Methods
The participants were randomly grouped as: (1) Group N; no active ingredient-containing toothpaste as negative control (Pleasia fluoride-free; Amorepacific, Seoul, Korea), (2) Group SC; a commercially available toothpaste containing strontium chloride (Sensodyne Original; GlaxoSmithKline, Brendtford, UK), (3) Group TP; a commercially available toothpaste containing tricalcium phosphate (Vussen S; Osstem, Seoul, Korea). The composition of the experimental toothpastes used in this study is listed in Table Compositions of experimental materials.Pleasia fluoride-free(Amorepacific, korea)Main ingredient: sodium chlorideInactive ingredients: water, glycerin, sorbitol, hydrated silica, hydroxyethyl cellulose, cellulose gum, sodium lauryl sulfate, flavorSensodyne original(Glaxo SmithKline, korea)Active ingredient: 10% strontium chloride hexahydrateInactive ingredients: water, glycerin, sorbitol, calcium carbonate, hydroxyethyl cellulose, silicon dioxide, flavorVussen S(Osstem, korea)Active ingredient: 19% Tricalcium phosphateInactive ingredients: Water, sorbitol, hydrated silica, glycerin, cellulose gum, sodium lauryl sulfate, flavor