IADR Abstract Archives
Fracture Toughness of Ten Dental CAD/CAM Materials
Objectives: To test the fracture toughness, KIC, of ten commercially available CAD/CAM materials according to a modified ISO 6872_2015 method.
Methods:
Materials (n=8) tested in this study: Group-1:Tetric® CAD (Ivoclar Vivadent), Group-2:LavaTM Ultimate(3M ESPE), Group-3:Cerasmart®(GC), Group-4:ParadigmTM(3M ESPE), Group-5:Enamic®(Vita), Group-6:IPS Empress® CAD (Ivoclar Vivadent), Group-7:Celtra®Duo Unfired (Dentsply), Group-8:Celtra®Duo Fired(Dentsply), Group-9:n!ceTM(Straumann), and Group-10:IPS e.max® CAD(Ivoclar Vivadent). Fracture toughness was determined according to ASTM-C1421-10. Blocks were sectioned into bars (3mmx4mmx17mm). Groups-8 and 10 were fired per manufacturer’s instructions. An initial V-0.5mm notch was placed using a diamond saw. The V-notch was sharpened between 0.9-1.1mm using a razor blade using 6µm/3µm/1µm diamond paste. The specimens were loaded to failure in a three-point testing fixture (span-15mm) at a crosshead speed of 0.5mm/min in an Instron Universal testing machine. Notch depths were measured at three points using an optical microscope (50x) and averaged with no difference of 0.1 mm across the specimen. The relative V-notch depth was calculated (a/w~0.25). The precracked beam method was used to calculate fracture toughness (KIC):
KIC = g*[(Pf*Sx10-6)/(t*w3/2)]*[(3(a/w)1/2)/(2(1-a/w)3/2)]
g is {1.99-[(a/w)(1-a/w)]*[2.15-3.93(a/w)+2.7*(a/w)2]}/[1+2(a/w)]
Pf=failure load; s=span; t=thickness; w=width; a=average V-notch depth
Results: Data was analyzed using (ANOVA) and Tukey's post hoc analysis for statistical differences (p≤0.05) between groups.
Conclusions: Within the limitations of this study, IPS e.max CAD had the highest fracture toughness. Tetric CAD had the highest fracture toughness in the hybrid ceramic resin category of materials and has no statistical difference from Celtra Duo lithium silicate material.
Methods:
Materials (n=8) tested in this study: Group-1:Tetric® CAD (Ivoclar Vivadent), Group-2:LavaTM Ultimate(3M ESPE), Group-3:Cerasmart®(GC), Group-4:ParadigmTM(3M ESPE), Group-5:Enamic®(Vita), Group-6:IPS Empress® CAD (Ivoclar Vivadent), Group-7:Celtra®Duo Unfired (Dentsply), Group-8:Celtra®Duo Fired(Dentsply), Group-9:n!ceTM(Straumann), and Group-10:IPS e.max® CAD(Ivoclar Vivadent). Fracture toughness was determined according to ASTM-C1421-10. Blocks were sectioned into bars (3mmx4mmx17mm). Groups-8 and 10 were fired per manufacturer’s instructions. An initial V-0.5mm notch was placed using a diamond saw. The V-notch was sharpened between 0.9-1.1mm using a razor blade using 6µm/3µm/1µm diamond paste. The specimens were loaded to failure in a three-point testing fixture (span-15mm) at a crosshead speed of 0.5mm/min in an Instron Universal testing machine. Notch depths were measured at three points using an optical microscope (50x) and averaged with no difference of 0.1 mm across the specimen. The relative V-notch depth was calculated (a/w~0.25). The precracked beam method was used to calculate fracture toughness (KIC):
KIC = g*[(Pf*Sx10-6)/(t*w3/2)]*[(3(a/w)1/2)/(2(1-a/w)3/2)]
g is {1.99-[(a/w)(1-a/w)]*[2.15-3.93(a/w)+2.7*(a/w)2]}/[1+2(a/w)]
Pf=failure load; s=span; t=thickness; w=width; a=average V-notch depth
Results: Data was analyzed using (ANOVA) and Tukey's post hoc analysis for statistical differences (p≤0.05) between groups.
Conclusions: Within the limitations of this study, IPS e.max CAD had the highest fracture toughness. Tetric CAD had the highest fracture toughness in the hybrid ceramic resin category of materials and has no statistical difference from Celtra Duo lithium silicate material.