Radiopacity of glass ionomer dental materials

The radiopacity of glass ionomer dental materials is quite variable. The use of a poorly radiopaque material as a base under other restorative materials can mislead the dentist to a diagnosis of recurrent decay. This study investigates the radiopacity of these materials and proposes a minimal radiopacity under which a material should not be used as a base or liner. All base, liner, and core formulations of glass ionomer under investigation were more radiopaque than dentin. All restorative and luting formulations of glass ionomer under investigation were less radiopaque than dentin and therefore should be avoided as bases or liners.