Impact of Zr-Doped Bi₂O₃ Radiopacifier by Spray Pyrolysis on Mineral Trioxide Aggregate

• Main Authors: Tzu-Yu Peng, May-Show Chen, Ya-Yi Chen, Yao-Jui Chen, Chin-Yi Chen, Alex Fang, Bo-Jiun Shao, Min-Hua Chen, Chung-Kwei Lin
• Format: Article
• Language: English
• Published: MDPI AG 2021-01-01
• Series: Materials
• Subjects: mineral trioxide aggregate; radiopacifier; spray pyrolysis; zirconium-doped; bismuth oxide
• Online Access: https://www.mdpi.com/1996-1944/14/2/453

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 (Bi₂O₃) as a radiopacifier to differentiate adjacent bone tissue on radiographs for endodontic surgery. However, the addition of Bi₂O₃ to MTA will increase porosity and lead to the deterioration of MTA’s mechanical properties. Besides, Bi₂O₃ can also increase the setting time of MTA. To improve upon the undesirable effects caused by Bi₂O₃ additives, we used zirconium ions (Zr) to substitute the bismuth ions (Bi) in the Bi₂O₃ compound. Here we demonstrate a new composition of Zr-doped Bi₂O₃ using spray pyrolysis, a technique for producing fine solid particles. The results showed that Zr ions were doped into the Bi₂O₃ compound, resulting in the phase of Bi_7.38Zr_0.62O_12.31. The results of materials analysis showed Bi₂O₃ with 15 mol % of Zr doping increased its radiopacity (5.16 ± 0.2 mm Al) and mechanical strength, compared to Bi₂O₃ and other ratios of Zr-doped Bi₂O₃. To our knowledge, this is the first study of fabrication and analysis of Zr-doped Bi₂O₃ radiopacifiers through the spray pyrolysis procedure. The study reveals that spray pyrolysis can be a new technique for preparing Zr-doped Bi₂O₃ radiopacifiers for future dental applications.