Physicochemical properties of a calcium aluminate cement containing nanoparticles of zinc oxide

OBJECTIVES: This study evaluated the effect of different nanoparticulated zinc oxide (nano-ZnO) and conventional-ZnO ratios on the physicochemical properties of calcium aluminate cement (CAC). MATERIALS AND METHODS: The conventional-ZnO and nano-ZnO were added to the cement powder in the following proportions: G1 (20% conventional-ZnO), G2 (15% conventional-ZnO + 5% nano-ZnO), G3 (12% conventional-ZnO + 3% nano-ZnO) and G4 (10% conventional-ZnO + 5% nano-ZnO). The radiopacity (R(ad)), setting time (S(et)), dimensional change (D(c)), solubility (S(ol)), compressive strength (C(st)), and pH were evaluated. The nano-ZnO and CAC containing conventional-ZnO were also assessed using scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. Radiopacity data were analyzed by the 1-way analysis of variance (ANOVA) and Bonferroni tests (p < 0.05). The data of the other properties were analyzed by the ANOVA, Tukey, and Fisher tests (p < 0.05). RESULTS: The nano-ZnO and CAC containing conventional-ZnO powders presented particles with few impurities and nanometric and micrometric sizes, respectively. G1 had the highest R(ad) mean value (p < 0.05). When compared to G1, groups containing nano-ZnO had a significant reduction in the S(et) (p < 0.05) and lower values of D(c) at 24 hours (p < 0.05). The C(st) was higher for G4, with a significant difference for the other groups (p < 0.05). The S(ol) did not present significant differences among groups (p > 0.05). CONCLUSIONS: The addition of nano-ZnO to CAC improved its dimensional change, setting time, and compressive strength, which may be promising for the clinical performance of this cement.