Mineral trioxide aggregate, which comprises three major inorganic components, namely, tricalcium silicate (C3S), dicalcium silicate (C2S), and tricalcium aluminate (C3A), is promising regenerative cement for dentistry. While mineral trioxide aggregate has been successfully applied in retrograde filling, the exact role of each component in the mineral trioxide aggregate system is largely unexplored. In this study, we individually synthesized the three components, namely, C3S, C2A, and C3A, and then mixed them to achieve various compositions (a total of 14 compositions including those similar to mineral trioxide aggregate). All powders were fabricated to obtain high purity. The setting reaction of all cement compositions was within 40 min, which is shorter than for commercial mineral trioxide aggregate (~150 min). Over time, the pH of the composed cements initially showed an abrupt increase and then plateaued (pH 10-12), which is a typical behavior of mineral trioxide aggregate. The compression and tensile strength of the composed cements increased (2-4 times the initial values) with time for up to 21 days in an aqueous medium, the degree to which largely depended on the composition. The cell viability test with rat mesenchymal stem cells revealed no toxicity for any composition except C3A, which contained aluminum. To confirm the in vivo biological response, cement was retro-filled into an extracted rat tooth and the complex was re-implanted. Four weeks post-operation, histological assessments revealed that C3A caused significant tissue toxicity, while good tissue compatibility was observed with the other compositions. Taken together, these results reveal that of the three major constituents of mineral trioxide aggregate, C3A generated significant toxicity in vitro and in vivo, although it accelerated setting time. This study highlights the need for careful consideration with regard to the composition of mineral trioxide aggregate, and if possible (when other properties are satisfactory), the C3A component should be avoided, which can be achieved by the mixture of individual components.

中文翻译：

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重新配制的三氧化二矿物骨料成分以及用作未来牙科再生水泥的评估。

三氧化矿物骨料由三种主要无机成分组成，即硅酸三钙（C3S）、硅酸二钙（C2S）和铝酸三钙（C3A），是一种很有前途的牙科再生水泥。虽然三氧化二矿物骨料已成功应用于逆行填充，但三氧化二矿物骨料系统中每种成分的确切作用很大程度上尚未被探索。在本研究中，我们单独合成了三种组分，即C3S、C2A和C3A，然后将它们混合以获得各种组合物（包括与三氧化二矿物骨料类似的组合物，总共14种组合物）。所有粉末均经过加工以获得高纯度。所有水泥组合物的凝固反应均在 40 分钟内，这比商业三氧化二矿物骨料（约 150 分钟）要短。随着时间的推移，组成的水泥的 pH 值最初突然增加，然后趋于稳定（pH 10-12），这是三氧化二矿物骨料的典型行为。在水性介质中长达 21 天的时间内，复合水泥的压缩和拉伸强度随着时间的推移而增加（初始值的 2-4 倍），其程度很大程度上取决于成分。大鼠间充质干细胞的细胞活力测试显示，除​​了含有铝的 C3A 之外，任何组合物都没有毒性。为了确认体内生物反应，将水泥重新填充到拔出的大鼠牙齿中，并将复合物重新植入。术后四周，组织学评估显示C3A引起显着的组织毒性，同时观察到与其他组合物良好的组织相容性。综上所述，这些结果表明，在三氧化二矿物质聚集体的三种主要成分中，C3A 尽管加速了凝固时间，但在体外和体内产生了显着的毒性。这项研究强调需要仔细考虑三氧化二矿物骨料的组成，如果可能（当其他性能令人满意时），应避免使用C3A组分，这可以通过单独组分的混合物来实现。