Evaluation of the Radiopacity of Luting Cements by Digital Radiography

Methods: Six specimens, 5 mm in diameter and 1 mm in height, were prepared for each material tested (Rely X ARC, Rely X U100, Rely X Unicem ; 3M ESPE, Nexus 2, Nexus 3; Kerr, Metacem; META, Breeze; Pentron Clinical and Zinc Phosphate; SpofaDental). The specimens were stored in a moist chamber at 37°C until completely set. After the material set, radiographs were made by using Kodak digital sensor (Eastman Kodak Co, Rochester, NY) alongside an aluminum stepwedge with variable thicknesses (from 1 to 13 mm, in 1-mm increments) that were used for reference. A Kodak 2100 intraoral x-ray unit was used, operating at 60 kV, 7 mA, and 0.20 second. These specimens were tested according to the international standards to compare their radiopacity to that of the aluminum stepwedge by using the equal-density area tool of the Kodak dental imaging software 6.7. Data were analyzed using analysis of variance and Tukey tests.

Results: Zinc Phosphate cement showed the highest radiopacity than all materials and dentin. Breeze showed the lowest radiopacity (p<0.05). There is no significant difference between radiopacity of Dentin and RelyX ARC, Nexus 2, Metacem (p>0.05). Among resin cements, radiopacity of Nexus 3 and RelyX Unicem were significantly higher than the other resin cements (p<0.05).

Conclusion: All materials showed radiopacity above the minimum recommended by the International Organization for standardization and the American National Standards /American Dental Association (ISO, ANSI/ADA). Breeze has less radiopacity when compared with Dentin.