High load frequency at 20Hz: Its effects on the fatigue behavior of a leucite-reinforced glass-ceramic.

High load frequency at 20Hz: Its effects on the fatigue behavior of a leucite-reinforced glass-ceramic. J Mech Behav Biomed Mater. 2020 Jul;107:103769 Authors: Fraga S, Rodrigues CDS, Zucuni CP, Pereira GKR, Barbosa MN, Valandro LF, May LG Abstract Considering the long time spent in low frequency cyclic fatigue tests, this study aimed to evaluate the influence of loading frequency (2 Hz and 20 Hz) on the flexural fatigue strength (FFS) and on the time and number of cycles to failure of a leucite-reinforced glass-ceramic. Disc-shaped specimens were produced using leucite-reinforced glass-ceramic CAD/CAM blocks (IPS Empress CAD), according to ISO 6872/2015. Two fatigue tests were performed. The FFS (n = 17) was determined by staircase approach at a lifetime of 500,000 cycles, for 2 Hz (control - chewing frequency estimative) and 20 Hz (accelerated approach). To determine the time and the number of cycles to failure in flexural fatigue, discs (n = 20) were submitted to a cyclic loading ranging from 10 MPa to 99 MPa (60% of the monotonic strength), until a maximum of 500,000 cycles. Means, standard deviation and confidence intervals (CI) at 95% for FFS were calculated, whereas statistical differences were detected based on maximum likelihood estimations and overlapping of 95% CIs. Kaplan Meier (α = 0.05) and log rank post-hoc tests were used to analyze the time (in minutes) and the number of cycles to failure in the lifetime...
Source: Journal of the Mechanical Behavior of Biomedical Materials - Category: Materials Science Authors: Tags: J Mech Behav Biomed Mater Source Type: research