Bergamo, Edmara T. P.
Ramalho, Ilana S.
Lopes, Adolfo C. O.
Gomes, Rafael S.
Bonfante, Esteuam A.
Coelho, Paulo G.
[4, 6, 7]
Del Bel Cury, Altair A.
 Univ Sao Paulo, Dept Prosthodont & Periodontol, Bauru Sch Dent, Bauru, SP - Brazil
 NYU, Coll Dent, Dept Biomat & Biomimet, New York, NY - USA
 Positivo Univ, Grad Program Dent, Curitiba, Parana - Brazil
 NYU Langone Hlth, Sch Med, Hansjorg Wyss Dept Plast Surg, New York, NY - USA
 NYU, Mech & Aerosp Engn, Tandon Sch Engn, New York, NY - USA
Número total de Afiliações: 7
Tipo de documento:
Citações Web of Science:
Objective. To evaluate the reliability and failure mode of zirconia-reinforced lithium silicate (ZLS) molar crowns of different thicknesses. Methods. Monolithic ZLS molar crowns (0.5 mm, 1.0 mm, and 1.5 mm thickness) were modeled and milled using a CAD/CAM system (n = 21/group). Crowns were cemented on dentin-like epoxy resin replicas with a resin cement. The specimens were subjected to single load-to-failure test for step-stress profiles designing. Mouth-motion step-stress accelerated-life test was performed under water by sliding an indenter 0.7 mm lingually down on the distobuccal cusp until specimen fracture or suspension. Use level probability Weibull curves and reliability were calculated and plotted. Polarized-light optical microscope and scanning electron microscope (SEM) were used to characterize fracture patterns. Results. Irrespective of crown thickness, beta (beta) values were higher than 1 and fatigue accelerated failures. While 0.5 mm ZLS crowns exhibited a significant reduction in the probability of survival at 200 N, 300 N and 400 N mission loads (69%, 41% and 19%, respectively), no significant difference was observed between 1.0 mm and 1.5 mm crowns. Both thicknesses have maintained the survivability at approximately 90%. Failure primarily comprised bulk fracture where radial cracks originated from the cementation surface beneath the indenter loading trail and propagated towards the cervical margin. Significance. 1.5 mm- and 1.0 mm-thickness monolithic ZLS crowns presented higher probability of survival compared to 0.5 mm crowns. Bulk fracture was the chief failure mode, regardless of thickness. (C) 2019 Published by Elsevier Inc. on behalf of The Academy of Dental Materials. (AU)