Influence of ZrO Nanoparticle Addition on the Optical Properties of Denture Base Materials Fabricated Using Additive Technologies.

This study investigated the translucency of 3D-printed denture base resins modified with zirconium dioxide nanoparticles (ZrONPs) under thermal cycling. A total of 110 specimens were fabricated and divided into 3 groups according to the materials, i.e., heat-polymerized resin, and 3D-printed resins (NextDent, and ASIGA). The 3D-printed resins were modified with 0, 0.5, 1, 3, and 5 wt.% of ZrONPs. All the specimens were subjected to 5000 thermal cycles. The translucency was measured using a spectrophotometer. The results showed that the heat-polymerized resin had considerably higher translucency than the 3D-printed resins. Compared to the unmodified group, the translucency decreased significantly after adding 5% ZrONPs to NextDent and 3% ZrONPs to ASIGA resins. The highest translucency was achieved for NextDent by adding 0.5% ZrONPs and for ASIGA without any ZrONPs. It was found that the average concentration level in ASIGA was significantly higher than that in NextDent. These findings revealed that 3D-printed resins have lower translucency than heat-polymerized acrylic resin, and adding ZrONPs at low concentrations did not affect the translucency of the 3D-printed resins. Therefore, in terms of translucency, 3D-printed nanocomposite denture base resins could be considered for clinical applications when ZrONPs are added at low concentrations.