Effect of Different Vat Polymerization Techniques on Physicomechanical and Biological Properties of 3d-Printed Denture Base

The utilization of three-dimensional (3D) printing in dentistry for denture base
fabrication is rapidly gaining traction in recent years. To date, a wide range of 3D
printing technologies and materials can be utilized for the fabrication of denture bases.
However, there is a lack of understanding of the effect of printability, mechanical,
physical, and biological properties of the 3D-printed denture base upon fabricating with
different vat polymerization techniques. This study was carried out to elucidate the
effect of different vat polymerization techniques in fabricating denture bases. In this
study, the NextDent denture base resin was printed with stereolithography (SLA),
digital light processing (DLP), and light-crystal display (LCD) techniques and
underwent the same post-processing procedure. One-way ANOVA and Tukey’s post hoc
were used to analyze the data statistically. The results showed that the greatest flexural
strength was exhibited by the SLA (150.8 ± 7.93 MPa) , followed by the DLP and
LCD. This trend was consistent in fracture toughness and microhardness, with SLA
demonstrating superior strength, followed by DLP and LCD. Notably, the water
sorption and solubility of the DLP are significantly higher (p < 0.05) than other groups
(31.51 ± 0.92 μg
mm3) and 􁉀5.32 ± 0.61 μg
mm3􁉁, respectively. SLA demonstrated the
highest overall mechanical strength among all tested groups, albeit at a slower printing
rate, owing to its ability to achieve a higher degree of conversion. Surface morphology
analysis revealed no discernible differences after undergoing thorough mechanical
polishing, indicating that the layered structure was confined to the outer surface.
However, the most Candida albicans adhesion was also found in SLA (221.94 ±
65.80 CFU/ml) probably due to its higher surface roughness along the successive
layers. Nonetheless, all denture bases fabricated with different vat polymerization did
not demonstrate any cytotoxic effect on the Human Gingiva Fibroblast. In conclusion,
this study confirmed that the NextDent denture base resin designed for DLP can be
printed with different vat polymerization techniques and all tested groups met the ISO
requirement aside from the water solubility. SLA exhibited the greatest mechanical
strength while the DLP showed the lowest microbial adhesion.