The present invention relates to improved phosphopeptide stabilised amorphous calcium phosphate and/or amorphous calcium fluoride phosphate complexes and compositions containing those complexes. Methods of making the complexes of the invention and of treatment dental hypersensitivity are also provided. In one embodiment, the invention provides a stannous-associated phosphopeptide (PP) stabilized amorphous calcium phosphate (ACP) or amorphous calcium fluoride phosphate (ACFP) complex having a stannous ion content of equal to, or greater than, 1 mole of stannous per mole of PP but less than 4 moles of stannous per mole of PP.