[Shiau-ROC TAIWAN-O-5] Enhancing mechanical properties of photopolymer denture base resins by the incorporation of cellulose nanofibers (CNF)
[Abstract]
Objective
3D printed materials face strength challenges [1]. Traditional reinforcements lack sustainability, but cellulose nanofibers (CNF) from wood pulp offer high strength and eco-friendliness [2]. Therefore, the purpose of this study was to investigate the effect of CNF addition on improving the mechanical properties of denture base photopolymer resins.
Methods
Cellulose nanofibers (WFo-UNDP, Sugino machine) were added to photopolymer resins (dima Print Denture Base, Kulzer) at concentrations of 0, 0.5, 1.0, 1.5, and 2.0 wt%. The test specimen was printed using a DLP 3D printer (cara Print 4.0, Kulzer) with a printing direction of 0° and a printing layer thickness of 100 μm. After printing, the test pieces were washed with isopropanol and post-polymerized. After polishing, specimens were immersed in distilled water at 37±1°C for 24 hours. The three-point bending test, using a universal testing machine (AG-Xplus, Shimadzu), assessed flexural strength (FS) and flexural modulus (FM) at a 50 mm fulcrum distance and 1 mm/min crosshead speed. Vickers hardness (VH) was measured with a hardness machine (MVK-H2, Akashi) under a 300-gf load and a 15-second dwell time. Statistical analysis was performed by Tukey's multiple comparison test (α=0.05).
Results and Discussion
FS was significantly higher in the 0.5-2.0 wt% group and VH was significantly higher in the 1.0 and 1.5 wt% groups compared to the control group. FM was not significantly different among all groups. Despite an upward trend in VH with increasing CNF addition, a significant decrease was observed at 2.0 wt%. A similar pattern was also observed in FS. The phenomenon was suggested to occur because CNF forming a mesh structure that strengthens the FS and VH in the DLP denture base resin [2]. It was concluded that, under limited conditions, the addition of 1.0 and 1.5 wt% CNF to the denture base improves mechanical properties.
References
1) Altarazi A, Haider J, Alhotan A, et al. 3D printed denture base material: The effect of incorporating TiO2 nanoparticles and artificial ageing on the physical and mechanical properties. Dent Mater 2023; 39
2) Li T, Chen C, Brozena AH, et al. Developing fibrillated cellulose as a sustainable technological material. Nature 2021; 590
Objective
3D printed materials face strength challenges [1]. Traditional reinforcements lack sustainability, but cellulose nanofibers (CNF) from wood pulp offer high strength and eco-friendliness [2]. Therefore, the purpose of this study was to investigate the effect of CNF addition on improving the mechanical properties of denture base photopolymer resins.
Methods
Cellulose nanofibers (WFo-UNDP, Sugino machine) were added to photopolymer resins (dima Print Denture Base, Kulzer) at concentrations of 0, 0.5, 1.0, 1.5, and 2.0 wt%. The test specimen was printed using a DLP 3D printer (cara Print 4.0, Kulzer) with a printing direction of 0° and a printing layer thickness of 100 μm. After printing, the test pieces were washed with isopropanol and post-polymerized. After polishing, specimens were immersed in distilled water at 37±1°C for 24 hours. The three-point bending test, using a universal testing machine (AG-Xplus, Shimadzu), assessed flexural strength (FS) and flexural modulus (FM) at a 50 mm fulcrum distance and 1 mm/min crosshead speed. Vickers hardness (VH) was measured with a hardness machine (MVK-H2, Akashi) under a 300-gf load and a 15-second dwell time. Statistical analysis was performed by Tukey's multiple comparison test (α=0.05).
Results and Discussion
FS was significantly higher in the 0.5-2.0 wt% group and VH was significantly higher in the 1.0 and 1.5 wt% groups compared to the control group. FM was not significantly different among all groups. Despite an upward trend in VH with increasing CNF addition, a significant decrease was observed at 2.0 wt%. A similar pattern was also observed in FS. The phenomenon was suggested to occur because CNF forming a mesh structure that strengthens the FS and VH in the DLP denture base resin [2]. It was concluded that, under limited conditions, the addition of 1.0 and 1.5 wt% CNF to the denture base improves mechanical properties.
References
1) Altarazi A, Haider J, Alhotan A, et al. 3D printed denture base material: The effect of incorporating TiO2 nanoparticles and artificial ageing on the physical and mechanical properties. Dent Mater 2023; 39
2) Li T, Chen C, Brozena AH, et al. Developing fibrillated cellulose as a sustainable technological material. Nature 2021; 590