Scientific evidence

  • The benefits of zinc addition to mouthrinse preparations have been demonstrated in a number of studies. For example, a mouthrinse of 0.05% chlorhexidine, 0.05% cetylpyridinium chloride and 0.14% zinc lactate has been shown to be even more efficient than a 0.2% chlorhexidine formulation in reducing VSC levels and organoleptic ratings (Mitsui et al. 2003, Quirynen et al. 2002b, Winkel et al. 2003).
  • There appears to be a synergistic effect between zinc and other antibacterial agents; in one study a combined solution of 0.3% zinc acetate and 0.025% chlorhexidine was more effective in inhibiting VSC formation than either agent alone (Young et al. 2003a).
  • The use of chewing gum containing zinc acetate has also been shown to reduce levels of VSC (Wåler 1997b).
  • Rölla et al. (2002) have shown in vitro that zinc acetate and amino acid chelated zinc inhibited the release of hydrogen sulphide by almost three log units. Thus, the chelation of zinc by hydrogen sulphide obviously is very strong.
  • In agreement with the above results, insoluble zinc, copper and tin pyrophosphates inhibited VSC formation in saliva by 99-100% in vitro (Jonski et al. 2004). Furthermore, the pyrophosphate lost metal cations in water containing dissolved gases of hydrogen sulphide and methyl mercaptan. VSC formation was inhibited, supporting the hypothesis that sulphide ions are very strong ligands for zinc ions.