Biocompatibility of a new mineral direct posterior restorative material

Objectives: a new material for direct restorative posterior fillings, a Ca₃SiO₅-based Portland cement, has been developed to circumvent the shortcomings of the traditional filling materials. The purpose of this work was to evaluate its genotoxicity, cytotoxicity, the effects on the specific functions of target cells and the marginal sealing. Methods: 1) Ames test was performed on four different species of salmonella typhimurium. Micronuclei test was performed on fresh human lymphocytes and Comet test was performed on human pulpal fibroblasts. 2) Cytotoxicity was tested according to ISO standards immediately after preparation and after 1 and 7 days with the MTT assay on human pulpal fibroblasts. 3) The effects on the specific functions of human pulp fibroblasts were investigated by studying the expression of collagen type I, Osteonectin, Dentin Sialoprotein and Nestin. 4) Marginal sealing was evaluated with the silver nitrate penetration method without any surface treatment with or without aging in artificial saliva. Results: Ames test did not show any evidence of mutagenicity. The rate of lymphocytes with micronuclei was similar to that obtained with the negative control. It ranged from 3.9% to 4.1% when diluted to 1 or 5% in aqueous or hydrophobic medium. The percentage of DNA in the queue with the comet test ranged from 12.59 for the 0.1% dilution to 15.58 with pure medium. The cytotoxicity of the material ranged from 10% at 1 day to 7% at 7 days, was similar MTA®, but less than Z250®. No difference in marginal sealing was revealed between the new biomaterial and Z250-Optibond solo plus® adhesive restorative system with or without aging for one week in artificial saliva. Conclusion: The material is non cytotoxic and non genotoxic for pulpal fibroblasts. The marginal sealing without any surface treatment or adhesive system is equivalent to the reference material used.