IADR Abstract Archives
Fracture Toughness of Conventional, Milled and 3D-Printed Denture Base Materials
Objectives: To determine and compare the fracture toughness (KIC) of conventional, CAD/CAM and 3D-printed denture base materials.
Methods: Conventional (Lucitone 199), CAD/CAM (Lucitone 199 CAD) and 3D-print (Lucitone Digital Print) denture base materials produced by Dentsply Inc. were used in this study. Fracture toughness was determined using the notchless triangular prism (NTP) specimen KIC test. Twenty NTP specimens [(6x6x6x12) mm)] were prepared from each material by either cutting and polishing or by printing. The specimens were conditioned in 37 °C water for 7 days, as per ISO 20795-1. Testing was done after introducing a 0.1mm deep defect using 200 µm thick surgical blade. A custom mounting jig was used to secure the sample in the two halves of the sample holder, replicating the chevron-notch short rod specimen configuration. The test assembly was secured in custom designed grips, attached to a universal testing machine (Instron 4301) equipped with a 1 kN Instron load cell and controlled by Bluehill 2 software. The test assembly was loaded in tension at a crosshead speed of 0.1 mm/min until crack arrest or failure. The maximum recorded load was used to calculate KIC (in MPa.m1/2) using the equation,
KIC =(Pmax x Y*min) / (DW½)
where Y*min = minimum value of the dimensionless stress intensity factor coefficient (28 for NTP test), D = specimen diameter (12 mm), and W = specimen length (10.4 mm).
Statistical analysis was performed using ANOVA followed by Scheffé multiple mean comparisons (a=0.05).
Results: The mean KIC (MPa.m1/2) of printed denture base (4.13 ± 0.48) was significantly higher than that of conventional (2.09 ± 0.13) and milled (1.96 ± 0.14) denture bases, which were not statistically different.
Conclusions: Printed denture bases exhibit higher KIC and are more resistant to crack propagation than conventional and milled denture bases.
Methods: Conventional (Lucitone 199), CAD/CAM (Lucitone 199 CAD) and 3D-print (Lucitone Digital Print) denture base materials produced by Dentsply Inc. were used in this study. Fracture toughness was determined using the notchless triangular prism (NTP) specimen KIC test. Twenty NTP specimens [(6x6x6x12) mm)] were prepared from each material by either cutting and polishing or by printing. The specimens were conditioned in 37 °C water for 7 days, as per ISO 20795-1. Testing was done after introducing a 0.1mm deep defect using 200 µm thick surgical blade. A custom mounting jig was used to secure the sample in the two halves of the sample holder, replicating the chevron-notch short rod specimen configuration. The test assembly was secured in custom designed grips, attached to a universal testing machine (Instron 4301) equipped with a 1 kN Instron load cell and controlled by Bluehill 2 software. The test assembly was loaded in tension at a crosshead speed of 0.1 mm/min until crack arrest or failure. The maximum recorded load was used to calculate KIC (in MPa.m1/2) using the equation,
KIC =(Pmax x Y*min) / (DW½)
where Y*min = minimum value of the dimensionless stress intensity factor coefficient (28 for NTP test), D = specimen diameter (12 mm), and W = specimen length (10.4 mm).
Statistical analysis was performed using ANOVA followed by Scheffé multiple mean comparisons (a=0.05).
Results: The mean KIC (MPa.m1/2) of printed denture base (4.13 ± 0.48) was significantly higher than that of conventional (2.09 ± 0.13) and milled (1.96 ± 0.14) denture bases, which were not statistically different.
Conclusions: Printed denture bases exhibit higher KIC and are more resistant to crack propagation than conventional and milled denture bases.