Effect of hydrothermic degradation on wear resistance, surface topography, microhardness, and toughness of 3Y/5Y-TZP and multilayer zirconia

• Grant number: 21/11320-2
• Support Opportunities: Scholarships in Brazil - Master
• Start date: July 01, 2022
• End date: November 30, 2023
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Marco Antonio Bottino
• Grantee: Karina Barbosa Souza
• Host Institution: Instituto de Ciência e Tecnologia (ICT). Universidade Estadual Paulista (UNESP). Campus de São José dos Campos. São José dos Campos , SP, Brazil

Abstract

This study proposes to evaluate the effect of degradation on the wear pattern, surface topography, microhardness and toughness of 3Y-TZP, 5Y-TZP and multilayer zirconia. For this, 3Y-TZP - Zpex and 5Y-TZP - Zpex Smile (Tosoh Corporation, Japan) and ZirCAD Prime (Ivoclar Vivadent, Liechtenstein) zirconia will be used for making discs (Ø= 12 mm and 1.2 mm thick). The discs will be divided into 6 groups (n=23) between the factors "zirconia type" (3Y-TZP, 5Y-TZP and multilayer zirconia) and "hydrothermal degradation" (with hydrothermal degradation and without hydrothermal degradation). Except for the control groups, the samples will undergo hydrothermal degradation in a hydrothermal reactor (134 æC, 20 hours, 2.2 bar). The samples will be subjected to wear by horizontal sliding of 2 mm (n=12) in distilled water, using as antagonist a spherical end (Ø= 2mm) in 3Y-TZP zirconia (30N load, 1.7 Hz, 300,000 cycles). The wear volume of the discs will be quantified in a contact profilometer. The antagonist sphere volume will be determined before and after wear by the sphere cap volume formula and the qualitative analysis will be performed by an optical stereomicroscope. Chemical analysis of x-ray diffraction (n=1), Vickers microhardness (n=5) and fracture toughness (n=5) will be performed for all groups. Scanning electron microscopy (50X and 200X) will be performed on the surface of samples from all groups. The wear volume, microhardness and fracture toughness data will be statistically analyzed using ANOVA 2 factors and Tukey 5%. Data from X-ray diffraction and scanning electron microscopy analyzes will be submitted to descriptive analysis. (AU)