Mechanical, Surface and Physicochemical Properties of Nanozeolite-Modified 3D Printed Hybrid Ceramics at Varying
Ahmed A Holiel1,2, Yomna M Ibrahim3, Noha Morsy1
1Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt.
Objectives:
To evaluate nanozeolite (NZ)-modified 3D-printed hybrid ceramics at 0.25%, 0.5%, and 1% versus milled hybrid resin-ceramics, focusing on fracture toughness, surface roughness, microhardness, degree of conversion (DC), water sorption, and color stability.
Materials And Methods:
NZ was incorporated into 3D-printed ceramic-filled resin (VarseoSmile Crown Plus, VA) and tested alongside unmodified VA (control) and milled CAD-CAM ceramic (Vita Enamic, VE). Bars (18 × 3.6 × 1.8 mm) were prepared for fracture toughness, and discs (10 × 2 mm) for roughness, microhardness, water sorption, and color/translucency. Fracture toughness was measured by the single-edge notched beam (SENB) method, roughness and microhardness by profilometer and Vickers test, and DC by FTIR. Water sorption/solubility was gravimetrically measured, and ΔE00 and translucency parameter (TP) by spectrophotometry. Tests were conducted before and after thermocycling (1000 cycles, 5°C-55°C). Data were analyzed using ANOVA, Kruskal-Wallis, t-tests, and Wilcoxon signed-rank tests (p < 0.05).
Results:
VE exhibited the highest fracture toughness and microhardness, which decreased after thermocycling (p < 0.001). NZ-0.25% improved toughness versus VA both before and after aging (p = 0.04), while NZ-0.5% and 1% slightly reduced toughness but increased microhardness and decreased roughness after aging (p < 0.01). All NZ groups showed higher DC than control (p < 0.001). Thermocycling reduced toughness in VE and VA, but not NZ-VA. Water sorption and solubility were significantly lower in all NZ groups (p < 0.0001). ΔE00 remained < 1.8 for all groups after thermocycling, with 0.25% NZ-VA showing the most color stability and 1% NZ-VA showing minimal TP changes (p < 0.05).
Conclusion:
Milled hybrid ceramic (VE) outperformed printed hybrid ceramic (VA). Nanozeolite improved VA, with 0.25% providing the best balance of fracture toughness and microhardness, while preserving color and aging stability. Higher concentrations (0.5%-1%) mainly enhanced surface characteristics but added little to bulk properties and translucency.
Clinical Significance:
Nanozeolite integration at 0.25% enhances strength, durability, and color stability in 3D-printed hybrid ceramics, improving their reliability for dental restorations. Higher loadings enhance surface properties but may modestly reduce bulk toughness and translucency, relevant for clinical decision-making.
