Mode of action of zinc ions

  • The anti-VSC effect of zinc salts has been associated with the presence of free zinc ions. However, the degree of dissociation of different zinc salts is not related to the anti-VSC effect.
  • Salts with high stability constants provide few zinc ions upon dissolution in water, while salts with low stability constants provide more free zinc ions upon dissolution in water.
  • A study of lozenges containing zinc acetate, zinc gluconate, zinc citrate or an amino acid chelate of zinc (stability constants ranging from very low to very high) showed that zinc salts with high stability constants were as effective at producing an anti-VSC effect as zinc salts with low stability constants (Rölla et al. 2002).
  • The results suggest that strong competitive ligands with high affinity for zinc ions may displace the original ligand present in the lozenge according to the model ZnL1 + L2 > ZnL2 + L1. Ligands that may be present in the oral cavity include the sulphide ion.