Mechanical and chemical properties of a 3-dimension–printed denture base resin obtained by varying digital light processing and liquid crystal display printing angles

The authors evaluate the effect of different printing technologies (digital light processing [DLP], liquid crystal display [LCD]), and different printing angles (0°, 45°, 90°) on the mechanical (flexural strength [FS] and Vickers hardness number [VHN]) and chemical properties (degree of conversion [DC], surface microstructural, and glass transition temperature [Tg]) of a 3-dimension–printed denture base resin. Three-dimension–printed specimens (priZma 3D Bio Denture; MakertechLabs) were grouped: LCD0°, LCD45, LCD90°, DLP0°, DLP45°, and DLP90°. Thirty specimens were fabricated per group, for FS (12), VHN (12), DC (2), x-ray excited photoelectron spectroscopy (2), and Tg (2). For FS (MPa), a significant difference (SD) was found between DLP (93 [15]) and LCD (82 [14]) (2-way analysis of variance, P < .001), and 0° (79 ± 9), 45° (99 ± 12), and 90° (84 [16]) (Tukey test, P < .05). For VHN, no significant effects were detected (2-way analysis of variance, P >.05). Tg ranged from 80 °C through 100 °C for all groups. The highest means (SD) of DC were achieved for the specimens printed at 0° (DLP, 86.8 [3.7]%; LCD, 89.6 [0.3]%). The DLP system and 45° presented the highest FS, whereas the printing angle of 0° exhibited the highest DC. Considering that both systems (DLP, LCD) showed results above the threshold of 65 MPa for FS of denture base materials, and that LCD is a faster and lower-cost system, this technology could also be suggested for printing denture bases.