Aging resistant ZTA composite for dental applications: Microstructural, optical and mechanical characterization

Author(s):Show less -

Jalkh, Ernesto Byron Benalcazar ^{[1, 2]} ; Monteiro, Kelli Nunes ^[3] ; Cesar, Paulo Francisco ^[3] ; Genova, Luis Antonio ^[4] ; Bergamo, Edmara T. P. ^[2] ; Lopes, Adolfo Coelho de Oliveira ^[2] ; Lima, Erick ^[3] ; Lisboa-Filho, Paulo Noronha ^[5] ; Campos, Tiago Moreira Bastos ^[6] ; Witek, Lukasz ^{[1, 7]} ; Coelho, Paulo G. ^{[1, 8, 9]} ; Borges, Ana Flavia Sanches ^[10] ; Bonfante, Estevam A. ^[2]

Affiliation

^[1] NYU, Coll Dent, Dept Biomat & Biomimet, New York, NY - USA

^[2] Univ Sao Paulo, Bauru Sch Dent, Dept Prosthodont & Periodontol, Al Otavio Pinheiro Brisola 9-75, Bauru, SP - Brazil

^[3] Univ Sao Paulo, Sch Dent, Dept Biomat & Oral Biol, Sao Paulo, SP - Brazil

^[4] Inst Res Nucl Energy, Sao Paulo, SP - Brazil

^[5] Sao Paulo State Univ, Dept Phys, Bauru, SP - Brazil

^[6] Technol Inst Aeronut, Sao Jose Dos Campos, SP - Brazil

^[7] NYU, Tandon Sch Engn, Dept Biomed Engn, Brooklyn, NY - USA

^[8] NYU Tandon Sch Engn, Mech & Aerosp Engn, New York, NY - USA

^[9] NYU Langone Med Ctr, Hansjorg Wyss Dept Plast Surg, New York, NY - USA

^[10] Univ Sao Paulo, Bauru Sch Dent, Dept Operat Dent Endodont & Dent Mat, Bauru, SP - Brazil

• Document type: Journal article
• Source: Dental Materials; v. 36, n. 9, p. 1190-1200, SEP 2020.
• Web of Science Citations: 0

Abstract

Objective. To synthesize a zirconia toughened alumina (ZTA) composite with 70% alumina reinforced by 30% zirconia for dental applications and to characterize its microstructure and optical properties for comparison with the isolated counterpart materials and a first-generation 3Y-TZP. Methods. Disc-shaped specimens were divided in four groups (n = 70/material): (1) 3YSB-E (first generation 3Y-TZP), (2) Zpex (second generation 3Y-TZP), (3) alumina, and (4) ZTA-Zpex 70/30. After synthesis, ceramic powders were pressed, and green-body samples sintered following a predetermined protocol. Specimens were polished to obtain a mirror surface finish. Apparent density was measured by Archimedes principle. X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to characterize the crystalline content and microstructure. Reflectance tests were performed to determine the contrast-ratio (CR) and translucency-parameter (TP). Mechanical properties were assessed by biaxial flexural strength (BFS) test. All analyses were conducted before and after artificial aging (20 h, 134 degrees C 2.2 bar). Optical parameters were evaluated through repeated-measures analysis of variance and Tukey tests (p < 0.05). BFS data were analyzed using Weibull statistics (95% CI). Results. High density values (95-99%) were found for all ceramic materials and SEM images exhibited a dense microstructure. While XRD patterns revealed the preservation of crystalline content in the ZTA composite, an increase in the monoclinic peak was observed for pure zirconias after aging. Significantly higher CR and lower TP values were observed for the ZTA composite, followed by alumina, 3YSB-E, and Zpex. The highest characteristic stress was recorded for 3YSB-E, followed by intermediate values between ZTA and Zpex, and the lowest for alumina. Aging affected the optical and mechanical properties of both zirconias, while remained stable for ZTA composite and alumina. Significance. The synthesis of experimental 70-30% ZTA composite was successful and its relevance for dental applications relies on its higher masking ability, aging resistance, and strength similar to zirconia. (C) 2020 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved. (AU)

• FAPESP's process: 19/08693-1 - Experimental glass-infiltrated alumina-zirconia composites: characterization of microstructure, optical and mechanical properties.
• Grantee: Edmara Tatiely Pedroso Bergamo
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 19/00452-5 - EXPERIMENTAL 70%Al2O3-30%ZrO2 ZTA COMPOSITES: MECHANICAL, ESTRUCTURAL AND TOPHOGRAPHICAL CHARACTERIZATION
• Grantee: Ernesto Byron Benalcazar Jalkh
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• FAPESP's process: 17/19362-0 - DEVELOPMENT, MECHANICAL AND OPTICAL CHARACTERIZATION OF 80% AL2O3 AND 20% ZRO2 ZTA COMPOSITES FOR CAD/CAM PROSTHESES
• Grantee: Adolfo Coelho de Oliveira Lopes
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• FAPESP's process: 18/03072-6 - Experimental 70% Al2O3-30% ZrO2 composites: structural characterization and survival probability before and after aging
• Grantee: Ernesto Byron Benalcazar Jalkh
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 12/19078-7 - Development and processing of Al2O3-ZrO2 translucent composite for CAD/CAM monolithic prostheses: the effect of aging on biaxial flexural strength
• Grantee: Estevam Augusto Bonfante
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 16/17793-1 - Development and mechanical and optical characterization of 80% Al2O3 and 20% ZrO2 translucent composites for CAD/CAM monolithic prostheses
• Grantee: Adolfo Coelho de Oliveira Lopes
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 16/18818-8 - Multi-User Equipment approved in grant 2012/19078-7: ElectroPuls E3000 Linear-Torsion All-Electric dynamic test instrument package
• Grantee: Estevam Augusto Bonfante
• Support Opportunities: Multi-user Equipment Program