Abstract
Statement of problem: Investigating the mechanical behavior of ceramics in a clinically simulated scenario contributes to the development of new and tougher materials, improving the clinical performance of restorations. The optimal in vitro environment for testing is unclear.
Purpose: The purpose of this in vitro study was to investigate the failure behavior of a leucite-reinforced glass-ceramic under compression loading and fatigue in different simulated oral environment conditions.
Material and methods: Fifty-three plate-shaped ceramic specimens were produced from computer-aided design and computer-aided manufactured (CAD-CAM) blocks and adhesively cemented onto a dentin analog substrate. For the monotonic test (n=23), a gradual compressive load (0.5 mm/min) was applied to the center of the specimens, immersed in 37ºC water, using a universal testing machine. The initial crack was detected with an acoustic system. The fatigue test was performed in a mechanical cycling machine (37ºC water, 2 Hz) using the boundary technique (n=30). Two lifetimes were evaluated (1×106 and 2×106 cycles). Failure analysis was performed using transillumination. Weibull distribution was used to evaluate compressive load data. A cumulative damage model with an inverse power law (IPL) lifetime-stress relationship was used to fit the fatigue data.
Results: A characteristic failure load of 1615 N and a Weibull modulus of 5 were obtained with the monotonic test. The estimated probability of failure (Pf) for 1×106 cycles at 100 N was 31%, at 150 N it was 55%, and at 200 N it was 75%. For 2×106 cycles, the Pf increased approximately 20% in comparison with the values predicted for 1×106 cycles, which was not significant. The most frequent failure mode was a radial crack from the intaglio surface. For fatigue, combined failure modes were also found (radial crack combined with cone crack or chipping).
Conclusions: Fatigue affects the fracture load and failure mode of leucite-reinforced glass-ceramic.
Purpose: The purpose of this in vitro study was to investigate the failure behavior of a leucite-reinforced glass-ceramic under compression loading and fatigue in different simulated oral environment conditions.
Material and methods: Fifty-three plate-shaped ceramic specimens were produced from computer-aided design and computer-aided manufactured (CAD-CAM) blocks and adhesively cemented onto a dentin analog substrate. For the monotonic test (n=23), a gradual compressive load (0.5 mm/min) was applied to the center of the specimens, immersed in 37ºC water, using a universal testing machine. The initial crack was detected with an acoustic system. The fatigue test was performed in a mechanical cycling machine (37ºC water, 2 Hz) using the boundary technique (n=30). Two lifetimes were evaluated (1×106 and 2×106 cycles). Failure analysis was performed using transillumination. Weibull distribution was used to evaluate compressive load data. A cumulative damage model with an inverse power law (IPL) lifetime-stress relationship was used to fit the fatigue data.
Results: A characteristic failure load of 1615 N and a Weibull modulus of 5 were obtained with the monotonic test. The estimated probability of failure (Pf) for 1×106 cycles at 100 N was 31%, at 150 N it was 55%, and at 200 N it was 75%. For 2×106 cycles, the Pf increased approximately 20% in comparison with the values predicted for 1×106 cycles, which was not significant. The most frequent failure mode was a radial crack from the intaglio surface. For fatigue, combined failure modes were also found (radial crack combined with cone crack or chipping).
Conclusions: Fatigue affects the fracture load and failure mode of leucite-reinforced glass-ceramic.
| Original language | English |
|---|---|
| Pages (from-to) | 812-818 |
| Number of pages | 7 |
| Journal | Journal of Prosthetic Dentistry |
| Volume | 119 |
| Issue number | 5 |
| Early online date | 16 Sept 2017 |
| DOIs | |
| Publication status | Published - May 2018 |
