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Fatigue performance of distinct CAD/CAM dental ceramics.

Authors :: Lf G
P S
A W
de Jager N
Gkr P
Cj K
Mp R
Lf V
Source :: Journal of the mechanical behavior of biomedical materials [J Mech Behav Biomed Mater] 2020 Mar; Vol. 103, pp. 103540. Date of Electronic Publication: 2019 Nov 15.
Publication Year :: 2020
Abstract: This study investigated the effect of surface roughness (polished vs. CAD/CAM milling roughness simulation) on the fatigue behavior of five dental ceramics for manufacturing CAD/CAM monolithic restorations. Specimens of five dental ceramics (FC- feldspathic; PICN- polymer-infiltrated ceramic-network; ZLS- zirconia-reinforced lithium silicate glass-ceramic; LD-lithium disilicate glass-ceramic; YZ-yttria-stabilized tetragonal zirconia polycrystal), to be tested under fatigue (12 × 12 × 1.2 mm <superscript>3</superscript> ), were assigned into two groups according to surface treatment: polished 'p' (#2500-grit SiC papers) and CAD/CAM milling roughness simulation 'gr' (grinding with #60-grit SiC paper). The fatigue test was performed through the stepwise method (40N-660N; step of 20N; 10,000 cycles/step; 20 Hz frequency). Roughness, topographic and fractographic analyses were performed. The fatigue data were analyzed by Kaplan-Meier and Mantel-Cox (Log rank), and Pearson correlation was used to correlate roughness vs. fatigue data. CAD/CAM milling roughness simulation led to significantly (p < 0.05) greater roughness (Ra and Rz), promoting a more irregular topography with scratches and grooves, and led to a lower fatigue performance for all the tested ceramics. Fractographic analysis depicted the origin of failure at the higher stress concentration side, the side subjected to tensile tension during the fatigue test. The CAD/CAM milling roughness simulation significantly decreased the fatigue performance of the evaluated ceramic materials.<br />Competing Interests: Declaration of competing interest None.<br /> (Copyright © 2019 Elsevier Ltd. All rights reserved.)