title: Chairside CAD/CAM materials. Part 1: Measurement of elastic constants and microstructural characterization.
abstract: A deeper understanding of the mechanical behavior of dental restorative materials requires an insight into the materials elastic constants and microstructure. Here we aim to use complementary methodologies to thoroughly characterize chairside CAD/CAM materials and discuss the benefits and limitations of different analytical strategies.
  
  
  
  Eight commercial CAM/CAM materials, ranging from polycrystalline zirconia (e.max ZirCAD, Ivoclar-Vivadent), reinforced glasses (Vitablocs Mark II, VITA; Empress CAD, Ivoclar-Vivadent) and glass-ceramics (e.max CAD, Ivoclar-Vivadent; Suprinity, VITA; Celtra Duo, Dentsply) to hybrid materials (Enamic, VITA; Lava Ultimate, 3M ESPE) have been selected. Elastic constants were evaluated using three methods: Resonant Ultrasound Spectroscopy (RUS), Resonant Beam Technique (RBT) and Ultrasonic Pulse-Echo (PE). The microstructures were characterized using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), Raman Spectroscopy and X-ray Diffraction (XRD).
  
  
  
  Young's modulus (E), Shear modulus (G), Bulk modulus (B) and Poisson's ratio (ν) were obtained for each material. E and ν reached values ranging from 10.9 (Lava Ultimate) to 201.4 (e.max ZirCAD) and 0.173 (Empress CAD) to 0.47 (Lava Ultimate), respectively. RUS showed to be the most complex and reliable method, while the PE method the easiest to perform but most unreliable. All dynamic methods have shown limitations in measuring the elastic constants of materials showing high damping behavior (hybrid materials). SEM images, Raman spectra and XRD patterns were made available for each material, showing to be complementary tools in the characterization of their crystal phases.
  
  
  
  Here different methodologies are compared for the measurement of elastic constants and microstructural characterization of CAD/CAM restorative materials. The elastic properties and crystal phases of eight materials are herein fully characterized.
authors.affiliation: Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Glueckstrasse 11, 91054 Erlangen, Germany.
authors.forename: Renan
authors.initials: R
authors.lastname: Belli
authors.affiliation: Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Glueckstrasse 11, 91054 Erlangen, Germany; Department of Restorative Dentistry, Faculty of Dentistry, University of Concepción, Concepción, Chile.
authors.forename: Michael
authors.initials: M
authors.lastname: Wendler
authors.affiliation: Department of Glass and Ceramics, Institute of Materials Science, Friedrich-Alexander University of Erlangen-Nuremberg, Martenstrasse 5, Erlangen, Germany.
authors.forename: Dominique
authors.initials: D
authors.lastname: de Ligny
authors.affiliation: Department of Glass and Ceramics, Institute of Materials Science, Friedrich-Alexander University of Erlangen-Nuremberg, Martenstrasse 5, Erlangen, Germany.
authors.forename: Maria Rita
authors.initials: MR
authors.lastname: Cicconi
authors.affiliation: Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Glueckstrasse 11, 91054 Erlangen, Germany.
authors.forename: Anselm
authors.initials: A
authors.lastname: Petschelt
authors.affiliation: Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria.
authors.forename: Herwig
authors.initials: H
authors.lastname: Peterlik
authors.affiliation: Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Glueckstrasse 11, 91054 Erlangen, Germany. Electronic address: ulrich.lohbauer@fau.de.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Lohbauer
mesh_terms: D002516:Ceramics; D017076:Computer-Aided Design; D003764:Dental Materials; D003776:Dental Porcelain; D008422:Materials Testing; D014961:X-Ray Diffraction
chemical_list: D003764:Dental Materials; D003776:Dental Porcelain
keywords: CAD/CAM; Ceramic; Chairside; Elastic modulus; Microstructure; Poisson’s ratio; Resin composite