Radiopacity of Portland Cement and Calcium Silicate-Based Cement with Different Mixed Ratios of Radiopacifiers

Objective: The present study aimed to compare the radiopacity of Portland cement (PC) or calcium silicate-based cement (CSC) with different mixed radiopacifiers [bismuth oxide (BO)/ tantalum oxide (TO) and zirconium oxide (ZO)/barium sulfate (BS)] in a ratio of 1:1 or 1:2, with the 3 mm aluminium thickness (mmAl) acceptable value of ISO 6876:2012. Methods: PC and CSC mixed with different ratios of radiopacifiers were evaluated. One of high radiopacity radiopacifiers, BO or TO, was mixed with one of low radiopacity radiopacifiers, ZO or BS, in ratio of 1:1 and 1:2. PC or CSC powder, 1.6 g, was added into 0.4 g mixed radiopacifiers. Disc-shaped specimens of 1-mm thickness were prepared by mixing PC or CSC powder containing radiopacifiers with distilled water; the radiopacity was measured according to ISO 6876:2012. One-way ANOVA/Tukey's test and Welch ANOVA/Games-Howell test were used to compare the radiopacity among the groups. The significance level was set at 0.05. Results: PC groups had a higher radiopacity than CSC groups with the same radiopacifiers and ratio. BO groups showed higher radiopacity than TO groups. The groups with 1:1 ratio provided a higher radiopacity than 1:2 ratio groups (P>0.05). Conclusion: All tested radiopacifiers revealed adequate radiopacity ranging from 3.05-4.25 mmAl, except CSC with TO/BS in ratio of 1:2.