Impact of Zr-Doped Bi(2)O(3) Radiopacifier by Spray Pyrolysis on Mineral Trioxide Aggregate

Mineral trioxide aggregates (MTA) have been developed as a dental root repair material for a range of endodontics procedures. They contain a small amount of bismuth oxide (Bi(2)O(3)) as a radiopacifier to differentiate adjacent bone tissue on radiographs for endodontic surgery. However, the addition of Bi(2)O(3) to MTA will increase porosity and lead to the deterioration of MTA’s mechanical properties. Besides, Bi(2)O(3) can also increase the setting time of MTA. To improve upon the undesirable effects caused by Bi(2)O(3) additives, we used zirconium ions (Zr) to substitute the bismuth ions (Bi) in the Bi(2)O(3) compound. Here we demonstrate a new composition of Zr-doped Bi(2)O(3) using spray pyrolysis, a technique for producing fine solid particles. The results showed that Zr ions were doped into the Bi(2)O(3) compound, resulting in the phase of Bi(7.38)Zr(0.62)O(12.31). The results of materials analysis showed Bi(2)O(3) with 15 mol % of Zr doping increased its radiopacity (5.16 ± 0.2 mm Al) and mechanical strength, compared to Bi(2)O(3) and other ratios of Zr-doped Bi(2)O(3). To our knowledge, this is the first study of fabrication and analysis of Zr-doped Bi(2)O(3) radiopacifiers through the spray pyrolysis procedure. The study reveals that spray pyrolysis can be a new technique for preparing Zr-doped Bi(2)O(3) radiopacifiers for future dental applications.