Schmalz G, Langer H, Schweikl H
Department of Operative Dentistry and Periodontology, University of Regensburg, Germany.
J Dent Res. 1998 Oct;77(10):1772-8. doi: 10.1177/00220345980770100401.
Adverse tissue reactions of the gingiva and the periodontium close to dental cast alloys may be caused by the effects of released metal elements. Tissue reactions depend upon the amounts of elements available which are a function of corrosion rates. Since pH values of standard corrosion solutions are as low as 2.3, such extracts are a priori not biocompatible. In the present study, elements released from dental cast alloys into cell-culture media were determined, and the cytotoxicity of these medium extracts was compared with the effectiveness of metal salt solutions prepared according to the metal elements found in extracts. The elements Ag, Cu, Ni, and Zn were detected in extracts of dental alloys and copper (positive control) by inductively coupled plasma atomic emission spectrometry (ICP-AES). Medium extracts of dental alloys were non-toxic in mouse fibroblasts (L929 cells). However, the amounts of elements found in these extracts were weakly cytotoxic when tested as salt solutions prepared from chloride (Cu2+, Zn2+, Ni2+) or sulfate (Ag1+) salts. When the test specimens were heat-treated before extraction, extracts were clearly cytotoxic in a dose-related manner. Again, the amounts of elements that caused 50% cell death (TC50) were slightly lower in corresponding salt solutions than in extracts. In general, cytotoxicity of medium extracts consistently proved to be slightly less than that of the corresponding salt solutions, probably due to the limitations of the chemical analysis of extracts. This should be taken into account if salt solutions are used instead of the medium extract.
靠近牙科铸造合金的牙龈和牙周组织的不良反应可能是由释放的金属元素的影响引起的。组织反应取决于可用元素的量，而可用元素的量是腐蚀速率的函数。由于标准腐蚀溶液的pH值低至2.3，因此此类提取物在本质上是不具有生物相容性的。在本研究中，测定了牙科铸造合金释放到细胞培养基中的元素，并将这些培养基提取物的细胞毒性与根据提取物中发现的金属元素制备的金属盐溶液的有效性进行了比较。通过电感耦合等离子体原子发射光谱法（ICP-AES）在牙科合金和铜（阳性对照）的提取物中检测到了银、铜、镍和锌元素。牙科合金的培养基提取物对小鼠成纤维细胞（L929细胞）无毒。然而，当以氯化物（Cu2+、Zn2+、Ni2+）或硫酸盐（Ag1+）盐制备的盐溶液进行测试时，这些提取物中发现的元素量具有微弱的细胞毒性。当测试样品在提取前进行热处理时，提取物以剂量相关的方式明显具有细胞毒性。同样，导致50%细胞死亡（TC50）的元素量在相应的盐溶液中略低于提取物。一般来说，培养基提取物的细胞毒性始终被证明略低于相应的盐溶液，这可能是由于提取物化学分析的局限性。如果使用盐溶液代替培养基提取物，应考虑到这一点。
