IADR Abstract Archives
Core Fracture Toughness of Six Lab Multilayered Zirconias
Objectives: Objective of this stidy was to measure the central core fracture toughness of six commercially available lab zirconia in the center of the zirconia pucks.
Methods: Six zirconias were tested: Aidite® 3D Pro Multilayer Zirconia (Group 1), KatanaTM Zirconia YML (Group 2), KatanaTM Zirconia HTML Plus (Group 3), Ceramill® Zolid fx Multilayer (Group 4), Cercon® xt ML (Group 5), and IPS e.max® ZirCAD Prime (Group 6). Eight Flexure bars (36 mm x 4 mm x 3 mm after sintering) were milled centered in height using a PrograMill PM7 with PrograMill CAM V5.0.017.00 software. Milled the bars were desprued and cleaned, they were sintered according to the manufacturer's instructions. The fully sintered bars were lined with 3 equally spaced indents across the center of the bar using 5 or 10 kg loads using a Marco Vickers Hardness Tester. The bars were then placed in bridge indentation precracking fixture as described in ASTM Standard C 1421 and loaded in an Instron Universal testing machine (33R4204) at a crosshead speed of 0.20 mm/min until a crack was heard or until 10 kN. Specimen were backlit to examine for a crack. If no crack was observed, the specimen was loaded again until a crack was observed. Specimens were loaded in a 30 mm 3-point flexure fixture until failure at a cross-head speed of 1 mm/min. After fracture, three equa-spaced measurements were obtained from the fractured at 80x using an Olympus SZX12 optical microscope.
The fracture toughess was calculated using:
KIC=(PfS/bW3/2)f(a/W)
where
f(a/W)=(3/2)(a/W)1/2(1.964-2.837a/W+13.711a2/W2- 23.250a3/W3+24.129a4/W4)
where
Pf=Failure load(N), S=Support span(m), B=Thickness(m), W=Width(m) and a=Precrack length
The averages were then calculated with standard deviations.
Results: The fracture toughness, KIC(MPa●m0.5), for each group is:Group 1: 4.15±0.17; Group 2: 4.97±0.15; Group 3: 5.06±0.16; Group 4: 3.18±0.19; Group 5: 3.89±0.26; and Group 6: 5.11±0.14. Using ANOVA (p≤0.05), no statistical difference was found between Groups 2,3 and 6 which were higher than Groups 1,4, and 5.. Groups 1 and 5 was startistically higher than Group 4.
Conclusions: Within the limitations of this study, Katana YML, Katana HTML Plus and IPS e.max ZirCAD Prime had higher core fracture toughness values than Aidite, Ceramill and Cercon for multilayered dental zirconia pucks.
Methods: Six zirconias were tested: Aidite® 3D Pro Multilayer Zirconia (Group 1), KatanaTM Zirconia YML (Group 2), KatanaTM Zirconia HTML Plus (Group 3), Ceramill® Zolid fx Multilayer (Group 4), Cercon® xt ML (Group 5), and IPS e.max® ZirCAD Prime (Group 6). Eight Flexure bars (36 mm x 4 mm x 3 mm after sintering) were milled centered in height using a PrograMill PM7 with PrograMill CAM V5.0.017.00 software. Milled the bars were desprued and cleaned, they were sintered according to the manufacturer's instructions. The fully sintered bars were lined with 3 equally spaced indents across the center of the bar using 5 or 10 kg loads using a Marco Vickers Hardness Tester. The bars were then placed in bridge indentation precracking fixture as described in ASTM Standard C 1421 and loaded in an Instron Universal testing machine (33R4204) at a crosshead speed of 0.20 mm/min until a crack was heard or until 10 kN. Specimen were backlit to examine for a crack. If no crack was observed, the specimen was loaded again until a crack was observed. Specimens were loaded in a 30 mm 3-point flexure fixture until failure at a cross-head speed of 1 mm/min. After fracture, three equa-spaced measurements were obtained from the fractured at 80x using an Olympus SZX12 optical microscope.
The fracture toughess was calculated using:
KIC=(PfS/bW3/2)f(a/W)
where
f(a/W)=(3/2)(a/W)1/2(1.964-2.837a/W+13.711a2/W2- 23.250a3/W3+24.129a4/W4)
where
Pf=Failure load(N), S=Support span(m), B=Thickness(m), W=Width(m) and a=Precrack length
The averages were then calculated with standard deviations.
Results: The fracture toughness, KIC(MPa●m0.5), for each group is:Group 1: 4.15±0.17; Group 2: 4.97±0.15; Group 3: 5.06±0.16; Group 4: 3.18±0.19; Group 5: 3.89±0.26; and Group 6: 5.11±0.14. Using ANOVA (p≤0.05), no statistical difference was found between Groups 2,3 and 6 which were higher than Groups 1,4, and 5.. Groups 1 and 5 was startistically higher than Group 4.
Conclusions: Within the limitations of this study, Katana YML, Katana HTML Plus and IPS e.max ZirCAD Prime had higher core fracture toughness values than Aidite, Ceramill and Cercon for multilayered dental zirconia pucks.