Bueno Carlos Eduardo da Silveira, Zeferino Eduardo Gregatto, Manhães Luiz Roberto Coutinho, Rocha Daniel Guimarães Pedro, Cunha Rodrigo Sanches, De Martin Alexandre Sigrist
Center for Dental Research, São Leopoldo Mandic University, Campinas, Brazil.
Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2009 Jan;107(1):e65-9. doi: 10.1016/j.tripleo.2008.09.016.
The purpose of this study was to determine the ideal concentration of bismuth oxide in white Portland cement to provide it with sufficient radiopacity for use as an endodontic material (ADA specification #57).
2-mm thick standardized test specimens of white MTA and of white Portland cement, as controls, and of white Portland cement with the experimental addition of 5%, 10%, 15%, 20%, 25% or 30% of bismuth oxide were radiographed and compared with various thicknesses of pure aluminum, using optic density to determine the observed grayscale levels of radiopacity in a scale ranging from 0 to 255. The data was submitted to ANOVA (p<0.05) and the Ryan-Einot-Gabriel-Welch and Quiot test (REGWQ) for multiple comparison of the means.
White Portland cement with 0%, 5%, 10%, 15%, 20%, 25% and 30% of bismuth oxide presented mean readings of 63.3, 95.7, 110.7, 142.7, 151.3, 161.0 and 180.0 respectively. MTA presented a mean reading of 157.3. The readings of MTA and white Portland cement with 15% bismuth oxide did not differ significantly from the reading observed for a thickness of 4 mm of aluminum (145.3), which is considered ideal for a test specimen by ADA specification #57 (2 mm above the thickness of the test specimen).
White MTA and white Portland cement with 15% bismuth oxide presented the radiopacity required for an endodontic cement.
本研究的目的是确定白色波特兰水泥中氧化铋的理想浓度，使其具有足够的射线不透性，以用作牙髓材料（ADA规范#57）。
对白色MTA、白色波特兰水泥（作为对照）以及添加了5%、10%、15%、20%、25%或30%氧化铋的白色波特兰水泥制成的2毫米厚标准测试样本进行射线照相，并与不同厚度的纯铝进行比较，使用光密度来确定在0至255范围内观察到的射线不透性灰度水平。数据提交给方差分析（p<0.05）以及用于均值多重比较的Ryan-Einot-Gabriel-Welch和Quiot检验（REGWQ）。
氧化铋含量为0%、5%、10%、15%、20%、25%和30%的白色波特兰水泥的平均读数分别为63.3、95.7、110.7、142.7、151.3、161.0和180.0。MTA的平均读数为157.3。MTA和氧化铋含量为15%的白色波特兰水泥的读数与4毫米厚铝的读数（145.3）无显著差异，根据ADA规范#57（比测试样本厚度厚2毫米），这被认为是测试样本的理想读数。
白色MTA和氧化铋含量为15%的白色波特兰水泥呈现出牙髓水泥所需的射线不透性。
