IADR Abstract Archives
Wear, enamel wear, strength and hardness of CAD/CAM materials
Objectives: To measure the mechanical properties of several materials used for CAD/CAM milling, including lithium dislicate (e.max), lithium silicate/zirconia (Celtra Duo), 3 resin-ceramic hybrids (Cerasmart, Lava Ultimate, Enamic), and a composite resin (Paradigm MZ100).
Methods: CAD/CAM blocks were sectioned into 2.5mmx2.5mmx10mm bars for flexural strength testing and 4mm thick blocks for hardness and wear testing. E.max specimens were sintered. Flexural strength specimens (n=10) were tested at a 1mm/min crosshead speed in a three-point bending fixture in a universal testing machine. Vickers microhardness (n=2, 5 readings per specimen) was measured with a 1kg load and a 15 second dwell time. The CAD/CAM materials as well as labial surfaces of human incisors were mounted into the modified Alabama wear testing device. Cusps of human premolars were mounted as antagonists. The specimens were tested for 400,000 cycles of wear simulation at 20N force, 2mm sliding distance, 1 Hz frequency, and 33% glycerine lubrication. Volumetric wear and opposing enamel wear were measured with non-contact profilometry. Data were analyzed with 1-way ANOVA and Tukey post-hoc analysis (alpha=0.05). Wear specimens were observed with SEM.
Results: Materials with different superscripts in each column are significantly different. E.max, Celtra Duo, Enamic, and enamel demonstrated signs of abrasive wear, whereas other materials demonstrated signs of fatigue.
Conclusions: The mechanical properties of new CAD/CAM materials vary based on their microstructure.
Methods: CAD/CAM blocks were sectioned into 2.5mmx2.5mmx10mm bars for flexural strength testing and 4mm thick blocks for hardness and wear testing. E.max specimens were sintered. Flexural strength specimens (n=10) were tested at a 1mm/min crosshead speed in a three-point bending fixture in a universal testing machine. Vickers microhardness (n=2, 5 readings per specimen) was measured with a 1kg load and a 15 second dwell time. The CAD/CAM materials as well as labial surfaces of human incisors were mounted into the modified Alabama wear testing device. Cusps of human premolars were mounted as antagonists. The specimens were tested for 400,000 cycles of wear simulation at 20N force, 2mm sliding distance, 1 Hz frequency, and 33% glycerine lubrication. Volumetric wear and opposing enamel wear were measured with non-contact profilometry. Data were analyzed with 1-way ANOVA and Tukey post-hoc analysis (alpha=0.05). Wear specimens were observed with SEM.
Results: Materials with different superscripts in each column are significantly different. E.max, Celtra Duo, Enamic, and enamel demonstrated signs of abrasive wear, whereas other materials demonstrated signs of fatigue.
Conclusions: The mechanical properties of new CAD/CAM materials vary based on their microstructure.