Biocompatibility of glass ionomer cements.

Glass ionomer cements (GICs) are widely used in the dental field and are increasingly being considered as materials with potentially good osteogenic properties. This paper details a comprehensive biocompatibility evaluation of a number of GICs. These include conventional, commercially available materials, novel formulations and a new light cured material. The experimental programme entailed in vitro cell culture studies using direct contact and extraction tests and an in vitro rat model in which the GICs were in intimate contact with bone for periods up to 8 wk. The results demonstrate clear differences between the materials and in particular highlight the poor cellular response to the light cured material. Methylthiazolyldiphenyl tetrazolium assay demonstrates stimulation of cell growth by some GIC formulations and indicates that cytotoxic leachable agents can be removed from others. The results obtained following implantation into bone are comprehensively presented using photomicrographs. New bone formation with time is demonstrated with a number of formulations.