AbstractZinc polycarboxylate cement (PAZ) was shown to actively bond to45Cain vitro, with maximum uptake occurring at a Ca+2concentration of 0.2 mg/ml. When the resultant PAZ‐45Ca complex was subsequently incubated in the presence of high levels of unlabeled Ca+2, there was an exchange between the45Ca bond to the cement and the Ca+2in solution. When PAZ prepared using65Zn was incubated with high levels of Ca+2, there was no exchange between the Ca and the65Zn.14C‐PA failed to be taken up by L‐cells in tissue culture, during 16 division cycles. Using radioactive PAZ prepared from14C‐PA, the PA moiety of the cement was shown to be extremely insoluble and stable