WO2018023181A1 - Vitrocéramiques usinables à haute ténacité à la rupture, et utilisation de celles-ci - Google Patents

Vitrocéramiques usinables à haute ténacité à la rupture, et utilisation de celles-ci Download PDF

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WO2018023181A1
WO2018023181A1 PCT/BR2017/000087 BR2017000087W WO2018023181A1 WO 2018023181 A1 WO2018023181 A1 WO 2018023181A1 BR 2017000087 W BR2017000087 W BR 2017000087W WO 2018023181 A1 WO2018023181 A1 WO 2018023181A1
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glass
ceramics
machinable
meta
sio
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PCT/BR2017/000087
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Portuguese (pt)
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Edgar DUTRA ZANOTO
Vibiane OLIVEIRA SOARES
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Fundação Universidade Federal De São Carlos
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C5/00—Filling or capping teeth
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C13/00—Dental prostheses; Making same
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/20—Silicates
    • C01B33/32—Alkali metal silicates
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/16—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on silicates other than clay

Definitions

  • the present invention belongs to the field of machinable glass ceramics, more particularly to glass ceramics containing lithium metasilicate as the main phase (> 50% vol.), The formation of this crystalline phase enabling the machining of glass ceramics and the production of high quality workpieces. dimensional complexity for dental applications.
  • Vitroceramics or glass ceramics are inorganic materials obtained by the controlled crystallization of glasses. These materials may contain a variable amount (from 99 to 1%) of residual glassy phase and one or more dispersed crystalline phases.
  • the vitroceramics of the Li 2 O-SiO 2 (LS) system have high commercial value and the most cost-effective products are dental prostheses containing lithium disilicate (Li 2 Si 2 O 5 ) as the main crystalline phase, see the order publication.
  • Glass - ceramics containing Li 2 Si 2 Ostambém have other applications such as ballistic protection plates, hard disk substrate and others.
  • the main characteristics of these materials are: high mechanical strength, translucency, high fracture toughness and high chemical durability. Thus, these materials can be applied in the manufacture of dental prostheses and restorations.
  • the most modern dental ceramics are obtained by injection molding or CAD / CAM (Computer Aided Design / Computer Aided Manufacturing).
  • CAD / CAM Computer Aided Design / Computer Aided Manufacturing
  • the machinable glass ceramic of the invention can also be machined by the CAD / CAM method, the main advantage of this technique is that it does not require the use of elevated temperatures. [0005] These materials can also be processed by the lost wax method.
  • Apel et al. evaluated the influence of the addition of zirconia (0-4 wt%) on the crystallization of glass of Li 2 O-SiO 2 -AI 2 Or-K 2 OP 2 O 5 system to obtain lithium disilicate vitroceramics, see Apel, E .; Van'tHoen, C; Rheinberger, V .; Hand, W. influence of ZrO 2 on crystallization and properties of lithium disilicate glass-ceramics derived from a multi- oomponent system. Journal of the European Ceramic Society, v. 27, no. 2-3, p. 1571-1577, 2007.
  • the shaped parts were subsequently sintered for 11 hours at 1500 ° C, ensuring excellent flexural strength of these materials, 900 MPa at 1300MPa.
  • Other companies such as Everest, KaVo, DC-Zirkon, President DCS have chosen to market ZrO 2 blocks only, to minimize part shrinkage during heat treatment, see Ariko K. Evaluation of marginal fitness of tetragonal zirconia polycrystal all-ceramic restorations . Kokubyo Gakkai Zasshi, v. 70, no. 2, p. 114-123, 2003. These parts also have satisfactory flexural strength.
  • IPS Empress II product which is a glass ceramic containing lithium disilicate and formed by injection molding by the lost wax method.
  • the pieces can be coated with a ceramic glaze specially developed for these materials.
  • a 5-year study revealed a 70% success rate for dental crowns (2-tooth bridges) made from this material, see Marquardt, P .; Strub, JR. Su n / i will rates of IPS Empress 2 ali- ceramic crowns and fixed partial dentures: findings from a 5-year prospective clinical study. Quintessence Int.2006; 37 (4): 253-259.
  • Lithium disilicate containing vitroceramics cannot be machined.
  • a machinable intermediate product was developed.
  • This product contains lithium metasilicate ( ⁇ 40% vol.), Its trade name is IPS e.max CAD and is blue in color.
  • the product has low chemical durability, after being machined the part is heat treated at 850 ° C and the lithium metasilicate phase and part of the residual glass turn into lithium disilicate ( ⁇ 70% vol.), Forming a vitroceramic chemically durable and aesthetically similar to the natural tooth. Before heat treatment an enamel can be applied to the part to adjust the color to suit the patient.
  • the end product features excellent flexural strength from 360 MPa to 617 MPa, fracture toughness (K Ic ) of 2.3 MPa.m 1 ' 2 and excellent chemical durability (less than 100 ⁇ g / cm 2 in weight loss). according to ISO 6872), see Holland, W .; Beall, GH Glass-Ceramic Technology, Second Edition. New Jersey: Wiley, 2012, p. 414.
  • Li 2 O.SiO 2 glass ceramics The most important property of the Li 2 O.SiO 2 glass ceramics is the high fracture toughness. This property results mainly from the crystallization of the phases: lithium metasilicate (Li 2 SiO 3 ) or lithium disilicate (U 2 Si 2 O 5), see Serbena, F. C; Mathias, I .; Foerster, CE; Zanotto, ED Toughening Crystallization of a modelglass-ceramic. Acta Materialia no. 86, p. 216-228, 2015 and Holland.W .; Rheinberger, V .; The skin.; VaiYtHoen, C. Principles and phenomena of bioengineering with glass ceramics for dental restoration. Journal of the European Ceramic Society, no. 27, v. 2-3, p. 1521-1526, 2007. SUMMARY OF (NVENTION
  • the present invention deals with machinable glass ceramics containing lithium metasilicate as the main phase (> 50% vof.) To allow the machining of glass ceramics and production of high dimensional complexity parts.
  • the lithium metasilicate phase in the glass ceramics of the invention is in a proportion of at least 50% vol. and up to 80% vol. of lithium metasilicate.
  • an object of the invention is directed to machinable glass ceramic with lithium metasilicate crystalline phase between 50% vol. and up to 80% vol.
  • a further object of the invention is directed to machinable glass ceramic with fracture toughness of at least 3.5 ⁇ 0.5 MPa.m 1/2 pe (the double twist method.
  • a further object of the invention is directed to machinable glass ceramics of excellent machinability, translucency (10% to 20% visible spectrum region transmission), good chemical durability (acetic acid solubility ⁇ 25C ⁇ g / cm 2 ) and free from cytotoxicity.
  • An additional object of the invention is directed to machinable glass ceramics useful for making complex sized ceramic pieces via machining such as parts employed in dental applications.
  • a further object of the invention is directed to the use of machinable glass ceramics in dental parts prepared by CAD / CAM machining.
  • the attached Figure 1 shows the DSC curves of meta compositions 01.02, 03, 04.05, 07 and 10.
  • the attached Figure 2 shows the DSC curve of the meta 07 composition.
  • the attached Figure 3 shows the DSC curve of the meta 08 and 09 compositions.
  • the attached Figure 4 shows the X-ray diffractograms of the meta 01 compositions; 02; 04; 05 obtained from the treatments listed in Table 2.
  • the attached Figure 5 shows the X-ray chart of the meta03 composition treated at 650 ° C for 30min and at 458 ° C for 5min followed by treatment at 650 ° C for 3min.
  • the attached Figure 6 shows the polished surface of the meta 03 glass ceramic treated at 460 ° C / 5min; 800 ° C / 3min and cooled to 10 ° C / min after chemical attack in HF solution a) 5% HF attack for 5s, BSE detector; b) 5% HF attack for 5s, SE detector; c) 2% HF attack for 10s and d) rough fracture surfaces.
  • the attached Figure 7 shows the meta-vitroceramic treated at 450 ° C / 3h and 800 ° C using a heating and cooling rate of 10 ° C / min. Fractured surface chemically etched in HF 2% vol. for 10s.
  • the attached Figure 8 shows the hardness and elastic modulus of the glass ceramic meta 03 as a function of the contact depth of the indenter.
  • Attached Figure 9 is a photo showing the Glass-ceramic meta 03 attached to a metal pin - step prior to machining.
  • Attached Figure 10 is a photo showing a CAO / CAM machined molar tooth from the meta 03 glass ceramic and fixed to a dental mannequin.
  • the attached Figure 11 is a graph showing the wavelength transmittance for the meta03 glass ceramic.
  • the attached Figure 12 is a graph showing wavelength transmittance for e-max Press commercial material.
  • the attached Figure 13 is a graph showing wavelength transmittance for glass ceramic compositions meta 04 with 0.67 mm thickness and meta OS with 0.60 mm thickness heat treated at 475 ° C / 5min and 950 ° C / 15min.
  • the attached Figure 14 is a graph showing the thermal expansion of the meta 03 glass ceramic as a function of temperature.
  • the attached Figure 15 is a barcode showing the cellular viability of the samples: glass ceramic meta 03, glass ceramic and. Press
  • the term "high fracture toughness” means that the fracture toughness values for the materials of the invention are equal to or greater than 3.5 ⁇ 0.5 MPa.m 1/2 when determined by the method. of doubling twist.
  • the developed glass ceramic exhibits very high fracture toughness, excellent machinability, translucency, good chemical durability and free from cytotoxicity.
  • Stoichiometric glasses of lithium metasilicate are very difficult to obtain due to the devitrification, which consists in the unwanted formation of crystals during the cooling of the glass, previously poured into a mold.
  • the compositions of the invention were made from the addition of other minor oxides that could increase the stability of the glass.
  • the silica content was limited to the range of 50-65% in mot.
  • compositions were made to have a crystallized fraction of greater than 50% vol. observing the stoichiometry of the crystal phase Li 2 SiO 3 (lithium metasilicate).
  • Other components were added to the composition such as fluxes (K 2 O, BaO, CaO, Na 2 O, MgO), formers (Al 2 O 3, P 2 O 5 , B 2 O â ) and others (TiO 2 , ZrO 2 , ZnO, SrO). Since lithium metasilicate has a very high nucleation rate, the challenge of this work step was to reduce the nucleation rate and seek better microstructure control with crystals below 20 ⁇ m size while maintaining a high crystallized fraction.
  • the amount of residual glass was calculated taking into account the expected crystallized fraction for each composition.
  • the composition of the waste glass was designed using Reformix and Sciglass TM software, see Mazurin, O. V-et al. Sciglass 7.4 - Glass Property Information System, http: // www. scass lass. inf ⁇ /. so that it has properties similar to those of Iftio metasilicate crystal as density (2.52 g / cm 3 ) and refractive index (1,6).
  • Table 1 below shows the elaborate compositions.
  • the components SiO 2 and Li 2 O contribute to the formation of lithium metasilicate (Li 2 SiO 3).
  • the meta 01, 02, 03, 06, 08 and 09 compositions were designed to have 80 mol% of lithium metasilicate crystals.
  • Meta 04 and 05 compositions were designed to have 75 mol% of lithium metasilicate crystals.
  • the composition meta 07 was made with a smaller amount of lithium, considering the possibility of formation of only 60% in mol of lithium metasilicate.
  • the remaining components added to the glasses are expected to be secreted during crystallization and to form the residual vitroceramic glass phase, together with the excess SiO 2 added. This assumption was taken into account in the elaboration of the compositions.
  • the Na 2 O, K 2 O, CaO and MgO components are mesh modifiers and are often used as fluxes in silicate glasses. They, together with Li 2 O, contribute to decreasing the melting temperature of the compositions. CaO and MgO components can also act as stabilizers by reducing unwanted devitrification or crystallization during melt cooling.
  • the SrO, ZnO and BaO components are intermediates and may act as modifiers or network formers. They act as stabilizers, reducing devitrification.
  • Al 2 O 3 , ZrO 2 and B 2 O 3 are formers and may contribute to the increase of the chemical durability of waste glass.
  • the presence of Al 2 O 3 was limited in quantities less than 6 mol% to prevent the formation of crystals of the Li 2 O.AI system 2 O 3 .SiO 2 as ⁇ - ⁇ -quartz and espodumeno. Transition metals or rare earth elements may also be used for the production of colored glass ceramics. This embodiment is within the scope of the invention.
  • the melting was performed in the temperature range of 1250 ° C to 1450 ° C for 3 to 4 hours and the obtained glass was poured into a 12mm diameter cylindrical steel mold. Irregular samples were also obtained via splatcooling or pressing of the glass between two metal plates to accelerate its cooling.
  • the samples were annealed at temperatures between 400 - 45 ° C for 120 - 600 min.
  • the annealing temperature being set at 30 ° C below the glass transition temperature of each composition.
  • Tg Glass Transition Temperature
  • Tc Crystallization temperature
  • Tm melt temperature of the crystalline phase
  • the Tg for the compositions is in the temperature range of 440 ° C to 460 ° C, as can be seen in Figure 1, Figure 2 and Figure 3.
  • the metaOI composition has four crystallization peaks, the maximum corresponding to the first peak at a temperature of 614 ° C.
  • Compositions meta02 and meta03 have three crystallization peaks, the maximum corresponding to the first peak at a temperature of 568 ° C and 575 ° C respectively.
  • the meta 04 composition has an intense crystallization peak at 565 ° C and two other mild peaks at temperatures above at e00 ° C.
  • the composition meta 05 presents the most intense crystallization peak of all, for vofta of 584 ° C. Finally, the meta composition is done.
  • compositions present lithium metasilcate as the main crystalline phase.
  • the diversity of the crystallization peaks appear as secondary phases: Li 2 Si 2 O 5, SiO ⁇ LiAl 2) 2> 2 LiAISi 6, CaSiO 3.
  • Long-term heat treatment (above 30min) at temperatures above 800 ° C leads to the transformation of lithium metasilicate (Li 2 SiO 3 ) into lithium disilicate (Li 2 Si 2 O 5 ) and may significantly increase the volume fraction. of the latter. This phase transformation is undesirable since the lithium disilicate phase is not stable, this makes long-term heat treatment at temperatures above 800 ° C prohibitive.
  • Tm occurs around 900 ° C. This enables these materials to be conformed also by the technique of injection molding, provided they are heated to temperatures around 900 ° C.
  • the other compositions have Tm above 1000 ° C.
  • Isothermal and non-isothermal treatments were performed.
  • the samples were inserted into the oven without opening it, this was possible due to the presence of an alumina tube positioned in a small opening in the oven lid.
  • the oven was previously heated and its temperature stabilized. After the required time, the samples were removed and wrapped by an insulating blanket, avoiding their thermal shock rupture.
  • non-isothermal treatments the samples were subjected to a constant heating rate to a given temperature, left at this temperature for the required time and then cooled within the furnace to a cooling rate of approximately 15 ° C / min. This value corresponds to the average free cooling rate of the oven, ie when it is switched off.
  • Two types of non-isothermal treatments were performed: single and double. In the simple treatment the sample was heated to the crystal growth temperature and may or may not be left at this temperature for a certain time and in then cold. In the double treatment the sample is heated to the nucleation temperature, left at this temperature for a certain time, then the sample is heated again to the crystal growth temperature and may remain at this temperature for a certain time, then the sample is cooled. . In general, the range employed in the heat treatments was 455 ° C to 475 ° C for times from 5 min to 180 min for nucleation and 700 ° C-900 ° C for times from 3 min to 30 min for crystal growth.
  • Non-isothermal treatment was employed mainly for making larger pieces ( ⁇ 30x15x4mm 3 ). These parts were used for mechanical tests and in the production of biocos for later machining. The use of this type of heat treatment did not compromise the properties of the vitroceramics or alterations in its visual aspect.
  • the obtained glass ceramics have crystallized fraction above 50% vol., Evaluated by optical microscopy. An average range of crystallized fraction is between 50% vol. and 80% by voice.
  • meta 02 all have lithium metasilicate (Li 2 SiO 3 ) as the main phase.
  • Figure 4 shows the x-ray diffractograms for the meta 01 compositions; 02; 04; 05 treated as described in Table 2. As can be seen from Figure 4, the samples have the cold crystallized fraction as there is no pronounced amorphous halo on X-ray diffractograms.
  • the meta 01 composition has the minor crystalline phase LiAISi 2 O 6 , which may be justified by the high content of AI 2 O 3 in this composition (as shown in Table 1).
  • the meta 02 composition has lithium disilicate (Li 2 Si 2 O 5 ) as the major crystalline phase and the meta 04 and Q5 compositions have Li 2 SiO 3 as the major phase.
  • Table 2 shows some characteristics and properties of the developed glass ceramics, such as heat treatment employed, majority crystalline phase, minority crystalline phases, hardness and fracture toughness by the double twist method, which was applied only to the meta03 composition due to difficulties in sample preparation.
  • the measure represents the average of seven checks on the meta03 composition.
  • the meta06, 08 and 09 compositions were made from minor changes in the AI 2 O 3 and ZrO 2 content of the meta03 composition and are therefore not shown in Table 2 above.
  • the meta 02 composition has 2.5 mol% P 2 O 5 and this component is responsible for inducing the formation of Li 2 Si 2 O 5 in this glass ceramic, see Zheng, X .; Wen, G .; Song, L; Huang, XX Effects of P 2 O 5 and heat treatment on crystallization and microstructure in lithium disilicate glassceramics. Acta Materialia, no. 56, p. 549-558, 2008. Accordingly, the P 2 O 5 content was limited to amounts of less than 2 mol% in the following compositions.
  • the meta03 composition showed only Li 2 SiO 3 in isothermal treatments, high translucency when compared to the other compositions and was therefore considered as improved composition. in this first stage of development.
  • This glass ceramic has been subjected to more detailed characterization and machining tests.
  • meta-03 glass ceramics When subjected to isothermal treatments (single or double), meta-03 glass ceramics may present only the crystalline phase lithium silicate phase, as shown in the diffractograms of Figure 5. However, for larger pieces it is necessary to the sample is cooled slowly and this can favor the formation of other crystalline phases, or conversion lithium metasilicate (Li 2 SiO 3), which is metastable, lithium disilicate (U 2 Si 2 O s).
  • the crystallized fraction was determined by X-ray diffraction using a Cu-filament diffractometer (Rigaku Ultima IV).
  • the diffractograms were performed in the 2 ⁇ range of 10 ° -120 ° in stepscan mode with an angular range of 0.02 ° and 1 s counting time.
  • the weight fraction of the phase contained in the sample was determined by Rietveld refinement of the X-ray diffractogram.
  • the meta 03 glass ceramic treated at 460 ° C / 5min; 800 ° C / 3min and cooled to 15 ° C / min, presents the Iftio metasilicate crystalline phase (Li 2 SiO 3 ), its volume crystallized fraction determined by X-ray diffraction and Rietveld refinement is 65 ⁇ 5%. vol. It was also determined for this glass ceramic 15 ⁇ 1% vol. iftio disilicate (Li 2 Si 2 O 5 ), 2% vol. of AIPO 4 and 18 ⁇ 5 vol. of residual glass, This heat treatment was considered in the following characterizations, as it allows obtaining larger pieces.
  • Figure 6 shows the microstructure obtained in the meta 03 glass ceramic treated at 460 ° C / 5min; 800 ° C / 3min and cooled to 10 ° C / min. It has plate-shaped Li 2 SiO 3 crystals that can reach a length of up to 20 ⁇ m, as seen in Figure 6Error! Reference source not found.A. This type of crystal favors part machining, see H ⁇ land.W .; Rheinberger, V .; Apei, E .; Van'tHoen, C. Principles and phenomena of bioengineering with glass-ceramics for dental restoration. Journal of the European Ceramic Society, no. 27, v. 2-3, p. 1521-1526, 2007.
  • the microstructure obtained from the vitroceramic material object of the invention is very similar to that of the commercial vitroceramic Macor, whose appearance resembles stacked playing cards and is therefore known by the name "house of cards", see Hoiland, W. ; Beall, G. Glass-ceramic technology. Westerville, Ohio: The American Ceramic Society, 2002, p. 205.
  • the glass phase cannot be seen in Figures 6A and 6B because it was completely removed by the severe acid attack.
  • the main advantage of this material over Macor is that it is not necessary to incorporate fluorine into the glass composition, which generally produces HF vapor during melting. HF is extremely harmful to mucous membranes and harmful to the environment.
  • Macor vitroceramically has a fracture toughness of only 1.5 MPa.m 1/2 , see ⁇ http://psec.uchicago.edu/ceramics/MACOR%20Data%20Sheet.pdf>. Accessed on: 01/19/2015.
  • Figure 6C shows how Li 2 SiO 3 crystals are interconnected. This favors the creation of rough fracture surfaces ( Figure 6D) and consequently higher fracture toughness of this material. This microstructure guarantees good machinability for this glass ceramic.
  • the size of the crystals can be controlled by heat treatment, in particular by increasing nucleation time.
  • the Error! Reference source not found.
  • Figure 7 shows a micrograph of the nucleated meta03 vitroceramic at 450 ° C for 3 h and subjected to non-isothermal treatment for crystal growth, having been heated at 20 ° C / min to 800 ° C and freely cooled to room temperature. Plate-shaped crystals of size less than 5 ⁇ m are observed. The reduction in size of crystals may favor the increase of mechanical resistance of vitroceramic.
  • Hardness (H) and elastic modulus (E) were determined by instrumented indentation technique.
  • the test equipment was a Berkovich-tipped MTS Systems Corporation XP Nanoindenter XP. The tests were performed with 50% controlled humidity and room temperature of 22 ⁇ 0.5 ° C. A 400 mN load was employed using 8 load-unload cycles. Loading and unloading time was 10 s and the charge was kept constant for a period of 15 s. For each sample 36 indentations were performed separated by a distance of 150 ⁇ and the average value of the obtained results was adopted. For meta03 vitroceramic, the measured hardness value was 7.0 ⁇ 0.5 GPa and elastic modulus was 120 ⁇ GPa, considered very high for vitroceramic materials.
  • Figure 8 shows the values obtained for hardness and elastic modulus as a function of the contact depth of the indentator tip.
  • Fracture toughness was estimated by mechanical doubling or double torsion testing. A total of 7 samples of the meta 03 composition were tested and the average value obtained was 3.5 ⁇ 0.5 MPa.m 1/2
  • the biaxial flexural strength was determined by ISO 6872 and the value obtained for heat treated meta 03 vitroceramic at 460 ° C / 5min and 800 ° C / 3min was 170 ⁇ 35 MPa.
  • the developed vitroceramics are white and translucent.
  • Translucency is an important property for some of the possible applications for this material, such as restorations, dentures and dental veneers.
  • Figure 11 shows the transmittance in the visible spectrum region for the meta 03 glass ceramic submitted to two different heat treatments, the first (sample 1 ⁇ treated at 800 ° C for 3 min with 0.70mm thickness and the second (sample 2). treated at 458'C for 5 min and 800 ° C for 3 min with 0.68mm thickness.
  • Metal vitroceramics have an average transmittance between 15 and 20% in the spectrum region from 400 to 700 nm Visually, the verified translucency is acceptable. and similar to that of natural teeth and commercial materials such as emax Press, see IvoclarVivadent - Catalog Lithium disiiicate: the future of all-ceramic dentistry.
  • Figure 12 shows the transmittance for the high translucency e-Press commercial material (A1). Although the thickness of the material is slightly different, one can get an idea of the transmittance in these materials, values are generally below 18% for thicknesses around 1 mm.
  • the translucency of the developed material can be controlled by minor changes in glass composition or heat treatment to obtain glass ceramic.
  • Figure 13 shows the transmittance in the visible spectrum region for the meta 04 and 05 vitroceramics.
  • the meta 04 and meta 05 vitroceramics were heat treated at 475 ° C for 5 min and 950 ° C for 15 min and after polishing the value of their thickness was 0.67 mm and 0.60 mm respectively. It is observed that the meta 05 vitroceramic has greater transmittance in the visible region and that the meta 04 vitroceramic behaves similarly to the meta 03 vitroceramic.
  • a 4% by volume acetic acid solution was prepared. Samples with a total surface area of 30cm 2 were inserted into a teflon bottle containing 100ml of acetic acid solution and left for 16h at 80 ° C. Samples were weighed before and after the assay and then the amount of mass lost in micrograms per square centimeter of sample was calculated and will be referred to herein as chemical solubility.
  • the meta 03 glass ceramic exhibits chemical solubility of 215 ⁇ 31 ⁇ g / cm 2 when treated at 460 ° C / 5min and 800 ° C / 3min.
  • the chemical solubility required by ISO 6872 varies according to clinical recommendation and may range from 100 ⁇ g / cm 2 to 2000 ⁇ g / cm 2 .
  • the same meta 03 composition treated at 460 ° C / 3h and 800 ° C / 3min has a chemical solubility of 78 ⁇ 24 Mg / cm 2 , as shown in Table 3 below.
  • the developed material could be applied, for example, as aesthetic dental vitroceramics to cover metal or a ceramic substructure, as it has a chemical solubility of less than 100 ⁇ g / cm 2 .
  • Table 4 there are several other applications in the dental area, where the developed glass ceramic could be used. These applications include ceramic substructures or prostheses that are previously coated with ceramic enamel; These enamels guarantee the color adjustment and aesthetic appeal of the prosthesis.
  • compositions with higher alumina content (meta 06 and 08) and zirconia (meta 09 and 10) were prepared.
  • zirconia was effective, and the chemical solubility of the meta 09 composition, subjected to the same heat treatment as the meta 03 composition, was 175 ⁇ 29 ⁇ / cm 2 .
  • This result is still above the value required by the standard for application as aesthetic glass ceramic, however the results indicate that this property can be controlled by heat treatment of the material.
  • Increasing the nucleation time to 180 min enabled greater chemical durability for the developed material (meta 03).
  • the meta-vitroceramic has a linear thermal expansion coefficient (CET) of 13.6 x 10 -6 ° C -1 , determined by a Netzsch DIL 402 PC dilatometer in the temperature range of 50-400 ° C with a heating rate. at 5 ° C / min.
  • the samples had dimensions of 35x2x2 mm 3.
  • Figure 14 shows the expansion of this material as a function of temperature. It is observed that the use temperature of the meta 03 material extends to 450 ° C, without deformation of the material by viscous flow.
  • the developed glass ceramics were subjected to cytotoxicity assays in ftbroblast culture. The following samples were evaluated: glass ceramic meta 03; vitroceramics e.max Press by Ivoclar (reference) and alumina.
  • Figure 15 shows the cell viability of the analyzed samples. The tests show that the meta 03 glass ceramic presents very similar behavior to the samples of commercial glass ceramic e.max Press (Ivoclar) and alumina, being not toxic to the organism.

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Abstract

L'invention concerne des vitrocéramiques usinables à haute ténacité à la rupture, contenant du métasilicate de lithium comme phase principale (>50% en volume et juqu'à 80% en volume) pour permettre l'usinage de la vitrocéramique et la production de pièces à haute complexité dimensionnelle. Les vitrocéramiques usinables présentent une résistance à la fracture d'au moins 3,5 ± 0,5 MPa.m1/2 selon le procédé de torsion double. Ces vitrocéramiques usinables présentent d'excellentes propriétés d'usinabilité et de translucidité, (transmittance dans la région du spectre visible de 10% à 20%) ainsi qu'une bonne durabilité chimique (solubilité dans de l'acide acétique <250μg/cm2), et sont exemptes de cytotoxicité. Lesdites vitrocéramiques usinables sont utiles pour la confection de pièces céramiques de dimensions complexes par usinage, telles que les pièces utilisées dans des applications odontologiques.
PCT/BR2017/000087 2016-08-05 2017-08-04 Vitrocéramiques usinables à haute ténacité à la rupture, et utilisation de celles-ci WO2018023181A1 (fr)

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BR102016018179-8A BR102016018179B1 (pt) 2016-08-05 Vitrocerâmicas usináveis de alta tenacidade à fratura e uso das mesmas
BRBR102016018179-8 2016-08-05

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7452836B2 (en) * 2005-02-08 2008-11-18 Ivoclar Vivadent Ag Lithium silicate glass ceramic
US20110009254A1 (en) * 2003-08-07 2011-01-13 Ivoclar Vivadent Ag Lithium Silicate Materials
EP2765979A2 (fr) * 2011-10-14 2014-08-20 Ivoclar Vivadent AG Vitrocéramique et verre en silicate de lithium, ayant un oxyde métallique pentavalent
US20150140513A1 (en) * 2012-05-11 2015-05-21 Ivoclar Vivadent Ag Pre-sintered blank for dental purposes
US20150374465A1 (en) * 2013-02-12 2015-12-31 Ivoclar Vivadent Ag Blank for dental purposes
US20150374589A1 (en) * 2013-04-15 2015-12-31 Ivoclar Vivadent Ag Lithium silicate glass ceramics and lithium silicate glass containing cesium oxide
US20160051349A1 (en) * 2013-04-15 2016-02-25 Ivoclar Vivadent Ag Lithium silicate glass ceramic and glass with rubidium oxide content

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110009254A1 (en) * 2003-08-07 2011-01-13 Ivoclar Vivadent Ag Lithium Silicate Materials
US7452836B2 (en) * 2005-02-08 2008-11-18 Ivoclar Vivadent Ag Lithium silicate glass ceramic
EP2765979A2 (fr) * 2011-10-14 2014-08-20 Ivoclar Vivadent AG Vitrocéramique et verre en silicate de lithium, ayant un oxyde métallique pentavalent
US20150140513A1 (en) * 2012-05-11 2015-05-21 Ivoclar Vivadent Ag Pre-sintered blank for dental purposes
US20150374465A1 (en) * 2013-02-12 2015-12-31 Ivoclar Vivadent Ag Blank for dental purposes
US20150374589A1 (en) * 2013-04-15 2015-12-31 Ivoclar Vivadent Ag Lithium silicate glass ceramics and lithium silicate glass containing cesium oxide
US20160051349A1 (en) * 2013-04-15 2016-02-25 Ivoclar Vivadent Ag Lithium silicate glass ceramic and glass with rubidium oxide content

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