Fracture Toughness of Printed, Machined and Conventional Denture Base Materials

Objectives: To determine the fracture toughness and work of fracture of different types of denture base materials.
Methods: Specimens for fracture toughness and work of fracture of various denture base materials were prepared according to ISO 20795-1:2013 using single edge-notch bars pre-cracked according to the specification; 39.0 X 8.0 X 4.0 mm. Materials tested were: 1) Lucitone Digital Print (Dentsply-Sirona, United States), 2) Lucitone^â 199 Denture base disc (Dentsply-Sirona, United States), 3) Lucitone^â 199 (Dentsply Sirona, United States), and 4) DENTCA (Torrance, CA). All specimens were prepared following manufacturer’s instruction. Group 1 and 4 were printed using a Carbon 3D printer. Group 2 was sectioned from the disc and 3 by conventional processing . All specimens from each group were stored in water at 37±1°C for 7 days ± 2 hours before. Half of the specimens for each group were then conditioned in a separate water bath at 23±1°C for 60 ± 15 minutes before testing. The other half were tested in a chamber at 37±1°C . Fracture toughness was tested with Universal testing machine (Instron, United States). Means of fracture toughness and work of fracture values were analyzed using analysis of variance (ANOVA) and Tukey post hoc test (p<0.05).
Results: The average and standard deviation of fracture toughness and work of fracture of different denture base materials are shown in Table 1 and Table 2.
Conclusions: Fracture toughness and work of fracture of various denture base materials are significantly different. Elevated temperatures resulted in higher values for all tested materials except Dentca work of fracture.