Lifetime prediction of veneered versus monolithic lithium disilicate crowns loaded on marginal ridges.

Autor: de Paula VG; Department of Prosthodontics and Periodontology, University of São Paulo, Bauru School of Dentistry, Bauru, SP, Brazil., Bonfante G; Department of Prosthodontics and Periodontology, University of São Paulo, Bauru School of Dentistry, Bauru, SP, Brazil., Lorenzoni FC; Department of Prosthodontics, Unigran University School of Dentistry, Dourados, MS, Brazil., Coelho PG; Department of Biomaterials and Biomimetics, New York University, New York, NY, USA; Hansjörg Wyss Department of Plastic Surgery, NYU Langone Medical Center, New York, NY, USA; Mechanical and Aerospace Engineering, NYU Tandon School of Engineering, New York, NY, USA., Bonjardim LR; Department of Biological Sciences, University of São Paulo, Bauru School of Dentistry, Bauru, SP, Brazil., Fardin VP; Department of Prosthodontics, Universidade Vila Velha, Vila Velha, ES, Brazil., Bonfante EA; Department of Prosthodontics and Periodontology, University of São Paulo, Bauru School of Dentistry, Bauru, SP, Brazil. Electronic address: estevam.bonfante@fob.usp.br.
Jazyk: angličtina
Zdroj: Dental materials : official publication of the Academy of Dental Materials [Dent Mater] 2019 Mar; Vol. 35 (3), pp. 511-522. Date of Electronic Publication: 2019 Jan 25.
DOI: 10.1016/j.dental.2019.01.007
Abstrakt: Objective: To evaluate the probability of survival of monolithic and porcelain veneered lithium disilicate crowns comprised by a conventional or modified core when loaded on marginal ridges.
Methods: Lithium disilicate molar crowns (n=30) were fabricated to be tested at mesial and distal marginal ridges and were divided as follows: (1) bilayered crowns with even-thickness 0.5mm framework (Bi-EV); (2) bilayered crowns with modified core design (Bi-M-lingual collar connected to proximal struts), and: (3) monolithic crowns (MON). After adhesively cemented onto composite-resin prepared replicas, mesial and distal marginal ridges of each crown (n=20) were individually cyclic loaded in water (30-300N) with a ceramic indenter at 2Hz until fracture. The 2-parameter Weibull was used to calculate the probability of survival (reliability) (90% 2-sided confidence bounds) at 1, 2, and 3 million cycles and mean life.
Results: The reliability at 1 and 2 million cycles was significantly higher for MON (47% and 19%) compared to Bi-EV (20% and 4%) and Bi-M (17% and 2%). No statistical difference was found between bilayered groups. Only the MON group presented crown survival (7%) at 3 million cycles. The mean life was highest for MON (1.73E+06), lowest for Bi-M (573,384) and intermediate for Bi-E (619,774). Fractographic analysis showed that the fracture originated at the occlusal surface. The highest reliability was found for MON crowns. The modified framework design did not improve the fatigue life of crowns.
Significance: Monolithic lithium disilicate crowns presented higher probability of survival and mean life than bilayered crowns with modified framework design when loaded at marginal ridges.
(Copyright © 2019 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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