IADR Abstract Archives
Impact of Nanofiller Fractions on Microfilled Resin Composite
Objectives: The aim of this study was to assess the impact of incorporating various weight fractions of nanometer-sized particulate fillers on specific properties of microfilled resin composite.
Methods: Microfilled resin composite was prepared by mixing 29 wt.% of resin matrix (BisGMA/TEGDMA) to the 71 wt.% of silane treated micrometer-sized (0.4 µm) particulate fillers. Then, various fractions of nanometer-sized (180 nm) fillers (0, 5, 10, 15, 20, 25, 30, 35 wt.%) were added gradually using high speed mixing machine. For each resin composite, flexural properties (n=8) were evaluated using a three-point bending test on a universal testing machine (ISO standard 4049). FTIR-spectrometry was used to calculate the degree of monomer conversion (DC%). Surface microhardess (Vickers) was also determined. Surface gloss was measured before and after polishing (paper grits: 4000). A two-body wear test was performed in a ball-on-flat configuration using a chewing simulator with 15000 cycles. A non-contact 3D optical profilometer was utilized to measure wear depth. ANOVA was applied to statistically interpret the results, and then the post hoc Tukey's analysis was performed.
Results: ANOVA revealed that fraction of nanofillers had significant effect (p<0.05) on flexural modulus, DC%, microhardness, gloss and wear depth. The group without nanofillers showed the highest DC% (56.6), gloss after polishing (76.2 GU) and wear resistance (24.2 µm) values. While the group with 35 wt.% of nanofillers had the highest flexural modulus (9 GPa) and microhardness (70 VH).
Conclusions: It is beneficial to add nanofillers to microfilled resin composite, however it is essential to carefully assess the proportion ratio. Optimizing different properties of resin composite at once with just one formulation is challenging.
Methods: Microfilled resin composite was prepared by mixing 29 wt.% of resin matrix (BisGMA/TEGDMA) to the 71 wt.% of silane treated micrometer-sized (0.4 µm) particulate fillers. Then, various fractions of nanometer-sized (180 nm) fillers (0, 5, 10, 15, 20, 25, 30, 35 wt.%) were added gradually using high speed mixing machine. For each resin composite, flexural properties (n=8) were evaluated using a three-point bending test on a universal testing machine (ISO standard 4049). FTIR-spectrometry was used to calculate the degree of monomer conversion (DC%). Surface microhardess (Vickers) was also determined. Surface gloss was measured before and after polishing (paper grits: 4000). A two-body wear test was performed in a ball-on-flat configuration using a chewing simulator with 15000 cycles. A non-contact 3D optical profilometer was utilized to measure wear depth. ANOVA was applied to statistically interpret the results, and then the post hoc Tukey's analysis was performed.
Results: ANOVA revealed that fraction of nanofillers had significant effect (p<0.05) on flexural modulus, DC%, microhardness, gloss and wear depth. The group without nanofillers showed the highest DC% (56.6), gloss after polishing (76.2 GU) and wear resistance (24.2 µm) values. While the group with 35 wt.% of nanofillers had the highest flexural modulus (9 GPa) and microhardness (70 VH).
Conclusions: It is beneficial to add nanofillers to microfilled resin composite, however it is essential to carefully assess the proportion ratio. Optimizing different properties of resin composite at once with just one formulation is challenging.