Radiopacity, pH and antimicrobial activity of Portland cement associated with micro- and nanoparticles of zirconium oxide and niobium oxide

Abstract

The aim of this study was to evaluate some properties of the calcium silicate materials Mineral Trioxide Aggregate (MTA) and Portland cement (PC) with microparticulated (micro) and nanoparticulated (nano) zirconium oxide (ZrO₂) or niobium oxide (Nb₂O₅). The experimental materials: White PC (PC), MTA-Angelus^® (MTA), PC+ZrO₂micro, PC+ZrO₂nano, PC+Nb₂O₅micro and PC+Nb₂O₅nano were submitted to radiopacity and pH evaluations. Furthermore, the antimicrobial activity against different microorganisms was assessed by agar diffusion test. MTA presented higher radiopacity than other materials. However, all materials except PC presented higher radiopacity than recommended by ISO/ADA. MTA promoted higher pH values in all analyzed periods (p≤0.05). At the initial periods, PC and PC+ZrO₂micro showed pH similar to MTA. All materials showed antimicrobial activity against the evaluated microorganisms. In conclusion, ZrO₂ and Nb₂O₅ could be alternative radiopacifiers to be added to calcium silicate materials.