In vitro assessment of ni-cr and co-cr dental alloys upon recasting: cellular compatibility

The aim of this study was to evaluate the effect of recasting of commercially available Ni-Cr (Wiron 99) and Co-Cr (Dentalit C) dental alloys on physiology of microenvironmental cells. The viability of fibrosarcoma (L929) cells, human embrional fibroblasts (MRC-5) and isolated peripheral blood mononuclear cells (PBMC) was measured by MTT and acidic phosphatase tests. Presence of dying cells was estimated by Annexin/PI staining while the production of intracellular nitric oxide (NO), reactive oxygen (ROS) and nitrogen (RNS) species was determined by DAF-FM diacetate and DHR staining. Recasting of Ni-Cr alloy intensified its cytotoxicity manifested through enhanced free radicals production, induction of cell death and permamently diminished cell proliferation. On the other hand, after initial toxic effect cells adapted to the presence of Co-Cr alloys. Independently of recasting, Co-Cr alloys are more compatible with microenvironment then Ni-Cr alloy. Oppositely, recasting of Ni-Cr alloy promoted its toxicity