Influence of Nanoparticulated Silica Addition at 3D Printing Resin Composite

Objectives: The aim of this study was to evaluate the influence of nanofiller loading level on physico-chemical properties of a 3D printing resin.
Methods: An experimental resin was formulated with UDMA 70%wt, Bis-EMA 20%wt, and TEGDMA 10%wt. TPO and DFI, 2%wt, were added as photoinitiators. Colloidal silica (Aerosil OX50) was used as the filler component at 5%wt, 10%wt, and 20%wt for different groups. A group without nanofiller addition was used as control.Specimens were fabricated using an Anycubic Photon Mono 4K Liquid Cristal Display (LCD) printer, washed (5 minutes) with ethanol 96%, and post-polymerized in an UV curing unit (FormCure, Formlabs) for 2x20 minutes at 60oC. Viscosity was determined by a rheometer using 40 mm cone-and-plate geometry (n=3). The degree of conversion (DC)(n=5) was evaluated by FTIR-ATR and the polymerization kinetics was analyzed by PhotoDSC with 100mW/cm2 (n=3). The flexural strength (n=5) was performed according to ISO 4049:2019, at crosshead speed of 1mm/min. Data were analyzed by one-way ANOVA (α=0.05)
Results: The addition of colloidal silica in different concentrations increased the resin viscosity for all groups. The group G0% had the lowest DC value (82,48 ± 2,40%), while no difference was observed between groups G5%, G10%, and G20% (89,27 ± 1,46%; 91,06 ± 1,81%; 88,89±2,46%, respectively), p>0,05. As the nanofiller loading level increased, flexural strength increased ranging from G0%: 61,82 ± 1,65 MPa to G20%: 81,78 ± 3,14 MPa, p<0,05.
Conclusions: The addition of 10 and 20%wt colloidal silica increased mechanical properties of the experimental 3D printing resin.