Osteoblasts and MG-63 osteosarcoma cells behave differently when in contact with ProRoot™ MTA and White MTA

Aim To test the hypothesis that MG-63 osteosarcoma cells and primary osteoblasts react differently to ProRoot(TM) MTA (mineral trioxide aggregate) and White MTA by: (i) investigating the attachment of primary osteoblasts and MG-63 osteosarcoma cells to ProRoot(TM) NITA and White MTA; and (ii) comparing the osteogenic behaviour of both cell lines in contact with these endodontic materials. Methodology Primary osteoblasts were harvested from foetal rat calvaria by sequential digestion and MG-63 osteosarcoma cells were purchased. Cells were exposed to ProRoot(TM) MTA and White MTA prepared according to the manufacturer's instructions. All samples and controls were prepared in quadruplicate. After 6, 9 and 13 days exposure to MTA, the cells were fixed and prepared for SEM examination. In addition, both the cell types were grown to confluence and exposed to beta-glycerophosphate and dexamethasone to assess mineralized nodule formation as a function of osteogenic behaviour. Results The number of cells on the surface of the culture dish and on top of the materials increased mall samples throughout the 3 time periods, except for White NITA where no primary osteoblasts were visible on top of the material by the end of 13 days. After exposing cells to differentiation medium nodules were observed in cultures of primary osteoblasts, but not of MG-63 osteosarcoma cells. Conclusions Under the conditions of this study, whilst primary osteoblasts initially bound to White NITA, they did not survive on the surface by the end of 13 days. Primary osteoblasts formed mineralized nodules when exposed to differentiation medium, whilst MG-63 cells did not form nodules. As MG-63 cells do not behave osteogenically by forming mineralized nodules. and primary osteoblasts are more sensitive than MG-63 osteosarcoma cells to White NITA in cell culture. primary osteoblasts are more appropriate than MG-63 cells for testing endodontic materials in cell culture.