WO2009156493A1 - Constructions dentaires et procédés pour les préparer - Google Patents

Constructions dentaires et procédés pour les préparer Download PDF

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Publication number
WO2009156493A1
WO2009156493A1 PCT/EP2009/058010 EP2009058010W WO2009156493A1 WO 2009156493 A1 WO2009156493 A1 WO 2009156493A1 EP 2009058010 W EP2009058010 W EP 2009058010W WO 2009156493 A1 WO2009156493 A1 WO 2009156493A1
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WIPO (PCT)
Prior art keywords
ceramic
glass
glass ceramic
dental
veneering
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PCT/EP2009/058010
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English (en)
Inventor
Richard Van Noort
Sarah Pollington
Original Assignee
University Of Sheffield
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Publication of WO2009156493A1 publication Critical patent/WO2009156493A1/fr

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    • 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
    • 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
    • A61C13/0003—Making bridge-work, inlays, implants or the like
    • 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
    • C03C10/16—Halogen containing crystalline phase
    • 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
    • C03C4/00—Compositions for glass with special properties
    • C03C4/0007—Compositions for glass with special properties for biologically-compatible glass
    • C03C4/0021—Compositions for glass with special properties for biologically-compatible glass for dental use
    • 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
    • A61C13/08—Artificial teeth; Making same
    • A61C13/083—Porcelain or ceramic teeth
    • 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
    • A61C5/70—Tooth crowns; Making thereof
    • A61C5/77—Methods or devices for making crowns

Definitions

  • the present disclosure relates to new glass ceramic materials in particular for use in the preparation or manufacture dental constructs.
  • the present disclosure relates also to dental constructs comprising such glass ceramic materials and to methods of making dental constructs using such glass ceramic materials.
  • Dental constructs to which the present disclosure is applicable include dental restorations, fixed prostheses and the like. More especially, suitable dental constructs include crowns, onlays, inlays, bridges and the like. More especially, dental constructs to which the present disclosure is applicable are all-ceramic constructs, in particular those including an inner part (a
  • core of a first ceramic material and an outer aesthetic layer, in particular a veneering ceramic.
  • the glass ceramic materials of the present disclosure are also suitable in particular as core materials for dental crowns.
  • the present disclosure further relates to glass ceramic materials, in particular for dental constructs which can be processed (e.g. shaped) using CAD/CAM (computer aided design/computer assisted manufacture) procedures.
  • the oral environment presents challenges for materials used for dental constructs.
  • the materials used should preferably:
  • solubility must be below
  • the material should be able to withstand chemical attack in the oral environment, such as from contact with saliva, fluoride applications (toothpaste and mouthwashes) and low pH beverages; ii. be sufficiently strong to resist the forces of mastication; iii. be capable of being formed into shapes and forms compatible with human anatomy, preferably without the use of complex and expensive equipment; iv. have desirable aesthetic qualities, including the ability to colour match to a subject's natural teeth, and a degree of translucency similar to that of natural teeth; v. be substantially non-moisture absorbing and substantially non-staining; vi. have wear characteristics similar to those of natural teeth.
  • Glass-ceramics are typically defined as polycrystalline solids prepared by the controlled crystallisation of glasses. Glasses are melted, fabricated to shape, and then converted by heat treatment to a partly (or predominantly) crystalline ceramic. Generally, crystallisation is achieved when the glass is subjected to a carefully regulated heat treatment regime which results in the nucleation and growth of a crystal phase within the glass matrix.
  • a two-stage heat treatment process (often referred to as "ceramming"), comprising a nucleation and crystallisation step, is commonly employed for the preparation of glass-ceramics. The nucleation stage involves heating the glass from room temperature to the nucleation temperature and is used to create a large number of small crystals for efficient nucleation.
  • the temperature of the glass is increased at a controlled rate, sufficiently slowly to allow crystal growth to occur without deformation of the glass.
  • the length of time the material is held at the growth temperature depends on the degree of crystallinity that is required in the final glass ceramic material.
  • the glass ceramic material is then cooled back down to room temperature. Generally, a high rate of nucleation and a low crystal growth rate are needed to achieve a fine grained ceramic since many more sites are provided for crystal growth. Proper control of the crystallisation heat treatment is necessary to ensure the nucleation of a sufficient number of crystals and their growth to an effective size.
  • the properties of glass ceramic materials depend on both their chemical composition and the microstructure.
  • the bulk chemical composition controls the ability to form a glass and its degree of workability.
  • the microstructure of is important in determining many of the mechanical and optical properties (such as fracture toughness and strength) and can promote or diminish the role of the key crystals in the glass-ceramic. Consequently, the microstructure is dependent on the use of a correct and optimal heat treatment schedule.
  • the crystals that form within the matrix during heat treatment can vary significantly depending on the glass composition.
  • the phase evolution in canasite-based compositions (including fluorcanasite) is complex and small modifications in composition radically change the crystallised product and fundamentally alter the mechanism of nucleation.
  • Chain silicates are polymeric crystals in which single or multiple chains of silica tetrahedra form the structural backbone.
  • modified chain silicate compositions e.g. enstatite, potassium fluorrichterite and canasite
  • can have high fracture toughness 3-5 MPa m
  • bending strength 200-300MPa
  • Fluorcanasite (Ca 5 K 2-3 Na 3-4 Si I2 O 30 F 4 ) is a synthetic double chain silicate glass-ceramic which can be synthesised from glasses close to its stoichiometry. Fluorcanasite displays a combination of high flexural strength and fracture toughness in comparison with currently available resin-bonded glass-ceramic dental restorative systems. In addition, fluorcanasite, unlike many currently known high strength dental ceramics, has a surface that could be bonded with an adhesive composite resin luting agent. However although fluorcanasite is known to have good mechanical properties, a significant disadvantage hitherto has been its high chemical solubility and this has been a key limiting parameter for its use as a dental material.
  • Resin-bonded all-ceramic dental restorations require for their success in use that a durable and reliable bond is obtained, which must successfully integrate all parts of the restoration into one coherent structure.
  • this bond has typically been created by: (1 ) micromechanical retention by hydrofluoric acid etching and/or grit blasting, and; (2) chemical bonding by a silane coupling agent.
  • Etching the inner surface of a restoration with hydrofluoric acid followed by the application of a silane coupling agent is a well known and recommended method to increase the bond strength.
  • Shimada et al in "Micro-shear bond strength of dual-cured resin cement to glass ceramics.
  • Reasons for seeking to bond components of a dental reconstruction without recourse to a hydrofluoric acid etching step during the procedure may include: (1 ) hydrofluoric acid is a highly toxic chemical, representing a potentially serious health hazard; (2) it has been reported that hydrofluoric acid etching of silica-based ceramics produces insoluble silica-fluoride salts, which can remain as by-products on the surface (Shimada et al, ibid). If not removed, these by-products can interfere with the bond strength to the resin. However, although elimination of HF from the bonding procedure would be highly advantageous, this would only be possible in practice if the silane bond between the glass ceramic material and the adjacent element of the dental reconstruction can be shown to be adequate.
  • Fracture resistance of the ceramic-resin bond is believed to be controlled primarily by the microstructure and surface treatment of the ceramic. Therefore, it is highly desirable that an optimal bonding protocol for securing the ceramic and the resin is developed. Because fluorcanasite is a chain silicate glass-ceramic, the inventors suggest herein that it is possible to achieve a reliable bond using a silane coupling agent and resin cement and furthermore that because of the fine grain, acicular microstructure of fluorcanasite, it may be possible to eliminate the hydrofluoric acid etching stage from the cementation procedure.
  • the preparation process for a glass ceramic material may include an initial heating stage to promote crystal nucleation and a second heating stage to promote crystal growth.
  • the materials used for forming the glass ceramic are formed into the desired shape of the dental construct before such a heating procedure and it is therefore desirable that materials are dimensionally stable during such heating stages so that, for example, excessive shrinkage is avoided.
  • a dental construct is formed from more than one material (such as an inner core material and an outer aesthetic veneer) it is highly desirable that the coefficients of thermal expansion of the respective materials are matched, in order to avoid cracking or fracturing due to stresses induced by different rates of thermal expansion between the materials.
  • US 4 386 162 describes glass ceramics wherein the predominant crystal phase is canasite having a composition, in weight percent on the oxide basis of:
  • EP 0 641 556 describes glass ceramic "biomaterial" which may be used as bone implants or partial replacements.
  • the materials contains F-canasite and F-apatite crystals and is derived from a glass containing:
  • Glass ceramic materials based on lithium disilicate are also known for use in the fabrication of dental restorations.
  • One example is described in US 6 342 458 which describes a glass ceramic comprising (in wt%):
  • AI 2 O 3 +La 2 O 3 amount to 0.1 to 7 wt% and (b) MgO+ ZnO amount to 0.1 to 9 wt%.
  • a glass ceramic material having a predominantly fluorcanasite structure comprising (and preferably consisting essentially of, more preferably consisting exclusively of), subject to any incidental impurities:
  • the glass ceramic of the disclosure has the general formula:
  • the glass ceramic material comprises essentially in mol%:
  • Preferred glass ceramic materials have a fracture toughness in the range of from 1 to 6 MPa m /2 , more preferably from 2 to 5MPa m /2 and especially from 3 to 4.5.MPa m /2 .
  • the glass-ceramic materials have a solubility in the range of from 2000 to 100 ⁇ gcm "2 ., more preferably from 1500 to 100 ⁇ gcm "2 and especially from 1000 to 100 ⁇ gcm "2 .
  • Solubilities herein are determined in accordance with ISO 6872:1999 Dental Ceramic Standard. This Standard involves subjecting the test ceramic material to 16 hours in 4% acetic acid solution at 80 0 C.
  • Preferred glass ceramic materials have a total transmittance in the range of 80 to 30%, more preferably from 80 to 50% and especially from 80 to 65%.
  • a dental construct comprising a glass ceramic material of the first aspect of the disclosure.
  • the dental construct is a shaped dental construct such as a dental crown, or a part of a dental crown.
  • the dental construct is a dental restoration for the posterior region of oral the cavity, preferably a posterior crown.
  • the dental construct may be the core of a dental crown.
  • Dental constructs comprising the glass ceramic material according to the disclosure are especially suitable for securing to an underlying structure (such as a prepared residual portion of a tooth) by resin bonding in particular using a commercial composite resin luting system.
  • an all ceramic dental construct comprising a core of a glass ceramic material as defined in the first aspect of the invention and a veneering ceramic.
  • the dental construct comprises a dental restoration for the posterior region of oral the cavity, preferably a posterior crown.
  • the dental construct comprises a silane coupling agent applied to the glass ceramic core and a resin luting agent bonding the core to the veneer.
  • the glass ceramic of the core and the veneering ceramic have a substantially matched coefficients of thermal expansion (CTEs). More especially the CTE values of the glass ceramic of the core and the veneering ceramic differ by not more than 2ppm/°C, preferably not more than 1 ppm/°C.
  • a glass composition comprising:
  • ceramming the composition and machining to form the dental construct It is a particular advantage of the method that only a single machining stage is required, in contrast to some prior art procedures which require machining both before and after the ceramming stage.
  • the dental construct comprises an all-ceramic dental restoration, and the method further comprises applying a veneering ceramic to the glass ceramic body.
  • the veneering ceramic is applied to the glass ceramic body without any intervening physical surface modification step of the glass ceramic body. More especially the veneering ceramic is applied to the glass ceramic body without any intervening grit blasting step and/or without any intervening chemical etching step, such as a hydrofluoric acid etching step
  • the ceramming step includes an initial nucleation stage at a first temperature and a subsequent crystallisation stage at a higher, second, temperature.
  • the first temperature is in the range of from about 500 to 650 0 C.
  • the second temperature is in the range of from about 800 to 900 0 C.
  • the inventors suggest that the individual components of the glass ceramic material according to the present disclosure have the following properties and functions:
  • SiO 2 acts as a network former.
  • Network formers form glasses when melted and cooled because of their ability to build up continuous three dimensional random networks.
  • Na 2 O, K 2 O, CaO act as network modifiers.
  • Network modifiers are incapable of building up a continuous network and function to partly disrupt the network structure through the introduction of ionic bonds.
  • the metal ions involved tend to form non-directional ionic bonds with oxygen atoms, resulting in the formation of non-bridging oxygens in the structure.
  • the effect of network modifiers is generally to reduce the viscosity of the glass and to increase the coefficient of thermal expansion
  • CaF 2 acts as a nucleation agent for the crystallisation of fluorcanasite and plays an important role in controlling types of crystalline phase formed and microstructure of the fluorcanasite. Generally, additional of excess CaF 2 to the glass ceramic composition promotes improved nucleation and a finer grain size. If the fluorine content is too low nuclei formation and crystal formation may be inhibited. On the other hand, if the fluorine content is too high precipitation of CaF 2 may occur. ZrC> 2 (zirconia) addition is believed to aid CaF 2 in the crystallisation of fluorcanasite, to produce a glass-ceramic with canasite (rather than frankamenite) as the dominant phase.
  • FIG 1 shows the mean surface roughness (Ra) measurements of the fluorcanasite and lithium disilicate glass-ceramics following different surface treatments (Example 2);
  • Figure 2 shows SEM images of fluorcanasite and lithium disilicate demonstrating different surface finishes (Example 2);
  • Figure 3 shows mean microtensile bond strength and standard deviation for ceramic- composite bond with different surface treatments (Example 2);
  • Figure 4 is an example of typical SEM micrograph depicting cohesive failure in the luting resin.
  • Figure 5 shows an SEM image of adhesive failure at the interface between the luting resin and ceramic.
  • a fluorcanasite based glass ceramic material having the formula shown in the Table 1 was formed by the following method
  • a veneering ceramic (50%feldspar/50% high leucite) with matched coefficient of thermal expansion (CTE) was then applied to the core structure and fired in a vacuum furnace at 940 0 C.
  • the resulting glass ceramic material had the properties indicated in Table 2:
  • This material would not melt to form a clear glass - devitrification occurred with calcium fluoride and hence a cloudy glass was formed.
  • the ceramic blocks were duplicated in composite resin (Spectrum") and cemented together with a resin luting agent (Variolink II ® ). Thirty microbars per group (1.0 x 1.0 x 20mm) were obtained and subjected to a tensile force at a crosshead speed of 0.5 mm/min using a universal testing machine until failure. The mode of failure was determined using scanning electron microscopy. Each bonding procedure was assessed for durability by storing in water at 100 0 C for 24 hrs. Statistical analyses were performed with ANOVA and Tukey's test (P ⁇ 0.05). Procedural details are set out below in "Detailed Procedure" and a fuller discussion of the results follows thereafter.
  • the fluorcanasite glass ceramic when preparing a dental construct, should be left as machined, to the exclusion of any physical or chemical treatment which materially affects the physical nature of the glass ceramic surface, more especially to the exclusion of any grit blasting or acid etching treatment.
  • the machined surface is, however, preferably directly treated with a silane coupling agent.
  • CAD/CAM machinable glass-ceramic core materials were employed in this example; an experimental fluorcanasite glass-ceramic (University of Sheffield) and a commercial lithium disilicate glass-ceramic (e.max CAD, batch number JO8179, Ivoclar Vivadent AG, Schaan, Liechtenstein).
  • a surface roughness profile was determined for each of the groups using a profilometer (Mitutoyo Surftest 301 , Mitutoyo America Corp, Aurora, III).
  • a diamond stylus (5 ⁇ m radius) was used under a constant measuring force of 3.9N.
  • the instrument was calibrated using a standard reference specimen, and then set to travel at a speed of 0.1 mm/s with a range of 600 ⁇ m during testing.
  • the 1 ⁇ m finish produced the smoothest surface profile for both the fluorcanasite and the lithium disilicate glass-ceramic. Machining in conjunction with grit blasting created the roughest surface for the fluorcanasite glass-ceramic whereas with the lithium disilicate glass-ceramic, this was attained by machining alone.
  • the mean surface roughness values and standard deviation are presented in Table 7 and Figure 1. A significant difference was noted between the surface finish of machining and grit blasting between the fluorcanasite and lithium disilicate glass-ceramics. HF etching reduced the surface roughness in comparison to the grit blasted surfaces with both glass-ceramics. Table 7: Mean surface roughness (Ra) and SD for the different surface treatments.
  • the 1 ⁇ m finish consisted of an extremely low frequency with virtually no amplitude defects.
  • the machined surface there was an increased frequency of irregular amplitude defects varying from +13 to -12 ⁇ m for the lithium disilicate glass-ceramic in comparison to a range of +7 to -7 ⁇ m for the fluorcanasite glass-ceramic.
  • the grit blasted surface With the grit blasted surface, a much higher frequency of irregular amplitude defects was found with the fluorcanasite glass-ceramic, with a range of +22 to -22 ⁇ m.
  • the lithium disilicate glass-ceramic showed a much lower frequency of amplitude defects with a range of +4 to -6 ⁇ m.
  • the HF etched surface showed similar results for both ceramics.
  • the irregular amplitude defects had a range of +9 to -10 ⁇ m for the fluorcanasite and +5 to -8 ⁇ m for the lithium disilicate glass-ceramic.
  • the two glass-ceramics have different microstructures and varying appearances were observed with the surface treatments (Figure 2).
  • the 1 ⁇ m finish was smooth and polished with minimal surface defects. Machining of the fluorcanasite glass-ceramic opened up the structure and blade-like crystals were easily seen, creating an irregular surface.
  • the lithium disilicate glass-ceramic had a rough appearance after machining but without prominent crystals.
  • the grit blasting treatment had destroyed the crystal structure of the fluorcanasite glass-ceramic and areas were gouged out resulting in crevices and a crater-like appearance.
  • the lithium disilicate glass-ceramic showed an irregular rippled appearance caused by the grit blasting but with no evidence of crevices.
  • the 15 blocks of each ceramic were randomly assigned to three groups which received the following surface treatments: (i) Machined finish using a 60 ⁇ m diamond bur (Henry Schein, Germany). This surface finish was used to simulate the machining process of the CAD/CAM technology.
  • a silane coupling agent (Monobond-S, batch no J14325, Ivoclar Vivadent AG, Schaan, Liechtenstein) was then applied to each group with a brush, left undisturbed for 1 min and then dried with an air stream.
  • the ceramic and composite resin blocks were then joined as pairs using a composite resin luting system (Variolink II, batch no J17818, Ivoclar Vivadent AG, Schaan, Liechtenstein) according to the manufacturer's instructions and light polymerised with a standard halogen light (LCU, Bayer Dental, Leverkusen) for four 40 sec periods at right angles to each other.
  • the specimens were stored in distilled water for 24 hr.
  • each block was longitudinally cut into a series of 1 mm thick slabs. The sectioning continued until 1 mm remained to keep the specimen in a fixed position. The ceramic-composite block was then rotated 90° and the procedure repeated. Twelve to fourteen bars approximately 1.0 mm 2 in cross-section ("microbars") were obtained from each block. The peripheral slices were discarded in case the results could be influenced by either excess or insufficient amount of resin cement at the interface. Specimens were obtained directly from the cutting machine, that is, in a non- trimmed state. Neither polishing nor finishing was performed.
  • Each microbar was glued with a cyanoacrylate adhesive (Zapit, CA, USA) to a jig designed to transmit purely tensile forces when mounted on a universal loading machine (Lloyds LRX tensometer, Lloyds Instruments, UK). Bending forces were avoided by gluing specimens in the most parallel position possible and in contact with the jig.
  • the tensile load (100N) was applied at a crosshead speed of 0.5 mm/min until failure. The load at failure in Newtons was recorded, and the fragments of the specimen were carefully removed from the fixture with a scalpel blade.
  • the cross- sectional area at the site of fracture was measured to the nearest 0.01 mm with a digital calliper (Mitutoyo, Tokyo, Japan) in order to calculate the bond strength at failure in MPa.
  • the fractured surfaces were examined by optical microscopy (Bausch and Lomb, USA) and scanning electron microscopy (Philips XL-20) to determine the type of failure, which was classified as adhesive, cohesive or mixed within any of the substrates or interfaces.
  • the fractured surfaces were gold coated (Evaporation unit, Edwards, UK) prior to examination.
  • Table 8 Mean microtensile bond strength data for ceramic-composite bond with different surface treatments. Groups with different superscript letters indicate significant differences (P ⁇ 0.05).
  • the surface treatment methods which afforded the highest microtensile bond strengths were also assessed for bond durability. Thirty microbars of the fluorcanasite and lithium disilicate glass-ceramic, with surface treatments of machined and machined plus HF etching respectively, were fabricated as described before. The specimens were then stored in distilled water at 100 0 C (boiling water) for 24 hours using an extraction apparatus. After a 30 min drying period, the microbars were subjected to the same microtensile bond strength test. The data were analysed using ANOVA with Tukey's multiple comparison tests. The software programme used was SPSS for Windows, version 14.0, SPSS Inc, Chicago, III. The results were considered significant for P ⁇ 0.05.
  • the mean bond strength values, standard deviations and for the microtensile bond strength testing following 24 hours in boiling water are presented in Table 9.
  • the fluorcanasite glass-ceramic achieved a significantly higher mean microtensile bond strength value of 15.23 MPa in comparison to 12.29 MPa for the lithium disilicate glass- ceramic (P ⁇ 0.05).
  • the mode of failure was cohesive in the luting resin whereas with the lithium disilicate glass-ceramic, 75% of the failures were cohesive in the luting resin and 25% were classified as adhesive failure at the interface between the ceramic and the luting resin (Table 9).
  • Table 9 Mean microtensile bond strength data for ceramic-composite bond following 24 hours in boiling water. Groups with different superscript letters indicate significant differences (P ⁇ 0.05).
  • the fluorcanasite discs were core drilled and sectioned using a rotary diamond cutting machine (LECO VC-50, LECO Corporation, Michigan, USA) with a diamond wafering blade (Buehler, Illinois, USA) from the glass, cerammed at 550 0 C for 2 hrs and 840 0 C for 2 hrs and subsequently veneered with the a veneering ceramic having a suitably matched CTE.
  • the lithium disilicate discs were similarly core drilled, sectioned and heated treated according to the manufacturer's instructions as set out in section Table 10 below. These discs were then veneered with the fluoroapatite ceramic at 750 0 C. Digital callipers and a silicone mould were used to standardise these bilayered discs and ensure the thickness of the veneering ceramic was 0.7mm.
  • a maxillary upper first molar tooth (Frasaco, Tettnang, Germany) was prepared with 1.0mm axial, 1.5mm occlusal reduction and a 90° shoulder preparation with a rounded internal line angle.
  • An impression of this preparation was taken using polysiloxone impression material (Aquasil, Dentsply DeTrey GmbH, Konstanz, Germany) and then the impression was cast using a CAD/CAM compatible refractory die material (CamBase, Sirona Dental Systems GmbH, Bensheim, Germany).
  • the resulting model was scanned using the inEos and Cerec inLab system (Sirona Dental Systems GmbH, Bensheim, Germany) and a coping was designed using the software programme (inLab V2.90). All of the copings were milled from the same design and subsequently veneered with the appropriate matched veneering ceramic.
  • the thickness of the veneering ceramic was standardised by the use of digital callipers and silicone moulds. The cooling protocols used following firing were also standardised.
  • the mean ⁇ T value represents the temperature difference required to produce a failure in the ceramic.
  • Table 1 1 ⁇ T values that resulted in failure.
  • the fluorcanasite glass-ceramic system in both disc and crown form, greatly outperformed the lithium disilicate glass-ceramic system (P ⁇ 0.05).
  • the fluorcanasite glass-ceramic discs had ⁇ T values ranging from 230-270 0 C while the lithium disilicate glass-ceramic ranged from 190-240 0 C.
  • the crown system With the crown system, the difference was even more noticeable, with a ⁇ T values of 370-450 0 C for the fluorcanasite glass-ceramic but only 190-230 0 C for the lithium disilicate glass-ceramic system.
  • the ⁇ T values of fluorcanasite glass-ceramic crowns were significantly higher than the other 3 groups (P ⁇ 0.05). There was no statistically significance difference between the two lithium disilicate glass-ceramic groups.
  • the glass ceramic materials of the present disclosure has excellent properties of strength, colour, insolubility and low thermal expansion and, more especially, translucency which make the materials especially suitable for use as dental constructs such as dental crowns and the like.
  • the comparative examples show that even small compositional differences can result in significant loss of desired properties.

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Abstract

L'invention concerne une construction dentaire comprenant un matériau de vitrocérame comprenant, en % molaire : SiO2 62-75, Na2O 5,5-6,5, K2O 5,0-6,0, CaO 11,5-12,5, CaF2 9,0-11,0, ZrO2  <3,0.
PCT/EP2009/058010 2008-06-25 2009-06-25 Constructions dentaires et procédés pour les préparer WO2009156493A1 (fr)

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GB0811616A GB2461278A (en) 2008-06-25 2008-06-25 Dental constructs comprising glass ceramic with fluor-canasite structure
GB0811616.2 2008-06-25

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Cited By (4)

* Cited by examiner, † Cited by third party
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KR101141744B1 (ko) 2009-11-30 2012-05-09 한국세라믹기술원 치아용 고강도 세라믹 블록 및 그 제조방법
KR101141750B1 (ko) * 2009-11-30 2012-05-09 한국세라믹기술원 치과용 인공 치아의 제조방법
CN113248153A (zh) * 2021-05-26 2021-08-13 福州瑞克布朗医药科技有限公司 二硅酸锂玻璃陶瓷及其制备方法和应用
CN115028364A (zh) * 2022-06-07 2022-09-09 山东国瓷功能材料股份有限公司 玻璃陶瓷、其制备方法及牙齿修复材料

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KR101141744B1 (ko) 2009-11-30 2012-05-09 한국세라믹기술원 치아용 고강도 세라믹 블록 및 그 제조방법
KR101141750B1 (ko) * 2009-11-30 2012-05-09 한국세라믹기술원 치과용 인공 치아의 제조방법
CN113248153A (zh) * 2021-05-26 2021-08-13 福州瑞克布朗医药科技有限公司 二硅酸锂玻璃陶瓷及其制备方法和应用
CN113248153B (zh) * 2021-05-26 2022-07-29 福州瑞克布朗医药科技有限公司 二硅酸锂玻璃陶瓷及其制备方法和应用
CN115028364A (zh) * 2022-06-07 2022-09-09 山东国瓷功能材料股份有限公司 玻璃陶瓷、其制备方法及牙齿修复材料
CN115028364B (zh) * 2022-06-07 2024-01-16 山东国瓷功能材料股份有限公司 玻璃陶瓷、其制备方法及牙齿修复材料

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