Ultrathin lithium disilicate and translucent zirconia crowns for posterior teeth: Survival and failure modes

Author(s)

Jalkh, Ernesto B. Benalcazar ; Ramalho, Ilana S. ; Bergamo, Edmara T. P. ; Alves, Larissa M. M. ; Tanaka, Ricardo ; Witek, Lukasz ; Coelho, Paulo G. ; Hirata, Ronaldo ; Bonfante, Estevam A.

• Document type: Journal article
• Source: Journal of Esthetic and Restorative Dentistry; v. N/A, p. 10-pg., 2023-09-07.

Abstract

PurposeTo evaluate the reliability and failure modes of ultrathin (0.5 mm) lithium disilicate, translucent and ultra-translucent zirconia crowns for posterior teeth restorations.Materials and MethodsFifty-four mandibular first molar crowns of three ceramic materials: (1) Lithium disilicate (e.max CAD, Ivoclar Vivadent), (2) 3Y-TZP (Zirconn Translucent, Vipi), and (3) 5Y-PSZ (Cercon XT, Dentsply Sirona), with 0.5 mm of thickness were milled and cemented onto composite resin abutments. Eighteen samples of each group were tested under mouth-motion step-stress accelerated life testing in a humid environment using mild, moderate, and aggressive profiles. Data was subjected to Weibull statistics. Use level curves were plotted and reliability was calculated for a given mission of 100,000 cycles at 100, 200, and 300 N. Fractographic analyses of representative samples were performed in scanning electron microscope.ResultsBeta (& beta;) values suggest that failures were dictated by material's strength for lithium disilicate and by fatigue damage accumulation for both zirconias. No significant differences were detected in Weibull modulus and characteristic strength among groups. At a given mission of 100,000 cycles at 100 N, lithium disilicate presented higher reliability (98% CB: 95-99) regarding 3Y-TZP and 5Y-PSZ groups (84% CB: 65%-93% and 79% CB: 37 &-94%, respectively). At 200 N, lithium disilicate reliability (82% CB: 66%-91%) was higher than 5Y-PSZ (20% CB: 4%-44%) and not significantly different from 3Y-TZP (54% CB: 32%-72%). Furthermore, at 300 N no significant differences in reliability were detected among groups, with a notable reduction in the reliability of all materials. Fractographic analyses showed that crack initiated at the interface between the composite core and the ceramic crowns due to tensile stress generated at the intaglio surface.ConclusionsUltrathin lithium disilicate crowns demonstrated higher reliability relative to zirconia crowns at functional loads. Lithium disilicate and zirconia crown's reliability decreased significantly for missions at higher loads and similar failure modes were observed regardless of crown material. The indication of 0.5 mm thickness crowns in high-load bearing regions must be carefully evaluated.Clinical SignificanceUltraconservative lithium disilicate and zirconia crowns of 0.5 mm thickness may be indicated in anterior restorations and pre-molars. Their clinical indication in high-load requirement regions must be carefully evaluated. (AU)

• 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: 21/08018-2 - Nanomechanical layer characterization of graded ATZ and ZTA composites
• Grantee: Edmara Tatiely Pedroso Bergamo
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• 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: 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: 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: 16/18818-8 - 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
• 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: 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
• 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