Microstructural characterization and mechanical behavior of glassceramics crystallized by microwave energy

• Grant number: 19/06458-5
• Support type: Scholarships abroad - Research Internship - Master's degree
• Effective date (Start): August 02, 2019
• Effective date (End): October 29, 2019
• Field of knowledge: Health Sciences - Dentistry
• Principal Investigator: Guilherme de Siqueira Ferreira Anzaloni Saavedra
• Grantee: Ana Beatriz Gomes de Carvalho
• Supervisor abroad: Cornelis Johannes Kleverlaan
• Home Institution: Instituto de Ciência e Tecnologia (ICT). Universidade Estadual Paulista (UNESP). Campus de São José dos Campos. São José dos Campos , SP, Brazil
• Local de pesquisa : Academic Centre for Dentistry Amsterdam (ACTA), Netherlands
• Associated to the scholarship: 18/09577-2 - Microstructural characterization and mechanical behavior of glass-ceramics crystallized by microwave energy, BP.MS

Abstract

The aim of this study will be to verify the viability of an alternative processof crystallization using microwave energy and to establish a crystallizationprotocol for three commercial glass-ceramics; to evaluate the effect of thiscrystallization on microstructure, density, hardness, fracture toughnessand biaxial flexural strength of these glass-ceramics; and to analyze theiroptical properties (translucency). The null hypothesis is that thecrystallization by microwave energy will not affect the microstructuralcharacteristics and consequently the mechanical properties of theseceramic materials. 180 discs will be made from blocks of three differentglass-ceramics: lithium disilicate (IPS e.max CAD, Ivoclar Vivadent) andlithium silicates reinforced by zirconia (I - Suprinity, Vita Zahnfabrik; II -Celtra, Dentsply); according to ISO 6872 (dimensions: 12 x 1.2 mm). SiCpapers with granulation #400, 600, 1200 and 2500 will be used forspecimens polishing. Half specimens of each group will be crystallized inthe conventional furnace, according to the manufacturer'srecommendations, and the other half specimens will be crystallized bymicrowave energy using a protocol that will be defined by a previous pilotstudy. The microstructural characterization will be made from themeasurement of density, translucency, scanning electron microscopy(SEM) and X-ray diffraction (XRD). The mechanical behavior will bemeasured by the biaxial flexural test, Vickers hardness and fracturetoughness. Fracture analysis will also be performed on the fracturedspecimens to determine the origin of the fracture and the relationshipbetween the crack and the microstructure of the studied materials