IADR Abstract Archives
Cyclic Loading Fatigue Affects Fracture Toughness of CAD/CAM Restorative Materials
Objectives: To compare the effect of cyclic loading fatigue on fracture toughness (K1C) of contemporary dental restorative CAD/CAM materials.
Methods: Five commercially available CAD/CAM restorative materials were included in this study: Lava™ Ultimate Restorative (3M ESPE), IPS Empress® CAD (Ivoclar-Vivadent), Enamic® (VITA), IPS e.max® CAD (Ivoclar-Vivadent), and CERASMART™ (GC Dental). Polished rectangular bars 4×2×14mm (n=30) were prepared from mill blocks for each material. A single notch (0.5-1mm in depth, 0.5mm width) was made at the center of the non loading (tensile) edge. Ten specimens per group for each material were randomly selected for 1) static mode, 2) 100k cyclic loads, and 3) 200k cyclic loads. Fatigue was performed on the specimens in three point bending mode at a peak load of 40N and a frequency of 1Hz in a pneumatic driven cyclic loading machine. The surviving bars after the fatigue treatment were subjected to a three-point flexural test in a universal testing machine (Instron 5566A). K1C values were determined using ‘single-edge-pre-crack-beams’ (SEPB) method. Results were analyzed via ANOVA with Tukey’s HSD test or least square regression model using JMP Pro 12.0.
Results: Figure 1 shows mean fracture toughness (K1C) of the material tested in static mode, 100k cycles, and 200k cycles of fatigue. The Cerasmart and Lava Ultimate groups exhibited higher K1C values after cyclic loading. Empress was not affected by fatigue. The e.max CAD showed higher values and higher variance after 100K cycles and significantly lower K1C values after 200k loading. Enamic exhibited no significant difference after fatigue compared to the static group.
Conclusions: Ceramics and composite CAM/CAM materials showed different trends of K1C after cyclic loading fatigue.
Methods: Five commercially available CAD/CAM restorative materials were included in this study: Lava™ Ultimate Restorative (3M ESPE), IPS Empress® CAD (Ivoclar-Vivadent), Enamic® (VITA), IPS e.max® CAD (Ivoclar-Vivadent), and CERASMART™ (GC Dental). Polished rectangular bars 4×2×14mm (n=30) were prepared from mill blocks for each material. A single notch (0.5-1mm in depth, 0.5mm width) was made at the center of the non loading (tensile) edge. Ten specimens per group for each material were randomly selected for 1) static mode, 2) 100k cyclic loads, and 3) 200k cyclic loads. Fatigue was performed on the specimens in three point bending mode at a peak load of 40N and a frequency of 1Hz in a pneumatic driven cyclic loading machine. The surviving bars after the fatigue treatment were subjected to a three-point flexural test in a universal testing machine (Instron 5566A). K1C values were determined using ‘single-edge-pre-crack-beams’ (SEPB) method. Results were analyzed via ANOVA with Tukey’s HSD test or least square regression model using JMP Pro 12.0.
Results: Figure 1 shows mean fracture toughness (K1C) of the material tested in static mode, 100k cycles, and 200k cycles of fatigue. The Cerasmart and Lava Ultimate groups exhibited higher K1C values after cyclic loading. Empress was not affected by fatigue. The e.max CAD showed higher values and higher variance after 100K cycles and significantly lower K1C values after 200k loading. Enamic exhibited no significant difference after fatigue compared to the static group.
Conclusions: Ceramics and composite CAM/CAM materials showed different trends of K1C after cyclic loading fatigue.
2634003_File000000.jpg