Radiopacity evaluation of bis-GMA/TEGDMA/opaque mineral filler dental composites

The purpose of this work was to determine radiopacity values of composites based on (Bis-GMA/ TEGDMA) monomers, at varying monomer compositions: (25/75), (50/50), and (75/25), mixed with five different radiopacifying filler agents: BaO, BaSO4, La2O3, ZrO2, and SrO at varying loadings ranging from 0 to 80 wt %. The radiopacity of four commercial dental composites were also evaluated and used as a comparative data. Following standard radiographic technique, X-ray radiography of 2.5 mm thickness dental composite specimens along with pure aluminum step-wedge, a reference, were performed. The optical density of specimens was measured using a transmission densitometer and the radiopacity values of samples were expressed in term of equivalent thickness of aluminum per mm thickness of material. The lanthanum oxide filler containing composites, which is a new radiopacifying agent, exhibited the greatest radiopacity levels than all other composites, for all monomer and filler loadings studied. The radiopacity values of these composites were greater than that of human dental enamel. Strontium oxide containing composites were less radiopaque than other materials especially in the case of composites based on (Bis-GMA/TEGDMA): (25/75). The composites containing more than 10 wt % of BaO, BaSO4, and ZrO2 for monomer compositions of (75/25) and (50/50) had radiopacity values greater than that of enamel. (c) 2007 Wiley Periodicals, Inc.