Effects of different 3Y-TZP nanoparticle concentrations on reinforcing mechanical properties of 3D-printed resin...

To evaluate the impact of varying concentrations of 3 mol% yttria-stabilized tetragonal zirconia polycrystalline ceramic (3Y-TZP) nanoparticles on mechanical properties of three-dimensional (3D)-printed resins in stereolithography (SLA) technology.

A total of four groups (n = 6) of specimens were printed. Pure 3D-printed resin was used as the control group (0 wt%). For the experimental groups, modified 3Y-TZP nanoparticles were dispersed into 3D-printed resin at 1, 3, and 5 wt% concentrations to fabricate nanocomposites. Mechanical tests, including degree of conversion (DC), flexural strength, flexural modulus, fractography, and hardness, were evaluated and analyzed by one-way analysis of variance followed by the Games-Howell post-hoc test or Tukey post-hoc test (α = 0.05).

The DC of the control group showed the lowest value (p < 0.0001). The DC values peaked at the 5 wt% group, with no significant difference between the 3 wt% group. The flexural strength and modulus of the experimental groups were significantly higher than those in the control group. The addition of 1 and 3 wt% 3Y-TZP nanoparticles significantly improved the flexural strength and modulus (p < 0.05), while 5 wt% resulted in a significant decrease. The 1 wt% group showed the lowest hardness value. Maximum hardness value was observed in the 3 wt% group (p < 0.05). No significant difference was observed between the control and 5 wt% groups (p = 0.428).

Optimal mechanical properties were obtained with the 3 wt% group, indicating its potential as a dental material in clinical application.