The effect of thickness and sintering mode on the impact strength of a multi-layered zirconia

• Grant number: 23/01337-0
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Start date: September 18, 2023
• End date: February 28, 2024
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Renata Marques de Melo Marinho
• Grantee: Beatriz Serralheiro da Cruz
• Supervisor: Cornelis Johannes Kleverlaan
• Host Institution: Instituto de Ciência e Tecnologia (ICT). Universidade Estadual Paulista (UNESP). Campus de São José dos Campos. São José dos Campos , SP, Brazil
• Institution abroad: Academic Centre for Dentistry Amsterdam (ACTA), Netherlands
• Associated to the scholarship: 22/10077-0 - ENERGY FOR INTERFACIAL FRACTURE OF A MULTI-LAYERED ZIRCONIA IN MIXED TEST MODE, BP.MS

Abstract

Dental ceramics and specially zirconia is one of the top choices nowadays as restorative materials in prosthetic rehabilitations. After so many advances in material sciences, zirconias are no longer just a white and opaque material, but now translucent and even polychromatic and multi-layered, with multiple clinical indications. Multilayered models can be found with both translucency gradation and homogeneous strength, as well as translucency and strength gradation. Particularly for those with strength gradation, positioning of the restoration in the disc to be milled and the sintering protocol are factors that can affect the performance of the material in the long term, and it is these factors that must be taken into consideration in the milling process of multilayer zirconia. Nevertheless, the literature does not yet have conclusive answers on how fast sintering can affect the mechanical properties of strength gradient multilayered zirconia. It is also important to understand how this material behaves in situations of higher or more abrupt loading, in addition to the behavior under normal conditions in the long term. The present study will aim to determine the impact strength of different zones of the same multilayer zirconia with strength gradation, at different thicknesses and under different sintering modes. 180 zirconia bars will be subjected to impact strength testing. The groups will be divided according to the sintering protocol, the thickness of the specimens and the position of the specimen in relation to the disk (3Y-TZP, Transition Zone or 5Y-TZP). Complementary analyses will be done by X-ray diffraction (XRD), fractographic analysis and Weibull analysis. (AU)