An in vitro model for testing biocompatibility of endodontic materials to bone

Calvaria from 6-day old mice labelled 4 days previously with 45CaCl2 were divided into test and control halves and each half cultured separately in vitro. Eluents from four endodontic materials, endomethasone, zinc oxide/eugenol, AH26 and gutta-percha were added separately to the culture medium of each test half. After 24 and 48 h culturing periods, the 45CaCl2 in the media and calvaria was measured by a standard liquid scintillation counting technique and a resorption ratio between test and control halves was computed. This ratio, based on cell mediated resorption, was an indication of toxicity of soluble components of each endodontic material. In accordance with the literature, endomethasone was found, with our method, to be the most toxic and gutta-percha the least toxic of the materials tested. This shows that our model can be used to test the toxicity of other biomaterials to bone cells in vitro.