Comparison and evaluation of the radiopacity of different posterior composites

The purpose of this research was to test the radiopacity of both bulk-fill and traditional composite resin materials via a digital radiography system. Additionally, it tested how the radiopacity of these restorative materials compared to the radiopacity of natural enamel and dentin. Bulk-fill and conventional composite resins that were available for use in clinical settings were evaluated. Ten disc-shaped samples of each type of composite material were created; they were all 1 mm thick, and 5 mm in diameter. A 11-step aluminum wedge was used as a reference standard, providing incremental thicknesses between 1 and 11 mm. Each composite sample, along with an aluminum wedge and a tooth segment (to simulate the anatomy of a tooth), were arranged on a PSP (Photo-Stimulable Phosphor Plate) imaging plate to be exposed with a dental radiography device. The digital images produced by the imaging plate were then analyzed using image analysis software, which provided average gray-value readings. Three separate readings for each composite material, tooth structure, and aluminum wedge were made to produce the average gray-value reading. These readings were then converted into aluminum equivalent thicknesses. All composite-based restorative materials exhibited radiopacity values exceeding those of dentin. Among the tested materials, Filtek One Bulk Fill presented the greatest radiopacity. Only Estelite Bulk Fill Flow and EverX Flow demonstrated radiopacity levels below that of enamel, whereas the other seven composites displayed radiopacity comparable to or greater than enamel. When evaluated with a digital radiography system, all restorative materials examined met the radiopacity requirements of ‘International Organization for Standardization’ (ISO) and ‘American National Standards Institute/American Dental Association’ (ANSI/ADA).