US Patent No. 10,342,750 B2 (Michael Prencipe, Yun Xu, Xiao Yi Huang, Steven Fisher, Betty Won, Lyndsay Schaeffer-Korbylo); Colgate-Palmolive
has patented an oral care composition having synergistic zinc antibacterial effects. It is comprised of zinc oxide and zinc citrate. The zinc citrate is about 0.5% by weight of the composition, and the zinc oxide is about 1% by weight of the composition. The composition comprises a fluoride source selected from stannous fluoride, sodium fluoride, potassium fluoride, sodium fluorosilicate, ammonium fluorosilicate, amine fluoride, ammonium fluoride, titanium fluoride, and combinations thereof, and excludes any other fluoride source. The antibacterial effects are measured as reduction in colony forming units after the composition is applied to incubated hydroxyapatite disks and incubated for eight days. The antibacterial effects are measured after said hydroxyapatite disks are collected aseptically and transferred to a half-strength, pre-reduced, thioglycollate medium, according to the patent literature.