Processing and characterization of an experimental bilayer first-generation 3Y-TZP and super-translucent 4Y-PSZ zirconia subjected to hydrothermal aging

Author(s):Show less -

Galli, M. Z. ; Campos, T. M. B. ; Benalcazar-Jalkh, E. B. ; Alves, L. M. M. ; Marun, M. M. ; Sousa, E. O. ; Yamaguchi, S. ; Thim, G. P. ; Gierthmuehlen, P. C. ; Monteiro-Sousa, R. S. ; Witek, L. ; Coelho, P. G. ; Carvalho, L. F. ; Bonfante, E. A.

• Document type: Journal article
• Source: MATERIALS TODAY COMMUNICATIONS; v. 46, p. 12-pg., 2025-06-01.

Abstract

The aim of this study was to develop an experimental bilayer zirconia system composed of first-generation 3YTZP and super-translucent 4Y-PSZ, and to characterize its microstructural, optical, and mechanical properties before and after hydrothermal aging, comparing them with its monolithic controls. Disc specimens were produced through uniaxial pressing of commercial 3Y-SBE and ZPEX 4 powders (Tosoh Corporation) and sintered at 1550 degrees C for 2 hours. Hydrothermal aging was performed in a hydrothermal reactor for 20 hours at 134 degrees C and 2.2 bar. Microstructural characterization by scanning electron microscopy revealed smaller grains in the bilayer group compared to the control groups. X-ray diffraction indicated a lower susceptibility to hydrothermal degradation for the bilayer group, while Raman spectroscopy showed that degradation occurred only in the outermost layer. Optical characterization demonstrated that the bilayer system successfully combined the higher translucency of 4Y with the superior opacity of 3Y, resulting in an effective aesthetic balance between the layers. Mechanical evaluation indicated that the bilayer system remained stable before and after hydrothermal aging, with strength values exceeding 800 MPa. Fractographic analysis revealed that cracks originated on the tensile side and propagated towards the compressive side. It is concluded that the 3Y/4Y bilayer zirconia system presents a promising balance between aesthetics and strength, making it a viable solution for various dental applications. (AU)

• FAPESP's process: 23/08712-1 - Glass infiltrated multilayer zirconia: optical, mechanical and hydrothermic stability characterization
• Grantee: Raphaelle Santos Monteiro de Sousa
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 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
• Grantee: Estevam Augusto Bonfante
• Support Opportunities: Research Grants - Young Investigators Grants - Phase 2
• FAPESP's process: 23/07289-8 - Influence of low temperature degradation on the wear resistance of recycled translucent zirconia
• Grantee: Larissa Marcia Martins Alves
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• FAPESP's process: 20/12874-9 - Infiltration graded by glass in an experimental composite based on whiskers of alumina and zircônia: development, microstructural characterization and optical and mechanical properties
• Grantee: Tiago Moreira Bastos Campos
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 22/07733-2 - Physical and mechanical characterization of a bilayered zirconia system: influence of hydrothermal aging
• Grantee: Edisa de Oliveira Sousa
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 22/05495-7 - Multi-user equipment approved in grant 21/06730-7: ElectroPuls E3000 All-Electric Dynamic Test Instrument, INSTRON
• Grantee: Estevam Augusto Bonfante
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 21/07440-2 - Graduated glass infiltration in an ultra-translucent zirconia (5Y-PSZ): synthesis, processing and characterization of physical and mechanical properties
• Grantee: Larissa Marcia Martins Alves
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 22/05496-3 - Multi-user equipment approved in grant 21/06730-7: Macrodurômetro VH1150 - Buehler
• Grantee: Estevam Augusto Bonfante
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 22/07157-1 - Physical and mechanical characterization of a multilayered system using recycled zirconia
• Grantee: Ernesto Byron Benalcazar Jalkh
• Support Opportunities: Scholarships in Brazil - Post-Doctoral