Radiopacity and cytotoxicity of portland cement containing zirconia doped bismuth oxide radiopacifiers

Introduction This study evaluates the radiopacity and cytotoxicity of Portland cements containing a radiopacifier of bismuth oxide (Bi ₂O₃) with yttria-stabilized zirconia (YSZ) dopant. Methods Various radiopacifier powders of Bi₂O₃ with 0%, 15%, 30%, and 100% YSZ dopant were prepared by solid-state reaction at 700 C for 12 hours and characterized by x-ray diffraction. Portland cement/radiopacifier/calcium sulfate (75/20/5) were mixed and set by deionized water. Changes in radiopacity and in vitro cell viability of the hydrated cements were assessed. An average of 6 measured equivalent thickness of aluminum (N = 6) capable of producing similar radiographic density was recorded. The cytotoxicity of each material was determined in MC3T3 E1 cell-based methyl-thiazol-tetrazolium assay. Results The x-ray diffraction patterns of YSZ doped Bi₂O₃ are different from those of pure Bi₂O₃ and YSZ. The cement-containing radiopacifier of Bi₂O₃/YSZ (85/15) presented significantly greater radiopacity (P 2O₃. The mouse osteoblastic cell (MC3T3-E1) viabilities of these 2 groups were statistically similar (P 2O₃/YSZ (85/15) reveals higher radiopacity but similar cell viability when compared with pure Bi ₂O₃. It shows potential use as an alternative radiopacifier in root-end filling materials.