Lifetime prediction of zirconia and metal ceramic crowns loaded on marginal ridges

Author(s)

Fardin, Vinicius P. ; de Paula, Vitor Guarconi ; Bonfante, Estevam A. ; Coelho, Paulo G. ; Bonfante, Gerson

• Document type: Journal article
• Source: Dental Materials; v. 32, n. 12, p. 1543-1554, DEC 2016.
• Web of Science Citations: 5

Abstract

Objective. To evaluate the fatigue life of zirconia-veneered and metal-ceramic crowns comprised by an even thickness or a modified framework design when loaded on marginal ridges. Methods. Eighty marginal ridges were present after fabrication of forty molar crowns cemented onto composite-resin replicas and divided (n = 20/each), in the following groups: metal-ceramic with even thickness (MCev) or with a modified framework design (MCm, lingual collar with proximal struts); porcelain-fused to zirconia with even thickness (PFZev) or with the modified framework design (PFZm). Each marginal ridge (mesial and distal) was subjected to cyclic loading separately with a lithium disilicate indenter for 10(6) cycles or until fracture. Kruskal-Wallis and Wilcoxon matched pair test (p < 0.05) evaluated both marginal ridges. Every 125,000 cycles, the test was interrupted for damage inspection. Weibull distribution (90% confidence bounds) determined the probability of survival (reliability). Results. Weibull 2-parameter contour-plot showed significantly higher fatigue life for PFZev compared to MC, and comparable with PFZm. A significant decrease in reliability was observed between groups from 625,000 until 10(6) cycles. Metal-ceramic groups presented significantly lower probability of survival at 10(6) cycles (MCev = 0.66% and MCm = 4.73%) compared to PFZm (23.41%) and PFZev (36.68%). Fractographic marks showed a consistent fracture origin and direction of crack propagation. Reliability was higher for porcelain-fused to zirconia than for metal ceramic crowns, regardless of framework design. Significance. Zirconia-veneered crowns presented decreased fracture rates compared to metal ceramics, even when loaded at marginal ridges, regardless of framework design. (C) 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved. (AU)

• 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 type: Research Grants - Young Investigators Grants
• FAPESP's process: 11/23177-8 - Evaluation of reliability and failure modes of ceramic crown systems depending on framework design and location of load application
• Grantee: Gerson Bonfante
• Support type: Regular Research Grants
• FAPESP's process: 13/20806-0 - Evaluation of damage and failure modes of fixed partial denture of totally ceramic depending on marginal ridge load application
• Grantee: Vinicius Pavesi Fardin
• Support type: Scholarships in Brazil - Doctorate
• FAPESP's process: 11/16377-0 - Evaluation of reliability and failure modes of ceramic crown systems depending on framework design and location of load application
• Grantee: Vinicius Pavesi Fardin
• Support type: Scholarships in Brazil - Master
• FAPESP's process: 14/22859-6 - Effect of framework design of fatigued zirconia 3-unit prostheses on the nanomechanical properties
• Grantee: Vinicius Pavesi Fardin
• Support type: Scholarships abroad - Research Internship - Doctorate