EFFECT OF HYDROTHERMAL AGING ON THE LIFETIME OF MULTILAYER ZIRCONIA

• Grant number: 24/13770-3
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: January 15, 2025
• End date: January 14, 2026
• Field of knowledge: Health Sciences - Dentistry
• Principal Investigator: Estevam Augusto Bonfante
• Grantee: Raphaelle Santos Monteiro de Sousa
• Supervisor: Jason Alan Griggs
• Host Institution: Faculdade de Odontologia de Bauru (FOB). Universidade de São Paulo (USP). Bauru , SP, Brazil
• Institution abroad: University of Mississippi Medical Center (UMMC), United States
• Associated to the scholarship: 23/08712-1 - Glass infiltrated multilayer zirconia: optical, mechanical and hydrothermic stability characterization, BP.DR

Abstract

The multilayer zirconia system aims to combine the strength of 3Y-TZP with the optimized translucency of 4Y-PSZ and 5Y-PSZ. However, its lifetime in the oral environment is not yet fully understood. To expand and optimize the mechanical and structural analyses of multilayer zirconia before and after hydrothermal aging, this BEPE (Research Internship Abroad) proposal aims to complement ongoing analyses of the PhD FAPESP scholarship #2023/08712-1, linked to the Young Investigator Award phase 2 # 2021/06730-7. The objective is to evaluate the correlation between surface changes, recently detected in our lab through micrographs, (but to be comprehensively characterized in this BEPE proposal) and the lifetime of multilayer zirconia (3Y-TZP+4Y-PSZ+5Y-PSZ) before and after hydrothermal aging. Specimens will be processed by successive uniaxial pressing of discs of 12x1.2 mm (ISO 6872) (n=90) and divided into three groups: immediate and subjected to two forms of aging in a hydrothermal reactor (134ºC at 2.2 bar) submerged for 10h and in steam for 10h. The lifetime will be characterized by accelerated fatigue tests. Surface roughness will be accurately evaluated using specific equipment at the Department of Biomedical Materials Science at the University of Mississippi Medical Center (UMMC) through the 3D surface profiler laser microscope (VK - X3000 series, Keyence). Roughness data will be correlated with lifetime outcomes before and after LTD. All specimens will be characterized for microstructure and crystalline content analyses by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman spectroscopy. Weibull statistical will be used for lifetime analysis.