IPS e.max Press EnglishRM - ROE Dental Laboratory

1 IPS Press Scientific Documentation Scientific Documentation IPS Press Page 2 of 24 Table of contents 1. Overview of IPS range of IPS 2. Technical 3. Material science Physical Flexural Fracture 4. In vitro Fracture strength of anterior Fracture strength of three-unit posterior Light Marginal Fracture strength of partial 5. External clinical University of University of University of Florida (Gainesville)..17 University of King s College, University of 6. Chemical In vitro Sensitization, 7. Scientific Documentation IPS Press Page 3 of 24 1.

2 Introduction Overview of IPS range of products IPS is an all-ceramic system that consists of the following five components: IPS Press (lithium disilicate glass-ceramic ingot for the Press technique) IPS ZirPress (fluorapatite glass-ceramic ingot for the Press -on technique) IPS CAD (lithium disilicate glass-ceramic block for the CAD/CAM technique) IPS ZirCAD (zirconium oxide block for the CAD/CAM technique) IPS Ceram (fluorapatite veneering ceramic) Scientific Documentation IPS Press Page 4 of 24 IPS Press Material/ Manufacture Fig. 1: IPS Press ingots IPS Press is a lithium disilicate glass-ceramic ingot for use with the Press technique (Fig.)

3 1). The ingots are available in two degrees of opacity. These ingots have been developed on the basis of a lithium silicate glass ceramic ( ). The ingots are produced by bulk casting. A continuous manufacturing process based on glass technology (casting/pressing procedure) is utilized in the manufacture of the ingots. This new technology uses optimized processing parameters, which prevent the formation of defects (pores, pigments, etc) in the bulk of the ingot. Fig. 2: SiO2-Li2O system 1 (Schmelze = melt) As lithium disilicate glass ceramic and zirconium oxide (IPS ZirCAD) feature a similar coefficient of thermal expansion, the same layering ceramic (IPS Ceram) can be used in conjunction with both of these materials.

4 IPS Press is processed in the Dental Laboratory with the known Empress pressing equipment. This equipment is distinguished for providing a high accuracy of fit. Scientific Documentation IPS Press Page 5 of 24 Coloration The new manufacturing method does not allow color pigments to be added to the material, as these pigments would melt out when the melting temperature is reached. Instead, polyvalent ions, which are dissolved in the glass, are utilized to provide the desired color. The combination, concentration and valence of the coloration ions play an essential role in this mechanism. The advantage of using an ion-based coloration mechanism is that the color-releasing ions can be homogeneously distributed in the single-phase material.

5 By contrast, color pigments represent imperfections in the microstructure. Microstructure The microstructure of IPS Press consists of lithium disilicate crystals (approx. 70%), Li2Si2O5, which are embedded in a glassy matrix. Lithium disilicate, the main crystal phase, consists of needle-like crystals (Fig. 3). The crystals measure 3 to 6 m in length. Fig. 3: Microstructure of IPS Press (SEM, etched with HF vapor for 30 s) Scientific Documentation IPS Press Page 6 of 24 2. Technical data IPS Press Ingots for the ceramic Press technique Standard composition: (in wt %) SiO2 Li2O K2O P2O5 ZrO2 ZnO + other oxides + coloring oxides Physical properties: In compliance with: ISO 6872 Dental ceramic ISO 9693 Metal-ceramic Dental restorative systems Flexural strength (biaxial) 400 40 MPa Chemical solubility 40 10 g/cm2 Coefficient of thermal expansion (100 - 400 C) 10-6K-1 Coefficient of thermal expansion (100 - 500 C) 10-6K-1 Scientific Documentation IPS Press Page 7 of 24 3.

6 Material science investigations Physical properties Physical property Value Investigator Fracture toughness (SEVNB) MPam in-house, (Ivoclar Vivadent AG, Schaan) Modulus of elasticity 95 5 GPa in-house (Ivoclar Vivadent AG, Schaan) Modulus of elasticity GPa Albakry et Modulus of elasticity GPa Lohbauer8 Modulus of elasticity GPa Anusavice2 Poisson s ratio, Albakry et Vickers hardness 5800 100 MPa in-house (Ivoclar Vivadent AG, Schaan) Hardness GPa Albakry et Density g/cm3 in-house (Ivoclar Vivadent AG, Schaan) Table 1: Physical properties Flexural strength Flexural strength of IPS Press (various methods) Flexural strength values largely depend on the methods used to measure them.

7 Fig. 4 provides an overview of the flexural strength values measured for a single material using different measuring methods. 0100200300400500600 Guazzato et al.; b)Albakry et al.; a)Marx et al.; c)Marx, Fischer; b)Lohbauer; c)Ludwig et al.; b)Anusavice; d)Kappert; a)Sorensen et al.; a)Sorensen et al.; e)Berge et al.; f)Examiner; Method (see Table)Flexural strength [MPa] Fig. 4: Flexural strength values measured for IPS Press using different methods (see also Table 2) Scientific Documentation IPS Press Page 8 of 24 Examiner Flexural strength [MPa] Measuring method: Berge et ; f) Biaxial flexural strength, ISO 6872; test in H2O Sorensen et ; e) Biaxial flexural strength (wet test) Sorensen et ; a) Biaxial flexural strength Kappert5; a) 426 Biaxial flexural strength Anusavice6; d) 239 4-point flexural strength after 48 hours of storage in H2O Ludwig et ; b) 426 3-point flexural strength Lohbauer8; c) Weibull strength ; 4-point flexural strength, DIN EN 843-1 Marx, Fischer9.

8 B) 466 3-point flexural strength Marx et ; c) 388 Weibull strength ; 4-point flexural strength, DIN EN 843-1 Albakry et ; a) 440 Biaxial flexural strength Guazzato et ; b) 303 3-point flexural strength Table 2: Values and measuring methods shown in Fig. 4 Biaxial flexural strength of different pressable ceramics Albakry et determined the biaxial flexural strength and Weibull modulus of different pressable ceramic materials of Ivoclar Vivadent AG. Twenty discs were tested for each material; the tests were carried out in compliance with ASTM F 394-78. 0100200300400500 IPS EmpressIPS Empress2 IPS PressBiaxial flexural strength [MPa]0246810 Weibull modulusBiaxial flexural strength [MPa]Weibull modulus Fig.

9 5: Biaxial flexural strength and Weibull modulus of selected pressable ceramics (Albakry et ) The strength values of IPS Press and IPS Empress2, which are higher than IPS Empress, are attributable to the composition of these materials (lithium disilicate crystals). IPS Press and IPS Empress2 show a higher Weibull modulus than IPS Empress. This means that the values measured for these materials are more reliable and have less variance. Weibull strength Strength measurements in ceramic materials tend to yield results with a wide distribution. Consequently, what is known as the Weibull strength is often mentioned in conjunction with ceramic materials.

10 The Weibull strength indicates the load at which of all samples measured in a single series of measurements fail. Other terms used for Weibull strength are characteristic strength or mean strength . Scientific Documentation IPS Press Page 9 of 24 Marx et ,10 determined the Weibull strength by means of a 4-point flexural strength test (DIN V ENV 843-1), using a sample size of n=30. 050100150200250300350400450 IPS EmpressIPS Empress2 IPS PressWeibull strength [MPa] Fig. 6: Weibull strength of selected pressable ceramic materials (Marx et ,10) The Weibull strength of IPS Press is higher than that of IPS Empress 2. Fracture toughness The fracture toughness KIC provides a measure of the material s resistance to crack propagation.