Improving the Radiopacity of Calcium Aluminate Cement Based Blends

The radiopacity of CAC-based compositions containing additives (ZnO, Ag and Bi2O3) was evaluated by optical density measurements, cold crushing strength, apparent porosity, pore size distribution, in vitro apatite-formation ability (bioactivity) and cell viability. The bioactivity was assessed via pH and calcium concentration measurements in simulated body fluid (SBF) for samples previously treated or not with sodium silicate (SS) solution. The surface of the samples after treatment was analyzed by scanning electron microscopy, energy dispersive X-ray analysis and confocal Raman spectroscopy. Cell viability was evaluated by MTT and alkaline phosphatase (ALP) activity. Radiopacity results confirmed that compositions containing ZnO-Ag (25:1 wt%) and ZnO-Bi2O3 (15:10 wt%) presented suitable values of radiopacity (> 3 mmAl). The identification of calcium and mainly phosphorus by EDX, highlighted the generation of an apatite-like layer on the compositions' surface after immersion in SBF or SBF/SS. CAC-blend containing 25 wt% ZnO, ZnO-Ag and ZnO-Bi2O3 presented slightly lower cell viability compared to the positive control.

本研究通过光密度测定、冷压强度、显气孔率、孔径分布、体外磷灰石形成能力（生物活性）以及细胞活力检测，对添加氧化锌（ZnO）、银（Ag）和三氧化二铋（Bi₂O₃）的CAC基复合材料的放射阻射性进行了评价。针对经硅酸钠（SS）溶液处理或未处理的样品，通过模拟体液（SBF）中的pH值与钙浓度测定评估其生物活性。采用扫描电子显微镜、能量色散X射线分析（EDX）以及共焦拉曼光谱对处理后的样品表面进行了表征分析。细胞活力通过噻唑蓝（MTT）比色法与碱性磷酸酶（ALP）活性检测进行评价。放射阻射性结果证实，添加ZnO-Ag（质量比25:1）与ZnO-Bi₂O₃（质量比15:10）的复合材料的放射阻射值符合要求（＞3mm铝当量）。通过EDX检测到钙及主要为磷的元素存在，表明样品在浸入SBF或SBF/SS溶液后，其表面生成了类磷灰石层。含有25wt% ZnO、ZnO-Ag及ZnO-Bi₂O₃的CAC共混复合材料的细胞活力略低于阳性对照组。