Radiopaque dental adhesive with addition of niobium pentoxide nanoparticles

Radiopacity is an important property of dental adhesives, because it allows the adhesive resin to be in contrast with the tooth structure and other restorative materials. This study aimed to develop a radiopaque experimental adhesive resin through the addition of niobium pentoxide (Nb 2 O 5 ) particles. The effects of adding different concentrations of Nb 2 O 5 nanoparticles synthesized by microwave-assisted hydrothermal synthesis (MHS) were compared to the commercial Nb 2 O 5 microparticles. The experimental adhesive resin was formulated by mixing bisphenol A glycidyl methacrylate (Bis-GMA), 2-hydroxyethyl methacrylate (HEMA), camphorquinone (CQ) and ethyl 4-(dimethylamino)benzoate (EDAB). Experimental adhesive resins were evaluated by the radiopacity, degree of conversion, Knoop microhardness, translucency parameter, depth of cure, viscosity, and sedimentation rate. Synthesized Nb 2 O 5 showed hexagonal structure and nanoneedles aggregates in form of nanoflowers. The incorporation of Nb 2 O 5 nanoparticles into the dental adhesive resin showed high dispersion stability and improved the radiopaque properties.