Mechanical and optical effects of post-curing time and device type in two 3D-printed resin systems.

Aim: The aim of this study was to investigate the effect of post-polymerization time and curing device type on the surface roughness, microhardness and color change of 3D printed permanent resin materials.

Materials And Methods: In this study, permanent resin samples with a layer print thickness of 50 μm and dimensions of 10 × 2 mm3 were produced on SLA and DLP printers. The samples were post-polymerized in blue LED and UV LED curing devices for 10, 20, 40 and 60 min. Initial surface roughness, microhardness and color values of all polymerized samples were measured. The samples were then aged (5000 cycles) and surface roughness, microhardness and color values were measured again. Data were evaluated using two-way analysis of variance (ANOVA) and Tukey post hoc test (p < 0.05).

Results: There was no statistically significant difference in surface roughness when the samples produced in SLA and DLP printer were polymerized using blue LED and UV LED curing device for different durations (p > 0.05). The samples produced in SLA printer showed higher microhardness value when polymerized with UV LED for longer time (p < 0.05). There was no statistically significant difference in the microhardness values of DLP samples when polymerized with blue LED and UV LED (p > 0.05). When the samples produced in SLA and DLP printer were polymerized using blue LED and UV LED curing device for different durations, the color change and whiteness index increased as the post-polymerization time increased (p < 0.05). The surface roughness of the samples after aging did not change statistically significantly, while the microhardness value decreased (p < 0.05).

Conclusions: The post-polymerization time and the type of polymerization device do not affect the surface roughness of the 3D printed samples, but increase the microhardness value. Post-polymerization time increases the color change and whiteness index values of the samples. Post-polymerization of 3D printer permanent resin materials has an effect on the mechanical and optical properties of the material.

Clinical Significance: The post polymerization time of 3D resin materials and the type of curing device change the microhardness, color change and surface roughness of the material. This may affect the clinical success of the restoration.