Biological tests of a silicophosphate cement.

The biological compatibility of a silicophosphate cement (Fluoro-Thin) and a zinc phosphate cement (de Trey's Improved) has been assessed in in vitro (cell culture) and in vivo (monkey teeth) tests. In the in vitro tests both materials were toxic when freshly prepared. In experiments with prolonged cell-material contact time, with set specimens of the materials, the zinc phosphate cement appeared to be non-toxic, whereas the silicophosphate cement was clearly toxic. The in vivo experiments confirmed that a possible pulp reaction cauded by zinc phosphate cement is of a mild nature. The silicophosphate cement, however, cauded a moderate or severe reaction in the pulp after 8 days of observation, and there was chronic inflammation in most teeth after 36 or 72 days. It was concluded, therefore, that Fluoro-Thin should not be used as a luting agent or for restorative purposes in direct contact with vital dentine.