Water Sorption and Solubility Behavior of Provisional Restorative Materials Fabricated by Conventional, CAD/CAM, and 3D printing Methods

Aims: The present study aimed to assess and compare the levels of water sorption and solubility of provisional restorative materials manufactured by conventional, CAD/CAM, or 3D printing methods. Materials and Methods: A total of forty-two circular samples of (15mm × 2 mm diameter, thickness respectively) respectively were fabricated and divided into three groups (n= 7 for each sample): Group A: 3D-printed at 0°, 15°, and 45° build angles by using a digital light processing (DLP) printer (Creality LD-006, China) with (FREEPRINT® temp resin, Jermany), Group B: CAD/CAM milled at high (5-8m) and low (8-15m) speed by using pre-polymerized PMMA blocks (Dental Direct polyX ML, Jermany) using a 5-axis milling machine (Zahndent, China), Group C: Conventional self-curing interim resin IMICRYL® (Imident powder. Turky). All samples were tested for water sorption and solubility tests. The collected data were statistically analyzed using one-way ANOVA and independent t-tests, with the significance level set at 0.05. Results: The results of the one-way ANOVA test indicated a statistically significant variation (P ≤ 0.01) in water sorption values between 3D-printed provisional restorations fabricated with build angles of 0°, 15°, and 45°, but not in water solubility, for which there was no significant difference (P > 0.05). However, Independent samples t-tests showed no statistically significant difference (P > 0.05), indicating that the variation in milling speeds, low (8-15 m/min) versus high (5-8 m/min) had no detectable effect on water sorption or solubility in the CAD/CAM groups. Comparing all the fabrication processes, ANOVA indicated significant differences (P ≤ 0.05) in both parameters. Duncan’s test showed the highest water sorption in 3D-printed 0° (1.0029 μg/mm³), followed by 15° (0.878 μg/mm³) and 45° (0.8177 μg/mm³). CAD/CAM low-speed milling had 1.1501 μg/mm³ and high-speed 1.1069 μg/mm³, while conventional PMMA had 1.0078 μg/mm³. For water solubility, conventional PMMA had the highest mean value (0.0887 μg/mm³), and the 3D-printed 0° group had the lowest (0.0183 μg/mm³). Conclusion: Results indicate that fabrication method and build orientation influence the water sorption and water solubility of provisional restorative materials. 3D-printed restorations, particularly those printed at a 0° build angle, exhibited the least solubility and good water resistance compared to CAD/CAM and control PMMA groups. The results demonstrate the potential of optimized 3D printing parameters in producing long-lasting, water-resistant provisional restorations.