FATIGUE RESISTANCE OF A GLASS INFILTRATED TRANSLUCENT ZIRCONIA (4Y-PSZ) FOR DENTAL APPLICATIONS

• Grant number: 23/02844-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date until: May 01, 2023
• End date until: April 30, 2025
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Ernesto Byron Benalcazar Jalkh
• Grantee: Felipe Machado de Souza
• Host Institution: Faculdade de Odontologia de Bauru (FOB). Universidade de São Paulo (USP). Bauru , SP, Brazil
• Associated research grant: 21/06730-7 - Towards sustainable zirconia recycled from milling waste and boosted by glass infiltration for restorative use, and of the development of strong, graded, and aging resistant multilayered zirconia blocks, AP.JP2

Abstract

Among the different generations of dental zirconia that are commercially available, ultra-translucent zirconia has generated interest in the scientific community due to its high translucency and resistance to low-temperature degradation (LTD). These characteristics are related to the high cubic phase content which is obtained by increasing the amount of stabilizers (>4mol% Y2O3). However, the increased cubic phase restricts the phase transformation toughening, having a detrimental effect on the mechanical performance of the material, and limiting its spectrum of clinical indication. Previous works carried out by the present group within the scope of the Young Investigator Grants 1 # 2012/19078-7 and 2 # 2021/06730-7, have demonstrated a significant improvement in the mechanical properties of glass-infiltrated polycrystalline composites. Preliminary data on gradient structures suggest increments in resistance of up to 300 MPa for infiltrated materials compared to control groups (FAPESP 2019/08693-1). This project, supervised by a postdoctoral fellow linked to FAPESP the Young Investigator-2021/06730-7 grant, proposes the manufacture of graded structures through glass infiltration of third-generation ultra-translucent zirconia (4Y-PSZ), aiming at improving its mechanical performance under fatigue. Specimens of 4Y-PSZ infiltrated with glass will be prepared following the previously established methodology and their mechanical properties will be evaluated by step stress accelerated life testing that will be carried out in a humid environment until failure or suspension following the load profiles described in the FAPESP scholarship 2018/03072-6. The distribution of failures will be used to determine the Weibull probability curves and the probability of survival at given missions for relevant loads and number of cycles. Failure mode and fractographic analyses will be performed through stereo and scanning electron microscopy.