Exploring Needle-Like Zinc Oxide Nanostructures for Improving Dental Resin Sealers: Design and Evaluation of Antibacterial, Physical and Chemical Properties

This study aimed to evaluate the effect of needle-like zinc oxide nanostructures (ZnO-NN) on the physical, chemical, and antibacterial properties of experimental methacrylate-based dental sealers. ZnO-NN was synthesized and characterized. ZnO-NN was added to a co-monomer blend at 20, 30, and 40 wt.%. One group without ZnO-NN was used as a control. The dental resin sealers were evaluated for their flow, film thickness, water sorption, solubility, radiopacity, degree of conversion (DC), dental-sealer interface characterization via micro-Raman, and antibacterial activity. ZnO-NN presented a mean needle diameter of 40 nm and 16 m(2)/g of surface area. There was no difference among groups containing ZnO-NN regarding their flow. The ZnO-NN addition significantly increased the film thickness. Water sorption and solubility tests showed no difference among groups. The radiopacity increased, and DC decreased with higher concentrations of ZnO-NN. Micro-Raman suggested that ZnO-NN was in close contact with root canal dentin. Overall, the incorporation of ZnO-NN provided an antibacterial effect against Enterococcus faecalis without a significant detrimental impact on the physical and chemical functionality of the material. The use of ZnO-NN as an inorganic filler is a potential application within dental materials intended for root canal treatment.