scale of 100 g to 200 g from conventional materials at 1400 ° C. to 1500 ° C. and poured into water. These glass frits were then melted for a second time at 1450 ° C. to 1550 ° C. for 1 to 3 hours for homogenization. The resulting glass melt was poured into a preheated mold to produce a glass monolith. These glass monoliths were converted into glasses and glass ceramics according to the invention by heat treatment.

  The crystalline phase obtained after completion of all heat treatments was determined by high temperature X-ray diffraction (HT-XRD) at the temperatures listed in Table I in each case. Surprisingly, glass ceramics containing lithium disilicate as the main crystalline phase have always been obtained. Despite the high content of transition metals with high atomic numbers, no secondary crystalline phase was seen in these transition metals.

  Finally, the refractive index of each glass phase was determined using an Abbe refractometer (20 ° C., 589 nm). It has been shown that the glass ceramic according to the invention has a significantly higher refractive index than the comparative glass ceramic.

（実施例１１ - ホットプレスまたは機械加工（ＣＡＤ／ＣＡＭ）による歯科用修復物の直接調製）
（Ａ）核を有するガラスのブランク
最初に、実施例７および実施例８による組成を有するガラスを、酸化物および炭酸塩の形態の対応する原料をＴｕｒｂｏｌａミキサー中で３０分間混合し、次いでこの混合物を白金坩堝内で１４５０℃で１２０分間融解することによって調製した。微細に分割されたガラス顆粒を得る目的で、この融解物を水に注いだ。特に高い均質性を有するガラス融解物を得る目的で、これらのガラス顆粒を再度、１５３０℃で１５０分間融解した。温度を３０分間にわたって１５００℃まで下げ、引き続いて、ａ）矩形ガラスブランク（１２．５ｍｍ×１４ｍｍ×４０ｍｍ）およびｂ）１２．５ｍｍの直径を有する円柱形ガラスブランクを、予熱した分離可能な鋼型または黒鉛型に注いだ。次いで、得られた矩形ガラスブロックまたはガラス円柱を、その組成に依存して５００℃〜５６０℃の範囲で熱処理して、メタケイ酸リチウム結晶および／または二ケイ酸リチウム結晶のための核を生成し、そしてガラスの応力を軽減した。

Example 11-Direct preparation of dental restoration by hot pressing or machining (CAD / CAM)
(A) Glass blank with nuclei First, a glass having the composition according to Example 7 and Example 8 is mixed for 30 minutes in a Turbola mixer with the corresponding raw materials in the form of oxides and carbonates, and then this mixture Was prepared by melting in a platinum crucible at 1450 ° C. for 120 minutes. This melt was poured into water in order to obtain finely divided glass granules. In order to obtain a glass melt with a particularly high homogeneity, these glass granules were again melted at 1530 ° C. for 150 minutes. The temperature was lowered to 1500 ° C. over 30 minutes, followed by a) a separable steel mold that was preheated from a cylindrical glass blank (12.5 mm × 14 mm × 40 mm) and b) a cylindrical glass blank having a diameter of 12.5 mm. Or poured into a graphite mold. The resulting rectangular glass block or glass cylinder is then heat treated in the range of 500 ° C. to 560 ° C. depending on its composition to produce nuclei for lithium metasilicate crystals and / or lithium disilicate crystals. , And reduced the stress on the glass.

  The resulting blank with nuclei was processed into a restoration according to the following alternative.

(B) Hot pressing of glass with nuclei, lithium metasilicate or lithium disilicate glass ceramic i) A glass cylinder (A) with nuclei is subjected to a temperature of 900 ° C. to 950 ° C. in a press furnace EP600 (Ivoclar Vivadent AG). Processed by hot pressing to obtain dental restorations (eg, inlays, onlays, veneers, partial crowns, crowns and occlusal aspects).

  ii) The glass cylinder (A) having a nucleus was subjected to a first crystallization at 650 ° C. to 750 ° C. for 20 minutes. The heating rate was 15 ° C. per minute. After this first crystallization, lithium metasilicate was detected as the main crystal phase. Dental restorations (e.g., inlays, onlays, veneers, partial crowns, by hot pressing lithium metasilicate glass cylinders using a press furnace EP600 (Ivoclar Vivadent AG) at a pressing temperature of 900C to 950C. It was possible to produce a crown and occlusal aspect). This hot press converted lithium metasilicate to lithium disilicate.

  iii) The glass cylinder (A) with nuclei was subjected to a further heat treatment at 840 ° C. to 880 ° C. for 5 to 30 minutes following the first crystallization according to ii). Analysis of the crystal phase after this treatment showed a glass ceramic according to the invention having lithium disilicate as the main crystal phase. The crystallized cylinder obtained after this second crystallization was subsequently hot pressed at a press temperature of 900 ° C. to 950 ° C. using a press furnace EP600 (Ivoclar Vivadent AG), for example, a dental restoration (for example, Inlay, onlay, vestibule, partial crown, crown and occlusal phase).

(C) Machining of lithium metasilicate (CAD / CAM process)
The rectangular glass block (A) having nuclei was subjected to the first crystallization according to (B) (ii) to crystallize lithium metasilicate. The resulting lithium metasilicate glass ceramic block is then machined by a CAD / CAM process (eg, Sirona, Cerec 2® or Cerec 3®) to provide a dental restoration (eg, an inlay , Onlay, vestibule, partial crown, crown and occlusal phase). Subsequently, these restorations were subjected to a second crystallization at 840 ° C. to 880 ° C. for 5 minutes to 1 hour. Analysis of the crystal phase after this treatment showed a glass ceramic according to the invention having lithium disilicate as the main crystal phase.

Claims (23)

Process for the preparation of a dental restoration, wherein the lithium silicate glass ceramic or the lithium silicate glass is
(I) formed into the dental restoration by pressing or (ii) machining, wherein the glass ceramic and the glass contain at least 8.5 wt% transition metal oxide, A process selected from the group consisting of yttrium oxide, Nb oxide, La oxide, Ta oxide, W oxide, and mixtures of these oxides.   The process of claim 1, wherein the dental restoration is selected from inlays, onlays, crowns, veneers, occlusal aspects and abutments.   The process according to claim 1 or 2, wherein the pressing is performed at a temperature of 700C to 1200C.   The process according to any one of claims 1 to 3, wherein the pressing is performed at a pressure of 2 bar to 10 bar.   The process according to claim 1, wherein the machining is performed in a CAD / CAM process.   The process according to any one of claims 1 to 5, wherein the glass ceramic is a lithium metasilicate glass ceramic or a lithium disilicate glass ceramic. The process according to claim 1, wherein the glass contains nuclei for the formation of lithium metasilicate crystals and / or lithium disilicate crystals. The glass ceramic or the glass has the following components:
Ingredient weight%
SiO ₂ 54.0~80. 0
L i ₂ O 11.0~19. 0
A l ₂ O ₃ 0.2~8. 0
K ₂ O 0.5~13. 5
A alkaline earth metal oxide 0-6. 0
Z nO 0~6. 0
Transition metal oxide from 8.5 to 30. 0
P ₂ O ₅ 0.5~12. 0
Z rO ₂ 0.1~4. 0
Wearing colorant 0.1 to 8. 0
And fluorescent agents
At least one containing A process according to any one of claims 1 to 7 out of.   The process of claim 8, wherein the glass ceramic or the glass contains all of the components.   The glass ceramic or the glass is 60.0-70.0 wt% SiO. ₂ The process according to claim 8 or 9, which contains   The glass ceramic or the glass is 13.0 to 17.0 wt% Li ₂ The process according to any one of claims 8 to 10, comprising O.   The glass ceramic or the glass is 1.0 to 7.0% by weight of Al. ₂ O ₃ The process according to any one of claims 8 to 11, comprising:   The glass ceramic or the glass is 1.0 to 7.0% by weight of K. ₂ The process according to any one of claims 8 to 12, comprising O.   The process according to any one of claims 8 to 13, wherein the glass ceramic or the glass contains 0.1 to 5.0% by weight of an alkaline earth metal oxide.   The process according to claim 8, wherein the glass ceramic or the glass contains 0.1 to 5.0% by weight of ZnO.   The process according to any one of claims 8 to 15, wherein the glass ceramic or the glass contains 9.0 to 25.0% by weight of a transition metal oxide.   The glass ceramic or the glass is 2.5 to 6.0% by weight of P. ₂ O ₅ The process according to any one of claims 8 to 16, comprising:   The glass ceramic or the glass is 0.5 to 2.0% by weight of ZrO. ₂ The process according to any one of claims 8 to 17, comprising:   The process according to any one of claims 8 to 18, wherein the glass ceramic or the glass contains 0.2 to 2.0 wt% of a colorant and a fluorescent agent. The glass ceramic and the glass is used in the form of a blank, according to any one of claims 1 to 19 process. After the machining, at least one thermal treatment is performed, to convert the formed glass or the formed glass ceramic the lithium disilicate glass ceramic, according to any one of claims 1 to 20 Process. The dental restoration is a lithium disilicate glass ceramic base, the process according to any one of claims 1 to 21. Use of a lithium silicate glass ceramic or a lithium silicate glass for preparing a dental restoration, wherein the glass ceramic or the glass is
(I) formed into the dental restoration by pressing or (ii) machining, and the glass ceramic and the glass contain at least 8.5% by weight of a transition metal oxide, the transition metal oxide Is selected from the group consisting of oxides of yttrium, oxides of Nb, oxides of La, oxides of Ta, oxides of W, and mixtures of these oxides.